users.c revision 102944
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 const 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 41#if 0 42static char sccsid[] = "@(#)users.c 8.1 (Berkeley) 6/6/93"; 43#endif 44static const char rcsid[] = 45 "$FreeBSD: head/usr.bin/users/users.c 102944 2002-09-04 23:29:10Z dwmalone $"; 46#endif /* not lint */ 47 48#include <sys/types.h> 49#include <err.h> 50#include <stdio.h> 51#include <stdlib.h> 52#include <string.h> 53#include <unistd.h> 54#include <utmp.h> 55 56typedef char namebuf[UT_NAMESIZE]; 57 58int scmp(const void *, const void *); 59static void usage(void); 60 61int 62main(int argc, char **argv) 63{ 64 namebuf *names = NULL; 65 int ncnt = 0; 66 int nmax = 0; 67 int cnt; 68 struct utmp utmp; 69 int ch; 70 71 while ((ch = getopt(argc, argv, "")) != -1) 72 switch(ch) { 73 case '?': 74 default: 75 usage(); 76 } 77 argc -= optind; 78 argv += optind; 79 80 if (!freopen(_PATH_UTMP, "r", stdin)) 81 errx(1, "can't open %s", _PATH_UTMP); 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, sizeof (*names) * nmax); 87 if (!names) { 88 errx(1, "realloc"); 89 /* NOTREACHED */ 90 } 91 } 92 (void)strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE); 93 ++ncnt; 94 } 95 } 96 if (ncnt) { 97 qsort(names, ncnt, UT_NAMESIZE, scmp); 98 (void)printf("%.*s", UT_NAMESIZE, names[0]); 99 for (cnt = 1; cnt < ncnt; ++cnt) 100 if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE)) 101 (void)printf(" %.*s", UT_NAMESIZE, names[cnt]); 102 (void)printf("\n"); 103 } 104 exit(0); 105} 106 107static void 108usage(void) 109{ 110 (void)fprintf(stderr, "usage: users\n"); 111 exit(1); 112} 113 114int 115scmp(const void *p, const void *q) 116{ 117 return(strncmp(p, q, UT_NAMESIZE)); 118} 119