piped program in sendmail's /etc/aliases

Question

I'm trying some sort of auto-subscription via a homegrown script. I know it can be achieved by mailing lists such as Mailman but I also want to learn at the same time on how to do it by hand.

Here's the simple script:

#!/usr/bin/perl

use strict;
use warnings;

open ("RCV_MAIL", ">>/home/icasimpan/mail_received.txt") or die $!;
while(<STDIN>){
   print RCV_MAIL;
}
close(RCV_MAIL);

I attached the above script in /etc/aliases using the syntax:

subscribe: | /home/icasimpan/parse-subscribe.pl

and run

$ sudo newaliases

It's still a very bare script. Just testing out if I my syntax in /etc/aliases is correct.

But when I tried emailing [email protected], it returns something like:

Delivery failure 69

I'm using Lotus Notes so my google search directed me to this link. Apparently, something to do with the file...Not sure.

The command is executable, in fact I tried making it 777 and even created the mail_received.txt in the directory just to ensure I have no file permission problem but still the same.

Answer 1

If you're running a sendmail with smrsh set up (common in a lot of default configurations) you will need to run the piped command out of /etc/smrsh/. It can either be a symlink or a copy of the script, but if sendmail has 'smrsh' defined, it will need to be run from that directory. For example:

subscribe: | /etc/smrsh/parse-subscribe.pl

Check the sendmail documentation on smrsh for more details.

Answer 2

You need to quote the "alias" if it has a space in it:

subscribe: "| /home/icasimpan/parse-subscribe.pl"

or remove the space:

subscribe: |/home/icasimpan/parse-subscribe.pl

Answer 3

open ("RCV_MAIL", ">>/home/icasimpan/mail_received.txt") or die $!;
while(<STDIN>){
   print RCV_MAIL;
}

is wrong.

If you're trying to print lines from STDIN to mail_received.txt, you would need:

open (RCV_MAIL, ">>/home/icasimpan/mail_received.txt") or die $!;
while (<STDIN>) {
   print RCV_MAIL $_;
}

because print with one argument takes the argument to mean the list to print, not the filehandle to print it to.

$ perldoc -f print
print FILEHANDLE LIST
print LIST
...

Also, no need for quotes around the filehandle name in open. Just use RCV_MAIL.