diff options
| -rw-r--r-- | pkg/sentry/kernel/semaphore/semaphore.go | 35 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/linux64.go | 4 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_sem.go | 23 |
3 files changed, 48 insertions, 14 deletions
diff --git a/pkg/sentry/kernel/semaphore/semaphore.go b/pkg/sentry/kernel/semaphore/semaphore.go index 310762936..b99c0bffa 100644 --- a/pkg/sentry/kernel/semaphore/semaphore.go +++ b/pkg/sentry/kernel/semaphore/semaphore.go @@ -103,6 +103,7 @@ type waiter struct { waiterEntry // value represents how much resource the waiter needs to wake up. + // The value is either 0 or negative. value int16 ch chan struct{} } @@ -423,8 +424,7 @@ 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) { +func (s *Set) countWaiters(num int32, creds *auth.Credentials, pred func(w *waiter) bool) (uint16, error) { s.mu.Lock() defer s.mu.Unlock() @@ -437,13 +437,27 @@ func (s *Set) GetZeroWaiters(num int32, creds *auth.Credentials) (uint16, error) if sem == nil { return 0, syserror.ERANGE } - var semzcnt uint16 + var cnt uint16 for w := sem.waiters.Front(); w != nil; w = w.Next() { - if w.value == 0 { - semzcnt++ + if pred(w) { + cnt++ } } - return semzcnt, nil + return cnt, nil +} + +// CountZeroWaiters returns number of waiters waiting for the sem's value to increase. +func (s *Set) CountZeroWaiters(num int32, creds *auth.Credentials) (uint16, error) { + return s.countWaiters(num, creds, func(w *waiter) bool { + return w.value == 0 + }) +} + +// CountNegativeWaiters returns number of waiters waiting for the sem to go to zero. +func (s *Set) CountNegativeWaiters(num int32, creds *auth.Credentials) (uint16, error) { + return s.countWaiters(num, creds, func(w *waiter) bool { + return w.value < 0 + }) } // ExecuteOps attempts to execute a list of operations to the set. It only @@ -598,11 +612,18 @@ func (s *Set) destroy() { } } +func abs(val int16) int16 { + if val < 0 { + return -val + } + return val +} + // wakeWaiters goes over all waiters and checks which of them can be notified. func (s *sem) wakeWaiters() { // Note that this will release all waiters waiting for 0 too. for w := s.waiters.Front(); w != nil; { - if s.value < w.value { + if s.value < abs(w.value) { // Still blocked, skip it. w = w.Next() continue 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) } |