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

["Peter Müller" <peter.mueller@ipfire.org>]

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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...

> 
>> +
>> # 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?

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
>