nss/libsubid: simplify the ranges variable for list_owner_ranges

Following alexey-tikhonov's suggestion.

Since we've dropped the 'owner' field in the data returned for
get_subid_ranges, we can just return a single allocated array of
simple structs.  This means we can return a ** instead of ***, and
we can get rid of the subid_free_ranges() helper, since the caller
can just free() the returned data.

Signed-off-by: Serge Hallyn <serge@hallyn.com>

lib/prototypes.h

@@ -300,16 +300,15 @@ struct subid_nss_ops {
 	 *
 	 * @owner - string representing username being queried
 	 * @id_type - subuid or subgid
-	 * @ranges - pointer to an array of struct subid_range pointers, or
-	 *           NULL.  The returned array of struct subid_range and its
-	 *           members must be freed by the caller.
+	 * @ranges - pointer to an array of struct subid_range, or NULL.  The
+	 *           returned array must be freed by the caller.
 	 * @count - pointer to an integer into which the number of returned ranges
 	 *          is written.
 
 	 * returns success if the module was able to determine an answer,
 	 * else an error status.
 	 */
-	enum subid_status (*list_owner_ranges)(const char *owner, enum subid_type id_type, struct subid_range ***ranges, int *count);
+	enum subid_status (*list_owner_ranges)(const char *owner, enum subid_type id_type, struct subid_range **ranges, int *count);
 
 	/*
 	 * nss_find_subid_owners: find uids who own a given subuid or subgid.

lib/subordinateio.c

@@ -17,23 +17,6 @@
 #include <ctype.h>
 #include <fcntl.h>
 
-/* subid_free_ranges: free a subid_range
- *
- * @ranges: an array of subid_ranges to free
- * @count: number of items in the array
- *
- * The subid_range is a subordinate_range without the owner field,
- * defined in subid.h
- */
-void subid_free_ranges(struct subid_range **ranges, int count)
-{
-	int i;
-
-	for (i = 0; i < count; i++)
-		free(ranges[i]);
-	free(ranges);
-}
-
 /*
  * subordinate_dup: create a duplicate range
  *
@@ -326,26 +309,21 @@ static bool have_range(struct commonio_db *db,
 	return false;
 }
 
-static bool append_range(struct subid_range ***ranges, const struct subordinate_range *new, int n)
+static bool append_range(struct subid_range **ranges, const struct subordinate_range *new, int n)
 {
-	struct subid_range *tmp;
 	if (!*ranges) {
-		*ranges = malloc(sizeof(struct subid_range *));
+		*ranges = malloc(sizeof(struct subid_range));
 		if (!*ranges)
 			return false;
 	} else {
-		struct subid_range **new;
-		new = realloc(*ranges, (n + 1) * (sizeof(struct subid_range *)));
-		if (!new)
+		struct subid_range *alloced;
+		alloced = realloc(*ranges, (n + 1) * (sizeof(struct subid_range)));
+		if (!alloced)
 			return false;
-		*ranges = new;
+		*ranges = alloced;
 	}
-	(*ranges)[n] = NULL;
-	tmp = malloc(sizeof(*tmp));
-	if (!tmp)
-		return false;
-	memcpy(tmp, new, sizeof(*tmp));
-	(*ranges)[n] = tmp;
+	(*ranges)[n].start = new->start;
+	(*ranges)[n].count = new->count;
 	return true;
 }
 
@@ -804,10 +782,10 @@ gid_t sub_gid_find_free_range(gid_t min, gid_t max, unsigned long count)
  *
  * The caller must free the subordinate range list.
  */
-int list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_range ***in_ranges)
+int list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_range **in_ranges)
 {
 	// TODO - need to handle owner being either uid or username
-	struct subid_range **ranges = NULL;
+	struct subid_range *ranges = NULL;
 	const struct subordinate_range *range;
 	struct commonio_db *db;
 	enum subid_status status;
@@ -845,7 +823,7 @@ int list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_r
 	while ((range = commonio_next(db)) != NULL) {
 		if (0 == strcmp(range->owner, owner)) {
 			if (!append_range(&ranges, range, count++)) {
-				subid_free_ranges(ranges, count-1);
+				free(ranges);
 				ranges = NULL;
 				count = -1;
 				goto out;

lib/subordinateio.h

@@ -25,7 +25,7 @@ extern int sub_uid_unlock (void);
 extern int sub_uid_add (const char *owner, uid_t start, unsigned long count);
 extern int sub_uid_remove (const char *owner, uid_t start, unsigned long count);
 extern uid_t sub_uid_find_free_range(uid_t min, uid_t max, unsigned long count);
-extern int list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_range ***ranges);
+extern int list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_range **ranges);
 extern bool new_subid_range(struct subordinate_range *range, enum subid_type id_type, bool reuse);
 extern bool release_subid_range(struct subordinate_range *range, enum subid_type id_type);
 extern int find_subid_owners(unsigned long id, enum subid_type id_type, uid_t **uids);