summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/fsimpl/host
diff options
context:
space:
mode:
Diffstat (limited to 'pkg/sentry/fsimpl/host')
-rw-r--r--pkg/sentry/fsimpl/host/BUILD78
-rw-r--r--pkg/sentry/fsimpl/host/connected_endpoint_refs.go118
-rw-r--r--pkg/sentry/fsimpl/host/host_state_autogen.go91
-rw-r--r--pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go3
-rw-r--r--pkg/sentry/fsimpl/host/inode_refs.go118
5 files changed, 330 insertions, 78 deletions
diff --git a/pkg/sentry/fsimpl/host/BUILD b/pkg/sentry/fsimpl/host/BUILD
deleted file mode 100644
index 56bcf9bdb..000000000
--- a/pkg/sentry/fsimpl/host/BUILD
+++ /dev/null
@@ -1,78 +0,0 @@
-load("//tools:defs.bzl", "go_library")
-load("//tools/go_generics:defs.bzl", "go_template_instance")
-
-licenses(["notice"])
-
-go_template_instance(
- name = "inode_refs",
- out = "inode_refs.go",
- package = "host",
- prefix = "inode",
- template = "//pkg/refs_vfs2:refs_template",
- types = {
- "T": "inode",
- },
-)
-
-go_template_instance(
- name = "connected_endpoint_refs",
- out = "connected_endpoint_refs.go",
- package = "host",
- prefix = "ConnectedEndpoint",
- template = "//pkg/refs_vfs2:refs_template",
- types = {
- "T": "ConnectedEndpoint",
- },
-)
-
-go_library(
- name = "host",
- srcs = [
- "connected_endpoint_refs.go",
- "control.go",
- "host.go",
- "inode_refs.go",
- "ioctl_unsafe.go",
- "mmap.go",
- "socket.go",
- "socket_iovec.go",
- "socket_unsafe.go",
- "tty.go",
- "util.go",
- "util_unsafe.go",
- ],
- visibility = ["//pkg/sentry:internal"],
- deps = [
- "//pkg/abi/linux",
- "//pkg/context",
- "//pkg/fdnotifier",
- "//pkg/fspath",
- "//pkg/iovec",
- "//pkg/log",
- "//pkg/marshal/primitive",
- "//pkg/refs",
- "//pkg/safemem",
- "//pkg/sentry/arch",
- "//pkg/sentry/fs/fsutil",
- "//pkg/sentry/fs/lock",
- "//pkg/sentry/fsimpl/kernfs",
- "//pkg/sentry/hostfd",
- "//pkg/sentry/kernel",
- "//pkg/sentry/kernel/auth",
- "//pkg/sentry/memmap",
- "//pkg/sentry/socket/control",
- "//pkg/sentry/socket/unix",
- "//pkg/sentry/socket/unix/transport",
- "//pkg/sentry/unimpl",
- "//pkg/sentry/uniqueid",
- "//pkg/sentry/vfs",
- "//pkg/sync",
- "//pkg/syserr",
- "//pkg/syserror",
- "//pkg/tcpip",
- "//pkg/unet",
- "//pkg/usermem",
- "//pkg/waiter",
- "@org_golang_x_sys//unix:go_default_library",
- ],
-)
diff --git a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
new file mode 100644
index 000000000..7fa5a516d
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
@@ -0,0 +1,118 @@
+package host
+
+import (
+ "fmt"
+ refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
+ "runtime"
+ "sync/atomic"
+
+ "gvisor.dev/gvisor/pkg/log"
+)
+
+// ownerType is used to customize logging. Note that we use a pointer to T so
+// that we do not copy the entire object when passed as a format parameter.
+var ConnectedEndpointownerType *ConnectedEndpoint
+
+// Refs implements refs.RefCounter. It keeps a reference count using atomic
+// operations and calls the destructor when the count reaches zero.
+//
+// Note that the number of references is actually refCount + 1 so that a default
+// zero-value Refs object contains one reference.
+//
+// TODO(gvisor.dev/issue/1486): Store stack traces when leak check is enabled in
+// a map with 16-bit hashes, and store the hash in the top 16 bits of refCount.
+// This will allow us to add stack trace information to the leak messages
+// without growing the size of Refs.
+//
+// +stateify savable
+type ConnectedEndpointRefs struct {
+ // refCount is composed of two fields:
+ //
+ // [32-bit speculative references]:[32-bit real references]
+ //
+ // Speculative references are used for TryIncRef, to avoid a CompareAndSwap
+ // loop. See IncRef, DecRef and TryIncRef for details of how these fields are
+ // used.
+ refCount int64
+}
+
+func (r *ConnectedEndpointRefs) finalize() {
+ var note string
+ switch refs_vfs1.GetLeakMode() {
+ case refs_vfs1.NoLeakChecking:
+ return
+ case refs_vfs1.UninitializedLeakChecking:
+ note = "(Leak checker uninitialized): "
+ }
+ if n := r.ReadRefs(); n != 0 {
+ log.Warningf("%sRefs %p owned by %T garbage collected with ref count of %d (want 0)", note, r, ConnectedEndpointownerType, n)
+ }
+}
+
+// EnableLeakCheck checks for reference leaks when Refs gets garbage collected.
+func (r *ConnectedEndpointRefs) EnableLeakCheck() {
+ if refs_vfs1.GetLeakMode() != refs_vfs1.NoLeakChecking {
+ runtime.SetFinalizer(r, (*ConnectedEndpointRefs).finalize)
+ }
+}
+
+// ReadRefs returns the current number of references. The returned count is
+// inherently racy and is unsafe to use without external synchronization.
+func (r *ConnectedEndpointRefs) ReadRefs() int64 {
+
+ return atomic.LoadInt64(&r.refCount) + 1
+}
+
+// IncRef implements refs.RefCounter.IncRef.
+//
+//go:nosplit
+func (r *ConnectedEndpointRefs) IncRef() {
+ if v := atomic.AddInt64(&r.refCount, 1); v <= 0 {
+ panic(fmt.Sprintf("Incrementing non-positive ref count %p owned by %T", r, ConnectedEndpointownerType))
+ }
+}
+
+// TryIncRef implements refs.RefCounter.TryIncRef.
+//
+// To do this safely without a loop, a speculative reference is first acquired
+// on the object. This allows multiple concurrent TryIncRef calls to distinguish
+// other TryIncRef calls from genuine references held.
+//
+//go:nosplit
+func (r *ConnectedEndpointRefs) TryIncRef() bool {
+ const speculativeRef = 1 << 32
+ v := atomic.AddInt64(&r.refCount, speculativeRef)
+ if int32(v) < 0 {
+
+ atomic.AddInt64(&r.refCount, -speculativeRef)
+ return false
+ }
+
+ atomic.AddInt64(&r.refCount, -speculativeRef+1)
+ return true
+}
+
+// DecRef implements refs.RefCounter.DecRef.
+//
+// Note that speculative references are counted here. Since they were added
+// prior to real references reaching zero, they will successfully convert to
+// real references. In other words, we see speculative references only in the
+// following case:
+//
+// A: TryIncRef [speculative increase => sees non-negative references]
+// B: DecRef [real decrease]
+// A: TryIncRef [transform speculative to real]
+//
+//go:nosplit
+func (r *ConnectedEndpointRefs) DecRef(destroy func()) {
+ switch v := atomic.AddInt64(&r.refCount, -1); {
+ case v < -1:
+ panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %T", r, ConnectedEndpointownerType))
+
+ case v == -1:
+
+ if destroy != nil {
+ destroy()
+ }
+ }
+}
diff --git a/pkg/sentry/fsimpl/host/host_state_autogen.go b/pkg/sentry/fsimpl/host/host_state_autogen.go
new file mode 100644
index 000000000..400320c78
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/host_state_autogen.go
@@ -0,0 +1,91 @@
+// automatically generated by stateify.
+
+package host
+
+import (
+ "gvisor.dev/gvisor/pkg/state"
+)
+
+func (x *ConnectedEndpointRefs) StateTypeName() string {
+ return "pkg/sentry/fsimpl/host.ConnectedEndpointRefs"
+}
+
+func (x *ConnectedEndpointRefs) StateFields() []string {
+ return []string{
+ "refCount",
+ }
+}
+
+func (x *ConnectedEndpointRefs) beforeSave() {}
+
+func (x *ConnectedEndpointRefs) StateSave(m state.Sink) {
+ x.beforeSave()
+ m.Save(0, &x.refCount)
+}
+
+func (x *ConnectedEndpointRefs) afterLoad() {}
+
+func (x *ConnectedEndpointRefs) StateLoad(m state.Source) {
+ m.Load(0, &x.refCount)
+}
+
+func (x *inodeRefs) StateTypeName() string {
+ return "pkg/sentry/fsimpl/host.inodeRefs"
+}
+
+func (x *inodeRefs) StateFields() []string {
+ return []string{
+ "refCount",
+ }
+}
+
+func (x *inodeRefs) beforeSave() {}
+
+func (x *inodeRefs) StateSave(m state.Sink) {
+ x.beforeSave()
+ m.Save(0, &x.refCount)
+}
+
+func (x *inodeRefs) afterLoad() {}
+
+func (x *inodeRefs) StateLoad(m state.Source) {
+ m.Load(0, &x.refCount)
+}
+
+func (x *ConnectedEndpoint) StateTypeName() string {
+ return "pkg/sentry/fsimpl/host.ConnectedEndpoint"
+}
+
+func (x *ConnectedEndpoint) StateFields() []string {
+ return []string{
+ "ConnectedEndpointRefs",
+ "fd",
+ "addr",
+ "stype",
+ }
+}
+
+func (x *ConnectedEndpoint) beforeSave() {}
+
+func (x *ConnectedEndpoint) StateSave(m state.Sink) {
+ x.beforeSave()
+ m.Save(0, &x.ConnectedEndpointRefs)
+ m.Save(1, &x.fd)
+ m.Save(2, &x.addr)
+ m.Save(3, &x.stype)
+}
+
+func (x *ConnectedEndpoint) afterLoad() {}
+
+func (x *ConnectedEndpoint) StateLoad(m state.Source) {
+ m.Load(0, &x.ConnectedEndpointRefs)
+ m.Load(1, &x.fd)
+ m.Load(2, &x.addr)
+ m.Load(3, &x.stype)
+}
+
+func init() {
+ state.Register((*ConnectedEndpointRefs)(nil))
+ state.Register((*inodeRefs)(nil))
+ state.Register((*ConnectedEndpoint)(nil))
+}
diff --git a/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go b/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go
new file mode 100644
index 000000000..b2d8c661f
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go
@@ -0,0 +1,3 @@
+// automatically generated by stateify.
+
+package host
diff --git a/pkg/sentry/fsimpl/host/inode_refs.go b/pkg/sentry/fsimpl/host/inode_refs.go
new file mode 100644
index 000000000..c294b8b80
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/inode_refs.go
@@ -0,0 +1,118 @@
+package host
+
+import (
+ "fmt"
+ refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
+ "runtime"
+ "sync/atomic"
+
+ "gvisor.dev/gvisor/pkg/log"
+)
+
+// ownerType is used to customize logging. Note that we use a pointer to T so
+// that we do not copy the entire object when passed as a format parameter.
+var inodeownerType *inode
+
+// Refs implements refs.RefCounter. It keeps a reference count using atomic
+// operations and calls the destructor when the count reaches zero.
+//
+// Note that the number of references is actually refCount + 1 so that a default
+// zero-value Refs object contains one reference.
+//
+// TODO(gvisor.dev/issue/1486): Store stack traces when leak check is enabled in
+// a map with 16-bit hashes, and store the hash in the top 16 bits of refCount.
+// This will allow us to add stack trace information to the leak messages
+// without growing the size of Refs.
+//
+// +stateify savable
+type inodeRefs struct {
+ // refCount is composed of two fields:
+ //
+ // [32-bit speculative references]:[32-bit real references]
+ //
+ // Speculative references are used for TryIncRef, to avoid a CompareAndSwap
+ // loop. See IncRef, DecRef and TryIncRef for details of how these fields are
+ // used.
+ refCount int64
+}
+
+func (r *inodeRefs) finalize() {
+ var note string
+ switch refs_vfs1.GetLeakMode() {
+ case refs_vfs1.NoLeakChecking:
+ return
+ case refs_vfs1.UninitializedLeakChecking:
+ note = "(Leak checker uninitialized): "
+ }
+ if n := r.ReadRefs(); n != 0 {
+ log.Warningf("%sRefs %p owned by %T garbage collected with ref count of %d (want 0)", note, r, inodeownerType, n)
+ }
+}
+
+// EnableLeakCheck checks for reference leaks when Refs gets garbage collected.
+func (r *inodeRefs) EnableLeakCheck() {
+ if refs_vfs1.GetLeakMode() != refs_vfs1.NoLeakChecking {
+ runtime.SetFinalizer(r, (*inodeRefs).finalize)
+ }
+}
+
+// ReadRefs returns the current number of references. The returned count is
+// inherently racy and is unsafe to use without external synchronization.
+func (r *inodeRefs) ReadRefs() int64 {
+
+ return atomic.LoadInt64(&r.refCount) + 1
+}
+
+// IncRef implements refs.RefCounter.IncRef.
+//
+//go:nosplit
+func (r *inodeRefs) IncRef() {
+ if v := atomic.AddInt64(&r.refCount, 1); v <= 0 {
+ panic(fmt.Sprintf("Incrementing non-positive ref count %p owned by %T", r, inodeownerType))
+ }
+}
+
+// TryIncRef implements refs.RefCounter.TryIncRef.
+//
+// To do this safely without a loop, a speculative reference is first acquired
+// on the object. This allows multiple concurrent TryIncRef calls to distinguish
+// other TryIncRef calls from genuine references held.
+//
+//go:nosplit
+func (r *inodeRefs) TryIncRef() bool {
+ const speculativeRef = 1 << 32
+ v := atomic.AddInt64(&r.refCount, speculativeRef)
+ if int32(v) < 0 {
+
+ atomic.AddInt64(&r.refCount, -speculativeRef)
+ return false
+ }
+
+ atomic.AddInt64(&r.refCount, -speculativeRef+1)
+ return true
+}
+
+// DecRef implements refs.RefCounter.DecRef.
+//
+// Note that speculative references are counted here. Since they were added
+// prior to real references reaching zero, they will successfully convert to
+// real references. In other words, we see speculative references only in the
+// following case:
+//
+// A: TryIncRef [speculative increase => sees non-negative references]
+// B: DecRef [real decrease]
+// A: TryIncRef [transform speculative to real]
+//
+//go:nosplit
+func (r *inodeRefs) DecRef(destroy func()) {
+ switch v := atomic.AddInt64(&r.refCount, -1); {
+ case v < -1:
+ panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %T", r, inodeownerType))
+
+ case v == -1:
+
+ if destroy != nil {
+ destroy()
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 11:40:30 +0000