cgmanager: also handle named subsystems (like name=systemd)

Read /proc/self/cgroup instead of /proc/cgroups, so as to catch
named subsystems.  Otherwise the contaienrs will not be fully
moved into the container cgroups.

Also free line which was being leaked.

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 fc959ec0302fe44bead150d2c2b95eb7829e4b61..ab061e4d8ffd211b269156063f8b617394892c34 100644 (file)
--- a/src/lxc/cgmanager.c
+++ b/src/lxc/cgmanager.c
@@ -758,39 +758,53 @@ static void free_subsystems(void)
 
 static bool collect_subsytems(void)
 {
-       char *line = NULL, *tab1;
+       char *line = NULL;
        size_t sz = 0;
        FILE *f;
 
        if (subsystems) // already initialized
                return true;
 
-       f = fopen_cloexec("/proc/cgroups", "r");
+       f = fopen_cloexec("/proc/self/cgroup", "r");
        if (!f) {
-               return false;
+               f = fopen_cloexec("/proc/1/cgroup", "r");
+               if (!f)
+                       return false;
        }
        while (getline(&line, &sz, f) != -1) {
-               char **tmp;
-               if (line[0] == '#')
-                       continue;
+               /* file format: hierarchy:subsystems:group,
+                * with multiple subsystems being ,-separated */
+               char *slist, *end, *p, *saveptr = NULL, **tmp;
+
                if (!line[0])
                        continue;
-               tab1 = strchr(line, '\t');
-               if (!tab1)
+
+               slist = strchr(line, ':');
+               if (!slist)
+                       continue;
+               slist++;
+               end = strchr(slist, ':');
+               if (!end)
                        continue;
-               *tab1 = '\0';
-               tmp = realloc(subsystems, (nr_subsystems+1)*sizeof(char *));
-               if (!tmp)
-                       goto out_free;
-
-               subsystems = tmp;
-               tmp[nr_subsystems] = strdup(line);
-               if (!tmp[nr_subsystems])
-                       goto out_free;
-               nr_subsystems++;
+               *end = '\0';
+
+               for (p = strtok_r(slist, ",", &saveptr);
+                               p;
+                               p = strtok_r(NULL, ",", &saveptr)) {
+                       tmp = realloc(subsystems, (nr_subsystems+1)*sizeof(char *));
+                       if (!tmp)
+                               goto out_free;
+
+                       subsystems = tmp;
+                       tmp[nr_subsystems] = strdup(p);
+                       if (!tmp[nr_subsystems])
+                               goto out_free;
+                       nr_subsystems++;
+               }
        }
        fclose(f);
 
+       free(line);
        if (!nr_subsystems) {
                ERROR("No cgroup subsystems found");
                return false;
@@ -799,6 +813,7 @@ static bool collect_subsytems(void)
        return true;
 
 out_free:
+       free(line);
        fclose(f);
        free_subsystems();
        return false;