tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy

GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.

With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.

The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).

This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.

Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:

       #define _cleanup_(function) __attribute__((cleanup(function)))

Or similar, to make the gcc feature easier to use.

Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.

See #2008.

3 files changed, 14 insertions, 29 deletions

diff --git a/src/shared/bus-util.c b/src/shared/bus-util.c
index 8775808da4..6c24150326 100644
--- a/src/shared/bus-util.c
+++ b/src/shared/bus-util.c
@@ -181,7 +181,7 @@ int bus_event_loop_with_idle(
 }
 
 int bus_name_has_owner(sd_bus *c, const char *name, sd_bus_error *error) {
-        _cleanup_bus_message_unref_ sd_bus_message *rep = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *rep = NULL;
         int r, has_owner = 0;
 
         assert(c);
@@ -207,7 +207,7 @@ int bus_name_has_owner(sd_bus *c, const char *name, sd_bus_error *error) {
 }
 
 static int check_good_user(sd_bus_message *m, uid_t good_user) {
-        _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+        _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
         uid_t sender_uid;
         int r;
 
@@ -257,8 +257,8 @@ int bus_test_polkit(
                 return 1;
 #ifdef ENABLE_POLKIT
         else {
-                _cleanup_bus_message_unref_ sd_bus_message *request = NULL;
-                _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *request = NULL;
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
                 int authorized = false, challenge = false;
                 const char *sender, **k, **v;
 
@@ -361,7 +361,7 @@ static void async_polkit_query_free(AsyncPolkitQuery *q) {
 }
 
 static int async_polkit_callback(sd_bus_message *reply, void *userdata, sd_bus_error *error) {
-        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
         AsyncPolkitQuery *q = userdata;
         int r;
 
@@ -399,7 +399,7 @@ int bus_verify_polkit_async(
                 sd_bus_error *error) {
 
 #ifdef ENABLE_POLKIT
-        _cleanup_bus_message_unref_ sd_bus_message *pk = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *pk = NULL;
         AsyncPolkitQuery *q;
         const char *sender, **k, **v;
         sd_bus_message_handler_t callback;
@@ -587,7 +587,7 @@ int bus_check_peercred(sd_bus *c) {
 }
 
 int bus_connect_system_systemd(sd_bus **_bus) {
-        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
         int r;
 
         assert(_bus);
@@ -641,7 +641,7 @@ int bus_connect_system_systemd(sd_bus **_bus) {
 }
 
 int bus_connect_user_systemd(sd_bus **_bus) {
-        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
         _cleanup_free_ char *ee = NULL;
         const char *e;
         int r;
@@ -907,8 +907,8 @@ int bus_print_property(const char *name, sd_bus_message *property, bool all) {
 }
 
 int bus_print_all_properties(sd_bus *bus, const char *dest, const char *path, char **filter, bool all) {
-        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         int r;
 
         assert(bus);
@@ -1091,7 +1091,7 @@ int bus_message_map_all_properties(
                 const struct bus_properties_map *map,
                 void *userdata) {
 
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         int r;
 
         assert(m);
@@ -1197,8 +1197,8 @@ int bus_map_all_properties(
                 const struct bus_properties_map *map,
                 void *userdata) {
 
-        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         int r;
 
         assert(bus);
diff --git a/src/shared/bus-util.h b/src/shared/bus-util.h
index 3925c10fde..ec731d375e 100644
--- a/src/shared/bus-util.h
+++ b/src/shared/bus-util.h
@@ -137,21 +137,6 @@ typedef struct UnitInfo {
 
 int bus_parse_unit_info(sd_bus_message *message, UnitInfo *u);
 
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus*, sd_bus_unref);
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus*, sd_bus_flush_close_unref);
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus_slot*, sd_bus_slot_unref);
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus_message*, sd_bus_message_unref);
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus_creds*, sd_bus_creds_unref);
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus_track*, sd_bus_track_unref);
-
-#define _cleanup_bus_unref_ _cleanup_(sd_bus_unrefp)
-#define _cleanup_bus_flush_close_unref_ _cleanup_(sd_bus_flush_close_unrefp)
-#define _cleanup_bus_slot_unref_ _cleanup_(sd_bus_slot_unrefp)
-#define _cleanup_bus_message_unref_ _cleanup_(sd_bus_message_unrefp)
-#define _cleanup_bus_creds_unref_ _cleanup_(sd_bus_creds_unrefp)
-#define _cleanup_bus_track_unref_ _cleanup_(sd_bus_slot_unrefp)
-#define _cleanup_bus_error_free_ _cleanup_(sd_bus_error_free)
-
 #define BUS_DEFINE_PROPERTY_GET_ENUM(function, name, type)              \
         int function(sd_bus *bus,                                       \
                      const char *path,                                  \
diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
index 0313b0946f..0d7892ac1e 100644
--- a/src/shared/logs-show.c
+++ b/src/shared/logs-show.c
@@ -1241,7 +1241,7 @@ int show_journal_by_unit(
                 bool system_unit,
                 bool *ellipsized) {
 
-        _cleanup_journal_close_ sd_journal*j = NULL;
+        _cleanup_(sd_journal_closep) sd_journal *j = NULL;
         int r;
 
         assert(mode >= 0);