src/mutex.h

   1 /* vim:tw=78:ts=8:sw=4:set ft=c:  */
   2 /*
   3     Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012
   4     Ben Kibbey <bjk@luxsci.net>
   5
   6     This file is part of pwmd.
   7
   8     Pwmd is free software: you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation, either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     Pwmd is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with Pwmd.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21 #ifndef MUTEX_H
  22 #define MUTEX_H
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #ifdef HAVE_PTHREAD_MUTEX_TIMEDLOCK
  29 #include <time.h>
  30 #endif
  31
  32 #include <pthread.h>
  33 #include <assert.h>
  34 #include <errno.h>
  35
  36 #ifdef MUTEX_DEBUG
  37 #define MUTEX_LOCK_DEBUG(m) do { \
  38     log_write("%s(%i): %s(): LOCK %p", __FILE__, __LINE__, __FUNCTION__, m);
  39 } while (0)
  40 #define MUTEX_UNLOCK_DEBUG(m) do { \
  41     log_write("%s(%i): %s(): UNLOCK %p", __FILE__, __LINE__, __FUNCTION__, m);
  42 } while (0)
  43 #else
  44 #define MUTEX_LOCK_DEBUG(m)
  45 #define MUTEX_UNLOCK_DEBUG(m)
  46 #endif
  47
  48 #define MUTEX_LOCK(m) do { \
  49     MUTEX_LOCK_DEBUG(m); \
  50     pthread_mutex_lock(m); \
  51 } while (0)
  52
  53 #define MUTEX_UNLOCK(m) do { \
  54     MUTEX_UNLOCK_DEBUG(m); \
  55     pthread_mutex_unlock(m); \
  56 } while (0)
  57
  58 #ifdef HAVE_PTHREAD_MUTEX_TIMEDLOCK
  59 #define MUTEX_TIMED_LOCK(m, timeout, rc) do { \
  60     struct timespec ts; \
  61     clock_gettime(CLOCK_REALTIME, &ts); \
  62     time_t s = (timeout*100000000)/1000000000;\
  63     long l = (timeout*100000000)%1000000000; \
  64     ts.tv_sec += s; \
  65     ts.tv_nsec += l; \
  66     if (ts.tv_nsec >= 1000000000) {\
  67         ts.tv_sec++; \
  68         ts.tv_nsec -= 1000000000; \
  69     } \
  70     gint n = pthread_mutex_timedlock(m, &ts); \
  71     if (n == ETIMEDOUT) { \
  72         rc = GPG_ERR_LOCKED;\
  73     } \
  74     else if (!n) { \
  75         MUTEX_LOCK_DEBUG(m); \
  76     } \
  77     else { \
  78         log_write("%s(%i): %s", __FILE__, __LINE__, pwmd_strerror(gpg_error_from_errno(n))); \
  79         rc = gpg_error_from_errno(n);\
  80     } \
  81 } while (0)
  82 #else
  83 #define TIMED_LOCK_DURATION     100000
  84 #define MUTEX_TIMED_LOCK(m, timeout, rc) do { \
  85     for (glong elapsed = 0; ; elapsed++) { \
  86         if (pthread_mutex_trylock(m) == EBUSY) { \
  87             if (timeout == -1 || elapsed >= timeout) { \
  88                 rc = GPG_ERR_LOCKED; \
  89                 break; \
  90             } \
  91             usleep(TIMED_LOCK_DURATION); \
  92         } \
  93         else { \
  94             MUTEX_LOCK_DEBUG(m); \
  95             break;\
  96         } \
  97     } \
  98 } while (0)
  99 #endif
 100
 101 #define MUTEX_TRYLOCK(ctx, m, rc, t) do { \
 102     gint n; \
 103     if ((n = pthread_mutex_trylock(m)) == EBUSY) { \
 104         if (t != -1 && ctx) { \
 105             rc = send_status(ctx, STATUS_LOCKED, NULL); \
 106             if (!rc && t != 0) { \
 107                 MUTEX_TIMED_LOCK(m, t, rc); \
 108             } \
 109             else if (!rc) { \
 110                 MUTEX_LOCK(m); \
 111             } \
 112         } \
 113         else \
 114             rc = GPG_ERR_LOCKED; \
 115     } \
 116     else if (n) \
 117         rc = gpg_error_from_errno(n);\
 118     else \
 119         MUTEX_LOCK_DEBUG(m); \
 120 } while (0)
 121
 122 #endif