Do not realloc strings, which are already in the hashmap as keys

This prevents corruption of the hashmap, because we would free() the
keys in the hashmap, if the unit is already in there, with the same
cgroup path.

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 5a1c3adacd19af3f8ff2c67ebcb98ea7ab2e53cd..3eeb47575424f3c853594d122df5e2fe74ee6273 100644 (file)
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -382,6 +382,7 @@ static CGroupControllerMask unit_get_siblings_mask(Unit *u) {
 static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
         char *path = NULL;
         int r;
+        bool is_in_hash = false;
 
         assert(u);
 
@@ -390,8 +391,14 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
                 return -ENOMEM;
 
         r = hashmap_put(u->manager->cgroup_unit, path, u);
-        if (r < 0)
+        if (r == 0)
+                is_in_hash = true;
+
+        if (r < 0) {
+                free(path);
+                log_error("cgroup %s exists already: %s", path, strerror(-r));
                 return r;
+        }
 
         /* First, create our own group */
         r = cg_create_with_mask(mask, path);
@@ -405,9 +412,12 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
                         log_error("Failed to migrate cgroup %s: %s", path, strerror(-r));
         }
 
-        /* And remember the new data */
-        free(u->cgroup_path);
-        u->cgroup_path = path;
+        if (!is_in_hash) {
+                /* And remember the new data */
+                free(u->cgroup_path);
+                u->cgroup_path = path;
+        }
+
         u->cgroup_realized = true;
         u->cgroup_mask = mask;
 

diff --git a/src/core/unit.c b/src/core/unit.c
index 27119b0cd72880797ed770d762b6dc30dc827c36..ab313b9b91b6faa4e8bfdd53a82c9c3e331d2e23 100644 (file)
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2329,7 +2329,7 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
                         free(u->cgroup_path);
                         u->cgroup_path = s;
 
-                        hashmap_put(u->manager->cgroup_unit, s, u);
+                        assert(hashmap_put(u->manager->cgroup_unit, s, u) == 1);
                         continue;
                 }