cgmanager: cgm_get: len = 0 is a query for length only

The caller might (like lxc-test-startone does) pass in a valid
(or invalid) buffer and 0 length.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/src/lxc/cgmanager.c b/src/lxc/cgmanager.c
index 8a5039a769658857cc8840ccd99209176297ab0c..1dea824b9eee1b84856c694ec336969f125abbf7 100644 (file)
--- a/src/lxc/cgmanager.c
+++ b/src/lxc/cgmanager.c
@@ -689,7 +689,7 @@ static int cgm_get(const char *filename, char *value, size_t len, const char *na
        cgm_dbus_disconnect();
        free(cgroup);
        newlen = strlen(result);
-       if (!value) {
+       if (!len || !value) {
                // user queries the size
                nih_free(result);
                return newlen+1;