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 12 Apr 2022, at 13:01, Peter Müller <peter.mueller(a)ipfire.org> wrote:
> 
> Hello Michael,
> 
>> 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.
> 
> this sounds like you would have done that in another way...

No, I just wanted to say something positive and as you know I don’t do this very often, so I am not very good at it :)

This is the way to go.

>> 
>>> +
>>> # 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.
> 
> Where does the symlink then come from on new installations?

It will be part of the regular image like all the other symlinks, too.

-Michael

> 
> Thanks, and best regards,
> Peter Müller
> 
>> 
>> 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