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git/t/test-terminal.perl
Paul Tan 18d8c26930 test_terminal: redirect child process' stdin to a pty
When resuming, git-am detects if we are trying to feed it patches or not
by checking if stdin is a TTY.

However, the test library redirects stdin to /dev/null. This makes it
difficult, for instance, to test the behavior of "git am -3" when
resuming, as git-am will think we are trying to feed it patches and
error out.

Support this use case by extending test-terminal.perl to create a
pseudo-tty for the child process' standard input as well.

Note that due to the way the code is structured, the child's stdin
pseudo-tty will be closed when we finish reading from our stdin. This
means that in the common case, where our stdin is attached to /dev/null,
the child's stdin pseudo-tty will be closed immediately. Some operations
like isatty(), which git-am uses, require the file descriptor to be
open, and hence if the success of the command depends on such functions,
test_terminal's stdin should be redirected to a source with large amount
of data to ensure that the child's stdin is not closed, e.g.

	test_terminal git am --3way </dev/zero

Cc: Jonathan Nieder <jrnieder@gmail.com>
Cc: Jeff King <peff@peff.net>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-12 10:33:46 -07:00

104 lines
2.3 KiB
Perl
Executable file

#!/usr/bin/perl
use 5.008;
use strict;
use warnings;
use IO::Pty;
use File::Copy;
# Run @$argv in the background with stdio redirected to $in, $out and $err.
sub start_child {
my ($argv, $in, $out, $err) = @_;
my $pid = fork;
if (not defined $pid) {
die "fork failed: $!"
} elsif ($pid == 0) {
open STDIN, "<&", $in;
open STDOUT, ">&", $out;
open STDERR, ">&", $err;
close $in;
close $out;
exec(@$argv) or die "cannot exec '$argv->[0]': $!"
}
return $pid;
}
# Wait for $pid to finish.
sub finish_child {
# Simplified from wait_or_whine() in run-command.c.
my ($pid) = @_;
my $waiting = waitpid($pid, 0);
if ($waiting < 0) {
die "waitpid failed: $!";
} elsif ($? & 127) {
my $code = $? & 127;
warn "died of signal $code";
return $code + 128;
} else {
return $? >> 8;
}
}
sub xsendfile {
my ($out, $in) = @_;
# Note: the real sendfile() cannot read from a terminal.
# It is unspecified by POSIX whether reads
# from a disconnected terminal will return
# EIO (as in AIX 4.x, IRIX, and Linux) or
# end-of-file. Either is fine.
copy($in, $out, 4096) or $!{EIO} or die "cannot copy from child: $!";
}
sub copy_stdin {
my ($in) = @_;
my $pid = fork;
if (!$pid) {
xsendfile($in, \*STDIN);
exit 0;
}
close($in);
return $pid;
}
sub copy_stdio {
my ($out, $err) = @_;
my $pid = fork;
defined $pid or die "fork failed: $!";
if (!$pid) {
close($out);
xsendfile(\*STDERR, $err);
exit 0;
}
close($err);
xsendfile(\*STDOUT, $out);
finish_child($pid) == 0
or exit 1;
}
if ($#ARGV < 1) {
die "usage: test-terminal program args";
}
my $master_in = new IO::Pty;
my $master_out = new IO::Pty;
my $master_err = new IO::Pty;
$master_in->set_raw();
$master_out->set_raw();
$master_err->set_raw();
$master_in->slave->set_raw();
$master_out->slave->set_raw();
$master_err->slave->set_raw();
my $pid = start_child(\@ARGV, $master_in->slave, $master_out->slave, $master_err->slave);
close $master_in->slave;
close $master_out->slave;
close $master_err->slave;
my $in_pid = copy_stdin($master_in);
copy_stdio($master_out, $master_err);
my $ret = finish_child($pid);
# If the child process terminates before our copy_stdin() process is able to
# write all of its data to $master_in, the copy_stdin() process could stall.
# Send SIGTERM to it to ensure it terminates.
kill 'TERM', $in_pid;
finish_child($in_pid);
exit($ret);