Re: [Bug-wget] wget 1.17 segfaults under openSUSE 13.1 (x86_64; glibc 2.18)

[Darshit Shah]

Another thing that I just remembered, this issue seems to pop up when the file 
being downloaded already exists on disk. Maybe, that is why you're seeing the 
different behaviour? 

Try downloading the file when it already exists and see if the problem can be 
reproduced on the newer system.

On 11/20, Darshit Shah wrote:
> This looks similar to another segfault I've seen. I'm not sure since 
> when it exists in the code, but I did come across one recently. That 
> case was caused when --trust-server-names -N and --content-disposition 
> were all provided to Wget. A wrong logic condition causes Wget to work 
> on output_filename = NULL which eventually resents in a segfault.
>
> I'm assuming the case you've provided is very similar to what I've 
> seen. I was using Clang when I saw this issue. Unfortunately, I'm 
> currently swamped with other work and am unable to look more deeply 
> into this.
>
> The stack trace provided does match my explanation above, so we should 
> be able to track it down and fix it. Some interplay of multiple 
> options is causing this bug, though I can't explain why it works with 
> one GCC version and not with another. The way I see it, it was a logic 
> bug in the code.
>
> Unfortunately, On 11/20, Schleusener, Jens wrote:
> > Hi,
> >
> > under some conditions I get with a self-compiled wget 1.17 binary on 
> > a 64-bit openSUSE 13.1 Linux system a segmentation fault (but the 
> > self-compiled wget 1.16.3 works correctly).
> >
> > I could reduce the problem to this usage case:
> >
> > wget -N --content-disposition http://ftp.gnu.org/gnu/wget/
> >
> > while the usage of only "-N" or "--content-disposition" let wget work.
> >
> > Sorry, I am not a C expert but nevertheless I tried to use gdb on 
> > the resulting core dump as best I could with the following result:
> >
> > Program terminated with signal SIGSEGV, Segmentation fault.
> > #0  0x00007f5b0899d42a in strlen () from /lib64/libc.so.6
> > (gdb) bt
> > #0  0x00007f5b0899d42a in strlen () from /lib64/libc.so.6
> > #1  0x0000000000420cdf in set_file_timestamp ()
> > #2  0x00000000004241e0 in http_loop ()
> > #3  0x0000000000433619 in retrieve_url ()
> > #4  0x000000000042c64b in main ()
> >
> > The used gcc version is
> > 4.8.1
> > and a "rpm -qf /lib64/libc.so.6" issues
> > glibc-2.18-4.38.1.x86_64
> >
> > On a newer openSUSE Leap 42.1 Linux system the "identically" 
> > compiled wget doesn't segfault and works ok. On that system the gcc 
> > version is
> > 4.8.5
> > and a "rpm -qf /lib64/libc.so.6" issues
> > glibc-2.19-17.4.x86_64
> >
> > Regards
> >
> > Jens
>
> --
> Thanking You,
> Darshit Shah



--
Thanking You,
Darshit Shah

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