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 #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__, __FUNCTION__, m);
  51 } while (0)
  52 #define MUTEX_UNLOCK_DEBUG(m) do { \
  53     log_write("%s(%i): %s(): UNLOCK %p", __FILE__, __LINE__, __FUNCTION__, m);
  54 } while (0)
  55 #else
  56 #define MUTEX_LOCK_DEBUG(m)
  57 #define MUTEX_UNLOCK_DEBUG(m)
  58 #endif
  59
  60 #define MUTEX_LOCK(m) do { \
  61     MUTEX_LOCK_DEBUG(m); \
  62     pthread_mutex_lock(m); \
  63 } while (0)
  64
  65 #define MUTEX_UNLOCK(m) do { \
  66     MUTEX_UNLOCK_DEBUG(m); \
  67     pthread_mutex_unlock(m); \
  68 } while (0)
  69
  70 #ifdef HAVE_PTHREAD_MUTEX_TIMEDLOCK
  71 #define MUTEX_TIMED_LOCK(m, timeout, rc) do { \
  72     struct timespec ts; \
  73     INIT_TIMESPEC(timeout, ts);                 \
  74     int n = pthread_mutex_timedlock(m, &ts); \
  75     if (n == ETIMEDOUT) { \
  76         rc = GPG_ERR_LOCKED;\
  77     } \
  78     else if (!n) { \
  79         MUTEX_LOCK_DEBUG(m); \
  80     } \
  81     else { \
  82         log_write("%s(%i): %s", __FILE__, __LINE__, pwmd_strerror(gpg_error_from_errno(n))); \
  83         rc = gpg_error_from_errno(n);\
  84     } \
  85 } while (0)
  86 #else
  87 #define TIMED_LOCK_DURATION     100000
  88 #define MUTEX_TIMED_LOCK(m, timeout, rc) do { \
  89     for (long elapsed = 0; ; elapsed++) { \
  90         if (pthread_mutex_trylock(m) == EBUSY) { \
  91             if (timeout == -1 || elapsed >= timeout) { \
  92                 rc = GPG_ERR_LOCKED; \
  93                 break; \
  94             } \
  95             usleep(TIMED_LOCK_DURATION); \
  96         } \
  97         else { \
  98             MUTEX_LOCK_DEBUG(m); \
  99             break;\
 100         } \
 101     } \
 102 } while (0)
 103 #endif
 104
 105 #define MUTEX_TRYLOCK(ctx, m, rc, t) do { \
 106     int n; \
 107     if ((n = pthread_mutex_trylock(m)) == EBUSY) { \
 108         if (t != -1 && ctx) { \
 109             rc = send_status(ctx, STATUS_LOCKED, NULL); \
 110             if (!rc && t != 0) { \
 111                 MUTEX_TIMED_LOCK(m, t, rc); \
 112             } \
 113             else if (!rc) { \
 114                 MUTEX_LOCK(m); \
 115             } \
 116         } \
 117         else \
 118             rc = GPG_ERR_LOCKED; \
 119     } \
 120     else if (n) \
 121         rc = gpg_error_from_errno(n);\
 122     else \
 123         MUTEX_LOCK_DEBUG(m); \
 124 } while (0)
 125
 126 #endif