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_query_repo)
  47                 return 0;
  48
  49         path = fmt("%s/%s", cgit_cache_root, cgit_query_repo);
  50         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  51                 return 0;
  52
  53         if (cgit_query_page) {
  54                 path = fmt("%s/%s/%s", cgit_cache_root, cgit_query_repo,
  55                            cgit_query_page);
  56                 if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  57                         return 0;
  58         }
  59         return 1;
  60 }
  61
  62 int cache_refill_overdue(const char *lockfile)
  63 {
  64         struct stat st;
  65
  66         if (stat(lockfile, &st))
  67                 return 0;
  68         else
  69                 return (time(NULL) - st.st_mtime > cgit_cache_max_create_time);
  70 }
  71
  72 int cache_lock(struct cacheitem *item)
  73 {
  74         int i = 0;
  75         char *lockfile = xstrdup(fmt("%s.lock", item->name));
  76
  77  top:
  78         if (++i > cgit_max_lock_attempts)
  79                 die("cache_lock: unable to lock %s: %s",
  80                     item->name, strerror(errno));
  81
  82         item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
  83
  84         if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
  85                 goto top;
  86
  87         if (item->fd == NOLOCK && errno == EEXIST &&
  88             cache_refill_overdue(lockfile) && !unlink(lockfile))
  89                         goto top;
  90
  91         free(lockfile);
  92         return (item->fd > 0);
  93 }
  94
  95 int cache_unlock(struct cacheitem *item)
  96 {
  97         close(item->fd);
  98         return (rename(fmt("%s.lock", item->name), item->name) == 0);
  99 }
 100
 101 int cache_cancel_lock(struct cacheitem *item)
 102 {
 103         return (unlink(fmt("%s.lock", item->name)) == 0);
 104 }
 105
 106 int cache_expired(struct cacheitem *item)
 107 {
 108         if (item->ttl < 0)
 109                 return 0;
 110         return item->st.st_mtime + item->ttl * 60 < time(NULL);
 111 }