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 <[email protected]>
shadow-maint · May 22, 2021 · 3d670ba · 3d670ba
1 parent 322db32
commit 3d670ba
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Showing 8 changed files with 39 additions and 74 deletions.
diff --git a/configure.ac b/configure.ac
@@ -1,6 +1,6 @@
 dnl Process this file with autoconf to produce a configure script.
 AC_PREREQ([2.69])
-m4_define([libsubid_abi_major], 2)
+m4_define([libsubid_abi_major], 3)
 m4_define([libsubid_abi_minor], 0)
 m4_define([libsubid_abi_micro], 0)
 m4_define([libsubid_abi], [libsubid_abi_major.libsubid_abi_minor.libsubid_abi_micro])

diff --git a/lib/prototypes.h b/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.

diff --git a/lib/subordinateio.c b/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;

diff --git a/lib/subordinateio.h b/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);

diff --git a/libsubid/api.c b/libsubid/api.c
@@ -66,17 +66,17 @@ bool libsubid_init(const char *progname, FILE * logfd)
 }
 
 static
-int get_subid_ranges(const char *owner, enum subid_type id_type, struct subid_range ***ranges)
+int get_subid_ranges(const char *owner, enum subid_type id_type, struct subid_range **ranges)
 {
 	return list_owner_ranges(owner, id_type, ranges);
 }
 
-int get_subuid_ranges(const char *owner, struct subid_range ***ranges)
+int get_subuid_ranges(const char *owner, struct subid_range **ranges)
 {
 	return get_subid_ranges(owner, ID_TYPE_UID, ranges);
 }
 
-int get_subgid_ranges(const char *owner, struct subid_range ***ranges)
+int get_subgid_ranges(const char *owner, struct subid_range **ranges)
 {
 	return get_subid_ranges(owner, ID_TYPE_GID, ranges);
 }

diff --git a/libsubid/subid.h b/libsubid/subid.h
@@ -50,32 +50,27 @@ bool libsubid_init(const char *progname, FILE *logfd);
  * get_subuid_ranges: return a list of UID ranges for a user
  *
  * @owner: username being queried
- * @ranges: a pointer to a subordinate range ** in which the result will be
- *          returned.
+ * @ranges: a pointer to an array of subid_range structs in which the result
+ *          will be returned.
+ *
+ * The caller must free(ranges) when done.
  *
  * returns: number of ranges found, ir < 0 on error.
  */
-int get_subuid_ranges(const char *owner, struct subid_range ***ranges);
+int get_subuid_ranges(const char *owner, struct subid_range **ranges);
 
 /*
  * get_subgid_ranges: return a list of GID ranges for a user
  *
  * @owner: username being queried
- * @ranges: a pointer to a subordinate range ** in which the result will be
- *          returned.
+ * @ranges: a pointer to an array of subid_range structs in which the result
+ *          will be returned.
  *
- * returns: number of ranges found, ir < 0 on error.
- */
-int get_subgid_ranges(const char *owner, struct subid_range ***ranges);
-
-/*
- * subid_free_ranges: free an array of subordinate_ranges returned by either
- *                    get_subuid_ranges() or get_subgid_ranges().
+ * The caller must free(ranges) when done.
  *
- * @ranges: the ranges to free
- * @count: the number of ranges in @ranges
+ * returns: number of ranges found, ir < 0 on error.
  */
-void subid_free_ranges(struct subid_range **ranges, int count);
+int get_subgid_ranges(const char *owner, struct subid_range **ranges);
 
 /*
  * get_subuid_owners: return a list of uids to which the given uid has been

diff --git a/src/list_subid_ranges.c b/src/list_subid_ranges.c
@@ -17,7 +17,7 @@ void usage(void)
 int main(int argc, char *argv[])
 {
 	int i, count=0;
-	struct subid_range **ranges;
+	struct subid_range *ranges;
 	const char *owner;
 
 	Prog = Basename (argv[0]);
@@ -39,8 +39,7 @@ int main(int argc, char *argv[])
 	}
 	for (i = 0; i < count; i++) {
 		printf("%d: %s %lu %lu\n", i, owner,
-			ranges[i]->start, ranges[i]->count);
+			ranges[i].start, ranges[i].count);
 	}
-	subid_free_ranges(ranges, count);
 	return 0;
 }
diff --git a/tests/libsubid/04_nss/libsubid_zzz.c b/tests/libsubid/04_nss/libsubid_zzz.c
@@ -101,9 +101,9 @@ enum subid_status shadow_subid_find_subid_owners(unsigned long id, enum subid_ty
 	return SUBID_STATUS_SUCCESS;
 }
 
-enum subid_status shadow_subid_list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_range ***in_ranges, int *count)
+enum subid_status shadow_subid_list_owner_ranges(const char *owner, enum subid_type id_type, struct subid_range **in_ranges, int *count)
 {
-	struct subid_range **ranges;
+	struct subid_range *ranges;
 
 	*count = 0;
 	if (strcmp(owner, "error") == 0)
@@ -113,29 +113,23 @@ enum subid_status shadow_subid_list_owner_ranges(const char *owner, enum subid_t
 	if (strcmp(owner, "conn") == 0)
 		return SUBID_STATUS_ERROR_CONN;
 
-	*ranges = NULL;
+	*in_ranges = NULL;
 	if (strcmp(owner, "user1") != 0 && strcmp(owner, "ubuntu") != 0 &&
 	    strcmp(owner, "group1") != 0)
 		return SUBID_STATUS_SUCCESS;
 	if (id_type == ID_TYPE_GID && strcmp(owner, "user1") == 0)
 		return SUBID_STATUS_SUCCESS;
 	if (id_type == ID_TYPE_UID && strcmp(owner, "group1") == 0)
 		return SUBID_STATUS_SUCCESS;
-	ranges = (struct subid_range **)malloc(sizeof(struct subid_range *));
+	ranges = (struct subid_range *)malloc(sizeof(struct subid_range));
 	if (!*ranges)
 		return SUBID_STATUS_ERROR;
-	ranges[0] = (struct subid_range *)malloc(sizeof(struct subid_range));
-	if (!ranges[0]) {
-		free(*ranges);
-		*ranges = NULL;
-		return SUBID_STATUS_ERROR;
-	}
 	if (strcmp(owner, "user1") == 0 || strcmp(owner, "group1") == 0) {
-		ranges[0]->start = 100000;
-		ranges[0]->count = 65536;
+		ranges[0].start = 100000;
+		ranges[0].count = 65536;
 	} else {
-		ranges[0]->start = 200000;
-		ranges[0]->count = 100000;
+		ranges[0].start = 200000;
+		ranges[0].count = 100000;
 	}
 
 	*count = 1;