[PATCH v2 03/10] base-files: upgrade: add get_image_dd()

[Philip Prindeville]

Comments…


> On Nov 9, 2020, at 7:22 PM, Yousong Zhou <yszhou4tech at gmail.com> wrote:
> 
> This is mainly to handle stderr message "Broken pipe", "F+P records
> in/out" by common pattern "xcat | dd .."
> 
> Ref: https://bugs.openwrt.org/index.php?do=details&task_id=3140
> Reported-by: Philip Prindeville <philipp at redfish-solutions.com>
> Signed-off-by: Yousong Zhou <yszhou4tech at gmail.com>
> ---
> package/base-files/files/lib/upgrade/common.sh | 6 ++++++
> 1 file changed, 6 insertions(+)
> 
> diff --git a/package/base-files/files/lib/upgrade/common.sh b/package/base-files/files/lib/upgrade/common.sh
> index e12dfc9678..6c09908ee3 100644
> --- a/package/base-files/files/lib/upgrade/common.sh
> +++ b/package/base-files/files/lib/upgrade/common.sh
> @@ -94,6 +94,12 @@ get_image() { # <source> [ <command> ]
> 	$cmd <"$from"
> }
> 
> +get_image_dd() {
> +	local from="$1"; shift
> +
> +	( get_image "$from" | dd "$@" ) 2>&1 | grep -v -E ': Broken pipe| records (in|out)'


Can you through stdout onto another descriptor first, like 3, then move 2 to 1, run the grep, and then after the grep put 3 back onto 1?

I don’t like the idea of co-mingling stdout and stderr…

Thanks



> +}
> +
> get_magic_word() {
> 	(get_image "$@" | dd bs=2 count=1 | hexdump -v -n 2 -e '1/1 "%02x"') 2>/dev/null
> }