bus-proxyd: improve compatibility with dbus-1

'GetConnectionUnixProcessID', 'GetConnectionUnixUser' and
'GetConnectionSELinuxSecurityContext' methods should return
'NameHasNoOwner' error (if chosen name is not available on bus)
with more detailed description - like dbus-1:

Could not get PID of name 'org.freedesktop.test': no such name.
Could not get UID of name 'org.freedesktop.test': no such name.
Could not get security context of name 'org.freedesktop.test': no such name.

Otherwise we have only laconic message without proper dbus error:

Error System.Error.ENXIO: No such device or address

1 files changed, 33 insertions, 3 deletions

diff --git a/src/bus-proxyd/bus-proxyd.c b/src/bus-proxyd/bus-proxyd.c
index 52498f33d2..1bd7feed7a 100644
--- a/src/bus-proxyd/bus-proxyd.c
+++ b/src/bus-proxyd/bus-proxyd.c
@@ -643,27 +643,57 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                 return synthetic_reply_method_return(m, NULL);
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "GetConnectionSELinuxSecurityContext")) {
+                const char *name;
                 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
-                r = get_creds_by_message(a, m, SD_BUS_CREDS_SELINUX_CONTEXT, &creds, NULL);
+                r = sd_bus_message_read(m, "s", &name);
+                if (r < 0)
+                        return r;
+
+                r = get_creds_by_name(a, name, SD_BUS_CREDS_SELINUX_CONTEXT, &creds, NULL);
+                if (r == -ESRCH || r == -ENXIO) {
+                        sd_bus_error_setf(&error, SD_BUS_ERROR_NAME_HAS_NO_OWNER, "Could not get security context of name '%s': no such name.", name);
+                        return synthetic_reply_method_errno(m, r, &error);
+                }
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);
 
                 return synthetic_reply_method_return(m, "y", creds->label, strlen(creds->label));
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "GetConnectionUnixProcessID")) {
+                const char *name;
                 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
-                r = get_creds_by_message(a, m, SD_BUS_CREDS_PID, &creds, NULL);
+                r = sd_bus_message_read(m, "s", &name);
+                if (r < 0)
+                        return r;
+
+                r = get_creds_by_name(a, name, SD_BUS_CREDS_PID, &creds, NULL);
+                if (r == -ESRCH || r == -ENXIO) {
+                        sd_bus_error_setf(&error, SD_BUS_ERROR_NAME_HAS_NO_OWNER, "Could not get PID of name '%s': no such name.", name);
+                        return synthetic_reply_method_errno(m, r, &error);
+                }
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);
 
                 return synthetic_reply_method_return(m, "u", (uint32_t) creds->pid);
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "GetConnectionUnixUser")) {
+                const char *name;
                 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
-                r = get_creds_by_message(a, m, SD_BUS_CREDS_UID, &creds, NULL);
+                r = sd_bus_message_read(m, "s", &name);
+                if (r < 0)
+                        return r;
+
+                r = get_creds_by_name(a, name, SD_BUS_CREDS_UID, &creds, NULL);
+                if (r == -ESRCH || r == -ENXIO) {
+                        sd_bus_error_setf(&error, SD_BUS_ERROR_NAME_HAS_NO_OWNER, "Could not get UID of name '%s': no such name.", name);
+                        return synthetic_reply_method_errno(m, r, &error);
+                }
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);