src/mutex.h

   1 /*
   2     Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
   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 #define INIT_TIMESPEC(t, ts) do {                       \
  36         long s = (t*100000000)/1000000000;              \
  37         long l = (t*100000000)%1000000000;              \
  38         clock_gettime(CLOCK_REALTIME, &ts);             \
  39         ts.tv_sec += s;                                 \
  40         if (ts.tv_nsec + l >= 1000000000) {             \
  41             ts.tv_sec++;                                \
  42             ts.tv_nsec = 0;                             \
  43         }                                               \
  44         else                                            \
  45             ts.tv_nsec += l;                            \
  46     } while (0)
  47
  48 #ifdef MUTEX_DEBUG
  49 #define MUTEX_LOCK_DEBUG(m) do { \
  50         log_write("%s(%i): %s(): LOCK %p", __FILE__, __LINE__, \
  51                   __FUNCTION__, m);                            \
  52     } while (0)
  53
  54 #define MUTEX_UNLOCK_DEBUG(m) do { \
  55         log_write("%s(%i): %s(): UNLOCK %p", __FILE__, __LINE__, \
  56                   __FUNCTION__, m);                              \
  57     } while (0)
  58 #else
  59 #define MUTEX_LOCK_DEBUG(m)
  60 #define MUTEX_UNLOCK_DEBUG(m)
  61 #endif
  62
  63 #define MUTEX_LOCK(m) do {                      \
  64         MUTEX_LOCK_DEBUG(m);                    \
  65         pthread_mutex_lock(m);                  \
  66     } while (0)
  67
  68 #define MUTEX_UNLOCK(m) do {                    \
  69         MUTEX_UNLOCK_DEBUG(m);                  \
  70         pthread_mutex_unlock(m);                \
  71     } while (0)
  72
  73 #ifdef HAVE_PTHREAD_MUTEX_TIMEDLOCK
  74 #define MUTEX_TIMED_LOCK(m, timeout, rc) do {                           \
  75         struct timespec ts;                                             \
  76         INIT_TIMESPEC(timeout, ts);                                     \
  77         int n = pthread_mutex_timedlock(m, &ts);                        \
  78         if (n == ETIMEDOUT) {                                           \
  79             rc = GPG_ERR_LOCKED;                                        \
  80         }                                                               \
  81         else if (!n) {                                                  \
  82             MUTEX_LOCK_DEBUG(m);                                        \
  83         }                                                               \
  84         else {                                                          \
  85             log_write("%s(%i): %s", __FILE__, __LINE__,                 \
  86                       pwmd_strerror(gpg_error_from_errno(n)));          \
  87             rc = gpg_error_from_errno(n);                               \
  88         }                                                               \
  89     } while (0)
  90 #else
  91 #define TIMED_LOCK_DURATION     100000
  92 #define MUTEX_TIMED_LOCK(m, timeout, rc) do {                   \
  93         for (long elapsed = 0; ; elapsed++) {                   \
  94             if (pthread_mutex_trylock(m) == EBUSY) {            \
  95                 if (timeout == -1 || elapsed >= timeout) {      \
  96                     rc = GPG_ERR_LOCKED;                        \
  97                     break;                                      \
  98                 }                                               \
  99                 usleep(TIMED_LOCK_DURATION);                    \
 100             }                                                   \
 101             else {                                              \
 102                 MUTEX_LOCK_DEBUG(m);                            \
 103                 break;                                          \
 104             }                                                   \
 105         }                                                       \
 106     } while (0)
 107 #endif
 108
 109 #define MUTEX_TRYLOCK(ctx, m, rc, t) do {                       \
 110         int n;                                                  \
 111         if ((n = pthread_mutex_trylock(m)) == EBUSY) {          \
 112             if (t != -1 && ctx) {                               \
 113                 rc = send_status(ctx, STATUS_LOCKED, NULL);     \
 114                 if (!rc && t != 0) {                            \
 115                     MUTEX_TIMED_LOCK(m, t, rc);                 \
 116                 }                                               \
 117                 else if (!rc) {                                 \
 118                     MUTEX_LOCK(m);                              \
 119                 }                                               \
 120             }                                                   \
 121             else                                                \
 122                 rc = GPG_ERR_LOCKED;                            \
 123         }                                                       \
 124         else if (n)                                             \
 125             rc = gpg_error_from_errno(n);                       \
 126         else                                                    \
 127             MUTEX_LOCK_DEBUG(m);                                \
 128     } while (0)
 129
 130 #endif