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 * @(#) Copyright (c) 1980, 1987, 1993 The Regents of the University of California. All rights reserved. 34 * @(#)users.c 8.1 (Berkeley) 6/6/93 35 * $FreeBSD: src/usr.bin/users/users.c,v 1.8 2002/09/04 23:29:09 dwmalone Exp $ 36 * $DragonFly: src/usr.bin/users/users.c,v 1.5 2007/10/02 16:38:10 swildner Exp $ 37 */ 38 39 #include <sys/types.h> 40 #include <err.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 #include <utmp.h> 46 47 typedef char namebuf[UT_NAMESIZE]; 48 49 static int scmp(const void *, const void *); 50 static void usage(void); 51 52 int 53 main(int argc, char **argv) 54 { 55 namebuf *names = NULL; 56 int ncnt = 0; 57 int nmax = 0; 58 int cnt; 59 struct utmp utmp; 60 int ch; 61 62 while ((ch = getopt(argc, argv, "")) != -1) { 63 switch(ch) { 64 default: 65 usage(); 66 } 67 } 68 argc -= optind; 69 argv += optind; 70 71 if (!freopen(_PATH_UTMP, "r", stdin)) 72 err(1, "can't open %s", _PATH_UTMP); 73 while (fread((char *)&utmp, sizeof(utmp), 1, stdin) == 1) { 74 if (*utmp.ut_name) { 75 if (ncnt >= nmax) { 76 nmax += 32; 77 names = realloc(names, 78 sizeof (*names) * nmax); 79 if (names == NULL) 80 err(1, "realloc"); 81 } 82 strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE); 83 ++ncnt; 84 } 85 } 86 if (ncnt) { 87 qsort(names, ncnt, UT_NAMESIZE, scmp); 88 printf("%.*s", UT_NAMESIZE, names[0]); 89 for (cnt = 1; cnt < ncnt; ++cnt) { 90 if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE)) 91 printf(" %.*s", UT_NAMESIZE, names[cnt]); 92 } 93 printf("\n"); 94 } 95 exit(0); 96 } 97 98 static void 99 usage(void) 100 { 101 fprintf(stderr, "usage: users\n"); 102 exit(1); 103 } 104 105 int 106 scmp(const void *p, const void *q) 107 { 108 return(strncmp(p, q, UT_NAMESIZE)); 109 } 110