1 files changed, 60 insertions, 29 deletions

diff --git a/libmount/src/cache.c b/libmount/src/cache.c
index 7b651228a..92f469456 100644
--- a/libmount/src/cache.c
+++ b/libmount/src/cache.c
@@ -10,7 +10,7 @@
  * @title: Cache
  * @short_description: paths and tags (UUID/LABEL) caching
  *
- * The cache is a very simple API for work with tags (LABEL, UUID, ...) and
+ * The cache is a very simple API for working with tags (LABEL, UUID, ...) and
  * paths. The cache uses libblkid as a backend for TAGs resolution.
  *
  * All returned paths are always canonicalized.
@@ -48,6 +48,7 @@ struct libmnt_cache {
 	struct mnt_cache_entry	*ents;
 	size_t			nents;
 	size_t			nallocs;
+	int			refcount;
 
 	/* blkid_evaluate_tag() works in two ways:
 	 *
@@ -72,6 +73,7 @@ struct libmnt_cache *mnt_new_cache(void)
 	if (!cache)
 		return NULL;
 	DBG(CACHE, mnt_debug_h(cache, "alloc"));
+	cache->refcount = 1;
 	return cache;
 }
 
@@ -79,7 +81,8 @@ struct libmnt_cache *mnt_new_cache(void)
  * mnt_free_cache:
  * @cache: pointer to struct libmnt_cache instance
  *
- * Deallocates the cache.
+ * Deallocates the cache. This function does not care about reference count. Don't
+ * use this function directly -- it's better to use use mnt_unref_cache().
  */
 void mnt_free_cache(struct libmnt_cache *cache)
 {
@@ -89,6 +92,7 @@ void mnt_free_cache(struct libmnt_cache *cache)
 		return;
 
 	DBG(CACHE, mnt_debug_h(cache, "free"));
+	WARN_REFCOUNT(CACHE, cache, cache->refcount);
 
 	for (i = 0; i < cache->nents; i++) {
 		struct mnt_cache_entry *e = &cache->ents[i];
@@ -102,7 +106,39 @@ void mnt_free_cache(struct libmnt_cache *cache)
 	free(cache);
 }
 
-/* note that the @key could be tha same pointer as @value */
+/**
+ * mnt_ref_cache:
+ * @cache: cache pointer
+ *
+ * Increments reference counter.
+ */
+void mnt_ref_cache(struct libmnt_cache *cache)
+{
+	if (cache) {
+		cache->refcount++;
+		/*DBG(CACHE, mnt_debug_h(cache, "ref=%d", cache->refcount));*/
+	}
+}
+
+/**
+ * mnt_unref_cache:
+ * @cache: cache pointer
+ *
+ * De-increments reference counter, on zero the cache is automatically
+ * deallocated by mnt_free_cache().
+ */
+void mnt_unref_cache(struct libmnt_cache *cache)
+{
+	if (cache) {
+		cache->refcount--;
+		/*DBG(CACHE, mnt_debug_h(cache, "unref=%d", cache->refcount));*/
+		if (cache->refcount <= 0)
+			mnt_free_cache(cache);
+	}
+}
+
+
+/* note that the @key could be the same pointer as @value */
 static int cache_add_entry(struct libmnt_cache *cache, char *key,
 					char *value, int flag)
 {
@@ -135,7 +171,7 @@ static int cache_add_entry(struct libmnt_cache *cache, char *key,
 	return 0;
 }
 
-/* add tag to the cache, @devname has to be allocated string */
+/* add tag to the cache, @devname has to be an allocated string */
 static int cache_add_tag(struct libmnt_cache *cache, const char *tagname,
 				const char *tagval, char *devname, int flag)
 {
@@ -270,13 +306,13 @@ int mnt_cache_read_tags(struct libmnt_cache *cache, const char *devname)
 
 	DBG(CACHE, mnt_debug_h(cache, "tags for %s requested", devname));
 
-	/* check is device is already cached */
+	/* check if device is already cached */
 	for (i = 0; i < cache->nents; i++) {
 		struct mnt_cache_entry *e = &cache->ents[i];
 		if (!(e->flag & MNT_CACHE_TAGREAD))
 			continue;
 		if (strcmp(e->value, devname) == 0)
-			/* tags has been already read */
+			/* tags have already been read */
 			return 0;
 	}
 
@@ -335,7 +371,7 @@ error:
  * @token: tag name (e.g "LABEL")
  * @value: tag value
  *
- * Look up @cache to check it @tag+@value are associated with @devname.
+ * Look up @cache to check if @tag+@value are associated with @devname.
  *
  * Returns: 1 on success or 0.
  */
@@ -421,7 +457,7 @@ char *mnt_get_fstype(const char *devname, int *ambi, struct libmnt_cache *cache)
 
 	rc = blkid_do_safeprobe(pr);
 
-	DBG(CACHE, mnt_debug_h(cache, "liblkid rc=%d", rc));
+	DBG(CACHE, mnt_debug_h(cache, "libblkid rc=%d", rc));
 
 	if (!rc && !blkid_probe_lookup_value(pr, "TYPE", &data, NULL))
 		type = strdup(data);
@@ -493,7 +529,7 @@ error:
  *	- /dev/loopN to the loop backing filename
  *	- empty path (NULL) to 'none'
  *
- * Returns: new allocated string with path, result has to be always deallocated
+ * Returns: newly allocated string with path, result always has to be deallocated
  *          by free().
  */
 char *mnt_pretty_path(const char *path, struct libmnt_cache *cache)
@@ -583,22 +619,18 @@ error:
 char *mnt_resolve_spec(const char *spec, struct libmnt_cache *cache)
 {
 	char *cn = NULL;
+	char *t = NULL, *v = NULL;
 
 	if (!spec)
 		return NULL;
 
-	if (strchr(spec, '=')) {
-		char *tag, *val;
-
-		if (!blkid_parse_tag_string(spec, &tag, &val)) {
-			cn = mnt_resolve_tag(tag, val, cache);
-
-			free(tag);
-			free(val);
-		}
-	} else
+	if (blkid_parse_tag_string(spec, &t, &v) == 0 && mnt_valid_tagname(t))
+		cn = mnt_resolve_tag(t, v, cache);
+	else
 		cn = mnt_resolve_path(spec, cache);
 
+	free(t);
+	free(v);
 	return cn;
 }
 
@@ -624,7 +656,7 @@ int test_resolve_path(struct libmnt_test *ts, int argc, char *argv[])
 		p = mnt_resolve_path(line, cache);
 		printf("%s : %s\n", line, p);
 	}
-	mnt_free_cache(cache);
+	mnt_unref_cache(cache);
 	return 0;
 }
 
@@ -647,7 +679,7 @@ int test_resolve_spec(struct libmnt_test *ts, int argc, char *argv[])
 		p = mnt_resolve_spec(line, cache);
 		printf("%s : %s\n", line, p);
 	}
-	mnt_free_cache(cache);
+	mnt_unref_cache(cache);
 	return 0;
 }
 
@@ -663,6 +695,7 @@ int test_read_tags(struct libmnt_test *ts, int argc, char *argv[])
 
 	while(fgets(line, sizeof(line), stdin)) {
 		size_t sz = strlen(line);
+		char *t = NULL, *v = NULL;
 
 		if (sz > 0 && line[sz - 1] == '\n')
 			line[sz - 1] = '\0';
@@ -674,16 +707,14 @@ int test_read_tags(struct libmnt_test *ts, int argc, char *argv[])
 			if (mnt_cache_read_tags(cache, line) < 0)
 				fprintf(stderr, "%s: read tags failed\n", line);
 
-		} else if (strchr(line, '=')) {
-			char *tag, *val;
+		} else if (blkid_parse_tag_string(line, &t, &v) == 0) {
 			const char *cn = NULL;
 
-			if (!blkid_parse_tag_string(line, &tag, &val)) {
-				cn = cache_find_tag(cache, tag, val);
+			if (mnt_valid_tagname(t))
+				cn = cache_find_tag(cache, t, v);
+			free(t);
+			free(v);
 
-				free(tag);
-				free(val);
-			}
 			if (cn)
 				printf("%s: %s\n", line, cn);
 			else
@@ -700,7 +731,7 @@ int test_read_tags(struct libmnt_test *ts, int argc, char *argv[])
 				e->key + strlen(e->key) + 1);
 	}
 
-	mnt_free_cache(cache);
+	mnt_unref_cache(cache);
 	return 0;
 
 }