From ff975efb2e88dcd5221a2f0d76c4c87e85b821a8 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 22 Jan 2014 23:36:06 +0100
Subject: [PATCH] bus: when we cannot bus activate a service because we go
 down, drop one message from the queue

---
 TODO                               |  1 -
 src/core/busname.c                 |  2 +-
 src/libsystemd/sd-bus/bus-kernel.c | 13 +++++++++++++
 src/libsystemd/sd-bus/bus-kernel.h |  2 ++
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/TODO b/TODO
index b76db091e..9406ce852 100644
--- a/TODO
+++ b/TODO
@@ -166,7 +166,6 @@ Features:
   - bus proxy should fake seclabel when connecting to kdbus
   - allow updating attach flags during runtime
   - pid1: peek into activating message when activating a service
-  - when service activation failed, drop one message from the activator queue
 
 * sd-event
   - allow multiple signal handlers per signal?
diff --git a/src/core/busname.c b/src/core/busname.c
index 9b6bf07d9..0d19311db 100644
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -337,8 +337,8 @@ static void busname_enter_running(BusName *n) {
                 log_debug_unit(UNIT(n)->id, "Suppressing activation request on %s since unit stop is scheduled.", UNIT(n)->id);
 
                 /* Flush all queued activation reqeuest by closing and reopening the connection */
+                bus_kernel_drop_one(n->starter_fd);
 
-                busname_close_fd(n);
                 busname_enter_listening(n);
                 return;
         }
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index a33e7a323..b46cada64 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -1476,3 +1476,16 @@ int bus_kernel_try_close(sd_bus *bus) {
 
         return 0;
 }
+
+int bus_kernel_drop_one(int fd) {
+        struct kdbus_cmd_recv recv = {
+                .flags = KDBUS_RECV_DROP
+        };
+
+        assert(fd >= 0);
+
+        if (ioctl(fd, KDBUS_CMD_MSG_RECV, &recv) < 0)
+                return -errno;
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/bus-kernel.h b/src/libsystemd/sd-bus/bus-kernel.h
index e9f776d9f..de02b84f8 100644
--- a/src/libsystemd/sd-bus/bus-kernel.h
+++ b/src/libsystemd/sd-bus/bus-kernel.h
@@ -79,3 +79,5 @@ int kdbus_translate_request_name_flags(uint64_t sd_bus_flags, uint64_t *kdbus_fl
 int kdbus_translate_attach_flags(uint64_t sd_bus_flags, uint64_t *kdbus_flags);
 
 int bus_kernel_try_close(sd_bus *bus);
+
+int bus_kernel_drop_one(int fd);
-- 
2.30.2