users.c revision 202200
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 202200 2010-01-13 18:09:54Z ed $"; 46#endif /* not lint */ 47 48#include <sys/param.h> 49#include <sys/types.h> 50#include <err.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55#include <utmpx.h> 56 57typedef char namebuf[MAXLOGNAME]; 58 59int scmp(const void *, const void *); 60static void usage(void); 61 62int 63main(int argc, char **argv) 64{ 65 namebuf *names = NULL; 66 int ncnt = 0; 67 int nmax = 0; 68 int cnt; 69 struct utmpx *ut; 70 int ch; 71 72 while ((ch = getopt(argc, argv, "")) != -1) 73 switch(ch) { 74 case '?': 75 default: 76 usage(); 77 } 78 argc -= optind; 79 argv += optind; 80 81 setutxent(); 82 while ((ut = getutxent()) != NULL) { 83 if (ut->ut_type != USER_PROCESS) 84 continue; 85 if (ncnt >= nmax) { 86 nmax += 32; 87 names = realloc(names, sizeof(*names) * nmax); 88 if (!names) { 89 errx(1, "realloc"); 90 /* NOTREACHED */ 91 } 92 } 93 (void)strlcpy(names[ncnt], ut->ut_user, sizeof(*names)); 94 ++ncnt; 95 } 96 endutxent(); 97 if (ncnt > 0) { 98 qsort(names, ncnt, sizeof(namebuf), scmp); 99 (void)printf("%s", names[0]); 100 for (cnt = 1; cnt < ncnt; ++cnt) 101 if (strcmp(names[cnt], names[cnt - 1]) != 0) 102 (void)printf(" %s", names[cnt]); 103 (void)printf("\n"); 104 } 105 exit(0); 106} 107 108static void 109usage(void) 110{ 111 (void)fprintf(stderr, "usage: users\n"); 112 exit(1); 113} 114 115int 116scmp(const void *p, const void *q) 117{ 118 119 return (strcmp(p, q)); 120} 121