cgfsng: get_cgroup_path: return the cgroup path not full mounted path

Add a temporary workaround for talking to containers started with the
buggy monitor.  We can remove it sometime after 2.0 release.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

diff --git a/src/lxc/cgfsng.c b/src/lxc/cgfsng.c
index 90b8358c150785b26e30e7a2b67811c04173a07b..add95fc0aa862e782eea64c0ed748fedb1580873 100644 (file)
--- a/src/lxc/cgfsng.c
+++ b/src/lxc/cgfsng.c
@@ -1344,7 +1344,25 @@ static const char *cgfsng_get_cgroup(void *hdata, const char *subsystem)
        if (!h)
                return NULL;
 
-       return h->fullcgpath;
+       return h->fullcgpath ? h->fullcgpath + strlen(h->mountpoint) : NULL;
+}
+
+/*
+ * Given a cgroup path returned from lxc_cmd_get_cgroup_path, build a
+ * full path, which must be freed by the caller.
+ */
+static char *build_full_cgpath_from_monitorpath(struct hierarchy *h,
+                                               const char *inpath,
+                                               const char *filename)
+{
+       /*
+        * XXX Remove this case after 2.0 release.  It's for dealing with
+        * containers spawned under the old buggy cgfsng which wasn't around
+        * for long.
+        */
+       if (strncmp(inpath, "/sys/fs/cgroup/", 15) == 0)
+               return must_make_path(inpath, filename, NULL);
+       return must_make_path(h->mountpoint, inpath, filename, NULL);
 }
 
 static bool cgfsng_attach(const char *name, const char *lxcpath, pid_t pid)
@@ -1369,15 +1387,14 @@ static bool cgfsng_attach(const char *name, const char *lxcpath, pid_t pid)
                if (!path) // not running
                        continue;
 
-               fullpath = must_make_path(path, "cgroup.procs", NULL);
+               fullpath = build_full_cgpath_from_monitorpath(h, path, "cgroup.procs");
+               free(path);
                if (lxc_write_to_file(fullpath, pidstr, len, false) != 0) {
                        SYSERROR("Failed to attach %d to %s", (int)pid, fullpath);
                        free(fullpath);
-                       free(path);
                        free_handler_data(d);
                        return false;
                }
-               free(path);
                free(fullpath);
        }
 
@@ -1414,7 +1431,7 @@ static int cgfsng_get(const char *filename, char *value, size_t len, const char
 
        h = get_hierarchy(d, subsystem);
        if (h) {
-               char *fullpath = must_make_path(path, filename, NULL);
+               char *fullpath = build_full_cgpath_from_monitorpath(h, path, filename);
                ret = lxc_read_from_file(fullpath, value, len);
                free(fullpath);
        }
@@ -1454,7 +1471,7 @@ static int cgfsng_set(const char *filename, const char *value, const char *name,
 
        h = get_hierarchy(d, subsystem);
        if (h) {
-               char *fullpath = must_make_path(path, filename, NULL);
+               char *fullpath = build_full_cgpath_from_monitorpath(h, path, filename);
                ret = lxc_write_to_file(fullpath, value, strlen(value), false);
                free(fullpath);
        }