#! /bin/sh # mkulinks --- create links in /home for user home directories # Copyright (C) 1995 Noah S. Friedman # Author: Noah Friedman # Created: 1995-06-23 # $Id: mkulinks,v 1.6 1996/03/03 22:56:39 friedman Exp $ # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2, or (at your option) # any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, you can either send email to this # program's maintainer or write to: The Free Software Foundation, # Inc.; 59 Temple Place, Suite 330; Boston, MA 02111-1307, USA. # Commentary: # Code: # Name by which this script was invoked. progname=`echo "$0" | sed -e 's/[^\/]*\///g'` # To prevent hairy quoting and escaping later. bq='`' eq="'" usage="Usage: $progname {options} Options are: -D, --debug Enable interative perl debugging. -E, --errors-to-fd FD Direct errors to file descriptor FD. This is for the sake of scripts which run via rsh/csh and cannot redirect flexibly. FD can also be one of ${bq}stdin$eq, ${bq}stdout$eq, or ${bq}stderr$eq. -h, --help You're looking at it. -l, --link-directory DIR Make symlinks in DIR (default: /u) -p, --perl PROG Use PROG as perl interpreter. -r, --remove-non-links Remove any non-symlinks. WARNING: this option will remove files and entire directory hierarchies. -s, --strip-non-user-links Remove symlinks which do not correspond to the name of any user account. -v, --verbose Report file operations. " # Initialize variables. # Don't use `unset' since old bourne shells don't have this command. # Instead, assign them an empty value. debug= PERL=${PERL-perl} MKULINKS_HOMEDIR=/u MKULINKS_STRIP= MKULINKS_RMNONLINKS= MKULINKS_VERBOSE= export MKULINKS_HOMEDIR MKULINKS_STRIP export MKULINKS_RMNONLINKS MKULINKS_VERBOSE # Usage: eval "$getopt"; value=$optarg # or optarg_optional=t; eval "$getopt"; value=$optarg # # This function automatically shifts the positional args as appropriate. # The argument to an option is optional if the variable `optarg_optional' # is non-empty. Otherwise, the argument is required and getopt will cause # the program to exit on an error. optarg_optional is reset to be empty # after every call to getopt. The argument (if any) is stored in the # variable `optarg'. # # Long option syntax is `--foo=bar' or `--foo bar'. 2nd argument # won't get used if first long option syntax was used. # # Note: because of broken bourne shells, using --foo=bar syntax can # actually screw the quoting of args that end with trailing newlines. # Specifically, most shells strip trailing newlines from substituted # output, regardless of quoting. getopt=' { optarg= case "$1" in --*=* ) optarg=`echo "$1" | sed -e "1s/^[^=]*=//"` shift ;; * ) case ${2+set} in set ) optarg="$2" shift shift ;; * ) case "$optarg_optional" in "" ) case "$1" in --*=* ) option=`echo "$1" | sed -e "1s/=.*//;q"` ;; * ) option="$1" ;; esac exec 1>&2 echo "$progname: option $bq$option$eq requires argument." echo "$progname: use $bq--help$eq to list option syntax." exit 1 ;; esac ;; esac ;; esac optarg_optional= }' # Parse command line arguments. # Make sure that all wildcarded options are long enough to be unambiguous. # It's a good idea to document the full long option name in each case. # Long options which take arguments will need a `*' appended to the # canonical name to match the value appended after the `=' character. while : ; do case $# in 0) break ;; esac case "$1" in -D | --debug | --d* ) debug=-d shift ;; -E | --errors-to-fd* | --e* ) eval "$getopt" case "$optarg" in 0 | [Ss][Tt][Dd][Ii][Nn] ) exec 2>&0 ;; 1 | [Ss][Tt][Dd][Oo][Uu][Tt] ) exec 2>&1 ;; 2 | [Ss][Tt][Dd][Ee][Rr][Rr] ) : ;; [3456789] ) eval exec "2>&$optarg" ;; * ) echo "$progname: $optarg: Invalid stderr redirect." 1>&2 exit 1 ;; esac ;; -h | --help | --h* ) echo "$usage" 1>&2 exit 0 ;; -l | --link-directory* | --l* ) eval "$getopt" MKULINKS_HOMEDIR="$optarg" ;; -p | --perl* | --p* ) eval "$getopt" PERL="$optarg" ;; -r | --remove-non-links | --r* ) MKULINKS_RMNONLINKS=t shift ;; -s | --strip-non-user-links | --s* ) MKULINKS_STRIP=t shift ;; -v | --verbose | --v* ) MKULINKS_VERBOSE=t shift ;; -- ) # Stop option processing shift break ;; -? | --* ) case "$1" in --*=* ) arg=`echo "$1" | sed -e 's/=.*//'` ;; * ) arg="$1" ;; esac exec 1>&2 echo "$progname: unknown or ambiguous option $bq$arg$eq" echo "$progname: Use $bq--help$eq for a list of options." exit 1 ;; -??* ) # Split grouped single options into separate args and try again optarg="$1" shift set fnord `echo "x$optarg" | sed -e 's/^x-//;s/\(.\)/-\1 /g'` ${1+"$@"} shift ;; * ) break ;; esac done case "$debug" in -d ) set -x ;; esac MKULINKS_PROGNAME="$progname" export MKULINKS_PROGNAME exec "$PERL" $debug - ${1+"$@"} <<'__EOF__' &main; sub main { # Unbuffer output. select (STDERR); $| = 1; select (STDOUT); $| = 1; $progname = $ENV{'MKULINKS_PROGNAME'}; $tophome = $ENV{'MKULINKS_HOMEDIR'}; &make_top ($tophome); if ($ENV{'MKULINKS_RMNONLINKS'} eq 't') { &prune_directory ($tophome, 0); } undef %homelinks; if ($ENV{'MKULINKS_STRIP'} eq 't') { %homelinks = &getdirentries ($tophome); } %homelinks = &make_links (%homelinks); if ($ENV{'MKULINKS_STRIP'} eq 't') { &remove_non_user_links ($tophome, %homelinks); } } sub make_top { local ($tophome) = @_; if (-e $tophome) { if (! -d $tophome) { &errmsg ($tophome, "File exists and is not a directory."); &errmsg ("Aborting."); exit (1); } } else { &verbose ("Creating", $tophome); if (! mkdir ($tophome, 0777)) { &iferr ("mkdir", $tophome, "$!."); &errmsg ("Aborting."); exit (1); } } } sub getdirentries { local ($dir) = @_; local (@files, %files); if (! opendir (DIRHNDL, $dir)) { &iferr ("opendir", "$dir", "$!."); return %files; } @files = grep (-l, readdir (DIRHNDL)); close (DIRHNDL); foreach $dir (@files) { $files{$dir} = ''; } return %files; } # This function performs the equivalent of an `rm -rf'. # However, if the second arg is 0, it does not remove symlinks. sub prune_directory { local ($dir, $linksp) = @_; local (@files, %files); if (! opendir (DIRHNDL, $dir)) { &iferr ("opendir", "$dir", "$!."); return 0; } @files = grep (!/^\.\.?$/, readdir (DIRHNDL)); close (DIRHNDL); if (! $linksp) { local (@ofiles) = @files; local ($i) = 0; undef (@files); foreach $file (@ofiles) { if (! -l "$dir/$file") { $files[$i] = $file; $i++; } } } foreach $ent (@files) { local ($file) = "$dir/$ent"; if (-d $file) { &prune_directory ($file, 1); &verbose ("Removing", $file, "Directory, not symbolic link."); if (! rmdir ($file)) { &iferr ("rmdir", $file, "$!."); } } else { &verbose ("Removing", $file, "File, not symbolic link."); &unlink1 ($file); } } } sub make_links { local (%homelinks) = @_; local (%processed); while (@pwent = getpwent ()) { local ($user, $pw, $uid, $gid, $quota, $comment, $gcos, $home, $shell) = @pwent; # We avoid processing any account twice. If a user account is # duplicated both in an NIS database and in the local passwd file, # getpwent will eventually return both instances. However, it seems # that the NIS entry is returned first. Regardless, the symlink # created should match the home directory of the user account # normally referenced by other programs, i.e. the first one. if (defined ($processed{$user})) { &verbose ("Ignoring", $user, "Duplicate passwd entry."); next; } $processed{$user} = 1; delete ($homelinks{$user}); if (&invalid_user_p (@pwent)) { &verbose ("Ignoring", $user, "Exempt username."); next; } local ($symlink) = $tophome . "/" . $user; if ($symlink ne $home) { # Don't clobber entry if it's not a symlink already. if (-e $symlink && ! -l $symlink) { &verbose ("Skipping", $user, $symlink, "Not a symbolic link."); next; } local ($linkname) = readlink ($symlink); if (-d $home) { if ($linkname ne $home) { if (-l $symlink) { &verbose ("Updating", "$symlink -> $home"); &unlink1 ($symlink); } else { &verbose ("Creating", "$symlink -> $home"); } if (! symlink ($home, $symlink)) { &iferr ("symlink", "$symlink -> $home", "$!."); } } } else { if (-l $symlink) { # Remove symlink; it doesn't point to anything that exists. &verbose ("Removing", $symlink, "$linkname nonexistent"); &unlink1 ($symlink); } } } } return %homelinks; } sub remove_non_user_links { local ($tophome, %homelinks) = @_; foreach $dir (sort (keys (%homelinks))) { local ($symlink) = $tophome . "/" . $dir; if (-l $symlink) { &verbose ("Deleting", $symlink, "Not a user link."); &unlink1 ($symlink); } } } # Various heuristics to decide if this is a real user account or not. sub invalid_user_p { local ($user, $pw, $uid, $gid, $quota, $comment, $gcos, $home, $shell) = @_; if ($home eq "/") { return 1; } return 0; } sub unlink1 { foreach $file (@_) { if (unlink ($file) != 1) { &iferr ("unlink", $file, "$!."); } } } sub iferr { if ($! != 0) { &errmsg (@_); } } sub errmsg { printf (STDERR join(": ", $progname, @_) . "\n"); } sub verbose { if ("$ENV{MKULINKS_VERBOSE}" eq "t") { printf (STDOUT join(": ", @_) . "\n"); } } __EOF__ # mkulinks ends here