utils: rework lxc_setgroups()

src/lxc/utils.c

@@ -1454,14 +1454,20 @@ bool lxc_drop_groups(void)
 	return ret == 0;
 }
 
-bool lxc_setgroups(int size, gid_t list[])
+bool lxc_setgroups(gid_t list[], size_t size)
 {
-	if (setgroups(size, list) < 0) {
-		SYSERROR("Failed to setgroups()");
-		return false;
+	int ret;
+
+	ret = setgroups(size, list);
+	if (ret)
+		return log_error_errno(false, errno, "Failed to set supplimentary groups");
+
+	if (size > 0 && lxc_log_trace()) {
+		for (size_t i = 0; i < size; i++)
+			TRACE("Setting supplimentary group %d", list[i]);
 	}
-	NOTICE("Dropped additional groups");
 
+	NOTICE("Set supplimentary groups");
 	return true;
 }
 

src/lxc/utils.h

@@ -156,7 +156,7 @@ __hidden extern bool task_blocks_signal(pid_t pid, int signal);
  * If LXC_INVALID_{G,U}ID is passed then the set{g,u}id() will not be called.
  */
 __hidden extern bool lxc_switch_uid_gid(uid_t uid, gid_t gid);
-__hidden extern bool lxc_setgroups(int size, gid_t list[]);
+__hidden extern bool lxc_setgroups(gid_t list[], size_t size);
 __hidden extern bool lxc_drop_groups(void);
 
 /* Find an unused loop device and associate it with source. */