tools/syz-testbed: do not send SIGKILL to syz-managers

Doing so can result in syz-manager leaking GCE instances. Set PDEATHSIG
to SIGTERM instead, so that syz-manager has a change to exit gracefully.

7 files changed, 24 insertions, 10 deletions

diff --git a/pkg/osutil/osutil.go b/pkg/osutil/osutil.go
index 82c356978..ae8ebc2fb 100644
--- a/pkg/osutil/osutil.go
+++ b/pkg/osutil/osutil.go
@@ -38,7 +38,7 @@ func Run(timeout time.Duration, cmd *exec.Cmd) ([]byte, error) {
 	if cmd.Stderr == nil {
 		cmd.Stderr = output
 	}
-	setPdeathsig(cmd)
+	setPdeathsig(cmd, true)
 	if err := cmd.Start(); err != nil {
 		return nil, fmt.Errorf("failed to start %v %+v: %v", cmd.Path, cmd.Args, err)
 	}
@@ -78,10 +78,20 @@ func Run(timeout time.Duration, cmd *exec.Cmd) ([]byte, error) {
 	return output.Bytes(), nil
 }
 
-// Command is similar to os/exec.Command, but also sets PDEATHSIG on linux.
+// Command is similar to os/exec.Command, but also sets PDEATHSIG to SIGKILL on linux,
+// i.e. the child will be killed immediately.
 func Command(bin string, args ...string) *exec.Cmd {
 	cmd := exec.Command(bin, args...)
-	setPdeathsig(cmd)
+	setPdeathsig(cmd, true)
+	return cmd
+}
+
+// Command is similar to os/exec.Command, but also sets PDEATHSIG to SIGTERM on linux,
+// i.e. the child has a chance to exit gracefully. This may be important when running
+// e.g. syz-manager. If it is killed immediately, it can leak GCE instances.
+func GraciousCommand(bin string, args ...string) *exec.Cmd {
+	cmd := exec.Command(bin, args...)
+	setPdeathsig(cmd, false)
 	return cmd
 }
 
diff --git a/pkg/osutil/osutil_akaros.go b/pkg/osutil/osutil_akaros.go
index 210a208e8..1ef9f4538 100644
--- a/pkg/osutil/osutil_akaros.go
+++ b/pkg/osutil/osutil_akaros.go
@@ -33,7 +33,7 @@ func SandboxChown(file string) error {
 	return nil
 }
 
-func setPdeathsig(cmd *exec.Cmd) {
+func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 }
 
 func killPgroup(cmd *exec.Cmd) {
diff --git a/pkg/osutil/osutil_bsd.go b/pkg/osutil/osutil_bsd.go
index 221f86054..d139b9a76 100644
--- a/pkg/osutil/osutil_bsd.go
+++ b/pkg/osutil/osutil_bsd.go
@@ -30,7 +30,7 @@ func SandboxChown(file string) error {
 	return nil
 }
 
-func setPdeathsig(cmd *exec.Cmd) {
+func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 }
 
 func killPgroup(cmd *exec.Cmd) {
diff --git a/pkg/osutil/osutil_darwin.go b/pkg/osutil/osutil_darwin.go
index 016e692f7..22c667ed7 100644
--- a/pkg/osutil/osutil_darwin.go
+++ b/pkg/osutil/osutil_darwin.go
@@ -27,7 +27,7 @@ func SandboxChown(file string) error {
 	return nil
 }
 
-func setPdeathsig(cmd *exec.Cmd) {
+func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 }
 
 func killPgroup(cmd *exec.Cmd) {
diff --git a/pkg/osutil/osutil_fuchsia.go b/pkg/osutil/osutil_fuchsia.go
index da596d47a..f1dad3aff 100644
--- a/pkg/osutil/osutil_fuchsia.go
+++ b/pkg/osutil/osutil_fuchsia.go
@@ -47,7 +47,7 @@ func SandboxChown(file string) error {
 	return nil
 }
 
-func setPdeathsig(cmd *exec.Cmd) {
+func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 }
 
 func killPgroup(cmd *exec.Cmd) {
diff --git a/pkg/osutil/osutil_linux.go b/pkg/osutil/osutil_linux.go
index 768620d21..fb7a0670c 100644
--- a/pkg/osutil/osutil_linux.go
+++ b/pkg/osutil/osutil_linux.go
@@ -124,11 +124,15 @@ func usernameToID(what string) (uint32, error) {
 	return uint32(id), nil
 }
 
-func setPdeathsig(cmd *exec.Cmd) {
+func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 	if cmd.SysProcAttr == nil {
 		cmd.SysProcAttr = new(syscall.SysProcAttr)
 	}
-	cmd.SysProcAttr.Pdeathsig = syscall.SIGKILL
+	if hardKill {
+		cmd.SysProcAttr.Pdeathsig = syscall.SIGKILL
+	} else {
+		cmd.SysProcAttr.Pdeathsig = syscall.SIGTERM
+	}
 	// We will kill the whole process group.
 	cmd.SysProcAttr.Setpgid = true
 }
diff --git a/pkg/osutil/osutil_windows.go b/pkg/osutil/osutil_windows.go
index 21649a8c3..8a0e8b77a 100644
--- a/pkg/osutil/osutil_windows.go
+++ b/pkg/osutil/osutil_windows.go
@@ -44,7 +44,7 @@ func SandboxChown(file string) error {
 	return nil
 }
 
-func setPdeathsig(cmd *exec.Cmd) {
+func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 }
 
 func killPgroup(cmd *exec.Cmd) {