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Up to [local] / src / usr.sbin / adduser

Fix some warnings and take advantage of perl5 system defines

In adduser, use /etc/ptmp as a lock file like the other passwd programs.
Currently it is just kept empty which is not so great.

Use sysopen() with explicit file modes so there is no race whereby
a user could see the contents on the master.passwd temp file in rmuser.
Fix order of file opens in rmuser so we don't try and remove anything
unless we can lock all our files.

#!/usr/bin/perl
# -*- perl -*-
#
# $OpenBSD: rmuser.perl,v 1.3 2000/11/25 23:22:33 millert Exp $
#
# 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
#
#	$From: rmuser.perl,v 1.2 1996/12/07 21:25:12 ache Exp $

use Fcntl qw(:DEFAULT :flock);

$ENV{"PATH"} = "/bin:/sbin:/usr/bin:/usr/sbin";
umask(022);
$whoami = $0;
$passwd_file = "/etc/master.passwd";
$passwd_tmp = "/etc/ptmp";
$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;

END {
    if (-e $passwd_tmp) {
	unlink($passwd_tmp) ||
	    warn "\n${whoami}: warning: couldn't unlink $passwd_tmp ($!)\n\tPlease investigate, as this file should not be left in the filesystem\n";
    }
}

sub cleanup {
    local($sig) = @_;

    print STDERR "Caught signal SIG$sig -- cleaning up.\n";
    exit(0);
}

sub open_files {
    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;
    }

    sysopen(NEW_PW, $passwd_tmp, O_RDWR|O_CREAT|O_EXCL, 0600) ||
	die "\n${whoami}: Error: Password file busy\n";

    if (!open(MASTER_PW, $passwd_file)) {
	print STDERR "${whoami}: Error: Couldn't open ${passwd_file}: $!\n";
	exit(1);
    }
}

$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);
}

&open_files;

if ($#ARGV == 0) {
    # Username was given as a parameter
    $login_name = pop(@ARGV);
} 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";
    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";
    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";
    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 = <>;
	chomp $login_name;
	if (!($login_name =~ /^\w+$/)) {
	    print STDERR "Sorry, login name must contain alphanumeric characters only.\n";
	} elsif (length($login_name) > 16 || length($login_name) == 0) {
	    print STDERR "Sorry, login name must be 16 characters or less.\n";
	} 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>) {
	chomp $i;
	($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 = <>;
	chomp $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);
    $skipped = 0;
    while ($i = <MASTER_PW>) {
	chomp($i);
	if ($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";
	exit 1;
    }

    #
    # Run pwd_mkdb to install the updated password files and databases

    print STDERR " updating databases,";
    system('/usr/sbin/pwd_mkdb', '-p', ${passwd_tmp});
    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:";
    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
	    chomp $i;
	    ($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;
}