140 lines
3.0 KiB
C
140 lines
3.0 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* resolve.c - resolve names and tags into specific devices
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*
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* Copyright (C) 2001, 2003 Theodore Ts'o.
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* Copyright (C) 2001 Andreas Dilger
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the
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* GNU Lesser General Public License.
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* %End-Header%
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*/
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#include <stdio.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <stdlib.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include "blkidP.h"
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#include "probe.h"
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/*
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* Find a tagname (e.g. LABEL or UUID) on a specific device.
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*/
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char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
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const char *devname)
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{
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blkid_tag found;
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blkid_dev dev;
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blkid_cache c = cache;
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char *ret = NULL;
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DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));
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if (!devname)
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return NULL;
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if (!cache) {
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if (blkid_get_cache(&c, NULL) < 0)
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return NULL;
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}
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if ((dev = blkid_get_dev(c, devname, BLKID_DEV_NORMAL)) &&
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(found = blkid_find_tag_dev(dev, tagname)))
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ret = blkid_strdup(found->bit_val);
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if (!cache)
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blkid_put_cache(c);
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return ret;
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}
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/*
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* Locate a device name from a token (NAME=value string), or (name, value)
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* pair. In the case of a token, value is ignored. If the "token" is not
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* of the form "NAME=value" and there is no value given, then it is assumed
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* to be the actual devname and a copy is returned.
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*/
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char *blkid_get_devname(blkid_cache cache, const char *token,
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const char *value)
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{
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blkid_dev dev;
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blkid_cache c = cache;
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char *t = NULL, *v = NULL;
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char *ret = NULL;
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if (!token)
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return NULL;
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if (!cache) {
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if (blkid_get_cache(&c, NULL) < 0)
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return NULL;
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}
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DBG(DEBUG_RESOLVE,
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printf("looking for %s%s%s %s\n", token, value ? "=" : "",
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value ? value : "", cache ? "in cache" : "from disk"));
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if (!value) {
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if (!strchr(token, '='))
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return blkid_strdup(token);
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blkid_parse_tag_string(token, &t, &v);
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if (!t || !v)
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goto errout;
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token = t;
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value = v;
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}
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dev = blkid_find_dev_with_tag(c, token, value);
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if (!dev)
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goto errout;
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ret = blkid_strdup(blkid_dev_devname(dev));
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errout:
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free(t);
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free(v);
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if (!cache) {
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blkid_put_cache(c);
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}
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return ret;
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}
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#ifdef TEST_PROGRAM
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int main(int argc, char **argv)
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{
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char *value;
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blkid_cache cache;
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blkid_debug_mask = DEBUG_ALL;
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if (argc != 2 && argc != 3) {
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fprintf(stderr, "Usage:\t%s tagname=value\n"
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"\t%s tagname devname\n"
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"Find which device holds a given token or\n"
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"Find what the value of a tag is in a device\n",
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argv[0], argv[0]);
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exit(1);
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}
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if (blkid_get_cache(&cache, bb_dev_null) < 0) {
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fprintf(stderr, "Can't get blkid cache\n");
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exit(1);
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}
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if (argv[2]) {
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value = blkid_get_tag_value(cache, argv[1], argv[2]);
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printf("%s has tag %s=%s\n", argv[2], argv[1],
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value ? value : "<missing>");
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} else {
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value = blkid_get_devname(cache, argv[1], NULL);
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printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
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}
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blkid_put_cache(cache);
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return value ? 0 : 1;
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}
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#endif
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