core: fix the CGROUP spawning error as a workaroundsubmit/tizen/20150826.112629accepted/tizen/wearable/20150826.222657accepted/tizen/tv/20150826.222642accepted/tizen/mobile/20150826.222629

When logging in and out continually, the below error occurs.

* systemd: Failed at step CGROUP spawning /usr/lib/systemd/systemd: No
such file or directory

This is mainly because the cgroup path of systemd user session does not
exists even though that cgroup is marked as 'realized'. That is
definitely bug and it is already reported into systemd mainline last
January. But there is no _right_ solution right now and it looks like a
picky problem to resolve. So I made this patch as a workaround for Tizen
TDC demonstration.

Change-Id: Ie2e164a4e4daeb88fc102e5fa88e0faca28088b0
Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>

3 files changed, 27 insertions, 0 deletions

diff --git a/src/core/service.c b/src/core/service.c
index 7781b4e626..f76ace3db8 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1058,6 +1058,19 @@ static int service_spawn(
         assert(c);
         assert(_pid);
 
+
+        /* TODO workaround code */
+        if (UNIT(s)->cgroup_realized) {
+                _cleanup_free_ char *path = NULL;
+                path = unit_default_cgroup_path(UNIT(s));
+
+                if (cg_check_cgroup_exist(path) < 0) {
+                        log_unit_error(UNIT(s)->id, "CGROUP ERROR! (%s) is already realized but not exists", UNIT(s)->id);
+                        UNIT(s)->cgroup_realized = false;
+                        UNIT(s)->cgroup_realized_mask = 0;
+                }
+        }
+
         unit_realize_cgroup(UNIT(s));
 
         r = unit_setup_exec_runtime(UNIT(s));
diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c
index dfd8689b72..db76a88ea9 100644
--- a/src/shared/cgroup-util.c
+++ b/src/shared/cgroup-util.c
@@ -1794,3 +1794,15 @@ int cg_kernel_controllers(Set *controllers) {
 
         return 0;
 }
+
+int cg_check_cgroup_exist(const char *p) {
+        const char *cc;
+        assert(p);
+
+        cc = strjoina("/sys/fs/cgroup/systemd", p);
+        if (laccess(cc, F_OK) < 0) {
+                return -errno;
+        }
+
+        return 0;
+}
diff --git a/src/shared/cgroup-util.h b/src/shared/cgroup-util.h
index 96a3d3bafa..0fc6afa300 100644
--- a/src/shared/cgroup-util.h
+++ b/src/shared/cgroup-util.h
@@ -74,6 +74,8 @@ int cg_get_path_and_check(const char *controller, const char *path, const char *
 
 int cg_pid_get_path(const char *controller, pid_t pid, char **path);
 
+int cg_check_cgroup_exist(const char *p);
+
 int cg_trim(const char *controller, const char *path, bool delete_root);
 
 int cg_rmdir(const char *controller, const char *path);