/usr/share/perl5/Devel/GDB/LowLevel.pm is in libdevel-gdb-perl 2.02-2.
This file is owned by root:root, with mode 0o644.
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use 5.006;
use strict;
use warnings;
use FileHandle;
use IPC::Open2;
use POSIX;
use threads::shared;
=head1 NAME
Devel::GDB::LowLevel - Low-level interface for communicating with GDB
=head1 DESCRIPTION
This module is used internally by L<Devel::GDB>. It handles the low-level I/O
of communicating with the GDB process.
=cut
our $VERSION = '2.0';
our $DEBUG;
our %PARAMS;
=head1 CONSTRUCTOR
=over
=item new
Spawns a GDB process. Because this class only facilitates communication with
GDB (I<not> with the inferior process being debugged), you have to decide what
to do with the C<STDIN>, C<STDOUT>, and C<STDERR> of that process. There are a
few options available:
=over
=item *
If STDIN is a tty, we can have the inferior process communicate directly
with the controlling tty (emulating the default behavior of gdb):
$gdb = new Devel::GDB::LowLevel( '-execfile' => $path_to_gdb,
'-params' => $extra_gdb_params );
=item *
Or, we can create an C<Expect> object to communicate with the inferior process:
$gdb = new Devel::GDB::LowLevel( '-create-expect' => 1 );
$expect = $gdb->get_expect_obj();
=item *
Or, we can create our own tty and use that:
$gdb = new Devel::GDB::LowLevel( '-use-tty' => '/dev/pts/123' );
=back
=back
=cut
sub new
{
my $class = shift or die "Who am I? no class provided. please read the manual\n" ;
# Load parameters
my $self = bless
{ '-execfile' => 'gdb', # gdb executable
'-params' => '' , # additional parameters
@_ }, $class ;
# Complain about any invalid parameters
foreach (keys %$self)
{
die "$class: Invalid parameter $_"
unless /^-(execfile|params|use-tty|create-expect)$/;
}
die "Cannot use both -use-tty and -create-expect!"
if $self->{'-use-tty'} && $self->{'-create-expect'};
# Create the TX lock
$self->{LOCK_tx} = &share(\my $tmp);
# Create a tty if necessary
my $tty = $self->{'-use-tty'} ||
$self->{'-create-expect'} && $self->_new_expect() ||
ttyname(0)
or die "$class: STDIN must be a tty when neither -use-tty nor -create-expect are specified";
# Build the parameter list
my @params = (ref $self->{'-params'} eq 'ARRAY') ? @{$self->{'-params'}} : split(/\s+/, $self->{'-params'});
unshift @params, '--interpreter=mi';
unshift @params, "--tty=$tty";
# Open the GDB pipe (Note that open2 will die if the fork() fails, but if
# exec() fails, we'll just get a SIGPIPE later.)
@{$self}{qw/PID IN OUT/} = $self->_pipe_open( $self->{'-execfile'}, @params );
return $self;
}
=head1 METHODS
=over
=item send
Sends a raw line of text to GDB. This should not contain any newlines (they
will be stripped). This method only sends a request, and does not wait for a
response.
=cut
sub send
{
my $self = shift;
my ($line) = @_;
$line =~ s/[\r\n]//s;
{
local $\ = "\n";
lock $self->{LOCK_tx};
my $fh = $self->{OUT};
print $fh $line;
print STDERR ">>> $line"
if $DEBUG;
}
}
=item get_reader
Returns the file handle from which to read GDB responses.
=cut
sub get_reader
{
my $self = shift;
return $self->{IN};
}
=item get_expect_obj
Returns the C<Expect> object created in the constructor. Dies if
C<'-create-expect'> was not passed to C<new>.
=cut
sub get_expect_obj
{
my $self = shift;
$self->{expect_obj} or die;
}
=item interrupt
Send SIGINT to the GDB session, interrupting the inferior process
(if any).
=cut
sub interrupt
{
my $self = shift;
kill 2, $self->{PID};
}
sub _new_expect
{
require Expect;
my $self = shift;
$self->{expect_obj} = new Expect;
$self->{expect_obj}->log_stdout(0);
# Disable echo on the pty
my $fd = fileno($self->{expect_obj});
my $termios = new POSIX::Termios;
$termios->getattr($fd);
$termios->setlflag($termios->getlflag & ~&POSIX::ECHO);
$termios->setattr($fd);
return $self->{expect_obj}->slave->ttyname;
}
sub _pipe_open
{
my $self = shift;
my @cmd = @_;
$SIG{PIPE} = sub { $self->_pipe_sig(); };
my ($in, $out) = (new FileHandle, new FileHandle) ;
my $pid = open2($in, $out, @cmd) ;
($pid, $in, $out)
}
sub _pipe_sig
{
my $self = shift;
# Check if $self->{PID} is really dead?
die "SIGPIPE: GDB terminated unexpectedly?";
}
1;
__END__
=back
=head1 SEE ALSO
L<IPC::Open2>
=head1 AUTHORS
Antal Novak E<lt>afn@cpan.orgE<gt>, Josef Ezra E<lt>jezra@cpan.orgE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright (C) 2007 by Antal Novak & Josef Ezra
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.8 or,
at your option, any later version of Perl 5 you may have available.
=cut
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