/* signal.c: a Hugh-approved signal handler. */#include <signal.h>#include <setjmp.h>#include "rc.h"#include "sigmsgs.h"#include "jbwrap.h"Jbwrap slowbuf;volatile SIG_ATOMIC_T slow, interrupt_happened;void (*sighandlers[NUMOFSIGNALS])(int);static volatile SIG_ATOMIC_T sigcount, caught[NUMOFSIGNALS];extern void catcher(int s) {	if (forked)		exit(1); /* exit unconditionally on a signal in a child process */	if (caught[s] == 0) {		sigcount++;		caught[s] = 1;	}	signal(s, catcher);	interrupt_happened = TRUE;	if (slow)		longjmp(slowbuf.j, 1);}extern void sigchk() {	void (*h)(int);	int s, i;	if (sigcount == 0)		return; /* ho hum; life as usual */	if (forked)		exit(1); /* exit unconditionally on a signal in a child process */	for (i = 0, s = -1; i < NUMOFSIGNALS; i++)		if (caught[i] != 0) {			s = i;			--sigcount;			caught[s] = 0;			break;		}	if (s == -1)		panic("all-zero sig vector with nonzero sigcount");	if ((h = sighandlers[s]) == SIG_DFL)		panic("caught signal set to SIG_DFL");	if (h == SIG_IGN)		panic("caught signal set to SIG_IGN");	(*h)(s);}extern void (*rc_signal(int s, void (*h)(int)))(int) {	void (*old)(int);	SIGCHK;	old = sighandlers[s];	if (h == SIG_DFL || h == SIG_IGN) {		signal(s, h);		sighandlers[s] = h;	} else {		sighandlers[s] = h;		signal(s, catcher);	}	return old;}extern void initsignal() {	void (*h)(int);	int i;	for (i = 1; i < NUMOFSIGNALS; i++) {		if ((h = signal(i, SIG_DFL)) != SIG_DFL)			signal(i, h);		sighandlers[i] = h;	}}