Re: [PATCH] gdb: care for dynamic objfiles in build_id_bfd_get ()

["Jan Vraný" <Jan.Vrany@labware.com>]

On Tue, 2023-01-10 at 07:14 -0700, Tom Tromey wrote:
> > > > > > "Jan" == Jan Vrany via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
> Jan> Accessing gdb.Objfile.build_id caused GDB to crash when objfile is
> Jan> dynamic, that is created by JIT reader API. Similarly, invoking
> Jan> gdb.Symtab.fullname() caused a crash. Possibly there are other paths
> Jan> that may trigger the crash.
> 
> Is there a patch already for the fullname bug?

Hmm, it's been a while I wrote that patch (when working on Python
alternative to JIT-reader API) and I believe I encountered a case
case where fullname() crashed since it (indirectly) called 
build_id_bfd_get(). 

I tried to reproduce it now and could not, perhaps I can be reproduced
once other patches are in. 

I'll remove that sentence from commit message to avoid confusion:


    gdb: care for dynamic objfiles in build_id_bfd_get ()
    
    Accessing gdb.Objfile.build_id caused GDB to crash when objfile is
    dynamic, that is created by JIT reader API.
    
    The issue was NULL-pointer dereferencing in build_id_bfd_get () because
    dynamic objfiles have no underlaying BFD structure. This commit fixes

Jan

> 
> Jan> +  /* Dynamic objfiles such as ones created by JIT reader API
> Jan> +     have no underlaying bfd structure (that is, objfile->obfd
> Jan> +     is NULL).  */
> Jan> +  if (abfd == nullptr)
> Jan> +    return NULL;
> 
> Use 'nullptr' in new code.  This is ok with this change.
> 
> thank you,
> Tom
>