Re: [PATCH kernel-helper] kernel hooks: flag pending reboot after installing a new kernel

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

Am 13.10.26 um 13:47 schrieb Jonas Theisen:
> Ship a postinst.d hook that writes /run/reboot-required and records
> the kernel package in /run/reboot-required.pkgs, similar to
> the hooks shipped by unattended-upgrades on Debian and
> update-notifier on Ubuntu. Tools like needrestart or monitoring checks
> can then notice that the newly installed kernel is not running yet,
> without requiring one of those packages to be installed.

Any reference to those docs/code/... that describe these file (paths)
would be appreciated here.

> 
> Skip this when configuring the currently running kernel, as no reboot
> is needed then.
> 
> Came up in https://forum.proxmox.com/threads/156352/
> 
> Signed-off-by: Jonas Theisen <j.theisen@proxmox.com>
> ---
>  src/proxmox-boot/Makefile                |  2 ++
>  src/proxmox-boot/proxmox-reboot-required | 19 +++++++++++++++++++
>  2 files changed, 21 insertions(+)
>  create mode 100755 src/proxmox-boot/proxmox-reboot-required
> 
> diff --git a/src/proxmox-boot/Makefile b/src/proxmox-boot/Makefile
> index 044a024..d9e1c3d 100644
> --- a/src/proxmox-boot/Makefile
> +++ b/src/proxmox-boot/Makefile
> @@ -1,4 +1,5 @@
>  KERNEL_HOOKSCRIPTS = proxmox-auto-removal zz-proxmox-boot
> +KERNEL_POSTINST_HOOKSCRIPTS = proxmox-reboot-required
>  INITRAMFS_HOOKSCRIPTS = proxmox-boot-sync
>  SHARE_FILES = functions
>  GRUB_CFG_SNIPPET = 000_proxmox_boot_header
> @@ -17,6 +18,7 @@ all:
>  install:
>  	install -d $(POSTINSTHOOKDIR)
>  	install -m 0755 $(KERNEL_HOOKSCRIPTS) $(POSTINSTHOOKDIR)
> +	install -m 0755 $(KERNEL_POSTINST_HOOKSCRIPTS) $(POSTINSTHOOKDIR)
>  	install -d $(POSTRMHOOKDIR)
>  	install -m 0755 $(KERNEL_HOOKSCRIPTS) $(POSTRMHOOKDIR)
>  	install -d $(POSTINITRAMFSHOOKDIR)
> diff --git a/src/proxmox-boot/proxmox-reboot-required b/src/proxmox-boot/proxmox-reboot-required
> new file mode 100755
> index 0000000..ccb01cd
> --- /dev/null
> +++ b/src/proxmox-boot/proxmox-reboot-required
> @@ -0,0 +1,19 @@
> +#! /bin/sh
> +set -e
> +
> +# Flag that a reboot is needed to boot the newly installed kernel, following the convention used by
> +# update-notifier and unattended-upgrades, so that tools like needrestart or monitoring checks
> +# notice it. Reconfiguring the currently running kernel does not require a reboot.
> +
> +version="$1"
> +
> +[ -n "$version" ] || exit 0
> +[ "$version" != "$(uname -r)" ] || exit 0
> +[ -d /run ] || exit 0
> +
> +pkg="${DPKG_MAINTSCRIPT_PACKAGE:-proxmox-kernel-$version}"
> +
> +echo "*** System restart required ***" > /run/reboot-required

That's always truncating any existing reboot-required file though?
Or doesn't that matter because it will be either not there or contain
exactly this string? In any case, needs either fixing or mentioning
that its fine in the commit message and maybe even a short 

Let's also use printf over echo, avoids various edge cases and makes
trailing newline and parameter handling more explicit.

> +if ! grep -qxF "$pkg" /run/reboot-required.pkgs 2>/dev/null; then
> +	echo "$pkg" >> /run/reboot-required.pkgs

same here w.r.t. using printf.

> +fi