[PATCH 0/1] MR10591: winebth.sys: Support building with dbus older than 1.12.

[Vitaly Lipatov (＠lav)]

DBUS_MESSAGE_ITER_INIT_CLOSED and dbus_message_iter_abandon_container_if_open
were added in dbus 1.12. Provide a fallback definition for the macro and load
the function optionally via dlsym to allow building on systems with older dbus.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10591

[PATCH 1/1] winebth.sys: Support building with dbus older than 1.12.

[Vitaly Lipatov]

From: Vitaly Lipatov <[e-mail]>

DBUS_MESSAGE_ITER_INIT_CLOSED and dbus_message_iter_abandon_container_if_open
were added in dbus 1.12. Provide a fallback definition for the macro and load
the function optionally via dlsym to allow building on systems with older dbus.
---
 dlls/winebth.sys/dbus.c | 15 ++++++++++++++-
 dlls/winebth.sys/dbus.h |  1 -
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/dlls/winebth.sys/dbus.c b/dlls/winebth.sys/dbus.c
index aa2cef1cc0a..8cd72d85092 100644
--- a/dlls/winebth.sys/dbus.c
+++ b/dlls/winebth.sys/dbus.c
@@ -35,6 +35,11 @@
 
 #ifdef SONAME_LIBDBUS_1
 #include <dbus/dbus.h>
+
+/* DBUS_MESSAGE_ITER_INIT_CLOSED was added in dbus 1.12. */
+#ifndef DBUS_MESSAGE_ITER_INIT_CLOSED
+#define DBUS_MESSAGE_ITER_INIT_CLOSED { {0} }
+#endif
 #endif
 
 #include <ntstatus.h>
@@ -129,6 +134,9 @@ const int bluez_timeout = -1;
 DBUS_FUNCS;
 #undef DO_FUNC
 
+/* dbus_message_iter_abandon_container_if_open was added in dbus 1.12. */
+static typeof(dbus_message_iter_abandon_container) *p_dbus_message_iter_abandon_container_if_open;
+
 static BOOL load_dbus_functions( void )
 {
     void *handle = dlopen( SONAME_LIBDBUS_1, RTLD_NOW );
@@ -143,6 +151,10 @@ static BOOL load_dbus_functions( void )
     }
     DBUS_FUNCS;
 #undef DO_FUNC
+
+    /* dbus_message_iter_abandon_container_if_open is optional (dbus >= 1.12). */
+    p_dbus_message_iter_abandon_container_if_open = dlsym( handle, "dbus_message_iter_abandon_container_if_open" );
+
     return TRUE;
 
 failed:
@@ -1163,7 +1175,8 @@ NTSTATUS bluez_gatt_characteristic_read( void *connection, void *watcher_ctx, st
     p_dbus_message_unref( request );
     return STATUS_PENDING;
 failed:
-    p_dbus_message_iter_abandon_container_if_open( &args_iter, &dict_iter );
+    if (p_dbus_message_iter_abandon_container_if_open)
+        p_dbus_message_iter_abandon_container_if_open( &args_iter, &dict_iter );
     p_dbus_message_unref( request );
     return status;
 }
diff --git a/dlls/winebth.sys/dbus.h b/dlls/winebth.sys/dbus.h
index 511e8caf25b..4cbf37883df 100644
--- a/dlls/winebth.sys/dbus.h
+++ b/dlls/winebth.sys/dbus.h
@@ -84,7 +84,6 @@
     DO_FUNC(dbus_message_is_signal); \
     DO_FUNC(dbus_message_iter_append_basic); \
     DO_FUNC(dbus_message_iter_abandon_container); \
-    DO_FUNC(dbus_message_iter_abandon_container_if_open); \
     DO_FUNC(dbus_message_iter_close_container); \
     DO_FUNC(dbus_message_iter_get_arg_type); \
     DO_FUNC(dbus_message_iter_get_element_type); \
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10591

[Vibhav Pant (＠vibhavp)]

Vibhav Pant (@vibhavp) commented about dlls/winebth.sys/dbus.c:
> p_dbus_message_unref( request );
>      return STATUS_PENDING;
>  failed:
> -    p_dbus_message_iter_abandon_container_if_open( &args_iter, &dict_iter );
> +    if (p_dbus_message_iter_abandon_container_if_open)
> +        p_dbus_message_iter_abandon_container_if_open( &args_iter, &dict_iter );

Wouldn't this cause a leak if `dbus_message_iter_abandon_container_if_open` is not available? I think it's better to not use this method entirely, add a boolean to track whether the container has been initialized, and call `dbus_message_iter_abandon_container` on failure if it's true.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10591#note_135771