Forward SIGUSR2 to the sandbox too

SIGUSR2 was being masked out to be used as a way to dump sentry
stacks. This could cause compatibility problems in cases anyone
uses SIGUSR2 to communicate with the container init process.

PiperOrigin-RevId: 201575374
Change-Id: I312246e828f38ad059139bb45b8addc2ed055d74

1 files changed, 2 insertions, 8 deletions

diff --git a/pkg/sentry/sighandling/sighandling.go b/pkg/sentry/sighandling/sighandling.go
index 0c3a14da5..ef6f7f617 100644
--- a/pkg/sentry/sighandling/sighandling.go
+++ b/pkg/sentry/sighandling/sighandling.go
@@ -95,7 +95,7 @@ func forwardSignals(k *kernel.Kernel, sigchans []chan os.Signal, start, stop cha
 // PrepareForwarding ensures that synchronous signals are forwarded to k and
 // returns a callback that starts signal delivery, which itself returns a
 // callback that stops signal forwarding.
-func PrepareForwarding(k *kernel.Kernel) func() func() {
+func PrepareForwarding(k *kernel.Kernel, enablePanicSignal bool) func() func() {
 	start := make(chan struct{})
 	stop := make(chan struct{})
 
@@ -112,7 +112,7 @@ func PrepareForwarding(k *kernel.Kernel) func() func() {
 		sigchans = append(sigchans, sigchan)
 
 		// SignalPanic is handled by Run.
-		if linux.Signal(sig) == kernel.SignalPanic {
+		if enablePanicSignal && linux.Signal(sig) == kernel.SignalPanic {
 			continue
 		}
 
@@ -128,9 +128,3 @@ func PrepareForwarding(k *kernel.Kernel) func() func() {
 		}
 	}
 }
-
-// StartForwarding ensures that synchronous signals are forwarded to k and
-// returns a callback that stops signal forwarding.
-func StartForwarding(k *kernel.Kernel) func() {
-	return PrepareForwarding(k)()
-}