From 0e2f1b7abd219f39d67cc2cecd00c441a13eeb29 Mon Sep 17 00:00:00 2001 From: Adin Scannell Date: Mon, 27 Jan 2020 15:17:58 -0800 Subject: Update package locations. Because the abi will depend on the core types for marshalling (usermem, context, safemem, safecopy), these need to be flattened from the sentry directory. These packages contain no sentry-specific details. PiperOrigin-RevId: 291811289 --- pkg/context/context.go | 141 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 pkg/context/context.go (limited to 'pkg/context/context.go') diff --git a/pkg/context/context.go b/pkg/context/context.go new file mode 100644 index 000000000..23e009ef3 --- /dev/null +++ b/pkg/context/context.go @@ -0,0 +1,141 @@ +// 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 context defines an internal context type. +// +// The given Context conforms to the standard Go context, but mandates +// additional methods that are specific to the kernel internals. Note however, +// that the Context described by this package carries additional constraints +// regarding concurrent access and retaining beyond the scope of a call. +// +// See the Context type for complete details. +package context + +import ( + "context" + "time" + + "gvisor.dev/gvisor/pkg/amutex" + "gvisor.dev/gvisor/pkg/log" +) + +type contextID int + +// Globally accessible values from a context. These keys are defined in the +// context package to resolve dependency cycles by not requiring the caller to +// import packages usually required to get these information. +const ( + // CtxThreadGroupID is the current thread group ID when a context represents + // a task context. The value is represented as an int32. + CtxThreadGroupID contextID = iota +) + +// ThreadGroupIDFromContext returns the current thread group ID when ctx +// represents a task context. +func ThreadGroupIDFromContext(ctx Context) (tgid int32, ok bool) { + if tgid := ctx.Value(CtxThreadGroupID); tgid != nil { + return tgid.(int32), true + } + return 0, false +} + +// A Context represents a thread of execution (hereafter "goroutine" to reflect +// Go idiosyncrasy). It carries state associated with the goroutine across API +// boundaries. +// +// While Context exists for essentially the same reasons as Go's standard +// context.Context, the standard type represents the state of an operation +// rather than that of a goroutine. This is a critical distinction: +// +// - Unlike context.Context, which "may be passed to functions running in +// different goroutines", it is *not safe* to use the same Context in multiple +// concurrent goroutines. +// +// - It is *not safe* to retain a Context passed to a function beyond the scope +// of that function call. +// +// In both cases, values extracted from the Context should be used instead. +type Context interface { + log.Logger + amutex.Sleeper + context.Context + + // UninterruptibleSleepStart indicates the beginning of an uninterruptible + // sleep state (equivalent to Linux's TASK_UNINTERRUPTIBLE). If deactivate + // is true and the Context represents a Task, the Task's AddressSpace is + // deactivated. + UninterruptibleSleepStart(deactivate bool) + + // UninterruptibleSleepFinish indicates the end of an uninterruptible sleep + // state that was begun by a previous call to UninterruptibleSleepStart. If + // activate is true and the Context represents a Task, the Task's + // AddressSpace is activated. Normally activate is the same value as the + // deactivate parameter passed to UninterruptibleSleepStart. + UninterruptibleSleepFinish(activate bool) +} + +// NoopSleeper is a noop implementation of amutex.Sleeper and UninterruptibleSleep +// methods for anonymous embedding in other types that do not implement sleeps. +type NoopSleeper struct { + amutex.NoopSleeper +} + +// UninterruptibleSleepStart does nothing. +func (NoopSleeper) UninterruptibleSleepStart(bool) {} + +// UninterruptibleSleepFinish does nothing. +func (NoopSleeper) UninterruptibleSleepFinish(bool) {} + +// Deadline returns zero values, meaning no deadline. +func (NoopSleeper) Deadline() (time.Time, bool) { + return time.Time{}, false +} + +// Done returns nil. +func (NoopSleeper) Done() <-chan struct{} { + return nil +} + +// Err returns nil. +func (NoopSleeper) Err() error { + return nil +} + +// logContext implements basic logging. +type logContext struct { + log.Logger + NoopSleeper +} + +// Value implements Context.Value. +func (logContext) Value(key interface{}) interface{} { + return nil +} + +// bgContext is the context returned by context.Background. +var bgContext = &logContext{Logger: log.Log()} + +// Background returns an empty context using the default logger. +// +// Users should be wary of using a Background context. Please tag any use with +// FIXME(b/38173783) and a note to remove this use. +// +// Generally, one should use the Task as their context when available, or avoid +// having to use a context in places where a Task is unavailable. +// +// Using a Background context for tests is fine, as long as no values are +// needed from the context in the tested code paths. +func Background() Context { + return bgContext +} -- cgit v1.2.3 From 6a4d17a31dc209afbbca66e871a7c6dc299c167b Mon Sep 17 00:00:00 2001 From: Jon Budd Date: Mon, 13 Apr 2020 11:01:02 -0700 Subject: Remove obsolete TODOs for b/38173783 The comments in the ticket indicate that this behavior is fine and that the ticket should be closed, so we shouldn't need pointers to the ticket. PiperOrigin-RevId: 306266071 --- pkg/context/context.go | 4 ---- pkg/sentry/arch/stack.go | 3 --- pkg/sentry/fs/gofer/file_state.go | 1 - pkg/sentry/fs/gofer/handles.go | 1 - pkg/sentry/fs/gofer/inode_state.go | 1 - pkg/sentry/fs/gofer/session_state.go | 1 - pkg/sentry/fs/inode.go | 1 - pkg/sentry/kernel/shm/shm.go | 2 +- pkg/sentry/kernel/task_context.go | 1 - pkg/sentry/kernel/task_signals.go | 2 -- pkg/usermem/usermem.go | 3 --- 11 files changed, 1 insertion(+), 19 deletions(-) (limited to 'pkg/context/context.go') diff --git a/pkg/context/context.go b/pkg/context/context.go index 23e009ef3..5319b6d8d 100644 --- a/pkg/context/context.go +++ b/pkg/context/context.go @@ -127,10 +127,6 @@ func (logContext) Value(key interface{}) interface{} { var bgContext = &logContext{Logger: log.Log()} // Background returns an empty context using the default logger. -// -// Users should be wary of using a Background context. Please tag any use with -// FIXME(b/38173783) and a note to remove this use. -// // Generally, one should use the Task as their context when available, or avoid // having to use a context in places where a Task is unavailable. // diff --git a/pkg/sentry/arch/stack.go b/pkg/sentry/arch/stack.go index 09bceabc9..1108fa0bd 100644 --- a/pkg/sentry/arch/stack.go +++ b/pkg/sentry/arch/stack.go @@ -97,7 +97,6 @@ func (s *Stack) Push(vals ...interface{}) (usermem.Addr, error) { if c < 0 { return 0, fmt.Errorf("bad binary.Size for %T", v) } - // TODO(b/38173783): Use a real context.Context. n, err := usermem.CopyObjectOut(context.Background(), s.IO, s.Bottom-usermem.Addr(c), norm, usermem.IOOpts{}) if err != nil || c != n { return 0, err @@ -121,11 +120,9 @@ func (s *Stack) Pop(vals ...interface{}) (usermem.Addr, error) { var err error if isVaddr { value := s.Arch.Native(uintptr(0)) - // TODO(b/38173783): Use a real context.Context. n, err = usermem.CopyObjectIn(context.Background(), s.IO, s.Bottom, value, usermem.IOOpts{}) *vaddr = usermem.Addr(s.Arch.Value(value)) } else { - // TODO(b/38173783): Use a real context.Context. n, err = usermem.CopyObjectIn(context.Background(), s.IO, s.Bottom, v, usermem.IOOpts{}) } if err != nil { diff --git a/pkg/sentry/fs/gofer/file_state.go b/pkg/sentry/fs/gofer/file_state.go index ff96b28ba..edd6576aa 100644 --- a/pkg/sentry/fs/gofer/file_state.go +++ b/pkg/sentry/fs/gofer/file_state.go @@ -34,7 +34,6 @@ func (f *fileOperations) afterLoad() { flags := f.flags flags.Truncate = false - // TODO(b/38173783): Context is not plumbed to save/restore. f.handles, err = f.inodeOperations.fileState.getHandles(context.Background(), flags, f.inodeOperations.cachingInodeOps) if err != nil { return fmt.Errorf("failed to re-open handle: %v", err) diff --git a/pkg/sentry/fs/gofer/handles.go b/pkg/sentry/fs/gofer/handles.go index 9f7c3e89f..fc14249be 100644 --- a/pkg/sentry/fs/gofer/handles.go +++ b/pkg/sentry/fs/gofer/handles.go @@ -57,7 +57,6 @@ func (h *handles) DecRef() { } } } - // FIXME(b/38173783): Context is not plumbed here. if err := h.File.close(context.Background()); err != nil { log.Warningf("error closing p9 file: %v", err) } diff --git a/pkg/sentry/fs/gofer/inode_state.go b/pkg/sentry/fs/gofer/inode_state.go index 238f7804c..a3402e343 100644 --- a/pkg/sentry/fs/gofer/inode_state.go +++ b/pkg/sentry/fs/gofer/inode_state.go @@ -123,7 +123,6 @@ func (i *inodeFileState) afterLoad() { // beforeSave. return fmt.Errorf("failed to find path for inode number %d. Device %s contains %s", i.sattr.InodeID, i.s.connID, fs.InodeMappings(i.s.inodeMappings)) } - // TODO(b/38173783): Context is not plumbed to save/restore. ctx := &dummyClockContext{context.Background()} _, i.file, err = i.s.attach.walk(ctx, splitAbsolutePath(name)) diff --git a/pkg/sentry/fs/gofer/session_state.go b/pkg/sentry/fs/gofer/session_state.go index 111da59f9..2d398b753 100644 --- a/pkg/sentry/fs/gofer/session_state.go +++ b/pkg/sentry/fs/gofer/session_state.go @@ -104,7 +104,6 @@ func (s *session) afterLoad() { // If private unix sockets are enabled, create and fill the session's endpoint // maps. if opts.privateunixsocket { - // TODO(b/38173783): Context is not plumbed to save/restore. ctx := &dummyClockContext{context.Background()} if err = s.restoreEndpointMaps(ctx); err != nil { diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go index 73f89abcc..a34fbc946 100644 --- a/pkg/sentry/fs/inode.go +++ b/pkg/sentry/fs/inode.go @@ -102,7 +102,6 @@ func (i *Inode) DecRef() { // destroy releases the Inode and releases the msrc reference taken. func (i *Inode) destroy() { - // FIXME(b/38173783): Context is not plumbed here. ctx := context.Background() if err := i.WriteOut(ctx); err != nil { // FIXME(b/65209558): Mark as warning again once noatime is diff --git a/pkg/sentry/kernel/shm/shm.go b/pkg/sentry/kernel/shm/shm.go index 208569057..f66cfcc7f 100644 --- a/pkg/sentry/kernel/shm/shm.go +++ b/pkg/sentry/kernel/shm/shm.go @@ -461,7 +461,7 @@ func (s *Shm) AddMapping(ctx context.Context, _ memmap.MappingSpace, _ usermem.A func (s *Shm) RemoveMapping(ctx context.Context, _ memmap.MappingSpace, _ usermem.AddrRange, _ uint64, _ bool) { s.mu.Lock() defer s.mu.Unlock() - // TODO(b/38173783): RemoveMapping may be called during task exit, when ctx + // RemoveMapping may be called during task exit, when ctx // is context.Background. Gracefully handle missing clocks. Failing to // update the detach time in these cases is ok, since no one can observe the // omission. diff --git a/pkg/sentry/kernel/task_context.go b/pkg/sentry/kernel/task_context.go index c115e8d1f..9fa528384 100644 --- a/pkg/sentry/kernel/task_context.go +++ b/pkg/sentry/kernel/task_context.go @@ -58,7 +58,6 @@ func (tc *TaskContext) release() { // Nil out pointers so that if the task is saved after release, it doesn't // follow the pointers to possibly now-invalid objects. if tc.MemoryManager != nil { - // TODO(b/38173783) tc.MemoryManager.DecUsers(context.Background()) tc.MemoryManager = nil } diff --git a/pkg/sentry/kernel/task_signals.go b/pkg/sentry/kernel/task_signals.go index 8802db142..6aa798346 100644 --- a/pkg/sentry/kernel/task_signals.go +++ b/pkg/sentry/kernel/task_signals.go @@ -513,8 +513,6 @@ func (t *Task) canReceiveSignalLocked(sig linux.Signal) bool { if t.stop != nil { return false } - // - TODO(b/38173783): No special case for when t is also the sending task, - // because the identity of the sender is unknown. // - Do not choose tasks that have already been interrupted, as they may be // busy handling another signal. if len(t.interruptChan) != 0 { diff --git a/pkg/usermem/usermem.go b/pkg/usermem/usermem.go index d2f4403b0..cd6a0ea6b 100644 --- a/pkg/usermem/usermem.go +++ b/pkg/usermem/usermem.go @@ -29,9 +29,6 @@ import ( ) // IO provides access to the contents of a virtual memory space. -// -// FIXME(b/38173783): Implementations of IO cannot expect ctx to contain any -// meaningful data. type IO interface { // CopyOut copies len(src) bytes from src to the memory mapped at addr. It // returns the number of bytes copied. If the number of bytes copied is < -- cgit v1.2.3