[PATCH v2 1/2] cpio: add support for --ignore-devno like GNU cpio

[Ariadne Conill]

Hi,

Just following up on this patch and the other one.  It would be nice to 
get them upstream.

Ariadne

On Mon, 28 Jun 2021, Ariadne Conill wrote:

> The --ignore-devno option is used to set device numbers to (0, 0).
> This can be useful in verifying whether a CPIO archive is reproducible.
>
> function                                             old     new   delta
> cpio_o                                               922     961     +39
> .rodata                                            78407   78422     +15
> bbconfig_config_bz2                                 6161    6167      +6
> packed_usage                                       25770   25764      -6
> ------------------------------------------------------------------------------
> (add/remove: 0/0 grow/shrink: 3/1 up/down: 60/-6)              Total: 54 bytes
>
> Signed-off-by: Ariadne Conill <ariadne at dereferenced.org>
> ---
> archival/cpio.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/archival/cpio.c b/archival/cpio.c
> index d84f6937d..4d386d38d 100644
> --- a/archival/cpio.c
> +++ b/archival/cpio.c
> @@ -38,6 +38,13 @@
> //config:	depends on FEATURE_CPIO_O
> //config:	help
> //config:	Passthrough mode. Rarely used.
> +//config:
> +//config:config FEATURE_CPIO_IGNORE_DEVNO
> +//config:	bool "Support --ignore-devno like GNU cpio"
> +//config:	default y
> +//config:	depends on FEATURE_CPIO_O && LONG_OPTS
> +//config:	help
> +//config:	Optionally ignore device numbers when creating archives.
>
> //applet:IF_CPIO(APPLET(cpio, BB_DIR_BIN, BB_SUID_DROP))
>
> @@ -75,6 +82,9 @@
> //usage:     "\n	-R USER[:GRP]	Set owner of created files"
> //usage:     "\n	-L	Dereference symlinks"
> //usage:     "\n	-0	Input is separated by NULs"
> +//usage:	IF_FEATURE_CPIO_IGNORE_DEVNO(
> +//usage:     "\n	--ignore-devno"
> +//usage:	)
>
> /* GNU cpio 2.9 --help (abridged):
>
> @@ -162,11 +172,13 @@ enum {
> 	IF_FEATURE_CPIO_P(OPTBIT_PASSTHROUGH,)
> 	IF_LONG_OPTS(     OPTBIT_QUIET      ,)
> 	IF_LONG_OPTS(     OPTBIT_2STDOUT    ,)
> +	IF_FEATURE_CPIO_IGNORE_DEVNO(OPTBIT_IGNORE_DEVNO,)
> 	OPT_CREATE             = IF_FEATURE_CPIO_O((1 << OPTBIT_CREATE     )) + 0,
> 	OPT_FORMAT             = IF_FEATURE_CPIO_O((1 << OPTBIT_FORMAT     )) + 0,
> 	OPT_PASSTHROUGH        = IF_FEATURE_CPIO_P((1 << OPTBIT_PASSTHROUGH)) + 0,
> 	OPT_QUIET              = IF_LONG_OPTS(     (1 << OPTBIT_QUIET      )) + 0,
> 	OPT_2STDOUT            = IF_LONG_OPTS(     (1 << OPTBIT_2STDOUT    )) + 0,
> +	OPT_IGNORE_DEVNO       = IF_FEATURE_CPIO_IGNORE_DEVNO((1 << OPTBIT_IGNORE_DEVNO)) + 0,
> };
>
> #define OPTION_STR "it0uvdmLF:R:"
> @@ -304,6 +316,11 @@ static NOINLINE int cpio_o(void)
> 			}
> 		}
>
> +#if ENABLE_FEATURE_CPIO_IGNORE_DEVNO
> +		if (option_mask32 & OPT_IGNORE_DEVNO)
> +			st.st_dev = st.st_rdev = 0;
> +#endif
> +
> 		bytes += printf("070701"
> 				"%08X%08X%08X%08X%08X%08X%08X"
> 				"%08X%08X%08X%08X" /* GNU cpio uses uppercase hex */
> @@ -379,6 +396,9 @@ int cpio_main(int argc UNUSED_PARAM, char **argv)
> 		"null\0"         No_argument       "0"
> 		"quiet\0"        No_argument       "\xff"
> 		"to-stdout\0"    No_argument       "\xfe"
> +#if ENABLE_FEATURE_CPIO_IGNORE_DEVNO
> +		"ignore-devno\0" No_argument	   "\xfd"
> +#endif
> 		;
> #endif
>
> -- 
> 2.32.0
>
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