Added a very simply way to backup up capabilities.

[mattihautameki]

Since capabilities are not backuped with tar I implemented a file based backup using getcap and setcap.This commit was tested on SLES12 and RHEL7. Both use capabilities instead of SUID for ping, arping, etc.

[schlomo]

Did you observe this? Better rely on REQUIRED_PROGS and simply assume that it works. And if not then we should urgently fix REQUIRED_PROGS

[gdha]

As you added setcap and getcap to the REQUIRED_PROGS array remove the if which check as it is unneeded (rest assure the test for REQUIRED_PROGS works fine).

[mattihautameki]

In my opinion the REQUIRED_PROGS in prep/default/95_check_missing_programs.sh is not working correctly. Bash is not my favorite thing so maybe I am wrong.
Due to MISSING_PROGS=("") the later test -n "$MISSING_PROGS" always detects the first element as null.

[root@cen2 rear]# MISSING_PROGS=("")
[root@cen2 rear]# MISSING_PROGS=( "${MISSING_PROGS[@]}" "missing_bin" )
[root@cen2 rear]# if test -n "$MISSING_PROGS" ; then echo "something is missing" ;fi

What works for me is

if [ ${#MISSING_PROGS[@]} -ne 1 ] ; then echo "something is missing" ;fi

[schlomo]

Hi @mattihautameki,

thanks a lot for this pull request! This is indeed a missing feature and thanks a lot for providing us with a first implementation.

I went through the code and left some detailed comments. IMHO only the following are real blockers:

• rename BACKUP_CAP
• Use quotes for setcap
• parse the capabilities file in a more robust way, e.g. with this example: while IFS="=" read file cap ; do file="${file% }" cap="${cap# }" ; declare -p file cap ; done <<<'/some file with blanks and " = some_cap,other_cap'

Kind Regards,
Schlomo

[jsmeix]

Regarding #771 (comment) "REQUIRED_PROGS is not working correctly":

Also in my opinion REQUIRED_PROGS is not working correctly, see #755 (comment) and subsequent comments.

But I still do not know under what exact circumstances rear should fail with an error if something in REQUIRED_PROGS is missing so that I cannot decide if REQUIRED_PROGS currently works as intended or not.

[mattihautameki]

Hi!
I implemented the suggested improvments to the best of my belief.

• Changed BACKUP_CAP to NETFS_RESTORE_CAPABILITIES and moved it to the NETFS Section in default.conf.
• Use quotes for filename and capabilities.
• I adapted the MISSING_PROGS check in95_check_missing_programs.sh since the Error function is not called even if all binaries from REQUIRED_PROG are missing.

I also moved the block which is collecting the capabilities 41_save_capabilities.sh to the resuce section of NETFS. This is because /var/lib/rear/recovery/capabilities is not in the ISO from the actual mkbackup-run. When rear mkbackup is run a second the file will be included to the ISO because it is already present on the filesystem.
I am not familiar with the whole code of rear so let me know if there is a better way.

Kind Regards,
Markus

[gdha]

@mattihautameki looks OK to me. Thank you for the new (missing) feature.