unhappy signals

unhappy signals

[Clint Adams]

% TRAPEXIT() { print boom }
% exit
boom
zsh: 8101 segmentation fault (core dumped)  zsh -f


Reversing the removehashnode hunk in 7349 fixes this,
but of course the TRAPQUIT example now segfaults.

What to do?

Re: unhappy signals

[Sven Wischnowsky]

Clint Adams wrote:

> % TRAPEXIT() { print boom }
> % exit
> boom
> zsh: 8101 segmentation fault (core dumped)  zsh -f
> 
> 
> Reversing the removehashnode hunk in 7349 fixes this,
> but of course the TRAPQUIT example now segfaults.
> 
> What to do?

The problem occurred as soon as a functions was called...

The problem was that `dosavetrap()' when called from `starttrapscope()' 
removed the definition for `TRAPEXIT()' but didn't reset the entry for 
it in `sigtrapped[]'. In `endtrapscope()' we tested `sigtrapped[SIGEXIT]' 
which was still `!= 0' even though we had removed the handler function. 
Then we tried to get the function definition, got a NULL pointer and
later tried to execute that. Bang.


This patch resets the `sigtrapped[]' entry in `dosavetrap()'. I'm not
sure if this is enough, maybe we have to execute some code from
`unsettrap()' there, too. So I think the final solution has to wait
until Peter reappears.

Bye
 Sven

diff -u oldsrc/signals.c Src/signals.c
--- oldsrc/signals.c	Thu Oct 28 10:12:49 1999
+++ Src/signals.c	Thu Oct 28 10:52:57 1999
@@ -668,6 +668,7 @@
 	st->list = sigfuncs[sig];
 	unsettrap(sig);
     }
+    sigtrapped[sig] = 0;
     notrapfree--;
     PERMALLOC {
 	if (!savetraps)
@@ -829,6 +830,7 @@
 
 	    if (sigtrapped[sig])
 		unsettrap(sig);
+	    sigtrapped[sig] = st->flags;
 	    if (st->flags) {
 		List list = (st->flags & ZSIG_FUNC) ?
 		    ((Shfunc) st->list)->funcdef : (List) st->list;

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de