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         pthread_mutex_lock(m);                  \
  87     } while (0)
  88
  89 #define MUTEX_UNLOCK(m) do {                    \
  90         MUTEX_UNLOCK_DEBUG(m);                  \
  91         pthread_mutex_unlock(m);                \
  92     } while (0)
  93
  94 #define TIMED_LOCK_DURATION     100000
  95 #ifdef HAVE_FLOCK
  96 #define TRY_FLOCK(ctx, fd, type, rc) do {                       \
  97         long ka = (long)config_get_integer ("global", "keepalive_interval"); \
  98         int to = config_get_integer ("global", "lock_timeout"); \
  99         for (long elapsed = 0; ; elapsed++) {                   \
 100             struct timeval tv = { 0, TIMED_LOCK_DURATION };     \
 101             int n = flock (fd, type|LOCK_NB);                   \
 102             if (n == -1 && errno == EWOULDBLOCK)                \
 103               {                                                 \
 104                 if (to == -1 || elapsed >= to) {                \
 105                     rc = GPG_ERR_LOCKED;                        \
 106                     break;                                      \
 107                 }                                               \
 108                 select (0, NULL, NULL, NULL, &tv);              \
 109                 if (ctx && ka && elapsed && !((elapsed+1*10) % (ka*10))) { \
 110                   rc = send_status (ctx, STATUS_KEEPALIVE, NULL); \
 111                   if (rc)                                       \
 112                     break;                                      \
 113                 }                                               \
 114               }                                                 \
 115             else if (n == -1)                                   \
 116               rc = gpg_error_from_errno (errno);                \
 117             else                                                \
 118               break;                                            \
 119         }                                                       \
 120 } while (0)
 121 #else
 122 #define TRY_FLOCK(ctx, fd, type, rc) do {                       \
 123     rc = 0;                                                     \
 124 } while (0)
 125 #endif
 126
 127 #define MUTEX_TIMED_LOCK(ctx, m, timeout, rc) do {              \
 128         long ka = (long)config_get_integer ("global", "keepalive_interval"); \
 129         for (long elapsed = 0; ; elapsed++) {                   \
 130             struct timeval tv = { 0, TIMED_LOCK_DURATION };     \
 131             if (pthread_mutex_trylock(m) == EBUSY) {            \
 132                 if (timeout == -1 || elapsed >= timeout) {      \
 133                     rc = GPG_ERR_LOCKED;                        \
 134                     break;                                      \
 135                 }                                               \
 136                 select (0, NULL, NULL, NULL, &tv);              \
 137                 if (ctx && ka && elapsed && !((elapsed+1*10) % (ka*10))) { \
 138                   rc = send_status (ctx, STATUS_KEEPALIVE, NULL); \
 139                   if (rc)                                       \
 140                     break;                                      \
 141                 }                                               \
 142             }                                                   \
 143             else {                                              \
 144                 MUTEX_LOCK_DEBUG(m);                            \
 145                 break;                                          \
 146             }                                                   \
 147         }                                                       \
 148     } while (0)
 149
 150 #define MUTEX_TRYLOCK(ctx, m, rc, t) do {                       \
 151         int n;                                                  \
 152         rc = 0;                                                 \
 153         if ((n = pthread_mutex_trylock(m)) == EBUSY) {          \
 154             if (t != -1) {                                      \
 155                 if (ctx)                                        \
 156                   rc = send_status(ctx, STATUS_LOCKED, NULL);   \
 157                 if (!rc && t != 0) {                            \
 158                     MUTEX_TIMED_LOCK(ctx, m, t, rc);            \
 159                 }                                               \
 160                 else if (!rc) {                                 \
 161                     MUTEX_LOCK_DEBUG(m);                        \
 162                 }                                               \
 163             }                                                   \
 164             else                                                \
 165                 rc = GPG_ERR_LOCKED;                            \
 166         }                                                       \
 167         else if (n)                                             \
 168             rc = gpg_error_from_errno(n);                       \
 169         else                                                    \
 170             MUTEX_LOCK_DEBUG(m);                                \
 171     } while (0)
 172
 173 #endif