1 /*
2 * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
3 *
4 * This file may be redistributed under the terms of the
5 * GNU Lesser General Public License.
6 */
7
8 #include <stdio.h>
9 #include <string.h>
10 #include <stdlib.h>
11 #include <unistd.h>
12 #include <fcntl.h>
13 #include <time.h>
14 #include <sys/time.h>
15 #include <sys/types.h>
16 #ifdef HAVE_SYS_STAT_H
17 #include <sys/stat.h>
18 #endif
19 #ifdef HAVE_ERRNO_H
20 #include <errno.h>
21 #endif
22
23 #include "blkidP.h"
24 #include "sysfs.h"
25
26 static void blkid_probe_to_tags(blkid_probe pr, blkid_dev dev)
27 {
28 const char *data;
29 const char *name;
30 int nvals, n;
31 size_t len;
32
33 nvals = blkid_probe_numof_values(pr);
34
35 for (n = 0; n < nvals; n++) {
36 if (blkid_probe_get_value(pr, n, &name, &data, &len) != 0)
37 continue;
38 if (strncmp(name, "PART_ENTRY_", 11) == 0) {
39 if (strcmp(name, "PART_ENTRY_UUID") == 0)
40 blkid_set_tag(dev, "PARTUUID", data, len);
41 else if (strcmp(name, "PART_ENTRY_NAME") == 0)
42 blkid_set_tag(dev, "PARTLABEL", data, len);
43
44 } else if (!strstr(name, "_ID")) {
45 /* superblock UUID, LABEL, ...
46 * but not {SYSTEM,APPLICATION,..._ID} */
47 blkid_set_tag(dev, name, data, len);
48 }
49 }
50 }
51
52 /*
53 * Verify that the data in dev is consistent with what is on the actual
54 * block device (using the devname field only). Normally this will be
55 * called when finding items in the cache, but for long running processes
56 * is also desirable to revalidate an item before use.
57 *
58 * If we are unable to revalidate the data, we return the old data and
59 * do not set the BLKID_BID_FL_VERIFIED flag on it.
60 */
61 blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
62 {
63 blkid_tag_iterate iter;
64 const char *type, *value;
65 struct stat st;
66 time_t diff, now;
67 int fd;
68
69 if (!dev || !cache)
70 return NULL;
71
72 now = time(NULL);
73 diff = (uintmax_t)now - dev->bid_time;
74
75 if (stat(dev->bid_name, &st) < 0) {
76 DBG(PROBE, ul_debug("blkid_verify: error %s (%d) while "
77 "trying to stat %s", strerror(errno), errno,
78 dev->bid_name));
79 open_err:
80 if ((errno == EPERM) || (errno == EACCES) || (errno == ENOENT)) {
81 /* We don't have read permission, just return cache data. */
82 DBG(PROBE, ul_debug("returning unverified data for %s",
83 dev->bid_name));
84 return dev;
85 }
86 blkid_free_dev(dev);
87 return NULL;
88 }
89
90 if (now >= dev->bid_time &&
91 #ifdef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
92 (st.st_mtime < dev->bid_time ||
93 (st.st_mtime == dev->bid_time &&
94 st.st_mtim.tv_nsec / 1000 <= dev->bid_utime)) &&
95 #else
96 st.st_mtime <= dev->bid_time &&
97 #endif
98 diff >= 0 && diff < BLKID_PROBE_MIN) {
99 dev->bid_flags |= BLKID_BID_FL_VERIFIED;
100 return dev;
101 }
102
103 #ifndef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
104 DBG(PROBE, ul_debug("need to revalidate %s (cache time %lld, stat time %lld,\t"
105 "time since last check %lld)",
106 dev->bid_name, (long long)dev->bid_time,
107 (long long)st.st_mtime, (long long)diff));
108 #else
109 DBG(PROBE, ul_debug("need to revalidate %s (cache time %lld.%lld, stat time %lld.%lld,\t"
110 "time since last check %lld)",
111 dev->bid_name,
112 (long long)dev->bid_time, (long long)dev->bid_utime,
113 (long long)st.st_mtime, (long long)st.st_mtim.tv_nsec / 1000,
114 (long long)diff));
115 #endif
116
117 if (sysfs_devno_is_dm_private(st.st_rdev, NULL)) {
118 blkid_free_dev(dev);
119 return NULL;
120 }
121 if (!cache->probe) {
122 cache->probe = blkid_new_probe();
123 if (!cache->probe) {
124 blkid_free_dev(dev);
125 return NULL;
126 }
127 }
128
129 fd = open(dev->bid_name, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
130 if (fd < 0) {
131 DBG(PROBE, ul_debug("blkid_verify: error %s (%d) while "
132 "opening %s", strerror(errno), errno,
133 dev->bid_name));
134 goto open_err;
135 }
136
137 if (blkid_probe_set_device(cache->probe, fd, 0, 0)) {
138 /* failed to read the device */
139 close(fd);
140 blkid_free_dev(dev);
141 return NULL;
142 }
143
144 /* remove old cache info */
145 iter = blkid_tag_iterate_begin(dev);
146 while (blkid_tag_next(iter, &type, &value) == 0)
147 blkid_set_tag(dev, type, NULL, 0);
148 blkid_tag_iterate_end(iter);
149
150 /* enable superblocks probing */
151 blkid_probe_enable_superblocks(cache->probe, TRUE);
152 blkid_probe_set_superblocks_flags(cache->probe,
153 BLKID_SUBLKS_LABEL | BLKID_SUBLKS_UUID |
154 BLKID_SUBLKS_TYPE | BLKID_SUBLKS_SECTYPE);
155
156 /* enable partitions probing */
157 blkid_probe_enable_partitions(cache->probe, TRUE);
158 blkid_probe_set_partitions_flags(cache->probe, BLKID_PARTS_ENTRY_DETAILS);
159
160 /* probe */
161 if (blkid_do_safeprobe(cache->probe)) {
162 /* found nothing or error */
163 blkid_free_dev(dev);
164 dev = NULL;
165 }
166
167 if (dev) {
168 #ifdef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
169 struct timeval tv;
170 if (!gettimeofday(&tv, NULL)) {
171 dev->bid_time = tv.tv_sec;
172 dev->bid_utime = tv.tv_usec;
173 } else
174 #endif
175 dev->bid_time = time(NULL);
176
177 dev->bid_devno = st.st_rdev;
178 dev->bid_flags |= BLKID_BID_FL_VERIFIED;
179 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
180
181 blkid_probe_to_tags(cache->probe, dev);
182
183 DBG(PROBE, ul_debug("%s: devno 0x%04llx, type %s",
184 dev->bid_name, (long long)st.st_rdev, dev->bid_type));
185 }
186
187 /* reset prober */
188 blkid_probe_reset_superblocks_filter(cache->probe);
189 blkid_probe_set_device(cache->probe, -1, 0, 0);
190 close(fd);
191
192 return dev;
193 }
194
195 #ifdef TEST_PROGRAM
196 int main(int argc, char **argv)
197 {
198 blkid_dev dev;
199 blkid_cache cache;
200 int ret;
201
202 if (argc != 2) {
203 fprintf(stderr, "Usage: %s device\n"
204 "Probe a single device to determine type\n", argv[0]);
205 exit(1);
206 }
207 if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
208 fprintf(stderr, "%s: error creating cache (%d)\n",
209 argv[0], ret);
210 exit(1);
211 }
212 dev = blkid_get_dev(cache, argv[1], BLKID_DEV_NORMAL);
213 if (!dev) {
214 printf("%s: %s has an unsupported type\n", argv[0], argv[1]);
215 return (1);
216 }
217 printf("TYPE='%s'\n", dev->bid_type ? dev->bid_type : "(null)");
218 if (dev->bid_label)
219 printf("LABEL='%s'\n", dev->bid_label);
220 if (dev->bid_uuid)
221 printf("UUID='%s'\n", dev->bid_uuid);
222
223 blkid_free_dev(dev);
224 return (0);
225 }
226 #endif