gets.c revision 1.4 
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * 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. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38/*static char *sccsid = "from: @(#)gets.c	5.3 (Berkeley) 1/20/91";*/
39static char *rcsid = "$Id: gets.c,v 1.4 1994/04/24 01:01:29 mycroft Exp $";
40#endif /* LIBC_SCCS and not lint */
41
42#include <unistd.h>
43#include <stdio.h>
44#include <sys/uio.h>
45
46char *
47gets(buf)
48	char *buf;
49{
50	register int c;
51	register char *s;
52	static int warned;
53	static char w[] =
54	    ": warning: this program uses gets(), which is unsafe.\r\n";
55
56	if (!warned) {
57		struct iovec iov[2];
58		extern char *__progname;	/* in crt0 */
59
60		iov[0].iov_base = __progname;
61		iov[0].iov_len = strlen(__progname);
62		iov[1].iov_base = w;
63		iov[1].iov_len = strlen(w);
64		(void) writev(STDERR_FILENO, iov, 2);
65		warned = 1;
66	}
67
68	for (s = buf; (c = getchar()) != '\n';)
69		if (c == EOF)
70			if (s == buf)
71				return (NULL);
72			else
73				break;
74		else
75			*s++ = c;
76	*s = 0;
77	return (buf);
78}
79