diff options
| -rw-r--r-- | libpod/lock/locks_test.go | 27 | ||||
| -rw-r--r-- | libpod/lock/shm_lock.c | 18 |
2 files changed, 43 insertions, 2 deletions
diff --git a/libpod/lock/locks_test.go b/libpod/lock/locks_test.go index b14d6e19a..ce4882643 100644 --- a/libpod/lock/locks_test.go +++ b/libpod/lock/locks_test.go @@ -3,6 +3,7 @@ package lock import ( "fmt" "os" + "syscall" "testing" "github.com/stretchr/testify/assert" @@ -46,6 +47,19 @@ func runLockTest(t *testing.T, testFunc func(*testing.T, *SHMLocks)) { t.Fatalf("Error opening locks: %v", err) } defer func() { + // Unlock and deallocate all locks + // Ignore EBUSY (lock is already unlocked) + // Ignore ENOENT (lock is not allocated) + var i uint32 + for i = 0; i < numLocks; i++ { + if err := locks.UnlockSemaphore(i); err != nil && err != syscall.EBUSY { + t.Fatalf("Error unlocking semaphore %d: %v", i, err) + } + if err := locks.DeallocateSemaphore(i); err != nil && err != syscall.ENOENT { + t.Fatalf("Error deallocating semaphore %d: %v", i, err) + } + } + if err := locks.Close(); err != nil { t.Fatalf("Error closing locks: %v", err) } @@ -82,3 +96,16 @@ func TestLockLifecycleSingleLock(t *testing.T) { assert.NoError(t, err) }) } + +// Test allocate two locks returns different locks +func TestAllocateTwoLocksGetsDifferentLocks(t *testing.T) { + runLockTest(t, func(t *testing.T, locks *SHMLocks) { + sem1, err := locks.AllocateSemaphore() + assert.NoError(t, err) + + sem2, err := locks.AllocateSemaphore() + assert.NoError(t, err) + + assert.NotEqual(t, sem1, sem2) + }) +} diff --git a/libpod/lock/shm_lock.c b/libpod/lock/shm_lock.c index ab715891c..48fd4d4a9 100644 --- a/libpod/lock/shm_lock.c +++ b/libpod/lock/shm_lock.c @@ -321,7 +321,8 @@ int32_t lock_semaphore(shm_struct_t *shm, uint32_t sem_index) { // subsequently realize they have been removed). // Returns 0 on success, -1 on failure int32_t unlock_semaphore(shm_struct_t *shm, uint32_t sem_index) { - int bitmap_index, index_in_bitmap; + int bitmap_index, index_in_bitmap, ret_code; + unsigned int sem_value = 0; if (shm == NULL) { return -1 * EINVAL; @@ -334,7 +335,20 @@ int32_t unlock_semaphore(shm_struct_t *shm, uint32_t sem_index) { bitmap_index = sem_index / BITMAP_SIZE; index_in_bitmap = sem_index % BITMAP_SIZE; - sem_post(&(shm->locks[bitmap_index].locks[index_in_bitmap])); + // Only allow a post if the semaphore is less than 1 (locked) + // This allows us to preserve mutex behavior + ret_code = sem_getvalue(&(shm->locks[bitmap_index].locks[index_in_bitmap]), &sem_value); + if (ret_code != 0) { + return -1 * errno; + } + if (sem_value >= 1) { + return -1 * EBUSY; + } + + ret_code = sem_post(&(shm->locks[bitmap_index].locks[index_in_bitmap])); + if (ret_code != 0) { + return -1 * errno; + } return 0; } |