Implement command GETNCNT for semctl.

PiperOrigin-RevId: 341154192

2 files changed, 20 insertions, 7 deletions

diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go
index 650ca16e6..bb1f715e2 100644
--- a/pkg/sentry/syscalls/linux/linux64.go
+++ b/pkg/sentry/syscalls/linux/linux64.go
@@ -118,7 +118,7 @@ var AMD64 = &kernel.SyscallTable{
 		63:  syscalls.Supported("uname", Uname),
 		64:  syscalls.Supported("semget", Semget),
 		65:  syscalls.PartiallySupported("semop", Semop, "Option SEM_UNDO not supported.", nil),
-		66:  syscalls.PartiallySupported("semctl", Semctl, "Options IPC_INFO, SEM_INFO, SEM_STAT, SEM_STAT_ANY, GETNCNT not supported.", nil),
+		66:  syscalls.PartiallySupported("semctl", Semctl, "Options IPC_INFO, SEM_INFO, SEM_STAT, SEM_STAT_ANY not supported.", nil),
 		67:  syscalls.Supported("shmdt", Shmdt),
 		68:  syscalls.ErrorWithEvent("msgget", syserror.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921)
 		69:  syscalls.ErrorWithEvent("msgsnd", syserror.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921)
@@ -619,7 +619,7 @@ var ARM64 = &kernel.SyscallTable{
 		188: syscalls.ErrorWithEvent("msgrcv", syserror.ENOSYS, "", []string{"gvisor.dev/issue/135"}),          // TODO(b/29354921)
 		189: syscalls.ErrorWithEvent("msgsnd", syserror.ENOSYS, "", []string{"gvisor.dev/issue/135"}),          // TODO(b/29354921)
 		190: syscalls.Supported("semget", Semget),
-		191: syscalls.PartiallySupported("semctl", Semctl, "Options IPC_INFO, SEM_INFO, SEM_STAT, SEM_STAT_ANY, GETNCNT not supported.", nil),
+		191: syscalls.PartiallySupported("semctl", Semctl, "Options IPC_INFO, SEM_INFO, SEM_STAT, SEM_STAT_ANY not supported.", nil),
 		192: syscalls.ErrorWithEvent("semtimedop", syserror.ENOSYS, "", []string{"gvisor.dev/issue/137"}),
 		193: syscalls.PartiallySupported("semop", Semop, "Option SEM_UNDO not supported.", nil),
 		194: syscalls.PartiallySupported("shmget", Shmget, "Option SHM_HUGETLB is not supported.", nil),
diff --git a/pkg/sentry/syscalls/linux/sys_sem.go b/pkg/sentry/syscalls/linux/sys_sem.go
index 067f6be6d..e383a0a87 100644
--- a/pkg/sentry/syscalls/linux/sys_sem.go
+++ b/pkg/sentry/syscalls/linux/sys_sem.go
@@ -139,14 +139,17 @@ func Semctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
 		return 0, nil, err
 
 	case linux.GETZCNT:
-		v, err := getSemzcnt(t, id, num)
+		v, err := getZCnt(t, id, num)
+		return uintptr(v), nil, err
+
+	case linux.GETNCNT:
+		v, err := getNCnt(t, id, num)
 		return uintptr(v), nil, err
 
 	case linux.IPC_INFO,
 		linux.SEM_INFO,
 		linux.SEM_STAT,
-		linux.SEM_STAT_ANY,
-		linux.GETNCNT:
+		linux.SEM_STAT_ANY:
 
 		t.Kernel().EmitUnimplementedEvent(t)
 		fallthrough
@@ -262,12 +265,22 @@ func getPID(t *kernel.Task, id int32, num int32) (int32, error) {
 	return int32(tg.ID()), nil
 }
 
-func getSemzcnt(t *kernel.Task, id int32, num int32) (uint16, error) {
+func getZCnt(t *kernel.Task, id int32, num int32) (uint16, error) {
+	r := t.IPCNamespace().SemaphoreRegistry()
+	set := r.FindByID(id)
+	if set == nil {
+		return 0, syserror.EINVAL
+	}
+	creds := auth.CredentialsFromContext(t)
+	return set.CountZeroWaiters(num, creds)
+}
+
+func getNCnt(t *kernel.Task, id int32, num int32) (uint16, error) {
 	r := t.IPCNamespace().SemaphoreRegistry()
 	set := r.FindByID(id)
 	if set == nil {
 		return 0, syserror.EINVAL
 	}
 	creds := auth.CredentialsFromContext(t)
-	return set.GetZeroWaiters(num, creds)
+	return set.CountNegativeWaiters(num, creds)
 }