From: Junio C Hamano <gitster@pobox•com>
To: Johannes Schindelin <johannes.schindelin@gmx•de>
Cc: git@vger•kernel.org, Johannes Sixt <j6t@kdbg•org>
Subject: Re: [PATCH v2] mingw: emulate write(2) that fails with a EPIPE
Date: Thu, 17 Dec 2015 11:22:49 -0800 [thread overview]
Message-ID: <xmqqwpscc22e.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <ca357ac83a9990d6c88b637b76c6cc7f30d3f7be.1450372051.git.johannes.schindelin@gmx.de> (Johannes Schindelin's message of "Thu, 17 Dec 2015 18:08:15 +0100 (CET)")
Johannes Schindelin <johannes.schindelin@gmx•de> writes:
> On Windows, when writing to a pipe fails, errno is always
> EINVAL. However, Git expects it to be EPIPE.
>
> According to the documentation, there are two cases in which write()
> triggers EINVAL: the buffer is NULL, or the length is odd but the mode
> is 16-bit Unicode (the broken pipe is not mentioned as possible cause).
> Git never sets the file mode to anything but binary, therefore we know
> that errno should actually be EPIPE if it is EINVAL and the buffer is
> not NULL.
>
> See https://msdn.microsoft.com/en-us/library/1570wh78.aspx for more
> details.
>
> This works around t5571.11 failing with v2.6.4 on Windows.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx•de>
> ---
> compat/mingw.c | 17 +++++++++++++++++
> compat/mingw.h | 3 +++
> 2 files changed, 20 insertions(+)
>
> diff --git a/compat/mingw.c b/compat/mingw.c
> index 90bdb1e..5edea29 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -394,6 +394,23 @@ int mingw_fflush(FILE *stream)
> return ret;
> }
>
> +#undef write
> +ssize_t mingw_write(int fd, const void *buf, size_t len)
> +{
> + ssize_t result = write(fd, buf, len);
> +
> + if (result < 0 && errno == EINVAL && buf) {
> + /* check if fd is a pipe */
> + HANDLE h = (HANDLE) _get_osfhandle(fd);
> + if (GetFileType(h) == FILE_TYPE_PIPE)
> + errno = EPIPE;
> + else
> + errno = EINVAL;
> + }
> +
> + return result;
> +}
> +
> int mingw_access(const char *filename, int mode)
> {
> wchar_t wfilename[MAX_PATH];
> diff --git a/compat/mingw.h b/compat/mingw.h
> index 738865c..57ca477 100644
> --- a/compat/mingw.h
> +++ b/compat/mingw.h
> @@ -210,6 +210,9 @@ FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream);
> int mingw_fflush(FILE *stream);
> #define fflush mingw_fflush
>
> +ssize_t mingw_write(int fd, const void *buf, size_t len);
> +#define write mingw_write
> +
> int mingw_access(const char *filename, int mode);
> #undef access
> #define access mingw_access
PLEASE DON'T DO THE BELOW TO THE SAME MESSAGE AS THE PATCH ITSELF.
"git apply" would not read and understand the next line as a natural
language sentence for obvious reasons.
> Interdiff vs v1:
>
> diff --git a/compat/mingw.c b/compat/mingw.c
> index 90bdb1e..5edea29 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -394,6 +394,23 @@ int mingw_fflush(FILE *stream)
> return ret;
> }
>
> +#undef write
> +ssize_t mingw_write(int fd, const void *buf, size_t len)
> +{
> + ssize_t result = write(fd, buf, len);
> +
> + if (result < 0 && errno == EINVAL && buf) {
> + /* check if fd is a pipe */
> + HANDLE h = (HANDLE) _get_osfhandle(fd);
> + if (GetFileType(h) == FILE_TYPE_PIPE)
> + errno = EPIPE;
> + else
> + errno = EINVAL;
> + }
> +
> + return result;
> +}
> +
> int mingw_access(const char *filename, int mode)
> {
> wchar_t wfilename[MAX_PATH];
> diff --git a/compat/mingw.h b/compat/mingw.h
> index 2aca347..57ca477 100644
> --- a/compat/mingw.h
> +++ b/compat/mingw.h
> @@ -210,22 +210,7 @@ FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream);
> int mingw_fflush(FILE *stream);
> #define fflush mingw_fflush
>
> -static inline ssize_t mingw_write(int fd, const void *buf, size_t len)
> -{
> - ssize_t result = write(fd, buf, len);
> -
> - if (result < 0 && errno == EINVAL && buf) {
> - /* check if fd is a pipe */
> - HANDLE h = (HANDLE) _get_osfhandle(fd);
> - if (GetFileType(h) == FILE_TYPE_PIPE)
> - errno = EPIPE;
> - else
> - errno = EINVAL;
> - }
> -
> - return result;
> -}
> -
> +ssize_t mingw_write(int fd, const void *buf, size_t len);
> #define write mingw_write
>
> int mingw_access(const char *filename, int mode);
next prev parent reply other threads:[~2015-12-17 19:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-16 12:14 [PATCH] mingw: emulate write(2) that fails with a EPIPE Johannes Schindelin
2015-12-16 18:35 ` Junio C Hamano
2015-12-17 9:39 ` Johannes Schindelin
2015-12-17 16:40 ` Junio C Hamano
2015-12-17 17:08 ` Johannes Schindelin
2015-12-16 19:47 ` Eric Sunshine
2015-12-16 20:36 ` Junio C Hamano
2015-12-17 9:37 ` Johannes Schindelin
2015-12-17 17:08 ` [PATCH v2] " Johannes Schindelin
2015-12-17 19:22 ` Junio C Hamano [this message]
2015-12-18 16:10 ` Johannes Schindelin
2015-12-18 20:57 ` Johannes Sixt
2015-12-21 16:59 ` Junio C Hamano
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