[Buildroot] [PATCH v2 2/5] package/busybox: add modules-load init script

[Yann E. MORIN <yann.morin.1998@free.fr>]

Carlos, All,

On 2020-04-18 19:14 -0300, unixmania at gmail.com spake thusly:
> From: Carlos Santos <unixmania@gmail.com>
> 
> Use some scripting to mimic the systemd "modules-load" and the OpenRC
> "modules" services (load kernel modules based on static configuration).
> 
> At the moment package/busybox/S02modules-load is a symlink to the kmod
> script, since it works with both versions of the "modprobe" utility.
> 
> Signed-off-by: Carlos Santos <unixmania@gmail.com>
> 
> package/busybox/
> 
> ---
> CC: "Yann E. MORIN" <yann.morin.1998@free.fr>
> ---
> Changes v1->v2:
> - Rename S02modules-load to S11modules-load to ensure that it runs after
>   S10mdev and S10udev, which both are going to trigger cold-plug events
>   that may in turn trigger module loading, as observed by Yann E. MORIN.
> ---
>  package/busybox/S11modules-load |  1 +
>  package/busybox/busybox.mk      | 12 ++++++++++++
>  2 files changed, 13 insertions(+)
>  create mode 120000 package/busybox/S11modules-load
> 
> diff --git a/package/busybox/S11modules-load b/package/busybox/S11modules-load
> new file mode 120000
> index 0000000000..44623673ff
> --- /dev/null
> +++ b/package/busybox/S11modules-load
> @@ -0,0 +1 @@
> +../kmod/S11modules-load
> \ No newline at end of file

I like that the script is shared between the two packages.

But please make that state prominent in the header of the file, with
something like:

    #!/bin/sh
    # NOTE: this file is used both by kmod and busybox

> diff --git a/package/busybox/busybox.mk b/package/busybox/busybox.mk
> index 5d5f3e92bd..3512bf77b5 100644
> --- a/package/busybox/busybox.mk
> +++ b/package/busybox/busybox.mk
> @@ -264,6 +264,17 @@ define BUSYBOX_INSTALL_LOGGING_SCRIPT
>  endef
>  endif
>  
> +# Only install our modules-load script if no other package does it.
> +ifeq ($(BR2_PACKAGE_KMOD_TOOLS),)
> +define BUSYBOX_INSTALL_MODULES_SCRIPT
> +	if grep -q CONFIG_MODPROBE=y $(@D)/.config; \
> +	then \
> +		$(INSTALL) -m 0755 -D package/busybox/S11modules-load \
> +			$(TARGET_DIR)/etc/init.d/S11modules-load; \
> +	fi
> +endef
> +endif

So far, the heuristic to install a file from busybox was to install it
in no-clobber mode, and guarantee the build ordering.

Since the build ordering is already guaranteed, we should only have to
test if the startup script already exists before we isntall it.

Regards,
Yann E. MORIN.

>  # Only install our sysctl scripts if no other package does it.
>  ifeq ($(BR2_PACKAGE_PROCPS_NG),)
>  define BUSYBOX_INSTALL_SYSCTL_SCRIPT
> @@ -368,6 +379,7 @@ define BUSYBOX_INSTALL_INIT_SYSV
>  	$(BUSYBOX_INSTALL_MDEV_SCRIPT)
>  	$(BUSYBOX_INSTALL_LOGGING_SCRIPT)
>  	$(BUSYBOX_INSTALL_WATCHDOG_SCRIPT)
> +	$(BUSYBOX_INSTALL_MODULES_SCRIPT)
>  	$(BUSYBOX_INSTALL_SYSCTL_SCRIPT)
>  	$(BUSYBOX_INSTALL_TELNET_SCRIPT)
>  endef
> -- 
> 2.18.2
> 

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