bus: add new sd_bus_creds object to encapsulate process credentials

This way we can unify handling of credentials that are attached to
messages, or can be queried for bus name owners or connection peers.

This also adds the ability to extend incomplete credential information
with data from /proc,

Also, provide a convenience call that will automatically determine the
most appropriate credential object for an incoming message, by using the
the attached information if possible, the sending name information if
available and otherwise the peer's credentials.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/login/logind-user-dbus.c b/src/login/logind-user-dbus.c
index 6a77e33eea..b034515203 100644
--- a/src/login/logind-user-dbus.c
+++ b/src/login/logind-user-dbus.c
@@ -247,6 +247,7 @@ int user_object_find(sd_bus *bus, const char *path, const char *interface, void
         assert(m);
 
         if (streq(path, "/org/freedesktop/login1/user/self")) {
+                _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
                 sd_bus_message *message;
                 pid_t pid;
 
@@ -254,9 +255,13 @@ int user_object_find(sd_bus *bus, const char *path, const char *interface, void
                 if (!message)
                         return 0;
 
-                r = sd_bus_get_owner_pid(bus, sd_bus_message_get_sender(message), &pid);
+                r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_PID, &creds);
                 if (r < 0)
-                        return 0;
+                        return r;
+
+                r = sd_bus_creds_get_pid(creds, &pid);
+                if (r < 0)
+                        return r;
 
                 r = manager_get_user_by_pid(m, pid, &user);
                 if (r <= 0)