src/mutex.h

   1 /*
   2     Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015,
   3     2016
   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_SYS_TIME_H
  29 #include <sys/time.h>
  30 #endif
  31
  32 #ifdef HAVE_TIME_H
  33 #include <time.h>
  34 #endif
  35
  36 #ifdef HAVE_SYS_SELECT_H
  37 #include <sys/select.h>
  38 #else
  39 #include <sys/types.h>
  40 #include <unistd.h>
  41 #endif
  42
  43 #ifdef HAVE_SYS_FILE_H
  44 #include <sys/file.h>
  45 #endif
  46
  47 #ifdef HAVE_FCNTL_H
  48 #include <fcntl.h>
  49 #endif
  50
  51 #include <pthread.h>
  52 #include <assert.h>
  53 #include <errno.h>
  54 #include "rcfile.h"
  55
  56 #define INIT_TIMESPEC(t, ts) do {                       \
  57         long s = (t*100000000)/1000000000;              \
  58         long l = (t*100000000)%1000000000;              \
  59         clock_gettime(CLOCK_REALTIME, &ts);             \
  60         ts.tv_sec += s;                                 \
  61         if (ts.tv_nsec + l >= 1000000000) {             \
  62             ts.tv_sec++;                                \
  63             ts.tv_nsec = 0;                             \
  64         }                                               \
  65         else                                            \
  66             ts.tv_nsec += l;                            \
  67     } while (0)
  68
  69 #ifdef MUTEX_DEBUG
  70 #define MUTEX_LOCK_DEBUG(m) do { \
  71         log_write("%s(%i): %s(): LOCK %p", __FILE__, __LINE__, \
  72                   __FUNCTION__, m);                            \
  73     } while (0)
  74
  75 #define MUTEX_UNLOCK_DEBUG(m) do { \
  76         log_write("%s(%i): %s(): UNLOCK %p", __FILE__, __LINE__, \
  77                   __FUNCTION__, m);                              \
  78     } while (0)
  79 #else
  80 #define MUTEX_LOCK_DEBUG(m)
  81 #define MUTEX_UNLOCK_DEBUG(m)
  82 #endif
  83
  84 #define MUTEX_LOCK(m) do {                              \
  85         MUTEX_LOCK_DEBUG(m);                            \
  86         while (pthread_mutex_trylock (m) == EBUSY) {    \
  87             struct timeval tv = { 0, 3000 };            \
  88             TEST_CANCEL ();                             \
  89             select (0, NULL, NULL, NULL, &tv);          \
  90         };                                              \
  91     } while (0)
  92
  93 #define MUTEX_UNLOCK(m) do {                    \
  94         MUTEX_UNLOCK_DEBUG(m);                  \
  95         pthread_mutex_unlock(m);                \
  96     } while (0)
  97
  98 #define TIMED_LOCK_DURATION     100000
  99 #ifdef HAVE_FLOCK
 100 #define TRY_FLOCK(ctx, fd, type, rc) do {                       \
 101         long ka = (long)config_get_integer ("global", "keepalive_interval"); \
 102         int to = config_get_integer ("global", "lock_timeout"); \
 103         for (long elapsed = 0; ; elapsed++) {                   \
 104             struct timeval tv = { 0, TIMED_LOCK_DURATION };     \
 105             int n = flock (fd, type|LOCK_NB);                   \
 106             if (n == -1 && errno == EWOULDBLOCK)                \
 107               {                                                 \
 108                 if (to == -1 || elapsed >= to) {                \
 109                     rc = GPG_ERR_LOCKED;                        \
 110                     break;                                      \
 111                 }                                               \
 112                 select (0, NULL, NULL, NULL, &tv);              \
 113                 if (ctx && ka && elapsed && !((elapsed+1*10) % (ka*10))) { \
 114                   rc = send_status (ctx, STATUS_KEEPALIVE, NULL); \
 115                   if (rc)                                       \
 116                     break;                                      \
 117                 }                                               \
 118                 TEST_CANCEL();                                  \
 119               }                                                 \
 120             else if (n == -1)                                   \
 121               rc = gpg_error_from_errno (errno);                \
 122             else                                                \
 123               break;                                            \
 124         }                                                       \
 125 } while (0)
 126 #else
 127 #define TRY_FLOCK(ctx, fd, type, rc) do {                       \
 128     rc = 0;                                                     \
 129 } while (0)
 130 #endif
 131
 132 #define MUTEX_TIMED_LOCK(ctx, m, timeout, rc) do {              \
 133         long ka = (long)config_get_integer ("global", "keepalive_interval"); \
 134         for (long elapsed = 0; ; elapsed++) {                   \
 135             struct timeval tv = { 0, TIMED_LOCK_DURATION };     \
 136             if (pthread_mutex_trylock(m) == EBUSY) {            \
 137                 if (timeout == -1 || elapsed >= timeout) {      \
 138                     rc = GPG_ERR_LOCKED;                        \
 139                     break;                                      \
 140                 }                                               \
 141                 select (0, NULL, NULL, NULL, &tv);              \
 142                 if (ctx && ka && elapsed && !((elapsed+1*10) % (ka*10))) { \
 143                   rc = send_status (ctx, STATUS_KEEPALIVE, NULL); \
 144                   if (rc)                                       \
 145                     break;                                      \
 146                 }                                               \
 147                 TEST_CANCEL();                                  \
 148             }                                                   \
 149             else {                                              \
 150                 MUTEX_LOCK_DEBUG(m);                            \
 151                 break;                                          \
 152             }                                                   \
 153         }                                                       \
 154     } while (0)
 155
 156 #define MUTEX_TRYLOCK(ctx, m, rc, t) do {                       \
 157         int n;                                                  \
 158         rc = 0;                                                 \
 159         if ((n = pthread_mutex_trylock(m)) == EBUSY) {          \
 160             if (t != -1) {                                      \
 161                 if (ctx)                                        \
 162                   rc = send_status(ctx, STATUS_LOCKED, NULL);   \
 163                 if (!rc && t != 0) {                            \
 164                     MUTEX_TIMED_LOCK(ctx, m, t, rc);            \
 165                 }                                               \
 166                 else if (!rc) {                                 \
 167                     MUTEX_LOCK_DEBUG(m);                        \
 168                 }                                               \
 169             }                                                   \
 170             else                                                \
 171                 rc = GPG_ERR_LOCKED;                            \
 172         }                                                       \
 173         else if (n)                                             \
 174             rc = gpg_error_from_errno(n);                       \
 175         else                                                    \
 176             MUTEX_LOCK_DEBUG(m);                                \
 177     } while (0)
 178
 179 #endif