src/mutex.h

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