#3500 PR merged: In sbin/rear error out if '-c' is used in recovery system

Labels: enhancement, fixed / solved / done

jsmeix opened issue at 2025-07-30 14:55:

I tested it on my SLES15-SP6 test VM in a Git clone.

On the original test system VM:

# usr/sbin/rear -D -c /foor/bar mkbackup
ERROR: The '-c' option argument '/foor/bar' is not a directory

# mkdir /etc/myrear

# cp -av etc/rear/* /etc/myrear
'etc/rear/local.conf' -> '/etc/myrear/local.conf'

# usr/sbin/rear -D -c /etc/myrear mkbackup
Relax-and-Recover 2.9 / 2025-01-31
Running rear mkbackup (PID 3681 date 2025-07-30 16:43:01)
Command line options: usr/sbin/rear -D -c /etc/myrear mkbackup
Using config directory '/etc/myrear'
...

In the ReaR recovery system on a replacement VM:

RESCUE localhost:~ # rear -D -c /etc/myrear recover
ERROR: The '-c' option is not supported within the ReaR rescue/recovery system (its config directory is always /etc/rear)

RESCUE localhost:~ # find / -xdev | grep myrear
[no output]

RESCUE localhost:~ # rear -D recover
...

The recovery "just worked" for me
and the recreated system boots and works normally.

  • Description of the changes in this pull request:

In sbin/rear error out
when '-c' is used inside the ReaR recovery system
because the '-c' option is not supported within
the ReaR recovery system because
its config directory is always /etc/rear

jsmeix commented at 2025-07-31 12:40:

@rear/contributors
I would like to merge it tomorrow (Friday) afternoon
unless there are objections.

jsmeix commented at 2025-07-31 13:10:

@schlomo
I was already wondering how to deal with portable mode
when I developed the changes for this pull request
(which was the most time consuming part of this pull request)
because I have no practical experience with portable mode
and I don't know how it should behave in practice.

So I followed what the existing code
which sets RECOVERY_MODE tells:

# PORTABLE mode is meant to be used only to run 'rear recover' within a foreign rescue system,
# see https://github.com/rear/rear/pull/3206#issuecomment-2122173021
if test -e "/etc/rear-release" || test "$PORTABLE" ; then
    RECOVERY_MODE=1
fi

Because "rear recover" does not work with '-c'
(see my comment in this pull request code)
also '-c' cannot work for what portable mode
is meant to be used.

I had a look how portable mode makes its ReaR tar archive
in output/PORTABLE/default/450_create_portable_archive.sh
and at first glance it seems there is nothing special
which would include an alternative config directory
so I concluded '-c' can also not work in portable mode
because also in portable mode there is only etc/rear

schlomo commented at 2025-07-31 13:14:

@jsmeix yes, I agree. Let's leave it as you wrote it.

jsmeix commented at 2025-08-01 09:59:

The current implementation does a hardcoded error exit
when '-c /config/dir' is used within the ReaR recovery system
even when /config/dir exists within the ReaR recovery system
because the user had specified to get it included via

COPY_AS_IS+=( /config/dir )

So I investigated what could be done here.

I tested with my above SLES15-SP6 test VMs
how things are in the ReaR recovery system with

COPY_AS_IS+=( /etc/myrear/ )

In the ReaR recovery system this results:

RESCUE localhost:~ # find /etc/rear    
/etc/rear
/etc/rear/mappings
/etc/rear/mappings/mac
/etc/rear/os.conf
/etc/rear/local.conf
/etc/rear/rescue.conf

RESCUE localhost:~ # find /etc/myrear
/etc/myrear
/etc/myrear/local.conf

So certain additional config files are missing
(mappings/mac os.conf rescue.conf)
when '-c /etc/myrear' is used within the ReaR recovery system.

I tried nevertheless rear -c /etc/myrear recover
(with modified /bin/rear to not error out)
and in my simple test case it even finished
without an explicit error.

BUT
in general we cannot know how far or if at all

# rear -c /alternative/config/dir recover

will work because only /etc/rear/ contains all config files
which are normally expected and used by "rear recover".

Therefore the '-c' option is not supported
within the ReaR recovery system because therein
the only supported config directory is /etc/rear/

Nevertheless the user can specify

COPY_AS_IS+=( /alternative/config/dir )

but then he must manually setup things properly within
his ReaR recovery system before calling "rear recover"
i.e. he must provide the right config files in /etc/rear/

lzaoral commented at 2025-08-20 14:05:

Unfortunately, a2fe977d3cac54e1dcdad49146f822217c2b83d1 broke parsing of workflow arguments, e.g. rear format -- -y /dev/sda no longer works:

# rear format -- /dev/sdb
ERROR: Argument 'format' not accepted. Use 'rear format -- --help' for more information.

The format argument gets passed to the workflow as well which was not the case before.

[Export of Github issue for rear/rear.]