(perl/bash) tar czvf|openssl enc and exit_code status

kamil_maciejewski · 02-19-2009, 02:40 AM

Well, I'm not experienced in BASH/PERL programming, sometimes I make some changes in the backup script. It compresses the data on a tape drive, check is everything done ok and sends a report via email. As it was earlier:

Code:

$exit_code=system("$tar czvf $tapedevice $oracle 1>$tar_status 2>$tar_errors");

and then

Code:

if ((stat($tar_errors))[7] && $exit_code)

checks wheater all is ok or not, click link to see all the code
Perl pastebin - collaborative debugging tool

Lately I added encryption for some more security

Code:

$exit_code=system("tar czvpf $tapedevice $oracle $samba $config $src $webdav | openssl enc -aes-256-cbc -salt -pass file:/tmp/.key 1>$tar_status2 2>$tar_errors2");

copy works, encryption too, but the report always says it's ok, even when it's not
Does anyone know how to check exit code so it would work with tar | openssl.

This is the full script (the part doing compression and encryption):
Perl pastebin - collaborative debugging tool

chrism01 · 02-20-2009, 06:25 AM

If you're going to use system() that way, be aware that it returns the exit value of the system() cmd itself ie whether it ran ok or not. Nothing to do with the exit code(s) of the binaries you call in there.
What you would do is ensure you remove the error file before calling system() then stat the error file to see if it exists. If it does, you had an error, which you can get by reading the error file.

More sophisticated approaches inc using IPC::Open2.pm (http://perldoc.perl.org/IPC/Open2.html) or IPC::Open3.pm (http://perldoc.perl.org/IPC/Open3.html), or using Perl modules that deal direct with tar/ssl etc.
See search.cpan.org for modules.