Send SIGPIPE for closed pipes.

Fixes #5974
Updates #161

PiperOrigin-RevId: 375024740

4 files changed, 49 insertions, 0 deletions

diff --git a/pkg/abi/linux/BUILD b/pkg/abi/linux/BUILD
index a461bb65e..29ead20d0 100644
--- a/pkg/abi/linux/BUILD
+++ b/pkg/abi/linux/BUILD
@@ -15,6 +15,7 @@ go_library(
         "bpf.go",
         "capability.go",
         "clone.go",
+        "context.go",
         "dev.go",
         "elf.go",
         "epoll.go",
@@ -77,6 +78,7 @@ go_library(
     deps = [
         "//pkg/abi",
         "//pkg/bits",
+        "//pkg/context",
         "//pkg/marshal",
         "//pkg/marshal/primitive",
     ],
diff --git a/pkg/abi/linux/context.go b/pkg/abi/linux/context.go
new file mode 100644
index 000000000..d2dbba183
--- /dev/null
+++ b/pkg/abi/linux/context.go
@@ -0,0 +1,36 @@
+// Copyright 2021 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 linux
+
+import (
+	"gvisor.dev/gvisor/pkg/context"
+)
+
+// contextID is the linux package's type for context.Context.Value keys.
+type contextID int
+
+const (
+	// CtxSignalNoInfoFunc is a Context.Value key for a function to send signals.
+	CtxSignalNoInfoFunc contextID = iota
+)
+
+// SignalNoInfoFuncFromContext returns a callback function that can be used to send a
+// signal to the given context.
+func SignalNoInfoFuncFromContext(ctx context.Context) func(Signal) error {
+	if f := ctx.Value(CtxSignalNoInfoFunc); f != nil {
+		return f.(func(Signal) error)
+	}
+	return nil
+}
diff --git a/pkg/sentry/kernel/pipe/pipe_util.go b/pkg/sentry/kernel/pipe/pipe_util.go
index 2d89b9ccd..24e467e93 100644
--- a/pkg/sentry/kernel/pipe/pipe_util.go
+++ b/pkg/sentry/kernel/pipe/pipe_util.go
@@ -86,6 +86,12 @@ func (p *Pipe) Write(ctx context.Context, src usermem.IOSequence) (int64, error)
 	if n > 0 {
 		p.Notify(waiter.ReadableEvents)
 	}
+	if err == unix.EPIPE {
+		// If we are returning EPIPE send SIGPIPE to the task.
+		if sendSig := linux.SignalNoInfoFuncFromContext(ctx); sendSig != nil {
+			sendSig(linux.SIGPIPE)
+		}
+	}
 	return n, err
 }
 
diff --git a/pkg/sentry/kernel/task_context.go b/pkg/sentry/kernel/task_context.go
index 70b0699dc..c82d9e82b 100644
--- a/pkg/sentry/kernel/task_context.go
+++ b/pkg/sentry/kernel/task_context.go
@@ -17,6 +17,7 @@ package kernel
 import (
 	"time"
 
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -113,6 +114,10 @@ func (t *Task) contextValue(key interface{}, isTaskGoroutine bool) interface{} {
 		return t.k.RealtimeClock()
 	case limits.CtxLimits:
 		return t.tg.limits
+	case linux.CtxSignalNoInfoFunc:
+		return func(sig linux.Signal) error {
+			return t.SendSignal(SignalInfoNoInfo(sig, t, t))
+		}
 	case pgalloc.CtxMemoryFile:
 		return t.k.mf
 	case pgalloc.CtxMemoryFileProvider: