Re: [xml] libxml-2.6.22 SEGV on Solaris

[Daniel Veillard <veillard redhat com>]

On Wed, Oct 26, 2005 at 03:28:32AM -0500, Albert Chin wrote:
> "testapi -q" is generating a SEGV on Solaris. 2.6.22 was built with
> the Sun C compiler (though I duplicated the SEGV with gcc-3.4.3). From
> the coredump:
> $ dbx .libs/testapi core
> program terminated by signal SEGV (no mapping at the fault address)
> 0xfecaea90: strlen+0x0050:      ld       [%o2], %o1
> Current function is __xmlRaiseError
>   497           XML_GET_VAR_STR(msg, str);
> (dbx) where                                                                  
>   [1] strlen(0x0, 0xfffffaf0, 0x0, 0xffbff858, 0x0, 0x2b), at 0xfecaea90 
>   [2] _ndoprnt(0xff337956, 0xffbffa00, 0xffbff199, 0x0, 0x0, 0x0), at 0xfed135e4 
>   [3] vsnprintf(0x1ebf28, 0x96, 0xff337934, 0xffbff9fc, 0x7ffffc00, 0xfed6c950), at 0xfed15c64 
[...]

  Solaris libc dies on *printf( "%s", NULL) ... classic portability bug

> So, when no == 7, filename = NULL. Should xmlNewInputFromFile() return
> NULL if its filename argument is NULL like it does if its ctx argument
> is NULL?

  It should return NULL from __xmlParserInputBufferCreateFilename()
but buf == NULL will be detected first and __xmlLoaderErr() will be called.
Calling the error handler because you tried to load a NULL filename is
sensible, that should not be changed. What should is that the error
message printing should not segfault which is the real error. Turning
around the real bug by not calling it is not the right way to handle
this. Instead of calling blindly 
  __xmlLoaderErr(ctxt, "failed to load external entity \"%s\"\n",
                       (const char *) filename);

filename == NULL must be tested first to make a separate __xmlLoaderErr 
call.

        if (filename == NULL)
            __xmlLoaderErr(ctxt,
                           "failed to load external entity: NULL filename \n",
                           NULL);
        else
            __xmlLoaderErr(ctxt, "failed to load external entity \"%s\"\n",
                           (const char *) filename);

I commited this in CVS, could you double check it fixes the problem and that
no other similar error shows up ?

  thanks !

Daniel

-- 
Daniel Veillard      | Red Hat http://redhat.com/
veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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