/* $NetBSD: ac.c,v 1.27 2022/05/24 06:28:02 andvar Exp $ */

/*-
 * Copyright (c) 1994 Christopher G. Demetriou
 * Copyright (c) 1994 Simon J. Gerraty
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR OR CONTRIBUTORS 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.
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: ac.c,v 1.27 2022/05/24 06:28:02 andvar Exp $");
#endif

#include <sys/types.h>

#include <err.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <utmp.h>
#include <ttyent.h>

/*
 * this is for our list of currently logged in sessions
 */
struct utmp_list {
	struct utmp_list *next;
	struct utmp usr;
};

/*
 * this is for our list of users that are accumulating time.
 */
struct user_list {
	struct user_list *next;
	char	name[UT_NAMESIZE+1];
	time_t	secs;
};

/*
 * this is for choosing whether to ignore a login
 */
struct tty_list {
	struct tty_list *next;
	char	name[UT_LINESIZE+3];
	int	len;
	int	ret;
};

/*
 * globals - yes yuk
 */
static time_t	Total = 0;
static time_t	FirstTime = 0;
static int	Flags = 0;
static struct user_list *Users = NULL;
static struct tty_list *Ttys = NULL;
static int Maxcon = 0, Ncon = 0;
static char (*Con)[UT_LINESIZE] = NULL;

#define NEW(type) (type *)malloc(sizeof (type))

#define is_login_tty(line) \
	(bsearch(line, Con, Ncon, sizeof(Con[0]), compare) != NULL)

#define	AC_W	1				/* not _PATH_WTMP */
#define	AC_D	2				/* daily totals (ignore -p) */
#define	AC_P	4				/* per-user totals */
#define	AC_U	8				/* specified users only */
#define	AC_T	16				/* specified ttys only */

#ifdef DEBUG
static int Debug = 0;
#endif

static int		ac(FILE *);
static struct tty_list	*add_tty(char *);
static int		do_tty(char *);
static FILE		*file(const char *);
static struct utmp_list	*log_in(struct utmp_list *, struct utmp *);
static struct utmp_list	*log_out(struct utmp_list *, struct utmp *);
#ifdef notdef
static int		on_console(struct utmp_list *);
#endif
static void		find_login_ttys(void);
static void		show(const char *, time_t);
static void		show_today(struct user_list *, struct utmp_list *,
    time_t);
static void		show_users(struct user_list *);
static struct user_list	*update_user(struct user_list *, char *, time_t);
static int		compare(const void *, const void *);
__dead static void	usage(void);

/*
 * open wtmp or die
 */
static FILE *
file(const char *name)
{
	FILE *fp;

	if (strcmp(name, "-") == 0)
		fp = stdin;
	else if ((fp = fopen(name, "r")) == NULL)
		err(1, "%s", name);
	/* in case we want to discriminate */
	if (strcmp(_PATH_WTMP, name))
		Flags |= AC_W;
	return fp;
}

static struct tty_list *
add_tty(char *name)
{
	struct tty_list *tp;
	char *rcp;

	Flags |= AC_T;
	
	if ((tp = NEW(struct tty_list)) == NULL)
		err(1, "malloc");
	tp->len = 0;				/* full match */
	tp->ret = 1;				/* do if match */
	if (*name == '!') {			/* don't do if match */
		tp->ret = 0;
		name++;
	}
	(void)strlcpy(tp->name, name, sizeof (tp->name));
	if ((rcp = strchr(tp->name, '*')) != NULL) {	/* wild card */
		*rcp = '\0';
		tp->len = strlen(tp->name);	/* match len bytes only */
	}
	tp->next = Ttys;
	Ttys = tp;
	return Ttys;
}

/*
 * should we process the named tty?
 */
static int
do_tty(char *name)
{
	struct tty_list *tp;
	int def_ret = 0;
	
	for (tp = Ttys; tp != NULL; tp = tp->next) {
		if (tp->ret == 0)		/* specific don't */
			def_ret = 1;		/* default do */
		if (tp->len != 0) {
			if (strncmp(name, tp->name, tp->len) == 0)
				return tp->ret;
		} else {
			if (strncmp(name, tp->name, sizeof (tp->name)) == 0)
				return tp->ret;
		}
	}
	return def_ret;
}

static int
compare(const void *a, const void *b)
{
	return strncmp(a, b, UT_LINESIZE);
}

/*
 * Deal correctly with multiple virtual consoles/login ttys. 
 * We read the ttyent's from /etc/ttys and classify as login
 * ttys ones that are running getty and they are turned on.
 */
static void
find_login_ttys(void)
{
	struct ttyent *tty;
	char (*nCon)[UT_LINESIZE];

	if ((Con = malloc((Maxcon = 10) * sizeof(Con[0]))) == NULL)
		err(1, "malloc");

	setttyent();
	while ((tty = getttyent()) != NULL)
		if ((tty->ty_status & TTY_ON) != 0 &&
		    strstr(tty->ty_getty, "getty") != NULL) {
			if (Ncon == Maxcon) {
				if ((nCon = realloc(Con, (Maxcon + 10) *
				    sizeof(Con[0]))) == NULL)
					err(1, "malloc");
				Con = nCon;
				Maxcon += 10;
			}
			strlcpy(Con[Ncon++], tty->ty_name, UT_LINESIZE);
		}
	endttyent();
	qsort(Con, Ncon, sizeof(Con[0]), compare);
}

#ifdef notdef
/*
 * is someone logged in on Console/login tty?
 */
static int
on_console(struct utmp_list *head)
{
	struct utmp_list *up;

	for (up = head; up; up = up->next)
		if (is_login_tty(up->usr.ut_line))
			return 1;

	return 0;
}
#endif

/*
 * update user's login time
 */
static struct user_list *
update_user(struct user_list *head, char *name, time_t secs)
{
	struct user_list *up;

	for (up = head; up != NULL; up = up->next) {
		if (strncmp(up->name, name, sizeof (up->name) - 1) == 0) {
			up->secs += secs;
			Total += secs;
			return head;
		}
	}
	/*
	 * not found so add new user unless specified users only
	 */
	if (Flags & AC_U)
		return head;
	
	if ((up = NEW(struct user_list)) == NULL)
		err(1, "malloc");
	up->next = head;
	(void)strlcpy(up->name, name, sizeof (up->name));
	up->secs = secs;
	Total += secs;
	return up;
}

int
main(int argc, char **argv)
{
	FILE *fp;
	int c;

	fp = NULL;
	while ((c = getopt(argc, argv, "Ddpt:w:")) != -1) {
		switch (c) {
#ifdef DEBUG
		case 'D':
			Debug++;
			break;
#endif
		case 'd':
			Flags |= AC_D;
			break;
		case 'p':
			Flags |= AC_P;
			break;
		case 't':			/* only do specified ttys */
			add_tty(optarg);
			break;
		case 'w':
			fp = file(optarg);
			break;
		case '?':
		default:
			usage();
		}
	}

	find_login_ttys();

	if (optind < argc) {
		/*
		 * initialize user list
		 */
		for (; optind < argc; optind++) {
			Users = update_user(Users, argv[optind], 0L);
		}
		Flags |= AC_U;			/* freeze user list */
	}
	if (Flags & AC_D)
		Flags &= ~AC_P;
	if (fp == NULL) {
		/*
		 * if _PATH_WTMP does not exist, exit quietly
		 */
		if (access(_PATH_WTMP, 0) != 0 && errno == ENOENT)
			return 0;
		
		fp = file(_PATH_WTMP);
	}
	ac(fp);
	
	return 0;
}

/*
 * print login time in decimal hours
 */
static void
show(const char *name, time_t secs)
{
	(void)printf("\t%-*s %8.2f\n", UT_NAMESIZE, name,
	    ((double)secs / 3600));
}

static void
show_users(struct user_list *list)
{
	struct user_list *lp;

	for (lp = list; lp; lp = lp->next)
		show(lp->name, lp->secs);
}

/*
 * print total login time for 24hr period in decimal hours
 */
static void
show_today(struct user_list *users, struct utmp_list *logins, time_t secs)
{
	struct user_list *up;
	struct utmp_list *lp;
	char date[64];
	time_t yesterday = secs - 1;

	(void)strftime(date, sizeof (date), "%b %e  total",
	    localtime(&yesterday));

	/* restore the missing second */
	yesterday++;
	
	for (lp = logins; lp != NULL; lp = lp->next) {
		secs = yesterday - lp->usr.ut_time;
		Users = update_user(Users, lp->usr.ut_name, secs);
		lp->usr.ut_time = yesterday;	/* as if they just logged in */
	}
	secs = 0;
	for (up = users; up != NULL; up = up->next) {
		secs += up->secs;
		up->secs = 0;			/* for next day */
	}
 	if (secs)
		(void)printf("%s %11.2f\n", date, ((double)secs / 3600));
}

/*
 * log a user out and update their times.
 * if ut_line is "~", we log all users out as the system has
 * been shut down.
 */
static struct utmp_list *
log_out(struct utmp_list *head, struct utmp *up)
{
	struct utmp_list *lp, *lp2, *tlp;
	time_t secs;
	
	for (lp = head, lp2 = NULL; lp != NULL; )
		if (*up->ut_line == '~' || strncmp(lp->usr.ut_line, up->ut_line,
		    sizeof (up->ut_line)) == 0) {
			secs = up->ut_time - lp->usr.ut_time;
			Users = update_user(Users, lp->usr.ut_name, secs);
#ifdef DEBUG
			if (Debug)
				printf("%-.*s %-.*s: %-.*s logged out (%2d:%02d:%02d)\n",
				    19, ctime(&up->ut_time),
				    sizeof (lp->usr.ut_line), lp->usr.ut_line,
				    sizeof (lp->usr.ut_name), lp->usr.ut_name,
				    secs / 3600, (secs % 3600) / 60, secs % 60);
#endif
			/*
			 * now lose it
			 */
			tlp = lp;
			lp = lp->next;
			if (tlp == head) {
				head = lp;
			} else if (lp2 != NULL)
				lp2->next = lp;
			free(tlp);
		} else {
			lp2 = lp;
			lp = lp->next;
		}
	return head;
}


/*
 * if do_tty says ok, login a user
 */
struct utmp_list *
log_in(struct utmp_list *head, struct utmp *up)
{
	struct utmp_list *lp;

	/*
	 * If we are doing specified ttys only, we ignore
	 * anything else.
	 */
	if (Flags & AC_T)
		if (!do_tty(up->ut_line))
			return head;

	/*
	 * go ahead and log them in
	 */
	if ((lp = NEW(struct utmp_list)) == NULL)
		err(1, "malloc");
	lp->next = head;
	head = lp;
	memmove((char *)&lp->usr, (char *)up, sizeof (struct utmp));
#ifdef DEBUG
	if (Debug) {
		printf("%-.*s %-.*s: %-.*s logged in", 19,
		    ctime(&lp->usr.ut_time), sizeof (up->ut_line),
		       up->ut_line, sizeof (up->ut_name), up->ut_name);
		if (*up->ut_host)
			printf(" (%-.*s)", sizeof (up->ut_host), up->ut_host);
		putchar('\n');
	}
#endif
	return head;
}

static int
ac(FILE *fp)
{
	struct utmp_list *lp, *head = NULL;
	struct utmp usr;
	struct tm *ltm;
	time_t secs = 0;
	int day = -1;
	
	while (fread((char *)&usr, sizeof(usr), 1, fp) == 1) {
		if (!FirstTime)
			FirstTime = usr.ut_time;
		if (Flags & AC_D) {
			ltm = localtime(&usr.ut_time);
			if (day >= 0 && day != ltm->tm_yday) {
				day = ltm->tm_yday;
				/*
				 * print yesterday's total
				 */
				secs = usr.ut_time;
				secs -= ltm->tm_sec;
				secs -= 60 * ltm->tm_min;
				secs -= 3600 * ltm->tm_hour;
				show_today(Users, head, secs);
			} else
				day = ltm->tm_yday;
		}
		switch(*usr.ut_line) {
		case '|':
			secs = usr.ut_time;
			break;
		case '{':
			secs -= usr.ut_time;
			/*
			 * adjust time for those logged in
			 */
			for (lp = head; lp != NULL; lp = lp->next)
				lp->usr.ut_time -= secs;
			break;
		case '~':			/* reboot or shutdown */
			head = log_out(head, &usr);
			FirstTime = usr.ut_time; /* shouldn't be needed */
			break;
		default:
			/*
			 * if they came in on tty[p-y]*, then it is only
			 * a login session if the ut_host field is non-empty,
			 * or this tty is a login tty [eg. a console]
			 */
			if (*usr.ut_name) {
				if ((strncmp(usr.ut_line, "tty", 3) != 0 &&
				    strncmp(usr.ut_line, "dty", 3) != 0) ||
				    strchr("pqrstuvwxyzPQRST", usr.ut_line[3]) == 0 ||
				    *usr.ut_host != '\0' ||
				    is_login_tty(usr.ut_line))
					head = log_in(head, &usr);
#ifdef DEBUG
				else if (Debug)
					printf("%-.*s %-.*s: %-.*s ignored\n",
					    19, ctime(&usr.ut_time),
					    sizeof (usr.ut_line), usr.ut_line,
					    sizeof (usr.ut_name), usr.ut_name);
#endif
			} else
				head = log_out(head, &usr);
			break;
		}
	}
	(void)fclose(fp);
	usr.ut_time = time((time_t *)0);
	(void)strcpy(usr.ut_line, "~");
	
	if (Flags & AC_D) {
		ltm = localtime(&usr.ut_time);
		if (day >= 0 && day != ltm->tm_yday) {
			/*
			 * print yesterday's total
			 */
			secs = usr.ut_time;
			secs -= ltm->tm_sec;
			secs -= 60 * ltm->tm_min;
			secs -= 3600 * ltm->tm_hour;
			show_today(Users, head, secs);
		}
	}
	/*
	 * anyone still logged in gets time up to now
	 */
	head = log_out(head, &usr);

	if (Flags & AC_D)
		show_today(Users, head, time((time_t *)0));
	else {
		if (Flags & AC_P)
			show_users(Users);
		show("total", Total);
	}
	return 0;
}

static void
usage(void)
{

	(void)fprintf(stderr,
	    "usage: %s [-d | -p] [-t tty] [-w wtmp] [users ...]\n",
	    getprogname());
	exit(1);
}
