systemd/0001-core-create-or-remove-unit-bus-name-slots-always-together.patch

109 lines
4.4 KiB
Diff

From a5b07847950c603605acf85b472b210cd2da40fb Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 23 Dec 2019 16:48:18 +0100
Subject: [PATCH] core: create/remove unit bus name slots always together
When a service unit watches a bus name (i.e. because of BusName= being
set), then we do two things: we install a match slot to watch how its
ownership changes, and we inquire about the current owner. Make sure we
always do both together or neither.
This in particular fixes a corner-case memleak when destroying bus
connections, since we never freed the GetNameOwner() bus slots when
destroying a bus when they were still ongoing.
---
src/core/dbus.c | 11 ++++-------
src/core/unit.c | 32 +++++++++++++++++++++-----------
2 files changed, 25 insertions(+), 18 deletions(-)
diff --git a/src/core/dbus.c b/src/core/dbus.c
index 3c40f29..cef1789 100644
--- a/src/core/dbus.c
+++ b/src/core/dbus.c
@@ -1051,13 +1051,10 @@ static void destroy_bus(Manager *m, sd_bus **bus) {
/* Make sure all bus slots watching names are released. */
HASHMAP_FOREACH(u, m->watch_bus, i) {
- if (!u->match_bus_slot)
- continue;
-
- if (sd_bus_slot_get_bus(u->match_bus_slot) != *bus)
- continue;
-
- u->match_bus_slot = sd_bus_slot_unref(u->match_bus_slot);
+ if (u->match_bus_slot && sd_bus_slot_get_bus(u->match_bus_slot) == *bus)
+ u->match_bus_slot = sd_bus_slot_unref(u->match_bus_slot);
+ if (u->get_name_owner_slot && sd_bus_slot_get_bus(u->get_name_owner_slot) == *bus)
+ u->get_name_owner_slot = sd_bus_slot_unref(u->get_name_owner_slot);
}
/* Get rid of tracked clients on this bus */
diff --git a/src/core/unit.c b/src/core/unit.c
index 5cf16c6..8781132 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -3238,12 +3238,13 @@ static int get_name_owner_handler(sd_bus_message *message, void *userdata, sd_bu
int unit_install_bus_match(Unit *u, sd_bus *bus, const char *name) {
const char *match;
+ int r;
assert(u);
assert(bus);
assert(name);
- if (u->match_bus_slot)
+ if (u->match_bus_slot || u->get_name_owner_slot)
return -EBUSY;
match = strjoina("type='signal',"
@@ -3253,19 +3254,27 @@ int unit_install_bus_match(Unit *u, sd_bus *bus, const char *name) {
"member='NameOwnerChanged',"
"arg0='", name, "'");
- int r = sd_bus_add_match_async(bus, &u->match_bus_slot, match, signal_name_owner_changed, NULL, u);
+ r = sd_bus_add_match_async(bus, &u->match_bus_slot, match, signal_name_owner_changed, NULL, u);
if (r < 0)
return r;
- return sd_bus_call_method_async(bus,
- &u->get_name_owner_slot,
- "org.freedesktop.DBus",
- "/org/freedesktop/DBus",
- "org.freedesktop.DBus",
- "GetNameOwner",
- get_name_owner_handler,
- u,
- "s", name);
+ r = sd_bus_call_method_async(
+ bus,
+ &u->get_name_owner_slot,
+ "org.freedesktop.DBus",
+ "/org/freedesktop/DBus",
+ "org.freedesktop.DBus",
+ "GetNameOwner",
+ get_name_owner_handler,
+ u,
+ "s", name);
+ if (r < 0) {
+ u->match_bus_slot = sd_bus_slot_unref(u->match_bus_slot);
+ return r;
+ }
+
+ log_unit_debug(u, "Watching D-Bus name '%s'.", name);
+ return 0;
}
int unit_watch_bus_name(Unit *u, const char *name) {
@@ -3288,6 +3297,7 @@ int unit_watch_bus_name(Unit *u, const char *name) {
r = hashmap_put(u->manager->watch_bus, name, u);
if (r < 0) {
u->match_bus_slot = sd_bus_slot_unref(u->match_bus_slot);
+ u->get_name_owner_slot = sd_bus_slot_unref(u->get_name_owner_slot);
return log_warning_errno(r, "Failed to put bus name to hashmap: %m");
}
--
1.8.3.1