*** Bug 732796 has been marked as a duplicate of this bug. ***

Reproduced with this:

 gcc gdbus-fd-error.c `pkg-config glib-2.0 gio-2.0 gio-unix-2.0 --cflags --libs`


pvanhoof@lenny:~/Downloads$ cat /usr/lib/i386-linux-gnu/pkgconfig/gio-unix-2.0.pc
prefix=/usr
exec_prefix=${prefix}
libdir=${prefix}/lib/i386-linux-gnu
includedir=${prefix}/include

Name: GIO unix specific APIs
Description: unix specific headers for glib I/O library
Version: 2.40.0
Requires: gobject-2.0,gio-2.0
Libs: -L${libdir} -lgio-2.0
Cflags: -I${includedir}/gio-unix-2.0/
pvanhoof@lenny:~/Downloads$ 



pvanhoof@lenny:~/Downloads$ gdb ./a.out 
GNU gdb (GDB) 7.6.2 (Debian 7.6.2-1.1+b1)
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/pvanhoof/Downloads/a.out...(no debugging symbols found)...done.
(gdb) run
Starting program: /home/pvanhoof/Downloads/./a.out 
warning: Could not load shared library symbols for linux-gate.so.1.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/i686/cmov/libthread_db.so.1".
[New Thread 0xb7a47b40 (LWP 6869)]
[New Thread 0xb70ffb40 (LWP 6870)]
g_dbus_connection_real_closed: Remote peer vanished with error: Tried sending a file descriptor on unsupported stream of type GSocketOutputStream (g-io-error-quark, 0). Exiting.

Program received signal SIGTERM, Terminated.
0xb7fde424 in __kernel_vsyscall ()
(gdb) bt

+ Trace 233914

ps. Source of the example describes that you need to do this a few times from another terminal:

dbus-send --print-reply --dest=org.example.FdErrorTest /org/example/FdErrorTest org.example.FdErrorTest.Test int32:$((1024*200)) |sed 's/#\{1024\}/./g'

Some additional useful information is that on_worker_closed gets called in a thread right before that g_dbus_connection_real_closed happens on the mainloop's context.

+ Trace 233915

Continuing.
g_dbus_connection_real_closed: Remote peer vanished with error: Tried sending a file descriptor on unsupported stream of type GSocketOutputStream (g-io-error-quark, 0). Exiting.

Program received signal SIGTERM, Terminated.
[Switching to Thread 0xb7a48780 (LWP 7036)]
0xb7fde424 in __kernel_vsyscall ()
(gdb)

So this means that we reach that TODO: handle in this situation. I wonder what the TODO means.

git blame shows me David, but David is assigned so he receives this without having to put David in CC ;-)

8a3a4596 (David Zeuthen        2010-08-16 13:43:35 -0400 1340)       /* TODO: handle */


static void
write_message_cb (GObject       *source_object,
                  GAsyncResult  *res,
                  gpointer       user_data)
{
  MessageToWriteData *data = user_data;
  GError *error;

  g_mutex_lock (&data->worker->write_lock); 
  g_assert (data->worker->output_pending == PENDING_WRITE);
  data->worker->output_pending = PENDING_NONE;

  error = NULL;
  if (!write_message_finish (res, &error))
    {
      g_mutex_unlock (&data->worker->write_lock);

      /* TODO: handle */
      _g_dbus_worker_emit_disconnected (data->worker, TRUE, error);
      g_error_free (error);

      g_mutex_lock (&data->worker->write_lock);
    }

  message_written_unlocked (data->worker, data);

  g_mutex_unlock (&data->worker->write_lock);

  continue_writing (data->worker);

  message_to_write_data_free (data);
}

In the version that im debugging right now, line 1027 is this line:

if (!(data->worker->capabilities & G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING))

of the function write_message_continue_writing


Breakpoint 10, write_message_continue_writing (data=data@entry=0x8058498)
    at /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c:1027
1027	/build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c: No such file or directory.
(gdb) bt

+ Trace 233916

$4 = (MessageToWriteData *) 0x8058498
(gdb) p *data
$5 = {worker = 0xb7108cf0, message = 0x8057c60, blob = 0xb688b008 "l\002\001\001\005 \003", blob_size = 204861, 
  total_written = 0, simple = 0xb6702840}
(gdb) p *data->worker
$6 = {ref_count = 4, shared_thread_data = 0xb7109378, stopped = 0, frozen = 0, 
  capabilities = G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING, received_messages_while_frozen = 0x80520c0, stream = 0xb7101060, 
  cancellable = 0x8054950, message_received_callback = 0xb7f02370 <on_worker_message_received>, 
  message_about_to_be_sent_callback = 0xb7eff990 <on_worker_message_about_to_be_sent>, 
  disconnected_callback = 0xb7eff740 <on_worker_closed>, user_data = 0x8056848, socket = 0xb71060d0, read_lock = {
    p = 0xb710a650, i = {3071321680, 0}}, read_buffer = 0xb6701200 "l\001", read_buffer_allocated_size = 4096, 
  read_buffer_cur_size = 0, read_buffer_bytes_wanted = 16, read_fd_list = 0x0, read_ancillary_messages = 0x0, 
  read_num_ancillary_messages = 0, output_pending = PENDING_WRITE, write_lock = {p = 0xb7108ea8, i = {3071315624, 0}}, 
  write_queue = 0x80520d0, write_num_messages_written = 2, write_num_messages_flushed = 0, write_pending_flushes = 0x0, 
  pending_close_attempts = 0x0, close_expected = 0}
(gdb) p *data->worker->capabilities
Attempt to take contents of a non-pointer value.
(gdb) p data->worker->capabilities
$7 = G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING
(gdb)

Sorry, last comment was a false positive, because that line is still handled without error. But I can't break in the actual error case :-(


$7 = G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING
(gdb) n
1037	in /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c
(gdb) b
Breakpoint 11 at 0xb7f16368: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1037.
(gdb) d
Delete all breakpoints? (y or n) y
(gdb) b gdbusprivate.c:1028
Breakpoint 12 at 0xb7f161a2: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1028.
(gdb) c
Continuing.
g_dbus_connection_real_closed: Remote peer vanished with error: Tried sending a file descriptor on unsupported stream of type GSocketOutputStream (g-io-error-quark, 0). Exiting.

Program received signal SIGTERM, Terminated.
[Switching to Thread 0xb7a48780 (LWP 7288)]
0xb7fde424 in __kernel_vsyscall ()
(gdb) b gdbusprivate.c:1029
Note: breakpoint 12 also set at pc 0xb7f161a2.
Breakpoint 13 at 0xb7f161a2: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1029.
(gdb) b gdbusprivate.c:1030
Breakpoint 14 at 0xb7f161c5: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1030.
(gdb) b gdbusprivate.c:1031
Note: breakpoint 14 also set at pc 0xb7f161c5.
Breakpoint 15 at 0xb7f161c5: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1031.
(gdb) b gdbusprivate.c:1033
Note: breakpoints 14 and 15 also set at pc 0xb7f161c5.
Breakpoint 16 at 0xb7f161c5: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1033.
(gdb) b gdbusprivate.c:1034
Breakpoint 17 at 0xb7f161cd: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gdbusprivate.c, line 1034.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/pvanhoof/Downloads/./a.out 
warning: Could not load shared library symbols for linux-gate.so.1.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/i686/cmov/libthread_db.so.1".
[New Thread 0xb7a47b40 (LWP 7302)]
[New Thread 0xb70ffb40 (LWP 7303)]
g_dbus_connection_real_closed: Remote peer vanished with error: Tried sending a file descriptor on unsupported stream of type GSocketOutputStream (g-io-error-quark, 0). Exiting.

Program received signal SIGTERM, Terminated.
0xb7fde424 in __kernel_vsyscall ()
(gdb)

Ok, no more being stupid and here is the more simple version of my debugging session that avoids that gdb can miss lines because of compiler optimizations or somethings.

Simple breakpoint on g_simple_async_result_set_error :-)


Program received signal SIGTERM, Terminated.
0xb7fde424 in __kernel_vsyscall ()
(gdb) b g_simple_async_result_set_error
Breakpoint 18 at 0xb7ea1ee0: file /build/glib2.0-f_gKLq/glib2.0-2.40.0/./gio/gsimpleasyncresult.c, line 716.
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/pvanhoof/Downloads/./a.out 
warning: Could not load shared library symbols for linux-gate.so.1.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/i686/cmov/libthread_db.so.1".
[New Thread 0xb7a47b40 (LWP 7308)]
[New Thread 0xb70ffb40 (LWP 7309)]

+ Trace 233917

$9 = (MessageToWriteData *) 0x8058498
(gdb) print *data
$10 = {worker = 0xb7108cf0, message = 0x8057c60, blob = 0xb688b008 "l\002\001\001\005 \003", blob_size = 204861, 
  total_written = 183360, simple = 0xb6702840}
(gdb) print *data->worker
$11 = {ref_count = 4, shared_thread_data = 0xb7109378, stopped = 0, frozen = 0, 
  capabilities = G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING, received_messages_while_frozen = 0x80520c0, stream = 0xb7101060, 
  cancellable = 0x8054950, message_received_callback = 0xb7f02370 <on_worker_message_received>, 
  message_about_to_be_sent_callback = 0xb7eff990 <on_worker_message_about_to_be_sent>, 
  disconnected_callback = 0xb7eff740 <on_worker_closed>, user_data = 0x8056848, socket = 0xb71060d0, read_lock = {
    p = 0xb710a650, i = {3071321680, 0}}, read_buffer = 0xb6701200 "l\001", read_buffer_allocated_size = 4096, 
  read_buffer_cur_size = 0, read_buffer_bytes_wanted = 16, read_fd_list = 0x0, read_ancillary_messages = 0x0, 
  read_num_ancillary_messages = 0, output_pending = PENDING_WRITE, write_lock = {p = 0xb7108ea8, i = {3071315624, 0}}, 
  write_queue = 0x80520d0, write_num_messages_written = 2, write_num_messages_flushed = 0, write_pending_flushes = 0x0, 
  pending_close_attempts = 0x0, close_expected = 0}
(gdb) print data->worker->capability
There is no member named capability.
(gdb) print data->worker->capabilities
$12 = G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING
(gdb)

This?

--- a/gio/gdbusprivate.c
+++ b/gio/gdbusprivate.c
@@ -1024,7 +1024,7 @@
       control_message = NULL;
       if (fd_list != NULL && g_unix_fd_list_get_length (fd_list) > 0)
         {
-          if (!(data->worker->capabilities & G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING))
+          if (data->worker->capabilities & ~G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING)
             {
               g_simple_async_result_set_error (simple,
                                                G_IO_ERROR,

ps. With Comment 9 applied I can still reproduce but at a different location:

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/i686/cmov/libthread_db.so.1".
[New Thread 0xb7a48b40 (LWP 17212)]
[New Thread 0xb70ffb40 (LWP 17213)]
[Thread 0xb7a48b40 (LWP 17212) exited]

+ Trace 233918

$18 = (MessageToWriteData *) 0x8058498
(gdb) print *data
$19 = {worker = 0xb7108cf0, message = 0xb6703e30, blob = 0xb688b008 "l\002\001\001\005 \003", blob_size = 204861, 
  total_written = 183360, simple = 0xb7101418}
(gdb) list
1092	  else
1093	    {
1094	#ifdef G_OS_UNIX
1095	      if (fd_list != NULL)
1096	        {
1097	          g_simple_async_result_set_error (simple,
1098	                                           G_IO_ERROR,
1099	                                           G_IO_ERROR_FAILED,
1100	                                           "Tried sending a file descriptor on unsupported stream of type %s",
1101	                                           g_type_name (G_TYPE_FROM_INSTANCE (ostream)));
(gdb) print fd_list
$20 = (GUnixFDList *) 0xb6705638
(gdb) print *fd_list
$21 = {parent_instance = {g_type_instance = {g_class = 0x8058610}, ref_count = 1, qdata = 0x0}, priv = 0xb6705630}
(gdb) print *fd_list->priv
$22 = {fds = 0x804fc28, nfd = 1}
(gdb) print *fd_list->priv->fds
$23 = 10
(gdb)

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