1 /* $NetBSD: users.c,v 1.9 1998/12/19 23:35:24 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1980, 1987, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 __COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"); 40 #endif /* not lint */ 41 42 #ifndef lint 43 #if 0 44 static char sccsid[] = "@(#)users.c 8.1 (Berkeley) 6/6/93"; 45 #endif 46 __RCSID("$NetBSD: users.c,v 1.9 1998/12/19 23:35:24 christos Exp $"); 47 #endif /* not lint */ 48 49 #include <sys/types.h> 50 51 #include <err.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <unistd.h> 55 #include <string.h> 56 #include <unistd.h> 57 #include <utmp.h> 58 59 typedef char namebuf[UT_NAMESIZE]; 60 61 int main __P((int, char **)); 62 int scmp __P((const void *, const void *)); 63 64 int 65 main(argc, argv) 66 int argc; 67 char **argv; 68 { 69 namebuf *names = NULL; 70 int ncnt = 0; 71 int nmax = 0; 72 int cnt; 73 struct utmp utmp; 74 int ch; 75 76 while ((ch = getopt(argc, argv, "")) != -1) 77 switch(ch) { 78 case '?': 79 default: 80 (void)fprintf(stderr, "usage: users\n"); 81 exit(1); 82 } 83 argc -= optind; 84 argv += optind; 85 86 if (!freopen(_PATH_UTMP, "r", stdin)) { 87 err(1, "can't open %s", _PATH_UTMP); 88 /* NOTREACHED */ 89 } 90 91 while (fread((char *)&utmp, sizeof(utmp), 1, stdin) == 1) { 92 if (*utmp.ut_name) { 93 if (ncnt >= nmax) { 94 nmax += 32; 95 names = realloc(names, 96 sizeof (*names) * nmax); 97 98 if (!names) { 99 err(1, "realloc"); 100 /* NOTREACHED */ 101 } 102 } 103 104 (void)strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE); 105 ++ncnt; 106 } 107 } 108 109 if (ncnt) { 110 qsort(names, ncnt, UT_NAMESIZE, scmp); 111 (void)printf("%.*s", (int)UT_NAMESIZE, names[0]); 112 for (cnt = 1; cnt < ncnt; ++cnt) 113 if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE)) 114 (void)printf(" %.*s", (int)UT_NAMESIZE, 115 names[cnt]); 116 (void)printf("\n"); 117 } 118 exit(0); 119 } 120 121 int 122 scmp(p, q) 123 const void *p, *q; 124 { 125 return(strncmp((char *) p, (char *) q, UT_NAMESIZE)); 126 } 127