Add context to state.

PiperOrigin-RevId: 277840416

1 files changed, 39 insertions, 24 deletions

diff --git a/pkg/sentry/context/context.go b/pkg/sentry/context/context.go
index dfd62cbdb..23e009ef3 100644
--- a/pkg/sentry/context/context.go
+++ b/pkg/sentry/context/context.go
@@ -12,10 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package context defines the sentry's Context type.
+// 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"
 )
@@ -59,6 +69,7 @@ func ThreadGroupIDFromContext(ctx Context) (tgid int32, ok bool) {
 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
@@ -72,19 +83,36 @@ type Context interface {
 	// 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
+}
 
-	// Value returns the value associated with this Context for key, or nil if
-	// no value is associated with key. Successive calls to Value with the same
-	// key returns the same result.
-	//
-	// A key identifies a specific value in a Context. Functions that wish to
-	// retrieve values from Context typically allocate a key in a global
-	// variable then use that key as the argument to Context.Value. A key can
-	// be any type that supports equality; packages should define keys as an
-	// unexported type to avoid collisions.
-	Value(key interface{}) interface{}
+// Err returns nil.
+func (NoopSleeper) Err() error {
+	return nil
 }
 
+// logContext implements basic logging.
 type logContext struct {
 	log.Logger
 	NoopSleeper
@@ -95,19 +123,6 @@ func (logContext) Value(key interface{}) interface{} {
 	return nil
 }
 
-// NoopSleeper is a noop implementation of amutex.Sleeper and
-// Context.UninterruptibleSleep* methods for anonymous embedding in other types
-// that do not want to notify kernel.Task about sleeps.
-type NoopSleeper struct {
-	amutex.NoopSleeper
-}
-
-// UninterruptibleSleepStart does nothing.
-func (NoopSleeper) UninterruptibleSleepStart(bool) {}
-
-// UninterruptibleSleepFinish does nothing.
-func (NoopSleeper) UninterruptibleSleepFinish(bool) {}
-
 // bgContext is the context returned by context.Background.
 var bgContext = &logContext{Logger: log.Log()}