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This queue is for tickets about the Nmap-Scanner CPAN distribution.

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The Basics
Id: 83910
Status: new
Priority: 0/
Queue: Nmap-Scanner

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Owner: Nobody in particular
Requestors: kgc [...] corp.sonic.net
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Subject: Bug handling large outputs from nmap
Date: Tue, 12 Mar 2013 15:08:27 -0700
To: bug-Nmap-Scanner [...] rt.cpan.org
From: Kelsey Cummings <kgc [...] corp.sonic.net>
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Since the module as written blocks on reading stderr from namp, namp's stdout output buffer can fill and block causing things to hang. Included patch updates the code to use select loop on the output to prevent this from happening and to allow reading of large amounts of data from nmap. diff -ru scan_rpc-0.005-BACKUP/lib/Nmap/Scanner/Backend/XML.pm scan_rpc-0.005/lib/Nmap/Scanner/Backend/XML.pm --- scan_rpc-0.005-BACKUP/lib/Nmap/Scanner/Backend/XML.pm 2013-03-12 13:49:02.100461965 -0700 +++ scan_rpc-0.005/lib/Nmap/Scanner/Backend/XML.pm 2013-03-12 14:41:51.155406282 -0700 @@ -30,11 +30,39 @@ my $cmdline = shift; my $error = shift; + my $readbuf = ""; + my $errorbuf = ""; + # Suppress warnings about reading unopened handle $^W = 0; - my $err = join('', (<$error>)); + + my $fd_set = new IO::Select(); + $fd_set->add($read); + $fd_set->add($error); + + while (1) { + my ($rh_set) = IO::Select->select($fd_set, undef, undef, 10); + + for my $fd (@$rh_set) { + my $tbuf = ""; + if ($fd == $read) { + my $retval = sysread($read, $tbuf, 1024); + $readbuf .= $tbuf; + goto DONE if (!defined($retval) || $retval == 0); + } + if ($fd == $error) { + my $retval = sysread($error, $tbuf, 1024); + $errorbuf .= $tbuf; + goto DONE if (!defined($retval) || $retval == 0); + } + } + } + DONE: + $^W = 1; + my $err = $errorbuf; + if ($err ne '') { close($read); @@ -53,15 +81,12 @@ my $handler = NmapHandler->new($self); my $parser = XML::SAX::ParserFactory->parser(Handler => $handler); - eval { $parser->parse_file($read) }; + eval { $parser->parse_string($readbuf) }; if (defined($@) && ($@ ne '')) { - my $msg = join('', <$read>); - - Nmap::Scanner::debug("bytes in input stream: " . tell($read)); - Nmap::Scanner::debug("bytes in error stream: " . tell($error)); + my $msg = $readbuf; warn <<EOF; <nmap-error> -- Kelsey Cummings - kgc@corp.sonic.net sonic.net, inc. System Architect 2260 Apollo Way 707.522.1000 Santa Rosa, CA 95407


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