You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
46 lines
922 B
46 lines
922 B
#!/usr/bin/perl
|
|
eval 'exec /usr/bin/perl -S $0 ${1+"$@"}'
|
|
if $running_under_some_shell;
|
|
|
|
require 'sys/ipc.ph';
|
|
require 'sys/msg.ph';
|
|
|
|
$| = 1;
|
|
|
|
$mode = shift;
|
|
die "usage: ipcmsg {r|s}\n" unless $mode =~ /^[rs]$/;
|
|
$signal = ($mode eq "s");
|
|
|
|
$id = semget(0x1234, 1, ($signal ? 0 : &IPC_CREAT) | 0644);
|
|
die "Can't get semaphore: $!\n" unless defined($id);
|
|
print "semaphore id: $id\n";
|
|
|
|
if ($signal) {
|
|
while (<STDIN>) {
|
|
print "Signalling\n";
|
|
unless (semop($id, pack("sss", 0, 1, 0))) {
|
|
die "Can't signal semaphore: $!\n";
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
$SIG{'INT'} = $SIG{'QUIT'} = "leave";
|
|
for (;;) {
|
|
unless (semop($id, pack("sss", 0, -1, 0))) {
|
|
die "Can't wait for semaphore: $!\n";
|
|
}
|
|
print "Unblocked\n";
|
|
}
|
|
}
|
|
|
|
&leave;
|
|
|
|
sub leave {
|
|
if (!$signal) {
|
|
$x = semctl($id, 0, &IPC_RMID, 0);
|
|
if (!defined($x) || $x < 0) {
|
|
die "Can't remove semaphore: $!\n";
|
|
}
|
|
}
|
|
exit;
|
|
}
|