Bug #58911 for Net-SSH2: can't write to remote files lines longer than 32748 chars

Mon Jun 28 16:14:25 2010 salvatore.bonaccorso [...] gmail.com - Ticket created

CC:	560867-submitter [...] bugs.debian.org, 560867 [...] bugs.debian.org
Subject:	can't write to remote files lines longer than 32748 chars
Date:	Mon, 28 Jun 2010 22:14:14 +0200
To:	bug-Net-SSH2 [...] rt.cpan.org
From:	Salvatore Bonaccorso <salvatore.bonaccorso [...] gmail.com>

Hi Running the following small script hangs, when sending 32748 chars, if one CTRL-C's the files get written anyway. Sending only 32747 chars works on the other hand side well. ---(example)------------------------------------------------------------ #!/usr/bin/perl -W use strict; use Fcntl; use warnings FATAL => qw (all); use Net::SSH2; my $ssh2 = Net::SSH2->new(); $ssh2->debug(1); $ssh2->connect('hostname') or die $!; $ssh2->auth_password('username','password'); my $sftp = $ssh2->sftp(); my $remote = $sftp->open("/home/username/foo.txt", O_WRONLY | O_CREAT | O_TRUNC); print $remote 'A' x 32748; ------------------------------------------------------------------------ This was orginally in Debian a bugreport with 27442 chars, but I was not able to reproduce. I'm now with 32748. See for details [1]. [1] http://bugs.debian.org/560867 Any ideas about that? Bests Salvatore

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Mon Jun 28 16:35:40 2010 rkitover [...] cpan.org - Correspondence added

Subject:	Re: [rt.cpan.org #58911] can't write to remote files lines longer than 32748 chars
Date:	Mon, 28 Jun 2010 16:35:08 -0400
To:	bug-Net-SSH2 [...] rt.cpan.org
From:	Rafael Kitover <rkitover [...] io.com>

I'll take a look, what happens if you split the string in half and write twice? "Salvatore Bonaccorso via RT" <bug-Net-SSH2@rt.cpan.org> wrote: Show quoted text

>Mon Jun 28 16:14:25 2010: Request 58911 was acted upon. >Transaction: Ticket created by salvatore.bonaccorso@gmail.com > Queue: Net-SSH2 > Subject: can't write to remote files lines longer than 32748 chars > Broken in: (no value) > Severity: (no value) > Owner: Nobody > Requestors: salvatore.bonaccorso@gmail.com > Status: new > Ticket <URL: https://rt.cpan.org/Ticket/Display.html?id=58911 > > > >Hi > >Running the following small script hangs, when sending 32748 chars, if >one CTRL-C's the files get written anyway. Sending only 32747 chars >works on the other hand side well. > >---(example)------------------------------------------------------------ >#!/usr/bin/perl -W > >use strict; >use Fcntl; >use warnings FATAL => qw (all); >use Net::SSH2; > >my $ssh2 = Net::SSH2->new(); >$ssh2->debug(1); >$ssh2->connect('hostname') or die $!; >$ssh2->auth_password('username','password'); >my $sftp = $ssh2->sftp(); >my $remote = $sftp->open("/home/username/foo.txt", O_WRONLY | O_CREAT | O_TRUNC); > >print $remote 'A' x 32748; >------------------------------------------------------------------------ > >This was orginally in Debian a bugreport with 27442 chars, but I was >not able to reproduce. I'm now with 32748. See for details [1]. > > [1] http://bugs.debian.org/560867 > >Any ideas about that? > >Bests >Salvatore >

-- Sent from my Android phone with K-9. Please excuse my brevity.

Mon Jun 28 16:35:42 2010 The RT System itself - Status changed from 'new' to 'open'

Tue Jun 29 09:38:37 2010 salvatore.bonaccorso [...] gmail.com - Correspondence added

CC:	560867-submitter [...] bugs.debian.org, 560867 [...] bugs.debian.org
Subject:	Re: [rt.cpan.org #58911] can't write to remote files lines longer than 32748 chars
Date:	Tue, 29 Jun 2010 15:38:26 +0200
To:	Rafael Kitover via RT <bug-Net-SSH2 [...] rt.cpan.org>
From:	Salvatore Bonaccorso <salvatore.bonaccorso [...] gmail.com>

Hi On Mon, Jun 28, 2010 at 04:35:41PM -0400, Rafael Kitover via RT wrote: Show quoted text

> <URL: https://rt.cpan.org/Ticket/Display.html?id=58911 > > > I'll take a look, what happens if you split the string in half and write twice?

Thanks. If I split the print up into two calls, each writing 16374 chars it doesn't hang. Please let me know if I can try to provide more informations. The version currently used is 0.30 (0.30-1 package in Debian). Bests and thanks Salvatore

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Wed Aug 26 08:37:11 2015 salva [...] cpan.org - Correspondence added

Fixed in the development version. Now write retries until all the data is written or some error happens.

Wed Aug 26 08:37:13 2015 salva [...] cpan.org - Status changed from 'open' to 'resolved'

Mon Sep 28 12:39:58 2015 CARNIL [...] cpan.org - Correspondence added

Hi, On Wed Aug 26 08:37:11 2015, SALVA wrote: Show quoted text

> Fixed in the development version. > > Now write retries until all the data is written or some error happens.

I unfortunately still can cause the behavior with the reproducer script with increased values (now). Regards, Salvatore

Mon Sep 28 17:10:27 2015 sfandino [...] yahoo.com - Correspondence added

Subject:	Re: [rt.cpan.org #58911] can't write to remote files lines longer than 32748 chars
Date:	Mon, 28 Sep 2015 21:10:09 +0000 (UTC)
To:	"bug-Net-SSH2 [...] rt.cpan.org" <bug-Net-SSH2 [...] rt.cpan.org>
From:	Salvador Fandino <sfandino [...] yahoo.com>

Show quoted text

----- Original Message -----

> From: Salvatore Bonaccorso via RT <bug-Net-SSH2@rt.cpan.org> > To: > Cc: > Sent: Monday, September 28, 2015 6:39 PM > Subject: [rt.cpan.org #58911] can't write to remote files lines longer than 32748 chars > > Queue: Net-SSH2 > Ticket <URL: https://rt.cpan.org/Ticket/Display.html?id=58911 > > > Hi, > > On Wed Aug 26 08:37:11 2015, SALVA wrote:

>> Fixed in the development version. >> >> Now write retries until all the data is written or some error happens.

> > I unfortunately still can cause the behavior with the reproducer script with > increased values (now).

Oh, sorry, I didn't noticed you were talking about SFTP as a similar problem was fixed for the regular channels. Anyway, SFTP support in libssh2 is way suboptimal and particularly the libssh2_sftp_write function (which Net::SFTP::File::write wraps) has an almost impossible to use API and that can not be fixed from the Perl side. That is what you are seeing. I have just documented that on the development version of the module. My advice would be to switch to Net::SFTP::Foreign which implements the SFTP protocol fully in Perl and can also run on top of Net::SSH2 via the Net::SFTP::Foreign::Backend::Net_SSH2 module (Net::SSH2 is used only as the SSH transport layer there, the SFTP part is untouched).