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#!/usr/bin/perl
# -*- perl -*-
# Copyright 1995, 1996 Guy Helmer, Madison, South Dakota 57042.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer as
# the first lines of this file unmodified.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY GUY HELMER ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL GUY HELMER BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# rmuser - Perl script to remove users
#
# Guy Helmer <ghelmer@alpha.dsu.edu>, 07/17/96
#
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# $Id$
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sub LOCK_SH {0x01;}
sub LOCK_EX {0x02;}
sub LOCK_NB {0x04;}
sub LOCK_UN {0x08;}
sub F_SETFD {2;}
$ENV{"PATH"} = "/bin:/sbin:/usr/bin:/usr/sbin";
umask(022);
$whoami = $0;
$passwd_file = "/etc/master.passwd";
$new_passwd_file = "${passwd_file}.new.$$";
$group_file = "/etc/group";
$new_group_file = "${group_file}.new.$$";
$mail_dir = "/var/mail";
$crontab_dir = "/var/cron/tabs";
$atjob_dir = "/var/at/jobs";
#$debug = 1;
sub cleanup {
local($sig) = @_;
print STDERR "Caught signal SIG$sig -- cleaning up.\n";
&unlockpw;
if (-e $new_passwd_file) {
unlink $new_passwd_file;
}
exit(0);
}
sub lockpw {
# Open the password file for reading
if (!open(MASTER_PW, "$passwd_file")) {
print STDERR "${whoami}: Error: Couldn't open ${passwd_file}: $!\n";
exit(1);
}
# Set the close-on-exec flag just in case
fcntl(MASTER_PW, &F_SETFD, 1);
# Apply an advisory lock the password file
if (!flock(MASTER_PW, &LOCK_EX|&LOCK_NB)) {
print STDERR "Couldn't lock ${passwd_file}: $!\n";
exit(1);
}
}
sub unlockpw {
flock(MASTER_PW, &LOCK_UN);
}
$SIG{'INT'} = 'cleanup';
$SIG{'QUIT'} = 'cleanup';
$SIG{'HUP'} = 'cleanup';
$SIG{'TERM'} = 'cleanup';
if ($#ARGV > 0) {
print STDERR "usage: ${whoami} [username]\n";
exit(1);
}
if ($< != 0) {
print STDERR "${whoami}: Error: you must be root to use ${whoami}\n";
exit(1);
}
&lockpw;
if ($#ARGV == 0) {
# Username was given as a parameter
$login_name = pop(@ARGV);
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die "Sorry, login name must contain alphanumeric characters only.\n"
if ($login_name !~ /^[a-z0-9_][a-z0-9_\-]*$/);
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} else {
# Get the user name from the user
$login_name = &get_login_name;
}
if (($pw_ent = &check_login_name($login_name)) eq '0') {
print STDERR "${whoami}: Error: User ${login_name} not in password database\n";
&unlockpw;
exit 1;
}
($name, $password, $uid, $gid, $class, $change, $expire, $gecos, $home_dir,
$shell) = split(/:/, $pw_ent);
if ($uid == 0) {
print "${whoami}: Sorry, I'd rather not remove a user with a uid of 0.\n";
&unlockpw;
exit 1;
}
print "Matching password entry:\n\n$pw_ent\n\n";
$ans = &get_yn("Is this the entry you wish to remove? ");
if ($ans eq 'N') {
print "User ${login_name} not removed.\n";
&unlockpw;
exit 0;
}
#
# Get owner of user's home directory; don't remove home dir if not
# owned by $login_name
$remove_directory = 1;
if (-l $home_dir) {
$real_home_dir = &resolvelink($home_dir);
} else {
$real_home_dir = $home_dir;
}
#
# If home_dir is a symlink and points to something that isn't a directory,
# or if home_dir is not a symlink and is not a directory, don't remove
# home_dir -- seems like a good thing to do, but probably isn't necessary...
if (((-l $home_dir) && ((-e $real_home_dir) && !(-d $real_home_dir))) ||
(!(-l $home_dir) && !(-d $home_dir))) {
print STDERR "${whoami}: Home ${home_dir} is not a directory, so it won't be removed\n";
$remove_directory = 0;
}
if (length($real_home_dir) && -d $real_home_dir) {
$dir_owner = (stat($real_home_dir))[4]; # UID
if ($dir_owner != $uid) {
print STDERR "${whoami}: Home dir ${real_home_dir} is not owned by ${login_name} (uid ${dir_owner})\n";
$remove_directory = 0;
}
}
if ($remove_directory) {
$ans = &get_yn("Remove user's home directory ($home_dir)? ");
if ($ans eq 'N') {
$remove_directory = 0;
}
}
#exit 0 if $debug;
#
# Remove the user's crontab, if there is one
# (probably needs to be done before password databases are updated)
if (-e "$crontab_dir/$login_name") {
print STDERR "Removing user's crontab:";
system('/usr/bin/crontab', '-u', $login_name, '-r');
print STDERR " done.\n";
}
#
# Remove the user's at jobs, if any
# (probably also needs to be done before password databases are updated)
&remove_at_jobs($login_name, $uid);
#
# Copy master password file to new file less removed user's entry
&update_passwd_file;
#
# Remove the user from all groups in /etc/group
&update_group_file($login_name);
#
# Remove the user's home directory
if ($remove_directory) {
print STDERR "Removing user's home directory ($home_dir):";
&remove_dir($home_dir);
print STDERR " done.\n";
}
#
# Remove the user's incoming mail file
if (-e "$mail_dir/$login_name" || -l "$mail_dir/$login_name") {
print STDERR "Removing user's incoming mail file ($mail_dir/$login_name):";
unlink "$mail_dir/$login_name" ||
print STDERR "\n${whoami}: warning: unlink on $mail_dir/$login_name failed ($!) - continuing\n";
print STDERR " done.\n";
}
#
# All done!
exit 0;
sub get_login_name {
#
# Get new user's name
local($done, $login_name);
for ($done = 0; ! $done; ) {
print "Enter login name for user to remove: ";
$login_name = <>;
chop $login_name;
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if (!($login_name =~ /^[a-z0-9_][a-z0-9_\-]*$/)) {
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print STDERR "Sorry, login name must contain alphanumeric characters only.\n";
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} elsif (length($login_name) > 16 || length($login_name) == 0) {
print STDERR "Sorry, login name must be 16 characters or less.\n";
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} else {
$done = 1;
}
}
print "User name is ${login_name}\n" if $debug;
return($login_name);
}
sub check_login_name {
#
# Check to see whether login name is in password file
local($login_name) = @_;
local($Mname, $Mpassword, $Muid, $Mgid, $Mclass, $Mchange, $Mexpire,
$Mgecos, $Mhome_dir, $Mshell);
local($i);
seek(MASTER_PW, 0, 0);
while ($i = <MASTER_PW>) {
chop $i;
($Mname, $Mpassword, $Muid, $Mgid, $Mclass, $Mchange, $Mexpire,
$Mgecos, $Mhome_dir, $Mshell) = split(/:/, $i);
if ($Mname eq $login_name) {
seek(MASTER_PW, 0, 0);
return($i); # User is in password database
}
}
seek(MASTER_PW, 0, 0);
return '0'; # User wasn't found
}
sub get_yn {
#
# Get a yes or no answer; return 'Y' or 'N'
local($prompt) = @_;
local($done, $ans);
for ($done = 0; ! $done; ) {
print $prompt;
$ans = <>;
chop $ans;
$ans =~ tr/a-z/A-Z/;
if (!($ans =~ /^[YN]/)) {
print STDERR "Please answer (y)es or (n)o.\n";
} else {
$done = 1;
}
}
return(substr($ans, 0, 1));
}
sub update_passwd_file {
local($skipped, $i);
print STDERR "Updating password file,";
seek(MASTER_PW, 0, 0);
open(NEW_PW, ">$new_passwd_file") ||
die "\n${whoami}: Error: Couldn't open file ${new_passwd_file}:\n $!\n";
chmod(0600, $new_passwd_file) ||
print STDERR "\n${whoami}: warning: couldn't set mode of $new_passwd_file to 0600 ($!)\n\tcontinuing, but please check mode of /etc/master.passwd!\n";
$skipped = 0;
while ($i = <MASTER_PW>) {
if ($i =~ /\n$/) {
chop $i;
}
if ($i ne $pw_ent) {
print NEW_PW "$i\n";
} else {
print STDERR "Dropped entry for $login_name\n" if $debug;
$skipped = 1;
}
}
close(NEW_PW);
seek(MASTER_PW, 0, 0);
if ($skipped == 0) {
print STDERR "\n${whoami}: Whoops! Didn't find ${login_name}'s entry second time around!\n";
unlink($new_passwd_file) ||
print STDERR "\n${whoami}: warning: couldn't unlink $new_passwd_file ($!)\n\tPlease investigate, as this file should not be left in the filesystem\n";
&unlockpw;
exit 1;
}
#
# Run pwd_mkdb to install the updated password files and databases
print STDERR " updating databases,";
system('/usr/sbin/pwd_mkdb', '-p', ${new_passwd_file});
print STDERR " done.\n";
close(MASTER_PW); # Not useful anymore
}
sub update_group_file {
local($login_name) = @_;
local($i, $j, $grmember_list, $new_grent);
local($grname, $grpass, $grgid, $grmember_list, @grmembers);
print STDERR "Updating group file:";
open(GROUP, $group_file) ||
die "\n${whoami}: Error: couldn't open ${group_file}: $!\n";
if (!flock(GROUP, &LOCK_EX|&LOCK_NB)) {
print STDERR "\n${whoami}: Error: couldn't lock ${group_file}: $!\n";
exit 1;
}
local($group_perms, $group_uid, $group_gid) =
(stat(GROUP))[2, 4, 5]; # File Mode, uid, gid
open(NEW_GROUP, ">$new_group_file") ||
die "\n${whoami}: Error: couldn't open ${new_group_file}: $!\n";
chmod($group_perms, $new_group_file) ||
printf STDERR "\n${whoami}: warning: could not set permissions of new group file to %o ($!)\n\tContinuing, but please check permissions of $group_file!\n", $group_perms;
chown($group_uid, $group_gid, $new_group_file) ||
print STDERR "\n${whoami}: warning: could not set owner/group of new group file to ${group_uid}/${group_gid} ($!)\n\rContinuing, but please check ownership of $group_file!\n";
while ($i = <GROUP>) {
if (!($i =~ /$login_name/)) {
# Line doesn't contain any references to the user, so just add it
# to the new file
print NEW_GROUP $i;
} else {
#
# Remove the user from the group
if ($i =~ /\n$/) {
chop $i;
}
($grname, $grpass, $grgid, $grmember_list) = split(/:/, $i);
@grmembers = split(/,/, $grmember_list);
undef @new_grmembers;
local(@new_grmembers);
foreach $j (@grmembers) {
if ($j ne $login_name) {
push(new_grmembers, $j);
} elsif ($debug) {
print STDERR "Removing $login_name from group $grname\n";
}
}
if ($grname eq $login_name && $#new_grmembers == -1) {
# Remove a user's personal group if empty
print STDERR "Removing group $grname -- personal group is empty\n";
} else {
$grmember_list = join(',', @new_grmembers);
$new_grent = join(':', $grname, $grpass, $grgid, $grmember_list);
print NEW_GROUP "$new_grent\n";
}
}
}
close(NEW_GROUP);
rename($new_group_file, $group_file) || # Replace old group file with new
die "\n${whoami}: error: couldn't rename $new_group_file to $group_file ($!)\n";
close(GROUP); # File handle is worthless now
print STDERR " done.\n";
}
sub remove_dir {
# Remove the user's home directory
local($dir) = @_;
local($linkdir);
if (-l $dir) {
$linkdir = &resolvelink($dir);
# Remove the symbolic link
unlink($dir) ||
warn "${whoami}: Warning: could not unlink symlink $dir: $!\n";
if (!(-e $linkdir)) {
#
# Dangling symlink - just return now
return;
}
# Set dir to be the resolved pathname
$dir = $linkdir;
}
if (!(-d $dir)) {
print STDERR "${whoami}: Warning: $dir is not a directory\n";
unlink($dir) || warn "${whoami}: Warning: could not unlink $dir: $!\n";
return;
}
system('/bin/rm', '-rf', $dir);
}
sub remove_at_jobs {
local($login_name, $uid) = @_;
local($i, $owner, $found);
$found = 0;
opendir(ATDIR, $atjob_dir) || return;
while ($i = readdir(ATDIR)) {
next if $i eq '.';
next if $i eq '..';
next if $i eq '.lockfile';
$owner = (stat("$atjob_dir/$i"))[4]; # UID
if ($uid == $owner) {
if (!$found) {
print STDERR "Removing user's at jobs:";
$found = 1;
}
# Use atrm to remove the job
print STDERR " $i";
system('/usr/bin/atrm', $i);
}
}
closedir(ATDIR);
if ($found) {
print STDERR " done.\n";
}
}
sub resolvelink {
local($path) = @_;
local($l);
while (-l $path && -e $path) {
if (!defined($l = readlink($path))) {
die "${whoami}: readlink on $path failed (but it should have worked!): $!\n";
}
if ($l =~ /^\//) {
# Absolute link
$path = $l;
} else {
# Relative link
$path =~ s/\/[^\/]+\/?$/\/$l/; # Replace last component of path
}
}
return $path;
}
