[lxc-devel] [PATCH 1/1] lxc_global_config_value: simplify the theme

[Serge Hallyn]

Rather than try to free all the not-being-returned items at
each if clause where we assign one to return value, just NULL
the one we are returning so we can safely free all the
values.  This should fix the newly reported coverity memory
leak

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
---
 src/lxc/utils.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index b572982..34743dd 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -277,7 +277,14 @@ const char *lxc_global_config_value(const char *option_name)
 #else
 	static const char *values[sizeof(options) / sizeof(options[0])] = { 0 };
 #endif
+
+	/* user_config_path is freed as soon as it is used */
 	char *user_config_path = NULL;
+
+	/*
+	 * The following variables are freed at bottom unconditionally.
+	 * So NULL the value if it is to be returned to the caller
+	 */
 	char *user_default_config_path = NULL;
 	char *user_lxc_path = NULL;
 	char *user_cgroup_pattern = NULL;
@@ -364,8 +371,6 @@ const char *lxc_global_config_value(const char *option_name)
 			if (!*p)
 				continue;
 
-			free(user_default_config_path);
-
 			if (strcmp(option_name, "lxc.lxcpath") == 0) {
 				free(user_lxc_path);
 				user_lxc_path = copy_global_config_value(p);
@@ -375,7 +380,6 @@ const char *lxc_global_config_value(const char *option_name)
 			}
 
 			values[i] = copy_global_config_value(p);
-			free(user_lxc_path);
 			goto out;
 		}
 	}
@@ -383,25 +387,19 @@ const char *lxc_global_config_value(const char *option_name)
 	if (strcmp(option_name, "lxc.lxcpath") == 0) {
 		remove_trailing_slashes(user_lxc_path);
 		values[i] = user_lxc_path;
-		free(user_default_config_path);
-		free(user_cgroup_pattern);
+		user_lxc_path = NULL;
 	}
 	else if (strcmp(option_name, "lxc.default_config") == 0) {
 		values[i] = user_default_config_path;
-		free(user_lxc_path);
-		free(user_cgroup_pattern);
+		user_default_config_path = NULL;
 	}
 	else if (strcmp(option_name, "lxc.cgroup.pattern") == 0) {
 		values[i] = user_cgroup_pattern;
-		free(user_default_config_path);
-		free(user_lxc_path);
+		user_cgroup_pattern = NULL;
 	}
-	else {
-		free(user_default_config_path);
-		free(user_lxc_path);
-		free(user_cgroup_pattern);
+	else
 		values[i] = (*ptr)[1];
-	}
+
 	/* special case: if default value is NULL,
 	 * and there is no config, don't view that
 	 * as an error... */
@@ -412,6 +410,10 @@ out:
 	if (fin)
 		fclose(fin);
 
+	free(user_cgroup_pattern);
+	free(user_default_config_path);
+	free(user_lxc_path);
+
 	return values[i];
 }
 
-- 
2.1.0