adduser/rmuser.perl

   1 #!/usr/bin/perl
   2 # -*- perl -*-
   3 # Copyright 1995, 1996, 1997 Guy Helmer, Ames, Iowa 50014.
   4 # All rights reserved.
   5 #
   6 # Redistribution and use in source and binary forms, with or without
   7 # modification, are permitted provided that the following conditions
   8 # are met:
   9 # 1. Redistributions of source code must retain the above copyright
  10 #    notice, this list of conditions and the following disclaimer as
  11 #    the first lines of this file unmodified.
  12 # 2. Redistributions in binary form must reproduce the above copyright
  13 #    notice, this list of conditions and the following disclaimer in the
  14 #    documentation and/or other materials provided with the distribution.
  15 # 3. The name of the author may not be used to endorse or promote products
  16 #    derived from this software without specific prior written permission.
  17 #
  18 # THIS SOFTWARE IS PROVIDED BY GUY HELMER ``AS IS'' AND ANY EXPRESS OR
  19 # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20 # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21 # IN NO EVENT SHALL GUY HELMER BE LIABLE FOR ANY DIRECT, INDIRECT,
  22 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23 # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27 # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28 #
  29 # rmuser - Perl script to remove users
  30 #
  31 # Guy Helmer <ghelmer@cs.iastate.edu>, 02/23/97
  32 #
  33 #       $Id: rmuser.perl,v 1.6 1997/03/08 18:04:45 wosch Exp $
  34
  35 sub LOCK_SH {0x01;}
  36 sub LOCK_EX {0x02;}
  37 sub LOCK_NB {0x04;}
  38 sub LOCK_UN {0x08;}
  39 sub F_SETFD {2;}
  40
  41 $ENV{"PATH"} = "/bin:/sbin:/usr/bin:/usr/sbin";
  42 umask(022);
  43 $whoami = $0;
  44 $passwd_file = "/etc/master.passwd";
  45 $new_passwd_file = "${passwd_file}.new.$$";
  46 $group_file = "/etc/group";
  47 $new_group_file = "${group_file}.new.$$";
  48 $mail_dir = "/var/mail";
  49 $crontab_dir = "/var/cron/tabs";
  50 $atjob_dir = "/var/at/jobs";
  51 $affirm = 0;
  52
  53 #$debug = 1;
  54
  55 sub cleanup {
  56     local($sig) = @_;
  57
  58     print STDERR "Caught signal SIG$sig -- cleaning up.\n";
  59     &unlockpw;
  60     if (-e $new_passwd_file) {
  61         unlink $new_passwd_file;
  62     }
  63     exit(0);
  64 }
  65
  66 sub lockpw {
  67     # Open the password file for reading
  68     if (!open(MASTER_PW, "$passwd_file")) {
  69         print STDERR "${whoami}: Error: Couldn't open ${passwd_file}: $!\n";
  70         exit(1);
  71     }
  72     # Set the close-on-exec flag just in case
  73     fcntl(MASTER_PW, &F_SETFD, 1);
  74     # Apply an advisory lock the password file
  75     if (!flock(MASTER_PW, &LOCK_EX|&LOCK_NB)) {
  76         print STDERR "${whoami}: Error: Couldn't lock ${passwd_file}: $!\n";
  77         exit(1);
  78     }
  79 }
  80
  81 sub unlockpw {
  82     flock(MASTER_PW, &LOCK_UN);
  83 }
  84
  85 $SIG{'INT'} = 'cleanup';
  86 $SIG{'QUIT'} = 'cleanup';
  87 $SIG{'HUP'} = 'cleanup';
  88 $SIG{'TERM'} = 'cleanup';
  89
  90 if ($#ARGV == 1 && $ARGV[0] eq '-y') {
  91     shift @ARGV;
  92     $affirm = 1;
  93 }
  94
  95 if ($#ARGV > 0) {
  96     print STDERR "usage: ${whoami} [-y] [username]\n";
  97     exit(1);
  98 }
  99
 100 if ($< != 0) {
 101     print STDERR "${whoami}: Error: you must be root to use ${whoami}\n";
 102     exit(1);
 103 }
 104
 105 &lockpw;
 106
 107 if ($#ARGV == 0) {
 108     # Username was given as a parameter
 109     $login_name = pop(@ARGV);
 110     die "Sorry, login name must contain alphanumeric characters only.\n"
 111         if ($login_name !~ /^[a-z0-9_][a-z0-9_\-]*$/);
 112 } else {
 113     if ($affirm) {
 114         print STDERR "${whoami}: Error: -y option given without username!\n";
 115         &unlockpw;
 116         exit 1;
 117     }
 118     # Get the user name from the user
 119     $login_name = &get_login_name;
 120 }
 121
 122 if (($pw_ent = &check_login_name($login_name)) eq '0') {
 123     print STDERR "${whoami}: Error: User ${login_name} not in password database\n";
 124     &unlockpw;
 125     exit 1;
 126 }
 127
 128 ($name, $password, $uid, $gid, $class, $change, $expire, $gecos, $home_dir,
 129  $shell) = split(/:/, $pw_ent);
 130
 131 if ($uid == 0) {
 132     print "${whoami}: Error: I'd rather not remove a user with a uid of 0.\n";
 133     &unlockpw;
 134     exit 1;
 135 }
 136
 137 if (! $affirm) {
 138     print "Matching password entry:\n\n$pw_ent\n\n";
 139
 140     $ans = &get_yn("Is this the entry you wish to remove? ");
 141
 142     if ($ans eq 'N') {
 143         print "${whoami}: Informational: User ${login_name} not removed.\n";
 144         &unlockpw;
 145         exit 0;
 146     }
 147 }
 148
 149 #
 150 # Get owner of user's home directory; don't remove home dir if not
 151 # owned by $login_name
 152
 153 $remove_directory = 1;
 154
 155 if (-l $home_dir) {
 156     $real_home_dir = &resolvelink($home_dir);
 157 } else {
 158     $real_home_dir = $home_dir;
 159 }
 160
 161 #
 162 # If home_dir is a symlink and points to something that isn't a directory,
 163 # or if home_dir is not a symlink and is not a directory, don't remove
 164 # home_dir -- seems like a good thing to do, but probably isn't necessary...
 165
 166 if (((-l $home_dir) && ((-e $real_home_dir) && !(-d $real_home_dir))) ||
 167     (!(-l $home_dir) && !(-d $home_dir))) {
 168     print STDERR "${whoami}: Informational: Home ${home_dir} is not a directory, so it won't be removed\n";
 169     $remove_directory = 0;
 170 }
 171
 172 if (length($real_home_dir) && -d $real_home_dir) {
 173     $dir_owner = (stat($real_home_dir))[4]; # UID
 174     if ($dir_owner != $uid) {
 175         print STDERR "${whoami}: Informational: Home dir ${real_home_dir} is" .
 176             " not owned by ${login_name} (uid ${dir_owner})\n," .
 177                 "\tso it won't be removed\n";
 178         $remove_directory = 0;
 179     }
 180 }
 181
 182 if ($remove_directory && ! $affirm) {
 183     $ans = &get_yn("Remove user's home directory ($home_dir)? ");
 184     if ($ans eq 'N') {
 185         $remove_directory = 0;
 186     }
 187 }
 188
 189 #exit 0 if $debug;
 190
 191 #
 192 # Remove the user's crontab, if there is one
 193 # (probably needs to be done before password databases are updated)
 194
 195 if (-e "$crontab_dir/$login_name") {
 196     print STDERR "Removing user's crontab:";
 197     system('/usr/bin/crontab', '-u', $login_name, '-r');
 198     print STDERR " done.\n";
 199 }
 200
 201 #
 202 # Remove the user's at jobs, if any
 203 # (probably also needs to be done before password databases are updated)
 204
 205 &remove_at_jobs($login_name, $uid);
 206
 207 #
 208 # Kill all the user's processes
 209
 210 &kill_users_processes($login_name, $uid);
 211
 212 #
 213 # Copy master password file to new file less removed user's entry
 214
 215 &update_passwd_file;
 216
 217 #
 218 # Remove the user from all groups in /etc/group
 219
 220 &update_group_file($login_name);
 221
 222 #
 223 # Remove the user's home directory
 224
 225 if ($remove_directory) {
 226     print STDERR "Removing user's home directory ($home_dir):";
 227     &remove_dir($home_dir);
 228     print STDERR " done.\n";
 229 }
 230
 231 #
 232 # Remove files related to the user from the mail directory
 233
 234 #&remove_files_from_dir($mail_dir, $login_name, $uid);
 235 $file = "$mail_dir/$login_name";
 236 if (-e $file || -l $file) {
 237     print STDERR "Removing user's incoming mail file ${file}:";
 238     unlink $file ||
 239         print STDERR "\n${whoami}: Warning: unlink on $file failed ($!) - continuing\n";
 240     print STDERR " done.\n";
 241 }
 242
 243 #
 244 # Remove some pop daemon's leftover file
 245
 246 $file = "$mail_dir/.${login_name}.pop";
 247 if (-e $file || -l $file) {
 248     print STDERR "Removing pop daemon's temporary mail file ${file}:";
 249     unlink $file ||
 250         print STDERR "\n${whoami}: Warning: unlink on $file failed ($!) - continuing\n";
 251     print STDERR " done.\n";
 252 }
 253
 254 #
 255 # Remove files belonging to the user from the directories /tmp, /var/tmp,
 256 # and /var/tmp/vi.recover.  Note that this doesn't take care of the
 257 # problem where a user may have directories or symbolic links in those
 258 # directories -- only regular files are removed.
 259
 260 &remove_files_from_dir('/tmp', $login_name, $uid);
 261 &remove_files_from_dir('/var/tmp', $login_name, $uid);
 262 &remove_files_from_dir('/var/tmp/vi.recover', $login_name, $uid)
 263     if (-e '/var/tmp/vi.recover');
 264
 265 #
 266 # All done!
 267
 268 exit 0;
 269
 270 sub get_login_name {
 271     #
 272     # Get new user's name
 273     local($done, $login_name);
 274
 275     for ($done = 0; ! $done; ) {
 276         print "Enter login name for user to remove: ";
 277         $login_name = <>;
 278         chop $login_name;
 279         if (!($login_name =~ /^[a-z0-9_][a-z0-9_\-]*$/)) {
 280             print STDERR "Sorry, login name must contain alphanumeric characters only.\n";
 281         } elsif (length($login_name) > 16 || length($login_name) == 0) {
 282             print STDERR "Sorry, login name must be 16 characters or less.\n";
 283         } else {
 284             $done = 1;
 285         }
 286     }
 287
 288     print "User name is ${login_name}\n" if $debug;
 289     return($login_name);
 290 }
 291
 292 sub check_login_name {
 293     #
 294     # Check to see whether login name is in password file
 295     local($login_name) = @_;
 296     local($Mname, $Mpassword, $Muid, $Mgid, $Mclass, $Mchange, $Mexpire,
 297           $Mgecos, $Mhome_dir, $Mshell);
 298     local($i);
 299
 300     seek(MASTER_PW, 0, 0);
 301     while ($i = <MASTER_PW>) {
 302         chop $i;
 303         ($Mname, $Mpassword, $Muid, $Mgid, $Mclass, $Mchange, $Mexpire,
 304          $Mgecos, $Mhome_dir, $Mshell) = split(/:/, $i);
 305         if ($Mname eq $login_name) {
 306             seek(MASTER_PW, 0, 0);
 307             return($i);         # User is in password database
 308         }
 309     }
 310     seek(MASTER_PW, 0, 0);
 311
 312     return '0';                 # User wasn't found
 313 }
 314
 315 sub get_yn {
 316     #
 317     # Get a yes or no answer; return 'Y' or 'N'
 318     local($prompt) = @_;
 319     local($done, $ans);
 320
 321     for ($done = 0; ! $done; ) {
 322         print $prompt;
 323         $ans = <>;
 324         chop $ans;
 325         $ans =~ tr/a-z/A-Z/;
 326         if (!($ans =~ /^[YN]/)) {
 327             print STDERR "Please answer (y)es or (n)o.\n";
 328         } else {
 329             $done = 1;
 330         }
 331     }
 332
 333     return(substr($ans, 0, 1));
 334 }
 335
 336 sub update_passwd_file {
 337     local($skipped, $i);
 338
 339     print STDERR "Updating password file,";
 340     seek(MASTER_PW, 0, 0);
 341     open(NEW_PW, ">$new_passwd_file") ||
 342         die "\n${whoami}: Error: Couldn't open file ${new_passwd_file}:\n $!\n";
 343     chmod(0600, $new_passwd_file) ||
 344         print STDERR "\n${whoami}: Warning: couldn't set mode of $new_passwd_file to 0600 ($!)\n\tcontinuing, but please check mode of /etc/master.passwd!\n";
 345     $skipped = 0;
 346     while ($i = <MASTER_PW>) {
 347         if ($i =~ /\n$/) {
 348             chop $i;
 349         }
 350         if ($i ne $pw_ent) {
 351             print NEW_PW "$i\n";
 352         } else {
 353             print STDERR "Dropped entry for $login_name\n" if $debug;
 354             $skipped = 1;
 355         }
 356     }
 357     close(NEW_PW);
 358     seek(MASTER_PW, 0, 0);
 359
 360     if ($skipped == 0) {
 361         print STDERR "\n${whoami}: Whoops! Didn't find ${login_name}'s entry second time around!\n";
 362         unlink($new_passwd_file) ||
 363             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";
 364         &unlockpw;
 365         exit 1;
 366     }
 367
 368     #
 369     # Run pwd_mkdb to install the updated password files and databases
 370
 371     print STDERR " updating databases,";
 372     system('/usr/sbin/pwd_mkdb', '-p', ${new_passwd_file});
 373     print STDERR " done.\n";
 374
 375     close(MASTER_PW);           # Not useful anymore
 376 }
 377
 378 sub update_group_file {
 379     local($login_name) = @_;
 380
 381     local($i, $j, $grmember_list, $new_grent, $changes);
 382     local($grname, $grpass, $grgid, $grmember_list, @grmembers);
 383
 384     $changes = 0;
 385     print STDERR "Updating group file:";
 386     open(GROUP, $group_file) ||
 387         die "\n${whoami}: Error: couldn't open ${group_file}: $!\n";
 388     if (!flock(GROUP, &LOCK_EX|&LOCK_NB)) {
 389         print STDERR "\n${whoami}: Error: couldn't lock ${group_file}: $!\n";
 390         exit 1;
 391     }
 392     local($group_perms, $group_uid, $group_gid) =
 393         (stat(GROUP))[2, 4, 5]; # File Mode, uid, gid
 394     open(NEW_GROUP, ">$new_group_file") ||
 395         die "\n${whoami}: Error: couldn't open ${new_group_file}: $!\n";
 396     chmod($group_perms, $new_group_file) ||
 397         printf STDERR "\n${whoami}: Warning: could not set permissions of new group file to %o ($!)\n\tContinuing, but please check permissions of $group_file!\n", $group_perms;
 398     chown($group_uid, $group_gid, $new_group_file) ||
 399         print STDERR "\n${whoami}: Warning: could not set owner/group of new group file to ${group_uid}/${group_gid} ($!)\n\rContinuing, but please check ownership of $group_file!\n";
 400     while ($i = <GROUP>) {
 401         if (!($i =~ /$login_name/)) {
 402             # Line doesn't contain any references to the user, so just add it
 403             # to the new file
 404             print NEW_GROUP $i;
 405         } else {
 406             #
 407             # Remove the user from the group
 408             if ($i =~ /\n$/) {
 409                 chop $i;
 410             }
 411             ($grname, $grpass, $grgid, $grmember_list) = split(/:/, $i);
 412             @grmembers = split(/,/, $grmember_list);
 413             undef @new_grmembers;
 414             local(@new_grmembers);
 415             foreach $j (@grmembers) {
 416                 if ($j ne $login_name) {
 417                     push(@new_grmembers, $j);
 418                 } else {
 419                     print STDERR " $grname";
 420                     $changes = 1;
 421                 }
 422             }
 423             if ($grname eq $login_name && $#new_grmembers == -1) {
 424                 # Remove a user's personal group if empty
 425                 print STDERR " (removing group $grname -- personal group is empty)";
 426                 $changes = 1;
 427             } else {
 428                 $grmember_list = join(',', @new_grmembers);
 429                 $new_grent = join(':', $grname, $grpass, $grgid, $grmember_list);
 430                 print NEW_GROUP "$new_grent\n";
 431             }
 432         }
 433     }
 434     close(NEW_GROUP);
 435     rename($new_group_file, $group_file) || # Replace old group file with new
 436         die "\n${whoami}: Error: couldn't rename $new_group_file to $group_file ($!)\n";
 437     close(GROUP);                       # File handle is worthless now
 438     print STDERR " (no changes)" if (! $changes);
 439     print STDERR " done.\n";
 440 }
 441
 442 sub remove_dir {
 443     # Remove the user's home directory
 444     local($dir) = @_;
 445     local($linkdir);
 446
 447     if (-l $dir) {
 448         $linkdir = &resolvelink($dir);
 449         # Remove the symbolic link
 450         unlink($dir) ||
 451             warn "${whoami}: Warning: could not unlink symlink $dir: $!\n";
 452         if (!(-e $linkdir)) {
 453             #
 454             # Dangling symlink - just return now
 455             return;
 456         }
 457         # Set dir to be the resolved pathname
 458         $dir = $linkdir;
 459     }
 460     if (!(-d $dir)) {
 461         print STDERR "${whoami}: Warning: $dir is not a directory\n";
 462         unlink($dir) || warn "${whoami}: Warning: could not unlink $dir: $!\n";
 463         return;
 464     }
 465     system('/bin/rm', '-rf', $dir);
 466 }
 467
 468 sub remove_files_from_dir {
 469     local($dir, $login_name, $uid) = @_;
 470     local($path, $i, $owner);
 471
 472     print STDERR "Removing files belonging to ${login_name} from ${dir}:";
 473
 474     if (!opendir(DELDIR, $dir)) {
 475         print STDERR "\n${whoami}: Warning: couldn't open directory ${dir} ($!)\n";
 476         return;
 477     }
 478     while ($i = readdir(DELDIR)) {
 479         next if $i eq '.';
 480         next if $i eq '..';
 481
 482         $owner = (stat("$dir/$i"))[4]; # UID
 483         if ($uid == $owner) {
 484             if (-f "$dir/$i") {
 485                 print STDERR " $i";
 486                 unlink "$dir/$i" ||
 487                     print STDERR "\n${whoami}: Warning: unlink on ${dir}/${i} failed ($!) - continuing\n";
 488             } else {
 489                 print STDERR " ($i not a regular file - skipped)";
 490             }
 491         }
 492     }
 493     closedir(DELDIR);
 494
 495     printf STDERR " done.\n";
 496 }
 497
 498 sub remove_at_jobs {
 499     local($login_name, $uid) = @_;
 500     local($i, $owner, $found);
 501
 502     $found = 0;
 503     opendir(ATDIR, $atjob_dir) || return;
 504     while ($i = readdir(ATDIR)) {
 505         next if $i eq '.';
 506         next if $i eq '..';
 507         next if $i eq '.lockfile';
 508
 509         $owner = (stat("$atjob_dir/$i"))[4]; # UID
 510         if ($uid == $owner) {
 511             if (!$found) {
 512                 print STDERR "Removing user's at jobs:";
 513                 $found = 1;
 514             }
 515             # Use atrm to remove the job
 516             print STDERR " $i";
 517             system('/usr/bin/atrm', $i);
 518         }
 519     }
 520     closedir(ATDIR);
 521     if ($found) {
 522         print STDERR " done.\n";
 523     }
 524 }
 525
 526 sub resolvelink {
 527     local($path) = @_;
 528     local($l);
 529
 530     while (-l $path && -e $path) {
 531         if (!defined($l = readlink($path))) {
 532             die "${whoami}: readlink on $path failed (but it should have worked!): $!\n";
 533         }
 534         if ($l =~ /^\//) {
 535             # Absolute link
 536             $path = $l;
 537         } else {
 538             # Relative link
 539             $path =~ s/\/[^\/]+\/?$/\/$l/; # Replace last component of path
 540         }
 541     }
 542     return $path;
 543 }
 544
 545 sub kill_users_processes {
 546     local($login_name, $uid) = @_;
 547     local($pid, $result);
 548
 549     #
 550     # Do something a little complex: fork a child that changes its
 551     # real and effective UID to that of the removed user, then issues
 552     # a "kill(9, -1)" to kill all processes of the same uid as the sender
 553     # (see kill(2) for details).
 554     # The parent waits for the exit of the child and then returns.
 555
 556     if ($pid = fork) {
 557         # Parent process
 558         waitpid($pid, 0);
 559     } elsif (defined $pid) {
 560         # Child process
 561         $< = $uid;
 562         $> = $uid;
 563         if ($< != $uid || $> != $uid) {
 564             print STDERR "${whoami}: Error (kill_users_processes):\n" .
 565                 "\tCouldn't reset uid/euid to ${uid}: current uid/euid's are $< and $>\n";
 566             exit 1;
 567         }
 568         $result = kill(9, -1);
 569         print STDERR "Killed process(es) belonging to $login_name.\n"
 570             if $result;
 571         exit 0;
 572     } else {
 573         # Couldn't fork!
 574         print STDERR "${whoami}: Error: couldn't fork to kill ${login_name}'s processes - continuing\n";
 575     }
 576 }