bin/logname/logname.c

   1 /*      $OpenBSD: logname.c,v 1.10 2016/10/13 11:51:02 schwarze Exp $   */
   2 /*      $NetBSD: logname.c,v 1.6 1994/12/22 06:39:32 jtc Exp $  */
   3
   4 /*-
   5  * Copyright (c) 1991, 1993, 1994
   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 #include <err.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <unistd.h>
  37
  38 static void __dead
  39 usage(void)
  40 {
  41         (void)fprintf(stderr, "usage: logname\n");
  42         exit(1);
  43 }
  44
  45 int
  46 main(int argc, char *argv[])
  47 {
  48         int ch;
  49         char *p;
  50
  51         if (pledge("stdio", NULL) == -1)
  52                 err(1, "pledge");
  53
  54         while ((ch = getopt(argc, argv, "")) != -1)
  55                 switch (ch) {
  56                 default:
  57                         usage();
  58                 }
  59
  60         if (argc != optind)
  61                 usage();
  62
  63         if ((p = getlogin()) == NULL)
  64                 err(1, NULL);
  65
  66         (void)printf("%s\n", p);
  67         return 0;
  68 }