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Diffstat (limited to 'mysql-test/lib/v1/mtr_unique.pl')
| -rw-r--r-- | mysql-test/lib/v1/mtr_unique.pl | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/mysql-test/lib/v1/mtr_unique.pl b/mysql-test/lib/v1/mtr_unique.pl new file mode 100644 index 00000000..b9ed9138 --- /dev/null +++ b/mysql-test/lib/v1/mtr_unique.pl @@ -0,0 +1,179 @@ +# -*- 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 02110-1335 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; + |