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[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
 29int 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
 38int 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
 62int 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
 72int 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
 95int cache_unlock(struct cacheitem *item)
 96{
 97	close(item->fd);
 98	return (rename(fmt("%s.lock", item->name), item->name) == 0);
 99}
100
101int cache_cancel_lock(struct cacheitem *item)
102{
103	return (unlink(fmt("%s.lock", item->name)) == 0);
104}
105
106int 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}