mono/utils/mono-semaphore.c

   1 /*
   2  * mono-semaphore.c: mono-semaphore functions
   3  *
   4  * Author:
   5  *      Gonzalo Paniagua Javier  <gonzalo@novell.com>
   6  *
   7  * (C) 2010 Novell, Inc.
   8  */
   9
  10 #include <config.h>
  11 #include <errno.h>
  12 #include "utils/mono-semaphore.h"
  13 #ifdef HAVE_SYS_TIME_H
  14 #include <sys/time.h>
  15 #endif
  16 #ifdef HAVE_UNISTD_H
  17 #include <unistd.h>
  18 #endif
  19
  20 #if (defined(HAVE_SEMAPHORE_H) || defined(USE_MACH_SEMA))
  21 /* sem_* or semaphore_* functions in use */
  22 #  ifdef USE_MACH_SEMA
  23 #    define TIMESPEC mach_timespec_t
  24 #    define WAIT_BLOCK(a,b) semaphore_timedwait (*(a), *(b))
  25 #  elif defined(__OpenBSD__)
  26 #    define TIMESPEC struct timespec
  27 #    define WAIT_BLOCK(a) sem_trywait(a)
  28 #  else
  29 #    define TIMESPEC struct timespec
  30 #    define WAIT_BLOCK(a,b) sem_timedwait (a, b)
  31 #  endif
  32
  33 #define NSEC_PER_SEC 1000000000
  34 int
  35 mono_sem_timedwait (MonoSemType *sem, guint32 timeout_ms, gboolean alertable)
  36 {
  37         TIMESPEC ts, copy;
  38         struct timeval t;
  39         int res = 0;
  40 #if defined(__OpenBSD__)
  41         int timeout;
  42 #endif
  43
  44 #ifndef USE_MACH_SEMA
  45         if (timeout_ms == 0)
  46                 return (!sem_trywait (sem));
  47 #endif
  48         if (timeout_ms == (guint32) 0xFFFFFFFF)
  49                 return mono_sem_wait (sem, alertable);
  50
  51         gettimeofday (&t, NULL);
  52         ts.tv_sec = timeout_ms / 1000 + t.tv_sec;
  53         ts.tv_nsec = (timeout_ms % 1000) * 1000000 + t.tv_usec * 1000;
  54         while (ts.tv_nsec > NSEC_PER_SEC) {
  55                 ts.tv_nsec -= NSEC_PER_SEC;
  56                 ts.tv_sec++;
  57         }
  58 #if defined(__OpenBSD__)
  59         timeout = ts.tv_sec;
  60         while (timeout) {
  61                 if ((res = WAIT_BLOCK (sem)) == 0)
  62                         return res;
  63
  64                 if (alertable)
  65                         return -1;
  66
  67                 usleep (ts.tv_nsec / 1000);
  68                 timeout--;
  69         }
  70 #else
  71         copy = ts;
  72         while ((res = WAIT_BLOCK (sem, &ts) == -1) && errno == EINTR) {
  73                 struct timeval current;
  74                 if (alertable)
  75                         return -1;
  76                 gettimeofday (&current, NULL);
  77                 ts = copy;
  78                 ts.tv_sec -= (current.tv_sec - t.tv_sec);
  79                 ts.tv_nsec -= (current.tv_usec - t.tv_usec) * 1000;
  80                 if (ts.tv_nsec < 0) {
  81                         if (ts.tv_sec <= 0) {
  82                                 ts.tv_nsec = 0;
  83                         } else {
  84                                 ts.tv_sec--;
  85                                 ts.tv_nsec += NSEC_PER_SEC;
  86                         }
  87                 }
  88                 if (ts.tv_sec < 0) {
  89                         ts.tv_sec = 0;
  90                         ts.tv_nsec = 0;
  91                 }
  92         }
  93 #endif
  94         return res;
  95 }
  96
  97 int
  98 mono_sem_wait (MonoSemType *sem, gboolean alertable)
  99 {
 100         int res;
 101 #ifndef USE_MACH_SEMA
 102         while ((res = sem_wait (sem) == -1) && errno == EINTR)
 103 #else
 104         while ((res = semaphore_wait (*sem) == -1) && errno == EINTR)
 105 #endif
 106         {
 107                 if (alertable)
 108                         return -1;
 109         }
 110         return res;
 111 }
 112
 113 int
 114 mono_sem_post (MonoSemType *sem)
 115 {
 116         int res;
 117 #ifndef USE_MACH_SEMA
 118         while ((res = sem_post (sem) == -1) && errno == EINTR);
 119 #else
 120         while ((res = semaphore_signal (*sem) == -1) && errno == EINTR);
 121 #endif
 122         return res;
 123 }
 124
 125 #else
 126 /* Windows or io-layer functions in use */
 127 int
 128 mono_sem_wait (MonoSemType *sem, gboolean alertable)
 129 {
 130         return mono_sem_timedwait (sem, INFINITE, alertable);
 131 }
 132
 133 int
 134 mono_sem_timedwait (MonoSemType *sem, guint32 timeout_ms, gboolean alertable)
 135 {
 136         gboolean res;
 137
 138         res = WaitForSingleObjectEx (*sem, timeout_ms, alertable);
 139         switch (res) {
 140         case WAIT_OBJECT_0:
 141                 return 0;
 142         case WAIT_IO_COMPLETION:
 143                 errno = EINTR;
 144                 return -1;
 145         // WAIT_TIMEOUT and WAIT_FAILED
 146         default:
 147                 return -1;
 148         }
 149 }
 150
 151 int
 152 mono_sem_post (MonoSemType *sem)
 153 {
 154         if (!ReleaseSemaphore (*sem, 1, NULL))
 155                 return -1;
 156         return 0;
 157 }
 158 #endif
 159