I think we should close this bug or re-purpose it to silence those warnings in common cases.

Pushed the change into master of libassuan (to be 3.0).

Pushed to GnuPG master. Let us test. For my machine of Debian GNU/Linux, Wine emulation (Windows 32-bit, Windows 64-bit), make check goes all well.
After confirming the implementation, I'd like to put it into gpgrt.

Implemented in rA9110945ce625: Implement timeout in assuan_sock_connect_byname..

Actually, it's not 'connect' system call, but 'CONNECT' request which matters. The use of SOCKS in libassuan is that it always connects to SOCKS server at localhost.
So, other than the special case of erroneous configuration of TOR, introducing timeout handling to the initial connection to the SOCKS server makes less sense.

I see the point of use of int.
For backward compatibility, the semantics of 0 should remain as default timeout (let kernel decide == 120 sec, usually), -1 would be meaning immediately (only success when local).

Why can't we keep the signed int? Do we ever need such a long timeout. We could for example define -1 as use default timeout.

assuan_sock_connect_byname may be extended to change the third argument (now int reserved) to unsigned int timeout.
It's a kind of API change, but ABI wise, the impact is minimum.

My understanding is that: selftest in Kleo does call assuan_socket_connect (possibly in kleopatra/src/libkleopatraclient/core/command.cpp), and it didn't send nonce correctly.

Thanks! I don't understand why your fix helps as Kleopatra never calls assuan_socket_connect on the server side, but it helps. :) So this is probably called indirectly and I don't see it.

I found an issue in the assuan code of client side. This might be the cause of the server failure for nonce.

The followup of this issue for libassuan is: https://dev.gnupg.org/T6324

What I mean is that our socket emulation is encapsulated in libgcrypt and details should not be visible to the caller. Further libassuan and kleopatra might be build against different libc versions and thus the used structures might also differ.

From the NEWS assuan_sock_set_sockaddr_un was only added in 2014, years after the UIServer code was really last modified.

The question is why Kleopatra does not use assuan_sock_set_sockaddr_un as we do in GnuPG. See for example
https://dev.gnupg.org/source/gnupg/browse/master/kbx/keyboxd.c$1124 - was this a workaround back when we had no support for Unicode? assuan_sock_set_sockaddr_un and assuan_sock_get_nonce work together and their internal workings should be opaque to the caller.

Btw. This is how Kleopatra creates the socket: https://dev.gnupg.org/source/kleo/browse/master/src/uiserver/uiserver_win.cpp$34 which does not use a function that would set is_socket=1. My naive fix would be:

works

Fixed by reverting to 2.5.5

Problem is that Kleopatra uses the latest libassuan from Git and not the released version. Replacing the libassuan DLL with the one from the gnupg directory fixes the bug.

On Windows, closing/inheriting handles is different to POSIX.
https://devblogs.microsoft.com/oldnewthing/20111216-00/?p=8873
https://devblogs.microsoft.com/oldnewthing/20130426-00/?p=4543
https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessw
https://learn.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-startupinfoexw
https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-initializeprocthreadattributelist
https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-updateprocthreadattribute
https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-deleteprocthreadattributelist

We should consider to break the Assuan API maybe we can do that without too many problems for the current use cases.

I'm going to use gnupg_process_* prefix for the functions.

Last two points are for future changes of assuan internal; For the case of controlling fds in detail, it is possible to use spawn callback controlling fds by the routine and let no-touching (inherit) by the spawn function.

I don't understand the last two points: This is only about the three standard descriptors but how shall we supply more descriptors? At least in GPGME we definitely need more.

Evaluating again, I'd like to change spawn functions like this one in libgpg-error:

Examining again, I realized that the current spawn API (not published yet, only available in libgpg-error master) is not that useful in general (or difficult to use), while it works somehow.

Here is the change of GnuPG to use new spawn functions from libgpg-error:

Merged PIPE connection part into master.

For the spawn_cb, I reconsider. Having three calls complicates use, and it is actually not needed. In the case of pthread_atfork, it is needed, because fork may be used deeply in some functions. In our use cases of spawn function, prepare part of the callback can be called before calling spawn, and parent part of the callback can be called after calling spawn.

I decide use of pid_t, as there are different semantics between POSIX and Windows, *and* there is a problem of MinGW-w64. I introduce gpgrt_process_t, instead.

Another thing when we define a type which represents process.
For pid_t, MinGW-w64 has a bug: https://bugzilla.redhat.com/show_bug.cgi?id=1397787 (or https://sourceforge.net/p/mingw-w64/mailman/mingw-w64-public/thread/1456671365-21759-1-git-send-email-sw%40weilnetz.de/).
(1) GetCurrentProcessId always returns 32-bit (DWORD), so, it can be represented in 32-bit (although DWORD is unsigned).
(2) POSIX requires pid_t should be signed integer https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html
(3) Original MinGW defines pid_t as int (in include/sys/type.h by _pid_t). (checked in mingwrt-5.4.2)

@werner - having another argument might be useful. Indeed, pthread_atfork has three callback functions as its arguments (prepare, parent, and child).

I general I agree.

To have clear semantics, I propose a change to gpgrt_spawn_process_fd (calling SPAWN_CB, instead of AFTER_FORK_CB, and give it return value), and exporting gpgrt_close_all_fds to users.

By the commit rE43c1e85fe29a: spawn: Expose spawn functions., spawn functions are exposed now. The API is compatible to the one of internal functions in GnuPG master (2.3).
Semantics is not well-defined portably for:

• gpgrt_spawn_process: EXCEPT only makes sense in POSIX. User could expect that the API does closing all fds except fds specified by EXCEPT in POSIX.
• gpgrt_spawn_process_fd: AFTER_FORK_CB only makes sense in POSIX. User could specify the callback so that it can control sigmask, envvar, open/close/dup-ing file descriptors, making sure releasing some resources beforehand, etc.

I see. I understand the use cases for POSIX to keep some file descriptors.

without this list we don't have an option to keep file descriptors open; its not just stderr but for example log files and descriptors which pare passed by other meands than libassuan functions.

• assuan_pipe_connect and internal _assuan_spawn

By 1/N...5/N, it works. And it shows the API needs clarification and possible modification/fixes; As written in the comment of system-w32.c, fd == POSIX fd semantics is good, which asks API/ABI break.

Push the change.

New release of libassuan is expected to make sure it's cleared off.

@gniibe Thanks!

In the repo, for all related software, it's done.

Note that versions since 2020-11-07 to 2021-07-03 have major problem with non-POSIX shell, which doesn't support $(..) construct.

Thank you.

Backported to GnuPG 2.2.

Applied the changes.

Pushed the solution which doesn't require new flag for libassuan.

^-- I withdraw the solution (with error value) above.

Or, it would be good for client side (in this case, gpg-agent) to specify the flag in the inquiry callback, that is, it's a kind of transient flag for a single transaction.

Revised version with new flag ASSUAN_CLEAR_INQUIRY_DATA.

For this particular issue of assuan_inquire, if it's needed, the point we should fix is:

GPGME has its own system hooks to provide a (different) solution for portability (Windows and POSIX).