cache.c revision 18a1444b4f1e6a0948fd38fa0de382d86cfe04de 
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_SECURE_GETENV
14#define _GNU_SOURCE
15#endif
16#if HAVE_UNISTD_H
17#include <unistd.h>
18#endif
19#ifdef HAVE_ERRNO_H
20#include <errno.h>
21#endif
22#include <stdlib.h>
23#include <string.h>
24#ifdef HAVE_SYS_PRCTL_H
25#include <sys/prctl.h>
26#else
27#define PR_GET_DUMPABLE 3
28#endif
29#if (!defined(HAVE_PRCTL) && defined(linux))
30#include <sys/syscall.h>
31#endif
32#ifdef HAVE_SYS_STAT_H
33#include <sys/stat.h>
34#endif
35#include "blkidP.h"
36
37int blkid_debug_mask = 0;
38
39
40static char *safe_getenv(const char *arg)
41{
42	if ((getuid() != geteuid()) || (getgid() != getegid()))
43		return NULL;
44#if HAVE_PRCTL
45	if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
46		return NULL;
47#else
48#if (defined(linux) && defined(SYS_prctl))
49	if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
50		return NULL;
51#endif
52#endif
53
54#if defined(HAVE_SECURE_GETENV)
55	return secure_getenv(arg);
56#elif defined(HAVE___SECURE_GETENV)
57	return __secure_getenv(arg);
58#else
59	return getenv(arg);
60#endif
61}
62
63#if 0 /* ifdef CONFIG_BLKID_DEBUG */
64static blkid_debug_dump_cache(int mask, blkid_cache cache)
65{
66	struct list_head *p;
67
68	if (!cache) {
69		printf("cache: NULL\n");
70		return;
71	}
72
73	printf("cache: time = %lu\n", cache->bic_time);
74	printf("cache: flags = 0x%08X\n", cache->bic_flags);
75
76	list_for_each(p, &cache->bic_devs) {
77		blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
78		blkid_debug_dump_dev(dev);
79	}
80}
81#endif
82
83int blkid_get_cache(blkid_cache *ret_cache, const char *filename)
84{
85	blkid_cache cache;
86
87#ifdef CONFIG_BLKID_DEBUG
88	if (!(blkid_debug_mask & DEBUG_INIT)) {
89		char *dstr = getenv("BLKID_DEBUG");
90
91		if (dstr)
92			blkid_debug_mask = strtoul(dstr, 0, 0);
93		blkid_debug_mask |= DEBUG_INIT;
94	}
95#endif
96
97	DBG(DEBUG_CACHE, printf("creating blkid cache (using %s)\n",
98				filename ? filename : "default cache"));
99
100	if (!(cache = (blkid_cache) calloc(1, sizeof(struct blkid_struct_cache))))
101		return -BLKID_ERR_MEM;
102
103	INIT_LIST_HEAD(&cache->bic_devs);
104	INIT_LIST_HEAD(&cache->bic_tags);
105
106	if (filename && !strlen(filename))
107		filename = 0;
108	if (!filename)
109		filename = safe_getenv("BLKID_FILE");
110	if (!filename)
111		filename = BLKID_CACHE_FILE;
112	cache->bic_filename = blkid_strdup(filename);
113
114	blkid_read_cache(cache);
115
116	*ret_cache = cache;
117	return 0;
118}
119
120void blkid_put_cache(blkid_cache cache)
121{
122	if (!cache)
123		return;
124
125	(void) blkid_flush_cache(cache);
126
127	DBG(DEBUG_CACHE, printf("freeing cache struct\n"));
128
129	/* DBG(DEBUG_CACHE, blkid_debug_dump_cache(cache)); */
130
131	while (!list_empty(&cache->bic_devs)) {
132		blkid_dev dev = list_entry(cache->bic_devs.next,
133					   struct blkid_struct_dev,
134					    bid_devs);
135		blkid_free_dev(dev);
136	}
137
138	while (!list_empty(&cache->bic_tags)) {
139		blkid_tag tag = list_entry(cache->bic_tags.next,
140					   struct blkid_struct_tag,
141					   bit_tags);
142
143		while (!list_empty(&tag->bit_names)) {
144			blkid_tag bad = list_entry(tag->bit_names.next,
145						   struct blkid_struct_tag,
146						   bit_names);
147
148			DBG(DEBUG_CACHE, printf("warning: unfreed tag %s=%s\n",
149						bad->bit_name, bad->bit_val));
150			blkid_free_tag(bad);
151		}
152		blkid_free_tag(tag);
153	}
154	free(cache->bic_filename);
155
156	free(cache);
157}
158
159void blkid_gc_cache(blkid_cache cache)
160{
161	struct list_head *p, *pnext;
162	struct stat st;
163
164	if (!cache)
165		return;
166
167	list_for_each_safe(p, pnext, &cache->bic_devs) {
168		blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
169		if (!p)
170			break;
171		if (stat(dev->bid_name, &st) < 0) {
172			DBG(DEBUG_CACHE,
173			    printf("freeing %s\n", dev->bid_name));
174			blkid_free_dev(dev);
175			cache->bic_flags |= BLKID_BIC_FL_CHANGED;
176		} else {
177			DBG(DEBUG_CACHE,
178			    printf("Device %s exists\n", dev->bid_name));
179		}
180	}
181}
182
183
184#ifdef TEST_PROGRAM
185int main(int argc, char** argv)
186{
187	blkid_cache cache = NULL;
188	int ret;
189
190	blkid_debug_mask = DEBUG_ALL;
191	if ((argc > 2)) {
192		fprintf(stderr, "Usage: %s [filename] \n", argv[0]);
193		exit(1);
194	}
195
196	if ((ret = blkid_get_cache(&cache, argv[1])) < 0) {
197		fprintf(stderr, "error %d parsing cache file %s\n", ret,
198			argv[1] ? argv[1] : BLKID_CACHE_FILE);
199		exit(1);
200	}
201	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
202		fprintf(stderr, "%s: error creating cache (%d)\n",
203			argv[0], ret);
204		exit(1);
205	}
206	if ((ret = blkid_probe_all(cache) < 0))
207		fprintf(stderr, "error probing devices\n");
208
209	blkid_put_cache(cache);
210
211	return ret;
212}
213#endif
214