runsc: Add --pid flag to runsc kill.

--pid allows specific processes to be signalled rather than the container root
process or all processes in the container. containerd needs to SIGKILL exec'd
processes that timeout and check whether processes are still alive.

PiperOrigin-RevId: 217547636
Change-Id: I2058ebb548b51c8eb748f5884fb88bad0b532e45

1 files changed, 15 insertions, 2 deletions

diff --git a/runsc/cmd/kill.go b/runsc/cmd/kill.go
index dcb2988e3..7a98d10a2 100644
--- a/runsc/cmd/kill.go
+++ b/runsc/cmd/kill.go
@@ -31,6 +31,7 @@ import (
 // Kill implements subcommands.Command for the "kill" command.
 type Kill struct {
 	all bool
+	pid int
 }
 
 // Name implements subcommands.Command.Name.
@@ -51,6 +52,7 @@ func (*Kill) Usage() string {
 // SetFlags implements subcommands.Command.SetFlags.
 func (k *Kill) SetFlags(f *flag.FlagSet) {
 	f.BoolVar(&k.all, "all", false, "send the specified signal to all processes inside the container")
+	f.IntVar(&k.pid, "pid", 0, "send the specified signal to a specific process")
 }
 
 // Execute implements subcommands.Command.Execute.
@@ -63,6 +65,10 @@ func (k *Kill) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
 	id := f.Arg(0)
 	conf := args[0].(*boot.Config)
 
+	if k.pid != 0 && k.all {
+		Fatalf("it is invalid to specify both --all and --pid")
+	}
+
 	c, err := container.Load(conf.RootDir, id)
 	if err != nil {
 		Fatalf("error loading container: %v", err)
@@ -80,8 +86,15 @@ func (k *Kill) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
 	if err != nil {
 		Fatalf("%v", err)
 	}
-	if err := c.Signal(sig, k.all); err != nil {
-		Fatalf("%v", err)
+
+	if k.pid != 0 {
+		if err := c.SignalProcess(sig, int32(k.pid)); err != nil {
+			Fatalf("failed to signal pid %d: %v", k.pid, err)
+		}
+	} else {
+		if err := c.SignalContainer(sig, k.all); err != nil {
+			Fatalf("%v", err)
+		}
 	}
 	return subcommands.ExitSuccess
 }