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
 12const int NOLOCK = -1;
 13
 14char *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
 35int 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
 44int 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
 71int 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
 81int 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
104int cache_unlock(struct cacheitem *item)
105{
106	close(item->fd);
107	return (rename(fmt("%s.lock", item->name), item->name) == 0);
108}
109
110int cache_cancel_lock(struct cacheitem *item)
111{
112	return (unlink(fmt("%s.lock", item->name)) == 0);
113}
114
115int 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}