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_repo)
 47		return 0;
 48
 49	path = fmt("%s/%s", cgit_cache_root,
 50		   cache_safe_filename(cgit_repo->url));
 51
 52	if (mkdir(path, S_IRWXU) && errno!=EEXIST)
 53		return 0;
 54
 55	if (cgit_query_page) {
 56		path = fmt("%s/%s/%s", cgit_cache_root,
 57			   cache_safe_filename(cgit_repo->url),
 58			   cgit_query_page);
 59		if (mkdir(path, S_IRWXU) && errno!=EEXIST)
 60			return 0;
 61	}
 62	return 1;
 63}
 64
 65int cache_refill_overdue(const char *lockfile)
 66{
 67	struct stat st;
 68
 69	if (stat(lockfile, &st))
 70		return 0;
 71	else
 72		return (time(NULL) - st.st_mtime > cgit_cache_max_create_time);
 73}
 74
 75int cache_lock(struct cacheitem *item)
 76{
 77	int i = 0;
 78	char *lockfile = xstrdup(fmt("%s.lock", item->name));
 79
 80 top:
 81	if (++i > cgit_max_lock_attempts)
 82		die("cache_lock: unable to lock %s: %s",
 83		    item->name, strerror(errno));
 84
 85       	item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
 86
 87	if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
 88		goto top;
 89
 90	if (item->fd == NOLOCK && errno == EEXIST &&
 91	    cache_refill_overdue(lockfile) && !unlink(lockfile))
 92			goto top;
 93
 94	free(lockfile);
 95	return (item->fd > 0);
 96}
 97
 98int cache_unlock(struct cacheitem *item)
 99{
100	close(item->fd);
101	return (rename(fmt("%s.lock", item->name), item->name) == 0);
102}
103
104int cache_cancel_lock(struct cacheitem *item)
105{
106	return (unlink(fmt("%s.lock", item->name)) == 0);
107}
108
109int cache_expired(struct cacheitem *item)
110{
111	if (item->ttl < 0)
112		return 0;
113	return item->st.st_mtime + item->ttl * 60 < time(NULL);
114}