cache.c

   1 /* cache.c: cache management
   2  *
   3  * Copyright (C) 2006 Lars Hjemli
   4  *
   5  * Licensed under GNU General Public License v2
   6  *   (see COPYING for full license text)
   7  */
   8
   9 #include "cgit.h"
  10
  11 const int NOLOCK = -1;
  12
  13 char *cache_safe_filename(const char *unsafe)
  14 {
  15         static char buf[PATH_MAX];
  16         char *s = buf;
  17         char c;
  18
  19         while(unsafe && (c = *unsafe++) != 0) {
  20                 if (c == '/' || c == ' ' || c == '&' || c == '|' ||
  21                     c == '>' || c == '<' || c == '.')
  22                         c = '_';
  23                 *s++ = c;
  24         }
  25         *s = '\0';
  26         return buf;
  27 }
  28
  29 int cache_exist(struct cacheitem *item)
  30 {
  31         if (stat(item->name, &item->st)) {
  32                 item->st.st_mtime = 0;
  33                 return 0;
  34         }
  35         return 1;
  36 }
  37
  38 int cache_create_dirs()
  39 {
  40         char *path;
  41
  42         path = fmt("%s", cgit_cache_root);
  43         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  44                 return 0;
  45
  46         if (!cgit_repo)
  47                 return 0;
  48
  49         path = fmt("%s/%s", cgit_cache_root,
  50                    cache_safe_filename(cgit_repo->url));
  51
  52         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  53                 return 0;
  54
  55         if (cgit_query_page) {
  56                 path = fmt("%s/%s/%s", cgit_cache_root,
  57                            cache_safe_filename(cgit_repo->url),
  58                            cgit_query_page);
  59                 if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  60                         return 0;
  61         }
  62         return 1;
  63 }
  64
  65 int cache_refill_overdue(const char *lockfile)
  66 {
  67         struct stat st;
  68
  69         if (stat(lockfile, &st))
  70                 return 0;
  71         else
  72                 return (time(NULL) - st.st_mtime > cgit_cache_max_create_time);
  73 }
  74
  75 int cache_lock(struct cacheitem *item)
  76 {
  77         int i = 0;
  78         char *lockfile = xstrdup(fmt("%s.lock", item->name));
  79
  80  top:
  81         if (++i > cgit_max_lock_attempts)
  82                 die("cache_lock: unable to lock %s: %s",
  83                     item->name, strerror(errno));
  84
  85         item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
  86
  87         if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
  88                 goto top;
  89
  90         if (item->fd == NOLOCK && errno == EEXIST &&
  91             cache_refill_overdue(lockfile) && !unlink(lockfile))
  92                         goto top;
  93
  94         free(lockfile);
  95         return (item->fd > 0);
  96 }
  97
  98 int cache_unlock(struct cacheitem *item)
  99 {
 100         close(item->fd);
 101         return (rename(fmt("%s.lock", item->name), item->name) == 0);
 102 }
 103
 104 int cache_cancel_lock(struct cacheitem *item)
 105 {
 106         return (unlink(fmt("%s.lock", item->name)) == 0);
 107 }
 108
 109 int cache_expired(struct cacheitem *item)
 110 {
 111         if (item->ttl < 0)
 112                 return 0;
 113         return item->st.st_mtime + item->ttl * 60 < time(NULL);
 114 }