tree-wide: introduce free_and_replace helper

It's a common pattern, so add a helper for it. A macro is necessary
because a function that takes a pointer to a pointer would be type specific,
similarly to cleanup functions. Seems better to use a macro.

3 files changed, 6 insertions, 22 deletions

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 06c156a623..8cc7a8e765 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -1591,11 +1591,7 @@ int config_parse_fdname(
                 return 0;
         }
 
-        free(s->fdname);
-        s->fdname = p;
-        p = NULL;
-
-        return 0;
+        return free_and_replace(s->fdname, p);
 }
 
 int config_parse_service_sockets(
@@ -2052,9 +2048,7 @@ int config_parse_working_directory(
                         return 0;
                 }
 
-                free(c->working_directory);
-                c->working_directory = k;
-                k = NULL;
+                free_and_replace(c->working_directory, k);
 
                 c->working_directory_home = false;
         }
diff --git a/src/core/mount.c b/src/core/mount.c
index 15619dffe3..da480001e1 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -1484,17 +1484,9 @@ static int mount_setup_unit(
 
         MOUNT(u)->from_proc_self_mountinfo = true;
 
-        free(p->what);
-        p->what = w;
-        w = NULL;
-
-        free(p->options);
-        p->options = o;
-        o = NULL;
-
-        free(p->fstype);
-        p->fstype = f;
-        f = NULL;
+        free_and_replace(p->what, w);
+        free_and_replace(p->options, o);
+        free_and_replace(p->fstype, f);
 
         if (load_extras) {
                 r = mount_add_extras(MOUNT(u));
diff --git a/src/core/service.c b/src/core/service.c
index 63045ede55..c949de9cbe 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -3088,9 +3088,7 @@ static void service_notify_message(Unit *u, pid_t pid, char **tags, FDSet *fds)
 
                 if (!streq_ptr(s->status_text, t)) {
 
-                        free(s->status_text);
-                        s->status_text = t;
-                        t = NULL;
+                        free_and_replace(s->status_text, t);
 
                         notify_dbus = true;
                 }