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
34 int blkid_debug_mask = 0;
35
36
safe_getenv(const char * arg)37 static 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 */
59 static 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
blkid_get_cache(blkid_cache * ret_cache,const char * filename)78 int 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
blkid_put_cache(blkid_cache cache)115 void 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
blkid_gc_cache(blkid_cache cache)154 void 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
main(int argc,char ** argv)180 int 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