1 /* $OpenBSD: users.c,v 1.7 2003/06/03 02:56:21 millert Exp $ */ 2 /* $NetBSD: users.c,v 1.5 1994/12/20 15:58:19 jtc Exp $ */ 3 4 /* 5 * Copyright (c) 1980, 1987, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 static char copyright[] = 35 "@(#) Copyright (c) 1980, 1987, 1993\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #ifndef lint 40 #if 0 41 static char sccsid[] = "@(#)users.c 8.1 (Berkeley) 6/6/93"; 42 #endif 43 static char rcsid[] = "$OpenBSD: users.c,v 1.7 2003/06/03 02:56:21 millert Exp $"; 44 #endif /* not lint */ 45 46 #include <sys/types.h> 47 #include <utmp.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <err.h> 52 53 typedef char namebuf[UT_NAMESIZE]; 54 55 int scmp(const void *, const void *); 56 57 int 58 main(int argc, char *argv[]) 59 { 60 namebuf *names = NULL; 61 int ncnt = 0; 62 int nmax = 0; 63 int cnt; 64 struct utmp utmp; 65 int ch; 66 67 while ((ch = getopt(argc, argv, "")) != -1) 68 switch(ch) { 69 case '?': 70 default: 71 (void)fprintf(stderr, "usage: users\n"); 72 exit(1); 73 } 74 argc -= optind; 75 argv += optind; 76 77 if (!freopen(_PATH_UTMP, "r", stdin)) { 78 err(1, "can't open %s", _PATH_UTMP); 79 /* NOTREACHED */ 80 } 81 82 while (fread((char *)&utmp, sizeof(utmp), 1, stdin) == 1) { 83 if (*utmp.ut_name) { 84 if (ncnt >= nmax) { 85 nmax += 32; 86 names = realloc(names, 87 sizeof (*names) * nmax); 88 89 if (!names) { 90 err(1, NULL); 91 /* NOTREACHED */ 92 } 93 } 94 95 (void)strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE); 96 ++ncnt; 97 } 98 } 99 100 if (ncnt) { 101 qsort(names, ncnt, UT_NAMESIZE, scmp); 102 (void)printf("%.*s", UT_NAMESIZE, names[0]); 103 for (cnt = 1; cnt < ncnt; ++cnt) 104 if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE)) 105 (void)printf(" %.*s", UT_NAMESIZE, names[cnt]); 106 (void)printf("\n"); 107 } 108 exit(0); 109 } 110 111 int 112 scmp(const void *p, const void *q) 113 { 114 return(strncmp((char *) p, (char *) q, UT_NAMESIZE)); 115 } 116