lib/libc/stdio/gets.c

   1 /*      $NetBSD: gets.c,v 1.16 2007/06/03 17:39:26 christos Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 #if 0
  38 static char sccsid[] = "@(#)gets.c      8.1 (Berkeley) 6/4/93";
  39 #else
  40 __RCSID("$NetBSD: gets.c,v 1.16 2007/06/03 17:39:26 christos Exp $");
  41 #endif
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include <assert.h>
  45 #include <errno.h>
  46 #include <stdio.h>
  47 #include "reentrant.h"
  48 #include "local.h"
  49 #ifdef _FORTIFY_SOURCE
  50 #undef gets
  51 #endif
  52
  53 __warn_references(gets, "warning: this program uses gets(), which is unsafe.")
  54
  55 char *
  56 gets(buf)
  57         char *buf;
  58 {
  59         int c;
  60         char *s;
  61
  62         _DIAGASSERT(buf != NULL);
  63
  64         FLOCKFILE(stdin);
  65         for (s = buf; (c = getchar_unlocked()) != '\n'; ) {
  66                 if (c == EOF) {
  67                         if (s == buf) {
  68                                 FUNLOCKFILE(stdin);
  69                                 return (NULL);
  70                         } else {
  71                                 break;
  72                         }
  73                 } else {
  74                         *s++ = c;
  75                 }
  76         }
  77         *s = 0;
  78         FUNLOCKFILE(stdin);
  79         return (buf);
  80 }