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
13void cache_prepare(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}
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	if (!cgit_query_repo)
49		return 0;
50
51	path = fmt("%s/%s", cgit_cache_root, cgit_query_repo);
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, cgit_query_repo, 
57			   cgit_query_page);
58		if (mkdir(path, S_IRWXU) && errno!=EEXIST)
59			return 0;
60	}
61	return 1;
62}
63
64int cache_lock(struct cacheitem *item)
65{
66	int ret;
67	char *lockfile = fmt("%s.lock", item->name);
68
69 top:  
70       	item->fd = open(lockfile, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR|S_IWUSR);
71	if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
72		goto top;
73	if (item->fd == NOLOCK && errno == EEXIST) {
74		struct stat st;
75		time_t t;
76		if (stat(lockfile, &st))
77			return ret;
78		t = time(NULL);
79		if (t-st.st_mtime > cgit_cache_max_create_time && 
80		    !unlink(lockfile))
81			goto top;
82		return 0;
83	}
84	return (item->fd > 0);
85}
86
87int cache_unlock(struct cacheitem *item)
88{
89	close(item->fd);
90	return (rename(fmt("%s.lock", item->name), item->name) == 0);
91}
92
93int cache_expired(struct cacheitem *item)
94{
95	if (item->ttl < 0)
96		return 0;
97	return item->st.st_mtime + item->ttl * 60 < time(NULL);
98}