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
 11const int NOLOCK = -1;
 12
 13char *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
 34int 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
 43int 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 (cgit_query_page) {
 61		path = fmt("%s/%s/%s", cgit_cache_root,
 62			   cache_safe_filename(cgit_repo->url),
 63			   cgit_query_page);
 64		if (mkdir(path, S_IRWXU) && errno!=EEXIST)
 65			return 0;
 66	}
 67	return 1;
 68}
 69
 70int 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
 80int 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
103int cache_unlock(struct cacheitem *item)
104{
105	close(item->fd);
106	return (rename(fmt("%s.lock", item->name), item->name) == 0);
107}
108
109int cache_cancel_lock(struct cacheitem *item)
110{
111	return (unlink(fmt("%s.lock", item->name)) == 0);
112}
113
114int 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}