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Diffstat (limited to 'mysql-test/lib/mtr_unique.pl')
| -rw-r--r-- | mysql-test/lib/mtr_unique.pl | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/mysql-test/lib/mtr_unique.pl b/mysql-test/lib/mtr_unique.pl new file mode 100644 index 00000000000..9bf86e26f4f --- /dev/null +++ b/mysql-test/lib/mtr_unique.pl @@ -0,0 +1,119 @@ +# +# 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 = (); +END { + 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($$$) { + my $file = shift; + my $min = shift; + my $max = shift; + my $ret = undef; + + chmod 0777, "$file.sem"; + open SEM, ">", "$file.sem" or die "can't write to $file.sem"; + flock SEM, LOCK_EX or die "can't lock $file.sem"; + if(! -e $file) { + open FILE, ">", $file or die "can't create $file"; + close FILE; + } + chmod 0777, $file; + open FILE, "+<", $file or die "can't open $file"; + select undef,undef,undef,0.2; + seek FILE, 0, 0; + my %taken = (); + while(<FILE>) { + chomp; + my ($id, $pid) = split / /; + $taken{$id} = $pid; + } + seek FILE, 0, 2; + for(my $i=$min; $i<=$max; ++$i) { + if(! exists $taken{$i}) { + print FILE "$i $$\n"; + $ret = $i; + last; + } + } + 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($$$) { + my $ret = mtr_require_unique_id($_[0],$_[1],$_[2]); + while(! defined $ret) { + sleep 10; + $ret = mtr_require_unique_id($_[0],$_[1],$_[2]); + } + return $ret; +} + +# +# Release a unique ID. +# +sub mtr_release_unique_id($$) { + my $file = shift; + my $myid = shift; + + open SEM, ">", "$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; + } + 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; + |