systemctl: make sure we terminate the bus connection first, and then close the pager (#3550)

If "systemctl -H" is used, let's make sure we first terminate the bus
connection, and only then close the pager. If done in this order ssh will get
an EOF on stdin (as we speak D-Bus through ssh's stdin/stdout), and then
terminate. This makes sure the standard error we were invoked on is released by
ssh, and only that makes sure we don't deadlock on the pager which waits for
all clients closing its input pipe.

(Similar fixes for the various other xyzctl tools that support both pagers and
-H)

Fixes: #3543

6 files changed, 13 insertions, 7 deletions

diff --git a/src/libsystemd/sd-bus/busctl.c b/src/libsystemd/sd-bus/busctl.c
index bfe967bfb0..eb042e9c81 100644
--- a/src/libsystemd/sd-bus/busctl.c
+++ b/src/libsystemd/sd-bus/busctl.c
@@ -1987,7 +1987,7 @@ static int busctl_main(sd_bus *bus, int argc, char *argv[]) {
 }
 
 int main(int argc, char *argv[]) {
-        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        sd_bus *bus = NULL;
         int r;
 
         log_parse_environment();
@@ -2078,6 +2078,7 @@ int main(int argc, char *argv[]) {
         r = busctl_main(bus, argc, argv);
 
 finish:
+        sd_bus_flush_close_unref(bus);
         pager_close();
 
         strv_free(arg_matches);
diff --git a/src/locale/localectl.c b/src/locale/localectl.c
index 4865335349..81afb4909f 100644
--- a/src/locale/localectl.c
+++ b/src/locale/localectl.c
@@ -656,7 +656,7 @@ static int localectl_main(sd_bus *bus, int argc, char *argv[]) {
 }
 
 int main(int argc, char*argv[]) {
-        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        sd_bus *bus = NULL;
         int r;
 
         setlocale(LC_ALL, "");
@@ -676,6 +676,7 @@ int main(int argc, char*argv[]) {
         r = localectl_main(bus, argc, argv);
 
 finish:
+        sd_bus_flush_close_unref(bus);
         pager_close();
 
         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
diff --git a/src/login/loginctl.c b/src/login/loginctl.c
index 1c75565636..0fc2720b43 100644
--- a/src/login/loginctl.c
+++ b/src/login/loginctl.c
@@ -1554,7 +1554,7 @@ static int loginctl_main(int argc, char *argv[], sd_bus *bus) {
 }
 
 int main(int argc, char *argv[]) {
-        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        sd_bus *bus = NULL;
         int r;
 
         setlocale(LC_ALL, "");
@@ -1576,6 +1576,8 @@ int main(int argc, char *argv[]) {
         r = loginctl_main(argc, argv, bus);
 
 finish:
+        sd_bus_flush_close_unref(bus);
+
         pager_close();
         polkit_agent_close();
 
diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index afe5026373..583d2a21e7 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -2751,7 +2751,7 @@ static int machinectl_main(int argc, char *argv[], sd_bus *bus) {
 }
 
 int main(int argc, char*argv[]) {
-        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        sd_bus *bus = NULL;
         int r;
 
         setlocale(LC_ALL, "");
@@ -2773,6 +2773,7 @@ int main(int argc, char*argv[]) {
         r = machinectl_main(argc, argv, bus);
 
 finish:
+        sd_bus_flush_close_unref(bus);
         pager_close();
         polkit_agent_close();
 
diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index feb93cad8e..4b34d24ee8 100644
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -7938,6 +7938,8 @@ int main(int argc, char*argv[]) {
         }
 
 finish:
+        release_busses();
+
         pager_close();
         ask_password_agent_close();
         polkit_agent_close();
@@ -7949,8 +7951,6 @@ finish:
         strv_free(arg_wall);
         free(arg_root);
 
-        release_busses();
-
         /* Note that we return r here, not EXIT_SUCCESS, so that we can implement the LSB-like return codes */
         return r < 0 ? EXIT_FAILURE : r;
 }
diff --git a/src/timedate/timedatectl.c b/src/timedate/timedatectl.c
index b7871f81aa..7f61cf0181 100644
--- a/src/timedate/timedatectl.c
+++ b/src/timedate/timedatectl.c
@@ -480,7 +480,7 @@ static int timedatectl_main(sd_bus *bus, int argc, char *argv[]) {
 }
 
 int main(int argc, char *argv[]) {
-        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        sd_bus *bus = NULL;
         int r;
 
         setlocale(LC_ALL, "");
@@ -500,6 +500,7 @@ int main(int argc, char *argv[]) {
         r = timedatectl_main(bus, argc, argv);
 
 finish:
+        sd_bus_flush_close_unref(bus);
         pager_close();
 
         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;