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 #include "cache.h"
  11
  12 const int NOLOCK = -1;
  13
  14 char *cache_safe_filename(const char *unsafe)
  15 {
  16         static char buf[4][PATH_MAX];
  17         static int bufidx;
  18         char *s;
  19         char c;
  20
  21         bufidx++;
  22         bufidx &= 3;
  23         s = buf[bufidx];
  24
  25         while(unsafe && (c = *unsafe++) != 0) {
  26                 if (c == '/' || c == ' ' || c == '&' || c == '|' ||
  27                     c == '>' || c == '<' || c == '.')
  28                         c = '_';
  29                 *s++ = c;
  30         }
  31         *s = '\0';
  32         return buf[bufidx];
  33 }
  34
  35 int cache_exist(struct cacheitem *item)
  36 {
  37         if (stat(item->name, &item->st)) {
  38                 item->st.st_mtime = 0;
  39                 return 0;
  40         }
  41         return 1;
  42 }
  43
  44 int cache_create_dirs()
  45 {
  46         char *path;
  47
  48         path = fmt("%s", ctx.cfg.cache_root);
  49         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  50                 return 0;
  51
  52         if (!ctx.repo)
  53                 return 0;
  54
  55         path = fmt("%s/%s", ctx.cfg.cache_root,
  56                    cache_safe_filename(ctx.repo->url));
  57
  58         if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  59                 return 0;
  60
  61         if (ctx.qry.page) {
  62                 path = fmt("%s/%s/%s", ctx.cfg.cache_root,
  63                            cache_safe_filename(ctx.repo->url),
  64                            ctx.qry.page);
  65                 if (mkdir(path, S_IRWXU) && errno!=EEXIST)
  66                         return 0;
  67         }
  68         return 1;
  69 }
  70
  71 int cache_refill_overdue(const char *lockfile)
  72 {
  73         struct stat st;
  74
  75         if (stat(lockfile, &st))
  76                 return 0;
  77         else
  78                 return (time(NULL) - st.st_mtime > ctx.cfg.cache_max_create_time);
  79 }
  80
  81 int cache_lock(struct cacheitem *item)
  82 {
  83         int i = 0;
  84         char *lockfile = xstrdup(fmt("%s.lock", item->name));
  85
  86  top:
  87         if (++i > ctx.cfg.max_lock_attempts)
  88                 die("cache_lock: unable to lock %s: %s",
  89                     item->name, strerror(errno));
  90
  91         item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
  92
  93         if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
  94                 goto top;
  95
  96         if (item->fd == NOLOCK && errno == EEXIST &&
  97             cache_refill_overdue(lockfile) && !unlink(lockfile))
  98                         goto top;
  99
 100         free(lockfile);
 101         return (item->fd > 0);
 102 }
 103
 104 int cache_unlock(struct cacheitem *item)
 105 {
 106         close(item->fd);
 107         return (rename(fmt("%s.lock", item->name), item->name) == 0);
 108 }
 109
 110 int cache_cancel_lock(struct cacheitem *item)
 111 {
 112         return (unlink(fmt("%s.lock", item->name)) == 0);
 113 }
 114
 115 int cache_expired(struct cacheitem *item)
 116 {
 117         if (item->ttl < 0)
 118                 return 0;
 119         return item->st.st_mtime + item->ttl * 60 < time(NULL);
 120 }