From 48ef41a33592bbcf4dac441f13ce4555257a3e7b Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 20 Dec 2017 19:41:06 +0100
Subject: [PATCH] sd-bus: add API to optionally set a sender field on all
 outgoing messages

This is useful on direct connections to generate messages with valid
sender fields.

This is particularly useful for services that are accessible both
through direct connections and the broker, as it allows clients to
install matches on the sender service name, and they work the same in
both cases.
---
 src/libsystemd/libsystemd.sym        |  3 +++
 src/libsystemd/sd-bus/bus-internal.h |  1 +
 src/libsystemd/sd-bus/bus-message.c  |  9 +++++++++
 src/libsystemd/sd-bus/sd-bus.c       | 29 ++++++++++++++++++++++++++++
 src/systemd/sd-bus.h                 |  3 +++
 5 files changed, 45 insertions(+)

diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym
index 27f3219ee2..5a07344175 100644
--- a/src/libsystemd/libsystemd.sym
+++ b/src/libsystemd/libsystemd.sym
@@ -543,4 +543,7 @@ global:
         sd_bus_is_ready;
         sd_bus_set_connected_signal;
         sd_bus_get_connected_signal;
+        sd_bus_set_sender;
+        sd_bus_get_sender;
+        sd_bus_message_set_sender;
 } LIBSYSTEMD_236;
diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 53f3194bef..a28f5f06f4 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -316,6 +316,7 @@ struct sd_bus {
         char *cgroup_root;
 
         char *description;
+        char *patch_sender;
 
         sd_bus_track *track_queue;
 
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 119c43bc9b..3fbb6dc306 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -5487,6 +5487,15 @@ _public_ int sd_bus_message_set_destination(sd_bus_message *m, const char *desti
         return message_append_field_string(m, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &m->destination);
 }
 
+_public_ int sd_bus_message_set_sender(sd_bus_message *m, const char *sender) {
+        assert_return(m, -EINVAL);
+        assert_return(sender, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->sender, -EEXIST);
+
+        return message_append_field_string(m, BUS_MESSAGE_HEADER_SENDER, SD_BUS_TYPE_STRING, sender, &m->sender);
+}
+
 int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz) {
         size_t total;
         void *p, *e;
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 556c217342..4156b40f91 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -154,6 +154,7 @@ static void bus_free(sd_bus *b) {
         free(b->machine);
         free(b->cgroup_root);
         free(b->description);
+        free(b->patch_sender);
 
         free(b->exec_path);
         strv_free(b->exec_argv);
@@ -274,6 +275,7 @@ _public_ int sd_bus_set_exec(sd_bus *bus, const char *path, char *const argv[])
 _public_ int sd_bus_set_bus_client(sd_bus *bus, int b) {
         assert_return(bus, -EINVAL);
         assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus->patch_sender, -EPERM);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
         bus->bus_client = !!b;
@@ -1537,6 +1539,8 @@ _public_ int sd_bus_get_bus_id(sd_bus *bus, sd_id128_t *id) {
 }
 
 static int bus_seal_message(sd_bus *b, sd_bus_message *m, usec_t timeout) {
+        int r;
+
         assert(b);
         assert(m);
 
@@ -1551,6 +1555,12 @@ static int bus_seal_message(sd_bus *b, sd_bus_message *m, usec_t timeout) {
         if (timeout == 0)
                 timeout = BUS_DEFAULT_TIMEOUT;
 
+        if (!m->sender && b->patch_sender) {
+                r = sd_bus_message_set_sender(m, b->patch_sender);
+                if (r < 0)
+                        return r;
+        }
+
         return sd_bus_message_seal(m, ++b->cookie, timeout);
 }
 
@@ -3959,3 +3969,22 @@ _public_ int sd_bus_get_exit_on_disconnect(sd_bus *bus) {
 
         return bus->exit_on_disconnect;
 }
+
+_public_ int sd_bus_set_sender(sd_bus *bus, const char *sender) {
+        assert_return(bus, -EINVAL);
+        assert_return(!bus->bus_client, -EPERM);
+        assert_return(!sender || service_name_is_valid(sender), -EINVAL);
+
+        return free_and_strdup(&bus->patch_sender, sender);
+}
+
+_public_ int sd_bus_get_sender(sd_bus *bus, const char **ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!bus->patch_sender)
+                return -ENODATA;
+
+        *ret = bus->patch_sender;
+        return 0;
+}
diff --git a/src/systemd/sd-bus.h b/src/systemd/sd-bus.h
index df21b3f30e..c30ac9e6ec 100644
--- a/src/systemd/sd-bus.h
+++ b/src/systemd/sd-bus.h
@@ -154,6 +154,8 @@ int sd_bus_set_watch_bind(sd_bus *bus, int b);
 int sd_bus_get_watch_bind(sd_bus *bus);
 int sd_bus_set_connected_signal(sd_bus *bus, int b);
 int sd_bus_get_connected_signal(sd_bus *bus);
+int sd_bus_set_sender(sd_bus *bus, const char *sender);
+int sd_bus_get_sender(sd_bus *bus, const char **ret);
 
 int sd_bus_start(sd_bus *bus);
 
@@ -273,6 +275,7 @@ int sd_bus_message_set_auto_start(sd_bus_message *m, int b);
 int sd_bus_message_set_allow_interactive_authorization(sd_bus_message *m, int b);
 
 int sd_bus_message_set_destination(sd_bus_message *m, const char *destination);
+int sd_bus_message_set_sender(sd_bus_message *m, const char *sender);
 int sd_bus_message_set_priority(sd_bus_message *m, int64_t priority);
 
 int sd_bus_message_append(sd_bus_message *m, const char *types, ...);