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
13int cache_lookup(struct cacheitem *item)
14{
15	if (!cgit_query_repo) {
16		item->name = xstrdup(fmt("%s/index.html", cgit_cache_root));
17		item->ttl = cgit_cache_root_ttl;
18	} else if (!cgit_query_page) {
19		item->name = xstrdup(fmt("%s/%s/index.html", cgit_cache_root, 
20			   cgit_query_repo));
21		item->ttl = cgit_cache_repo_ttl;
22	} else {
23		item->name = xstrdup(fmt("%s/%s/%s/%s.html", cgit_cache_root, 
24			   cgit_query_repo, cgit_query_page, 
25			   cgit_querystring));
26		if (cgit_query_has_symref)
27			item->ttl = cgit_cache_dynamic_ttl;
28		else if (cgit_query_has_sha1)
29			item->ttl = cgit_cache_static_ttl;
30		else
31			item->ttl = cgit_cache_repo_ttl;
32	}
33	if (stat(item->name, &item->st)) {
34		item->st.st_mtime = 0;
35		return 0;
36	}
37	return 1;
38}
39
40int cache_create_dirs()
41{
42	char *path;
43
44	if (!cgit_query_repo)
45		return 0;
46
47	path = fmt("%s/%s", cgit_cache_root, cgit_query_repo);
48	if (mkdir(path, S_IRWXU) && errno!=EEXIST)
49		return 0;
50
51	if (cgit_query_page) {
52		path = fmt("%s/%s/%s", cgit_cache_root, cgit_query_repo, 
53			   cgit_query_page);
54		if (mkdir(path, S_IRWXU) && errno!=EEXIST)
55			return 0;
56	}
57	return 1;
58}
59
60int cache_lock(struct cacheitem *item)
61{
62	int ret;
63	char *lockfile = fmt("%s.lock", item->name);
64
65 top:  
66       	item->fd = open(lockfile, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR|S_IWUSR);
67	if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
68		goto top;
69	if (item->fd == NOLOCK && errno == EEXIST) {
70		struct stat st;
71		time_t t;
72		if (stat(lockfile, &st))
73			return ret;
74		t = time(NULL);
75		if (t-st.st_mtime > cgit_cache_max_create_time && 
76		    !unlink(lockfile))
77			goto top;
78		return 0;
79	}
80	return (item->fd > 0);
81}
82
83int cache_unlock(struct cacheitem *item)
84{
85	close(item->fd);
86	return (rename(fmt("%s.lock", item->name), item->name) == 0);
87}
88
89int cache_expired(struct cacheitem *item)
90{
91	if (item->ttl < 0)
92		return 0;
93	return item->st.st_mtime + item->ttl * 60 < time(NULL);
94}