From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 10 Dec 2014 21:06:44 +0000 (+0100)
Subject: scope: make attachment of initial PIDs a bit more robust
X-Git-Tag: v218~8
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=7b3fd6313c4b07b6f822a9f979d0c22350a401d9;ds=sidebyside

scope: make attachment of initial PIDs a bit more robust
---

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 83678e6e0..35b862d5c 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -605,7 +605,6 @@ static const char *migrate_callback(CGroupControllerMask mask, void *userdata) {
 }
 
 static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
-        _cleanup_free_ char *path = NULL;
         CGroupContext *c;
         int r;
 
@@ -615,18 +614,22 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
         if (!c)
                 return 0;
 
-        path = unit_default_cgroup_path(u);
-        if (!path)
-                return log_oom();
+        if (!u->cgroup_path) {
+                _cleanup_free_ char *path = NULL;
 
-        r = hashmap_put(u->manager->cgroup_unit, path, u);
-        if (r < 0) {
-                log_error(r == -EEXIST ? "cgroup %s exists already: %s" : "hashmap_put failed for %s: %s", path, strerror(-r));
-                return r;
-        }
-        if (r > 0) {
-                u->cgroup_path = path;
-                path = NULL;
+                path = unit_default_cgroup_path(u);
+                if (!path)
+                        return log_oom();
+
+                r = hashmap_put(u->manager->cgroup_unit, path, u);
+                if (r < 0) {
+                        log_error(r == -EEXIST ? "cgroup %s exists already: %s" : "hashmap_put failed for %s: %s", path, strerror(-r));
+                        return r;
+                }
+                if (r > 0) {
+                        u->cgroup_path = path;
+                        path = NULL;
+                }
         }
 
         /* First, create our own group */
@@ -651,6 +654,21 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
         return 0;
 }
 
+int unit_attach_pids_to_cgroup(Unit *u) {
+        int r;
+        assert(u);
+
+        r = unit_realize_cgroup(u);
+        if (r < 0)
+                return r;
+
+        r = cg_attach_many_everywhere(u->manager->cgroup_supported, u->cgroup_path, u->pids, migrate_callback, u);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
 static bool unit_has_mask_realized(Unit *u, CGroupControllerMask mask) {
         assert(u);
 
diff --git a/src/core/cgroup.h b/src/core/cgroup.h
index 16d661357..7150e5e7e 100644
--- a/src/core/cgroup.h
+++ b/src/core/cgroup.h
@@ -110,6 +110,7 @@ CGroupControllerMask unit_get_target_mask(Unit *u);
 void unit_update_cgroup_members_masks(Unit *u);
 int unit_realize_cgroup(Unit *u);
 void unit_destroy_cgroup_if_empty(Unit *u);
+int unit_attach_pids_to_cgroup(Unit *u);
 
 int manager_setup_cgroup(Manager *m);
 void manager_shutdown_cgroup(Manager *m, bool delete);
diff --git a/src/core/execute.c b/src/core/execute.c
index 955090c44..5e4135e03 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1351,7 +1351,7 @@ static int exec_child(ExecCommand *command,
         }
 
         if (params->cgroup_path) {
-                err = cg_attach_everywhere(params->cgroup_supported, params->cgroup_path, 0);
+                err = cg_attach_everywhere(params->cgroup_supported, params->cgroup_path, 0, NULL, NULL);
                 if (err < 0) {
                         *error = EXIT_CGROUP;
                         return err;
diff --git a/src/core/scope.c b/src/core/scope.c
index f0efec051..e0da6e4db 100644
--- a/src/core/scope.c
+++ b/src/core/scope.c
@@ -288,11 +288,7 @@ static int scope_start(Unit *u) {
         if (!u->transient && UNIT(s)->manager->n_reloading <= 0)
                 return -ENOENT;
 
-        r = unit_realize_cgroup(u);
-        if (r < 0)
-                return log_error_errno(r, "Failed to realize cgroup: %m");
-
-        r = cg_attach_many_everywhere(u->manager->cgroup_supported, u->cgroup_path, UNIT(s)->pids);
+        r = unit_attach_pids_to_cgroup(u);
         if (r < 0)
                 return r;
 
diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c
index e595d895d..1bcba0188 100644
--- a/src/shared/cgroup-util.c
+++ b/src/shared/cgroup-util.c
@@ -1624,7 +1624,7 @@ int cg_create_everywhere(CGroupControllerMask supported, CGroupControllerMask ma
         return 0;
 }
 
-int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid) {
+int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid, cg_migrate_callback_t path_callback, void *userdata) {
         CGroupControllerMask bit = 1;
         const char *n;
         int r;
@@ -1634,8 +1634,18 @@ int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t
                 return r;
 
         NULSTR_FOREACH(n, mask_names) {
-                if (supported & bit)
+
+                if (supported & bit) {
+                        const char *p = NULL;
+
+                        if (path_callback)
+                                p = path_callback(bit, userdata);
+
+                        if (!p)
+                                p = path;
+
                         cg_attach_fallback(n, path, pid);
+                }
 
                 bit <<= 1;
         }
@@ -1643,7 +1653,7 @@ int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t
         return 0;
 }
 
-int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path, Set* pids) {
+int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path, Set* pids, cg_migrate_callback_t path_callback, void *userdata) {
         Iterator i;
         void *pidp;
         int r = 0;
@@ -1652,7 +1662,7 @@ int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path,
                 pid_t pid = PTR_TO_LONG(pidp);
                 int q;
 
-                q = cg_attach_everywhere(supported, path, pid);
+                q = cg_attach_everywhere(supported, path, pid, path_callback, userdata);
                 if (q < 0)
                         r = q;
         }
diff --git a/src/shared/cgroup-util.h b/src/shared/cgroup-util.h
index a65f515b4..5e1e445c3 100644
--- a/src/shared/cgroup-util.h
+++ b/src/shared/cgroup-util.h
@@ -126,8 +126,8 @@ int cg_slice_to_path(const char *unit, char **ret);
 typedef const char* (*cg_migrate_callback_t)(CGroupControllerMask mask, void *userdata);
 
 int cg_create_everywhere(CGroupControllerMask supported, CGroupControllerMask mask, const char *path);
-int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid);
-int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path, Set* pids);
+int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid, cg_migrate_callback_t callback, void *userdata);
+int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path, Set* pids, cg_migrate_callback_t callback, void *userdata);
 int cg_migrate_everywhere(CGroupControllerMask supported, const char *from, const char *to, cg_migrate_callback_t callback, void *userdata);
 int cg_trim_everywhere(CGroupControllerMask supported, const char *path, bool delete_root);