Add WCLONE / WALL support to waitid

The previous commit adds WNOTHREAD support to waitid, so we may as well
complete the upstream change.

Linux added WCLONE, WALL, WNOTHREAD support to waitid(2) in
91c4e8ea8f05916df0c8a6f383508ac7c9e10dba ("wait: allow sys_waitid() to
accept __WNOTHREAD/__WCLONE/__WALL"). i.e., Linux 4.7.

PiperOrigin-RevId: 249560587
Change-Id: Iff177b0848a3f7bae6cb5592e44500c5a942fbeb

1 files changed, 35 insertions, 32 deletions

diff --git a/pkg/sentry/syscalls/linux/sys_thread.go b/pkg/sentry/syscalls/linux/sys_thread.go
index 14fa7ef92..26f7e8ead 100644
--- a/pkg/sentry/syscalls/linux/sys_thread.go
+++ b/pkg/sentry/syscalls/linux/sys_thread.go
@@ -181,6 +181,32 @@ func Vfork(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
 	return clone(t, syscall.CLONE_VM|syscall.CLONE_VFORK|int(syscall.SIGCHLD), 0, 0, 0, 0)
 }
 
+// parseCommonWaitOptions applies the options common to wait4 and waitid to
+// wopts.
+func parseCommonWaitOptions(wopts *kernel.WaitOptions, options int) error {
+	switch options & (linux.WCLONE | linux.WALL) {
+	case 0:
+		wopts.NonCloneTasks = true
+	case linux.WCLONE:
+		wopts.CloneTasks = true
+	case linux.WALL:
+		wopts.NonCloneTasks = true
+		wopts.CloneTasks = true
+	default:
+		return syscall.EINVAL
+	}
+	if options&linux.WCONTINUED != 0 {
+		wopts.Events |= kernel.EventGroupContinue
+	}
+	if options&linux.WNOHANG == 0 {
+		wopts.BlockInterruptErr = kernel.ERESTARTSYS
+	}
+	if options&linux.WNOTHREAD == 0 {
+		wopts.SiblingChildren = true
+	}
+	return nil
+}
+
 // wait4 waits for the given child process to exit.
 func wait4(t *kernel.Task, pid int, statusAddr usermem.Addr, options int, rusageAddr usermem.Addr) (uintptr, error) {
 	if options&^(linux.WNOHANG|linux.WUNTRACED|linux.WCONTINUED|linux.WNOTHREAD|linux.WALL|linux.WCLONE) != 0 {
@@ -207,29 +233,12 @@ func wait4(t *kernel.Task, pid int, statusAddr usermem.Addr, options int, rusage
 		wopts.SpecificTID = kernel.ThreadID(pid)
 	}
 
-	switch options & (linux.WCLONE | linux.WALL) {
-	case 0:
-		wopts.NonCloneTasks = true
-	case linux.WCLONE:
-		wopts.CloneTasks = true
-	case linux.WALL:
-		wopts.NonCloneTasks = true
-		wopts.CloneTasks = true
-	default:
-		return 0, syscall.EINVAL
+	if err := parseCommonWaitOptions(&wopts, options); err != nil {
+		return 0, err
 	}
 	if options&linux.WUNTRACED != 0 {
 		wopts.Events |= kernel.EventChildGroupStop
 	}
-	if options&linux.WCONTINUED != 0 {
-		wopts.Events |= kernel.EventGroupContinue
-	}
-	if options&linux.WNOHANG == 0 {
-		wopts.BlockInterruptErr = kernel.ERESTARTSYS
-	}
-	if options&linux.WNOTHREAD == 0 {
-		wopts.SiblingChildren = true
-	}
 
 	wr, err := t.Wait(&wopts)
 	if err != nil {
@@ -281,16 +290,15 @@ func Waitid(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
 	options := int(args[3].Uint())
 	rusageAddr := args[4].Pointer()
 
-	if options&^(linux.WNOHANG|linux.WEXITED|linux.WSTOPPED|linux.WCONTINUED|linux.WNOWAIT|linux.WNOTHREAD) != 0 {
+	if options&^(linux.WNOHANG|linux.WEXITED|linux.WSTOPPED|linux.WCONTINUED|linux.WNOWAIT|linux.WNOTHREAD|linux.WALL|linux.WCLONE) != 0 {
 		return 0, nil, syscall.EINVAL
 	}
 	if options&(linux.WEXITED|linux.WSTOPPED|linux.WCONTINUED) == 0 {
 		return 0, nil, syscall.EINVAL
 	}
 	wopts := kernel.WaitOptions{
-		NonCloneTasks: true,
-		Events:        kernel.EventTraceeStop,
-		ConsumeEvent:  options&linux.WNOWAIT == 0,
+		Events:       kernel.EventTraceeStop,
+		ConsumeEvent: options&linux.WNOWAIT == 0,
 	}
 	switch idtype {
 	case linux.P_ALL:
@@ -301,21 +309,16 @@ func Waitid(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
 	default:
 		return 0, nil, syscall.EINVAL
 	}
+
+	if err := parseCommonWaitOptions(&wopts, options); err != nil {
+		return 0, nil, err
+	}
 	if options&linux.WEXITED != 0 {
 		wopts.Events |= kernel.EventExit
 	}
 	if options&linux.WSTOPPED != 0 {
 		wopts.Events |= kernel.EventChildGroupStop
 	}
-	if options&linux.WCONTINUED != 0 {
-		wopts.Events |= kernel.EventGroupContinue
-	}
-	if options&linux.WNOHANG == 0 {
-		wopts.BlockInterruptErr = kernel.ERESTARTSYS
-	}
-	if options&linux.WNOTHREAD == 0 {
-		wopts.SiblingChildren = true
-	}
 
 	wr, err := t.Wait(&wopts)
 	if err != nil {