Re: CVS commit: src/lib/libpthread

["Valeriy E. Ushakov" <uwe%ptc.spbu.ru@localhost>]

On Thu, Nov 20, 2003 at 15:46:42 +0000, YAMAMOTO Takashi wrote:

> Module Name:  src
> Committed By: yamt
> Date:         Thu Nov 20 15:46:42 UTC 2003
> 
> Modified Files:
>       src/lib/libpthread: pthread_sig.c
> 
> Log Message:
> pthread__deliver_signal: swap oldmask and siginfo so that signal
> handler's stack doesn't stomp siginfo.
> this also fixes !__HAVE_SIGINFO, in that case
> pthread__signal_tramp assumes uc->uc_stack.ss_sp points the old
> signal mask.
> 
> pointed by uwe@.

Uh... I probably don't understand this code fully, but consider that
the uc is on the stack right above (lower addresses) the sigset_t
pointed to by maskp.  So if you set ss_sp in the uc to maskp and if
the platform passes arguments via stack, makecontext will write them
at the end of uc (above ss_sp = maskp).  We probably get away with
this because of the PAD in the ucontext.

SY, Uwe
-- 
uwe%ptc.spbu.ru@localhost                         |       Zu Grunde kommen
http://www.ptc.spbu.ru/~uwe/            |       Ist zu Grunde gehen