xref: /freebsd/lib/libc/stdio/gets.c (revision ea825d02749f382c3f7e17f28247f20a48733eab)
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)
34 static char sccsid[] = "@(#)gets.c	8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include "namespace.h"
40 #include <unistd.h>
41 #include <stdio.h>
42 #include "un-namespace.h"
43 #include "libc_private.h"
44 #include "local.h"
45 
46 __warn_references(gets, "warning: this program uses gets(), which is unsafe.");
47 
48 char *
49 gets(char *buf)
50 {
51 	int c;
52 	char *s, *ret;
53 	static int warned;
54 	static const char w[] =
55 	    "warning: this program uses gets(), which is unsafe.\n";
56 
57 	FLOCKFILE_CANCELSAFE(stdin);
58 	ORIENT(stdin, -1);
59 	if (!warned) {
60 		(void) _write(STDERR_FILENO, w, sizeof(w) - 1);
61 		warned = 1;
62 	}
63 	for (s = buf; (c = __sgetc(stdin)) != '\n'; ) {
64 		if (c == EOF)
65 			if (s == buf) {
66 				ret = NULL;
67 				goto end;
68 			} else
69 				break;
70 		else
71 			*s++ = c;
72 	}
73 	*s = 0;
74 	ret = buf;
75 end:
76 	FUNLOCKFILE_CANCELSAFE();
77 	return (ret);
78 }
79