cache.c revision a6ce1349539f866334ef3d5758bc2ee44a454acd 
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#ifdef HAVE_SYS_STAT_H
30#include <sys/stat.h>
31#endif
32#include "blkidP.h"
33
34int blkid_debug_mask = 0;
35
36
37static char *safe_getenv(const char *arg)
38{
39	if ((getuid() != geteuid()) || (getgid() != getegid()))
40		return NULL;
41#if HAVE_PRCTL
42	if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
43		return NULL;
44#else
45#if (defined(linux) && defined(SYS_prctl))
46	if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
47		return NULL;
48#endif
49#endif
50
51#ifdef HAVE___SECURE_GETENV
52	return __secure_getenv(arg);
53#else
54	return getenv(arg);
55#endif
56}
57
58#if 0 /* ifdef CONFIG_BLKID_DEBUG */
59static blkid_debug_dump_cache(int mask, blkid_cache cache)
60{
61	struct list_head *p;
62
63	if (!cache) {
64		printf("cache: NULL\n");
65		return;
66	}
67
68	printf("cache: time = %lu\n", cache->bic_time);
69	printf("cache: flags = 0x%08X\n", cache->bic_flags);
70
71	list_for_each(p, &cache->bic_devs) {
72		blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
73		blkid_debug_dump_dev(dev);
74	}
75}
76#endif
77
78int blkid_get_cache(blkid_cache *ret_cache, const char *filename)
79{
80	blkid_cache cache;
81
82#ifdef CONFIG_BLKID_DEBUG
83	if (!(blkid_debug_mask & DEBUG_INIT)) {
84		char *dstr = getenv("BLKID_DEBUG");
85
86		if (dstr)
87			blkid_debug_mask = strtoul(dstr, 0, 0);
88		blkid_debug_mask |= DEBUG_INIT;
89	}
90#endif
91
92	DBG(DEBUG_CACHE, printf("creating blkid cache (using %s)\n",
93				filename ? filename : "default cache"));
94
95	if (!(cache = (blkid_cache) calloc(1, sizeof(struct blkid_struct_cache))))
96		return -BLKID_ERR_MEM;
97
98	INIT_LIST_HEAD(&cache->bic_devs);
99	INIT_LIST_HEAD(&cache->bic_tags);
100
101	if (filename && !strlen(filename))
102		filename = 0;
103	if (!filename)
104		filename = safe_getenv("BLKID_FILE");
105	if (!filename)
106		filename = BLKID_CACHE_FILE;
107	cache->bic_filename = blkid_strdup(filename);
108
109	blkid_read_cache(cache);
110
111	*ret_cache = cache;
112	return 0;
113}
114
115void blkid_put_cache(blkid_cache cache)
116{
117	if (!cache)
118		return;
119
120	(void) blkid_flush_cache(cache);
121
122	DBG(DEBUG_CACHE, printf("freeing cache struct\n"));
123
124	/* DBG(DEBUG_CACHE, blkid_debug_dump_cache(cache)); */
125
126	while (!list_empty(&cache->bic_devs)) {
127		blkid_dev dev = list_entry(cache->bic_devs.next,
128					   struct blkid_struct_dev,
129					    bid_devs);
130		blkid_free_dev(dev);
131	}
132
133	while (!list_empty(&cache->bic_tags)) {
134		blkid_tag tag = list_entry(cache->bic_tags.next,
135					   struct blkid_struct_tag,
136					   bit_tags);
137
138		while (!list_empty(&tag->bit_names)) {
139			blkid_tag bad = list_entry(tag->bit_names.next,
140						   struct blkid_struct_tag,
141						   bit_names);
142
143			DBG(DEBUG_CACHE, printf("warning: unfreed tag %s=%s\n",
144						bad->bit_name, bad->bit_val));
145			blkid_free_tag(bad);
146		}
147		blkid_free_tag(tag);
148	}
149	free(cache->bic_filename);
150
151	free(cache);
152}
153
154void blkid_gc_cache(blkid_cache cache)
155{
156	struct list_head *p, *pnext;
157	struct stat st;
158
159	if (!cache)
160		return;
161
162	list_for_each_safe(p, pnext, &cache->bic_devs) {
163		blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
164		if (!p)
165			break;
166		if (stat(dev->bid_name, &st) < 0) {
167			DBG(DEBUG_CACHE,
168			    printf("freeing %s\n", dev->bid_name));
169			blkid_free_dev(dev);
170			cache->bic_flags |= BLKID_BIC_FL_CHANGED;
171		} else {
172			DBG(DEBUG_CACHE,
173			    printf("Device %s exists\n", dev->bid_name));
174		}
175	}
176}
177
178
179#ifdef TEST_PROGRAM
180int main(int argc, char** argv)
181{
182	blkid_cache cache = NULL;
183	int ret;
184
185	blkid_debug_mask = DEBUG_ALL;
186	if ((argc > 2)) {
187		fprintf(stderr, "Usage: %s [filename] \n", argv[0]);
188		exit(1);
189	}
190
191	if ((ret = blkid_get_cache(&cache, argv[1])) < 0) {
192		fprintf(stderr, "error %d parsing cache file %s\n", ret,
193			argv[1] ? argv[1] : BLKID_CACHE_FILE);
194		exit(1);
195	}
196	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
197		fprintf(stderr, "%s: error creating cache (%d)\n",
198			argv[0], ret);
199		exit(1);
200	}
201	if ((ret = blkid_probe_all(cache) < 0))
202		fprintf(stderr, "error probing devices\n");
203
204	blkid_put_cache(cache);
205
206	return ret;
207}
208#endif
209