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/*
* Copyright (C) 2008 Karel Zak <kzak@redhat.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <sys/time.h>
#include <sys/types.h>
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include "blkidP.h"
static void blkid_probe_to_tags(blkid_probe pr, blkid_dev dev)
{
const char *data;
const char *name;
int nvals, n;
size_t len;
nvals = blkid_probe_numof_values(pr);
for (n = 0; n < nvals; n++) {
if (blkid_probe_get_value(pr, n, &name, &data, &len) != 0)
continue;
if (strncmp(name, "PART_ENTRY_", 11) == 0) {
if (strcmp(name, "PART_ENTRY_UUID") == 0)
blkid_set_tag(dev, "PARTUUID", data, len);
else if (strcmp(name, "PART_ENTRY_NAME") == 0)
blkid_set_tag(dev, "PARTLABEL", data, len);
} else if (!strstr(name, "_ID")) {
/* superblock UUID, LABEL, ...
* but not {SYSTEM,APPLICATION,..._ID} */
blkid_set_tag(dev, name, data, len);
}
}
}
/*
* Verify that the data in dev is consistent with what is on the actual
* block device (using the devname field only). Normally this will be
* called when finding items in the cache, but for long running processes
* is also desirable to revalidate an item before use.
*
* If we are unable to revalidate the data, we return the old data and
* do not set the BLKID_BID_FL_VERIFIED flag on it.
*/
blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
{
blkid_tag_iterate iter;
const char *type, *value;
struct stat st;
time_t diff, now;
int fd;
if (!dev || !cache)
return NULL;
now = time(0);
diff = now - dev->bid_time;
if (stat(dev->bid_name, &st) < 0) {
DBG(DEBUG_PROBE,
printf("blkid_verify: error %m (%d) while "
"trying to stat %s\n", errno,
dev->bid_name));
open_err:
if ((errno == EPERM) || (errno == EACCES) || (errno == ENOENT)) {
/* We don't have read permission, just return cache data. */
DBG(DEBUG_PROBE, printf("returning unverified data for %s\n",
dev->bid_name));
return dev;
}
blkid_free_dev(dev);
return NULL;
}
if (now >= dev->bid_time &&
#ifdef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
(st.st_mtime < dev->bid_time ||
(st.st_mtime == dev->bid_time &&
st.st_mtim.tv_nsec / 1000 <= dev->bid_utime)) &&
#else
st.st_mtime <= dev->bid_time &&
#endif
(diff < BLKID_PROBE_MIN ||
(dev->bid_flags & BLKID_BID_FL_VERIFIED &&
diff < BLKID_PROBE_INTERVAL)))
return dev;
#ifndef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
DBG(DEBUG_PROBE,
printf("need to revalidate %s (cache time %lu, stat time %lu,\n\t"
"time since last check %lu)\n",
dev->bid_name, (unsigned long)dev->bid_time,
(unsigned long)st.st_mtime, (unsigned long)diff));
#else
DBG(DEBUG_PROBE,
printf("need to revalidate %s (cache time %lu.%lu, stat time %lu.%lu,\n\t"
"time since last check %lu)\n",
dev->bid_name,
(unsigned long)dev->bid_time, (unsigned long)dev->bid_utime,
(unsigned long)st.st_mtime, (unsigned long)st.st_mtim.tv_nsec / 1000,
(unsigned long)diff));
#endif
if (!cache->probe) {
cache->probe = blkid_new_probe();
if (!cache->probe) {
blkid_free_dev(dev);
return NULL;
}
}
fd = open(dev->bid_name, O_RDONLY|O_CLOEXEC);
if (fd < 0) {
DBG(DEBUG_PROBE, printf("blkid_verify: error %m (%d) while "
"opening %s\n", errno,
dev->bid_name));
goto open_err;
}
if (blkid_probe_set_device(cache->probe, fd, 0, 0)) {
/* failed to read the device */
close(fd);
blkid_free_dev(dev);
return NULL;
}
/* remove old cache info */
iter = blkid_tag_iterate_begin(dev);
while (blkid_tag_next(iter, &type, &value) == 0)
blkid_set_tag(dev, type, NULL, 0);
blkid_tag_iterate_end(iter);
/* enable superblocks probing */
blkid_probe_enable_superblocks(cache->probe, TRUE);
blkid_probe_set_superblocks_flags(cache->probe,
BLKID_SUBLKS_LABEL | BLKID_SUBLKS_UUID |
BLKID_SUBLKS_TYPE | BLKID_SUBLKS_SECTYPE);
/* enable partitions probing */
blkid_probe_enable_partitions(cache->probe, TRUE);
blkid_probe_set_partitions_flags(cache->probe, BLKID_PARTS_ENTRY_DETAILS);
/* probe */
if (blkid_do_safeprobe(cache->probe)) {
/* found nothing or error */
blkid_free_dev(dev);
dev = NULL;
}
if (dev) {
#ifdef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
struct timeval tv;
if (!gettimeofday(&tv, NULL)) {
dev->bid_time = tv.tv_sec;
dev->bid_utime = tv.tv_usec;
} else
#endif
dev->bid_time = time(0);
dev->bid_devno = st.st_rdev;
dev->bid_flags |= BLKID_BID_FL_VERIFIED;
cache->bic_flags |= BLKID_BIC_FL_CHANGED;
blkid_probe_to_tags(cache->probe, dev);
DBG(DEBUG_PROBE, printf("%s: devno 0x%04llx, type %s\n",
dev->bid_name, (long long)st.st_rdev, dev->bid_type));
}
blkid_reset_probe(cache->probe);
blkid_probe_reset_superblocks_filter(cache->probe);
close(fd);
return dev;
}
#ifdef TEST_PROGRAM
int main(int argc, char **argv)
{
blkid_dev dev;
blkid_cache cache;
int ret;
if (argc != 2) {
fprintf(stderr, "Usage: %s device\n"
"Probe a single device to determine type\n", argv[0]);
exit(1);
}
if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
fprintf(stderr, "%s: error creating cache (%d)\n",
argv[0], ret);
exit(1);
}
dev = blkid_get_dev(cache, argv[1], BLKID_DEV_NORMAL);
if (!dev) {
printf("%s: %s has an unsupported type\n", argv[0], argv[1]);
return (1);
}
printf("TYPE='%s'\n", dev->bid_type ? dev->bid_type : "(null)");
if (dev->bid_label)
printf("LABEL='%s'\n", dev->bid_label);
if (dev->bid_uuid)
printf("UUID='%s'\n", dev->bid_uuid);
blkid_free_dev(dev);
return (0);
}
#endif
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