+static int check(const char *p) {
+ char *cc;
+
+ assert(p);
+
+ /* Check if this controller actually really exists */
+ cc = alloca(sizeof("/sys/fs/cgroup/") + strlen(p));
+ strcpy(stpcpy(cc, "/sys/fs/cgroup/"), p);
+ if (access(cc, F_OK) < 0)
+ return -errno;
+
+ return 0;
+}
+