Re: [PATCH v1 2/4] builtin/receive-pack.c: change xwrite to write_in_full to allow large sizes.

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 26, 2024, 23:50 UTC
Message-ID: <xmqq34tekcoo.fsf@gitster.g>
In-Reply-To: <20240226220539.3494-3-randall.becker@nexbridge.ca>

"Randall S. Becker" <the.n.e.key@gmail.com> writes:

Show 5 quoted lines

> From: "Randall S. Becker" <rsbecker@nexbridge.com>
>
> This change is required because some platforms do not support file writes of
> arbitrary sizes (e.g, NonStop). xwrite ends up truncating the output to the
> maximum single I/O size possible for the destination device.

As msg[] here is 4k on-stack buffer, if the I/O size is small enough, the above may happen, and I think write-in-full is warranted here. If your I/O must be done in 1k chunks, it would be very slow to run things like writing a pack stream to clone any non-toy projects, though X-<.

Show 21 quoted lines

> Signed-off-by: Randall S. Becker <rsbecker@nexbridge.com>
> ---
>  builtin/receive-pack.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
> index db65607485..5064f3d300 100644
> --- a/builtin/receive-pack.c
> +++ b/builtin/receive-pack.c
> @@ -455,8 +455,9 @@ static void report_message(const char *prefix, const char *err, va_list params)
>  
>  	if (use_sideband)
>  		send_sideband(1, 2, msg, sz, use_sideband);
> -	else
> -		xwrite(2, msg, sz);
> +	else {
> +		write_in_full(2, msg, sz);
> +	}
>  }
>  
>  __attribute__((format (printf, 1, 2)))