dosig.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

static char sccsid[] = "@(#)dosig.c	4.2  83/07/31";

/*
 * Handle signal trapping from version 6 or
 * version 7 compatability mode programs.
 *	Art Wetzel	November 1979
 */

#ifdef TRACE
#include <stdio.h>
#endif
#include <signal.h>
#include "defs.h"

unsigned int  sigvals[NSIG+1];

/* actual catch point for all signals */
sigcatch(signum, faultcode, scp)
	int signum, faultcode;
	struct sigcontext *scp;
{
	unsigned short *pcptr;
	extern getregs();
	if(incompat) {
		/* hurry up and get the registers before they are destroyed */
		getregs();
	} else {
		/* we were in native mode simulating a sys call */
		/* set it up with the old values */
		dosig(signum, pc);
		/* go back where we were doing the sys call */
		return(0);
	}
	/* figure out the pc */
	pcptr = (unsigned short *) &scp->sc_pc;
	pc = (unsigned short *) *pcptr;
	/* get the psl with condition codes */
	psl = 0x83c00000 | (scp->sc_ps & 017);
	/* actually do the thing */
	if (sigvals[signum] != (unsigned int)SIG_DFL &&
	    (sigvals[signum] & (unsigned int)SIG_IGN) == 0)
		dosig(signum, pc);
	/* go back to compatability mode and the signal routine there */
	sigsetmask(scp->sc_mask);
	incompat++;
	compat();
}

/* routine to set up pdp11 space for return from a signal */
dosig(signum, from)
	int signum, from;
{
	unsigned short *sp;

#ifdef TRACE
	fprintf(stderr,"Caught sig %d from 0%o -> 0%o\n",signum,(pc-1),*(pc-1));
#endif
	/* where is the stack */
	sp = (unsigned short *)regs[6];
	/* stack up psw condition codes so rti works */
	*(--sp) = psl & 017;
	/* stack pc */
	*(--sp) = (unsigned short)(int)pc;
	/* reset stack pointer */
	regs[6] = (unsigned short)(int)sp;
	/* reset pc to signal catching routine */
	pc = (unsigned short *)sigvals[signum];
	signal(signum, SIG_DFL);
}