From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: "René Scharfe" <l.s.r@web.de>
Cc: Jeff King <peff@peff.net>, Junio C Hamano <gitster@pobox.com>,
git@vger.kernel.org
Subject: Re: [PATCH v2] pipe_command(): mark stdin descriptor as non-blocking
Date: Mon, 8 Aug 2022 14:55:39 +0200 (CEST) [thread overview]
Message-ID: <099911o8-43q1-o29s-5s36-34r5qn37nq8n@tzk.qr> (raw)
In-Reply-To: <362560ca-1e37-bab3-e508-4d5bf5429e66@web.de>
[-- Attachment #1: Type: text/plain, Size: 3132 bytes --]
Hi René,
On Sun, 7 Aug 2022, René Scharfe wrote:
> Am 05.08.2022 um 17:36 schrieb Jeff King:
> > On Wed, Aug 03, 2022 at 11:56:13PM +0200, René Scharfe wrote:
> > >> int enable_nonblock(int fd)
> >> {
> >> + DWORD mode;
> >> + HANDLE handle = winansi_get_osfhandle(fd);
> >> + if (!handle)
> >> + return -1;
> >> + if (!GetNamedPipeHandleState(handle, &mode, NULL, NULL, NULL, NULL, 0))
> >> + return -1;
> >> + if (mode & PIPE_NOWAIT)
> >> + return 0;
> >> + mode |= PIPE_NOWAIT;
> >> + if (!SetNamedPipeHandleState(handle, &mode, NULL, NULL))
> >> + return -1;
> >> return 0;
> >> }
> >
> > This looks plausibly correct to me. ;) We might want to change the name
> > of the compat layer to enable_pipe_nonblock(), since one assumes from
> > the function names this only works for pipes.
>
> Or how about this? Squashable. Needs testing.
>
> --- >8 ---
> Subject: [PATCH] nonblock: support Windows
>
> Implement enable_nonblock() using the Windows API. Supports only named
> and anonymous pipes for now, which suffices for the current caller.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
> compat/nonblock.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/compat/nonblock.c b/compat/nonblock.c
> index 897c099010..78923cd2c3 100644
> --- a/compat/nonblock.c
> +++ b/compat/nonblock.c
> @@ -14,9 +14,40 @@ int enable_nonblock(int fd)
>
> #else
>
> +#ifdef GIT_WINDOWS_NATIVE
Maybe use an `#elif defined(GIT_WINDOWS_NATIVE)` here? That would make the
code structures clearer, methinks.
> +
> +#include "win32.h"
> +
> +int enable_nonblock(int fd)
> +{
> + HANDLE h = (HANDLE)_get_osfhandle(fd);
> + DWORD mode;
> + DWORD type = GetFileType(h);
> + if (type == FILE_TYPE_UNKNOWN && GetLastError() != NO_ERROR) {
> + errno = EBADF;
> + return -1;
> + }
> + if (type != FILE_TYPE_PIPE)
> + BUG("unsupported file type: %lu", type);
> + if (!GetNamedPipeHandleState(h, &mode, NULL, NULL, NULL, NULL, 0)) {
> + errno = err_win_to_posix(GetLastError());
> + return -1;
> + }
> + mode |= PIPE_NOWAIT;
> + if (!SetNamedPipeHandleState(h, &mode, NULL, NULL)) {
Nice.
FWIW the documentation of `PIPE_NOWAIT` says:
Note that nonblocking mode is supported for compatibility with
Microsoft LAN Manager version 2.0 and should not be used to
achieve asynchronous input and output (I/O) with named pipes.
(see
https://docs.microsoft.com/en-us/windows/win32/api/namedpipeapi/nf-namedpipeapi-setnamedpipehandlestate
for full details)
There is little more information to be found on the interwebs, the closest
to an in-depth explanation is here:
https://devblogs.microsoft.com/oldnewthing/20110114-00/?p=11753
Even if that comment suggests that this mode is deprecated, I think it is
safe to rely on it in Git's source code.
Thanks,
Dscho
> + errno = err_win_to_posix(GetLastError());
> + return -1;
> + }
> + return 0;
> +}
> +
> +#else
> +
> int enable_nonblock(int fd)
> {
> return 0;
> }
>
> #endif
> +
> +#endif
> --
> 2.37.1.windows.1
>
next prev parent reply other threads:[~2022-08-08 12:56 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-02 4:13 [RFC/PATCH] pipe_command(): mark stdin descriptor as non-blocking Jeff King
2022-08-02 15:04 ` Junio C Hamano
2022-08-02 15:39 ` Jeff King
2022-08-02 16:16 ` Junio C Hamano
2022-08-03 3:53 ` [PATCH v2] " Jeff King
2022-08-03 16:45 ` René Scharfe
2022-08-03 17:20 ` Jeff King
2022-08-03 21:56 ` René Scharfe
2022-08-05 15:36 ` Jeff King
2022-08-05 21:13 ` René Scharfe
2022-08-07 10:15 ` René Scharfe
2022-08-07 17:41 ` Jeff King
2022-08-10 5:39 ` René Scharfe
2022-08-10 19:53 ` Jeff King
2022-08-10 22:35 ` René Scharfe
2022-08-11 8:52 ` Jeff King
2022-08-10 5:39 ` [PATCH] mingw: handle writes to non-blocking pipe René Scharfe
2022-08-10 9:07 ` Johannes Schindelin
2022-08-10 20:02 ` Jeff King
2022-08-10 22:34 ` René Scharfe
2022-08-11 8:47 ` Jeff King
2022-08-11 17:35 ` René Scharfe
2022-08-11 18:20 ` Jeff King
2022-08-14 15:37 ` René Scharfe
2022-08-17 5:39 ` Jeff King
2022-08-17 6:04 ` [PATCH v2 0/6] fix pipe_command() deadlock Jeff King
2022-08-17 6:04 ` [PATCH v2 1/6] compat: add function to enable nonblocking pipes Jeff King
2022-08-17 20:23 ` Junio C Hamano
2022-08-18 5:41 ` Jeff King
2022-08-17 6:05 ` [PATCH v2 2/6] nonblock: support Windows Jeff King
2022-08-17 6:06 ` [PATCH v2 3/6] git-compat-util: make MAX_IO_SIZE define globally available Jeff King
2022-08-17 6:08 ` [PATCH v2 4/6] pipe_command(): avoid xwrite() for writing to pipe Jeff King
2022-08-17 6:09 ` [PATCH v2 5/6] pipe_command(): handle ENOSPC when writing to a pipe Jeff King
2022-08-17 18:57 ` Junio C Hamano
2022-08-18 5:38 ` Jeff King
2022-08-17 6:10 ` [PATCH v2 6/6] pipe_command(): mark stdin descriptor as non-blocking Jeff King
2022-08-17 6:20 ` [PATCH v2 0/6] fix pipe_command() deadlock Jeff King
2022-08-19 21:19 ` René Scharfe
2022-08-20 7:04 ` Jeff King
2022-08-07 10:14 ` [PATCH v2] pipe_command(): mark stdin descriptor as non-blocking René Scharfe
2022-08-08 12:55 ` Johannes Schindelin [this message]
2022-08-08 12:59 ` Johannes Schindelin
2022-08-09 13:04 ` Jeff King
2022-08-09 22:10 ` Johannes Schindelin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=099911o8-43q1-o29s-5s36-34r5qn37nq8n@tzk.qr \
--to=johannes.schindelin@gmx.de \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=l.s.r@web.de \
--cc=peff@peff.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).