root/tags/omega-1.0.0-rc3/engine/ispcp_common_methods.pl

#!/usr/bin/perl

# ispCP ω (OMEGA) a Virtual Hosting Control Panel
# Copyright (c) 2001-2006 by moleSoftware GmbH
# http://www.molesoftware.com
# Copyright (c) 2006-2007 by isp Control Panel
# http://isp-control.net
#
#
# License:
#    This program is free software; you can redistribute it and/or
#    modify it under the terms of the MPL Mozilla Public License
#    as published by the Free Software Foundation; either version 1.1
#    of the License, 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
#    MPL Mozilla Public License for more details.
#
#    You may have received a copy of the MPL Mozilla Public License
#    along with this program.
#
#    An on-line copy of the MPL Mozilla Public License can be found
#    http://www.mozilla.org/MPL/MPL-1.1.html
#
#
# The ispCP ω Home Page is at:
#
#    http://isp-control.net
#

BEGIN {

    my @needed = (strict,
                  warnings,
                  IO::Socket,
                  DBI,
                  DBD::mysql,
                  MIME::Entity,
                  MIME::Parser,
                  Crypt::CBC,
                  Crypt::Blowfish,
                  Crypt::PasswdMD5,
                  MIME::Base64,
                  Term::ReadPassword,
                  File::Basename,
                  File::Path);

    my ($mod, $mod_err, $mod_missing) = ('', '_off_', '');

    for $mod (@needed) {

        if (eval "require $mod") {

            $mod -> import();

        } else {

            print STDERR "\nCRITICAL ERROR: Module [$mod] WAS NOT FOUND !\n" ;

            $mod_err = '_on_';

            if ($mod_missing eq '') {

                $mod_missing .= $mod;

            } else {

                $mod_missing .= ", $mod";

            }
        }

    }

    if ($mod_err eq '_on_') {

        print STDERR "\nModules [$mod_missing] WAS NOT FOUND in your system...\n";

        exit 1;

    } else {

        $| = 1;

    }
}

# Global variables;

$main::cc_stdout = '/tmp/ispcp-cc.stdout';

$main::cc_stderr = '/tmp/ispcp-cc.stderr';

$main::el_sep = "\t#\t";

@main::el = ();

%main::domain_id_name = ();

%main::domain_name_id = ();

%main::domain_id_ipid = ();

%main::sub_id_name = ();

%main::sub_name_id = ();

%main::sub_id_parentid = ();

%main::als_id_name = ();

%main::als_name_id = ();

%main::als_id_parentid = ();

%main::ip_id_num = ();

%main::ip_num_id = ();

$main::db_host = undef;

$main::db_user = undef;

$main::db_pwd = undef;

$main::db_name = undef;

@main::db_connect = ();

$main::db = undef;

$main::master_name = 'ispcp-rqst-mngr';

%main::cfg = ();

%main::cfg_reg = ();

$main::cfg_re = '^[ \t]*([\_A-Za-z0-9]+) *= *([^\n\r]*)[\n\r]';

# License request function must not SIGPIPE;

$SIG{PIPE} = 'IGNORE';

$SIG{HUP} = 'IGNORE';

sub push_el {

    my ($el, $sub_name, $msg) = @_;

    push @$el, "$sub_name".$main::el_sep."$msg";

    if (defined($main::engine_debug)) {

        print STDOUT "DEBUG: push_el() sub_name: $sub_name, msg: $msg\n";

    }


}

sub pop_el {

    my ($el) = @_;

    my $data = pop @$el;

    if (!defined($data)) {

        if (defined($main::engine_debug)) {

            print STDOUT "DEBUG: pop_el() Empty 'EL' Stack !\n";

        }

        return undef;
    }

    my ($sub_name, $msg) = split(/$main::el_sep/, $data);

    if (defined($main::engine_debug)) {

        print STDOUT "DEBUG: pop_el() sub_name: $sub_name, msg: $msg\n";

    }


    return $data;

}


sub dump_el {

    my ($el, $fname) = @_;

    my $res;

    if ($fname ne 'stdout' && $fname ne 'stderr') {

        $res = open(FP, ">", $fname);

        if (!defined($res)) {

            return 0;

        }

    }

    my $el_data = undef;

    while (defined($el_data = pop_el(\@main::el))) {

        my ($sub_name, $msg) = split(/$main::el_sep/, $el_data);

        if ($fname eq 'stdout') {

            printf STDOUT "%-30s | %s\n",  $sub_name, $msg;

        } elsif ($fname eq 'stderr') {

            printf STDERR "%-30s | %s\n",  $sub_name, $msg;

        } else {

            printf FP "%-30s | %s\n",  $sub_name, $msg;

        }

    }

    close(FP);

}

sub doSQL {

    my ($sql) = @_;

    my $qr = undef;

    push_el(\@main::el, 'doSQL()', 'Starting...');

    if (!defined($sql) || ($sql eq '')) {

        push_el(\@main::el, 'doSQL()', 'ERROR: Undefined SQL query !');

        return (-1, '');

    }

    if (!defined($main::db) || !ref($main::db)) {

        $main::db = DBI -> connect(@main::db_connect, {PrintError => 0});

        if ( !defined($main::db) ) {

            push_el(
                    \@main::el,
                    'doSQL()',
                    'ERROR: Unable to connect SQL server !'
                   );

            return (-1, '');

        }
    }

    if ($sql =~ /select/i) {

        $qr = $main::db -> selectall_arrayref($sql);

    } elsif ($sql =~ /show/i) {

        $qr = $main::db -> selectall_arrayref($sql);

    } else {

        $qr = $main::db -> do($sql);

    }

    if (defined($qr)) {

        push_el(\@main::el, 'doSQL()', 'Ending...');

        return (0, $qr);

    } else {

        push_el(\@main::el, 'doSQL()', 'ERROR: Incorrect SQL Query -> '.$main::db -> errstr);

        return (-1, '');

    }

}

sub doHashSQL {

    my ($sql) = @_;

    my $qr = undef;

    push_el(\@main::el, 'doHashSQL()', 'Starting...');

    if (!defined($sql) || ($sql eq '')) {

        push_el(\@main::el, 'doHashSQL()', 'ERROR: Undefined SQL query !');

        return (-1, '');

    }

    if (!defined($main::db) || !ref($main::db)) {

        $main::db = DBI -> connect(@main::db_connect, {PrintError => 0});

        if ( !defined($main::db) ) {

            push_el(
                    \@main::el,
                    'doHashSQL()',
                    'ERROR: Unable to connect SQL server !'
                   );

            return (-1, '');

        }
    }

    if ($sql =~ /select/i) {

        $qr = $main::db -> selectall_hashref($sql);

    } elsif ($sql =~ /show/i) {

        $qr = $main::db -> selectall_hashref($sql);

    } else {

        $qr = $main::db -> do($sql);

    }

    if (defined($qr)) {

        push_el(\@main::el, 'doHashSQL()', 'Ending...');

        return (0, $qr);

    } else {

        push_el(\@main::el, 'doHashSQL()', 'ERROR: Incorrect SQL Query -> '.$main::db -> errstr);

        return (-1, '');

    }

}

sub setfmode {

    my ($fname, $fuid, $fgid, $fperms) = @_;

    push_el(\@main::el, 'setfmode()', 'Starting...');

    if (
        !defined($fname) || !defined($fuid) ||
        !defined($fgid) || !defined($fperms) ||
        $fname eq '' || $fuid eq '' ||
        $fgid eq '' || $fperms eq ''
       )
    {

        push_el(
                \@main::el,
                'setfmode()',
                "ERROR: Undefined input data, fname: |$fname|, fuid: |$fuid|, fgid: |$fgid|, fperms: |$fperms| !"
               );

        return -1;

    }

    if (! -e $fname) {

        push_el(
                \@main::el,
                'setfmode()',
                "ERROR: File '$fname' does not exist !"
               );

        return -1;
    }

    my @udata = ();

    my @gdata = ();

    my ($uid, $gid) = ($fuid, $fgid);

        if ($fuid =~ /^\d+$/) {

                $uid = $fuid;

    } elsif ($fuid ne '-1') {

        @udata = getpwnam($fuid);

        if (scalar(@udata) == 0) {

            push_el(
                    \@main::el,
                    'setfmode()',
                    "ERROR: Unknown user '$fuid' !"
                   );

            return -1;

        }

        $uid = $udata[2];
    }

        if ($fgid =~ /^\d+$/) {

                $gid = $fgid;

        } elsif ($fgid ne '-1') {

        @gdata = getgrnam($fgid);

        if (scalar(@gdata) == 0) {

            push_el(
                    \@main::el,
                    'setfmode()',
                    "ERROR: Unknown group '$fgid' !"
                   );

            return -1;

        }

        $gid = $gdata[2];
    }

    my $res = chmod ($fperms, $fname);

    if ($res != 1) {

        push_el(
                \@main::el,
                'setfmode()',
                "ERROR: Can not change permissions of file '$fname' !"
               );

        return -1;

    }

    $res = chown ($uid, $gid, $fname);

    if ($res != 1) {

        push_el(
                \@main::el,
                'setfmode()',
                "ERROR: Can not change user/group of file '$fname' !"
               );

        return -1;

    }

    push_el(\@main::el, 'setfmode()', 'Ending...');

    return 0;

}

sub get_file {

    my ($fname) = @_;

    push_el(\@main::el, 'get_file()', 'Starting...');

    if (!defined($fname) || ($fname eq '')) {

        push_el(
                \@main::el,
                'get_file()',
                "ERROR: Undefined input data, fname: |$fname| !"
               );

        return (-1, '');

    }

    if (! -e $fname) {

        push_el(
                \@main::el,
                'get_file()',
                "ERROR: File '$fname' does not exist !"
               );

        return (-1, '');

    }

    my $res = open(F, '<', $fname);

    if (!defined($res)) {

        push_el(
                \@main::el,
                'get_file()',
                "ERROR: Can't open '$fname' for reading !"
               );

        return (-1, '');

    }

    my @fdata = <F>;

    close(F);

    my $line = join('', @fdata);

    push_el(\@main::el, 'get_file()', 'Ending...');

    return (0, $line);

}

sub store_file {

    my ($fname, $fdata, $fuid, $fgid, $fperms) = @_;

    push_el(\@main::el, 'store_file()', 'Starting...');

    if (
        !defined($fname) || !defined($fuid) ||
        !defined($fgid) || !defined($fperms) ||
        $fname eq '' || $fuid eq '' ||
        $fgid eq '' || $fperms eq ''
       )
    {
        push_el(
                \@main::el,
                'store_file()',
                "ERROR: Undefined input data, fname: |$fname|, fdata, fuid: '$fuid', fgid: '$fgid', fperms: '$fperms'"
               );

        return -1;
    }

    my $res = open(F, '>', $fname);

    if (!defined($res)) {

        push_el(
                \@main::el,
                'store_file()',
                "ERROR: Can't open file |$fname| for writing !"
               );

        return -1;

    }

    print F $fdata;

    close(F);

    my ($rs, $rdata) = setfmode($fname, $fuid, $fgid, $fperms);

    return -1 if ($rs != 0);

    push_el(\@main::el, 'store_file()', 'Ending...');

    return 0;

}

sub save_file {

    my ($fname, $fdata) = @_;

    push_el(\@main::el, 'save_file()', 'Starting...');

    if ( !defined($fname) || $fname eq '' ) {
        push_el(
                \@main::el,
                'save_file()',
                "ERROR: Undefined input data, fname: |$fname|, fdata"
               );

        return -1;
    }

    my $res = open(F, '>', $fname);

    if (!defined($res)) {

        push_el(
                \@main::el,
                'save_file()',
                "ERROR: Can't open file |$fname| for writing !"
               );

        return -1;

    }

    print F $fdata;

    close(F);

    push_el(\@main::el, 'save_file()', 'Ending...');

    return 0;

}

sub del_file {

    my ($fname) = @_;

    push_el(\@main::el, 'del_file()', 'Starting...');

    if (!defined($fname) || ($fname eq '')) {

        push_el(
                \@main::el,
                'del_file()',
                "ERROR: Undefined input data, fname: |$fname| !"
               );

        return -1;

    }

    if (! -e $fname) {

        push_el(
                \@main::el,
                'del_file()',
                "ERROR: File '$fname' does not exist !"
               );

        return -1;

    }

    my $res = unlink ($fname);

    if ($res != 1) {

        push_el(
                \@main::el,
                'del_file()',
                "ERROR: Can't unlink '$fname' !"
               );

        return -1;

    }

    push_el(\@main::el, 'del_file()', 'Ending...');

    return 0;

}

sub set_zone {
    my ($fdata, $data, $zone, $comment) = @_;

    my @fdata = split("\n", $fdata);

    my $bz = '';
    my $az = '';
    my $zs = 0;
    my $ze = 0;
    my $ll;
    my $curline;

    while(length($fdata) > 0) {
        $ll = index($fdata, "\n");
        if( $ll < 0 ) {
            $ll = length( $fdata );
        } else {
            $ll++;
        }
        $curline = substr( $fdata, 0, $ll );
        $fdata = substr( $fdata, $ll );

        if( $zs == 0 ) {
            if( index($curline, $comment."## START ISPCP ".$zone." ###") == 0 ) {
                $zs = 1;
            } else {
                $bz .= $curline;
            }
        } elsif( $ze == 0 ) {
            if( index($curline, $comment."## END ISPCP ".$zone." ###") == 0) {
                $ze = 1;
            }
        } elsif( $ze == 1 ) {
                $az .= $curline;
        }
    }

    return
        $bz.($zs == 1 ? "" : "\n").
        $comment."## START ISPCP ".$zone." ###\n".
        $data."\n".
        $comment."## END ISPCP ".$zone." ###\n".
        $az;
}

sub get_zone {
    my ($fdata, $zone, $comment) = @_;

    my @fdata = split("\n", $fdata);

    my $zonecontent = '';
    my $zs = 0;
    my $ze = 0;
    my $ll;
    my $curline;

    while(length($fdata) > 0) {
        $ll = index($fdata, "\n");
        if( $ll < 0 ) {
            $ll = length( $fdata );
        } else {
            $ll++;
        }
        $curline = substr( $fdata, 0, $ll );
        $fdata = substr( $fdata, $ll );

        if( $zs == 0 ) {
            if( index($curline, $comment."## START ISPCP ".$zone." ###") == 0 ) {
                $zs = 1;
            }
        } elsif( $ze == 0 ) {
            if( index($curline, $comment."## END ISPCP ".$zone." ###") == 0) {
                $ze = 1;
            } else {
                $zonecontent .= $curline;
            }
        }
    }

    return $zonecontent;
}

sub del_zone {
    my ($fdata, $zone, $comment) = @_;

    my @fdata = split("\n", $fdata);

    my $bz = '';
    my $az = '';
    my $zs = 0;
    my $ze = 0;
    my $ll;
    my $curline;

    while(length($fdata) > 0) {
        $ll = index($fdata, "\n");
        if( $ll < 0 ) {
            $ll = length( $fdata );
        } else {
            $ll++;
        }
        $curline = substr( $fdata, 0, $ll );
        $fdata = substr( $fdata, $ll );

        if( $zs == 0 ) {
            if( index($curline, $comment."## START ISPCP ".$zone." ###") == 0 ) {
                $zs = 1;
            } else {
                $bz .= $curline;
            }
        } elsif( $ze == 0 ) {
            if( index($curline, $comment."## END ISPCP ".$zone." ###") == 0) {
                $ze = 1;
            }
        } elsif( $ze == 1 ) {
                $az .= $curline;
        }
    }

    return $bz.$az;
}

sub sys_command {

    my ($cmd) = @_;

    push_el(\@main::el, 'sys_command()', 'Starting...');

    my $result = system($cmd);

    my $exit_value  = $? >> 8;

    my $signal_num  = $? & 127;

    my $dumped_core = $? & 128;

    if ($exit_value == 0) {

        push_el(\@main::el, "sys_command('$cmd')", 'Ending...');

        return 0;

    } else {

        push_el(\@main::el, 'sys_command()', "ERROR: External command '$cmd' returned '$exit_value' status !");

        return -1;

    }

}

sub sys_command_rs {

    my ($cmd) = @_;

    push_el(\@main::el, 'sys_command_rs()', 'Starting...');

    my $result = system($cmd);

    my $exit_value  = $? >> 8;

    my $signal_num  = $? & 127;

    my $dumped_core = $? & 128;

    push_el(\@main::el, 'sys_command_rs()', 'Ending...');

    if ($exit_value == 0) {

        return 0;

    } else {

        return $exit_value;

    }

}

sub make_dir {

    my ($dname, $duid, $dgid, $dperms) = @_;

    my ($rs, $rdata) = ('', '');

    push_el(\@main::el, 'make_dir()', 'Starting...');

    if (
        !defined($dname) || !defined($duid) ||
        !defined($dgid) || !defined($dperms) ||
        $dname eq '' || $duid eq '' ||
        $dgid eq '' || $dperms eq ''
       )
    {

        push_el(\@main::el, 'make_dir()', "ERROR: Undefined input data, dname: |$dname|, duid: |$duid|, dgid: |$dgid|, dperms: |$dperms| !");

        return -1;

    }

    if ( -e $dname && -f $dname ) {

        push_el(\@main::el,'make_dir()', "'$dname' exists as file ! removing file first...");

        return -1 if (del_file($dname) != 0);

    }

    if (!(-e $dname && -d $dname)) {

        push_el(\@main::el, 'make_dir()', "'$dname' doesn't exists as directory! creating...");

        $rs =  mkpath($dname);

        if (!$rs) {

            push_el(\@main::el, 'make_dir()', "ERROR: mkdir() returned '$rs' status !");

            return -1;

        }

    } else {

        push_el(\@main::el, 'make_dir()', "'$dname' exists ! Setting its permissions...");

    }

    return -1 if (setfmode($dname, $duid, $dgid, $dperms) != 0);

    push_el(\@main::el, 'make_dir()', 'Ending...');

    return 0;
}

sub del_dir {

    my ($dname) = @_;

    push_el(\@main::el, 'make_dir()', 'Starting...');

    if (!defined($dname) || ($dname eq '')) {

        push_el(\@main::el, 'make_dir()', "ERROR: Undefined input data, dname: |$dname| !");

        return -1;

    }

    push_el(\@main::el, 'make_dir()', "Trying to remove '$dname'...");

    return -1 if (sys_command("rm -rf $dname") != 0);

    push_el(\@main::el, 'make_dir()', 'Ending...');

    return 0;

}

sub gen_rand_num {

    my ($len) = @_;

    push_el(\@main::el, 'gen_rand_num()', 'Starting...');

    if (!defined($len) || ($len eq '')) {

        push_el(\@main::el, 'gen_rand_num()', "ERROR: Undefined input data, len: |$len| !");

        return (-1, '');

    }

    if (!(0 < $len && $len < 11)) {

        push_el(\@main::el, 'gen_rand_num()', "ERROR: Input data length '$len' out of limits [1, 10] !");

        return (-1, '');

    }

    my @rand_data = ('A'..'Z', 'a'..'z', '0'..'9', '.', '/');

    my ($i, $rdata) = ('', '');

    for ($i = 0; $i < $len; $i++) {

        $rdata .= $rand_data[ rand() * ($#rand_data + 1) ];

    }

    push_el(\@main::el, 'gen_rand_num()', 'Ending...');

    return (0, $rdata);

}

sub gen_sys_rand_num {

    my ($len) = @_;

    push_el(\@main::el, 'gen_sys_rand_num()', 'Starting...');

    if (!defined($len) || ($len eq '')) {

        push_el(\@main::el, 'gen_sys_rand_num()', "ERROR: Undefined input data, len: |$len| !");

        return (-1, '');

    }

    if (0 >= $len ) {

        push_el(\@main::el, 'gen_sys_rand_num()', "ERROR: Input data length '$len' is zero or negative !");

        return (-1, '');

    }

    my $pool_size = 0;
    my $read_avail = 0;

    if ( -e '/proc/sys/kernel/random/entropy_avail') {

        $read_avail = 1;

        $pool_size = int(get_file('/proc/sys/kernel/random/entropy_avail'));

        if ( $pool_size <= ($len + 10)) {
            push_el(\@main::el, 'gen_sys_rand_num()', "WARNING: entropy pool is $pool_size, but we require more or less $len");
        }
    }

    if ( -e '/dev/urandom') {
        push_el(\@main::el, 'gen_sys_rand_num()', "NOTICE: seeding the entropy pool (possible current size: $pool_size)");

        my $seed = $len;
        while ($seed >= 0 ||
              ($read_avail && int(get_file('/proc/sys/kernel/random/entropy_avail')) <= ($len + 10))) {

            my ($n, $c, $l) = (100, undef, 0);

            do {
                $l = int(rand() * 100);
                next if ($l < 0 || $l > 255);
                $c .= chr($l);
            } while($n--);

            save_file('/dev/urandom', $c . (rand() * rand() * rand() * rand()));
            save_file('/dev/urandom', time ^ ($$ + ($$ << 15)) << (1 ^ rand -$$ ));
            $seed--;
        }
    }

    if ($read_avail) {

        $pool_size = int(get_file('/proc/sys/kernel/random/entropy_avail'));

        push_el(\@main::el, 'gen_sys_rand_num()', "NOTICE: new entropy pool size is $pool_size");
    }

    my $rs = open(F, '<', '/dev/random');

    if (!defined($rs)) {

        $rs = open(F, '<', '/dev/urandom');

        if (!defined($rs)) {

            push_el(\@main::el, 'gen_sys_rand_num()', "ERROR: Couldn't open the pseudo-random characters generator");

            return (-1, '');
        }

    }

    my ($i, $rdata, $rc, $rci) = (0, undef, undef, undef);

    while ($i <= $len) {

        read(F, $rc, 1);

        $rci = ord($rc);

        # Excludes all chars below Space (incl.) and bove }, the escape char (\) and the '
        next if ($rci <= 32 || $rci >= 126 || $rci == 92 || $rci == 39);

        $rdata .= $rc;
        $rc = undef;
        $i++;

    }

    close(F);

    push_el(\@main::el, 'gen_sys_rand_num()', 'Ending...');

    return (0, $rdata);

}

sub crypt_md5_data {

    my ($data) = @_;

    push_el(\@main::el, 'crypt_md5_data()', 'Starting...');

    if (!defined($data) || $data eq '') {

        push_el(\@main::el, 'crypt_md5_data()', "ERROR: Undefined input data, data: |$data| !");

        return (-1, '');

    }

    my ($rs, $rdata) = gen_rand_num(2);

    return (-1, '') if ($rs != 0);

    $rdata = unix_md5_crypt($data, $rdata);

    push_el(\@main::el, 'crypt_md5_data()', 'Ending...');

    return (0, $rdata);

}

sub crypt_data {

    my ($data) = @_;

    push_el(\@main::el, 'crypt_data()', 'Starting...');

    if (!defined($data) || $data eq '') {

        push_el(\@main::el, 'crypt_data()', "ERROR: Undefined input data, data: |$data| !");

        return (-1, '');

    }

    my ($rs, $rdata) = gen_rand_num(2);

    return (-1, '') if ($rs != 0);

    $rdata = crypt($data, $rdata);

    push_el(\@main::el, 'crypt_data()', 'Ending...');

    return (0, $rdata);

}

sub get_tag {

    my ($bt, $et, $src) = @_;

    push_el(\@main::el, 'get_tag()', "Starting...");

    if (
        !defined($bt) || !defined($et) ||
        !defined($src) || $bt eq '' ||
        $et eq '' || $src eq ''
       )
    {

        push_el(\@main::el, 'get_tag()', "ERROR: Undefined intput data, bt: |$bt|, et: |$et|, src !");

        return (-1, '');

    }

    my ($bt_len, $et_len, $src_len) = (
                                       length($bt),
                                       length($et),
                                       length($src)
                                      );

    #
    #return ('_e03_', $main::strerr{'_e03_'})
    #
    #if ($bt_len > $src_len || $et_len > $src_len);
    #

    if ($bt eq $et) {


        # Let's search for ...$tag... ;

        # $bt == $et == $tag ;


        my $tag = $bt;

        my $tag_pos = index($src, $tag);

        if ($tag_pos < 0) {

            push_el(\@main::el, 'get_tag()', "ERROR: '$bt' eq '$et', missing '$bt' in src !");

            return (-4, '');

        } else {

            push_el(\@main::el, 'get_tag()', 'Ending...');

            return (0, $tag);

        }

    } else {

        if ($bt_len + $et_len > $src_len) {

            push_el(\@main::el, 'get_tag()', "ERROR: len($bt) + len($et) > len(src) !");

            return (-1, '');

        }


        # Let's search for ...$bt...$et... ;


        my ($bt_pos, $et_pos) = (index($src, $bt), index($src, $et));

        if ($bt_pos < 0 || $et_pos < 0) {

            push_el(\@main::el, 'get_tag()', "ERROR: '$bt' ne '$et', '$bt' or '$et' missing in src !");

            return (-5, '');

        }

        if ($et_pos < $bt_pos + $bt_len) {

            push_el(\@main::el, 'get_tag()', "ERROR: '$bt' ne '$et', '$et' overlaps '$bt' in src !");

            return (-1, '');

        }

        push_el(\@main::el, 'get_tag()', 'Ending...');

        my $tag_len = $et_pos + $et_len - $bt_pos;

        return (0, substr($src, $bt_pos, $tag_len));

    }

}

sub repl_tag {

    my ($bt, $et, $src, $rwith) = @_;

    push_el(\@main::el, 'repl_tag()', "Starting...");

    if (!defined ($rwith)) {

        push_el(\@main::el, 'repl_tag()', "ERROR: Undefined rwith!");

        return (-1, '');

    }

    my ($rs, $rdata) = get_tag($bt, $et, $src);

    return $rs if ($rs != 0);

    my $tag = $rdata;

    my ($tag_pos, $tag_len) = (index($src, $tag), length($tag));

    if ($rwith eq '') {

        substr($src, $tag_pos, $tag_len, '');

    } else {

        substr($src, $tag_pos, $tag_len, $rwith);

    }

    push_el(\@main::el, 'repl_tag()', "Ending...");

    return (0, $src);
}

sub add_tag {

    my ($bt, $et, $src, $adata) = @_;

    push_el(\@main::el, 'add_tag()', "Starting...");

    if (!defined($adata) || $adata eq '') {

        push_el(\@main::el, 'add_tag()', "ERROR: Undefined input data, adata: |$adata| !");

        return (-1, '');
    }

    my ($rs, $rdata) = get_tag($bt, $et, $src);

    return ($rs, '') if ($rs != 0);

    my $rwith = '';

    if ($bt eq $et) {

        $rwith = "$adata$bt";

    } else {

        $rwith = "$adata$bt$et";

    }

    ($rs, $rdata) = repl_tag($bt, $et, $src, $rwith);

    return (-1, '') if ($rs != 0);

    push_el(\@main::el, 'add_tag()', "Ending...");

    return (0, $rdata);
}

sub del_tag {

    my ($bt, $et, $src) = @_;

    push_el(\@main::el, 'del_tag()', "Starting...");

    my ($rs, $rdata) = get_tag($bt, $et, $src);

    return ($rs, '') if ($rs != 0);

    ($rs, $rdata) = repl_tag($bt, $et, $src, '');

    return (-1, '') if ($rs != 0);

    push_el(\@main::el, 'del_tag()', "Ending...");

    return (0, $rdata);

}

sub get_var {

    my ($var, $src) = @_;

    push_el(\@main::el, 'get_var()', "Starting...");

    my ($rs, $rdata) = get_tag($var, $var, $src);

    return ($rs, '') if ($rs != 0);

    push_el(\@main::el, 'get_var()', "Ending...");

    return (0, $rdata);