diff options
Diffstat (limited to 'pkg/state')
37 files changed, 6203 insertions, 0 deletions
diff --git a/pkg/state/BUILD b/pkg/state/BUILD new file mode 100644 index 000000000..089b3bbef --- /dev/null +++ b/pkg/state/BUILD @@ -0,0 +1,100 @@ +load("//tools:defs.bzl", "go_library") +load("//tools/go_generics:defs.bzl", "go_template_instance") + +package(licenses = ["notice"]) + +go_template_instance( + name = "pending_list", + out = "pending_list.go", + package = "state", + prefix = "pending", + template = "//pkg/ilist:generic_list", + types = { + "Element": "*objectEncodeState", + "ElementMapper": "pendingMapper", + "Linker": "*pendingEntry", + }, +) + +go_template_instance( + name = "deferred_list", + out = "deferred_list.go", + package = "state", + prefix = "deferred", + template = "//pkg/ilist:generic_list", + types = { + "Element": "*objectEncodeState", + "ElementMapper": "deferredMapper", + "Linker": "*deferredEntry", + }, +) + +go_template_instance( + name = "complete_list", + out = "complete_list.go", + package = "state", + prefix = "complete", + template = "//pkg/ilist:generic_list", + types = { + "Element": "*objectDecodeState", + "Linker": "*objectDecodeState", + }, +) + +go_template_instance( + name = "addr_range", + out = "addr_range.go", + package = "state", + prefix = "addr", + template = "//pkg/segment:generic_range", + types = { + "T": "uintptr", + }, +) + +go_template_instance( + name = "addr_set", + out = "addr_set.go", + consts = { + "minDegree": "10", + }, + imports = { + "reflect": "reflect", + }, + package = "state", + prefix = "addr", + template = "//pkg/segment:generic_set", + types = { + "Key": "uintptr", + "Range": "addrRange", + "Value": "*objectEncodeState", + "Functions": "addrSetFunctions", + }, +) + +go_library( + name = "state", + srcs = [ + "addr_range.go", + "addr_set.go", + "complete_list.go", + "decode.go", + "decode_unsafe.go", + "deferred_list.go", + "encode.go", + "encode_unsafe.go", + "pending_list.go", + "state.go", + "state_norace.go", + "state_race.go", + "stats.go", + "types.go", + ], + marshal = False, + stateify = False, + visibility = ["//:sandbox"], + deps = [ + "//pkg/log", + "//pkg/state/wire", + ], +) diff --git a/pkg/state/README.md b/pkg/state/README.md new file mode 100644 index 000000000..1aa401193 --- /dev/null +++ b/pkg/state/README.md @@ -0,0 +1,158 @@ +# State Encoding and Decoding + +The state package implements the encoding and decoding of data structures for +`go_stateify`. This package is designed for use cases other than the standard +encoding packages, e.g. `gob` and `json`. Principally: + +* This package operates on complex object graphs and accurately serializes and + restores all relationships. That is, you can have things like: intrusive + pointers, cycles, and pointer chains of arbitrary depths. These are not + handled appropriately by existing encoders. This is not an implementation + flaw: the formats themselves are not capable of representing these graphs, + as they can only generate directed trees. + +* This package allows installing order-dependent load callbacks and then + resolves that graph at load time, with cycle detection. Similarly, there is + no analogous feature possible in the standard encoders. + +* This package handles the resolution of interfaces, based on a registered + type name. For interface objects type information is saved in the serialized + format. This is generally true for `gob` as well, but it works differently. + +Here's an overview of how encoding and decoding works. + +## Encoding + +Encoding produces a `statefile`, which contains a list of chunks of the form +`(header, payload)`. The payload can either be some raw data, or a series of +encoded wire objects representing some object graph. All encoded objects are +defined in the `wire` subpackage. + +Encoding of an object graph begins with `encodeState.Save`. + +### 1. Memory Map & Encoding + +To discover relationships between potentially interdependent data structures +(for example, a struct may contain pointers to members of other data +structures), the encoder first walks the object graph and constructs a memory +map of the objects in the input graph. As this walk progresses, objects are +queued in the `pending` list and items are placed on the `deferred` list as they +are discovered. No single object will be encoded multiple times, but the +discovered relationships between objects may change as more parts of the overall +object graph are discovered. + +The encoder starts at the root object and recursively visits all reachable +objects, recording the address ranges containing the underlying data for each +object. This is stored as a segment set (`addrSet`), mapping address ranges to +the of the object occupying the range; see `encodeState.values`. Note that there +is special handling for zero-sized types and map objects during this process. + +Additionally, the encoder assigns each object a unique identifier which is used +to indicate relationships between objects in the statefile; see `objectID` in +`encode.go`. + +### 2. Type Serialization + +The enoder will subsequently serialize all information about discovered types, +including field names. These are used during decoding to reconcile these types +with other internally registered types. + +### 3. Object Serialization + +With a full address map, and all objects correctly encoded, all object encodings +are serialized. The assigned `objectID`s aren't explicitly encoded in the +statefile. The order of object messages in the stream determine their IDs. + +### Example + +Given the following data structure definitions: + +```go +type system struct { + o *outer + i *inner +} + +type outer struct { + a int64 + cn *container +} + +type container struct { + n uint64 + elem *inner +} + +type inner struct { + c container + x, y uint64 +} +``` + +Initialized like this: + +```go +o := outer{ + a: 10, + cn: nil, +} +i := inner{ + x: 20, + y: 30, + c: container{}, +} +s := system{ + o: &o, + i: &i, +} + +o.cn = &i.c +o.cn.elem = &i + +``` + +Encoding will produce an object stream like this: + +``` +g0r1 = struct{ + i: g0r3, + o: g0r2, +} +g0r2 = struct{ + a: 10, + cn: g0r3.c, +} +g0r3 = struct{ + c: struct{ + elem: g0r3, + n: 0u, + }, + x: 20u, + y: 30u, +} +``` + +Note how `g0r3.c` is correctly encoded as the underlying `container` object for +`inner.c`, and how the pointer from `outer.cn` points to it, despite `system.i` +being discovered after the pointer to it in `system.o.cn`. Also note that +decoding isn't strictly reliant on the order of encoded object stream, as long +as the relationship between objects are correctly encoded. + +## Decoding + +Decoding reads the statefile and reconstructs the object graph. Decoding begins +in `decodeState.Load`. Decoding is performed in a single pass over the object +stream in the statefile, and a subsequent pass over all deserialized objects is +done to fire off all loading callbacks in the correctly defined order. Note that +introducing cycles is possible here, but these are detected and an error will be +returned. + +Decoding is relatively straight forward. For most primitive values, the decoder +constructs an appropriate object and fills it with the values encoded in the +statefile. Pointers need special handling, as they must point to a value +allocated elsewhere. When values are constructed, the decoder indexes them by +their `objectID`s in `decodeState.objectsByID`. The target of pointers are +resolved by searching for the target in this index by their `objectID`; see +`decodeState.register`. For pointers to values inside another value (fields in a +pointer, elements of an array), the decoder uses the accessor path to walk to +the appropriate location; see `walkChild`. diff --git a/pkg/state/decode.go b/pkg/state/decode.go new file mode 100644 index 000000000..c9971cdf6 --- /dev/null +++ b/pkg/state/decode.go @@ -0,0 +1,725 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package state + +import ( + "bytes" + "context" + "fmt" + "math" + "reflect" + + "gvisor.dev/gvisor/pkg/state/wire" +) + +// internalCallback is a interface called on object completion. +// +// There are two implementations: objectDecodeState & userCallback. +type internalCallback interface { + // source returns the dependent object. May be nil. + source() *objectDecodeState + + // callbackRun executes the callback. + callbackRun() +} + +// userCallback is an implementation of internalCallback. +type userCallback func() + +// source implements internalCallback.source. +func (userCallback) source() *objectDecodeState { + return nil +} + +// callbackRun implements internalCallback.callbackRun. +func (uc userCallback) callbackRun() { + uc() +} + +// objectDecodeState represents an object that may be in the process of being +// decoded. Specifically, it represents either a decoded object, or an an +// interest in a future object that will be decoded. When that interest is +// registered (via register), the storage for the object will be created, but +// it will not be decoded until the object is encountered in the stream. +type objectDecodeState struct { + // id is the id for this object. + id objectID + + // typ is the id for this typeID. This may be zero if this is not a + // type-registered structure. + typ typeID + + // obj is the object. This may or may not be valid yet, depending on + // whether complete returns true. However, regardless of whether the + // object is valid, obj contains a final storage location for the + // object. This is immutable. + // + // Note that this must be addressable (obj.Addr() must not panic). + // + // The obj passed to the decode methods below will equal this obj only + // in the case of decoding the top-level object. However, the passed + // obj may represent individual fields, elements of a slice, etc. that + // are effectively embedded within the reflect.Value below but with + // distinct types. + obj reflect.Value + + // blockedBy is the number of dependencies this object has. + blockedBy int + + // callbacksInline is inline storage for callbacks. + callbacksInline [2]internalCallback + + // callbacks is a set of callbacks to execute on load. + callbacks []internalCallback + + completeEntry +} + +// addCallback adds a callback to the objectDecodeState. +func (ods *objectDecodeState) addCallback(ic internalCallback) { + if ods.callbacks == nil { + ods.callbacks = ods.callbacksInline[:0] + } + ods.callbacks = append(ods.callbacks, ic) +} + +// findCycleFor returns when the given object is found in the blocking set. +func (ods *objectDecodeState) findCycleFor(target *objectDecodeState) []*objectDecodeState { + for _, ic := range ods.callbacks { + other := ic.source() + if other != nil && other == target { + return []*objectDecodeState{target} + } else if childList := other.findCycleFor(target); childList != nil { + return append(childList, other) + } + } + + // This should not occur. + Failf("no deadlock found?") + panic("unreachable") +} + +// findCycle finds a dependency cycle. +func (ods *objectDecodeState) findCycle() []*objectDecodeState { + return append(ods.findCycleFor(ods), ods) +} + +// source implements internalCallback.source. +func (ods *objectDecodeState) source() *objectDecodeState { + return ods +} + +// callbackRun implements internalCallback.callbackRun. +func (ods *objectDecodeState) callbackRun() { + ods.blockedBy-- +} + +// decodeState is a graph of objects in the process of being decoded. +// +// The decode process involves loading the breadth-first graph generated by +// encode. This graph is read in it's entirety, ensuring that all object +// storage is complete. +// +// As the graph is being serialized, a set of completion callbacks are +// executed. These completion callbacks should form a set of acyclic subgraphs +// over the original one. After decoding is complete, the objects are scanned +// to ensure that all callbacks are executed, otherwise the callback graph was +// not acyclic. +type decodeState struct { + // ctx is the decode context. + ctx context.Context + + // r is the input stream. + r wire.Reader + + // types is the type database. + types typeDecodeDatabase + + // objectByID is the set of objects in progress. + objectsByID []*objectDecodeState + + // deferred are objects that have been read, by no interest has been + // registered yet. These will be decoded once interest in registered. + deferred map[objectID]wire.Object + + // pending is the set of objects that are not yet complete. + pending completeList + + // stats tracks time data. + stats Stats +} + +// lookup looks up an object in decodeState or returns nil if no such object +// has been previously registered. +func (ds *decodeState) lookup(id objectID) *objectDecodeState { + if len(ds.objectsByID) < int(id) { + return nil + } + return ds.objectsByID[id-1] +} + +// checkComplete checks for completion. +func (ds *decodeState) checkComplete(ods *objectDecodeState) bool { + // Still blocked? + if ods.blockedBy > 0 { + return false + } + + // Track stats if relevant. + if ods.callbacks != nil && ods.typ != 0 { + ds.stats.start(ods.typ) + defer ds.stats.done() + } + + // Fire all callbacks. + for _, ic := range ods.callbacks { + ic.callbackRun() + } + + // Mark completed. + cbs := ods.callbacks + ods.callbacks = nil + ds.pending.Remove(ods) + + // Recursively check others. + for _, ic := range cbs { + if other := ic.source(); other != nil && other.blockedBy == 0 { + ds.checkComplete(other) + } + } + + return true // All set. +} + +// wait registers a dependency on an object. +// +// As a special case, we always allow _useable_ references back to the first +// decoding object because it may have fields that are already decoded. We also +// allow trivial self reference, since they can be handled internally. +func (ds *decodeState) wait(waiter *objectDecodeState, id objectID, callback func()) { + switch id { + case waiter.id: + // Trivial self reference. + fallthrough + case 1: + // Root object; see above. + if callback != nil { + callback() + } + return + } + + // Mark as blocked. + waiter.blockedBy++ + + // No nil can be returned here. + other := ds.lookup(id) + if callback != nil { + // Add the additional user callback. + other.addCallback(userCallback(callback)) + } + + // Mark waiter as unblocked. + other.addCallback(waiter) +} + +// waitObject notes a blocking relationship. +func (ds *decodeState) waitObject(ods *objectDecodeState, encoded wire.Object, callback func()) { + if rv, ok := encoded.(*wire.Ref); ok && rv.Root != 0 { + // Refs can encode pointers and maps. + ds.wait(ods, objectID(rv.Root), callback) + } else if sv, ok := encoded.(*wire.Slice); ok && sv.Ref.Root != 0 { + // See decodeObject; we need to wait for the array (if non-nil). + ds.wait(ods, objectID(sv.Ref.Root), callback) + } else if iv, ok := encoded.(*wire.Interface); ok { + // It's an interface (wait recurisvely). + ds.waitObject(ods, iv.Value, callback) + } else if callback != nil { + // Nothing to wait for: execute the callback immediately. + callback() + } +} + +// walkChild returns a child object from obj, given an accessor path. This is +// the decode-side equivalent to traverse in encode.go. +// +// For the purposes of this function, a child object is either a field within a +// struct or an array element, with one such indirection per element in +// path. The returned value may be an unexported field, so it may not be +// directly assignable. See unsafePointerTo. +func walkChild(path []wire.Dot, obj reflect.Value) reflect.Value { + // See wire.Ref.Dots. The path here is specified in reverse order. + for i := len(path) - 1; i >= 0; i-- { + switch pc := path[i].(type) { + case *wire.FieldName: // Must be a pointer. + if obj.Kind() != reflect.Struct { + Failf("next component in child path is a field name, but the current object is not a struct. Path: %v, current obj: %#v", path, obj) + } + obj = obj.FieldByName(string(*pc)) + case wire.Index: // Embedded. + if obj.Kind() != reflect.Array { + Failf("next component in child path is an array index, but the current object is not an array. Path: %v, current obj: %#v", path, obj) + } + obj = obj.Index(int(pc)) + default: + panic("unreachable: switch should be exhaustive") + } + } + return obj +} + +// register registers a decode with a type. +// +// This type is only used to instantiate a new object if it has not been +// registered previously. This depends on the type provided if none is +// available in the object itself. +func (ds *decodeState) register(r *wire.Ref, typ reflect.Type) reflect.Value { + // Grow the objectsByID slice. + id := objectID(r.Root) + if len(ds.objectsByID) < int(id) { + ds.objectsByID = append(ds.objectsByID, make([]*objectDecodeState, int(id)-len(ds.objectsByID))...) + } + + // Does this object already exist? + ods := ds.objectsByID[id-1] + if ods != nil { + return walkChild(r.Dots, ods.obj) + } + + // Create the object. + if len(r.Dots) != 0 { + typ = ds.findType(r.Type) + } + v := reflect.New(typ) + ods = &objectDecodeState{ + id: id, + obj: v.Elem(), + } + ds.objectsByID[id-1] = ods + ds.pending.PushBack(ods) + + // Process any deferred objects & callbacks. + if encoded, ok := ds.deferred[id]; ok { + delete(ds.deferred, id) + ds.decodeObject(ods, ods.obj, encoded) + } + + return walkChild(r.Dots, ods.obj) +} + +// objectDecoder is for decoding structs. +type objectDecoder struct { + // ds is decodeState. + ds *decodeState + + // ods is current object being decoded. + ods *objectDecodeState + + // reconciledTypeEntry is the reconciled type information. + rte *reconciledTypeEntry + + // encoded is the encoded object state. + encoded *wire.Struct +} + +// load is helper for the public methods on Source. +func (od *objectDecoder) load(slot int, objPtr reflect.Value, wait bool, fn func()) { + // Note that we have reconciled the type and may remap the fields here + // to match what's expected by the decoder. The "slot" parameter here + // is in terms of the local type, where the fields in the encoded + // object are in terms of the wire object's type, which might be in a + // different order (but will have the same fields). + v := *od.encoded.Field(od.rte.FieldOrder[slot]) + od.ds.decodeObject(od.ods, objPtr.Elem(), v) + if wait { + // Mark this individual object a blocker. + od.ds.waitObject(od.ods, v, fn) + } +} + +// aterLoad implements Source.AfterLoad. +func (od *objectDecoder) afterLoad(fn func()) { + // Queue the local callback; this will execute when all of the above + // data dependencies have been cleared. + od.ods.addCallback(userCallback(fn)) +} + +// decodeStruct decodes a struct value. +func (ds *decodeState) decodeStruct(ods *objectDecodeState, obj reflect.Value, encoded *wire.Struct) { + if encoded.TypeID == 0 { + // Allow anonymous empty structs, but only if the encoded + // object also has no fields. + if encoded.Fields() == 0 && obj.NumField() == 0 { + return + } + + // Propagate an error. + Failf("empty struct on wire %#v has field mismatch with type %q", encoded, obj.Type().Name()) + } + + // Lookup the object type. + rte := ds.types.Lookup(typeID(encoded.TypeID), obj.Type()) + ods.typ = typeID(encoded.TypeID) + + // Invoke the loader. + od := objectDecoder{ + ds: ds, + ods: ods, + rte: rte, + encoded: encoded, + } + ds.stats.start(ods.typ) + defer ds.stats.done() + if sl, ok := obj.Addr().Interface().(SaverLoader); ok { + // Note: may be a registered empty struct which does not + // implement the saver/loader interfaces. + sl.StateLoad(Source{internal: od}) + } +} + +// decodeMap decodes a map value. +func (ds *decodeState) decodeMap(ods *objectDecodeState, obj reflect.Value, encoded *wire.Map) { + if obj.IsNil() { + // See pointerTo. + obj.Set(reflect.MakeMap(obj.Type())) + } + for i := 0; i < len(encoded.Keys); i++ { + // Decode the objects. + kv := reflect.New(obj.Type().Key()).Elem() + vv := reflect.New(obj.Type().Elem()).Elem() + ds.decodeObject(ods, kv, encoded.Keys[i]) + ds.decodeObject(ods, vv, encoded.Values[i]) + ds.waitObject(ods, encoded.Keys[i], nil) + ds.waitObject(ods, encoded.Values[i], nil) + + // Set in the map. + obj.SetMapIndex(kv, vv) + } +} + +// decodeArray decodes an array value. +func (ds *decodeState) decodeArray(ods *objectDecodeState, obj reflect.Value, encoded *wire.Array) { + if len(encoded.Contents) != obj.Len() { + Failf("mismatching array length expect=%d, actual=%d", obj.Len(), len(encoded.Contents)) + } + // Decode the contents into the array. + for i := 0; i < len(encoded.Contents); i++ { + ds.decodeObject(ods, obj.Index(i), encoded.Contents[i]) + ds.waitObject(ods, encoded.Contents[i], nil) + } +} + +// findType finds the type for the given wire.TypeSpecs. +func (ds *decodeState) findType(t wire.TypeSpec) reflect.Type { + switch x := t.(type) { + case wire.TypeID: + typ := ds.types.LookupType(typeID(x)) + rte := ds.types.Lookup(typeID(x), typ) + return rte.LocalType + case *wire.TypeSpecPointer: + return reflect.PtrTo(ds.findType(x.Type)) + case *wire.TypeSpecArray: + return reflect.ArrayOf(int(x.Count), ds.findType(x.Type)) + case *wire.TypeSpecSlice: + return reflect.SliceOf(ds.findType(x.Type)) + case *wire.TypeSpecMap: + return reflect.MapOf(ds.findType(x.Key), ds.findType(x.Value)) + default: + // Should not happen. + Failf("unknown type %#v", t) + } + panic("unreachable") +} + +// decodeInterface decodes an interface value. +func (ds *decodeState) decodeInterface(ods *objectDecodeState, obj reflect.Value, encoded *wire.Interface) { + if _, ok := encoded.Type.(wire.TypeSpecNil); ok { + // Special case; the nil object. Just decode directly, which + // will read nil from the wire (if encoded correctly). + ds.decodeObject(ods, obj, encoded.Value) + return + } + + // We now need to resolve the actual type. + typ := ds.findType(encoded.Type) + + // We need to imbue type information here, then we can proceed to + // decode normally. In order to avoid issues with setting value-types, + // we create a new non-interface version of this object. We will then + // set the interface object to be equal to whatever we decode. + origObj := obj + obj = reflect.New(typ).Elem() + defer origObj.Set(obj) + + // With the object now having sufficient type information to actually + // have Set called on it, we can proceed to decode the value. + ds.decodeObject(ods, obj, encoded.Value) +} + +// isFloatEq determines if x and y represent the same value. +func isFloatEq(x float64, y float64) bool { + switch { + case math.IsNaN(x): + return math.IsNaN(y) + case math.IsInf(x, 1): + return math.IsInf(y, 1) + case math.IsInf(x, -1): + return math.IsInf(y, -1) + default: + return x == y + } +} + +// isComplexEq determines if x and y represent the same value. +func isComplexEq(x complex128, y complex128) bool { + return isFloatEq(real(x), real(y)) && isFloatEq(imag(x), imag(y)) +} + +// decodeObject decodes a object value. +func (ds *decodeState) decodeObject(ods *objectDecodeState, obj reflect.Value, encoded wire.Object) { + switch x := encoded.(type) { + case wire.Nil: // Fast path: first. + // We leave obj alone here. That's because if obj represents an + // interface, it may have been imbued with type information in + // decodeInterface, and we don't want to destroy that. + case *wire.Ref: + // Nil pointers may be encoded in a "forceValue" context. For + // those we just leave it alone as the value will already be + // correct (nil). + if id := objectID(x.Root); id == 0 { + return + } + + // Note that if this is a map type, we go through a level of + // indirection to allow for map aliasing. + if obj.Kind() == reflect.Map { + v := ds.register(x, obj.Type()) + if v.IsNil() { + // Note that we don't want to clobber the map + // if has already been decoded by decodeMap. We + // just make it so that we have a consistent + // reference when that eventually does happen. + v.Set(reflect.MakeMap(v.Type())) + } + obj.Set(v) + return + } + + // Normal assignment: authoritative only if no dots. + v := ds.register(x, obj.Type().Elem()) + if v.IsValid() { + obj.Set(unsafePointerTo(v)) + } + case wire.Bool: + obj.SetBool(bool(x)) + case wire.Int: + obj.SetInt(int64(x)) + if obj.Int() != int64(x) { + Failf("signed integer truncated from %v to %v", int64(x), obj.Int()) + } + case wire.Uint: + obj.SetUint(uint64(x)) + if obj.Uint() != uint64(x) { + Failf("unsigned integer truncated from %v to %v", uint64(x), obj.Uint()) + } + case wire.Float32: + obj.SetFloat(float64(x)) + case wire.Float64: + obj.SetFloat(float64(x)) + if !isFloatEq(obj.Float(), float64(x)) { + Failf("floating point number truncated from %v to %v", float64(x), obj.Float()) + } + case *wire.Complex64: + obj.SetComplex(complex128(*x)) + case *wire.Complex128: + obj.SetComplex(complex128(*x)) + if !isComplexEq(obj.Complex(), complex128(*x)) { + Failf("complex number truncated from %v to %v", complex128(*x), obj.Complex()) + } + case *wire.String: + obj.SetString(string(*x)) + case *wire.Slice: + // See *wire.Ref above; same applies. + if id := objectID(x.Ref.Root); id == 0 { + return + } + // Note that it's fine to slice the array here and assume that + // contents will still be filled in later on. + typ := reflect.ArrayOf(int(x.Capacity), obj.Type().Elem()) // The object type. + v := ds.register(&x.Ref, typ) + obj.Set(v.Slice3(0, int(x.Length), int(x.Capacity))) + case *wire.Array: + ds.decodeArray(ods, obj, x) + case *wire.Struct: + ds.decodeStruct(ods, obj, x) + case *wire.Map: + ds.decodeMap(ods, obj, x) + case *wire.Interface: + ds.decodeInterface(ods, obj, x) + default: + // Shoud not happen, not propagated as an error. + Failf("unknown object %#v for %q", encoded, obj.Type().Name()) + } +} + +// Load deserializes the object graph rooted at obj. +// +// This function may panic and should be run in safely(). +func (ds *decodeState) Load(obj reflect.Value) { + ds.stats.init() + defer ds.stats.fini(func(id typeID) string { + return ds.types.LookupName(id) + }) + + // Create the root object. + ds.objectsByID = append(ds.objectsByID, &objectDecodeState{ + id: 1, + obj: obj, + }) + + // Read the number of objects. + lastID, object, err := ReadHeader(ds.r) + if err != nil { + Failf("header error: %w", err) + } + if !object { + Failf("object missing") + } + + // Decode all objects. + var ( + encoded wire.Object + ods *objectDecodeState + id = objectID(1) + tid = typeID(1) + ) + if err := safely(func() { + // Decode all objects in the stream. + // + // Note that the structure of this decoding loop should match + // the raw decoding loop in printer.go. + for id <= objectID(lastID) { + // Unmarshal the object. + encoded = wire.Load(ds.r) + + // Is this a type object? Handle inline. + if wt, ok := encoded.(*wire.Type); ok { + ds.types.Register(wt) + tid++ + encoded = nil + continue + } + + // Actually resolve the object. + ods = ds.lookup(id) + if ods != nil { + // Decode the object. + ds.decodeObject(ods, ods.obj, encoded) + } else { + // If an object hasn't had interest registered + // previously or isn't yet valid, we deferred + // decoding until interest is registered. + ds.deferred[id] = encoded + } + + // For error handling. + ods = nil + encoded = nil + id++ + } + }); err != nil { + // Include as much information as we can, taking into account + // the possible state transitions above. + if ods != nil { + Failf("error decoding object ID %d (%T) from %#v: %w", id, ods.obj.Interface(), encoded, err) + } else if encoded != nil { + Failf("lookup error decoding object ID %d from %#v: %w", id, encoded, err) + } else { + Failf("general decoding error: %w", err) + } + } + + // Check if we have any deferred objects. + for id, encoded := range ds.deferred { + // Shoud never happen, the graph was bogus. + Failf("still have deferred objects: one is ID %d, %#v", id, encoded) + } + + // Scan and fire all callbacks. We iterate over the list of incomplete + // objects until all have been finished. We stop iterating if no + // objects become complete (there is a dependency cycle). + // + // Note that we iterate backwards here, because there will be a strong + // tendendcy for blocking relationships to go from earlier objects to + // later (deeper) objects in the graph. This will reduce the number of + // iterations required to finish all objects. + if err := safely(func() { + for ds.pending.Back() != nil { + thisCycle := false + for ods = ds.pending.Back(); ods != nil; { + if ds.checkComplete(ods) { + thisCycle = true + break + } + ods = ods.Prev() + } + if !thisCycle { + break + } + } + }); err != nil { + Failf("error executing callbacks for %#v: %w", ods.obj.Interface(), err) + } + + // Check if we have any remaining dependency cycles. If there are any + // objects left in the pending list, then it must be due to a cycle. + if ods := ds.pending.Front(); ods != nil { + // This must be the result of a dependency cycle. + cycle := ods.findCycle() + var buf bytes.Buffer + buf.WriteString("dependency cycle: {") + for i, cycleOS := range cycle { + if i > 0 { + buf.WriteString(" => ") + } + fmt.Fprintf(&buf, "%q", cycleOS.obj.Type()) + } + buf.WriteString("}") + Failf("incomplete graph: %s", string(buf.Bytes())) + } +} + +// ReadHeader reads an object header. +// +// Each object written to the statefile is prefixed with a header. See +// WriteHeader for more information; these functions are exported to allow +// non-state writes to the file to play nice with debugging tools. +func ReadHeader(r wire.Reader) (length uint64, object bool, err error) { + // Read the header. + err = safely(func() { + length = wire.LoadUint(r) + }) + if err != nil { + // On the header, pass raw I/O errors. + if sErr, ok := err.(*ErrState); ok { + return 0, false, sErr.Unwrap() + } + } + + // Decode whether the object is valid. + object = length&objectFlag != 0 + length &^= objectFlag + return +} diff --git a/pkg/state/decode_unsafe.go b/pkg/state/decode_unsafe.go new file mode 100644 index 000000000..d048f61a1 --- /dev/null +++ b/pkg/state/decode_unsafe.go @@ -0,0 +1,27 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package state + +import ( + "reflect" + "unsafe" +) + +// unsafePointerTo is logically equivalent to reflect.Value.Addr, but works on +// values representing unexported fields. This bypasses visibility, but not +// type safety. +func unsafePointerTo(obj reflect.Value) reflect.Value { + return reflect.NewAt(obj.Type(), unsafe.Pointer(obj.UnsafeAddr())) +} diff --git a/pkg/state/encode.go b/pkg/state/encode.go new file mode 100644 index 000000000..92fcad4e9 --- /dev/null +++ b/pkg/state/encode.go @@ -0,0 +1,841 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package state + +import ( + "context" + "reflect" + + "gvisor.dev/gvisor/pkg/state/wire" +) + +// objectEncodeState the type and identity of an object occupying a memory +// address range. This is the value type for addrSet, and the intrusive entry +// for the pending and deferred lists. +type objectEncodeState struct { + // id is the assigned ID for this object. + id objectID + + // obj is the object value. Note that this may be replaced if we + // encounter an object that contains this object. When this happens (in + // resolve), we will update existing references approprately, below, + // and defer a re-encoding of the object. + obj reflect.Value + + // encoded is the encoded value of this object. Note that this may not + // be up to date if this object is still in the deferred list. + encoded wire.Object + + // how indicates whether this object should be encoded as a value. This + // is used only for deferred encoding. + how encodeStrategy + + // refs are the list of reference objects used by other objects + // referring to this object. When the object is updated, these + // references may be updated directly and automatically. + refs []*wire.Ref + + pendingEntry + deferredEntry +} + +// encodeState is state used for encoding. +// +// The encoding process constructs a representation of the in-memory graph of +// objects before a single object is serialized. This is done to ensure that +// all references can be fully disambiguated. See resolve for more details. +type encodeState struct { + // ctx is the encode context. + ctx context.Context + + // w is the output stream. + w wire.Writer + + // types is the type database. + types typeEncodeDatabase + + // lastID is the last allocated object ID. + lastID objectID + + // values tracks the address ranges occupied by objects, along with the + // types of these objects. This is used to locate pointer targets, + // including pointers to fields within another type. + // + // Multiple objects may overlap in memory iff the larger object fully + // contains the smaller one, and the type of the smaller object matches + // a field or array element's type at the appropriate offset. An + // arbitrary number of objects may be nested in this manner. + // + // Note that this does not track zero-sized objects, those are tracked + // by zeroValues below. + values addrSet + + // zeroValues tracks zero-sized objects. + zeroValues map[reflect.Type]*objectEncodeState + + // deferred is the list of objects to be encoded. + deferred deferredList + + // pendingTypes is the list of types to be serialized. Serialization + // will occur when all objects have been encoded, but before pending is + // serialized. + pendingTypes []wire.Type + + // pending is the list of objects to be serialized. Serialization does + // not actually occur until the full object graph is computed. + pending pendingList + + // stats tracks time data. + stats Stats +} + +// isSameSizeParent returns true if child is a field value or element within +// parent. Only a struct or array can have a child value. +// +// isSameSizeParent deals with objects like this: +// +// struct child { +// // fields.. +// } +// +// struct parent { +// c child +// } +// +// var p parent +// record(&p.c) +// +// Here, &p and &p.c occupy the exact same address range. +// +// Or like this: +// +// struct child { +// // fields +// } +// +// var arr [1]parent +// record(&arr[0]) +// +// Similarly, &arr[0] and &arr[0].c have the exact same address range. +// +// Precondition: parent and child must occupy the same memory. +func isSameSizeParent(parent reflect.Value, childType reflect.Type) bool { + switch parent.Kind() { + case reflect.Struct: + for i := 0; i < parent.NumField(); i++ { + field := parent.Field(i) + if field.Type() == childType { + return true + } + // Recurse through any intermediate types. + if isSameSizeParent(field, childType) { + return true + } + // Does it make sense to keep going if the first field + // doesn't match? Yes, because there might be an + // arbitrary number of zero-sized fields before we get + // a match, and childType itself can be zero-sized. + } + return false + case reflect.Array: + // The only case where an array with more than one elements can + // return true is if childType is zero-sized. In such cases, + // it's ambiguous which element contains the match since a + // zero-sized child object fully fits in any of the zero-sized + // elements in an array... However since all elements are of + // the same type, we only need to check one element. + // + // For non-zero-sized childTypes, parent.Len() must be 1, but a + // combination of the precondition and an implicit comparison + // between the array element size and childType ensures this. + return parent.Len() > 0 && isSameSizeParent(parent.Index(0), childType) + default: + return false + } +} + +// nextID returns the next valid ID. +func (es *encodeState) nextID() objectID { + es.lastID++ + return objectID(es.lastID) +} + +// dummyAddr points to the dummy zero-sized address. +var dummyAddr = reflect.ValueOf(new(struct{})).Pointer() + +// resolve records the address range occupied by an object. +func (es *encodeState) resolve(obj reflect.Value, ref *wire.Ref) { + addr := obj.Pointer() + + // Is this a map pointer? Just record the single address. It is not + // possible to take any pointers into the map internals. + if obj.Kind() == reflect.Map { + if addr == 0 { + // Just leave the nil reference alone. This is fine, we + // may need to encode as a reference in this way. We + // return nil for our objectEncodeState so that anyone + // depending on this value knows there's nothing there. + return + } + if seg, _ := es.values.Find(addr); seg.Ok() { + // Ensure the map types match. + existing := seg.Value() + if existing.obj.Type() != obj.Type() { + Failf("overlapping map objects at 0x%x: [new object] %#v [existing object type] %s", addr, obj, existing.obj) + } + + // No sense recording refs, maps may not be replaced by + // covering objects, they are maximal. + ref.Root = wire.Uint(existing.id) + return + } + + // Record the map. + oes := &objectEncodeState{ + id: es.nextID(), + obj: obj, + how: encodeMapAsValue, + } + es.values.Add(addrRange{addr, addr + 1}, oes) + es.pending.PushBack(oes) + es.deferred.PushBack(oes) + + // See above: no ref recording. + ref.Root = wire.Uint(oes.id) + return + } + + // If not a map, then the object must be a pointer. + if obj.Kind() != reflect.Ptr { + Failf("attempt to record non-map and non-pointer object %#v", obj) + } + + obj = obj.Elem() // Value from here. + + // Is this a zero-sized type? + typ := obj.Type() + size := typ.Size() + if size == 0 { + if addr == dummyAddr { + // Zero-sized objects point to a dummy byte within the + // runtime. There's no sense recording this in the + // address map. We add this to the dedicated + // zeroValues. + // + // Note that zero-sized objects must be *true* + // zero-sized objects. They cannot be part of some + // larger object. In that case, they are assigned a + // 1-byte address at the end of the object. + oes, ok := es.zeroValues[typ] + if !ok { + oes = &objectEncodeState{ + id: es.nextID(), + obj: obj, + } + es.zeroValues[typ] = oes + es.pending.PushBack(oes) + es.deferred.PushBack(oes) + } + + // There's also no sense tracking back references. We + // know that this is a true zero-sized object, and not + // part of a larger container, so it will not change. + ref.Root = wire.Uint(oes.id) + return + } + size = 1 // See above. + } + + // Calculate the container. + end := addr + size + r := addrRange{addr, end} + if seg, _ := es.values.Find(addr); seg.Ok() { + existing := seg.Value() + switch { + case seg.Start() == addr && seg.End() == end && obj.Type() == existing.obj.Type(): + // The object is a perfect match. Happy path. Avoid the + // traversal and just return directly. We don't need to + // encode the type information or any dots here. + ref.Root = wire.Uint(existing.id) + existing.refs = append(existing.refs, ref) + return + + case (seg.Start() < addr && seg.End() >= end) || (seg.Start() <= addr && seg.End() > end): + // The previously registered object is larger than + // this, no need to update. But we expect some + // traversal below. + + case seg.Start() == addr && seg.End() == end: + if !isSameSizeParent(obj, existing.obj.Type()) { + break // Needs traversal. + } + fallthrough // Needs update. + + case (seg.Start() > addr && seg.End() <= end) || (seg.Start() >= addr && seg.End() < end): + // Update the object and redo the encoding. + old := existing.obj + existing.obj = obj + es.deferred.Remove(existing) + es.deferred.PushBack(existing) + + // The previously registered object is superseded by + // this new object. We are guaranteed to not have any + // mergeable neighbours in this segment set. + if !raceEnabled { + seg.SetRangeUnchecked(r) + } else { + // Add extra paranoid. This will be statically + // removed at compile time unless a race build. + es.values.Remove(seg) + es.values.Add(r, existing) + seg = es.values.LowerBoundSegment(addr) + } + + // Compute the traversal required & update references. + dots := traverse(obj.Type(), old.Type(), addr, seg.Start()) + wt := es.findType(obj.Type()) + for _, ref := range existing.refs { + ref.Dots = append(ref.Dots, dots...) + ref.Type = wt + } + default: + // There is a non-sensical overlap. + Failf("overlapping objects: [new object] %#v [existing object] %#v", obj, existing.obj) + } + + // Compute the new reference, record and return it. + ref.Root = wire.Uint(existing.id) + ref.Dots = traverse(existing.obj.Type(), obj.Type(), seg.Start(), addr) + ref.Type = es.findType(obj.Type()) + existing.refs = append(existing.refs, ref) + return + } + + // The only remaining case is a pointer value that doesn't overlap with + // any registered addresses. Create a new entry for it, and start + // tracking the first reference we just created. + oes := &objectEncodeState{ + id: es.nextID(), + obj: obj, + } + if !raceEnabled { + es.values.AddWithoutMerging(r, oes) + } else { + // Merges should never happen. This is just enabled extra + // sanity checks because the Merge function below will panic. + es.values.Add(r, oes) + } + es.pending.PushBack(oes) + es.deferred.PushBack(oes) + ref.Root = wire.Uint(oes.id) + oes.refs = append(oes.refs, ref) +} + +// traverse searches for a target object within a root object, where the target +// object is a struct field or array element within root, with potentially +// multiple intervening types. traverse returns the set of field or element +// traversals required to reach the target. +// +// Note that for efficiency, traverse returns the dots in the reverse order. +// That is, the first traversal required will be the last element of the list. +// +// Precondition: The target object must lie completely within the range defined +// by [rootAddr, rootAddr + sizeof(rootType)]. +func traverse(rootType, targetType reflect.Type, rootAddr, targetAddr uintptr) []wire.Dot { + // Recursion base case: the types actually match. + if targetType == rootType && targetAddr == rootAddr { + return nil + } + + switch rootType.Kind() { + case reflect.Struct: + offset := targetAddr - rootAddr + for i := rootType.NumField(); i > 0; i-- { + field := rootType.Field(i - 1) + // The first field from the end with an offset that is + // smaller than or equal to our address offset is where + // the target is located. Traverse from there. + if field.Offset <= offset { + dots := traverse(field.Type, targetType, rootAddr+field.Offset, targetAddr) + fieldName := wire.FieldName(field.Name) + return append(dots, &fieldName) + } + } + // Should never happen; the target should be reachable. + Failf("no field in root type %v contains target type %v", rootType, targetType) + + case reflect.Array: + // Since arrays have homogenous types, all elements have the + // same size and we can compute where the target lives. This + // does not matter for the purpose of typing, but matters for + // the purpose of computing the address of the given index. + elemSize := int(rootType.Elem().Size()) + n := int(targetAddr-rootAddr) / elemSize // Relies on integer division rounding down. + if rootType.Len() < n { + Failf("traversal target of type %v @%x is beyond the end of the array type %v @%x with %v elements", + targetType, targetAddr, rootType, rootAddr, rootType.Len()) + } + dots := traverse(rootType.Elem(), targetType, rootAddr+uintptr(n*elemSize), targetAddr) + return append(dots, wire.Index(n)) + + default: + // For any other type, there's no possibility of aliasing so if + // the types didn't match earlier then we have an addresss + // collision which shouldn't be possible at this point. + Failf("traverse failed for root type %v and target type %v", rootType, targetType) + } + panic("unreachable") +} + +// encodeMap encodes a map. +func (es *encodeState) encodeMap(obj reflect.Value, dest *wire.Object) { + if obj.IsNil() { + // Because there is a difference between a nil map and an empty + // map, we need to not decode in the case of a truly nil map. + *dest = wire.Nil{} + return + } + l := obj.Len() + m := &wire.Map{ + Keys: make([]wire.Object, l), + Values: make([]wire.Object, l), + } + *dest = m + for i, k := range obj.MapKeys() { + v := obj.MapIndex(k) + // Map keys must be encoded using the full value because the + // type will be omitted after the first key. + es.encodeObject(k, encodeAsValue, &m.Keys[i]) + es.encodeObject(v, encodeAsValue, &m.Values[i]) + } +} + +// objectEncoder is for encoding structs. +type objectEncoder struct { + // es is encodeState. + es *encodeState + + // encoded is the encoded struct. + encoded *wire.Struct +} + +// save is called by the public methods on Sink. +func (oe *objectEncoder) save(slot int, obj reflect.Value) { + fieldValue := oe.encoded.Field(slot) + oe.es.encodeObject(obj, encodeDefault, fieldValue) +} + +// encodeStruct encodes a composite object. +func (es *encodeState) encodeStruct(obj reflect.Value, dest *wire.Object) { + // Ensure that the obj is addressable. There are two cases when it is + // not. First, is when this is dispatched via SaveValue. Second, when + // this is a map key as a struct. Either way, we need to make a copy to + // obtain an addressable value. + if !obj.CanAddr() { + localObj := reflect.New(obj.Type()) + localObj.Elem().Set(obj) + obj = localObj.Elem() + } + + // Prepare the value. + s := &wire.Struct{} + *dest = s + + // Look the type up in the database. + te, ok := es.types.Lookup(obj.Type()) + if te == nil { + if obj.NumField() == 0 { + // Allow unregistered anonymous, empty structs. This + // will just return success without ever invoking the + // passed function. This uses the immutable EmptyStruct + // variable to prevent an allocation in this case. + // + // Note that this mechanism does *not* work for + // interfaces in general. So you can't dispatch + // non-registered empty structs via interfaces because + // then they can't be restored. + s.Alloc(0) + return + } + // We need a SaverLoader for struct types. + Failf("struct %T does not implement SaverLoader", obj.Interface()) + } + if !ok { + // Queue the type to be serialized. + es.pendingTypes = append(es.pendingTypes, te.Type) + } + + // Invoke the provided saver. + s.TypeID = wire.TypeID(te.ID) + s.Alloc(len(te.Fields)) + oe := objectEncoder{ + es: es, + encoded: s, + } + es.stats.start(te.ID) + defer es.stats.done() + if sl, ok := obj.Addr().Interface().(SaverLoader); ok { + // Note: may be a registered empty struct which does not + // implement the saver/loader interfaces. + sl.StateSave(Sink{internal: oe}) + } +} + +// encodeArray encodes an array. +func (es *encodeState) encodeArray(obj reflect.Value, dest *wire.Object) { + l := obj.Len() + a := &wire.Array{ + Contents: make([]wire.Object, l), + } + *dest = a + for i := 0; i < l; i++ { + // We need to encode the full value because arrays are encoded + // using the type information from only the first element. + es.encodeObject(obj.Index(i), encodeAsValue, &a.Contents[i]) + } +} + +// findType recursively finds type information. +func (es *encodeState) findType(typ reflect.Type) wire.TypeSpec { + // First: check if this is a proper type. It's possible for pointers, + // slices, arrays, maps, etc to all have some different type. + te, ok := es.types.Lookup(typ) + if te != nil { + if !ok { + // See encodeStruct. + es.pendingTypes = append(es.pendingTypes, te.Type) + } + return wire.TypeID(te.ID) + } + + switch typ.Kind() { + case reflect.Ptr: + return &wire.TypeSpecPointer{ + Type: es.findType(typ.Elem()), + } + case reflect.Slice: + return &wire.TypeSpecSlice{ + Type: es.findType(typ.Elem()), + } + case reflect.Array: + return &wire.TypeSpecArray{ + Count: wire.Uint(typ.Len()), + Type: es.findType(typ.Elem()), + } + case reflect.Map: + return &wire.TypeSpecMap{ + Key: es.findType(typ.Key()), + Value: es.findType(typ.Elem()), + } + default: + // After potentially chasing many pointers, the + // ultimate type of the object is not known. + Failf("type %q is not known", typ) + } + panic("unreachable") +} + +// encodeInterface encodes an interface. +func (es *encodeState) encodeInterface(obj reflect.Value, dest *wire.Object) { + // Dereference the object. + obj = obj.Elem() + if !obj.IsValid() { + // Special case: the nil object. + *dest = &wire.Interface{ + Type: wire.TypeSpecNil{}, + Value: wire.Nil{}, + } + return + } + + // Encode underlying object. + i := &wire.Interface{ + Type: es.findType(obj.Type()), + } + *dest = i + es.encodeObject(obj, encodeAsValue, &i.Value) +} + +// isPrimitive returns true if this is a primitive object, or a composite +// object composed entirely of primitives. +func isPrimitiveZero(typ reflect.Type) bool { + switch typ.Kind() { + case reflect.Ptr: + // Pointers are always treated as primitive types because we + // won't encode directly from here. Returning true here won't + // prevent the object from being encoded correctly. + return true + case reflect.Bool: + return true + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + return true + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + return true + case reflect.Float32, reflect.Float64: + return true + case reflect.Complex64, reflect.Complex128: + return true + case reflect.String: + return true + case reflect.Slice: + // The slice itself a primitive, but not necessarily the array + // that points to. This is similar to a pointer. + return true + case reflect.Array: + // We cannot treat an array as a primitive, because it may be + // composed of structures or other things with side-effects. + return isPrimitiveZero(typ.Elem()) + case reflect.Interface: + // Since we now that this type is the zero type, the interface + // value must be zero. Therefore this is primitive. + return true + case reflect.Struct: + return false + case reflect.Map: + // The isPrimitiveZero function is called only on zero-types to + // see if it's safe to serialize. Since a zero map has no + // elements, it is safe to treat as a primitive. + return true + default: + Failf("unknown type %q", typ.Name()) + } + panic("unreachable") +} + +// encodeStrategy is the strategy used for encodeObject. +type encodeStrategy int + +const ( + // encodeDefault means types are encoded normally as references. + encodeDefault encodeStrategy = iota + + // encodeAsValue means that types will never take short-circuited and + // will always be encoded as a normal value. + encodeAsValue + + // encodeMapAsValue means that even maps will be fully encoded. + encodeMapAsValue +) + +// encodeObject encodes an object. +func (es *encodeState) encodeObject(obj reflect.Value, how encodeStrategy, dest *wire.Object) { + if how == encodeDefault && isPrimitiveZero(obj.Type()) && obj.IsZero() { + *dest = wire.Nil{} + return + } + switch obj.Kind() { + case reflect.Ptr: // Fast path: first. + r := new(wire.Ref) + *dest = r + if obj.IsNil() { + // May be in an array or elsewhere such that a value is + // required. So we encode as a reference to the zero + // object, which does not exist. Note that this has to + // be handled correctly in the decode path as well. + return + } + es.resolve(obj, r) + case reflect.Bool: + *dest = wire.Bool(obj.Bool()) + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + *dest = wire.Int(obj.Int()) + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + *dest = wire.Uint(obj.Uint()) + case reflect.Float32: + *dest = wire.Float32(obj.Float()) + case reflect.Float64: + *dest = wire.Float64(obj.Float()) + case reflect.Complex64: + c := wire.Complex64(obj.Complex()) + *dest = &c // Needs alloc. + case reflect.Complex128: + c := wire.Complex128(obj.Complex()) + *dest = &c // Needs alloc. + case reflect.String: + s := wire.String(obj.String()) + *dest = &s // Needs alloc. + case reflect.Array: + es.encodeArray(obj, dest) + case reflect.Slice: + s := &wire.Slice{ + Capacity: wire.Uint(obj.Cap()), + Length: wire.Uint(obj.Len()), + } + *dest = s + // Note that we do need to provide a wire.Slice type here as + // how is not encodeDefault. If this were the case, then it + // would have been caught by the IsZero check above and we + // would have just used wire.Nil{}. + if obj.IsNil() { + return + } + // Slices need pointer resolution. + es.resolve(arrayFromSlice(obj), &s.Ref) + case reflect.Interface: + es.encodeInterface(obj, dest) + case reflect.Struct: + es.encodeStruct(obj, dest) + case reflect.Map: + if how == encodeMapAsValue { + es.encodeMap(obj, dest) + return + } + r := new(wire.Ref) + *dest = r + es.resolve(obj, r) + default: + Failf("unknown object %#v", obj.Interface()) + panic("unreachable") + } +} + +// Save serializes the object graph rooted at obj. +func (es *encodeState) Save(obj reflect.Value) { + es.stats.init() + defer es.stats.fini(func(id typeID) string { + return es.pendingTypes[id-1].Name + }) + + // Resolve the first object, which should queue a pile of additional + // objects on the pending list. All queued objects should be fully + // resolved, and we should be able to serialize after this call. + var root wire.Ref + es.resolve(obj.Addr(), &root) + + // Encode the graph. + var oes *objectEncodeState + if err := safely(func() { + for oes = es.deferred.Front(); oes != nil; oes = es.deferred.Front() { + // Remove and encode the object. Note that as a result + // of this encoding, the object may be enqueued on the + // deferred list yet again. That's expected, and why it + // is removed first. + es.deferred.Remove(oes) + es.encodeObject(oes.obj, oes.how, &oes.encoded) + } + }); err != nil { + // Include the object in the error message. + Failf("encoding error at object %#v: %w", oes.obj.Interface(), err) + } + + // Check that items are pending. + if es.pending.Front() == nil { + Failf("pending is empty?") + } + + // Write the header with the number of objects. Note that there is no + // way that es.lastID could conflict with objectID, which would + // indicate that an impossibly large encoding. + if err := WriteHeader(es.w, uint64(es.lastID), true); err != nil { + Failf("error writing header: %w", err) + } + + // Serialize all pending types and pending objects. Note that we don't + // bother removing from this list as we walk it because that just + // wastes time. It will not change after this point. + var id objectID + if err := safely(func() { + for _, wt := range es.pendingTypes { + // Encode the type. + wire.Save(es.w, &wt) + } + for oes = es.pending.Front(); oes != nil; oes = oes.pendingEntry.Next() { + id++ // First object is 1. + if oes.id != id { + Failf("expected id %d, got %d", id, oes.id) + } + + // Marshall the object. + wire.Save(es.w, oes.encoded) + } + }); err != nil { + // Include the object and the error. + Failf("error serializing object %#v: %w", oes.encoded, err) + } + + // Check what we wrote. + if id != es.lastID { + Failf("expected %d objects, wrote %d", es.lastID, id) + } +} + +// objectFlag indicates that the length is a # of objects, rather than a raw +// byte length. When this is set on a length header in the stream, it may be +// decoded appropriately. +const objectFlag uint64 = 1 << 63 + +// WriteHeader writes a header. +// +// Each object written to the statefile should be prefixed with a header. In +// order to generate statefiles that play nicely with debugging tools, raw +// writes should be prefixed with a header with object set to false and the +// appropriate length. This will allow tools to skip these regions. +func WriteHeader(w wire.Writer, length uint64, object bool) error { + // Sanity check the length. + if length&objectFlag != 0 { + Failf("impossibly huge length: %d", length) + } + if object { + length |= objectFlag + } + + // Write a header. + return safely(func() { + wire.SaveUint(w, length) + }) +} + +// pendingMapper is for the pending list. +type pendingMapper struct{} + +func (pendingMapper) linkerFor(oes *objectEncodeState) *pendingEntry { return &oes.pendingEntry } + +// deferredMapper is for the deferred list. +type deferredMapper struct{} + +func (deferredMapper) linkerFor(oes *objectEncodeState) *deferredEntry { return &oes.deferredEntry } + +// addrSetFunctions is used by addrSet. +type addrSetFunctions struct{} + +func (addrSetFunctions) MinKey() uintptr { + return 0 +} + +func (addrSetFunctions) MaxKey() uintptr { + return ^uintptr(0) +} + +func (addrSetFunctions) ClearValue(val **objectEncodeState) { + *val = nil +} + +func (addrSetFunctions) Merge(r1 addrRange, val1 *objectEncodeState, r2 addrRange, val2 *objectEncodeState) (*objectEncodeState, bool) { + if val1.obj == val2.obj { + // This, should never happen. It would indicate that the same + // object exists in two non-contiguous address ranges. Note + // that this assertion can only be triggered if the race + // detector is enabled. + Failf("unexpected merge in addrSet @ %v and %v: %#v and %#v", r1, r2, val1.obj, val2.obj) + } + // Reject the merge. + return val1, false +} + +func (addrSetFunctions) Split(r addrRange, val *objectEncodeState, _ uintptr) (*objectEncodeState, *objectEncodeState) { + // A split should never happen: we don't remove ranges. + Failf("unexpected split in addrSet @ %v: %#v", r, val.obj) + panic("unreachable") +} diff --git a/pkg/state/encode_unsafe.go b/pkg/state/encode_unsafe.go new file mode 100644 index 000000000..e0dad83b4 --- /dev/null +++ b/pkg/state/encode_unsafe.go @@ -0,0 +1,33 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package state + +import ( + "reflect" + "unsafe" +) + +// arrayFromSlice constructs a new pointer to the slice data. +// +// It would be similar to the following: +// +// x := make([]Foo, l, c) +// a := ([l]Foo*)(unsafe.Pointer(x[0])) +// +func arrayFromSlice(obj reflect.Value) reflect.Value { + return reflect.NewAt( + reflect.ArrayOf(obj.Cap(), obj.Type().Elem()), + unsafe.Pointer(obj.Pointer())) +} diff --git a/pkg/state/pretty/BUILD b/pkg/state/pretty/BUILD new file mode 100644 index 000000000..d053802f7 --- /dev/null +++ b/pkg/state/pretty/BUILD @@ -0,0 +1,13 @@ +load("//tools:defs.bzl", "go_library") + +package(licenses = ["notice"]) + +go_library( + name = "pretty", + srcs = ["pretty.go"], + visibility = ["//:sandbox"], + deps = [ + "//pkg/state", + "//pkg/state/wire", + ], +) diff --git a/pkg/state/pretty/pretty.go b/pkg/state/pretty/pretty.go new file mode 100644 index 000000000..cf37aaa49 --- /dev/null +++ b/pkg/state/pretty/pretty.go @@ -0,0 +1,273 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package pretty is a pretty-printer for state streams. +package pretty + +import ( + "fmt" + "io" + "io/ioutil" + "reflect" + "strings" + + "gvisor.dev/gvisor/pkg/state" + "gvisor.dev/gvisor/pkg/state/wire" +) + +func formatRef(x *wire.Ref, graph uint64, html bool) string { + baseRef := fmt.Sprintf("g%dr%d", graph, x.Root) + fullRef := baseRef + if len(x.Dots) > 0 { + // See wire.Ref; Type valid if Dots non-zero. + typ, _ := formatType(x.Type, graph, html) + var buf strings.Builder + buf.WriteString("(*") + buf.WriteString(typ) + buf.WriteString(")(") + buf.WriteString(baseRef) + for _, component := range x.Dots { + switch v := component.(type) { + case *wire.FieldName: + buf.WriteString(".") + buf.WriteString(string(*v)) + case wire.Index: + buf.WriteString(fmt.Sprintf("[%d]", v)) + default: + panic(fmt.Sprintf("unreachable: switch should be exhaustive, unhandled case %v", reflect.TypeOf(component))) + } + } + buf.WriteString(")") + fullRef = buf.String() + } + if html { + return fmt.Sprintf("<a href=\"#%s\">%s</a>", baseRef, fullRef) + } + return fullRef +} + +func formatType(t wire.TypeSpec, graph uint64, html bool) (string, bool) { + switch x := t.(type) { + case wire.TypeID: + base := fmt.Sprintf("g%dt%d", graph, x) + if html { + return fmt.Sprintf("<a href=\"#%s\">%s</a>", base, base), true + } + return fmt.Sprintf("%s", base), true + case wire.TypeSpecNil: + return "", false // Only nil type. + case *wire.TypeSpecPointer: + element, _ := formatType(x.Type, graph, html) + return fmt.Sprintf("(*%s)", element), true + case *wire.TypeSpecArray: + element, _ := formatType(x.Type, graph, html) + return fmt.Sprintf("[%d](%s)", x.Count, element), true + case *wire.TypeSpecSlice: + element, _ := formatType(x.Type, graph, html) + return fmt.Sprintf("([]%s)", element), true + case *wire.TypeSpecMap: + key, _ := formatType(x.Key, graph, html) + value, _ := formatType(x.Value, graph, html) + return fmt.Sprintf("(map[%s]%s)", key, value), true + default: + panic(fmt.Sprintf("unreachable: unknown type %T", t)) + } +} + +// format formats a single object, for pretty-printing. It also returns whether +// the value is a non-zero value. +func format(graph uint64, depth int, encoded wire.Object, html bool) (string, bool) { + switch x := encoded.(type) { + case wire.Nil: + return "nil", false + case *wire.String: + return fmt.Sprintf("%q", *x), *x != "" + case *wire.Complex64: + return fmt.Sprintf("%f+%fi", real(*x), imag(*x)), *x != 0.0 + case *wire.Complex128: + return fmt.Sprintf("%f+%fi", real(*x), imag(*x)), *x != 0.0 + case *wire.Ref: + return formatRef(x, graph, html), x.Root != 0 + case *wire.Type: + tabs := "\n" + strings.Repeat("\t", depth) + items := make([]string, 0, len(x.Fields)+2) + items = append(items, fmt.Sprintf("type %s {", x.Name)) + for i := 0; i < len(x.Fields); i++ { + items = append(items, fmt.Sprintf("\t%d: %s,", i, x.Fields[i])) + } + items = append(items, "}") + return strings.Join(items, tabs), true // No zero value. + case *wire.Slice: + return fmt.Sprintf("%s{len:%d,cap:%d}", formatRef(&x.Ref, graph, html), x.Length, x.Capacity), x.Capacity != 0 + case *wire.Array: + if len(x.Contents) == 0 { + return "[]", false + } + items := make([]string, 0, len(x.Contents)+2) + zeros := make([]string, 0) // used to eliminate zero entries. + items = append(items, "[") + tabs := "\n" + strings.Repeat("\t", depth) + for i := 0; i < len(x.Contents); i++ { + item, ok := format(graph, depth+1, x.Contents[i], html) + if !ok { + zeros = append(zeros, fmt.Sprintf("\t%s,", item)) + continue + } + if len(zeros) > 0 { + items = append(items, zeros...) + zeros = nil + } + items = append(items, fmt.Sprintf("\t%s,", item)) + } + if len(zeros) > 0 { + items = append(items, fmt.Sprintf("\t... (%d zeros),", len(zeros))) + } + items = append(items, "]") + return strings.Join(items, tabs), len(zeros) < len(x.Contents) + case *wire.Struct: + typ, _ := formatType(x.TypeID, graph, html) + if x.Fields() == 0 { + return fmt.Sprintf("struct[%s]{}", typ), false + } + items := make([]string, 0, 2) + items = append(items, fmt.Sprintf("struct[%s]{", typ)) + tabs := "\n" + strings.Repeat("\t", depth) + allZero := true + for i := 0; i < x.Fields(); i++ { + element, ok := format(graph, depth+1, *x.Field(i), html) + allZero = allZero && !ok + items = append(items, fmt.Sprintf("\t%d: %s,", i, element)) + i++ + } + items = append(items, "}") + return strings.Join(items, tabs), !allZero + case *wire.Map: + if len(x.Keys) == 0 { + return "map{}", false + } + items := make([]string, 0, len(x.Keys)+2) + items = append(items, "map{") + tabs := "\n" + strings.Repeat("\t", depth) + for i := 0; i < len(x.Keys); i++ { + key, _ := format(graph, depth+1, x.Keys[i], html) + value, _ := format(graph, depth+1, x.Values[i], html) + items = append(items, fmt.Sprintf("\t%s: %s,", key, value)) + } + items = append(items, "}") + return strings.Join(items, tabs), true + case *wire.Interface: + typ, typOk := formatType(x.Type, graph, html) + element, elementOk := format(graph, depth+1, x.Value, html) + return fmt.Sprintf("interface[%s]{%s}", typ, element), typOk || elementOk + default: + // Must be a primitive; use reflection. + return fmt.Sprintf("%v", encoded), true + } +} + +// printStream is the basic print implementation. +func printStream(w io.Writer, r wire.Reader, html bool) (err error) { + // current graph ID. + var graph uint64 + + if html { + fmt.Fprintf(w, "<pre>") + defer fmt.Fprintf(w, "</pre>") + } + + defer func() { + if r := recover(); r != nil { + if rErr, ok := r.(error); ok { + err = rErr // Override return. + return + } + panic(r) // Propagate. + } + }() + + for { + // Find the first object to begin generation. + length, object, err := state.ReadHeader(r) + if err == io.EOF { + // Nothing else to do. + break + } else if err != nil { + return err + } + if !object { + graph++ // Increment the graph. + if length > 0 { + fmt.Fprintf(w, "(%d bytes non-object data)\n", length) + io.Copy(ioutil.Discard, &io.LimitedReader{ + R: r, + N: int64(length), + }) + } + continue + } + + // Read & unmarshal the object. + // + // Note that this loop must match the general structure of the + // loop in decode.go. But we don't register type information, + // etc. and just print the raw structures. + var ( + oid uint64 = 1 + tid uint64 = 1 + ) + for oid <= length { + // Unmarshal the object. + encoded := wire.Load(r) + + // Is this a type? + if _, ok := encoded.(*wire.Type); ok { + str, _ := format(graph, 0, encoded, html) + tag := fmt.Sprintf("g%dt%d", graph, tid) + if html { + // See below. + tag = fmt.Sprintf("<a name=\"%s\">%s</a><a href=\"#%s\">⚓</a>", tag, tag, tag) + } + if _, err := fmt.Fprintf(w, "%s = %s\n", tag, str); err != nil { + return err + } + tid++ + continue + } + + // Format the node. + str, _ := format(graph, 0, encoded, html) + tag := fmt.Sprintf("g%dr%d", graph, oid) + if html { + // Create a little tag with an anchor next to it for linking. + tag = fmt.Sprintf("<a name=\"%s\">%s</a><a href=\"#%s\">⚓</a>", tag, tag, tag) + } + if _, err := fmt.Fprintf(w, "%s = %s\n", tag, str); err != nil { + return err + } + oid++ + } + } + + return nil +} + +// PrintText reads the stream from r and prints text to w. +func PrintText(w io.Writer, r wire.Reader) error { + return printStream(w, r, false /* html */) +} + +// PrintHTML reads the stream from r and prints html to w. +func PrintHTML(w io.Writer, r wire.Reader) error { + return printStream(w, r, true /* html */) +} diff --git a/pkg/state/state.go b/pkg/state/state.go new file mode 100644 index 000000000..acb629969 --- /dev/null +++ b/pkg/state/state.go @@ -0,0 +1,321 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package state provides functionality related to saving and loading object +// graphs. For most types, it provides a set of default saving / loading logic +// that will be invoked automatically if custom logic is not defined. +// +// Kind Support +// ---- ------- +// Bool default +// Int default +// Int8 default +// Int16 default +// Int32 default +// Int64 default +// Uint default +// Uint8 default +// Uint16 default +// Uint32 default +// Uint64 default +// Float32 default +// Float64 default +// Complex64 default +// Complex128 default +// Array default +// Chan custom +// Func custom +// Interface default +// Map default +// Ptr default +// Slice default +// String default +// Struct custom (*) Unless zero-sized. +// UnsafePointer custom +// +// See README.md for an overview of how encoding and decoding works. +package state + +import ( + "context" + "fmt" + "reflect" + "runtime" + + "gvisor.dev/gvisor/pkg/state/wire" +) + +// objectID is a unique identifier assigned to each object to be serialized. +// Each instance of an object is considered separately, i.e. if there are two +// objects of the same type in the object graph being serialized, they'll be +// assigned unique objectIDs. +type objectID uint32 + +// typeID is the identifier for a type. Types are serialized and tracked +// alongside objects in order to avoid the overhead of encoding field names in +// all objects. +type typeID uint32 + +// ErrState is returned when an error is encountered during encode/decode. +type ErrState struct { + // err is the underlying error. + err error + + // trace is the stack trace. + trace string +} + +// Error returns a sensible description of the state error. +func (e *ErrState) Error() string { + return fmt.Sprintf("%v:\n%s", e.err, e.trace) +} + +// Unwrap implements standard unwrapping. +func (e *ErrState) Unwrap() error { + return e.err +} + +// Save saves the given object state. +func Save(ctx context.Context, w wire.Writer, rootPtr interface{}) (Stats, error) { + // Create the encoding state. + es := encodeState{ + ctx: ctx, + w: w, + types: makeTypeEncodeDatabase(), + zeroValues: make(map[reflect.Type]*objectEncodeState), + } + + // Perform the encoding. + err := safely(func() { + es.Save(reflect.ValueOf(rootPtr).Elem()) + }) + return es.stats, err +} + +// Load loads a checkpoint. +func Load(ctx context.Context, r wire.Reader, rootPtr interface{}) (Stats, error) { + // Create the decoding state. + ds := decodeState{ + ctx: ctx, + r: r, + types: makeTypeDecodeDatabase(), + deferred: make(map[objectID]wire.Object), + } + + // Attempt our decode. + err := safely(func() { + ds.Load(reflect.ValueOf(rootPtr).Elem()) + }) + return ds.stats, err +} + +// Sink is used for Type.StateSave. +type Sink struct { + internal objectEncoder +} + +// Save adds the given object to the map. +// +// You should pass always pointers to the object you are saving. For example: +// +// type X struct { +// A int +// B *int +// } +// +// func (x *X) StateTypeInfo(m Sink) state.TypeInfo { +// return state.TypeInfo{ +// Name: "pkg.X", +// Fields: []string{ +// "A", +// "B", +// }, +// } +// } +// +// func (x *X) StateSave(m Sink) { +// m.Save(0, &x.A) // Field is A. +// m.Save(1, &x.B) // Field is B. +// } +// +// func (x *X) StateLoad(m Source) { +// m.Load(0, &x.A) // Field is A. +// m.Load(1, &x.B) // Field is B. +// } +func (s Sink) Save(slot int, objPtr interface{}) { + s.internal.save(slot, reflect.ValueOf(objPtr).Elem()) +} + +// SaveValue adds the given object value to the map. +// +// This should be used for values where pointers are not available, or casts +// are required during Save/Load. +// +// For example, if we want to cast external package type P.Foo to int64: +// +// func (x *X) StateSave(m Sink) { +// m.SaveValue(0, "A", int64(x.A)) +// } +// +// func (x *X) StateLoad(m Source) { +// m.LoadValue(0, new(int64), func(x interface{}) { +// x.A = P.Foo(x.(int64)) +// }) +// } +func (s Sink) SaveValue(slot int, obj interface{}) { + s.internal.save(slot, reflect.ValueOf(obj)) +} + +// Context returns the context object provided at save time. +func (s Sink) Context() context.Context { + return s.internal.es.ctx +} + +// Type is an interface that must be implemented by Struct objects. This allows +// these objects to be serialized while minimizing runtime reflection required. +// +// All these methods can be automatically generated by the go_statify tool. +type Type interface { + // StateTypeName returns the type's name. + // + // This is used for matching type information during encoding and + // decoding, as well as dynamic interface dispatch. This should be + // globally unique. + StateTypeName() string + + // StateFields returns information about the type. + // + // Fields is the set of fields for the object. Calls to Sink.Save and + // Source.Load must be made in-order with respect to these fields. + // + // This will be called at most once per serialization. + StateFields() []string +} + +// SaverLoader must be implemented by struct types. +type SaverLoader interface { + // StateSave saves the state of the object to the given Map. + StateSave(Sink) + + // StateLoad loads the state of the object. + StateLoad(Source) +} + +// Source is used for Type.StateLoad. +type Source struct { + internal objectDecoder +} + +// Load loads the given object passed as a pointer.. +// +// See Sink.Save for an example. +func (s Source) Load(slot int, objPtr interface{}) { + s.internal.load(slot, reflect.ValueOf(objPtr), false, nil) +} + +// LoadWait loads the given objects from the map, and marks it as requiring all +// AfterLoad executions to complete prior to running this object's AfterLoad. +// +// See Sink.Save for an example. +func (s Source) LoadWait(slot int, objPtr interface{}) { + s.internal.load(slot, reflect.ValueOf(objPtr), true, nil) +} + +// LoadValue loads the given object value from the map. +// +// See Sink.SaveValue for an example. +func (s Source) LoadValue(slot int, objPtr interface{}, fn func(interface{})) { + o := reflect.ValueOf(objPtr) + s.internal.load(slot, o, true, func() { fn(o.Elem().Interface()) }) +} + +// AfterLoad schedules a function execution when all objects have been +// allocated and their automated loading and customized load logic have been +// executed. fn will not be executed until all of current object's +// dependencies' AfterLoad() logic, if exist, have been executed. +func (s Source) AfterLoad(fn func()) { + s.internal.afterLoad(fn) +} + +// Context returns the context object provided at load time. +func (s Source) Context() context.Context { + return s.internal.ds.ctx +} + +// IsZeroValue checks if the given value is the zero value. +// +// This function is used by the stateify tool. +func IsZeroValue(val interface{}) bool { + return val == nil || reflect.ValueOf(val).Elem().IsZero() +} + +// Failf is a wrapper around panic that should be used to generate errors that +// can be caught during saving and loading. +func Failf(fmtStr string, v ...interface{}) { + panic(fmt.Errorf(fmtStr, v...)) +} + +// safely executes the given function, catching a panic and unpacking as an +// error. +// +// The error flow through the state package uses panic and recover. There are +// two important reasons for this: +// +// 1) Many of the reflection methods will already panic with invalid data or +// violated assumptions. We would want to recover anyways here. +// +// 2) It allows us to eliminate boilerplate within Save() and Load() functions. +// In nearly all cases, when the low-level serialization functions fail, you +// will want the checkpoint to fail anyways. Plumbing errors through every +// method doesn't add a lot of value. If there are specific error conditions +// that you'd like to handle, you should add appropriate functionality to +// objects themselves prior to calling Save() and Load(). +func safely(fn func()) (err error) { + defer func() { + if r := recover(); r != nil { + if es, ok := r.(*ErrState); ok { + err = es // Propagate. + return + } + + // Build a new state error. + es := new(ErrState) + if e, ok := r.(error); ok { + es.err = e + } else { + es.err = fmt.Errorf("%v", r) + } + + // Make a stack. We don't know how big it will be ahead + // of time, but want to make sure we get the whole + // thing. So we just do a stupid brute force approach. + var stack []byte + for sz := 1024; ; sz *= 2 { + stack = make([]byte, sz) + n := runtime.Stack(stack, false) + if n < sz { + es.trace = string(stack[:n]) + break + } + } + + // Set the error. + err = es + } + }() + + // Execute the function. + fn() + return nil +} diff --git a/pkg/state/state_norace.go b/pkg/state/state_norace.go new file mode 100644 index 000000000..4281aed6d --- /dev/null +++ b/pkg/state/state_norace.go @@ -0,0 +1,19 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build !race + +package state + +var raceEnabled = false diff --git a/pkg/state/state_race.go b/pkg/state/state_race.go new file mode 100644 index 000000000..8232981ce --- /dev/null +++ b/pkg/state/state_race.go @@ -0,0 +1,19 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build race + +package state + +var raceEnabled = true diff --git a/pkg/state/statefile/BUILD b/pkg/state/statefile/BUILD new file mode 100644 index 000000000..d6c89c7e9 --- /dev/null +++ b/pkg/state/statefile/BUILD @@ -0,0 +1,22 @@ +load("//tools:defs.bzl", "go_library", "go_test") + +package(licenses = ["notice"]) + +go_library( + name = "statefile", + srcs = ["statefile.go"], + visibility = ["//:sandbox"], + deps = [ + "//pkg/binary", + "//pkg/compressio", + "//pkg/state/wire", + ], +) + +go_test( + name = "statefile_test", + size = "small", + srcs = ["statefile_test.go"], + library = ":statefile", + deps = ["//pkg/compressio"], +) diff --git a/pkg/state/statefile/statefile.go b/pkg/state/statefile/statefile.go new file mode 100644 index 000000000..bdfb800fb --- /dev/null +++ b/pkg/state/statefile/statefile.go @@ -0,0 +1,239 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package statefile defines the state file data stream. +// +// This package currently does not include any details regarding the state +// encoding itself, only details regarding state metadata and data layout. +// +// The file format is defined as follows. +// +// /------------------------------------------------------\ +// | header (8-bytes) | +// +------------------------------------------------------+ +// | metadata length (8-bytes) | +// +------------------------------------------------------+ +// | metadata | +// +------------------------------------------------------+ +// | data | +// \------------------------------------------------------/ +// +// First, it includes a 8-byte magic header which is the following +// sequence of bytes [0x67, 0x56, 0x69, 0x73, 0x6f, 0x72, 0x53, 0x46] +// +// This header is followed by an 8-byte length N (big endian), and an +// ASCII-encoded JSON map that is exactly N bytes long. +// +// This map includes only strings for keys and strings for values. Keys in the +// map that begin with "_" are for internal use only. They may be read, but may +// not be provided by the user. In the future, this metadata may contain some +// information relating to the state encoding itself. +// +// After the map, the remainder of the file is the state data. +package statefile + +import ( + "bytes" + "compress/flate" + "crypto/hmac" + "crypto/sha256" + "encoding/json" + "fmt" + "hash" + "io" + "strings" + "time" + + "gvisor.dev/gvisor/pkg/binary" + "gvisor.dev/gvisor/pkg/compressio" + "gvisor.dev/gvisor/pkg/state/wire" +) + +// keySize is the AES-256 key length. +const keySize = 32 + +// compressionChunkSize is the chunk size for compression. +const compressionChunkSize = 1024 * 1024 + +// maxMetadataSize is the size limit of metadata section. +const maxMetadataSize = 16 * 1024 * 1024 + +// magicHeader is the byte sequence beginning each file. +var magicHeader = []byte("\x67\x56\x69\x73\x6f\x72\x53\x46") + +// ErrBadMagic is returned if the header does not match. +var ErrBadMagic = fmt.Errorf("bad magic header") + +// ErrMetadataMissing is returned if the state file is missing mandatory metadata. +var ErrMetadataMissing = fmt.Errorf("missing metadata") + +// ErrInvalidMetadataLength is returned if the metadata length is too large. +var ErrInvalidMetadataLength = fmt.Errorf("metadata length invalid, maximum size is %d", maxMetadataSize) + +// ErrMetadataInvalid is returned if passed metadata is invalid. +var ErrMetadataInvalid = fmt.Errorf("metadata invalid, can't start with _") + +// WriteCloser is an io.Closer and wire.Writer. +type WriteCloser interface { + wire.Writer + io.Closer +} + +// NewWriter returns a state data writer for a statefile. +// +// Note that the returned WriteCloser must be closed. +func NewWriter(w io.Writer, key []byte, metadata map[string]string) (WriteCloser, error) { + if metadata == nil { + metadata = make(map[string]string) + } + for k := range metadata { + if strings.HasPrefix(k, "_") { + return nil, ErrMetadataInvalid + } + } + + // Create our HMAC function. + h := hmac.New(sha256.New, key) + mw := io.MultiWriter(w, h) + + // First, write the header. + if _, err := mw.Write(magicHeader); err != nil { + return nil, err + } + + // Generate a timestamp, for convenience only. + metadata["_timestamp"] = time.Now().UTC().String() + defer delete(metadata, "_timestamp") + + // Write the metadata. + b, err := json.Marshal(metadata) + if err != nil { + return nil, err + } + + if len(b) > maxMetadataSize { + return nil, ErrInvalidMetadataLength + } + + // Metadata length. + if err := binary.WriteUint64(mw, binary.BigEndian, uint64(len(b))); err != nil { + return nil, err + } + // Metadata bytes; io.MultiWriter will return a short write error if + // any of the writers returns < n. + if _, err := mw.Write(b); err != nil { + return nil, err + } + // Write the current hash. + cur := h.Sum(nil) + for done := 0; done < len(cur); { + n, err := mw.Write(cur[done:]) + done += n + if err != nil { + return nil, err + } + } + + // Wrap in compression. We always use "best speed" mode here. When using + // "best compression" mode, there is usually only a little gain in file + // size reduction, which translate to even smaller gain in restore + // latency reduction, while inccuring much more CPU usage at save time. + return compressio.NewWriter(w, key, compressionChunkSize, flate.BestSpeed) +} + +// MetadataUnsafe reads out the metadata from a state file without verifying any +// HMAC. This function shouldn't be called for untrusted input files. +func MetadataUnsafe(r io.Reader) (map[string]string, error) { + return metadata(r, nil) +} + +// metadata validates the magic header and reads out the metadata from a state +// data stream. +func metadata(r io.Reader, h hash.Hash) (map[string]string, error) { + if h != nil { + r = io.TeeReader(r, h) + } + + // Read and validate magic header. + b := make([]byte, len(magicHeader)) + if _, err := r.Read(b); err != nil { + return nil, err + } + if !bytes.Equal(b, magicHeader) { + return nil, ErrBadMagic + } + + // Read and validate metadata. + b, err := func() (b []byte, err error) { + defer func() { + if r := recover(); r != nil { + b = nil + err = fmt.Errorf("%v", r) + } + }() + + metadataLen, err := binary.ReadUint64(r, binary.BigEndian) + if err != nil { + return nil, err + } + if metadataLen > maxMetadataSize { + return nil, ErrInvalidMetadataLength + } + b = make([]byte, int(metadataLen)) + if _, err := io.ReadFull(r, b); err != nil { + return nil, err + } + return b, nil + }() + if err != nil { + return nil, err + } + + if h != nil { + // Check the hash prior to decoding. + cur := h.Sum(nil) + buf := make([]byte, len(cur)) + if _, err := io.ReadFull(r, buf); err != nil { + return nil, err + } + if !hmac.Equal(cur, buf) { + return nil, compressio.ErrHashMismatch + } + } + + // Decode the metadata. + metadata := make(map[string]string) + if err := json.Unmarshal(b, &metadata); err != nil { + return nil, err + } + + return metadata, nil +} + +// NewReader returns a reader for a statefile. +func NewReader(r io.Reader, key []byte) (wire.Reader, map[string]string, error) { + // Read the metadata with the hash. + h := hmac.New(sha256.New, key) + metadata, err := metadata(r, h) + if err != nil { + return nil, nil, err + } + + // Wrap in compression. + cr, err := compressio.NewReader(r, key) + if err != nil { + return nil, nil, err + } + return cr, metadata, nil +} diff --git a/pkg/state/statefile/statefile_test.go b/pkg/state/statefile/statefile_test.go new file mode 100644 index 000000000..0b470fdec --- /dev/null +++ b/pkg/state/statefile/statefile_test.go @@ -0,0 +1,290 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package statefile + +import ( + "bytes" + crand "crypto/rand" + "encoding/base64" + "io" + "math/rand" + "runtime" + "testing" + "time" + + "gvisor.dev/gvisor/pkg/compressio" +) + +func randomKey() ([]byte, error) { + r := make([]byte, base64.RawStdEncoding.DecodedLen(keySize)) + if _, err := io.ReadFull(crand.Reader, r); err != nil { + return nil, err + } + key := make([]byte, keySize) + base64.RawStdEncoding.Encode(key, r) + return key, nil +} + +type testCase struct { + name string + data []byte + metadata map[string]string +} + +func TestStatefile(t *testing.T) { + rand.Seed(time.Now().Unix()) + + cases := []testCase{ + // Various data sizes. + {"nil", nil, nil}, + {"empty", []byte(""), nil}, + {"some", []byte("_"), nil}, + {"one", []byte("0"), nil}, + {"two", []byte("01"), nil}, + {"three", []byte("012"), nil}, + {"four", []byte("0123"), nil}, + {"five", []byte("01234"), nil}, + {"six", []byte("012356"), nil}, + {"seven", []byte("0123567"), nil}, + {"eight", []byte("01235678"), nil}, + + // Make sure we have one longer than the hash length. + {"longer than hash", []byte("012356asdjflkasjlk3jlk23j4lkjaso0d789f0aujw3lkjlkxsdf78asdful2kj3ljka78"), nil}, + + // Make sure we have one longer than the chunk size. + {"chunks", make([]byte, 3*compressionChunkSize), nil}, + {"large", make([]byte, 30*compressionChunkSize), nil}, + + // Different metadata. + {"one metadata", []byte("data"), map[string]string{"foo": "bar"}}, + {"two metadata", []byte("data"), map[string]string{"foo": "bar", "one": "two"}}, + } + + for _, c := range cases { + // Generate a key. + integrityKey, err := randomKey() + if err != nil { + t.Errorf("can't generate key: got %v, excepted nil", err) + continue + } + + t.Run(c.name, func(t *testing.T) { + for _, key := range [][]byte{nil, integrityKey} { + t.Run("key="+string(key), func(t *testing.T) { + // Encoding happens via a buffer. + var bufEncoded bytes.Buffer + var bufDecoded bytes.Buffer + + // Do all the writing. + w, err := NewWriter(&bufEncoded, key, c.metadata) + if err != nil { + t.Fatalf("error creating writer: got %v, expected nil", err) + } + if _, err := io.Copy(w, bytes.NewBuffer(c.data)); err != nil { + t.Fatalf("error during write: got %v, expected nil", err) + } + + // Finish the sum. + if err := w.Close(); err != nil { + t.Fatalf("error during close: got %v, expected nil", err) + } + + t.Logf("original data: %d bytes, encoded: %d bytes.", + len(c.data), len(bufEncoded.Bytes())) + + // Do all the reading. + r, metadata, err := NewReader(bytes.NewReader(bufEncoded.Bytes()), key) + if err != nil { + t.Fatalf("error creating reader: got %v, expected nil", err) + } + if _, err := io.Copy(&bufDecoded, r); err != nil { + t.Fatalf("error during read: got %v, expected nil", err) + } + + // Check that the data matches. + if !bytes.Equal(c.data, bufDecoded.Bytes()) { + t.Fatalf("data didn't match (%d vs %d bytes)", len(bufDecoded.Bytes()), len(c.data)) + } + + // Check that the metadata matches. + for k, v := range c.metadata { + nv, ok := metadata[k] + if !ok { + t.Fatalf("missing metadata: %s", k) + } + if v != nv { + t.Fatalf("mismatched metdata for %s: got %s, expected %s", k, nv, v) + } + } + + // Change the data and verify that it fails. + if key != nil { + b := append([]byte(nil), bufEncoded.Bytes()...) + b[rand.Intn(len(b))]++ + bufDecoded.Reset() + r, _, err = NewReader(bytes.NewReader(b), key) + if err == nil { + _, err = io.Copy(&bufDecoded, r) + } + if err == nil { + t.Error("got no error: expected error on data corruption") + } + } + + // Change the key and verify that it fails. + newKey := integrityKey + if len(key) > 0 { + newKey = append([]byte{}, key...) + newKey[rand.Intn(len(newKey))]++ + } + bufDecoded.Reset() + r, _, err = NewReader(bytes.NewReader(bufEncoded.Bytes()), newKey) + if err == nil { + _, err = io.Copy(&bufDecoded, r) + } + if err != compressio.ErrHashMismatch { + t.Errorf("got error: %v, expected ErrHashMismatch on key mismatch", err) + } + }) + } + }) + } +} + +const benchmarkDataSize = 100 * 1024 * 1024 + +func benchmark(b *testing.B, size int, write bool, compressible bool) { + b.StopTimer() + b.SetBytes(benchmarkDataSize) + + // Generate source data. + var source []byte + if compressible { + // For compressible data, we use essentially all zeros. + source = make([]byte, benchmarkDataSize) + } else { + // For non-compressible data, we use random base64 data (to + // make it marginally compressible, a ratio of 75%). + var sourceBuf bytes.Buffer + bufW := base64.NewEncoder(base64.RawStdEncoding, &sourceBuf) + bufR := rand.New(rand.NewSource(0)) + if _, err := io.CopyN(bufW, bufR, benchmarkDataSize); err != nil { + b.Fatalf("unable to seed random data: %v", err) + } + source = sourceBuf.Bytes() + } + + // Generate a random key for integrity check. + key, err := randomKey() + if err != nil { + b.Fatalf("error generating key: %v", err) + } + + // Define our benchmark functions. Prior to running the readState + // function here, you must execute the writeState function at least + // once (done below). + var stateBuf bytes.Buffer + writeState := func() { + stateBuf.Reset() + w, err := NewWriter(&stateBuf, key, nil) + if err != nil { + b.Fatalf("error creating writer: %v", err) + } + for done := 0; done < len(source); { + chunk := size // limit size. + if done+chunk > len(source) { + chunk = len(source) - done + } + n, err := w.Write(source[done : done+chunk]) + done += n + if n == 0 && err != nil { + b.Fatalf("error during write: %v", err) + } + } + if err := w.Close(); err != nil { + b.Fatalf("error closing writer: %v", err) + } + } + readState := func() { + tmpBuf := bytes.NewBuffer(stateBuf.Bytes()) + r, _, err := NewReader(tmpBuf, key) + if err != nil { + b.Fatalf("error creating reader: %v", err) + } + for done := 0; done < len(source); { + chunk := size // limit size. + if done+chunk > len(source) { + chunk = len(source) - done + } + n, err := r.Read(source[done : done+chunk]) + done += n + if n == 0 && err != nil { + b.Fatalf("error during read: %v", err) + } + } + } + // Generate the state once without timing to ensure that buffers have + // been appropriately allocated. + writeState() + if write { + b.StartTimer() + for i := 0; i < b.N; i++ { + writeState() + } + b.StopTimer() + } else { + b.StartTimer() + for i := 0; i < b.N; i++ { + readState() + } + b.StopTimer() + } +} + +func BenchmarkWrite4KCompressible(b *testing.B) { + benchmark(b, 4096, true, true) +} + +func BenchmarkWrite4KNoncompressible(b *testing.B) { + benchmark(b, 4096, true, false) +} + +func BenchmarkWrite1MCompressible(b *testing.B) { + benchmark(b, 1024*1024, true, true) +} + +func BenchmarkWrite1MNoncompressible(b *testing.B) { + benchmark(b, 1024*1024, true, false) +} + +func BenchmarkRead4KCompressible(b *testing.B) { + benchmark(b, 4096, false, true) +} + +func BenchmarkRead4KNoncompressible(b *testing.B) { + benchmark(b, 4096, false, false) +} + +func BenchmarkRead1MCompressible(b *testing.B) { + benchmark(b, 1024*1024, false, true) +} + +func BenchmarkRead1MNoncompressible(b *testing.B) { + benchmark(b, 1024*1024, false, false) +} + +func init() { + runtime.GOMAXPROCS(runtime.NumCPU()) +} diff --git a/pkg/state/stats.go b/pkg/state/stats.go new file mode 100644 index 000000000..eaec664a1 --- /dev/null +++ b/pkg/state/stats.go @@ -0,0 +1,145 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package state + +import ( + "bytes" + "fmt" + "sort" + "time" +) + +type statEntry struct { + count uint + total time.Duration +} + +// Stats tracks encode / decode timing. +// +// This currently provides a meaningful String function and no other way to +// extract stats about individual types. +// +// All exported receivers accept nil. +type Stats struct { + // byType contains a breakdown of time spent by type. + // + // This is indexed *directly* by typeID, including zero. + byType []statEntry + + // stack contains objects in progress. + stack []typeID + + // names contains type names. + // + // This is also indexed *directly* by typeID, including zero, which we + // hard-code as "state.default". This is only resolved by calling fini + // on the stats object. + names []string + + // last is the last start time. + last time.Time +} + +// init initializes statistics. +func (s *Stats) init() { + s.last = time.Now() + s.stack = append(s.stack, 0) +} + +// fini finalizes statistics. +func (s *Stats) fini(resolve func(id typeID) string) { + s.done() + + // Resolve all type names. + s.names = make([]string, len(s.byType)) + s.names[0] = "state.default" // See above. + for id := typeID(1); int(id) < len(s.names); id++ { + s.names[id] = resolve(id) + } +} + +// sample adds the samples to the given object. +func (s *Stats) sample(id typeID) { + now := time.Now() + if len(s.byType) <= int(id) { + // Allocate all the missing entries in one fell swoop. + s.byType = append(s.byType, make([]statEntry, 1+int(id)-len(s.byType))...) + } + s.byType[id].total += now.Sub(s.last) + s.last = now +} + +// start starts a sample. +func (s *Stats) start(id typeID) { + last := s.stack[len(s.stack)-1] + s.sample(last) + s.stack = append(s.stack, id) +} + +// done finishes the current sample. +func (s *Stats) done() { + last := s.stack[len(s.stack)-1] + s.sample(last) + s.byType[last].count++ + s.stack = s.stack[:len(s.stack)-1] +} + +type sliceEntry struct { + name string + entry *statEntry +} + +// String returns a table representation of the stats. +func (s *Stats) String() string { + // Build a list of stat entries. + ss := make([]sliceEntry, 0, len(s.byType)) + for id := 0; id < len(s.names); id++ { + ss = append(ss, sliceEntry{ + name: s.names[id], + entry: &s.byType[id], + }) + } + + // Sort by total time (descending). + sort.Slice(ss, func(i, j int) bool { + return ss[i].entry.total > ss[j].entry.total + }) + + // Print the stat results. + var ( + buf bytes.Buffer + count uint + total time.Duration + ) + buf.WriteString("\n") + buf.WriteString(fmt.Sprintf("% 16s | % 8s | % 16s | %s\n", "total", "count", "per", "type")) + buf.WriteString("-----------------+----------+------------------+----------------\n") + for _, se := range ss { + if se.entry.count == 0 { + // Since we store all types linearly, we are not + // guaranteed that any entry actually has time. + continue + } + count += se.entry.count + total += se.entry.total + per := se.entry.total / time.Duration(se.entry.count) + buf.WriteString(fmt.Sprintf("% 16s | %8d | % 16s | %s\n", + se.entry.total, se.entry.count, per, se.name)) + } + buf.WriteString("-----------------+----------+------------------+----------------\n") + buf.WriteString(fmt.Sprintf("% 16s | % 8d | % 16s | [all]", + total, count, total/time.Duration(count))) + return string(buf.Bytes()) +} diff --git a/pkg/state/tests/BUILD b/pkg/state/tests/BUILD new file mode 100644 index 000000000..9297cafbe --- /dev/null +++ b/pkg/state/tests/BUILD @@ -0,0 +1,43 @@ +load("//tools:defs.bzl", "go_library", "go_test") + +package(licenses = ["notice"]) + +go_library( + name = "tests", + srcs = [ + "array.go", + "bench.go", + "integer.go", + "load.go", + "map.go", + "register.go", + "struct.go", + "tests.go", + ], + deps = [ + "//pkg/state", + "//pkg/state/pretty", + ], +) + +go_test( + name = "tests_test", + size = "small", + srcs = [ + "array_test.go", + "bench_test.go", + "bool_test.go", + "float_test.go", + "integer_test.go", + "load_test.go", + "map_test.go", + "register_test.go", + "string_test.go", + "struct_test.go", + ], + library = ":tests", + deps = [ + "//pkg/state", + "//pkg/state/wire", + ], +) diff --git a/pkg/state/tests/array.go b/pkg/state/tests/array.go new file mode 100644 index 000000000..0972a80e7 --- /dev/null +++ b/pkg/state/tests/array.go @@ -0,0 +1,35 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +// +stateify savable +type arrayContainer struct { + v [1]interface{} +} + +// +stateify savable +type arrayPtrContainer struct { + v *[1]interface{} +} + +// +stateify savable +type sliceContainer struct { + v []interface{} +} + +// +stateify savable +type slicePtrContainer struct { + v *[]interface{} +} diff --git a/pkg/state/tests/array_test.go b/pkg/state/tests/array_test.go new file mode 100644 index 000000000..a347b2947 --- /dev/null +++ b/pkg/state/tests/array_test.go @@ -0,0 +1,134 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "reflect" + "testing" +) + +var allArrayPrimitives = []interface{}{ + [1]bool{}, + [1]bool{true}, + [2]bool{false, true}, + [1]int{}, + [1]int{1}, + [2]int{0, 1}, + [1]int8{}, + [1]int8{1}, + [2]int8{0, 1}, + [1]int16{}, + [1]int16{1}, + [2]int16{0, 1}, + [1]int32{}, + [1]int32{1}, + [2]int32{0, 1}, + [1]int64{}, + [1]int64{1}, + [2]int64{0, 1}, + [1]uint{}, + [1]uint{1}, + [2]uint{0, 1}, + [1]uintptr{}, + [1]uintptr{1}, + [2]uintptr{0, 1}, + [1]uint8{}, + [1]uint8{1}, + [2]uint8{0, 1}, + [1]uint16{}, + [1]uint16{1}, + [2]uint16{0, 1}, + [1]uint32{}, + [1]uint32{1}, + [2]uint32{0, 1}, + [1]uint64{}, + [1]uint64{1}, + [2]uint64{0, 1}, + [1]string{}, + [1]string{""}, + [1]string{nonEmptyString}, + [2]string{"", nonEmptyString}, +} + +func TestArrayPrimitives(t *testing.T) { + runTestCases(t, false, "plain", flatten(allArrayPrimitives)) + runTestCases(t, false, "pointers", pointersTo(flatten(allArrayPrimitives))) + runTestCases(t, false, "interfaces", interfacesTo(flatten(allArrayPrimitives))) + runTestCases(t, false, "interfacesToPointers", interfacesTo(pointersTo(flatten(allArrayPrimitives)))) +} + +func TestSlices(t *testing.T) { + var allSlices = flatten( + filter(allArrayPrimitives, func(o interface{}) (interface{}, bool) { + v := reflect.New(reflect.TypeOf(o)).Elem() + v.Set(reflect.ValueOf(o)) + return v.Slice(0, v.Len()).Interface(), true + }), + filter(allArrayPrimitives, func(o interface{}) (interface{}, bool) { + v := reflect.New(reflect.TypeOf(o)).Elem() + v.Set(reflect.ValueOf(o)) + if v.Len() == 0 { + // Return the pure "nil" value for the slice. + return reflect.New(v.Slice(0, 0).Type()).Elem().Interface(), true + } + return v.Slice(1, v.Len()).Interface(), true + }), + filter(allArrayPrimitives, func(o interface{}) (interface{}, bool) { + v := reflect.New(reflect.TypeOf(o)).Elem() + v.Set(reflect.ValueOf(o)) + if v.Len() == 0 { + // Return the zero-valued slice. + return reflect.MakeSlice(v.Slice(0, 0).Type(), 0, 0).Interface(), true + } + return v.Slice(0, v.Len()-1).Interface(), true + }), + ) + runTestCases(t, false, "plain", allSlices) + runTestCases(t, false, "pointers", pointersTo(allSlices)) + runTestCases(t, false, "interfaces", interfacesTo(allSlices)) + runTestCases(t, false, "interfacesToPointers", interfacesTo(pointersTo(allSlices))) +} + +func TestArrayContainers(t *testing.T) { + var ( + emptyArray [1]interface{} + fullArray [1]interface{} + ) + fullArray[0] = &emptyArray + runTestCases(t, false, "", []interface{}{ + arrayContainer{v: emptyArray}, + arrayContainer{v: fullArray}, + arrayPtrContainer{v: nil}, + arrayPtrContainer{v: &emptyArray}, + arrayPtrContainer{v: &fullArray}, + }) +} + +func TestSliceContainers(t *testing.T) { + var ( + nilSlice []interface{} + emptySlice = make([]interface{}, 0) + fullSlice = []interface{}{nil} + ) + runTestCases(t, false, "", []interface{}{ + sliceContainer{v: nilSlice}, + sliceContainer{v: emptySlice}, + sliceContainer{v: fullSlice}, + slicePtrContainer{v: nil}, + slicePtrContainer{v: &nilSlice}, + slicePtrContainer{v: &emptySlice}, + slicePtrContainer{v: &fullSlice}, + }) +} diff --git a/pkg/state/tests/bench.go b/pkg/state/tests/bench.go new file mode 100644 index 000000000..40869cdfb --- /dev/null +++ b/pkg/state/tests/bench.go @@ -0,0 +1,24 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +// +stateify savable +type benchStruct struct { + B *benchStruct // Must be exported for gob. +} + +func (b *benchStruct) afterLoad() { + // Do nothing, just force scheduling. +} diff --git a/pkg/state/tests/bench_test.go b/pkg/state/tests/bench_test.go new file mode 100644 index 000000000..7e102c907 --- /dev/null +++ b/pkg/state/tests/bench_test.go @@ -0,0 +1,153 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "bytes" + "context" + "encoding/gob" + "fmt" + "testing" + + "gvisor.dev/gvisor/pkg/state" + "gvisor.dev/gvisor/pkg/state/wire" +) + +// buildPtrObject builds a benchmark object. +func buildPtrObject(n int) interface{} { + b := new(benchStruct) + for i := 0; i < n; i++ { + b = &benchStruct{B: b} + } + return b +} + +// buildMapObject builds a benchmark object. +func buildMapObject(n int) interface{} { + b := new(benchStruct) + m := make(map[int]*benchStruct) + for i := 0; i < n; i++ { + m[i] = b + } + return &m +} + +// buildSliceObject builds a benchmark object. +func buildSliceObject(n int) interface{} { + b := new(benchStruct) + s := make([]*benchStruct, 0, n) + for i := 0; i < n; i++ { + s = append(s, b) + } + return &s +} + +var allObjects = map[string]struct { + New func(int) interface{} +}{ + "ptr": { + New: buildPtrObject, + }, + "map": { + New: buildMapObject, + }, + "slice": { + New: buildSliceObject, + }, +} + +func buildObjects(n int, fn func(int) interface{}) (iters int, v interface{}) { + // maxSize is the maximum size of an individual object below. For an N + // larger than this, we start to return multiple objects. + const maxSize = 1024 + if n <= maxSize { + return 1, fn(n) + } + iters = (n + maxSize - 1) / maxSize + return iters, fn(maxSize) +} + +// gobSave is a version of save using gob (no stats available). +func gobSave(_ context.Context, w wire.Writer, v interface{}) (_ state.Stats, err error) { + enc := gob.NewEncoder(w) + err = enc.Encode(v) + return +} + +// gobLoad is a version of load using gob (no stats available). +func gobLoad(_ context.Context, r wire.Reader, v interface{}) (_ state.Stats, err error) { + dec := gob.NewDecoder(r) + err = dec.Decode(v) + return +} + +var allAlgos = map[string]struct { + Save func(context.Context, wire.Writer, interface{}) (state.Stats, error) + Load func(context.Context, wire.Reader, interface{}) (state.Stats, error) + MaxPtr int +}{ + "state": { + Save: state.Save, + Load: state.Load, + }, + "gob": { + Save: gobSave, + Load: gobLoad, + }, +} + +func BenchmarkEncoding(b *testing.B) { + for objName, objInfo := range allObjects { + for algoName, algoInfo := range allAlgos { + b.Run(fmt.Sprintf("%s/%s", objName, algoName), func(b *testing.B) { + b.StopTimer() + n, v := buildObjects(b.N, objInfo.New) + b.ReportAllocs() + b.StartTimer() + for i := 0; i < n; i++ { + if _, err := algoInfo.Save(context.Background(), discard{}, v); err != nil { + b.Errorf("save failed: %v", err) + } + } + b.StopTimer() + }) + } + } +} + +func BenchmarkDecoding(b *testing.B) { + for objName, objInfo := range allObjects { + for algoName, algoInfo := range allAlgos { + b.Run(fmt.Sprintf("%s/%s", objName, algoName), func(b *testing.B) { + b.StopTimer() + n, v := buildObjects(b.N, objInfo.New) + buf := new(bytes.Buffer) + if _, err := algoInfo.Save(context.Background(), buf, v); err != nil { + b.Errorf("save failed: %v", err) + } + b.ReportAllocs() + b.StartTimer() + var r bytes.Reader + for i := 0; i < n; i++ { + r.Reset(buf.Bytes()) + if _, err := algoInfo.Load(context.Background(), &r, v); err != nil { + b.Errorf("load failed: %v", err) + } + } + b.StopTimer() + }) + } + } +} diff --git a/pkg/state/tests/bool_test.go b/pkg/state/tests/bool_test.go new file mode 100644 index 000000000..e17cfacf9 --- /dev/null +++ b/pkg/state/tests/bool_test.go @@ -0,0 +1,31 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "testing" +) + +var allBools = []bool{ + true, + false, +} + +func TestBool(t *testing.T) { + runTestCases(t, false, "plain", flatten(allBools)) + runTestCases(t, false, "pointers", pointersTo(flatten(allBools))) + runTestCases(t, false, "interfaces", interfacesTo(flatten(allBools))) + runTestCases(t, false, "interfacesToPointers", interfacesTo(pointersTo(flatten(allBools)))) +} diff --git a/pkg/state/tests/float_test.go b/pkg/state/tests/float_test.go new file mode 100644 index 000000000..3e89edd9c --- /dev/null +++ b/pkg/state/tests/float_test.go @@ -0,0 +1,118 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "math" + "testing" +) + +var safeFloat32s = []float32{ + float32(0.0), + float32(1.0), + float32(-1.0), + float32(math.Inf(1)), + float32(math.Inf(-1)), +} + +var allFloat32s = append(safeFloat32s, float32(math.NaN())) + +var safeFloat64s = []float64{ + float64(0.0), + float64(1.0), + float64(-1.0), + math.Inf(1), + math.Inf(-1), +} + +var allFloat64s = append(safeFloat64s, math.NaN()) + +func TestFloat(t *testing.T) { + runTestCases(t, false, "plain", flatten( + allFloat32s, + allFloat64s, + )) + // See checkEqual for why NaNs are missing. + runTestCases(t, false, "pointers", pointersTo(flatten( + safeFloat32s, + safeFloat64s, + ))) + runTestCases(t, false, "interfaces", interfacesTo(flatten( + safeFloat32s, + safeFloat64s, + ))) + runTestCases(t, false, "interfacesToPointers", interfacesTo(pointersTo(flatten( + safeFloat32s, + safeFloat64s, + )))) +} + +const onlyDouble float64 = 1.0000000000000002 + +func TestFloatTruncation(t *testing.T) { + runTestCases(t, true, "pass", []interface{}{ + truncatingFloat32{save: onlyDouble}, + }) + runTestCases(t, false, "fail", []interface{}{ + truncatingFloat32{save: 1.0}, + }) +} + +var safeComplex64s = combine(safeFloat32s, safeFloat32s, func(i, j interface{}) interface{} { + return complex(i.(float32), j.(float32)) +}) + +var allComplex64s = combine(allFloat32s, allFloat32s, func(i, j interface{}) interface{} { + return complex(i.(float32), j.(float32)) +}) + +var safeComplex128s = combine(safeFloat64s, safeFloat64s, func(i, j interface{}) interface{} { + return complex(i.(float64), j.(float64)) +}) + +var allComplex128s = combine(allFloat64s, allFloat64s, func(i, j interface{}) interface{} { + return complex(i.(float64), j.(float64)) +}) + +func TestComplex(t *testing.T) { + runTestCases(t, false, "plain", flatten( + allComplex64s, + allComplex128s, + )) + // See TestFloat; same issue. + runTestCases(t, false, "pointers", pointersTo(flatten( + safeComplex64s, + safeComplex128s, + ))) + runTestCases(t, false, "interfacse", interfacesTo(flatten( + safeComplex64s, + safeComplex128s, + ))) + runTestCases(t, false, "interfacesTo", interfacesTo(pointersTo(flatten( + safeComplex64s, + safeComplex128s, + )))) +} + +func TestComplexTruncation(t *testing.T) { + runTestCases(t, true, "pass", []interface{}{ + truncatingComplex64{save: complex(onlyDouble, onlyDouble)}, + truncatingComplex64{save: complex(1.0, onlyDouble)}, + truncatingComplex64{save: complex(onlyDouble, 1.0)}, + }) + runTestCases(t, false, "fail", []interface{}{ + truncatingComplex64{save: complex(1.0, 1.0)}, + }) +} diff --git a/pkg/state/tests/integer.go b/pkg/state/tests/integer.go new file mode 100644 index 000000000..ca403eed1 --- /dev/null +++ b/pkg/state/tests/integer.go @@ -0,0 +1,163 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "gvisor.dev/gvisor/pkg/state" +) + +// +stateify type +type truncatingUint8 struct { + save uint64 + load uint8 `state:"nosave"` +} + +func (t *truncatingUint8) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingUint8) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = uint64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingUint8)(nil) + +// +stateify type +type truncatingUint16 struct { + save uint64 + load uint16 `state:"nosave"` +} + +func (t *truncatingUint16) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingUint16) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = uint64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingUint16)(nil) + +// +stateify type +type truncatingUint32 struct { + save uint64 + load uint32 `state:"nosave"` +} + +func (t *truncatingUint32) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingUint32) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = uint64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingUint32)(nil) + +// +stateify type +type truncatingInt8 struct { + save int64 + load int8 `state:"nosave"` +} + +func (t *truncatingInt8) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingInt8) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = int64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingInt8)(nil) + +// +stateify type +type truncatingInt16 struct { + save int64 + load int16 `state:"nosave"` +} + +func (t *truncatingInt16) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingInt16) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = int64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingInt16)(nil) + +// +stateify type +type truncatingInt32 struct { + save int64 + load int32 `state:"nosave"` +} + +func (t *truncatingInt32) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingInt32) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = int64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingInt32)(nil) + +// +stateify type +type truncatingFloat32 struct { + save float64 + load float32 `state:"nosave"` +} + +func (t *truncatingFloat32) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingFloat32) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = float64(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingFloat32)(nil) + +// +stateify type +type truncatingComplex64 struct { + save complex128 + load complex64 `state:"nosave"` +} + +func (t *truncatingComplex64) StateSave(m state.Sink) { + m.Save(0, &t.save) +} + +func (t *truncatingComplex64) StateLoad(m state.Source) { + m.Load(0, &t.load) + t.save = complex128(t.load) + t.load = 0 +} + +var _ state.SaverLoader = (*truncatingComplex64)(nil) diff --git a/pkg/state/tests/integer_test.go b/pkg/state/tests/integer_test.go new file mode 100644 index 000000000..d3931c952 --- /dev/null +++ b/pkg/state/tests/integer_test.go @@ -0,0 +1,94 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "math" + "testing" +) + +var ( + allIntTs = []int{-1, 0, 1} + allInt8s = []int8{math.MinInt8, -1, 0, 1, math.MaxInt8} + allInt16s = []int16{math.MinInt16, -1, 0, 1, math.MaxInt16} + allInt32s = []int32{math.MinInt32, -1, 0, 1, math.MaxInt32} + allInt64s = []int64{math.MinInt64, -1, 0, 1, math.MaxInt64} + allUintTs = []uint{0, 1} + allUintptrs = []uintptr{0, 1, ^uintptr(0)} + allUint8s = []uint8{0, 1, math.MaxUint8} + allUint16s = []uint16{0, 1, math.MaxUint16} + allUint32s = []uint32{0, 1, math.MaxUint32} + allUint64s = []uint64{0, 1, math.MaxUint64} +) + +var allInts = flatten( + allIntTs, + allInt8s, + allInt16s, + allInt32s, + allInt64s, +) + +var allUints = flatten( + allUintTs, + allUintptrs, + allUint8s, + allUint16s, + allUint32s, + allUint64s, +) + +func TestInt(t *testing.T) { + runTestCases(t, false, "plain", allInts) + runTestCases(t, false, "pointers", pointersTo(allInts)) + runTestCases(t, false, "interfaces", interfacesTo(allInts)) + runTestCases(t, false, "interfacesTo", interfacesTo(pointersTo(allInts))) +} + +func TestIntTruncation(t *testing.T) { + runTestCases(t, true, "pass", []interface{}{ + truncatingInt8{save: math.MinInt8 - 1}, + truncatingInt16{save: math.MinInt16 - 1}, + truncatingInt32{save: math.MinInt32 - 1}, + truncatingInt8{save: math.MaxInt8 + 1}, + truncatingInt16{save: math.MaxInt16 + 1}, + truncatingInt32{save: math.MaxInt32 + 1}, + }) + runTestCases(t, false, "fail", []interface{}{ + truncatingInt8{save: 1}, + truncatingInt16{save: 1}, + truncatingInt32{save: 1}, + }) +} + +func TestUint(t *testing.T) { + runTestCases(t, false, "plain", allUints) + runTestCases(t, false, "pointers", pointersTo(allUints)) + runTestCases(t, false, "interfaces", interfacesTo(allUints)) + runTestCases(t, false, "interfacesTo", interfacesTo(pointersTo(allUints))) +} + +func TestUintTruncation(t *testing.T) { + runTestCases(t, true, "pass", []interface{}{ + truncatingUint8{save: math.MaxUint8 + 1}, + truncatingUint16{save: math.MaxUint16 + 1}, + truncatingUint32{save: math.MaxUint32 + 1}, + }) + runTestCases(t, false, "fail", []interface{}{ + truncatingUint8{save: 1}, + truncatingUint16{save: 1}, + truncatingUint32{save: 1}, + }) +} diff --git a/pkg/state/tests/load.go b/pkg/state/tests/load.go new file mode 100644 index 000000000..a8350c0f3 --- /dev/null +++ b/pkg/state/tests/load.go @@ -0,0 +1,61 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +// +stateify savable +type genericContainer struct { + v interface{} +} + +// +stateify savable +type afterLoadStruct struct { + v int `state:"nosave"` +} + +func (a *afterLoadStruct) afterLoad() { + a.v++ +} + +// +stateify savable +type valueLoadStruct struct { + v int `state:".(int64)"` +} + +func (v *valueLoadStruct) saveV() int64 { + return int64(v.v) // Save as int64. +} + +func (v *valueLoadStruct) loadV(value int64) { + v.v = int(value) // Load as int. +} + +// +stateify savable +type cycleStruct struct { + c *cycleStruct +} + +// +stateify savable +type badCycleStruct struct { + b *badCycleStruct `state:"wait"` +} + +func (b *badCycleStruct) afterLoad() { + if b.b != b { + // This is not executable, since AfterLoad requires that the + // object and all dependencies are complete. This should cause + // a deadlock error during load. + panic("badCycleStruct.afterLoad called") + } +} diff --git a/pkg/state/tests/load_test.go b/pkg/state/tests/load_test.go new file mode 100644 index 000000000..1e9794296 --- /dev/null +++ b/pkg/state/tests/load_test.go @@ -0,0 +1,70 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "testing" +) + +func TestLoadHooks(t *testing.T) { + runTestCases(t, false, "load-hooks", []interface{}{ + &afterLoadStruct{v: 1}, + &valueLoadStruct{v: 1}, + &genericContainer{v: &afterLoadStruct{v: 1}}, + &genericContainer{v: &valueLoadStruct{v: 1}}, + &sliceContainer{v: []interface{}{&afterLoadStruct{v: 1}}}, + &sliceContainer{v: []interface{}{&valueLoadStruct{v: 1}}}, + &mapContainer{v: map[int]interface{}{0: &afterLoadStruct{v: 1}}}, + &mapContainer{v: map[int]interface{}{0: &valueLoadStruct{v: 1}}}, + }) +} + +func TestCycles(t *testing.T) { + // cs is a single object cycle. + cs := cycleStruct{nil} + cs.c = &cs + + // cs1 and cs2 are in a two object cycle. + cs1 := cycleStruct{nil} + cs2 := cycleStruct{nil} + cs1.c = &cs2 + cs2.c = &cs1 + + runTestCases(t, false, "cycles", []interface{}{ + cs, + cs1, + }) +} + +func TestDeadlock(t *testing.T) { + // bs is a single object cycle. This does not cause deadlock because an + // object cannot wait for itself. + bs := badCycleStruct{nil} + bs.b = &bs + + runTestCases(t, false, "self", []interface{}{ + &bs, + }) + + // bs2 and bs2 are in a deadlocking cycle. + bs1 := badCycleStruct{nil} + bs2 := badCycleStruct{nil} + bs1.b = &bs2 + bs2.b = &bs1 + + runTestCases(t, true, "deadlock", []interface{}{ + &bs1, + }) +} diff --git a/pkg/state/tests/map.go b/pkg/state/tests/map.go new file mode 100644 index 000000000..db4e548f1 --- /dev/null +++ b/pkg/state/tests/map.go @@ -0,0 +1,28 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +// +stateify savable +type mapContainer struct { + v map[int]interface{} +} + +// +stateify savable +type mapPtrContainer struct { + v *map[int]interface{} +} + +// +stateify savable +type registeredMapStruct struct{} diff --git a/pkg/state/tests/map_test.go b/pkg/state/tests/map_test.go new file mode 100644 index 000000000..92bf0fc01 --- /dev/null +++ b/pkg/state/tests/map_test.go @@ -0,0 +1,90 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "reflect" + "testing" +) + +var allMapPrimitives = []interface{}{ + bool(true), + int(1), + int8(1), + int16(1), + int32(1), + int64(1), + uint(1), + uintptr(1), + uint8(1), + uint16(1), + uint32(1), + uint64(1), + string(""), + registeredMapStruct{}, +} + +var allMapKeys = flatten(allMapPrimitives, pointersTo(allMapPrimitives)) + +var allMapValues = flatten(allMapPrimitives, pointersTo(allMapPrimitives), interfacesTo(allMapPrimitives)) + +var emptyMaps = combine(allMapKeys, allMapValues, func(v1, v2 interface{}) interface{} { + m := reflect.MakeMap(reflect.MapOf(reflect.TypeOf(v1), reflect.TypeOf(v2))) + return m.Interface() +}) + +var fullMaps = combine(allMapKeys, allMapValues, func(v1, v2 interface{}) interface{} { + m := reflect.MakeMap(reflect.MapOf(reflect.TypeOf(v1), reflect.TypeOf(v2))) + m.SetMapIndex(reflect.Zero(reflect.TypeOf(v1)), reflect.Zero(reflect.TypeOf(v2))) + return m.Interface() +}) + +func TestMapAliasing(t *testing.T) { + v := make(map[int]int) + ptrToV := &v + aliases := []map[int]int{v, v} + runTestCases(t, false, "", []interface{}{ptrToV, aliases}) +} + +func TestMapsEmpty(t *testing.T) { + runTestCases(t, false, "plain", emptyMaps) + runTestCases(t, false, "pointers", pointersTo(emptyMaps)) + runTestCases(t, false, "interfaces", interfacesTo(emptyMaps)) + runTestCases(t, false, "interfacesToPointers", interfacesTo(pointersTo(emptyMaps))) +} + +func TestMapsFull(t *testing.T) { + runTestCases(t, false, "plain", fullMaps) + runTestCases(t, false, "pointers", pointersTo(fullMaps)) + runTestCases(t, false, "interfaces", interfacesTo(fullMaps)) + runTestCases(t, false, "interfacesToPointer", interfacesTo(pointersTo(fullMaps))) +} + +func TestMapContainers(t *testing.T) { + var ( + nilMap map[int]interface{} + emptyMap = make(map[int]interface{}) + fullMap = map[int]interface{}{0: nil} + ) + runTestCases(t, false, "", []interface{}{ + mapContainer{v: nilMap}, + mapContainer{v: emptyMap}, + mapContainer{v: fullMap}, + mapPtrContainer{v: nil}, + mapPtrContainer{v: &nilMap}, + mapPtrContainer{v: &emptyMap}, + mapPtrContainer{v: &fullMap}, + }) +} diff --git a/pkg/state/tests/register.go b/pkg/state/tests/register.go new file mode 100644 index 000000000..074d86315 --- /dev/null +++ b/pkg/state/tests/register.go @@ -0,0 +1,21 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +// +stateify savable +type alreadyRegisteredStruct struct{} + +// +stateify savable +type alreadyRegisteredOther int diff --git a/pkg/state/tests/register_test.go b/pkg/state/tests/register_test.go new file mode 100644 index 000000000..c829753cc --- /dev/null +++ b/pkg/state/tests/register_test.go @@ -0,0 +1,167 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "testing" + + "gvisor.dev/gvisor/pkg/state" +) + +// faker calls itself whatever is in the name field. +type faker struct { + Name string + Fields []string +} + +func (f *faker) StateTypeName() string { + return f.Name +} + +func (f *faker) StateFields() []string { + return f.Fields +} + +// fakerWithSaverLoader has all it needs. +type fakerWithSaverLoader struct { + faker +} + +func (f *fakerWithSaverLoader) StateSave(m state.Sink) {} + +func (f *fakerWithSaverLoader) StateLoad(m state.Source) {} + +// fakerOther calls itself .. uh, itself? +type fakerOther string + +func (f *fakerOther) StateTypeName() string { + return string(*f) +} + +func (f *fakerOther) StateFields() []string { + return nil +} + +func newFakerOther(name string) *fakerOther { + f := fakerOther(name) + return &f +} + +// fakerOtherBadFields returns non-nil fields. +type fakerOtherBadFields string + +func (f *fakerOtherBadFields) StateTypeName() string { + return string(*f) +} + +func (f *fakerOtherBadFields) StateFields() []string { + return []string{string(*f)} +} + +func newFakerOtherBadFields(name string) *fakerOtherBadFields { + f := fakerOtherBadFields(name) + return &f +} + +// fakerOtherSaverLoader implements SaverLoader methods. +type fakerOtherSaverLoader string + +func (f *fakerOtherSaverLoader) StateTypeName() string { + return string(*f) +} + +func (f *fakerOtherSaverLoader) StateFields() []string { + return nil +} + +func (f *fakerOtherSaverLoader) StateSave(m state.Sink) {} + +func (f *fakerOtherSaverLoader) StateLoad(m state.Source) {} + +func newFakerOtherSaverLoader(name string) *fakerOtherSaverLoader { + f := fakerOtherSaverLoader(name) + return &f +} + +func TestRegisterPrimitives(t *testing.T) { + for _, typeName := range []string{ + "int", + "int8", + "int16", + "int32", + "int64", + "uint", + "uintptr", + "uint8", + "uint16", + "uint32", + "uint64", + "float32", + "float64", + "complex64", + "complex128", + "string", + } { + t.Run("struct/"+typeName, func(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("Registering type %q did not panic", typeName) + } + }() + state.Register(&faker{ + Name: typeName, + }) + }) + t.Run("other/"+typeName, func(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("Registering type %q did not panic", typeName) + } + }() + state.Register(newFakerOther(typeName)) + }) + } +} + +func TestRegisterBad(t *testing.T) { + const ( + goodName = "foo" + firstField = "a" + secondField = "b" + ) + for name, object := range map[string]state.Type{ + "non-struct-with-fields": newFakerOtherBadFields(goodName), + "non-struct-with-saverloader": newFakerOtherSaverLoader(goodName), + "struct-without-saverloader": &faker{Name: goodName}, + "non-struct-duplicate-with-struct": newFakerOther((new(alreadyRegisteredStruct)).StateTypeName()), + "non-struct-duplicate-with-non-struct": newFakerOther((new(alreadyRegisteredOther)).StateTypeName()), + "struct-duplicate-with-struct": &fakerWithSaverLoader{faker{Name: (new(alreadyRegisteredStruct)).StateTypeName()}}, + "struct-duplicate-with-non-struct": &fakerWithSaverLoader{faker{Name: (new(alreadyRegisteredOther)).StateTypeName()}}, + "struct-with-empty-field": &fakerWithSaverLoader{faker{Name: goodName, Fields: []string{""}}}, + "struct-with-empty-field-and-non-empty": &fakerWithSaverLoader{faker{Name: goodName, Fields: []string{firstField, ""}}}, + "struct-with-duplicate-field": &fakerWithSaverLoader{faker{Name: goodName, Fields: []string{firstField, firstField}}}, + "struct-with-duplicate-field-and-non-dup": &fakerWithSaverLoader{faker{Name: goodName, Fields: []string{firstField, secondField, firstField}}}, + } { + t.Run(name, func(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("Registering object %#v did not panic", object) + } + }() + state.Register(object) + }) + + } +} diff --git a/pkg/state/tests/string_test.go b/pkg/state/tests/string_test.go new file mode 100644 index 000000000..44f5a562c --- /dev/null +++ b/pkg/state/tests/string_test.go @@ -0,0 +1,34 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "testing" +) + +const nonEmptyString = "hello world" + +var allStrings = []string{ + "", + nonEmptyString, + "\\0", +} + +func TestString(t *testing.T) { + runTestCases(t, false, "plain", flatten(allStrings)) + runTestCases(t, false, "pointers", pointersTo(flatten(allStrings))) + runTestCases(t, false, "interfaces", interfacesTo(flatten(allStrings))) + runTestCases(t, false, "interfacesToPointers", interfacesTo(pointersTo(flatten(allStrings)))) +} diff --git a/pkg/state/tests/struct.go b/pkg/state/tests/struct.go new file mode 100644 index 000000000..bd2c2b399 --- /dev/null +++ b/pkg/state/tests/struct.go @@ -0,0 +1,65 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +type unregisteredEmptyStruct struct{} + +// typeOnlyEmptyStruct just implements the state.Type interface. +type typeOnlyEmptyStruct struct{} + +func (*typeOnlyEmptyStruct) StateTypeName() string { return "registeredEmptyStruct" } + +func (*typeOnlyEmptyStruct) StateFields() []string { return nil } + +// +stateify savable +type savableEmptyStruct struct{} + +// +stateify savable +type emptyStructPointer struct { + nothing *struct{} +} + +// +stateify savable +type outerSame struct { + inner inner +} + +// +stateify savable +type outerFieldFirst struct { + inner inner + v int64 +} + +// +stateify savable +type outerFieldSecond struct { + v int64 + inner inner +} + +// +stateify savable +type outerArray struct { + inner [2]inner +} + +// +stateify savable +type inner struct { + v int64 +} + +// +stateify savable +type system struct { + v1 interface{} + v2 interface{} +} diff --git a/pkg/state/tests/struct_test.go b/pkg/state/tests/struct_test.go new file mode 100644 index 000000000..de9d17aa7 --- /dev/null +++ b/pkg/state/tests/struct_test.go @@ -0,0 +1,89 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tests + +import ( + "testing" + + "gvisor.dev/gvisor/pkg/state" +) + +func TestEmptyStruct(t *testing.T) { + runTestCases(t, false, "plain", []interface{}{ + unregisteredEmptyStruct{}, + typeOnlyEmptyStruct{}, + savableEmptyStruct{}, + }) + runTestCases(t, false, "pointers", pointersTo([]interface{}{ + unregisteredEmptyStruct{}, + typeOnlyEmptyStruct{}, + savableEmptyStruct{}, + })) + runTestCases(t, false, "interfaces-pass", interfacesTo([]interface{}{ + // Only registered types can be dispatched via interfaces. All + // other types should fail, even if it is the empty struct. + savableEmptyStruct{}, + })) + runTestCases(t, true, "interfaces-fail", interfacesTo([]interface{}{ + unregisteredEmptyStruct{}, + typeOnlyEmptyStruct{}, + })) + runTestCases(t, false, "interfacesToPointers-pass", interfacesTo(pointersTo([]interface{}{ + savableEmptyStruct{}, + }))) + runTestCases(t, true, "interfacesToPointers-fail", interfacesTo(pointersTo([]interface{}{ + unregisteredEmptyStruct{}, + typeOnlyEmptyStruct{}, + }))) + + // Ensuring empty struct aliasing works. + es := emptyStructPointer{new(struct{})} + runTestCases(t, false, "empty-struct-pointers", []interface{}{ + emptyStructPointer{}, + es, + []emptyStructPointer{es, es}, // Same pointer. + }) +} + +func TestRegisterTypeOnlyStruct(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("Register did not panic") + } + }() + state.Register((*typeOnlyEmptyStruct)(nil)) +} + +func TestEmbeddedPointers(t *testing.T) { + var ( + ofs outerSame + of1 outerFieldFirst + of2 outerFieldSecond + oa outerArray + ) + + runTestCases(t, false, "embedded-pointers", []interface{}{ + system{&ofs, &ofs.inner}, + system{&ofs.inner, &ofs}, + system{&of1, &of1.inner}, + system{&of1.inner, &of1}, + system{&of2, &of2.inner}, + system{&of2.inner, &of2}, + system{&oa, &oa.inner[0]}, + system{&oa, &oa.inner[1]}, + system{&oa.inner[0], &oa}, + system{&oa.inner[1], &oa}, + }) +} diff --git a/pkg/state/tests/tests.go b/pkg/state/tests/tests.go new file mode 100644 index 000000000..435a0e9db --- /dev/null +++ b/pkg/state/tests/tests.go @@ -0,0 +1,215 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package tests tests the state packages. +package tests + +import ( + "bytes" + "context" + "fmt" + "math" + "reflect" + "testing" + + "gvisor.dev/gvisor/pkg/state" + "gvisor.dev/gvisor/pkg/state/pretty" +) + +// discard is an implementation of wire.Writer. +type discard struct{} + +// Write implements wire.Writer.Write. +func (discard) Write(p []byte) (int, error) { return len(p), nil } + +// WriteByte implements wire.Writer.WriteByte. +func (discard) WriteByte(byte) error { return nil } + +// checkEqual checks if two objects are equal. +// +// N.B. This only handles one level of dereferences for NaN. Otherwise we +// would need to fork the entire implementation of reflect.DeepEqual. +func checkEqual(root, loadedValue interface{}) bool { + if reflect.DeepEqual(root, loadedValue) { + return true + } + + // NaN is not equal to itself. We handle the case of raw floating point + // primitives here, but don't handle this case nested. + rf32, ok1 := root.(float32) + lf32, ok2 := loadedValue.(float32) + if ok1 && ok2 && math.IsNaN(float64(rf32)) && math.IsNaN(float64(lf32)) { + return true + } + rf64, ok1 := root.(float64) + lf64, ok2 := loadedValue.(float64) + if ok1 && ok2 && math.IsNaN(rf64) && math.IsNaN(lf64) { + return true + } + + // Same real for complex numbers. + rc64, ok1 := root.(complex64) + lc64, ok2 := root.(complex64) + if ok1 && ok2 { + return checkEqual(real(rc64), real(lc64)) && checkEqual(imag(rc64), imag(lc64)) + } + rc128, ok1 := root.(complex128) + lc128, ok2 := root.(complex128) + if ok1 && ok2 { + return checkEqual(real(rc128), real(lc128)) && checkEqual(imag(rc128), imag(lc128)) + } + + return false +} + +// runTestCases runs a test for each object in objects. +func runTestCases(t *testing.T, shouldFail bool, prefix string, objects []interface{}) { + t.Helper() + for i, root := range objects { + t.Run(fmt.Sprintf("%s%d", prefix, i), func(t *testing.T) { + t.Logf("Original object:\n%#v", root) + + // Save the passed object. + saveBuffer := &bytes.Buffer{} + saveObjectPtr := reflect.New(reflect.TypeOf(root)) + saveObjectPtr.Elem().Set(reflect.ValueOf(root)) + saveStats, err := state.Save(context.Background(), saveBuffer, saveObjectPtr.Interface()) + if err != nil { + if shouldFail { + return + } + t.Fatalf("Save failed unexpectedly: %v", err) + } + + // Dump the serialized proto to aid with debugging. + var ppBuf bytes.Buffer + t.Logf("Raw state:\n%v", saveBuffer.Bytes()) + if err := pretty.PrintText(&ppBuf, bytes.NewReader(saveBuffer.Bytes())); err != nil { + // We don't count this as a test failure if we + // have shouldFail set, but we will count as a + // failure if we were not expecting to fail. + if !shouldFail { + t.Errorf("PrettyPrint(html=false) failed unexpected: %v", err) + } + } + if err := pretty.PrintHTML(discard{}, bytes.NewReader(saveBuffer.Bytes())); err != nil { + // See above. + if !shouldFail { + t.Errorf("PrettyPrint(html=true) failed unexpected: %v", err) + } + } + t.Logf("Encoded state:\n%s", ppBuf.String()) + t.Logf("Save stats:\n%s", saveStats.String()) + + // Load a new copy of the object. + loadObjectPtr := reflect.New(reflect.TypeOf(root)) + loadStats, err := state.Load(context.Background(), bytes.NewReader(saveBuffer.Bytes()), loadObjectPtr.Interface()) + if err != nil { + if shouldFail { + return + } + t.Fatalf("Load failed unexpectedly: %v", err) + } + + // Compare the values. + loadedValue := loadObjectPtr.Elem().Interface() + if !checkEqual(root, loadedValue) { + if shouldFail { + return + } + t.Fatalf("Objects differ:\n\toriginal: %#v\n\tloaded: %#v\n", root, loadedValue) + } + + // Everything went okay. Is that good? + if shouldFail { + t.Fatalf("This test was expected to fail, but didn't.") + } + t.Logf("Load stats:\n%s", loadStats.String()) + + // Truncate half the bytes in the byte stream, + // and ensure that we can't restore. Then + // truncate only the final byte and ensure that + // we can't restore. + l := saveBuffer.Len() + halfReader := bytes.NewReader(saveBuffer.Bytes()[:l/2]) + if _, err := state.Load(context.Background(), halfReader, loadObjectPtr.Interface()); err == nil { + t.Errorf("Load with half bytes succeeded unexpectedly.") + } + missingByteReader := bytes.NewReader(saveBuffer.Bytes()[:l-1]) + if _, err := state.Load(context.Background(), missingByteReader, loadObjectPtr.Interface()); err == nil { + t.Errorf("Load with missing byte succeeded unexpectedly.") + } + }) + } +} + +// convert converts the slice to an []interface{}. +func convert(v interface{}) (r []interface{}) { + s := reflect.ValueOf(v) // Must be slice. + for i := 0; i < s.Len(); i++ { + r = append(r, s.Index(i).Interface()) + } + return r +} + +// flatten flattens multiple slices. +func flatten(vs ...interface{}) (r []interface{}) { + for _, v := range vs { + r = append(r, convert(v)...) + } + return r +} + +// filter maps from one slice to another. +func filter(vs interface{}, fn func(interface{}) (interface{}, bool)) (r []interface{}) { + s := reflect.ValueOf(vs) + for i := 0; i < s.Len(); i++ { + v, ok := fn(s.Index(i).Interface()) + if ok { + r = append(r, v) + } + } + return r +} + +// combine combines objects in two slices as specified. +func combine(v1, v2 interface{}, fn func(_, _ interface{}) interface{}) (r []interface{}) { + s1 := reflect.ValueOf(v1) + s2 := reflect.ValueOf(v2) + for i := 0; i < s1.Len(); i++ { + for j := 0; j < s2.Len(); j++ { + // Combine using the given function. + r = append(r, fn(s1.Index(i).Interface(), s2.Index(j).Interface())) + } + } + return r +} + +// pointersTo is a filter function that returns pointers. +func pointersTo(vs interface{}) []interface{} { + return filter(vs, func(o interface{}) (interface{}, bool) { + v := reflect.New(reflect.TypeOf(o)) + v.Elem().Set(reflect.ValueOf(o)) + return v.Interface(), true + }) +} + +// interfacesTo is a filter function that returns interface objects. +func interfacesTo(vs interface{}) []interface{} { + return filter(vs, func(o interface{}) (interface{}, bool) { + var v [1]interface{} + v[0] = o + return v, true + }) +} diff --git a/pkg/state/types.go b/pkg/state/types.go new file mode 100644 index 000000000..215ef80f8 --- /dev/null +++ b/pkg/state/types.go @@ -0,0 +1,361 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package state + +import ( + "reflect" + "sort" + + "gvisor.dev/gvisor/pkg/state/wire" +) + +// assertValidType asserts that the type is valid. +func assertValidType(name string, fields []string) { + if name == "" { + Failf("type has empty name") + } + fieldsCopy := make([]string, len(fields)) + for i := 0; i < len(fields); i++ { + if fields[i] == "" { + Failf("field has empty name for type %q", name) + } + fieldsCopy[i] = fields[i] + } + sort.Slice(fieldsCopy, func(i, j int) bool { + return fieldsCopy[i] < fieldsCopy[j] + }) + for i := range fieldsCopy { + if i > 0 && fieldsCopy[i-1] == fieldsCopy[i] { + Failf("duplicate field %q for type %s", fieldsCopy[i], name) + } + } +} + +// typeEntry is an entry in the typeDatabase. +type typeEntry struct { + ID typeID + wire.Type +} + +// reconciledTypeEntry is a reconciled entry in the typeDatabase. +type reconciledTypeEntry struct { + wire.Type + LocalType reflect.Type + FieldOrder []int +} + +// typeEncodeDatabase is an internal TypeInfo database for encoding. +type typeEncodeDatabase struct { + // byType maps by type to the typeEntry. + byType map[reflect.Type]*typeEntry + + // lastID is the last used ID. + lastID typeID +} + +// makeTypeEncodeDatabase makes a typeDatabase. +func makeTypeEncodeDatabase() typeEncodeDatabase { + return typeEncodeDatabase{ + byType: make(map[reflect.Type]*typeEntry), + } +} + +// typeDecodeDatabase is an internal TypeInfo database for decoding. +type typeDecodeDatabase struct { + // byID maps by ID to type. + byID []*reconciledTypeEntry + + // pending are entries that are pending validation by Lookup. These + // will be reconciled with actual objects. Note that these will also be + // used to lookup types by name, since they may not be reconciled and + // there's little value to deleting from this map. + pending []*wire.Type +} + +// makeTypeDecodeDatabase makes a typeDatabase. +func makeTypeDecodeDatabase() typeDecodeDatabase { + return typeDecodeDatabase{} +} + +// lookupNameFields extracts the name and fields from an object. +func lookupNameFields(typ reflect.Type) (string, []string, bool) { + v := reflect.Zero(reflect.PtrTo(typ)).Interface() + t, ok := v.(Type) + if !ok { + // Is this a primitive? + if typ.Kind() == reflect.Interface { + return interfaceType, nil, true + } + name := typ.Name() + if _, ok := primitiveTypeDatabase[name]; !ok { + // This is not a known type, and not a primitive. The + // encoder may proceed for anonymous empty structs, or + // it may deference the type pointer and try again. + return "", nil, false + } + return name, nil, true + } + // Extract the name from the object. + name := t.StateTypeName() + fields := t.StateFields() + assertValidType(name, fields) + return name, fields, true +} + +// Lookup looks up or registers the given object. +// +// The bool indicates whether this is an existing entry: false means the entry +// did not exist, and true means the entry did exist. If this bool is false and +// the returned typeEntry are nil, then the obj did not implement the Type +// interface. +func (tdb *typeEncodeDatabase) Lookup(typ reflect.Type) (*typeEntry, bool) { + te, ok := tdb.byType[typ] + if !ok { + // Lookup the type information. + name, fields, ok := lookupNameFields(typ) + if !ok { + // Empty structs may still be encoded, so let the + // caller decide what to do from here. + return nil, false + } + + // Register the new type. + tdb.lastID++ + te = &typeEntry{ + ID: tdb.lastID, + Type: wire.Type{ + Name: name, + Fields: fields, + }, + } + + // All done. + tdb.byType[typ] = te + return te, false + } + return te, true +} + +// Register adds a typeID entry. +func (tbd *typeDecodeDatabase) Register(typ *wire.Type) { + assertValidType(typ.Name, typ.Fields) + tbd.pending = append(tbd.pending, typ) +} + +// LookupName looks up the type name by ID. +func (tbd *typeDecodeDatabase) LookupName(id typeID) string { + if len(tbd.pending) < int(id) { + // This is likely an encoder error? + Failf("type ID %d not available", id) + } + return tbd.pending[id-1].Name +} + +// LookupType looks up the type by ID. +func (tbd *typeDecodeDatabase) LookupType(id typeID) reflect.Type { + name := tbd.LookupName(id) + typ, ok := globalTypeDatabase[name] + if !ok { + // If not available, see if it's primitive. + typ, ok = primitiveTypeDatabase[name] + if !ok && name == interfaceType { + // Matches the built-in interface type. + var i interface{} + return reflect.TypeOf(&i).Elem() + } + if !ok { + // The type is perhaps not registered? + Failf("type name %q is not available", name) + } + return typ // Primitive type. + } + return typ // Registered type. +} + +// singleFieldOrder defines the field order for a single field. +var singleFieldOrder = []int{0} + +// Lookup looks up or registers the given object. +// +// First, the typeID is searched to see if this has already been appropriately +// reconciled. If no, then a reconcilation will take place that may result in a +// field ordering. If a nil reconciledTypeEntry is returned from this method, +// then the object does not support the Type interface. +// +// This method never returns nil. +func (tbd *typeDecodeDatabase) Lookup(id typeID, typ reflect.Type) *reconciledTypeEntry { + if len(tbd.byID) > int(id) && tbd.byID[id-1] != nil { + // Already reconciled. + return tbd.byID[id-1] + } + // The ID has not been reconciled yet. That's fine. We need to make + // sure it aligns with the current provided object. + if len(tbd.pending) < int(id) { + // This id was never registered. Probably an encoder error? + Failf("typeDatabase does not contain id %d", id) + } + // Extract the pending info. + pending := tbd.pending[id-1] + // Grow the byID list. + if len(tbd.byID) < int(id) { + tbd.byID = append(tbd.byID, make([]*reconciledTypeEntry, int(id)-len(tbd.byID))...) + } + // Reconcile the type. + name, fields, ok := lookupNameFields(typ) + if !ok { + // Empty structs are decoded only when the type is nil. Since + // this isn't the case, we fail here. + Failf("unsupported type %q during decode; can't reconcile", pending.Name) + } + if name != pending.Name { + // Are these the same type? Print a helpful message as this may + // actually happen in practice if types change. + Failf("typeDatabase contains conflicting definitions for id %d: %s->%v (current) and %s->%v (existing)", + id, name, fields, pending.Name, pending.Fields) + } + rte := &reconciledTypeEntry{ + Type: wire.Type{ + Name: name, + Fields: fields, + }, + LocalType: typ, + } + // If there are zero or one fields, then we skip allocating the field + // slice. There is special handling for decoding in this case. If the + // field name does not match, it will be caught in the general purpose + // code below. + if len(fields) != len(pending.Fields) { + Failf("type %q contains different fields: %v (decode) and %v (encode)", + name, fields, pending.Fields) + } + if len(fields) == 0 { + tbd.byID[id-1] = rte // Save. + return rte + } + if len(fields) == 1 && fields[0] == pending.Fields[0] { + tbd.byID[id-1] = rte // Save. + rte.FieldOrder = singleFieldOrder + return rte + } + // For each field in the current object's information, match it to a + // field in the destination object. We know from the assertion above + // and the insertion on insertion to pending that neither field + // contains any duplicates. + fieldOrder := make([]int, len(fields)) + for i, name := range fields { + fieldOrder[i] = -1 // Sentinel. + // Is it an exact match? + if pending.Fields[i] == name { + fieldOrder[i] = i + continue + } + // Find the matching field. + for j, otherName := range pending.Fields { + if name == otherName { + fieldOrder[i] = j + break + } + } + if fieldOrder[i] == -1 { + // The type name matches but we are lacking some common fields. + Failf("type %q has mismatched fields: %v (decode) and %v (encode)", + name, fields, pending.Fields) + } + } + // The type has been reeconciled. + rte.FieldOrder = fieldOrder + tbd.byID[id-1] = rte + return rte +} + +// interfaceType defines all interfaces. +const interfaceType = "interface" + +// primitiveTypeDatabase is a set of fixed types. +var primitiveTypeDatabase = func() map[string]reflect.Type { + r := make(map[string]reflect.Type) + for _, t := range []reflect.Type{ + reflect.TypeOf(false), + reflect.TypeOf(int(0)), + reflect.TypeOf(int8(0)), + reflect.TypeOf(int16(0)), + reflect.TypeOf(int32(0)), + reflect.TypeOf(int64(0)), + reflect.TypeOf(uint(0)), + reflect.TypeOf(uintptr(0)), + reflect.TypeOf(uint8(0)), + reflect.TypeOf(uint16(0)), + reflect.TypeOf(uint32(0)), + reflect.TypeOf(uint64(0)), + reflect.TypeOf(""), + reflect.TypeOf(float32(0.0)), + reflect.TypeOf(float64(0.0)), + reflect.TypeOf(complex64(0.0)), + reflect.TypeOf(complex128(0.0)), + } { + r[t.Name()] = t + } + return r +}() + +// globalTypeDatabase is used for dispatching interfaces on decode. +var globalTypeDatabase = map[string]reflect.Type{} + +// Register registers a type. +// +// This must be called on init and only done once. +func Register(t Type) { + name := t.StateTypeName() + fields := t.StateFields() + assertValidType(name, fields) + // Register must always be called on pointers. + typ := reflect.TypeOf(t) + if typ.Kind() != reflect.Ptr { + Failf("Register must be called on pointers") + } + typ = typ.Elem() + if typ.Kind() == reflect.Struct { + // All registered structs must implement SaverLoader. We allow + // the registration is non-struct types with just the Type + // interface, but we need to call StateSave/StateLoad methods + // on aggregate types. + if _, ok := t.(SaverLoader); !ok { + Failf("struct %T does not implement SaverLoader", t) + } + } else { + // Non-structs must not have any fields. We don't support + // calling StateSave/StateLoad methods on any non-struct types. + // If custom behavior is required, these types should be + // wrapped in a structure of some kind. + if len(fields) != 0 { + Failf("non-struct %T has non-zero fields %v", t, fields) + } + // We don't allow non-structs to implement StateSave/StateLoad + // methods, because they won't be called and it's confusing. + if _, ok := t.(SaverLoader); ok { + Failf("non-struct %T implements SaverLoader", t) + } + } + if _, ok := primitiveTypeDatabase[name]; ok { + Failf("conflicting primitiveTypeDatabase entry for %T: used by primitive", t) + } + if _, ok := globalTypeDatabase[name]; ok { + Failf("conflicting globalTypeDatabase entries for %T: name conflict", t) + } + if name == interfaceType { + Failf("conflicting name for %T: matches interfaceType", t) + } + globalTypeDatabase[name] = typ +} diff --git a/pkg/state/wire/BUILD b/pkg/state/wire/BUILD new file mode 100644 index 000000000..311b93dcb --- /dev/null +++ b/pkg/state/wire/BUILD @@ -0,0 +1,12 @@ +load("//tools:defs.bzl", "go_library") + +package(licenses = ["notice"]) + +go_library( + name = "wire", + srcs = ["wire.go"], + marshal = False, + stateify = False, + visibility = ["//:sandbox"], + deps = ["//pkg/gohacks"], +) diff --git a/pkg/state/wire/wire.go b/pkg/state/wire/wire.go new file mode 100644 index 000000000..93dee6740 --- /dev/null +++ b/pkg/state/wire/wire.go @@ -0,0 +1,970 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package wire contains a few basic types that can be composed to serialize +// graph information for the state package. This package defines the wire +// protocol. +// +// Note that these types are careful about how they implement the relevant +// interfaces (either value receiver or pointer receiver), so that native-sized +// types, such as integers and simple pointers, can fit inside the interface +// object. +// +// This package also uses panic as control flow, so called should be careful to +// wrap calls in appropriate handlers. +// +// Testing for this package is driven by the state test package. +package wire + +import ( + "fmt" + "io" + "math" + + "gvisor.dev/gvisor/pkg/gohacks" +) + +// Reader is the required reader interface. +type Reader interface { + io.Reader + ReadByte() (byte, error) +} + +// Writer is the required writer interface. +type Writer interface { + io.Writer + WriteByte(byte) error +} + +// readFull is a utility. The equivalent is not needed for Write, but the API +// contract dictates that it must always complete all bytes given or return an +// error. +func readFull(r io.Reader, p []byte) { + for done := 0; done < len(p); { + n, err := r.Read(p[done:]) + done += n + if n == 0 && err != nil { + panic(err) + } + } +} + +// Object is a generic object. +type Object interface { + // save saves the given object. + // + // Panic is used for error control flow. + save(Writer) + + // load loads a new object of the given type. + // + // Panic is used for error control flow. + load(Reader) Object +} + +// Bool is a boolean. +type Bool bool + +// loadBool loads an object of type Bool. +func loadBool(r Reader) Bool { + b := loadUint(r) + return Bool(b == 1) +} + +// save implements Object.save. +func (b Bool) save(w Writer) { + var v Uint + if b { + v = 1 + } else { + v = 0 + } + v.save(w) +} + +// load implements Object.load. +func (Bool) load(r Reader) Object { return loadBool(r) } + +// Int is a signed integer. +// +// This uses varint encoding. +type Int int64 + +// loadInt loads an object of type Int. +func loadInt(r Reader) Int { + u := loadUint(r) + x := Int(u >> 1) + if u&1 != 0 { + x = ^x + } + return x +} + +// save implements Object.save. +func (i Int) save(w Writer) { + u := Uint(i) << 1 + if i < 0 { + u = ^u + } + u.save(w) +} + +// load implements Object.load. +func (Int) load(r Reader) Object { return loadInt(r) } + +// Uint is an unsigned integer. +type Uint uint64 + +// loadUint loads an object of type Uint. +func loadUint(r Reader) Uint { + var ( + u Uint + s uint + ) + for i := 0; i <= 9; i++ { + b, err := r.ReadByte() + if err != nil { + panic(err) + } + if b < 0x80 { + if i == 9 && b > 1 { + panic("overflow") + } + u |= Uint(b) << s + return u + } + u |= Uint(b&0x7f) << s + s += 7 + } + panic("unreachable") +} + +// save implements Object.save. +func (u Uint) save(w Writer) { + for u >= 0x80 { + if err := w.WriteByte(byte(u) | 0x80); err != nil { + panic(err) + } + u >>= 7 + } + if err := w.WriteByte(byte(u)); err != nil { + panic(err) + } +} + +// load implements Object.load. +func (Uint) load(r Reader) Object { return loadUint(r) } + +// Float32 is a 32-bit floating point number. +type Float32 float32 + +// loadFloat32 loads an object of type Float32. +func loadFloat32(r Reader) Float32 { + n := loadUint(r) + return Float32(math.Float32frombits(uint32(n))) +} + +// save implements Object.save. +func (f Float32) save(w Writer) { + n := Uint(math.Float32bits(float32(f))) + n.save(w) +} + +// load implements Object.load. +func (Float32) load(r Reader) Object { return loadFloat32(r) } + +// Float64 is a 64-bit floating point number. +type Float64 float64 + +// loadFloat64 loads an object of type Float64. +func loadFloat64(r Reader) Float64 { + n := loadUint(r) + return Float64(math.Float64frombits(uint64(n))) +} + +// save implements Object.save. +func (f Float64) save(w Writer) { + n := Uint(math.Float64bits(float64(f))) + n.save(w) +} + +// load implements Object.load. +func (Float64) load(r Reader) Object { return loadFloat64(r) } + +// Complex64 is a 64-bit complex number. +type Complex64 complex128 + +// loadComplex64 loads an object of type Complex64. +func loadComplex64(r Reader) Complex64 { + re := loadFloat32(r) + im := loadFloat32(r) + return Complex64(complex(float32(re), float32(im))) +} + +// save implements Object.save. +func (c *Complex64) save(w Writer) { + re := Float32(real(*c)) + im := Float32(imag(*c)) + re.save(w) + im.save(w) +} + +// load implements Object.load. +func (*Complex64) load(r Reader) Object { + c := loadComplex64(r) + return &c +} + +// Complex128 is a 128-bit complex number. +type Complex128 complex128 + +// loadComplex128 loads an object of type Complex128. +func loadComplex128(r Reader) Complex128 { + re := loadFloat64(r) + im := loadFloat64(r) + return Complex128(complex(float64(re), float64(im))) +} + +// save implements Object.save. +func (c *Complex128) save(w Writer) { + re := Float64(real(*c)) + im := Float64(imag(*c)) + re.save(w) + im.save(w) +} + +// load implements Object.load. +func (*Complex128) load(r Reader) Object { + c := loadComplex128(r) + return &c +} + +// String is a string. +type String string + +// loadString loads an object of type String. +func loadString(r Reader) String { + l := loadUint(r) + p := make([]byte, l) + readFull(r, p) + return String(gohacks.StringFromImmutableBytes(p)) +} + +// save implements Object.save. +func (s *String) save(w Writer) { + l := Uint(len(*s)) + l.save(w) + p := gohacks.ImmutableBytesFromString(string(*s)) + _, err := w.Write(p) // Must write all bytes. + if err != nil { + panic(err) + } +} + +// load implements Object.load. +func (*String) load(r Reader) Object { + s := loadString(r) + return &s +} + +// Dot is a kind of reference: one of Index and FieldName. +type Dot interface { + isDot() +} + +// Index is a reference resolution. +type Index uint32 + +func (Index) isDot() {} + +// FieldName is a reference resolution. +type FieldName string + +func (*FieldName) isDot() {} + +// Ref is a reference to an object. +type Ref struct { + // Root is the root object. + Root Uint + + // Dots is the set of traversals required from the Root object above. + // Note that this will be stored in reverse order for efficiency. + Dots []Dot + + // Type is the base type for the root object. This is non-nil iff Dots + // is non-zero length (that is, this is a complex reference). This is + // not *strictly* necessary, but can be used to simplify decoding. + Type TypeSpec +} + +// loadRef loads an object of type Ref (abstract). +func loadRef(r Reader) Ref { + ref := Ref{ + Root: loadUint(r), + } + l := loadUint(r) + ref.Dots = make([]Dot, l) + for i := 0; i < int(l); i++ { + // Disambiguate between an Index (non-negative) and a field + // name (negative). This does some space and avoids a dedicate + // loadDot function. See Ref.save for the other side. + d := loadInt(r) + if d >= 0 { + ref.Dots[i] = Index(d) + continue + } + p := make([]byte, -d) + readFull(r, p) + fieldName := FieldName(gohacks.StringFromImmutableBytes(p)) + ref.Dots[i] = &fieldName + } + if l != 0 { + // Only if dots is non-zero. + ref.Type = loadTypeSpec(r) + } + return ref +} + +// save implements Object.save. +func (r *Ref) save(w Writer) { + r.Root.save(w) + l := Uint(len(r.Dots)) + l.save(w) + for _, d := range r.Dots { + // See LoadRef. We use non-negative numbers to encode Index + // objects and negative numbers to encode field lengths. + switch x := d.(type) { + case Index: + i := Int(x) + i.save(w) + case *FieldName: + d := Int(-len(*x)) + d.save(w) + p := gohacks.ImmutableBytesFromString(string(*x)) + if _, err := w.Write(p); err != nil { + panic(err) + } + default: + panic("unknown dot implementation") + } + } + if l != 0 { + // See above. + saveTypeSpec(w, r.Type) + } +} + +// load implements Object.load. +func (*Ref) load(r Reader) Object { + ref := loadRef(r) + return &ref +} + +// Nil is a primitive zero value of any type. +type Nil struct{} + +// loadNil loads an object of type Nil. +func loadNil(r Reader) Nil { + return Nil{} +} + +// save implements Object.save. +func (Nil) save(w Writer) {} + +// load implements Object.load. +func (Nil) load(r Reader) Object { return loadNil(r) } + +// Slice is a slice value. +type Slice struct { + Length Uint + Capacity Uint + Ref Ref +} + +// loadSlice loads an object of type Slice. +func loadSlice(r Reader) Slice { + return Slice{ + Length: loadUint(r), + Capacity: loadUint(r), + Ref: loadRef(r), + } +} + +// save implements Object.save. +func (s *Slice) save(w Writer) { + s.Length.save(w) + s.Capacity.save(w) + s.Ref.save(w) +} + +// load implements Object.load. +func (*Slice) load(r Reader) Object { + s := loadSlice(r) + return &s +} + +// Array is an array value. +type Array struct { + Contents []Object +} + +// loadArray loads an object of type Array. +func loadArray(r Reader) Array { + l := loadUint(r) + if l == 0 { + // Note that there isn't a single object available to encode + // the type of, so we need this additional branch. + return Array{} + } + // All the objects here have the same type, so use dynamic dispatch + // only once. All other objects will automatically take the same type + // as the first object. + contents := make([]Object, l) + v := Load(r) + contents[0] = v + for i := 1; i < int(l); i++ { + contents[i] = v.load(r) + } + return Array{ + Contents: contents, + } +} + +// save implements Object.save. +func (a *Array) save(w Writer) { + l := Uint(len(a.Contents)) + l.save(w) + if l == 0 { + // See LoadArray. + return + } + // See above. + Save(w, a.Contents[0]) + for i := 1; i < int(l); i++ { + a.Contents[i].save(w) + } +} + +// load implements Object.load. +func (*Array) load(r Reader) Object { + a := loadArray(r) + return &a +} + +// Map is a map value. +type Map struct { + Keys []Object + Values []Object +} + +// loadMap loads an object of type Map. +func loadMap(r Reader) Map { + l := loadUint(r) + if l == 0 { + // See LoadArray. + return Map{} + } + // See type dispatch notes in Array. + keys := make([]Object, l) + values := make([]Object, l) + k := Load(r) + v := Load(r) + keys[0] = k + values[0] = v + for i := 1; i < int(l); i++ { + keys[i] = k.load(r) + values[i] = v.load(r) + } + return Map{ + Keys: keys, + Values: values, + } +} + +// save implements Object.save. +func (m *Map) save(w Writer) { + l := Uint(len(m.Keys)) + if int(l) != len(m.Values) { + panic(fmt.Sprintf("mismatched keys (%d) Aand values (%d)", len(m.Keys), len(m.Values))) + } + l.save(w) + if l == 0 { + // See LoadArray. + return + } + // See above. + Save(w, m.Keys[0]) + Save(w, m.Values[0]) + for i := 1; i < int(l); i++ { + m.Keys[i].save(w) + m.Values[i].save(w) + } +} + +// load implements Object.load. +func (*Map) load(r Reader) Object { + m := loadMap(r) + return &m +} + +// TypeSpec is a type dereference. +type TypeSpec interface { + isTypeSpec() +} + +// TypeID is a concrete type ID. +type TypeID Uint + +func (TypeID) isTypeSpec() {} + +// TypeSpecPointer is a pointer type. +type TypeSpecPointer struct { + Type TypeSpec +} + +func (*TypeSpecPointer) isTypeSpec() {} + +// TypeSpecArray is an array type. +type TypeSpecArray struct { + Count Uint + Type TypeSpec +} + +func (*TypeSpecArray) isTypeSpec() {} + +// TypeSpecSlice is a slice type. +type TypeSpecSlice struct { + Type TypeSpec +} + +func (*TypeSpecSlice) isTypeSpec() {} + +// TypeSpecMap is a map type. +type TypeSpecMap struct { + Key TypeSpec + Value TypeSpec +} + +func (*TypeSpecMap) isTypeSpec() {} + +// TypeSpecNil is an empty type. +type TypeSpecNil struct{} + +func (TypeSpecNil) isTypeSpec() {} + +// TypeSpec types. +// +// These use a distinct encoding on the wire, as they are used only in the +// interface object. They are decoded through the dedicated loadTypeSpec and +// saveTypeSpec functions. +const ( + typeSpecTypeID Uint = iota + typeSpecPointer + typeSpecArray + typeSpecSlice + typeSpecMap + typeSpecNil +) + +// loadTypeSpec loads TypeSpec values. +func loadTypeSpec(r Reader) TypeSpec { + switch hdr := loadUint(r); hdr { + case typeSpecTypeID: + return TypeID(loadUint(r)) + case typeSpecPointer: + return &TypeSpecPointer{ + Type: loadTypeSpec(r), + } + case typeSpecArray: + return &TypeSpecArray{ + Count: loadUint(r), + Type: loadTypeSpec(r), + } + case typeSpecSlice: + return &TypeSpecSlice{ + Type: loadTypeSpec(r), + } + case typeSpecMap: + return &TypeSpecMap{ + Key: loadTypeSpec(r), + Value: loadTypeSpec(r), + } + case typeSpecNil: + return TypeSpecNil{} + default: + // This is not a valid stream? + panic(fmt.Errorf("unknown header: %d", hdr)) + } +} + +// saveTypeSpec saves TypeSpec values. +func saveTypeSpec(w Writer, t TypeSpec) { + switch x := t.(type) { + case TypeID: + typeSpecTypeID.save(w) + Uint(x).save(w) + case *TypeSpecPointer: + typeSpecPointer.save(w) + saveTypeSpec(w, x.Type) + case *TypeSpecArray: + typeSpecArray.save(w) + x.Count.save(w) + saveTypeSpec(w, x.Type) + case *TypeSpecSlice: + typeSpecSlice.save(w) + saveTypeSpec(w, x.Type) + case *TypeSpecMap: + typeSpecMap.save(w) + saveTypeSpec(w, x.Key) + saveTypeSpec(w, x.Value) + case TypeSpecNil: + typeSpecNil.save(w) + default: + // This should not happen? + panic(fmt.Errorf("unknown type %T", t)) + } +} + +// Interface is an interface value. +type Interface struct { + Type TypeSpec + Value Object +} + +// loadInterface loads an object of type Interface. +func loadInterface(r Reader) Interface { + return Interface{ + Type: loadTypeSpec(r), + Value: Load(r), + } +} + +// save implements Object.save. +func (i *Interface) save(w Writer) { + saveTypeSpec(w, i.Type) + Save(w, i.Value) +} + +// load implements Object.load. +func (*Interface) load(r Reader) Object { + i := loadInterface(r) + return &i +} + +// Type is type information. +type Type struct { + Name string + Fields []string +} + +// loadType loads an object of type Type. +func loadType(r Reader) Type { + name := string(loadString(r)) + l := loadUint(r) + fields := make([]string, l) + for i := 0; i < int(l); i++ { + fields[i] = string(loadString(r)) + } + return Type{ + Name: name, + Fields: fields, + } +} + +// save implements Object.save. +func (t *Type) save(w Writer) { + s := String(t.Name) + s.save(w) + l := Uint(len(t.Fields)) + l.save(w) + for i := 0; i < int(l); i++ { + s := String(t.Fields[i]) + s.save(w) + } +} + +// load implements Object.load. +func (*Type) load(r Reader) Object { + t := loadType(r) + return &t +} + +// multipleObjects is a special type for serializing multiple objects. +type multipleObjects []Object + +// loadMultipleObjects loads a series of objects. +func loadMultipleObjects(r Reader) multipleObjects { + l := loadUint(r) + m := make(multipleObjects, l) + for i := 0; i < int(l); i++ { + m[i] = Load(r) + } + return m +} + +// save implements Object.save. +func (m *multipleObjects) save(w Writer) { + l := Uint(len(*m)) + l.save(w) + for i := 0; i < int(l); i++ { + Save(w, (*m)[i]) + } +} + +// load implements Object.load. +func (*multipleObjects) load(r Reader) Object { + m := loadMultipleObjects(r) + return &m +} + +// noObjects represents no objects. +type noObjects struct{} + +// loadNoObjects loads a sentinel. +func loadNoObjects(r Reader) noObjects { return noObjects{} } + +// save implements Object.save. +func (noObjects) save(w Writer) {} + +// load implements Object.load. +func (noObjects) load(r Reader) Object { return loadNoObjects(r) } + +// Struct is a basic composite value. +type Struct struct { + TypeID TypeID + fields Object // Optionally noObjects or *multipleObjects. +} + +// Field returns a pointer to the given field slot. +// +// This must be called after Alloc. +func (s *Struct) Field(i int) *Object { + if fields, ok := s.fields.(*multipleObjects); ok { + return &((*fields)[i]) + } + if _, ok := s.fields.(noObjects); ok { + // Alloc may be optionally called; can't call twice. + panic("Field called inappropriately, wrong Alloc?") + } + return &s.fields +} + +// Alloc allocates the given number of fields. +// +// This must be called before Add and Save. +// +// Precondition: slots must be positive. +func (s *Struct) Alloc(slots int) { + switch { + case slots == 0: + s.fields = noObjects{} + case slots == 1: + // Leave it alone. + case slots > 1: + fields := make(multipleObjects, slots) + s.fields = &fields + default: + // Violates precondition. + panic(fmt.Sprintf("Alloc called with negative slots %d?", slots)) + } +} + +// Fields returns the number of fields. +func (s *Struct) Fields() int { + switch x := s.fields.(type) { + case *multipleObjects: + return len(*x) + case noObjects: + return 0 + default: + return 1 + } +} + +// loadStruct loads an object of type Struct. +func loadStruct(r Reader) Struct { + return Struct{ + TypeID: TypeID(loadUint(r)), + fields: Load(r), + } +} + +// save implements Object.save. +// +// Precondition: Alloc must have been called, and the fields all filled in +// appropriately. See Alloc and Add for more details. +func (s *Struct) save(w Writer) { + Uint(s.TypeID).save(w) + Save(w, s.fields) +} + +// load implements Object.load. +func (*Struct) load(r Reader) Object { + s := loadStruct(r) + return &s +} + +// Object types. +// +// N.B. Be careful about changing the order or introducing new elements in the +// middle here. This is part of the wire format and shouldn't change. +const ( + typeBool Uint = iota + typeInt + typeUint + typeFloat32 + typeFloat64 + typeNil + typeRef + typeString + typeSlice + typeArray + typeMap + typeStruct + typeNoObjects + typeMultipleObjects + typeInterface + typeComplex64 + typeComplex128 + typeType +) + +// Save saves the given object. +// +// +checkescape all +// +// N.B. This function will panic on error. +func Save(w Writer, obj Object) { + switch x := obj.(type) { + case Bool: + typeBool.save(w) + x.save(w) + case Int: + typeInt.save(w) + x.save(w) + case Uint: + typeUint.save(w) + x.save(w) + case Float32: + typeFloat32.save(w) + x.save(w) + case Float64: + typeFloat64.save(w) + x.save(w) + case Nil: + typeNil.save(w) + x.save(w) + case *Ref: + typeRef.save(w) + x.save(w) + case *String: + typeString.save(w) + x.save(w) + case *Slice: + typeSlice.save(w) + x.save(w) + case *Array: + typeArray.save(w) + x.save(w) + case *Map: + typeMap.save(w) + x.save(w) + case *Struct: + typeStruct.save(w) + x.save(w) + case noObjects: + typeNoObjects.save(w) + x.save(w) + case *multipleObjects: + typeMultipleObjects.save(w) + x.save(w) + case *Interface: + typeInterface.save(w) + x.save(w) + case *Type: + typeType.save(w) + x.save(w) + case *Complex64: + typeComplex64.save(w) + x.save(w) + case *Complex128: + typeComplex128.save(w) + x.save(w) + default: + panic(fmt.Errorf("unknown type: %#v", obj)) + } +} + +// Load loads a new object. +// +// +checkescape all +// +// N.B. This function will panic on error. +func Load(r Reader) Object { + switch hdr := loadUint(r); hdr { + case typeBool: + return loadBool(r) + case typeInt: + return loadInt(r) + case typeUint: + return loadUint(r) + case typeFloat32: + return loadFloat32(r) + case typeFloat64: + return loadFloat64(r) + case typeNil: + return loadNil(r) + case typeRef: + return ((*Ref)(nil)).load(r) // Escapes. + case typeString: + return ((*String)(nil)).load(r) // Escapes. + case typeSlice: + return ((*Slice)(nil)).load(r) // Escapes. + case typeArray: + return ((*Array)(nil)).load(r) // Escapes. + case typeMap: + return ((*Map)(nil)).load(r) // Escapes. + case typeStruct: + return ((*Struct)(nil)).load(r) // Escapes. + case typeNoObjects: // Special for struct. + return loadNoObjects(r) + case typeMultipleObjects: // Special for struct. + return ((*multipleObjects)(nil)).load(r) // Escapes. + case typeInterface: + return ((*Interface)(nil)).load(r) // Escapes. + case typeComplex64: + return ((*Complex64)(nil)).load(r) // Escapes. + case typeComplex128: + return ((*Complex128)(nil)).load(r) // Escapes. + case typeType: + return ((*Type)(nil)).load(r) // Escapes. + default: + // This is not a valid stream? + panic(fmt.Errorf("unknown header: %d", hdr)) + } +} + +// LoadUint loads a single unsigned integer. +// +// N.B. This function will panic on error. +func LoadUint(r Reader) uint64 { + return uint64(loadUint(r)) +} + +// SaveUint saves a single unsigned integer. +// +// N.B. This function will panic on error. +func SaveUint(w Writer, v uint64) { + Uint(v).save(w) +} |