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
37 int blkid_debug_mask = 0;
38
39
safe_getenv(const char * arg)40 static 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 */
64 static 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
blkid_get_cache(blkid_cache * ret_cache,const char * filename)83 int 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
blkid_put_cache(blkid_cache cache)120 void 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
blkid_gc_cache(blkid_cache cache)159 void 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
main(int argc,char ** argv)185 int 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