Subject: Re: [PATCH v2 1/7] gen_init_cpio: write to fd instead of stdout stream

From: Nicolas Schier <[email-masked]>
Date: Mon, 18 Aug 2025 20:40:29 +0200

On Thu, Aug 14, 2025 at 03:17:59PM +1000, David Disseldorp wrote:
> In preparation for more efficient archiving using copy_file_range(),
> switch from writing archive data to stdout to using STDOUT_FILENO and
> I/O via write(), dprintf(), etc.
> Basic I/O error handling is added to cover cases such as ENOSPC. Partial
> writes are treated as errors.
> 
> Signed-off-by: David Disseldorp <[email-masked]>
> ---
>  usr/gen_init_cpio.c | 139 ++++++++++++++++++++++++++------------------
>  1 file changed, 81 insertions(+), 58 deletions(-)
> 
> diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
> index edcdb8abfa31c..d8779fe4b8f1f 100644
> --- a/usr/gen_init_cpio.c
> +++ b/usr/gen_init_cpio.c
[...]
> @@ -96,23 +103,24 @@ static void cpio_trailer(void)
>  		0,			/* rminor */
>  		(unsigned)strlen(name)+1, /* namesize */
>  		0);			/* chksum */
> -	push_hdr(s);
> -	push_rest(name);
> +	offset += len;
>  
> -	while (offset % 512) {
> -		putchar(0);
> -		offset++;
> -	}
> +	if (len != CPIO_HDR_LEN
> +	 || push_rest(name) < 0
> +	 || push_pad(padlen(offset, 512)) < 0)

Thanks, patch looks good to me.

Just a minor coding style bike shedding: Starting continuation lines
with '||' seems to be rather unusual in Linux code:

    $ git grep -Ee '^\s*(\|\||&&)' **/*.c | wc -l
    64
    $ git grep -Ee '(\|\||&&)$' **/*.c | wc -l
    2553

Kind regards,
Nicolas