1                 : /*
       2                 :  * Copyright 2008 The Native Client Authors. All rights reserved.
       3                 :  * Use of this source code is governed by a BSD-style license that can
       4                 :  * be found in the LICENSE file.
       5                 :  */
       6                 : 
       7                 : /*
       8                 :  * NaCl semaphore implementation (Linux)
       9                 :  */
      10                 : 
      11                 : #include <errno.h>
      12                 : #include <unistd.h>
      13                 : 
      14                 : #include "native_client/src/shared/platform/linux/nacl_semaphore.h"
      15                 : #include "native_client/src/shared/platform/nacl_log.h"
      16                 : #include "native_client/src/shared/platform/nacl_sync.h"
      17                 : 
      18               1 : int NaClSemCtor(struct NaClSemaphore *sem, int32_t value) {
      19                 :   /*
      20                 :    * TODO(gregoryd): make sure that sem_init behaves identically on all
      21                 :    * platforms. Examples: negative values, very large value.
      22                 :    */
      23               1 :   return (0 == sem_init(&sem->sem_obj, 0, value));
      24                 : }
      25                 : 
      26               1 : void NaClSemDtor(struct NaClSemaphore *sem) {
      27               1 :   sem_destroy(&sem->sem_obj);
      28               1 : }
      29                 : 
      30              12 : NaClSyncStatus NaClSemWait(struct NaClSemaphore *sem) {
      31              12 :   sem_wait(&sem->sem_obj);  /* always returns 0 */
      32              12 :   return NACL_SYNC_OK;
      33                 : }
      34                 : 
      35              71 : NaClSyncStatus NaClSemTryWait(struct NaClSemaphore *sem) {
      36              71 :   if (0 == sem_trywait(&sem->sem_obj)) {
      37               4 :     return NACL_SYNC_OK;
      38                 :   }
      39              68 :   return NACL_SYNC_BUSY;
      40                 : }
      41                 : 
      42              16 : NaClSyncStatus NaClSemPost(struct NaClSemaphore *sem) {
      43              16 :   if (0 == sem_post(&sem->sem_obj)) {
      44              16 :     return NACL_SYNC_OK;
      45                 :   }
      46                 :   /* Posting above SEM_MAX_VALUE does not always fail, but sometimes it may */
      47               0 :   if ((ERANGE == errno) || (EOVERFLOW == errno)) {
      48               0 :     return NACL_SYNC_SEM_RANGE_ERROR;
      49                 :   }
      50               0 :   return NACL_SYNC_INTERNAL_ERROR;
      51                 : }
      52                 : 
      53               0 : int32_t NaClSemGetValue(struct NaClSemaphore *sem) {
      54                 :   int32_t value;
      55               0 :   sem_getvalue(&sem->sem_obj, &value);  /* always returns 0 */
      56               0 :   return value;
      57                 : }