Re: [DistroKit] [PATCH 1/8] rauc-udev: add a compatibility layer for mapping partitions

[Michael Olbrich <m.olbrich@pengutronix.de>]

On Sun, Feb 12, 2023 at 11:14:42PM +0100, Roland Hieber wrote:
> When we add RAUC support for different platforms later, we need a way to
> specify their respective root partitions in RAUC's system.conf; however,
> the names of the actual partitions can differ on different hardware
> platforms. Add a short udev rule that can add symlinks to the actual
> partitions based on the device tree compatible. This way we can refer to
> the partitions in system.conf using the symlinks on all boards that we
> want to support.
> 
> This commit only adds a stub for now; we will add the code that creates
> the actual symlinks for each hardware in later commits.
> 
> Signed-off-by: Roland Hieber <rhi@pengutronix.de>
> ---
>  configs/ptxconfig                             |  1 +
>  projectroot/usr/lib/udev/of_base_compatible   |  4 ++
>  .../lib/udev/rules.d/90-rauc-partitions.rules | 12 ++++++
>  rules/rauc-udev.in                            |  8 ++++
>  rules/rauc-udev.make                          | 37 +++++++++++++++++++
>  5 files changed, 62 insertions(+)
>  create mode 100755 projectroot/usr/lib/udev/of_base_compatible
>  create mode 100644 projectroot/usr/lib/udev/rules.d/90-rauc-partitions.rules
>  create mode 100644 rules/rauc-udev.in
>  create mode 100644 rules/rauc-udev.make
> 
> diff --git a/configs/ptxconfig b/configs/ptxconfig
> index 3c8c001aaf8e..a6a3f29afb53 100644
> --- a/configs/ptxconfig
> +++ b/configs/ptxconfig
> @@ -3,6 +3,7 @@
>  # PTXdist 2022.12.0
>  #
>  PTXCONF_DATAPARTITION=y
> +PTXCONF_RAUC_UDEV=y
>  
>  #
>  # ------------------------------------
> diff --git a/projectroot/usr/lib/udev/of_base_compatible b/projectroot/usr/lib/udev/of_base_compatible
> new file mode 100755
> index 000000000000..6b59c9cc569d
> --- /dev/null
> +++ b/projectroot/usr/lib/udev/of_base_compatible
> @@ -0,0 +1,4 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: 0-BSD
> +# SPDX-FileCopyrightText: 2021 Roland Hieber, Pengutronix <rhi@pengutronix.de>
> +printf 'OF_BASE_COMPATIBLE="%s"\n' "$(xargs -0  printf "%s " < /sys/firmware/devicetree/base/compatible)"

This seems overly complicated. Why do you need xargs and two printf here?

Michael

> diff --git a/projectroot/usr/lib/udev/rules.d/90-rauc-partitions.rules b/projectroot/usr/lib/udev/rules.d/90-rauc-partitions.rules
> new file mode 100644
> index 000000000000..0300e8b9daad
> --- /dev/null
> +++ b/projectroot/usr/lib/udev/rules.d/90-rauc-partitions.rules
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: 0-BSD
> +# SPDX-FileCopyrightText: 2021 Roland Hieber, Pengutronix <rhi@pengutronix.de>
> +
> +ACTION=="remove", GOTO="rauc_partitions_end"
> +SUBSYSTEM!="block", GOTO="rauc_partitions_end"
> +
> +IMPORT{program}="of_base_compatible"
> +
> +# Add symlinks named /dev/disk/by-usage/{data,rootfs0,rootfs1} pointing
> +# to the correct partitions based on the device tree compatible
> +
> +LABEL="rauc_partitions_end"
> diff --git a/rules/rauc-udev.in b/rules/rauc-udev.in
> new file mode 100644
> index 000000000000..4e90343ba2dc
> --- /dev/null
> +++ b/rules/rauc-udev.in
> @@ -0,0 +1,8 @@
> +## SECTION=project_specific
> +
> +config RAUC_UDEV
> +	tristate
> +	prompt "rauc udev rules"
> +	select UDEV if RUNTIME
> +	help
> +	  udev rules for cross-hardware-compatible partition symlinks
> diff --git a/rules/rauc-udev.make b/rules/rauc-udev.make
> new file mode 100644
> index 000000000000..6a806fc43e34
> --- /dev/null
> +++ b/rules/rauc-udev.make
> @@ -0,0 +1,37 @@
> +# -*-makefile-*-
> +#
> +# Copyright (C) 2021 by Roland Hieber, Pengutronix <rhi@pengutronix.de>
> +#
> +# For further information about the PTXdist project and license conditions
> +# see the README file.
> +#
> +
> +#
> +# We provide this package
> +#
> +PACKAGES-$(PTXCONF_RAUC_UDEV) += rauc-udev
> +
> +RAUC_UDEV_VERSION	:= 1
> +RAUC_UDEV_LICENSE	:= 0-BSD
> +
> +# ----------------------------------------------------------------------------
> +# Target-Install
> +# ----------------------------------------------------------------------------
> +
> +$(STATEDIR)/rauc-udev.targetinstall:
> +	@$(call targetinfo)
> +
> +	@$(call install_init, rauc-udev)
> +	@$(call install_fixup,rauc-udev,PRIORITY,optional)
> +	@$(call install_fixup,rauc-udev,SECTION,base)
> +	@$(call install_fixup,rauc-udev,AUTHOR,"Roland Hieber, Pengutronix <rhi@pengutronix.de>")
> +	@$(call install_fixup,rauc-udev,DESCRIPTION,missing)
> +
> +	@$(call install_alternative, rauc-udev, 0, 0, 0755, /usr/lib/udev/of_base_compatible)
> +	@$(call install_alternative, rauc-udev, 0, 0, 0644, /usr/lib/udev/rules.d/90-rauc-partitions.rules)
> +
> +	@$(call install_finish,rauc-udev)
> +
> +	@$(call touch)
> +
> +# vim: syntax=make
> -- 
> 2.30.2
> 
> 
> 

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