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