src/cache.h

   1 /* vim:tw=78:ts=8:sw=4:set ft=c:  */
   2 /*
   3     Copyright (C) 2006-2007 Ben Kibbey <bjk@luxsci.net>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19 #ifndef CACHE_H
  20 #define CACHE_H
  21
  22 #include <pthread.h>
  23
  24 /*
  25  * The mutex is stored at the end of the shared memory.
  26  */
  27 #define MUTEX_OFFSET    cache_size - sizeof(pthread_mutex_t)
  28
  29 #ifdef DEBUG
  30 #define MUTEX_LOCK_CPP          log_write("LOCK %s", __FUNCTION__);
  31 #define MUTEX_UNLOCK_CPP        log_write("UNLOCK %s", __FUNCTION__);
  32 #else
  33 #define MUTEX_LOCK_CPP
  34 #define MUTEX_UNLOCK_CPP
  35 #endif
  36
  37 /*
  38  * pthread_mutex_trylock() doesn't like the pointer (cache_mutexp). The other
  39  * functions seem to work. This should be fine because it won't modify the
  40  * mutex.
  41  */
  42 #define MUTEX_TRYLOCK(ctx)      memcpy(&cache_mutex, shm_data + MUTEX_OFFSET, sizeof(cache_mutex)); \
  43                                 if (ctx && pthread_mutex_trylock(&cache_mutex) == EBUSY) { \
  44                                     assuan_write_status(ctx, "LOCKED", N_("Waiting for lock")); \
  45                                     pthread_mutex_lock(cache_mutexp); \
  46                                 } \
  47                                 else \
  48                                     pthread_mutex_lock(cache_mutexp);
  49
  50 #define MUTEX_LOCK(ctx) MUTEX_LOCK_CPP MUTEX_TRYLOCK(ctx) \
  51                         is_locked = TRUE
  52
  53 #define MUTEX_UNLOCK    MUTEX_UNLOCK_CPP \
  54                         if (is_locked == TRUE) { \
  55                             pthread_mutex_unlock(cache_mutexp); \
  56                             is_locked = FALSE; \
  57                         }
  58
  59 typedef struct {
  60     guchar filename[16];        // MD5
  61     guchar key[32];             // SHA256/AES256/gcrykeysize
  62     gboolean used;
  63     glong timeout;
  64     glong reset;
  65 } file_cache_t;
  66
  67 void *shm_data;
  68 glong cache_size;
  69 pthread_mutex_t cache_mutex;
  70 pthread_mutex_t *cache_mutexp;
  71 gboolean is_locked;
  72
  73 void cache_adjust_timer(void);
  74 gboolean cache_set_timeout(const guchar *md5filename, glong timeout);
  75 gboolean cache_reset_timeout(const guchar *md5filename, glong timeout);
  76 gboolean cache_iscached(const guchar *md5filename);
  77 gboolean cache_clear(const guchar *md5filename, gint which);
  78 gboolean cache_add_file(const guchar *md5file, const guchar *shakey);
  79 gboolean cache_get_key(const guchar *md5file, guchar *shakey);
  80 gboolean cache_update_key(const guchar *md5filename, const guchar *shakey);
  81 gint cache_file_count(void);
  82 gboolean cache_has_file(const guchar *md5file);
  83
  84 #endif