/*
 * Copyright (c) 1980, 1987, 1993
 *      The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * @(#) Copyright (c) 1980, 1987, 1993 The Regents of the University of California.  All rights reserved.
 * @(#)users.c  8.1 (Berkeley) 6/6/93
 * $FreeBSD: src/usr.bin/users/users.c,v 1.8 2002/09/04 23:29:09 dwmalone Exp $
 * $DragonFly: src/usr.bin/users/users.c,v 1.5 2007/10/02 16:38:10 swildner Exp $
 */

#include <sys/types.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "utmpentry.h"

typedef char   namebuf[32];

static int scmp(const void *, const void *);
static void usage(void);

int
main(int argc, char **argv)
{
        struct utmpentry *ep = NULL;    /* avoid gcc warnings */
        namebuf *names = NULL;
        int ncnt = 0;
        int nmax = 0;
        int cnt;
        int ch;

        while ((ch = getopt(argc, argv, "")) != -1) {
                switch(ch) {
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        getutentries(NULL, &ep);
        for (; ep; ep = ep->next) {
                if (ncnt >= nmax) {
                        nmax += 32;
                        names = realloc(names,
                                sizeof (*names) * nmax);
                        if (names == NULL)
                                err(1, "realloc");
                }
                strcpy(names[ncnt], ep->name);
                ++ncnt;
        }
        if (ncnt) {
                qsort(names, ncnt, 32, scmp);
                printf("%.*s", 32, names[0]);
                for (cnt = 1; cnt < ncnt; ++cnt) {
                        if (strcmp(names[cnt], names[cnt - 1]))
                                printf(" %.*s", 32, names[cnt]);
                }
                printf("\n");
        }
        exit(0);
}

static void
usage(void)
{
        fprintf(stderr, "usage: users\n");
        exit(1);
}
        
int
scmp(const void *p, const void *q)
{
        return(strncmp(p, q, 32));
}