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-rw-r--r--libblkid/resolve.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/libblkid/resolve.c b/libblkid/resolve.c
new file mode 100644
index 000000000..96749b3ec
--- /dev/null
+++ b/libblkid/resolve.c
@@ -0,0 +1,131 @@
+/*
+ * resolve.c - resolve names and tags into specific devices
+ *
+ * Copyright (C) 2001, 2003 Theodore Ts'o.
+ * Copyright (C) 2001 Andreas Dilger
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "blkidP.h"
+
+/*
+ * Find a tagname (e.g. LABEL or UUID) on a specific device.
+ */
+char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
+ const char *devname)
+{
+ blkid_tag found;
+ blkid_dev dev;
+ blkid_cache c = cache;
+ char *ret = NULL;
+
+ DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));
+
+ if (!devname)
+ return NULL;
+ if (!cache && blkid_get_cache(&c, NULL) < 0)
+ return NULL;
+
+ if ((dev = blkid_get_dev(c, devname, BLKID_DEV_NORMAL)) &&
+ (found = blkid_find_tag_dev(dev, tagname)))
+ ret = found->bit_val ? strdup(found->bit_val) : NULL;
+
+ if (!cache)
+ blkid_put_cache(c);
+
+ return ret;
+}
+
+/*
+ * Locate a device name from a token (NAME=value string), or (name, value)
+ * pair. In the case of a token, value is ignored. If the "token" is not
+ * of the form "NAME=value" and there is no value given, then it is assumed
+ * to be the actual devname and a copy is returned.
+ */
+char *blkid_get_devname(blkid_cache cache, const char *token,
+ const char *value)
+{
+ blkid_dev dev;
+ blkid_cache c = cache;
+ char *t = 0, *v = 0;
+ char *ret = NULL;
+
+ if (!token)
+ return NULL;
+ if (!cache && blkid_get_cache(&c, NULL) < 0)
+ return NULL;
+
+ DBG(DEBUG_RESOLVE,
+ printf("looking for %s%s%s %s\n", token, value ? "=" : "",
+ value ? value : "", cache ? "in cache" : "from disk"));
+
+ if (!value) {
+ if (!strchr(token, '=')) {
+ ret = strdup(token);
+ goto out;
+ }
+ blkid_parse_tag_string(token, &t, &v);
+ if (!t || !v)
+ goto out;
+ token = t;
+ value = v;
+ }
+
+ dev = blkid_find_dev_with_tag(c, token, value);
+ if (!dev)
+ goto out;
+
+ ret = dev->bid_name ? strdup(dev->bid_name) : NULL;
+out:
+ free(t);
+ free(v);
+ if (!cache)
+ blkid_put_cache(c);
+ return ret;
+}
+
+#ifdef TEST_PROGRAM
+int main(int argc, char **argv)
+{
+ char *value;
+ blkid_cache cache;
+
+ blkid_init_debug(DEBUG_ALL);
+ if (argc != 2 && argc != 3) {
+ fprintf(stderr, "Usage:\t%s tagname=value\n"
+ "\t%s tagname devname\n"
+ "Find which device holds a given token or\n"
+ "Find what the value of a tag is in a device\n",
+ argv[0], argv[0]);
+ exit(1);
+ }
+ if (blkid_get_cache(&cache, "/dev/null") < 0) {
+ fprintf(stderr, "Couldn't get blkid cache\n");
+ exit(1);
+ }
+
+ if (argv[2]) {
+ value = blkid_get_tag_value(cache, argv[1], argv[2]);
+ printf("%s has tag %s=%s\n", argv[2], argv[1],
+ value ? value : "<missing>");
+ } else {
+ value = blkid_get_devname(cache, argv[1], NULL);
+ printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
+ }
+ blkid_put_cache(cache);
+ return value ? 0 : 1;
+}
+#endif