1 files changed, 189 insertions, 0 deletions
diff --git a/pkg/sentry/kernel/task_context.go b/pkg/sentry/kernel/task_context.go
new file mode 100644
index 000000000..70b0699dc
--- /dev/null
+++ b/pkg/sentry/kernel/task_context.go
@@ -0,0 +1,189 @@
+// 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 kernel
+
+import (
+	"time"
+
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sentry/fs"
+	"gvisor.dev/gvisor/pkg/sentry/inet"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
+	"gvisor.dev/gvisor/pkg/sentry/limits"
+	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
+	"gvisor.dev/gvisor/pkg/sentry/platform"
+	"gvisor.dev/gvisor/pkg/sentry/unimpl"
+	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
+)
+
+// Deadline implements context.Context.Deadline.
+func (t *Task) Deadline() (time.Time, bool) {
+	return time.Time{}, false
+}
+
+// Done implements context.Context.Done.
+func (t *Task) Done() <-chan struct{} {
+	return nil
+}
+
+// Err implements context.Context.Err.
+func (t *Task) Err() error {
+	return nil
+}
+
+// Value implements context.Context.Value.
+//
+// Preconditions: The caller must be running on the task goroutine.
+func (t *Task) Value(key interface{}) interface{} {
+	// This function is very hot; skip this check outside of +race builds.
+	if sync.RaceEnabled {
+		t.assertTaskGoroutine()
+	}
+	return t.contextValue(key, true /* isTaskGoroutine */)
+}
+
+func (t *Task) contextValue(key interface{}, isTaskGoroutine bool) interface{} {
+	switch key {
+	case CtxCanTrace:
+		return t.CanTrace
+	case CtxKernel:
+		return t.k
+	case CtxPIDNamespace:
+		return t.tg.pidns
+	case CtxUTSNamespace:
+		if !isTaskGoroutine {
+			t.mu.Lock()
+			defer t.mu.Unlock()
+		}
+		return t.utsns
+	case CtxIPCNamespace:
+		if !isTaskGoroutine {
+			t.mu.Lock()
+			defer t.mu.Unlock()
+		}
+		ipcns := t.ipcns
+		ipcns.IncRef()
+		return ipcns
+	case CtxTask:
+		return t
+	case auth.CtxCredentials:
+		return t.creds.Load()
+	case context.CtxThreadGroupID:
+		return int32(t.tg.ID())
+	case fs.CtxRoot:
+		if !isTaskGoroutine {
+			t.mu.Lock()
+			defer t.mu.Unlock()
+		}
+		return t.fsContext.RootDirectory()
+	case vfs.CtxRoot:
+		if !isTaskGoroutine {
+			t.mu.Lock()
+			defer t.mu.Unlock()
+		}
+		return t.fsContext.RootDirectoryVFS2()
+	case vfs.CtxMountNamespace:
+		if !isTaskGoroutine {
+			t.mu.Lock()
+			defer t.mu.Unlock()
+		}
+		t.mountNamespaceVFS2.IncRef()
+		return t.mountNamespaceVFS2
+	case fs.CtxDirentCacheLimiter:
+		return t.k.DirentCacheLimiter
+	case inet.CtxStack:
+		return t.NetworkContext()
+	case ktime.CtxRealtimeClock:
+		return t.k.RealtimeClock()
+	case limits.CtxLimits:
+		return t.tg.limits
+	case pgalloc.CtxMemoryFile:
+		return t.k.mf
+	case pgalloc.CtxMemoryFileProvider:
+		return t.k
+	case platform.CtxPlatform:
+		return t.k
+	case uniqueid.CtxGlobalUniqueID:
+		return t.k.UniqueID()
+	case uniqueid.CtxGlobalUniqueIDProvider:
+		return t.k
+	case uniqueid.CtxInotifyCookie:
+		return t.k.GenerateInotifyCookie()
+	case unimpl.CtxEvents:
+		return t.k
+	default:
+		return nil
+	}
+}
+
+// taskAsyncContext implements context.Context for a goroutine that performs
+// work on behalf of a Task, but is not the task goroutine.
+type taskAsyncContext struct {
+	context.NoopSleeper
+
+	t *Task
+}
+
+// AsyncContext returns a context.Context representing t. The returned
+// context.Context is intended for use by goroutines other than t's task
+// goroutine; for example, signal delivery to t will not interrupt goroutines
+// that are blocking using the returned context.Context.
+func (t *Task) AsyncContext() context.Context {
+	return taskAsyncContext{t: t}
+}
+
+// Debugf implements log.Logger.Debugf.
+func (ctx taskAsyncContext) Debugf(format string, v ...interface{}) {
+	ctx.t.Debugf(format, v...)
+}
+
+// Infof implements log.Logger.Infof.
+func (ctx taskAsyncContext) Infof(format string, v ...interface{}) {
+	ctx.t.Infof(format, v...)
+}
+
+// Warningf implements log.Logger.Warningf.
+func (ctx taskAsyncContext) Warningf(format string, v ...interface{}) {
+	ctx.t.Warningf(format, v...)
+}
+
+// IsLogging implements log.Logger.IsLogging.
+func (ctx taskAsyncContext) IsLogging(level log.Level) bool {
+	return ctx.t.IsLogging(level)
+}
+
+// Deadline implements context.Context.Deadline.
+func (ctx taskAsyncContext) Deadline() (time.Time, bool) {
+	return time.Time{}, false
+}
+
+// Done implements context.Context.Done.
+func (ctx taskAsyncContext) Done() <-chan struct{} {
+	return nil
+}
+
+// Err implements context.Context.Err.
+func (ctx taskAsyncContext) Err() error {
+	return nil
+}
+
+// Value implements context.Context.Value.
+func (ctx taskAsyncContext) Value(key interface{}) interface{} {
+	return ctx.t.contextValue(key, false /* isTaskGoroutine */)
+}