UNIX for Dummies Questions & Answers

#!/u/bin/perl
#    This is a script to add users to the passwd / shadow files.  It
# prompts for a first name, middle inital and last name.  A username
# is generated from the first inital, middle inital, and lastname.
# This username can be changed.  After a username has been selected
# the passwd file is scaned to see if the user already exists.  If the
# username exists then the user is prompted to change the username.
#   Once a valid username is chosen, the passwd file is scaned to find
# the next free userid.  This userid must be greater than the $minuid
# variable.  The entry is added to the passwd and shadow files, the
# home direcrory is created and 'make passwd' is done.
#
# $Revision: 1.5 $

#!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
# These values are changable.  Set them to the configuration
#  of enviroment.

#This is the NIS domain name.
chomp ($domain = `/bin/domainname`);

# This file contains a log of the accounts and passwords for the 
# created users.  Look here for the passwords.
$PASSWD_FILE="/var/nis/bin/PASS.OUT";

# This is the shell to give the user
$shell="/bin/ksh";

# This is the location of the homedir.  This is where to make it.
# the homedir passwd entry is set to /home/$username
$homedir='/toast1/home/home/';

# The location of the source files.
$NISfiles="/var/nis/$domain/masters";

# This is the salt used when crypting the password
$SALT="qtzjk24s1";

# Command to make the passwd files
$MAKE = "cd /var/nis/$domain ; /u/bin/make passwd";

# location of the cvs (version control system) executable
$CVS = "/u/bin/cvs -n";

#default location of CVS
$CVSROOT = "/adm/cvs/cvsroot";

#First UID to start with
$FIRST_UID = 1500;



#!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

###############################################################
# let the coding begin
###############################################################

BEGIN {
        print ("\n\nNIS account creation utility\n\n\n");
}

#Check and make sure everything is cool with CVS before we start
#&check_cvs if ( -f $CVS);


# reads passwd file and assigns it to PASS file handle.  
# takes each line in PASS filehandle and assigns each line to an individual
# element in array passwd.

open PASS, "<$NISfiles/passwd" or die "can't open $NISfiles/passwd";
while (<PASS>) {

        chomp;

        #skip comments and whitespace
        next if (/^\s*#/ or /^\s*$/);

        # get the fields in the passwd entry
        ($uname,$x,$uid,$gid,$gecos,$home,$shell)  = split ':', $_;

        # trying to be careful
        if ($uname eq "") { die "ERROR: bad line in passwd:\n$_\n\n" }

        # check for duplicate uids and unames
        if ( $passwd {$uid} ) {
                die "ERROR: duplicate entries for UID $uid \n$passwd{$uid} \n$_ 
\nPlease correct error before using adduser.\n\n";

        } elsif ($uname2uid {$uname}) {
                die "ERROR: duplicate entries for $uname \n $passwd{$uname2uid{$
uname}} \n $_ \nPlease correct this error before using adduser.\n\n";
        }

        # key the passwd list on uid. used to sort the file by uid
        $passwd {$uid} = $_;

        # store an indexed list of unames used to detect duplicate unames
        $uname2uid {$uname} = $uid;

}
close PASS;

open SHADOW, "<$NISfiles/shadow" or die "can't open shadow in $NISfiles";
while (<SHADOW>) {

        chomp;

        # skip comments and whitespace
        next if (/^\s*#/ or /^\s*$/);

        # get the fields in the shadow entry
        ($uname) = split /:/, $_;

        # die if no passwd entry exists for uname 
        unless ( $uname2uid {$uname}) 
                { die "ERROR: User $uname exists in shadow but not in passwd fil
e.\nPlease correct this error before using adduser.\n\n" }

        # key the shadow list on uid by converting uname to uid
        $uid = $uname2uid {$uname};

        # error if uid not in passwd file
        unless ($uid) {
            die "ERROR: user $uname in shadow but not in passwd.  This error may
 also be caused by having a valid passwd entry with uid equal to zero.  This pro
gram does not support uid = 0 since it was designed for use with NIS.\nPlease co
rrect this error.\n\n";
        }

        # check for duplicate shadow entries
        if ($shadow {$uid})
            { die "ERROR: duplicate shadow entry for $uname\n$shadow{$uid}\n$_\n
\n" }

        # finally store the shadow entry in a hash ordered by username.
        $shadow {$uname2uid {$uname}} = $_;
}
close SHADOW;

# check for users in passwd but not in shadow
for $uid (keys %passwd) {

    unless ($shadow {$uid}) 
        { die "This user is missing a shadow entry:\n$passwd{$uid}" }

}

#init rand number generator
srand(time|$$);

########################
### Begin Loop that allows mutiple accounts to be added at once
#########

do {


#prompt administrator for user information

&read_new_user();

# Ask if name is correct and check username. If mk_unique_user results
# False then root decided not to create this user. 

 if(&mk_unique_user) {

    # Pick a initial password.

    $rvalue = int(rand(1000));
    ($uhead) = ( $name[0] =~ /^(.{1,4})/ );
    $nv = join('',$uhead,$rvalue);
    $pwd = crypt($nv,$SALT);
    
    # scan the passwd list for the first unused uid
    for ($uid = $FIRST_UID; $passwd{$uid}; ++$uid) {} 

    # choose group for new user
    &choose_group();

    # add user info to passwd map file
 
    $passwd {$uid} ="$username:x:$uid:$gid:@name:/home/$username:$shell";
    $uname2uid {$username} = $uid;

    # add user info to the shadow map file
    $shadow {$uid} = $username . ":" . $pwd . ":::::::";
 
    # save the new passwd file
    &save_pass;

    # create home dir
    &build_dir;

    # save the new passwd file
    &output_info;

  }

 # Ask if more users are to be added

  do {
    print "\nAdd another User (y or n)?";
    chop($confirm = <STDIN>);
    $confirm =~ tr/YN/yn/;
  } while (($confirm ne "y" )&&( $confirm ne "n") &&( $confirm ne ""));
} while ( $confirm eq "y");

### End of loop for users
 

### Make the NIS database
&build_database;

#end of main -------------------------


#------------------------------------------------------------------ 
# BUILD_DIR: Create the directory for the new user
sub build_dir {
    my $userhome;
    print "Creating user's home directory\n";
    $userhome = join '', $homedir, $username;
    system ("mkdir", $userhome);
    system ("cp /etc/skel/local.profile $userhome/.profile");
    system ("chown -R $uid:$gid $userhome");
    print "\n";
}

#------------------------------------------------------------------
# MK_UNIQUE_USER: Search the passwd database for user
#                 prompts for new username if name is not unique
sub mk_unique_user {
  my ($i,$confirm, $puser, $unique);
  my ($line); #line of passwd

  #confirm username
  do {
    print "Allow \"@name\" as \"$username\"  (y or n)";
    chop($confirm = <STDIN>);
  } while (($confirm ne "y" )&&( $confirm ne "n") &&( $confirm ne ""));
  if (($confirm eq "n") || ($username eq "")) {
    do {
      do {
         print "(s)kip this entry or (c)hange username: ";
         chop($confirm = <STDIN>);
      } while (($confirm ne "s" )&&( $confirm ne "c"));
      if ($confirm eq "s") 
         { return 0; } #skip this user
       print "Enter new username: ";
       chop($username = <STDIN>);
       print "Confirm \"@name\" as \"$username\" (y or n)";
       chop($confirm = <STDIN>);
     } while (($username ne "")  && ($confirm ne 'y') && ($confirm ne ""));
  }

  #find duplicate usernames 
  # continue looping until $username is not in the uname2uid list
  while ($uname2uid {$username}) {

        # print the conflict
        print "$username requested for @name but found in:\n$passwd{$uname2uid {
$username}}\n";
        # ask if we should not create an account or change the username
        do {
          print "(s)kip account creation or (c)hange username: ";
          chop($confirm = <STDIN>);
        } while (($confirm ne "s" )&&( $confirm ne "c"));


        # skip this account and exit the function
        return 0 if ($confirm eq "s");

        do {

           #get a new username
           print "Enter new username: ";
           chop($username = <STDIN>);

           #confirm the new name
           print "Confirm \"@name\" as \"$username\"  (y or n)";
           chop($confirm = <STDIN>);

        } while (($confirm ne 'y') && ($confirm ne ""));

  } 

  return 1; #do this user
}


#------------------------------------------------------------------ 
# BUILD_DATABASE: Build yp maps
sub build_database 
{
  print "Building password database... \n";
  system( $MAKE ) == 0 
    or die "failed to Make password database";
}

#------------------------------------------------------------------ 
# OUTPUT_INFO: Output new passwd information
sub output_info 
{
    # make a backup copy of the passwd file
    rename("$NISfiles/passwd", "$NISfiles/passwd.old") || die "can't move passwd
";

    # write the new passwd file
    open PASSWD,">$NISfiles/passwd" or die "ERROR: can't write new passwd: $!\n"
;
    for (sort keys %passwd) 
        { print PASSWD $passwd{$_}, "\n" }
    close PASSWD;
        
    # make a backup copy of the shadow file
    rename("$NISfiles/shadow", "$NISfiles/shadow.old") || die "can't move $NISfi
les/shadow to $NISfiles/shadow.old: $!";

    # write the new shadow file
    open(SHADOW,">$NISfiles/shadow") or die "ERROR: can't write new shadow: $!\n
";
    for (sort keys %shadow) 
        { print SHADOW $shadow{$_}, "\n" }
    close SHADOW;       
}


# This saves the username and password from the newly created account
#--------------------------------------------------------------------
sub save_pass 
{
  open(OUTPUT,">>$PASSWD_FILE");
  print OUTPUT "*************************** ";
  print OUTPUT (scalar localtime),"\n\n";
  printf(OUTPUT " NAME: %20s %20s %20s \n\n",$name[0],$name[1],$name[2]);
  printf(OUTPUT " Your username is %15s \n",$username);
  printf(OUTPUT " Your password is %15s \n\n",$nv);
  print OUTPUT "After you login change your password with passwd \n\n";
  print OUTPUT "*************************************************************\n"
;
  close(OUTPUT);
}


#--------------------------------------------------------------------
# read_user_name -- read the user info from the keyboard
#--------------------------------------------------------------------
sub read_new_user
{
        print "Enter user's first name: ";
        $name[0] = <STDIN>;
        chop ($name[0]);
        print "\nEnter user's middle initial: ";
        $name[1] = <STDIN>;
        chop ($name[1]);
        print "\nEnter user's last name: ";
        $name[2] = <STDIN>;
        chop ($name[2]);
        print "\n";

        ($firstinital) = ($name[0] =~ /^(.)/);
        ($middleinital) = ($name[1] =~ /^(.)/);
        $lastname = $name[2] ;

        #create a username from first inital, middle inital, and last name
        $username = join ("",$firstinital,$middleinital,$lastname);

        # change username to lowercase
        $username =~ tr/A-Z/a-z/;

}




#--------------------------------------------------------------------
# choose_group -- prompt for the user's group membership
#--------------------------------------------------------------------
sub choose_group
{
    # by using list context, we read the group file quickly
    open GROUP, "<$NISfiles/group" or die "can't open group file in $NISfiles"; 
    @good_group = <GROUP>;
    close GROUP;
    print "-------------------------------------------\n"; 
    for $group (@good_group) {
        @line = split ':', $group;
        print $line[2], "\t", $line[0], "\n";
    }
    print "-------------------------------------------\n";
    print "what group should the user be in\n";
    $gid = <STDIN>;
    chop ($gid);
}


#--------------------------------------------------------------------
# Checks CVS to see if the files are up to date and etc.
# not in use yet -- cbmasters
#--------------------------------------------------------------------
sub save_pass_cvs 
{
    my $quit = 0;
    my ($USER, %CVS_stat);

    # check if the USER or LOGNAME enviromental variable is set
    # if they are not set then set them.  This works since make and cvs
    # will inherit this enviroment when they are forked later

    unless ($ENV{LOGNAME} or $ENV{USER}) {
        print <<EOF
For CVS to properly update, you must set LOGNAME or USER
to your username.  Please enter you login name now.
USER=EOF

    # read the username from stdin
    $USER = <STDIN>;

    # set the variables
    $ENV{USER} = $USER; $ENV{LOGNAME} = $USER;

    # check for CVSROOT and it is NOT defined then 
    # set it to the default from $CVSROOT
    if ($ENV{CVSROOT})
        { $CVSROOT = $ENV{CVSROOT} }
    else 
        {
        $ENV{CVSROOT}= $CVSROOT;
        print "WARNING: CVSROOT was not defined, so I set it to $CVSROOT\n";
    }

    # The next set of steps check to see if the files under CVS control
    # are up to date.  

    # run a status on the nis files
    open CVS, "$CVS -Q status $NISfiles/passwd $NISfiles/shadow" or die "can't d
o $CVS status $NISfiles/passwd $NISfiles/shadow because $!";

    while (<CVS>) {
        #skip lines not about status
        next unless /^File:/;

        #save the Status of the passwd & shadow
        $CVS_stat{passwd} = $1 if /passwd\s*Status:\s*(\S+)/;
        $CVS_stat{shadow} = $1 if /shadow\s*Status:\s*(\S+)/;

    }
    close CVS;

    #check if status was detected
    unless ($CVS_stat{shadow} and  $CVS_stat{passwd}) {
        print "$CVS -Q status did not return status for passwd and shadow";
        exit -1;
    }

    # let the user know the status
    print "$NISfiles/passwd is $CVS_stat{passwd}\n$NISfiles/shadow is $CVS_stat{
shadow}\n";

    #if the files are not up to do the update them

    if ($CVS_stat{passwd} ne "Up-to-date" or ($CVS_stat{shadow} ne "Up-to-date")
 {
    print <<EOF
One of the files was not up to date, please run the following command

#$CVS update $CVS_stat{passwd} $NISfiles/shadow

You might need this:

#USER=$USER; export $USER; CVSROOT = $CVSROOT; export $CVSROOT
EOF
        
    }

}
## end of file ##