cache.c revision 78c7d0efae91cde1a992f69c1a0157b39e971670 
1/*
2 * cache.c - allocation/initialization/free routines for cache
3 *
4 * Copyright (C) 2001 Andreas Dilger
5 * Copyright (C) 2003 Theodore Ts'o
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the
9 * GNU Lesser General Public License.
10 * %End-Header%
11 */
12
13#if HAVE_UNISTD_H
14#include <unistd.h>
15#endif
16#ifdef HAVE_ERRNO_H
17#include <errno.h>
18#endif
19#include <stdlib.h>
20#include <string.h>
21#ifdef HAVE_SYS_PRCTL_H
22#include <sys/prctl.h>
23#else
24#define PR_GET_DUMPABLE 3
25#endif
26#if (!defined(HAVE_PRCTL) && defined(linux))
27#include <sys/syscall.h>
28#endif
29#include "blkidP.h"
30
31int blkid_debug_mask = 0;
32
33
34static char *safe_getenv(const char *arg)
35{
36	if ((getuid() != geteuid()) || (getgid() != getegid()))
37		return NULL;
38#if HAVE_PRCTL
39	if (prctl(PR_GET_DUMPABLE) == 0)
40		return NULL;
41#else
42#if (defined(linux) && defined(SYS_prctl))
43	if (syscall(SYS_prctl, PR_GET_DUMPABLE) == 0)
44		return NULL;
45#endif
46#endif
47
48#ifdef HAVE___SECURE_GETENV
49	return __secure_getenv("BLKID_FILE");
50#else
51	return getenv("BLKID_FILE");
52#endif
53}
54
55#if 0 /* ifdef CONFIG_BLKID_DEBUG */
56static blkid_debug_dump_cache(int mask, blkid_cache cache)
57{
58	struct list_head *p;
59
60	if (!cache) {
61		printf("cache: NULL\n");
62		return;
63	}
64
65	printf("cache: time = %lu\n", cache->bic_time);
66	printf("cache: flags = 0x%08X\n", cache->bic_flags);
67
68	list_for_each(p, &cache->bic_devs) {
69		blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
70		blkid_debug_dump_dev(dev);
71	}
72}
73#endif
74
75int blkid_get_cache(blkid_cache *ret_cache, const char *filename)
76{
77	blkid_cache cache;
78
79#ifdef CONFIG_BLKID_DEBUG
80	if (!(blkid_debug_mask & DEBUG_INIT)) {
81		char *dstr = getenv("BLKID_DEBUG");
82
83		if (dstr)
84			blkid_debug_mask = strtoul(dstr, 0, 0);
85		blkid_debug_mask |= DEBUG_INIT;
86	}
87#endif
88
89	DBG(DEBUG_CACHE, printf("creating blkid cache (using %s)\n",
90				filename ? filename : "default cache"));
91
92	if (!(cache = (blkid_cache) calloc(1, sizeof(struct blkid_struct_cache))))
93		return -BLKID_ERR_MEM;
94
95	INIT_LIST_HEAD(&cache->bic_devs);
96	INIT_LIST_HEAD(&cache->bic_tags);
97
98	if (filename && !strlen(filename))
99		filename = 0;
100	if (!filename)
101		filename = safe_getenv("BLKID_FILE");
102	if (!filename)
103		filename = BLKID_CACHE_FILE;
104	cache->bic_filename = blkid_strdup(filename);
105
106	blkid_read_cache(cache);
107
108	*ret_cache = cache;
109	return 0;
110}
111
112void blkid_put_cache(blkid_cache cache)
113{
114	if (!cache)
115		return;
116
117	(void) blkid_flush_cache(cache);
118
119	DBG(DEBUG_CACHE, printf("freeing cache struct\n"));
120
121	/* DBG(DEBUG_CACHE, blkid_debug_dump_cache(cache)); */
122
123	while (!list_empty(&cache->bic_devs)) {
124		blkid_dev dev = list_entry(cache->bic_devs.next,
125					   struct blkid_struct_dev,
126					    bid_devs);
127		blkid_free_dev(dev);
128	}
129
130	while (!list_empty(&cache->bic_tags)) {
131		blkid_tag tag = list_entry(cache->bic_tags.next,
132					   struct blkid_struct_tag,
133					   bit_tags);
134
135		while (!list_empty(&tag->bit_names)) {
136			blkid_tag bad = list_entry(tag->bit_names.next,
137						   struct blkid_struct_tag,
138						   bit_names);
139
140			DBG(DEBUG_CACHE, printf("warning: unfreed tag %s=%s\n",
141						bad->bit_name, bad->bit_val));
142			blkid_free_tag(bad);
143		}
144		blkid_free_tag(tag);
145	}
146	if (cache->bic_filename)
147		free(cache->bic_filename);
148
149	free(cache);
150}
151
152#ifdef TEST_PROGRAM
153int main(int argc, char** argv)
154{
155	blkid_cache cache = NULL;
156	int ret;
157
158	blkid_debug_mask = DEBUG_ALL;
159	if ((argc > 2)) {
160		fprintf(stderr, "Usage: %s [filename] \n", argv[0]);
161		exit(1);
162	}
163
164	if ((ret = blkid_get_cache(&cache, argv[1])) < 0) {
165		fprintf(stderr, "error %d parsing cache file %s\n", ret,
166			argv[1] ? argv[1] : BLKID_CACHE_FILE);
167		exit(1);
168	}
169	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
170		fprintf(stderr, "%s: error creating cache (%d)\n",
171			argv[0], ret);
172		exit(1);
173	}
174	if ((ret = blkid_probe_all(cache) < 0))
175		fprintf(stderr, "error probing devices\n");
176
177	blkid_put_cache(cache);
178
179	return ret;
180}
181#endif
182