Re: [PATCH 2/3] bpf_encoder: Translate SHN_XINDEX in symbol's st_shndx values

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sat, Jan 23, 2021 at 09:08:15PM +0100, Mark Wielaard wrote:
> Hi Jiri,
> 
> On Sat, 2021-01-23 at 19:51 +0100, Jiri Olsa wrote:
> > On Fri, Jan 22, 2021 at 02:55:51PM -0800, Andrii Nakryiko wrote:
> > > 
> > > > I don't understand this..  gelf_getsymshndx will return both
> > > > symbol and proper index, no? also sym_sec_idx is already
> > > > assigned from previou call
> > > 
> > > Reading (some) implementation of gelf_getsymshndx() that I found
> > > online, it won't set sym_sec_idx, if the symbol *doesn't* use
> > > extended
> > > numbering. But it will still return symbol data. So to return the
> > 
> > the latest upstream code seems to set it always,
> > but I agree we should be careful
> > 
> > Mark, any insight in here? thanks
> 
> GElf_Sym *
> gelf_getsymshndx (Elf_Data *symdata, Elf_Data *shndxdata, int ndx,
>                   GElf_Sym *dst, Elf32_Word *dstshndx)
> 
> Will always set *dst, but only set *dstshndx if both it and shndxdata
> are not NULL and no error occurred (the function returns NULL and set
> libelf_error in case of error).
> 
> So as long as shndxdata != NULL you can rely on *dstshndx being set.
> Otherwise you get the section index from dst->st_shndx.

ok, so it's as Andrii said, I'll make the extra check then

thanks,
jirka




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux