Asp Forum - Tidy segfault on Linux

Lee Fyock

12/5/2007 7:58:00 PM

Hi--

I'm using the Ruby tidy gem to clean some user-input HTML. It works
splendidly on my Mac development machine, but seg faults on a CentOS
linux box.

I've tracked through the code, and the crash occurs in Tidybuf.rb's
to_s function. The "struct.bp" method returns a non-nil value (that
indicates a zero size), but the struct.size is some huge number which
varies run-to-run.

I've googled a ton, and there are a lot of people who have hit
segfaults using Ruby and tidy. Some of the issue seem to have been a
namespace conflict between Graphics/ImageMagick and Tidy, but we've
fixed that (by renaming tidy's GetToken function and recompiling), and
are still hitting a seg fault.

More detail:

Using a fresh Rails 1.2.5 app, I've stepped in console thru the parts
of Tidyobj.rb's clean method, like so:

require 'tidy'
tidy = Tidyobj.new
@doc = Tidylib.create
@outbuf = Tidybuf.new
str = 'hi there!'
rc = -1
rc = Tidylib.parse_string(@doc, str)
rc = Tidylib.clean_and_repair(@doc) if rc >= 0
rc = (Tidylib.opt_parse_value(@doc, :force_output, true) == 1 ? rc :
-1) if rc > 1
rc = Tidylib.save_buffer(@doc, @outbuf.struct) if rc >= 0

At this point:
>> @outbuf.struct.size
=> 154846656
>> @outbuf.struct.bp
=> #<DL::PtrData:0x0x949aa38 ptr=0x0x29c4d0 size=0 free=0x(nil)>

Then:
>> @outbuf.to_s
/usr/lib/ruby/site_ruby/1.8/tidy/tidybuf.rb:39: [BUG] Segmentation
fault
ruby 1.8.4 (2005-12-24) [i386-linux]
Aborted (core dumped)

The shorter way to reproduce this is:
>> tidy=Tidyobj.new
>> tidy.clean 'hi'
/usr/lib/ruby/site_ruby/1.8/tidy/tidybuf.rb:39: [BUG] Segmentation
fault
ruby 1.8.4 (2005-12-24) [i386-linux]
Aborted (core dumped)

If anyone has a clue, please help!

Thanks,
Lee

5 Answers

scott@ideum.com

12/7/2007 12:39:00 AM

Lee,

Check out this URL for a patch:

http://rubyforge.org/tracker/index.php?func=detail&aid=10007&group_id=435&...

It seems to have fixed the problem for me.

Good luck,

Scott

Lee Fyock

12/14/2007 7:06:00 PM

Excellent, thanks, I'll try it out.

Lee

On Dec 6, 7:39 pm, "sc...@ideum.com" <csl3...@gmail.com> wrote:
> Lee,
>
> Check out this URL for a patch:
>
> http://rubyforge.org/tracker/index.php?func=detail&aid=10007&am......
>
> It seems to have fixed the problem for me.
>
> Good luck,
>
> Scott

Bob Foxworthington

7/14/2008 11:32:00 AM

Hi Lee & Scott,

we ran into the excat same issue Lee described in
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-t...

We tried the patch as suggested by Scott in
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-t...

Unfortunately, no luck... we still segfault.

Just wondering if you were able to solve it... and if so, how?

We have Ruby 1.8.5, Tidy Gem 1.1.2, libtidy 0.99 on CentOS 5.2 (x86_64).

One thing we found is that Tidy seems to only segfault if one feeds it
*valid* HTML. If one feeds it bad HTML, it doesn't crash (see example
below).

Thanks!

Bob

---8<-------------------------------------------------------------------------

require "rubygems"
require "tidy"

Tidy.path = "/usr/lib64/libtidy.so"

Tidy.open do |t|
puts "*** BAD SAMPLE"
t.clean "<html>I am bad HTML!</html>"
puts t.errors
puts t.diagnostics
end

Tidy.open do |t|
puts "*** GOOD SAMPLE"
t.clean '<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">' +
'<html><head><title>foo</title></head><body><p>bar</p></body></html>'
puts t.errors
puts t.diagnostics
end

---8<-------------------------------------------------------------------------

Outputs the following:

*** BAD SAMPLE
line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 1 column 7 - Warning: plain text isn't allowed in <head> elements
line 1 column 7 - Info: <head> previously mentioned
line 1 column 7 - Warning: inserting implicit <body>
line 1 column 7 - Warning: inserting missing 'title' element
Info: Document content looks like HTML 3.2
4 warnings, 0 errors were found!

*** GOOD SAMPLE
(eval):5: [BUG] Segmentation fault
ruby 1.8.5 (2006-08-25) [x86_64-linux]

Aborted

erilar

11/6/2013 6:37:00 PM

In article <MPG.2ce477bd95d0b486989899@news.eternal-september.org>,
David Barnett <dbar3518@bigpond.net.au> wrote:

> In article <alpine.LNX.2.02.1311041729340.28461
> @darkstar.example.org>, et472@ncf.ca says...
> >
> > On Mon, 4 Nov 2013, erilar wrote:
> >
> > > In article <alpine.LNX.2.02.1311031542481.26090@darkstar.example.org>,
> > > Michael Black <et472@ncf.ca> wrote:
> > >
> > >> On Sun, 3 Nov 2013, Ubiquitous wrote:
> > >>
> > >>> drache@chibardun.net.invalid wrote:
> > >>>> Ubiquitous <weberm@polaris.net> wrote:
> > >>>
> > >>>>> What did you watch?
> > >>>>
> > >>>> Dr Who on PBS; there was an episode I hadn't seen, and next week they
> > >>>> start the next season, which I believe is the last with Matt Smith.
> > >>>
> > >>> PBS? I did not know they aired Doctor Who.
> > >>>
> > >> I wondered too. The Vermont PBS station used to air Doctor Who, but that
> > >> was decades back, the Doctor with the curly hair. But that was a long
> > >> time ago. It seems like Doctor Who has gone mainstream in more recent
> > >> times, and has appeared on more commercial channels.
> > >
> > > I first watched it when Tom Baker(curly hair, long scarf) was the
> > > Doctor, then later earlier and later incarnations, always on Minnesota
> > > PBS back then. I've been dependent on PBS for BBC series for years.
> > >
> > It was Tom Baker I was thinking of, he's the only Doctor Who that comes to
> > mind. I was going to say "and a scarf" but I wsan't sure if that was
> > specific to his Doctor Who or if they all had scarves.
> >
> > Michael
>
> My late wife knitted me Dr Who scarves, which were a
> comfort in a cold London.

My daughter knitted herself one when she was in college 8-)

--
Erilar, biblioholic medievalist

David Barnett

11/6/2013 10:49:00 PM

In article <l5cmnd$kic$1@news.albasani.net>,
ahk@chinet.com says...
>
> David Barnett <dbar3518@bigpond.net.au> wrote:
> >In article <alpine.LNX.2.02.1311041729340.28461
> >@darkstar.example.org>, et472@ncf.ca says...
> >>
> >> On Mon, 4 Nov 2013, erilar wrote:
> >>
> >> > In article <alpine.LNX.2.02.1311031542481.26090@darkstar.example.org>,
> >> > Michael Black <et472@ncf.ca> wrote:
> >> >
> >> >> On Sun, 3 Nov 2013, Ubiquitous wrote:
> >> >>
> >> >>> drache@chibardun.net.invalid wrote:
> >> >>>> Ubiquitous <weberm@polaris.net> wrote:
> >> >>>
> >> >>>>> What did you watch?
> >> >>>>
> >> >>>> Dr Who on PBS; there was an episode I hadn't seen, and next week they
> >> >>>> start the next season, which I believe is the last with Matt Smith.
> >> >>>
> >> >>> PBS? I did not know they aired Doctor Who.
> >> >>>
> >> >> I wondered too. The Vermont PBS station used to air Doctor Who, but that
> >> >> was decades back, the Doctor with the curly hair. But that was a long
> >> >> time ago. It seems like Doctor Who has gone mainstream in more recent
> >> >> times, and has appeared on more commercial channels.
> >> >
> >> > I first watched it when Tom Baker(curly hair, long scarf) was the
> >> > Doctor, then later earlier and later incarnations, always on Minnesota
> >> > PBS back then. I've been dependent on PBS for BBC series for years.
> >> >
> >> It was Tom Baker I was thinking of, he's the only Doctor Who that comes to
> >> mind. I was going to say "and a scarf" but I wsan't sure if that was
> >> specific to his Doctor Who or if they all had scarves.
> >>
> >> Michael
> >
> >My late wife knitted me Dr Who scarves, which were a
> >comfort in a cold London.
>
> Were you able to lassoo objects out of the sky?

LOL

--
David Barnett

comp.lang.ruby

Tidy segfault on Linux

Lee Fyock

scott@ideum.com

Lee Fyock

Bob Foxworthington

erilar

David Barnett

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