port-macppc/43619: SA_RESETHAND is broken

[jmmv%netbsd.org@localhost]

>Number:         43619
>Category:       port-macppc
>Synopsis:       SA_RESETHAND is broken
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-macppc-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jul 14 21:25:00 +0000 2010
>Originator:     Julio Merino
>Release:        NetBSD 5.1_RC3
>Organization:
Julio Merino
>Environment:
System: NetBSD mini.julipedia.org 5.1_RC3 NetBSD 5.1_RC3 (MINI) #17: Sat Jul 10 
16:01:11 IST 2010  
jmmv%mini.julipedia.org@localhost:/home/jmmv/os/netbsd/obj.macppc/usr/src/sys/arch/macppc/compile/MINI
 macppc
Architecture: powerpc
Machine: macppc
>Description:
        Signals programmed with the SA_RESETHAND flag set cause the program     
        to either crash or get stuck in an infinite loop when the signal is
        received.

        This problem causes some programs to misbehave, which is pretty
        annoying in a server setting.  For example, the monotone server gets
        stuck when started from rc.d as part of the system boot process (I
        suspect because it receives some signal).

        Haven't been able to confirm if this happens in current yet.
>How-To-Repeat:
        Run this program and see it crash in macppc (but work fine on
        amd64).  Replace SA_RESETHAND with 0 and see it work:

#include <signal.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>

static bool handler_called = false;

static void
handler(int signo)
{
    handler_called = true;
}

int
main(void)
{
    struct sigaction sa;

    sa.sa_flags = SA_RESETHAND;
    sa.sa_handler = &handler;
    sigemptyset(&sa.sa_mask);

    sigaction(SIGUSR1, &sa, NULL);
    kill(0, SIGUSR1);
    return handler_called ? EXIT_SUCCESS : EXIT_FAILURE;
}

        The backtrace of the crashed program does not shed much light:

(gdb) bt
#0  0xefeedf24 in kill () from /usr/lib/libc.so.12
#1  0x018008a4 in main () at crash.c:24
(gdb)
>Fix:
        

>Unformatted: