#ifndef	lint
static	char *sccsid = "@(#)last.c	4.3 (Berkeley) 2/28/81";
#endif
/*
 * last
 */
#include <sys/types.h>
#include <stdio.h>
#include <signal.h>
#include <stat.h>
#include <utmp.h>

#define NMAX	sizeof(buf[0].ut_name)
#define LMAX	sizeof(buf[0].ut_line)
#define	SECDAY	(24*60*60)

#define	lineq(a,b)	(!strncmp(a,b,LMAX))
#define	nameq(a,b)	(!strncmp(a,b,NMAX))

#define MAXTTYS 256

char	**argv;
int	argc;

struct	utmp buf[128];
char	ttnames[MAXTTYS][LMAX+1];
long	logouts[MAXTTYS];

char	*ctime(), *strspl();
int	onintr();

main(ac, av)
	char **av;
{
	register int i;
	long bl;
	int wtmp;
	char *ct;
	register struct utmp *bp;
	long otime;
	struct stat stb;
	int print;
	char * crmsg = (char *)0;
 
	time(&buf[0].ut_time);
	ac--, av++;
	argc = ac;
	argv = av;
	for (i = 0; i < argc; i++) {
		if (strlen(argv[i])>2)
			continue;
		if (!strcmp(argv[i], "~"))
			continue;
		if (getpwnam(argv[i]))
			continue;
		argv[i] = strspl("tty", argv[i]);
	}
	wtmp = open("/usr/adm/wtmp", 0);
	if (wtmp < 0) {
		perror("/usr/adm/wtmp");
		exit(1);
	}
	fstat(wtmp, &stb);
	bl = (stb.st_size + sizeof (buf)-1) / sizeof (buf);
	if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
		signal(SIGINT, onintr);
		signal(SIGQUIT, onintr);
	}
	for (bl--; bl >= 0; bl--) {
		lseek(wtmp, (off_t)bl * sizeof (buf), 0);
		bp = &buf[read(wtmp, (char *) buf, sizeof (buf)) / sizeof(buf[0]) - 1];
		for ( ; bp >= buf; bp--) {
			print = want(bp);
			if (print) {
				ct = ctime(&bp->ut_time);
				printf("%-*.*s  %-*.*s  %10.10s %5.5s ",
				    NMAX, NMAX, bp->ut_name,
				    LMAX, LMAX, bp->ut_line, ct, 11+ct);
			}
			for (i = 0; i < MAXTTYS; i++) {
				if (ttnames[i][0] == 0) {
					strncpy(ttnames[i], bp->ut_line,
					    sizeof(bp->ut_line));
					otime = logouts[i];
					logouts[i] = bp->ut_time;
					break;
				}
				if (lineq(ttnames[i], bp->ut_line)) {
					otime = logouts[i];
					logouts[i] = bp->ut_time;
					break;
				}
			}
			if (print) {
				if (lineq(bp->ut_line, "~"))
					printf("\n");
				else if (otime == 0)
					printf("  still logged in\n");
				else {
					long delta;
					if (otime < 0) {
						otime = -otime;
						printf("- %s", crmsg);
					} else
						printf("- %5.5s",
						    ctime(&otime)+11);
					delta = otime - bp->ut_time;
					if (delta < SECDAY)
					    printf("  (%5.5s)\n",
						asctime(gmtime(&delta))+11);
					else
					    printf(" (%ld+%5.5s)\n",
						delta / SECDAY,
						asctime(gmtime(&delta))+11);
				}
				fflush(stdout);
			}
			if (lineq(bp->ut_line, "~")) {
				for (i = 0; i < MAXTTYS; i++)
					logouts[i] = -bp->ut_time;
				if (nameq(bp->ut_name, "shutdown"))
					crmsg = "down ";
				else
					crmsg = "crash";
			}
		}
	}
	ct = ctime(&buf[0].ut_time);
	printf("\nwtmp begins %10.10s %5.5s \n", ct, ct + 11);
	exit(0);
}

onintr(signo)
	int signo;
{
	char *ct;

	if (signo == SIGQUIT)
		signal(SIGQUIT, onintr);
	ct = ctime(&buf[0].ut_time);
	printf("\ninterrupted %10.10s %5.5s \n", ct, ct + 11);
	if (signo == SIGINT)
		exit(1);
}

want(bp)
	struct utmp *bp;
{
	register char **av;
	register int ac;

	if (bp->ut_line[0] == '~' && bp->ut_name[0] == '\0')
		strcpy(bp->ut_name, "reboot");		/* bandaid */
	if (bp->ut_name[0] == 0)
		return (0);
	if (argc == 0)
		return (1);
	av = argv;
	for (ac = 0; ac < argc; ac++) {
		if (nameq(*av, bp->ut_name) || lineq(*av, bp->ut_line))
			return (1);
		av++;
	}
	return (0);
}

char *
strspl(left, right)
	char *left, *right;
{
	char *res = (char *)malloc(strlen(left)+strlen(right)+1);

	strcpy(res, left);
	strcat(res, right);
	return (res);
}