cgfsng: fail when limits fail to apply

So far, we silently skipped over limits that failed to be applied which is very
odd. Let's error on when cgroup limits fail to apply.

Closes #1815.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index fe3fd7062a442fe72e3166011aad6f1dd5595481..ed391a616ac046aeca2ca6474164d99b98179b58 100644 (file)
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -2009,15 +2009,16 @@ out:
  */
 static int lxc_cgroup_set_data(const char *filename, const char *value, struct cgfsng_handler_data *d)
 {
-       char *subsystem = NULL, *p;
-       int ret = 0;
-       struct hierarchy *h;
+       char *fullpath, *p;
        /* "b|c <2^64-1>:<2^64-1> r|w|m" = 47 chars max */
        char converted_value[50];
+       struct hierarchy *h;
+       int ret = 0;
+       char *controller = NULL;
 
-       subsystem = alloca(strlen(filename) + 1);
-       strcpy(subsystem, filename);
-       if ((p = strchr(subsystem, '.')) != NULL)
+       controller = alloca(strlen(filename) + 1);
+       strcpy(controller, filename);
+       if ((p = strchr(controller, '.')) != NULL)
                *p = '\0';
 
        if (strcmp("devices.allow", filename) == 0 && value[0] == '/') {
@@ -2028,12 +2029,18 @@ static int lxc_cgroup_set_data(const char *filename, const char *value, struct c
 
        }
 
-       h = get_hierarchy(subsystem);
-       if (h) {
-               char *fullpath = must_make_path(h->fullcgpath, filename, NULL);
-               ret = lxc_write_to_file(fullpath, value, strlen(value), false);
-               free(fullpath);
+       h = get_hierarchy(controller);
+       if (!h) {
+               ERROR("Failed to setup limits for the \"%s\" controller. "
+                     "The controller seems to be unused by \"cgfsng\" cgroup "
+                     "driver or not enabled on the cgroup hierarchy",
+                     controller);
+               return -1;
        }
+
+       fullpath = must_make_path(h->fullcgpath, filename, NULL);
+       ret = lxc_write_to_file(fullpath, value, strlen(value), false);
+       free(fullpath);
        return ret;
 }