gets.c revision 302408 
1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
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#if defined(LIBC_SCCS) && !defined(lint)
34static char sccsid[] = "@(#)gets.c	8.1 (Berkeley) 6/4/93";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD: stable/11/lib/libc/stdio/gets.c 268928 2014-07-20 20:29:28Z pfg $");
38
39#include "namespace.h"
40#include <unistd.h>
41#include <stdio.h>
42#include <sys/cdefs.h>
43#include "un-namespace.h"
44#include "libc_private.h"
45#include "local.h"
46
47__warn_references(gets, "warning: this program uses gets(), which is unsafe.");
48
49char *
50gets(char *buf)
51{
52	int c;
53	char *s;
54	static int warned;
55	static const char w[] =
56	    "warning: this program uses gets(), which is unsafe.\n";
57
58	FLOCKFILE(stdin);
59	ORIENT(stdin, -1);
60	if (!warned) {
61		(void) _write(STDERR_FILENO, w, sizeof(w) - 1);
62		warned = 1;
63	}
64	for (s = buf; (c = __sgetc(stdin)) != '\n';)
65		if (c == EOF)
66			if (s == buf) {
67				FUNLOCKFILE(stdin);
68				return (NULL);
69			} else
70				break;
71		else
72			*s++ = c;
73	*s = 0;
74	FUNLOCKFILE(stdin);
75	return (buf);
76}
77