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[4][PATH_MAX];
  16         static int bufidx;
  17         char *s;
  18         char c;
  19
  20         bufidx++;
  21         bufidx &= 3;
  22         s = buf[bufidx];
  23
  24         while(unsafe && (c = *unsafe++) != 0) {
  25                 if (c == '/' || c == ' ' || c == '&' || c == '|' ||
  26                     c == '>' || c == '<' || c == '.')
  27                         c = '_';
  28                 *s++ = c;
  29         }
  30         *s = '\0';
  31         return buf[bufidx];
  32 }
  33
  34 int cache_exist(struct cacheitem *item)
  35 {
  36         if (stat(item->name, &item->st)) {
  37                 item->st.st_mtime = 0;
  38                 return 0;
  39         }
  40         return 1;
  41 }
  42
  43 int cache_create_dirs()
  44 {
  45         char *path;
  46
  47         path = fmt("%s", cgit_cache_root);
  48         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  49                 return 0;
  50
  51         if (!cgit_repo)
  52                 return 0;
  53
  54         path = fmt("%s/%s", cgit_cache_root,
  55                    cache_safe_filename(cgit_repo->url));
  56
  57         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  58                 return 0;
  59
  60         if (ctx.qry.page) {
  61                 path = fmt("%s/%s/%s", cgit_cache_root,
  62                            cache_safe_filename(cgit_repo->url),
  63                            ctx.qry.page);
  64                 if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  65                         return 0;
  66         }
  67         return 1;
  68 }
  69
  70 int cache_refill_overdue(const char *lockfile)
  71 {
  72         struct stat st;
  73
  74         if (stat(lockfile, &st))
  75                 return 0;
  76         else
  77                 return (time(NULL) - st.st_mtime > cgit_cache_max_create_time);
  78 }
  79
  80 int cache_lock(struct cacheitem *item)
  81 {
  82         int i = 0;
  83         char *lockfile = xstrdup(fmt("%s.lock", item->name));
  84
  85  top:
  86         if (++i > cgit_max_lock_attempts)
  87                 die("cache_lock: unable to lock %s: %s",
  88                     item->name, strerror(errno));
  89
  90         item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
  91
  92         if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
  93                 goto top;
  94
  95         if (item->fd == NOLOCK && errno == EEXIST &&
  96             cache_refill_overdue(lockfile) && !unlink(lockfile))
  97                         goto top;
  98
  99         free(lockfile);
 100         return (item->fd > 0);
 101 }
 102
 103 int cache_unlock(struct cacheitem *item)
 104 {
 105         close(item->fd);
 106         return (rename(fmt("%s.lock", item->name), item->name) == 0);
 107 }
 108
 109 int cache_cancel_lock(struct cacheitem *item)
 110 {
 111         return (unlink(fmt("%s.lock", item->name)) == 0);
 112 }
 113
 114 int cache_expired(struct cacheitem *item)
 115 {
 116         if (item->ttl < 0)
 117                 return 0;
 118         return item->st.st_mtime + item->ttl * 60 < time(NULL);
 119 }