2019-04-29 21:25:05 +00:00
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// Copyright 2018 The gVisor Authors.
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2018-04-27 17:37:02 +00:00
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package kernel
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import (
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2019-11-01 01:02:04 +00:00
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"time"
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2019-06-13 23:49:09 +00:00
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"gvisor.dev/gvisor/pkg/log"
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"gvisor.dev/gvisor/pkg/sentry/context"
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2018-04-27 17:37:02 +00:00
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)
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// contextID is the kernel package's type for context.Context.Value keys.
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type contextID int
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const (
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// CtxCanTrace is a Context.Value key for a function with the same
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// signature and semantics as kernel.Task.CanTrace.
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CtxCanTrace contextID = iota
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// CtxKernel is a Context.Value key for a Kernel.
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CtxKernel
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// CtxPIDNamespace is a Context.Value key for a PIDNamespace.
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CtxPIDNamespace
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// CtxTask is a Context.Value key for a Task.
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CtxTask
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// CtxUTSNamespace is a Context.Value key for a UTSNamespace.
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CtxUTSNamespace
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// CtxIPCNamespace is a Context.Value key for a IPCNamespace.
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CtxIPCNamespace
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)
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// ContextCanTrace returns true if ctx is permitted to trace t, in the same sense
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// as kernel.Task.CanTrace.
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func ContextCanTrace(ctx context.Context, t *Task, attach bool) bool {
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if v := ctx.Value(CtxCanTrace); v != nil {
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return v.(func(*Task, bool) bool)(t, attach)
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}
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return false
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}
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// KernelFromContext returns the Kernel in which ctx is executing, or nil if
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// there is no such Kernel.
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func KernelFromContext(ctx context.Context) *Kernel {
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if v := ctx.Value(CtxKernel); v != nil {
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return v.(*Kernel)
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}
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return nil
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}
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// PIDNamespaceFromContext returns the PID namespace in which ctx is executing,
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// or nil if there is no such PID namespace.
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func PIDNamespaceFromContext(ctx context.Context) *PIDNamespace {
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if v := ctx.Value(CtxPIDNamespace); v != nil {
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return v.(*PIDNamespace)
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}
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return nil
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}
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// UTSNamespaceFromContext returns the UTS namespace in which ctx is executing,
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// or nil if there is no such UTS namespace.
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func UTSNamespaceFromContext(ctx context.Context) *UTSNamespace {
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if v := ctx.Value(CtxUTSNamespace); v != nil {
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return v.(*UTSNamespace)
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}
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return nil
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}
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// IPCNamespaceFromContext returns the IPC namespace in which ctx is executing,
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// or nil if there is no such IPC namespace.
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func IPCNamespaceFromContext(ctx context.Context) *IPCNamespace {
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if v := ctx.Value(CtxIPCNamespace); v != nil {
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return v.(*IPCNamespace)
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}
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return nil
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}
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// TaskFromContext returns the Task associated with ctx, or nil if there is no
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// such Task.
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func TaskFromContext(ctx context.Context) *Task {
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if v := ctx.Value(CtxTask); v != nil {
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return v.(*Task)
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}
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return nil
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}
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2019-11-01 01:02:04 +00:00
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// Deadline implements context.Context.Deadline.
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func (*Task) Deadline() (time.Time, bool) {
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return time.Time{}, false
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}
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// Done implements context.Context.Done.
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func (*Task) Done() <-chan struct{} {
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return nil
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}
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// Err implements context.Context.Err.
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func (*Task) Err() error {
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return nil
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}
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2018-04-27 17:37:02 +00:00
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// AsyncContext returns a context.Context that may be used by goroutines that
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// do work on behalf of t and therefore share its contextual values, but are
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// not t's task goroutine (e.g. asynchronous I/O).
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func (t *Task) AsyncContext() context.Context {
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return taskAsyncContext{t: t}
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}
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type taskAsyncContext struct {
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context.NoopSleeper
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t *Task
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}
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// Debugf implements log.Logger.Debugf.
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func (ctx taskAsyncContext) Debugf(format string, v ...interface{}) {
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ctx.t.Debugf(format, v...)
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}
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// Infof implements log.Logger.Infof.
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func (ctx taskAsyncContext) Infof(format string, v ...interface{}) {
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ctx.t.Infof(format, v...)
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}
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// Warningf implements log.Logger.Warningf.
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func (ctx taskAsyncContext) Warningf(format string, v ...interface{}) {
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ctx.t.Warningf(format, v...)
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}
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// IsLogging implements log.Logger.IsLogging.
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func (ctx taskAsyncContext) IsLogging(level log.Level) bool {
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return ctx.t.IsLogging(level)
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}
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2019-11-01 01:02:04 +00:00
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// Deadline implements context.Context.Deadline.
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func (ctx taskAsyncContext) Deadline() (time.Time, bool) {
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return ctx.t.Deadline()
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}
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// Done implements context.Context.Done.
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func (ctx taskAsyncContext) Done() <-chan struct{} {
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return ctx.t.Done()
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}
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// Err implements context.Context.Err.
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func (ctx taskAsyncContext) Err() error {
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return ctx.t.Err()
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}
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2018-04-27 17:37:02 +00:00
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// Value implements context.Context.Value.
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func (ctx taskAsyncContext) Value(key interface{}) interface{} {
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return ctx.t.Value(key)
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}
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