#!/usr/bin/perl

#
# mailall
#
# sends mail to all users on this host.  verifies that the user is really
# a user by checking uid, shell, and login name.  allows us to send mail
# to, for example, "allusers@mother.cs.colorado.edu" and delievers that
# mail to all the "real" people on that machine.
#
# requires a line in /usr/lib/aliases like:
# allusers: "|/usr/local/bin/mailall"
#
# By: davewood@cs.colorado.edu
#     October 15, 1992
#

$MIN_ID = 1000;

#
# first we get a list of legal shells
#

open(SHELLS,"/etc/shells");
@shells = <SHELLS>;
close SHELLS;

#
# now look at all the passwd entries and make a list of "real" usernames
#

open(PASSWD,"/etc/passwd");
foreach (<PASSWD>)
{
	undef $login,$passwd,$uid,$gid,$gcos,$home,$shell;
	($login,$passwd,$uid,$gid,$gcos,$home,$shell) = split(/:/);
	push(@mailto,$login) if ($uid >= $MIN_ID &&
				$login ne "nobody" &&
				(grep(/^$shell$/,@shells) ||
					$shell =~ /^$/) &&
				length($passwd) == 13);
}
close PASSWD;

#
# now shove stdin into a mail message to all these users
#

open (MAIL,"|/usr/lib/sendmail @mailto");
foreach (<STDIN>)
{
	print MAIL;
}
close MAIL;