Re: [PATCH] Core Update 167: Replace /etc/mtab by symlink to /proc/self/mounts

[Michael Tremer <michael.tremer@ipfire.org>]

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Hello,

> On 11 Apr 2022, at 20:14, Peter Müller <peter.mueller(a)ipfire.org> wrote:
> 
> mount, as updated via util-linux, no longer writes /etc/mtab, causing
> programs to rely on this file's content (such as the check_disk Nagios
> plugin) to stop working.
> 
> /proc/self/mounts contains all the necessary information, so it is fine
> to replace /etc/mtab by a symlink to it.
> 
> Fixes: #12843
> 
> Signed-off-by: Peter Müller <peter.mueller(a)ipfire.org>
> ---
> config/rootfiles/core/167/update.sh | 4 ++++
> lfs/cdrom                           | 4 ++--
> lfs/stage2                          | 3 ++-
> src/initscripts/system/mountfs      | 6 ------
> src/initscripts/system/partresize   | 6 ------
> 5 files changed, 8 insertions(+), 15 deletions(-)
> 
> diff --git a/config/rootfiles/core/167/update.sh b/config/rootfiles/core/167/update.sh
> index fdcb843cf..a9be60a1d 100644
> --- a/config/rootfiles/core/167/update.sh
> +++ b/config/rootfiles/core/167/update.sh
> @@ -337,6 +337,10 @@ hardlink -c -vv /lib/firmware
> # Regenerate all initrds
> dracut --regenerate-all --force
> 
> +# Replace /etc/mtab by symlink as mount no longer writes it
> +rm -vf /etc/mtab
> +ln -vs /proc/self/mounts /etc/mtab

Okay. This would work.

> +
> # Rebuild IPS rules
> perl -e "require '/var/ipfire/ids-functions.pl'; &IDS::oinkmaster();"
> /etc/init.d/suricata reload
> diff --git a/lfs/cdrom b/lfs/cdrom
> index f35ff6a35..d84f8c23c 100644
> --- a/lfs/cdrom
> +++ b/lfs/cdrom
> @@ -1,7 +1,7 @@
> ###############################################################################
> #                                                                             #
> # IPFire.org - A linux based firewall                                         #
> -# Copyright (C) 2007-2021  IPFire Team  <info(a)ipfire.org>                     #
> +# Copyright (C) 2007-2022  IPFire Team  <info(a)ipfire.org>                     #
> #                                                                             #
> # This program is free software: you can redistribute it and/or modify        #
> # it under the terms of the GNU General Public License as published by        #
> @@ -149,7 +149,7 @@ $(TARGET) : $(patsubst %,$(DIR_DL)/%,$(objects))
> 
> 	# Clear mtab (prevents .journal problems)
> 	rm -vf /etc/mtab
> -	echo > /etc/mtab
> +	ln -s /proc/self/mounts /etc/mtab

This however should not be required.

Shipping the symlink should be enough. It would be great to get rid of hacks like these.

> 	# Create filelist for packaging.
> 	BUILDTARGET="$(BUILDTARGET)" BUILD_ARCH="$(BUILD_ARCH)" KVER="$(KVER)" \
> diff --git a/lfs/stage2 b/lfs/stage2
> index 9f93babe2..39697a848 100644
> --- a/lfs/stage2
> +++ b/lfs/stage2
> @@ -87,7 +87,8 @@ endif
> 	cp -rvf $(DIR_SRC)/config/etc/* /etc;
> 	[ ! -d "$(DIR_SRC)/config/etc-$(BUILD_ARCH)" ] || cp -rvf $(DIR_SRC)/config/etc-$(BUILD_ARCH)/* /etc
> 	cp -rvf $(DIR_SRC)/config/lib/* /lib;
> -	touch /etc/{fs,m}tab
> +	touch /etc/fstab
> +	ln -s /proc/self/mounts /etc/mtab
> 	echo "$(NAME) v$(VERSION) - $(SLOGAN)" >  /etc/issue
> 	echo "===============================" >> /etc/issue
> 	echo "\n running on \s \r \m"          >> /etc/issue
> diff --git a/src/initscripts/system/mountfs b/src/initscripts/system/mountfs
> index b1533d6a2..81ed729c1 100644
> --- a/src/initscripts/system/mountfs
> +++ b/src/initscripts/system/mountfs
> @@ -31,12 +31,6 @@ case "${1}" in
> 		# Remove fsck-related file system watermarks.
> 		rm -f /fastboot /forcefsck
> 
> -		boot_mesg "Create /etc/mtab..."
> -		> /etc/mtab
> -		mount -f / || failed=1
> -		(exit ${failed})
> -		evaluate_retval
> -
> 		# This will mount all filesystems that do not have _netdev in
> 		# their option list.  _netdev denotes a network filesystem.
> 		boot_mesg "Mounting remaining file systems..."
> diff --git a/src/initscripts/system/partresize b/src/initscripts/system/partresize
> index 7605b9e2b..147405e1e 100644
> --- a/src/initscripts/system/partresize
> +++ b/src/initscripts/system/partresize
> @@ -30,12 +30,6 @@ case "${1}" in
> 			mount -o remount,rw / > /dev/null
> 			evaluate_retval
> 
> -			boot_mesg "Create /etc/mtab..."
> -			> /etc/mtab
> -			mount -f / || failed=1
> -			(exit ${failed})
> -			evaluate_retval
> -
> 			# check if serial console enabled
> 			scon="off";
> 			if [ ! "$(grep "console=ttyS0" /proc/cmdline)" == "" ]; then
> -- 
> 2.34.1