Re: Re: call_init in libc6 2.3.6.ds1-11

On 2/17/07, John David Anglin <[email protected]> wrote:
> > /* The test for "addr & 2" below is to accomodate old binaries which
> >    violated the ELF ABI by pointing DT_INIT and DT_FINI at a function
> >    descriptor.  */
> > #define DL_DT_INIT_ADDRESS(map, addr) \
> >   ((Elf32_Addr)(addr) & 2 ? (addr) : DL_AUTO_FUNCTION_ADDRESS (map, addr))
>
> This is the ia64 define:
>
> #define DL_DT_INIT_ADDRESS(map, addr) DL_AUTO_FUNCTION_ADDRESS (map, addr)
>
> Calls to init on ia64 always use a function descriptor.
>
> While it's possible that DT_INIT and DT_FINI shouldn't point at function
> descriptors, the above hack can't be right since DL_DT_INIT_ADDRESS is used
> for calling init() from dl-init.c:
>
>       init_t init = (init_t) DL_DT_INIT_ADDRESS
>         (l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr);
>
>       /* Call the function.  */
>       init (argc, argv, env);

We might have been lucky in that init () called another function which
setup r19 for us before we accessed data. I agree completely that r19
should be set to the r19 of the module before calling init(), even if
it *is* or *isn't* a function descriptor.

I wrote dl-lookupcfg.h, and the code you see there is legacy. I
carried it forward without understanding what it meant.

c.