#!./perl -w

my $child;
my $can_fork;
my $has_perlio;

BEGIN {
    require Config; import Config;
    $can_fork = $Config{'d_fork'} || $Config{'d_pseudofork'};

    if ($^O eq "hpux" or $Config{'extensions'} !~ /\bSocket\b/ &&
        !(($^O eq 'VMS') && $Config{d_socket})) {
	print "1..0\n";
	exit 0;
    }
}

{
    # This was in the BEGIN block, but since Test::More 0.47 added support to
    # detect forking, we don't need to fork before Test::More initialises.

    # Too many things in this test will hang forever if something is wrong,
    # so we need a self destruct timer. And IO can hang despite an alarm.

    if( $can_fork) {
	my $parent = $$;
	$child = fork;
	die "Fork failed" unless defined $child;
	if (!$child) {
	    $SIG{INT} = sub {exit 0}; # You have 60 seconds. Your time starts now.
	    my $must_finish_by = time + 60;
	    my $remaining;
	    while (($remaining = $must_finish_by - time) > 0) {
		sleep $remaining;
	    }
	    warn "Something unexpectedly hung during testing";
	    kill "INT", $parent or die "Kill failed: $!";
	    exit 1;
	}
    }
    unless ($has_perlio = PerlIO::Layer->can("find") && PerlIO::Layer->find('perlio')) {
	print <<EOF;
# Since you don't have perlio you might get failures with UTF-8 locales.
EOF
    }
}

use Socket;
use Test::More;
use strict;
use warnings;
use Errno;

my $skip_reason;

if( !$Config{d_alarm} ) {
    plan skip_all => "alarm() not implemented on this platform";
} elsif( !$can_fork ) {
    plan skip_all => "fork() not implemented on this platform";
} else {
    # This should fail but not die if there is real socketpair
    eval {socketpair LEFT, RIGHT, -1, -1, -1};
    if ($@ =~ /^Unsupported socket function "socketpair" called/ ||
	$! =~ /^The operation requested is not supported./) { # Stratus VOS
	plan skip_all => 'No socketpair (real or emulated)';
    } else {
	eval {AF_UNIX};
	if ($@ =~ /^Your vendor has not defined Socket macro AF_UNIX/) {
	    plan skip_all => 'No AF_UNIX';
	} else {
	    plan tests => 45;
	}
    }
}

# But we'll install an alarm handler in case any of the races below fail.
$SIG{ALRM} = sub {die "Unexpected alarm during testing"};

ok (socketpair (LEFT, RIGHT, AF_UNIX, SOCK_STREAM, PF_UNSPEC),
    "socketpair (LEFT, RIGHT, AF_UNIX, SOCK_STREAM, PF_UNSPEC)")
    or print "# \$\! = $!\n";

if ($has_perlio) {
    binmode(LEFT,  ":bytes");
    binmode(RIGHT, ":bytes");
}

my @left = ("hello ", "world\n");
my @right = ("perl ", "rules!"); # Not like I'm trying to bias any survey here.

foreach (@left) {
    # is (syswrite (LEFT, $_), length $_, "write " . _qq ($_) . " to left");
    is (syswrite (LEFT, $_), length $_, "syswrite to left");
}
foreach (@right) {
    # is (syswrite (RIGHT, $_), length $_, "write " . _qq ($_) . " to right");
    is (syswrite (RIGHT, $_), length $_, "syswrite to right");
}

# stream socket, so our writes will become joined:
my ($buffer, $expect);
$expect = join '', @right;
undef $buffer;
is (read (LEFT, $buffer, length $expect), length $expect, "read on left");
is ($buffer, $expect, "content what we expected?");
$expect = join '', @left;
undef $buffer;
is (read (RIGHT, $buffer, length $expect), length $expect, "read on right");
is ($buffer, $expect, "content what we expected?");

ok (shutdown(LEFT, SHUT_WR), "shutdown left for writing");
# This will hang forever if eof is buggy, and alarm doesn't interrupt system
# Calls. Hence the child process minder.
SKIP: {
    skip "SCO Unixware / OSR have a bug with shutdown",2 if $^O =~ /^(?:svr|sco)/;
    local $SIG{ALRM} = sub { warn "EOF on right took over 3 seconds" };
    local $TODO = "Known problems with unix sockets on $^O"
	if $^O eq 'hpux'   || $^O eq 'super-ux';
    alarm 3;
    $! = 0;
    ok (eof RIGHT, "right is at EOF");
    local $TODO = "Known problems with unix sockets on $^O"
	if $^O eq 'unicos' || $^O eq 'unicosmk';
    is ($!, '', 'and $! should report no error');
    alarm 60;
}

my $err = $!;
$SIG{PIPE} = 'IGNORE';
{
    local $SIG{ALRM} =
	sub { warn "syswrite to left didn't fail within 3 seconds" };
    alarm 3;
    # Split the system call from the is() - is() does IO so
    # (say) a flush may do a seek which on a pipe may disturb errno
    my $ans = syswrite (LEFT, "void");
    $err = $!;
    is ($ans, undef, "syswrite to shutdown left should fail");
    alarm 60;
}
{
    # This may need skipping on some OSes - restoring value saved above
    # should help
    $! = $err;
    ok (($!{EPIPE} or $!{ESHUTDOWN}), '$! should be EPIPE or ESHUTDOWN')
	or printf "\$\!=%d(%s)\n", $err, $err;
}

my @gripping = (chr 255, chr 127);
foreach (@gripping) {
    is (syswrite (RIGHT, $_), length $_, "syswrite to right");
}

ok (!eof LEFT, "left is not at EOF");

$expect = join '', @gripping;
undef $buffer;
is (read (LEFT, $buffer, length $expect), length $expect, "read on left");
is ($buffer, $expect, "content what we expected?");

ok (close LEFT, "close left");
ok (close RIGHT, "close right");


# And now datagrams
# I suspect we also need a self destruct time-bomb for these, as I don't see any
# guarantee that the stack won't drop a UDP packet, even if it is for localhost.

SKIP: {
    skip "No usable SOCK_DGRAM for socketpair", 24 if ($^O =~ /^(MSWin32|os2)\z/);
    skip "alarm doesn't interrupt I/O on this Perl", 24 if "$]" < 5.008;
    local $TODO = "socketpair not supported on $^O" if $^O eq 'nto';

    ok (socketpair (LEFT, RIGHT, AF_UNIX, SOCK_DGRAM, PF_UNSPEC),
	"socketpair (LEFT, RIGHT, AF_UNIX, SOCK_DGRAM, PF_UNSPEC)")
	or print "# \$\! = $!\n";

    if ($has_perlio) {
	binmode(LEFT,  ":bytes");
	binmode(RIGHT, ":bytes");
    }

    foreach (@left) {
	# is (syswrite (LEFT, $_), length $_, "write " . _qq ($_) . " to left");
	is (syswrite (LEFT, $_), length $_, "syswrite to left");
    }
    foreach (@right) {
	# is (syswrite (RIGHT, $_), length $_, "write " . _qq ($_) . " to right");
	is (syswrite (RIGHT, $_), length $_, "syswrite to right");
    }

    # stream socket, so our writes will become joined:
    my ($total);
    $total = join '', @right;
    foreach $expect (@right) {
	undef $buffer;
	is (sysread (LEFT, $buffer, length $total), length $expect, "read on left");
	is ($buffer, $expect, "content what we expected?");
    }
    $total = join '', @left;
    foreach $expect (@left) {
	undef $buffer;
	is (sysread (RIGHT, $buffer, length $total), length $expect, "read on right");
	is ($buffer, $expect, "content what we expected?");
    }

    ok (shutdown(LEFT, 1), "shutdown left for writing");

    # eof uses buffering. eof is indicated by a sysread of zero.
    # but for a datagram socket there's no way it can know nothing will ever be
    # sent
    SKIP: {
	skip "$^O does length 0 udp reads", 2 if ($^O eq 'os390');

	my $alarmed = 0;
	local $SIG{ALRM} = sub { $alarmed = 1; };
	print "# Approximate forever as 3 seconds. Wait 'forever'...\n";
	alarm 3;
	undef $buffer;
	is (sysread (RIGHT, $buffer, 1), undef,
	    "read on right should be interrupted");
	is ($alarmed, 1, "alarm should have fired");
    }

    alarm 30;

    foreach (@gripping) {
	is (syswrite (RIGHT, $_), length $_, "syswrite to right");
    }

    $total = join '', @gripping;
    foreach $expect (@gripping) {
	undef $buffer;
	is (sysread (LEFT, $buffer, length $total), length $expect, "read on left");
	is ($buffer, $expect, "content what we expected?");
    }

    ok (close LEFT, "close left");
    ok (close RIGHT, "close right");

} # end of DGRAM SKIP

kill "INT", $child or warn "Failed to kill child process $child: $!";
exit 0;