users.c revision 1591
1/* 2 * Copyright (c) 1980, 1987, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#ifndef lint 35static char copyright[] = 36"@(#) Copyright (c) 1980, 1987, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38#endif /* not lint */ 39 40#ifndef lint 41static char sccsid[] = "@(#)users.c 8.1 (Berkeley) 6/6/93"; 42#endif /* not lint */ 43 44#include <sys/types.h> 45#include <utmp.h> 46#include <stdio.h> 47 48#define MAXUSERS 200 49 50main(argc, argv) 51 int argc; 52 char **argv; 53{ 54 extern int optind; 55 register int cnt, ncnt; 56 struct utmp utmp; 57 char names[MAXUSERS][UT_NAMESIZE]; 58 int ch, scmp(); 59 60 while ((ch = getopt(argc, argv, "")) != EOF) 61 switch(ch) { 62 case '?': 63 default: 64 (void)fprintf(stderr, "usage: users\n"); 65 exit(1); 66 } 67 argc -= optind; 68 argv += optind; 69 70 if (!freopen(_PATH_UTMP, "r", stdin)) { 71 (void)fprintf(stderr, "users: can't open %s.\n", _PATH_UTMP); 72 exit(1); 73 } 74 for (ncnt = 0; 75 fread((char *)&utmp, sizeof(utmp), 1, stdin) == 1;) 76 if (*utmp.ut_name) { 77 if (ncnt == MAXUSERS) { 78 (void)fprintf(stderr, 79 "users: too many users.\n"); 80 break; 81 } 82 (void)strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE); 83 ++ncnt; 84 } 85 86 if (ncnt) { 87 qsort(names, ncnt, UT_NAMESIZE, scmp); 88 (void)printf("%.*s", UT_NAMESIZE, names[0]); 89 for (cnt = 1; cnt < ncnt; ++cnt) 90 if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE)) 91 (void)printf(" %.*s", UT_NAMESIZE, names[cnt]); 92 (void)printf("\n"); 93 } 94 exit(0); 95} 96 97scmp(p, q) 98 char *p, *q; 99{ 100 return(strncmp(p, q, UT_NAMESIZE)); 101} 102