path: root/usr.bin/rusers/rusers.c

/*	$OpenBSD: rusers.c,v 1.29 2007/09/02 15:19:34 deraadt Exp $	*/

/*
 * Copyright (c) 2001, 2003 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */
/*-
 *  Copyright (c) 1993 John Brezak
 *  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.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `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 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.
 */

#ifndef lint
static const char rcsid[] = "$OpenBSD: rusers.c,v 1.29 2007/09/02 15:19:34 deraadt Exp $";
#endif /* not lint */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <rpc/rpc.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_rmt.h>
#include <rpcsvc/rusers.h>
#include <rpcsvc/rnusers.h>	/* Old protocol version */
#include <arpa/inet.h>
#include <net/if.h>
#include <err.h>
#include <errno.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

/* Preferred formatting */
#define HOST_WIDTH 17
#define LINE_WIDTH 8
#define NAME_WIDTH 8

#define MAX_BROADCAST_SIZE 1400

struct host_info {
	u_int count;
	u_int idle;
	char *host;
	rusers_utmp *users;
} *hostinfo;

void print_entry(struct host_info *, int);
void fmt_idle(int, char *, size_t);
void onehost(char *);
void allhosts(void);
void sorthosts(void);
void expandhosts(void);
void alarmclock(int);
char *estrndup(const char *, size_t);
struct host_info *add_host(char *);
int hcompare(const void *, const void *);
int icompare(const void *, const void *);
int ucompare(const void *, const void *);
bool_t rusers_reply(char *, struct sockaddr_in *);
bool_t rusers_reply_3(char *, struct sockaddr_in *);
enum clnt_stat get_reply(int, in_port_t, u_long, struct rpc_msg *,
    struct rmtcallres *, bool_t (*)(char *, struct sockaddr_in *));
enum clnt_stat rpc_setup(int *, XDR *, struct rpc_msg *,
    struct rmtcallargs *, AUTH *, char *);
__dead void usage(void);

int aflag, hflag, iflag, lflag, uflag;
u_int nentries, maxentries;
long termwidth;
extern char *__progname;

int
main(int argc, char **argv)
{
	struct winsize win;
	char *cp, *ep;
	int ch;
	
	while ((ch = getopt(argc, argv, "ahilu")) != -1)
		switch (ch) {
		case 'a':
			aflag = 1;
			break;
		case 'h':
			hflag = 1;
			break;
		case 'i':
			iflag = 1;
			break;
		case 'l':
			lflag = 1;
			break;
		case 'u':
			uflag = 1;
			break;
		default:
			usage();
			/*NOTREACHED*/
		}

	if (hflag + iflag + uflag > 1)
		usage();

	if (isatty(STDOUT_FILENO)) {
		if ((cp = getenv("COLUMNS")) != NULL && *cp != '\0') {
			termwidth = strtol(cp, &ep, 10);
			if (*ep != '\0' || termwidth >= INT_MAX ||
			    termwidth < 0)
				termwidth = 0;
		}
		if (termwidth == 0 &&
		    ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
		    win.ws_col > 0)
			termwidth = win.ws_col;
		else
			termwidth = 80;
	} else
		termwidth = 80;
	setlinebuf(stdout);

	if (argc == optind) {
		if (hflag || iflag || uflag) {
			puts("Collecting responses...");
			allhosts();
			sorthosts();
		} else
			allhosts();
	} else {
		aflag = 1;
		for (; optind < argc; optind++)
			(void) onehost(argv[optind]);
		if (hflag || iflag || uflag)
			sorthosts();
	}

	exit(0);
}

struct host_info *
add_host(char *host)
{
	int i;

	for (i = 0; i < nentries; i++) {
		/* Existing entry. */
		if (strcmp(host, hostinfo[i].host) == 0)
			return(NULL);
	}

	/* New entry, allocate space if needed and store. */
	if (nentries == maxentries) {
		maxentries += 128;
		hostinfo = realloc(hostinfo,
		    sizeof(*hostinfo) * maxentries);
		if (hostinfo == NULL)
			err(1, NULL);
	}
	if ((hostinfo[nentries].host = strdup(host)) == NULL)
		err(1, NULL);
	return(&hostinfo[nentries++]);
}

void
fmt_idle(int idle, char *idle_time, size_t idle_time_len)
{
	int days, hours, minutes, seconds;

	switch (idle) {
	case 0:
		*idle_time = '\0';
		break;
	case INT_MAX:
		strlcpy(idle_time, "??", idle_time_len);
		break;
	default:
		seconds = idle;
		days = seconds / (60*60*24);
		seconds %= (60*60*24);
		hours = seconds / (60*60);
		seconds %= (60*60);
		minutes = seconds / 60;
		seconds %= 60;
		if (idle >= (24*60*60))
			snprintf(idle_time, idle_time_len,
			    "%d day%s, %d:%02d:%02d", days,
			    days > 1 ? "s" : "", hours, minutes, seconds);
		else if (idle >= (60*60))
			snprintf(idle_time, idle_time_len, "%2d:%02d:%02d",
			    hours, minutes, seconds);
		else if (idle > 60)
			snprintf(idle_time, idle_time_len, "%2d:%02d",
			    minutes, seconds);
		else
			snprintf(idle_time, idle_time_len, "   :%02d", idle);
		break;
	}
}

bool_t
rusers_reply(char *replyp, struct sockaddr_in *raddrp)
{
	utmpidlearr *up = (utmpidlearr *)replyp;
	struct host_info *entry;
	struct hostent *hp;
	rusers_utmp *ut;
	char *host;
	int i;
	
	if (!aflag && up->uia_cnt == 0)
		return(0);

	hp = gethostbyaddr((char *)&raddrp->sin_addr,
	    sizeof(struct in_addr), AF_INET);
	if (hp)
		host = hp->h_name;
	else
		host = inet_ntoa(raddrp->sin_addr);
	if ((entry = add_host(host)) == NULL)
		return(0);

	if (up->uia_cnt == 0)
		ut = NULL;
	else if ((ut = calloc(up->uia_cnt, sizeof(*ut))) == NULL)
		err(1, NULL);
	entry->users = ut;
	entry->count = up->uia_cnt;
	entry->idle = UINT_MAX;
	for (i = 0; i < up->uia_cnt; i++, ut++) {
		ut->ut_user = estrndup(up->uia_arr[i]->ui_utmp.ut_name,
		    RNUSERS_MAXUSERLEN);
		ut->ut_line = estrndup(up->uia_arr[i]->ui_utmp.ut_line,
		    RNUSERS_MAXLINELEN);
		ut->ut_host = estrndup(up->uia_arr[i]->ui_utmp.ut_host,
		    RNUSERS_MAXHOSTLEN);
		ut->ut_time = up->uia_arr[i]->ui_utmp.ut_time;
		ut->ut_idle = up->uia_arr[i]->ui_idle;
		if (ut->ut_idle < entry->idle)
			entry->idle = ut->ut_idle;
	}
	
	if (!hflag && !iflag && !uflag) {
		print_entry(entry, lflag && entry->count);
		for (i = 0, ut = entry->users; i < entry->count; i++, ut++) {
			free(ut->ut_user);
			free(ut->ut_line);
			free(ut->ut_host);
		}
		free(entry->users);
	}
	
	return(0);
}

bool_t
rusers_reply_3(char *replyp, struct sockaddr_in *raddrp)
{
	utmp_array *up3 = (utmp_array *)replyp;
	struct host_info *entry;
	struct hostent *hp;
	rusers_utmp *ut;
	char *host;
	int i;
	
	if (!aflag && up3->utmp_array_len == 0)
		return(0);

	hp = gethostbyaddr((char *)&raddrp->sin_addr,
	    sizeof(struct in_addr), AF_INET);
	if (hp)
		host = hp->h_name;
	else
		host = inet_ntoa(raddrp->sin_addr);
	if ((entry = add_host(host)) == NULL)
		return(0);

	if (up3->utmp_array_len == 0)
		ut = NULL;
	else if ((ut = calloc(up3->utmp_array_len, sizeof(*ut))) == NULL)
		err(1, NULL);
	entry->users = ut;
	entry->count = up3->utmp_array_len;
	entry->idle = UINT_MAX;
	for (i = 0; i < up3->utmp_array_len; i++, ut++) {
		ut->ut_user = estrndup(up3->utmp_array_val[i].ut_user,
		    RUSERS_MAXUSERLEN);
		ut->ut_line = estrndup(up3->utmp_array_val[i].ut_line,
		    RUSERS_MAXLINELEN);
		ut->ut_host = estrndup(up3->utmp_array_val[i].ut_host,
		    RUSERS_MAXHOSTLEN);
		ut->ut_time = up3->utmp_array_val[i].ut_time;
		ut->ut_idle = up3->utmp_array_val[i].ut_idle;
		if (ut->ut_idle < entry->idle)
			entry->idle = ut->ut_idle;
	}
	
	if (!hflag && !iflag && !uflag) {
		print_entry(entry, lflag && entry->count);
		for (i = 0, ut = entry->users; i < entry->count; i++, ut++) {
			free(ut->ut_user);
			free(ut->ut_line);
			free(ut->ut_host);
		}
		free(entry->users);
	}
	
	return(0);
}

void
onehost(char *host)
{
	utmpidlearr up;
	utmp_array up3;
	CLIENT *rusers_clnt;
	struct sockaddr_in sin;
	struct hostent *hp;
	struct timeval tv = { 25, 0 };
	int error;
	
	memset(&sin, 0, sizeof sin);

	hp = gethostbyname(host);
	if (hp == NULL)
		errx(1, "unknown host \"%s\"", host);

	/* Try version 3 first. */
	rusers_clnt = clnt_create(host, RUSERSPROG, RUSERSVERS_3, "udp");
	if (rusers_clnt == NULL) {
		clnt_pcreateerror(__progname);
		exit(1);
	}

	memset(&up3, 0, sizeof(up3));
	error = clnt_call(rusers_clnt, RUSERSPROC_NAMES, xdr_void, NULL,
	    xdr_utmp_array, &up3, tv);
	switch (error) {
	case RPC_SUCCESS:
		sin.sin_addr.s_addr = *(int *)hp->h_addr;
		rusers_reply_3((char *)&up3, &sin);
		clnt_destroy(rusers_clnt);
		return;
	case RPC_PROGVERSMISMATCH:
		clnt_destroy(rusers_clnt);
		break;
	default:
		clnt_perror(rusers_clnt, __progname);
		clnt_destroy(rusers_clnt);
		exit(1);
	}

	/* Fall back to version 2. */
	rusers_clnt = clnt_create(host, RUSERSPROG, RUSERSVERS_IDLE, "udp");
	if (rusers_clnt == NULL) {
		clnt_pcreateerror(__progname);
		exit(1);
	}

	memset(&up, 0, sizeof(up));
	error = clnt_call(rusers_clnt, RUSERSPROC_NAMES, xdr_void, NULL,
	    xdr_utmpidlearr, &up, tv);
	if (error != RPC_SUCCESS) {
		clnt_perror(rusers_clnt, __progname);
		clnt_destroy(rusers_clnt);
		exit(1);
	}
	sin.sin_addr.s_addr = *(int *)hp->h_addr;
	rusers_reply((char *)&up, &sin);
	clnt_destroy(rusers_clnt);
}

enum clnt_stat
get_reply(int sock, in_port_t port, u_long xid, struct rpc_msg *msgp,
    struct rmtcallres *resp, bool_t (*callback)(char *, struct sockaddr_in *))
{
	ssize_t inlen;
	socklen_t fromlen;
	struct sockaddr_in raddr;
	char inbuf[UDPMSGSIZE];
	XDR xdr;

retry:
	msgp->acpted_rply.ar_verf = _null_auth;
	msgp->acpted_rply.ar_results.where = (caddr_t)resp;
	msgp->acpted_rply.ar_results.proc = xdr_rmtcallres;

	fromlen = sizeof(struct sockaddr);
	inlen = recvfrom(sock, inbuf, sizeof(inbuf), 0,
	    (struct sockaddr *)&raddr, &fromlen);
	if (inlen < 0) {
		if (errno == EINTR)
			goto retry;
		return (RPC_CANTRECV);
	}
	if (inlen < sizeof(u_int32_t))
		goto retry;

	/*
	 * If the reply we got matches our request, decode the
	 * replay and pass it to the callback function.
	 */
	xdrmem_create(&xdr, inbuf, (u_int)inlen, XDR_DECODE);
	if (xdr_replymsg(&xdr, msgp)) {
		if ((msgp->rm_xid == xid) &&
		    (msgp->rm_reply.rp_stat == MSG_ACCEPTED) &&
		    (msgp->acpted_rply.ar_stat == SUCCESS)) {
			raddr.sin_port = htons(port);
			(void)(*callback)(resp->results_ptr, &raddr);
		}
	}
	xdr.x_op = XDR_FREE;
	msgp->acpted_rply.ar_results.proc = xdr_void;
	(void)xdr_replymsg(&xdr, msgp);
	(void)(*resp->xdr_results)(&xdr, resp->results_ptr);
	xdr_destroy(&xdr);

	return(RPC_SUCCESS);
}

enum clnt_stat
rpc_setup(int *fdp, XDR *xdr, struct rpc_msg *msg, struct rmtcallargs *args,
    AUTH *unix_auth, char *buf)
{
	int on = 1;

	if ((*fdp = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
		return(RPC_CANTSEND);

	if (setsockopt(*fdp, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0)
		return(RPC_CANTSEND);

	msg->rm_xid = arc4random();
	msg->rm_direction = CALL;
	msg->rm_call.cb_rpcvers = RPC_MSG_VERSION;
	msg->rm_call.cb_prog = PMAPPROG;
	msg->rm_call.cb_vers = PMAPVERS;
	msg->rm_call.cb_proc = PMAPPROC_CALLIT;
	msg->rm_call.cb_cred = unix_auth->ah_cred;
	msg->rm_call.cb_verf = unix_auth->ah_verf;

	xdrmem_create(xdr, buf, MAX_BROADCAST_SIZE, XDR_ENCODE);
	if (!xdr_callmsg(xdr, msg) || !xdr_rmtcall_args(xdr, args))
		return(RPC_CANTENCODEARGS);

	return(RPC_SUCCESS);
}

void
allhosts(void)
{
	enum clnt_stat stat;
	struct itimerval timeout;
	AUTH *unix_auth;
	size_t outlen[2];
	int sock[2] = { -1, -1 };
	int i, maxfd, rval;
	u_long xid[2], port[2];
	fd_set *fds = NULL;
	struct sockaddr_in *sin, baddr;
	struct rmtcallargs args;
	struct rmtcallres res[2];
	struct rpc_msg msg[2];
	struct ifaddrs *ifa, *ifap = NULL;
	char buf[2][MAX_BROADCAST_SIZE];
	utmpidlearr up;
	utmp_array up3;
	XDR xdr;

	if ((unix_auth = authunix_create_default()) == NULL)
		err(1, "can't create auth handle");

	if (getifaddrs(&ifap) != 0)
		err(1, "can't get list of interface addresses");

	memset(&up, 0, sizeof(up));
	memset(&up3, 0, sizeof(up3));
	memset(&baddr, 0, sizeof(baddr));
	memset(&res, 0, sizeof(res));
	memset(&msg, 0, sizeof(msg));
	memset(&timeout, 0, sizeof(timeout));

	args.prog = RUSERSPROG;
	args.vers = RUSERSVERS_IDLE;
	args.proc = RUSERSPROC_NAMES;
	args.xdr_args = xdr_void;
	args.args_ptr = NULL;

	stat = rpc_setup(&sock[0], &xdr, &msg[0], &args, unix_auth, buf[0]);
	if (stat != RPC_SUCCESS)
		goto cleanup;
	xid[0] = msg[0].rm_xid;
	outlen[0] = xdr_getpos(&xdr);
	xdr_destroy(&xdr);

	args.vers = RUSERSVERS_3;
	stat = rpc_setup(&sock[1], &xdr, &msg[1], &args, unix_auth, buf[1]);
	if (stat != RPC_SUCCESS)
		goto cleanup;
	xid[1] = msg[1].rm_xid;
	outlen[1] = xdr_getpos(&xdr);
	xdr_destroy(&xdr);

	maxfd = MAX(sock[0], sock[1]) + 1;
	fds = (fd_set *)calloc(howmany(maxfd, NFDBITS), sizeof(fd_mask));
	if (fds == NULL)
		err(1, NULL);

	baddr.sin_len = sizeof(struct sockaddr_in);
	baddr.sin_family = AF_INET;
	baddr.sin_port = htons(PMAPPORT);
	baddr.sin_addr.s_addr = htonl(INADDR_ANY);

	res[0].port_ptr = &port[0];
	res[0].xdr_results = xdr_utmpidlearr;
	res[0].results_ptr = (caddr_t)&up;

	res[1].port_ptr = &port[1];
	res[1].xdr_results = xdr_utmp_array;
	res[1].results_ptr = (caddr_t)&up3;

	(void)signal(SIGALRM, alarmclock);

	/*
	 * We do 6 runs through the loop.  On even runs we send
	 * a version 3 broadcast.  On odd ones we send a version 2
	 * broadcast.  This should give version 3 replies enough
	 * of an 'edge' over the old version 2 ones in most cases.
	 * We select() waiting for replies for 5 seconds in between
	 * each broadcast.
	 */
	for (i = 0; i < 6; i++) {
		for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
			if (ifa->ifa_addr->sa_family != AF_INET ||
			    !(ifa->ifa_flags & IFF_BROADCAST) ||
			    !(ifa->ifa_flags & IFF_UP) ||
			    ifa->ifa_broadaddr == NULL ||
			    ifa->ifa_broadaddr->sa_family != AF_INET)
				continue;
			sin = (struct sockaddr_in *)ifa->ifa_broadaddr;
			baddr.sin_addr = sin->sin_addr;

			/* use protocol 2 or 3 depending on i (odd or even) */
			if (i & 1) {
				if (sendto(sock[0], buf[0], outlen[0], 0,
				    (struct sockaddr *)&baddr,
				    sizeof(struct sockaddr)) != outlen[0])
					err(1, "can't send broadcast packet");
			} else {
				if (sendto(sock[1], buf[1], outlen[1], 0,
				    (struct sockaddr *)&baddr,
				    sizeof(struct sockaddr)) != outlen[1])
					err(1, "can't send broadcast packet");
			}
		}

		/*
		 * We stay in the select loop for ~5 seconds
		 */
		timeout.it_value.tv_sec = 5;
		timeout.it_value.tv_usec = 0;
		while (timerisset(&timeout.it_value)) {
			FD_SET(sock[0], fds);
			FD_SET(sock[1], fds);
			setitimer(ITIMER_REAL, &timeout, NULL);
			rval = select(maxfd, fds, NULL, NULL, NULL);
			setitimer(ITIMER_REAL, NULL, &timeout);
			if (rval == -1) {
				if (errno == EINTR)
					break;
				err(1, "select");	/* shouldn't happen */
			}
			if (FD_ISSET(sock[1], fds)) {
				stat = get_reply(sock[1], (in_port_t)port[1],
				    xid[1], &msg[1], &res[1], rusers_reply_3);
				if (stat != RPC_SUCCESS)
					goto cleanup;
			}
			if (FD_ISSET(sock[0], fds)) {
				stat = get_reply(sock[0], (in_port_t)port[0],
				    xid[0], &msg[0], &res[0], rusers_reply);
				if (stat != RPC_SUCCESS)
					goto cleanup;
			}
		}
	}
cleanup:
	if (ifap != NULL)
		freeifaddrs(ifap);
	if (fds != NULL)
		free(fds);
	if (sock[0] >= 0)
		(void)close(sock[0]);
	if (sock[1] >= 0)
		(void)close(sock[1]);
	AUTH_DESTROY(unix_auth);
	if (stat != RPC_SUCCESS) {
		clnt_perrno(stat);
		exit(1);
	}
}

void
print_entry(struct host_info *entry, int longfmt)
{
	char date[32], idle_time[64];
	char remote[RUSERS_MAXHOSTLEN + 3];
	struct rusers_utmp *ut;
	int i, len;

	if (!longfmt)
		printf("%-*.*s ", HOST_WIDTH, HOST_WIDTH, entry->host);

	for (i = 0, ut = entry->users; i < entry->count; i++, ut++) {
		if (longfmt) {
			strftime(date, sizeof(date), "%h %d %R",
			    localtime((time_t *)&ut->ut_time));
			date[sizeof(date) - 1] = '\0';
			fmt_idle(ut->ut_idle, idle_time, sizeof(idle_time));
			len = termwidth -
			    (MAX(strlen(ut->ut_user), NAME_WIDTH) + 1 +
			    HOST_WIDTH + 1 + LINE_WIDTH + 1 + strlen(date) +
			    1 + MAX(8, strlen(idle_time)) + 1 + 2);
			if (len > 0 && ut->ut_host[0] != '\0')
				snprintf(remote, sizeof(remote), "(%.*s)",
				    MIN(len, RUSERS_MAXHOSTLEN), ut->ut_host);
			else
				remote[0] = '\0';
			len = HOST_WIDTH - MIN(HOST_WIDTH, strlen(entry->host)) +
			    LINE_WIDTH - MIN(LINE_WIDTH, strlen(ut->ut_line));
			printf("%-*s %.*s:%.*s%-*s %-12s %8s %s\n",
			    NAME_WIDTH, ut->ut_user, HOST_WIDTH, entry->host,
			    LINE_WIDTH, ut->ut_line, len, "", date,
			    idle_time, remote);
		} else {
			fputs(ut->ut_user, stdout);
			putchar(' ');
		}
	}
	if (!longfmt)
		putchar('\n');
}

void
expandhosts(void)
{
	struct host_info *new_hostinfo, *entry;
	u_int count;
	int i, j;

	for (i = 0, count = 0; i < nentries; i++)
		count += hostinfo[i].count;

	new_hostinfo = (struct host_info *)calloc(sizeof(*entry), count);
	if (new_hostinfo == NULL)
		err(1, NULL);
	for (i = 0, entry = new_hostinfo; i < nentries; i++) {
		for (j = 0; j < hostinfo[i].count; j++) {
			memcpy(entry, &hostinfo[i], sizeof(*entry));
			entry->users = &hostinfo[i].users[j];
			entry->idle = entry->users->ut_idle;
			entry->count = 1;
			entry++;
		}
	}
	free(hostinfo);
	hostinfo = new_hostinfo;
	nentries = maxentries = count;
}

void
sorthosts(void)
{
	int i;
	int (*compar)(const void *, const void *);

	if (iflag && lflag)
		expandhosts();

	if (hflag)
		compar = hcompare;
	else if (iflag)
		compar = icompare;
	else
		compar = ucompare;
	qsort(hostinfo, nentries, sizeof(*hostinfo), compar);

	for (i = 0; i < nentries; i++)
		print_entry(&hostinfo[i], lflag && hostinfo[i].count);
}

int
hcompare(const void *aa, const void *bb)
{
	const struct host_info *a = (struct host_info *)aa;
	const struct host_info *b = (struct host_info *)bb;
	int rval;

	if ((rval = strcasecmp(a->host, b->host)) != 0)
		return(rval);

	if (a->idle < b->idle)
		return(-1);
	else if (a->idle > b->idle)
		return(1);

	if (a->count > b->count)
		return(-1);
	else if (a->count < b->count)
		return(1);

	return(0);
}

int
icompare(const void *aa, const void *bb)
{
	const struct host_info *a = (struct host_info *)aa;
	const struct host_info *b = (struct host_info *)bb;

	if (a->idle < b->idle)
		return(-1);
	else if (a->idle > b->idle)
		return(1);

	if (a->count > b->count)
		return(-1);
	else if (a->count < b->count)
		return(1);

	return(strcasecmp(a->host, b->host));
}

int
ucompare(const void *aa, const void *bb)
{
	const struct host_info *a = (struct host_info *)aa;
	const struct host_info *b = (struct host_info *)bb;

	if (a->count > b->count)
		return(-1);
	else if (a->count < b->count)
		return(1);

	if (a->idle < b->idle)
		return(-1);
	else if (a->idle > b->idle)
		return(1);

	return(strcasecmp(a->host, b->host));
}

void
alarmclock(int signo)
{

	;		/* just interrupt */
}

char *
estrndup(const char *src, size_t len)
{
	char *dst, *end;

	if ((end = memchr(src, '\0', len)) != NULL)
		len = end - src;

	if ((dst = malloc(len + 1)) == NULL)
		err(1, NULL);
	memcpy(dst, src, len);
	dst[len] = '\0';

	return(dst);
}

void
usage(void)
{

	fprintf(stderr, "usage: %s [-al] [-h | -i | -u] [hosts ...]\n",
	    __progname);
	exit(1);
}