mySQL 5.0.11 sources for tomato

[tomato.git] / release / src / router / mysql / mysql-test / lib / v1 / mtr_unique.pl

# -*- cperl -*-
# Copyright (c) 2006 MySQL AB, 2008 Sun Microsystems, Inc.
# Use is subject to license terms.
# 
# 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; version 2 of the License.
# 
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

#
# This file is used from mysql-test-run.pl when choosing
# port numbers and directories to use for running mysqld.
#

use strict;
use Fcntl ':flock';

#
# Requested IDs are stored in a hash and released upon END.
#
my %mtr_unique_assigned_ids = ();
my $mtr_unique_pid;
BEGIN {
        $mtr_unique_pid = $$ unless defined $mtr_unique_pid;
}
END { 
        if($mtr_unique_pid == $$) {
                while(my ($id,$file) = each(%mtr_unique_assigned_ids)) {
                        print "Autoreleasing $file:$id\n";
                        mtr_release_unique_id($file, $id);
                }
        }
}

#
# Require a unique, numerical ID, given a file name (where all
# requested IDs are stored), a minimum and a maximum value.
#
# We use flock to implement locking for the ID file and ignore
# possible problems arising from lack of support for it on 
# some platforms (it should work on most, and the possible
# race condition would occur rarely). The proper solution for
# this is a daemon that manages IDs, of course.
#
# If no unique ID within the specified parameters can be 
# obtained, return undef.
#
sub mtr_require_unique_id($$$) {
        my $file = shift;
        my $min = shift;
        my $max = shift;
        my $ret = undef;
        my $changed = 0;

        my $can_use_ps = `ps -e | grep '^[ ]*$$ '`;

        if(eval("readlink '$file'") || eval("readlink '$file.sem'")) {
                die 'lock file is a symbolic link';
        }

        chmod 0777, "$file.sem";
        open SEM, ">", "$file.sem" or die "can't write to $file.sem";
        flock SEM, LOCK_EX or die "can't lock $file.sem";
        if(! -e $file) {
                open FILE, ">", $file or die "can't create $file";
                close FILE;
        }

        if(eval("readlink '$file'") || eval("readlink '$file.sem'")) {
                die 'lock file is a symbolic link';
        }

        chmod 0777, $file;
        open FILE, "+<", $file or die "can't open $file";
        select undef,undef,undef,0.2;
        seek FILE, 0, 0;
        my %taken = ();
        while(<FILE>) {
                chomp;
                my ($id, $pid) = split / /;
                $taken{$id} = $pid;
                if($can_use_ps) {
                        my $res = `ps -e | grep '^[ ]*$pid '`;
                        if(!$res) {
                                print "Ignoring slot $id used by missing process $pid.\n";
                                delete $taken{$id};
                                ++$changed;
                        }
                }
        }
        for(my $i=$min; $i<=$max; ++$i) {
                if(! exists $taken{$i}) {
                        $ret = $i;
                        $taken{$i} = $$;
                        ++$changed;
                        last;
                }
        }
        if($changed) {
                seek FILE, 0, 0;
                truncate FILE, 0 or die "can't truncate $file";
                for my $k (keys %taken) {
                        print FILE $k . ' ' . $taken{$k} . "\n";
                }
        }
        close FILE;
        flock SEM, LOCK_UN or warn "can't unlock $file.sem";
        close SEM;
        $mtr_unique_assigned_ids{$ret} = $file if defined $ret;
        return $ret;
}

#
# Require a unique ID like above, but sleep if no ID can be
# obtained immediately.
#
sub mtr_require_unique_id_and_wait($$$) {
        my $ret = mtr_require_unique_id($_[0],$_[1],$_[2]);
        while(! defined $ret) {
                sleep 30;
                $ret = mtr_require_unique_id($_[0],$_[1],$_[2]);
                print "Waiting for unique id to become available...\n" unless $ret;
        }
        return $ret;
}

#
# Release a unique ID.
#
sub mtr_release_unique_id($$) {
        my $file = shift;
        my $myid = shift;

        if(eval("readlink '$file'") || eval("readlink '$file.sem'")) {
                die 'lock file is a symbolic link';
        }

        open SEM, ">", "$file.sem" or die "can't write to $file.sem";
        flock SEM, LOCK_EX or die "can't lock $file.sem";

        if(eval("readlink '$file'") || eval("readlink '$file.sem'")) {
                die 'lock file is a symbolic link';
        }

        if(! -e $file) {
                open FILE, ">", $file or die "can't create $file";
                close FILE;
        }
        open FILE, "+<", $file or die "can't open $file";
        select undef,undef,undef,0.2;
        seek FILE, 0, 0;
        my %taken = ();
        while(<FILE>) {
                chomp;
                my ($id, $pid) = split / /;
                $taken{$id} = $pid;
        }
        delete $taken{$myid};
        seek FILE, 0, 0;
        truncate FILE, 0 or die "can't truncate $file";
        for my $k (keys %taken) {
                print FILE $k . ' ' . $taken{$k} . "\n";
        }
        close FILE;
        flock SEM, LOCK_UN or warn "can't unlock $file.sem";
        close SEM;
        delete $mtr_unique_assigned_ids{$myid};
}

1;