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-rw-r--r--pkg/sentry/kernel/semaphore/semaphore.go23
-rw-r--r--pkg/sentry/syscalls/linux/linux64.go4
-rw-r--r--pkg/sentry/syscalls/linux/sys_sem.go17
3 files changed, 40 insertions, 4 deletions
diff --git a/pkg/sentry/kernel/semaphore/semaphore.go b/pkg/sentry/kernel/semaphore/semaphore.go
index c39ecfb8f..310762936 100644
--- a/pkg/sentry/kernel/semaphore/semaphore.go
+++ b/pkg/sentry/kernel/semaphore/semaphore.go
@@ -423,6 +423,29 @@ func (s *Set) GetPID(num int32, creds *auth.Credentials) (int32, error) {
return sem.pid, nil
}
+// GetZeroWaiters returns number of waiters waiting for the sem to go to zero.
+func (s *Set) GetZeroWaiters(num int32, creds *auth.Credentials) (uint16, error) {
+ s.mu.Lock()
+ defer s.mu.Unlock()
+
+ // The calling process must have read permission on the semaphore set.
+ if !s.checkPerms(creds, fs.PermMask{Read: true}) {
+ return 0, syserror.EACCES
+ }
+
+ sem := s.findSem(num)
+ if sem == nil {
+ return 0, syserror.ERANGE
+ }
+ var semzcnt uint16
+ for w := sem.waiters.Front(); w != nil; w = w.Next() {
+ if w.value == 0 {
+ semzcnt++
+ }
+ }
+ return semzcnt, nil
+}
+
// ExecuteOps attempts to execute a list of operations to the set. It only
// succeeds when all operations can be applied. No changes are made if it fails.
//
diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go
index 36902d177..650ca16e6 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, GETZCNT not supported.", nil),
+ 66: syscalls.PartiallySupported("semctl", Semctl, "Options IPC_INFO, SEM_INFO, SEM_STAT, SEM_STAT_ANY, GETNCNT 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, GETZCNT not supported.", nil),
+ 191: syscalls.PartiallySupported("semctl", Semctl, "Options IPC_INFO, SEM_INFO, SEM_STAT, SEM_STAT_ANY, GETNCNT 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 c2d4bf805..067f6be6d 100644
--- a/pkg/sentry/syscalls/linux/sys_sem.go
+++ b/pkg/sentry/syscalls/linux/sys_sem.go
@@ -138,12 +138,15 @@ func Semctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
return 0, nil, err
+ case linux.GETZCNT:
+ v, err := getSemzcnt(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.GETZCNT:
+ linux.GETNCNT:
t.Kernel().EmitUnimplementedEvent(t)
fallthrough
@@ -258,3 +261,13 @@ 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) {
+ r := t.IPCNamespace().SemaphoreRegistry()
+ set := r.FindByID(id)
+ if set == nil {
+ return 0, syserror.EINVAL
+ }
+ creds := auth.CredentialsFromContext(t)
+ return set.GetZeroWaiters(num, creds)
+}