updated 'ctimed'

[Steven M. Schultz]

	Enclosed is an updated version of the 'ctimed' process originally
	posted November 24th.  This version detects when it has been
	orphaned and exits, saving the resources that would otherwise
	remain allocated.  No more 'ctimed' left stranded by 'sendmail'
	when it starts up as a daemon.

#include	<signal.h>
#include	<stdio.h>
#include	<setjmp.h>
#include	<sys/ioctl.h>
#include	<sys/types.h>
#include	<sys/time.h>

#define	CTIME	1
#define	ASCTIME	2
#define	TZSET	3
#define	LOCALTIME 4
#define	GMTIME	5
#define	OFFTIME	6

extern	struct	tm	*offtime();

	jmp_buf	env;
	char	*cp, junk[52];
	long	l, off;
	int	timeout(), checkppid();
	struct	tm	tmtmp, *tp;

main()
	{
	register int i;
	struct	itimerval it;
	u_char	c;

	signal(SIGPIPE, SIG_DFL);
	for	(i = getdtablesize(); i > 2; i--)
		close(i);
/*
 * Need a timer running while we disassociate from the control terminal
 * in case of a modem line which has lost carrier.
*/
	timerclear(&it.it_interval);
	it.it_value.tv_sec = 5;
	it.it_value.tv_usec = 0;
	signal(SIGALRM, timeout);
	setitimer(ITIMER_REAL, &it, (struct itimerval *) NULL);
	if	(setjmp(env) == 0)
		{
		i = open("/dev/tty", 0);
		if	(i >= 0)
			{
			ioctl(i, TIOCNOTTY, NULL);
			close(i);
			}
		}
/*
 * Now start a timer with one minute refresh.  In the signal service
 * routine, check the parent process id to see if this process has
 * been orphaned and if so exit.  This is primarily aimed at removing
 * the 'ctimed' process left behind by 'sendmail's multi-fork startup
 * but may prove useful in preventing accumulation of 'ctimed' processes
 * in other circumstances as well.  Normally this process is short
 * lived.
*/
	it.it_interval.tv_sec = 60;
	it.it_interval.tv_usec = 0;
	it.it_value.tv_sec = 60;
	it.it_value.tv_usec = 0;
	signal(SIGALRM, checkppid);
	setitimer(ITIMER_REAL, &it, (struct itimerval *) NULL);

	while	(read(fileno(stdin), &c, 1) == 1)
		{
		switch	(c)
			{
			case	CTIME:
				l = 0L;
				getb(fileno(stdin), &l, sizeof l);
				cp = ctime(&l);
				write(fileno(stdout), cp, 26);
				break;
			case	ASCTIME:
				getb(fileno(stdin), &tmtmp, sizeof tmtmp);
				cp = asctime(&tmtmp);
				write(fileno(stdout), cp, 26);
				break;
			case	TZSET:
				(void) tzset();
				break;
			case	LOCALTIME:
				l = 0L;
				getb(fileno(stdin), &l, sizeof l);
				tp = localtime(&l);
				write(fileno(stdout), tp, sizeof (*tp));
				strcpy(junk, tp->tm_zone);
				junk[24] = '\0';
				write(fileno(stdout), junk, 24);
				break;
			case	GMTIME:
				l = 0L;
				getb(fileno(stdin), &l, sizeof l);
				tp = gmtime(&l);
				write(fileno(stdout), tp, sizeof (*tp));
				strcpy(junk, tp->tm_zone);
				junk[24] = '\0';
				write(fileno(stdout), junk, 24);
				break;
			case	OFFTIME:
				getb(fileno(stdin), &l, sizeof l);
				getb(fileno(stdin), &off, sizeof off);
				tp = offtime(&l, off);
				write(fileno(stdout), tp, sizeof (*tp));
				break;
			default:
				abort("switch");
			}
		}
	}

getb(f, p, n)
	int	f;
	register char	*p;
	register int	n;
	{
	register int	i;

	while	(n)
		{
		i = read(f, p, n);
		if	(i <= 0)
			return;
		p += i;
		n -= i;
		}
	}

timeout()
	{

	longjmp(env, 1);
	}

checkppid()
	{

	if	(getppid() == 1)
		exit(0);
	}