src/mutex.h

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