/*
 * Copyright (c) 1992, 1993, 1996
 *	Berkeley Software Design, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Berkeley Software
 *	Design, Inc.
 *
 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	BSDI signal.c,v 2.2 1996/04/08 19:33:06 bostic Exp
 */

#include "doscmd.h"

static void (*handler[NSIG])(struct sigframe *);
static char signal_stack[16 * 1024];

#define PSS(w) { char s; printf(w " @ %08x\n", (signal_stack + sizeof signal_stack) - &s); }

struct sigframe *saved_sigframe;
int saved_valid = 0; 

void
sanity_check(struct sigframe *sf)
{
#if 0
	static sigset_t oset;
	int i;

	for (i = 1; i < 32; ++i) {
		if (sigismember(&sf->sf_sc.sc_mask, i) != sigismember(&oset, i))
			fprintf(debugf, "Signal %s %s being blocked\n",
			    sys_signame[i],
			    sigismember(&sf->sf_sc.sc_mask, i) ? "now" : "no longer");
	}
	oset = sf->sf_sc.sc_mask;
#endif

	if (dead)
		fatal("attempting to return to vm86 while dead");
}

void
generichandler(struct sigframe sf)
{
#define	sc	(&sf.sf_sc)
	if (sc->sc_eflags & PSL_VM) {
		saved_sigframe = &sf;
		saved_valid = 1;
		if (handler[sf.sf_signum])
			(*handler[sf.sf_signum])(&sf);
		saved_valid = 0;
		sanity_check(&sf);
	} else {
		if (handler[sf.sf_signum])
			(*handler[sf.sf_signum])(&sf);
	}
#undef	sc
}

void
setsignal(int s, void (*h)(struct sigframe *))
{
	static int first = 1;
	struct sigaction sa;
	sigset_t set;

	if (first) {
		struct sigaltstack sstack;

		sstack.ss_sp = signal_stack;
		sstack.ss_size = sizeof signal_stack;
		sstack.ss_flags = 0;
		sigaltstack (&sstack, NULL);
		first = 0;
	}

	if (s >= 0 && s < NSIG) {
		handler[s] = h;

		sa.sa_handler = generichandler;
		sa.sa_mask = sigmask(SIGIO) | sigmask(SIGALRM);
		sa.sa_flags = SA_ONSTACK;
		sigaction(s, &sa, NULL);

		sigaddset(&set, s);
		sigprocmask(SIG_UNBLOCK, &set, 0);
	}
}