xref: /netbsd-src/lib/libc/stdio/fgetstr.c (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad)
1 /* $NetBSD: fgetstr.c,v 1.10 2009/12/02 09:03:13 roy Exp $	*/
2 
3 /*
4  * Copyright (c) 2009 The NetBSD Foundation, Inc.
5  *
6  * This code is derived from software contributed to The NetBSD Foundation
7  * by Roy Marples.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __RCSID("$NetBSD: fgetstr.c,v 1.10 2009/12/02 09:03:13 roy Exp $");
32 
33 #include "namespace.h"
34 
35 #include <assert.h>
36 #include <errno.h>
37 #include <limits.h>
38 #include <stdio.h>
39 
40 #include "reentrant.h"
41 #include "local.h"
42 
43 /*
44  * Get an input line.
45  * This now uses getdelim(3) for a code reduction.
46  * The upside is that strings are now always NULL terminated, but relying
47  * on this is non portable - better to use the POSIX getdelim(3) function.
48  */
49 char *
50 __fgetstr(FILE *__restrict fp, size_t *__restrict lenp, int sep)
51 {
52 	char *p;
53 	size_t size;
54 	ssize_t n;
55 
56 	_DIAGASSERT(fp != NULL);
57 	_DIAGASSERT(lenp != NULL);
58 
59 	p = (char *)fp->_lb._base;
60 	size = fp->_lb._size;
61 	n = __getdelim(&p, &size, sep, fp);
62 	fp->_lb._base = (unsigned char *)p;
63 	/* The struct size variable is only an int .....
64 	 * This still works when exceeded, but the buffer could be
65 	 * realloced needlessly. */
66 	if (size > INT_MAX)
67 		fp->_lb._size = INT_MAX;
68 	else
69 		fp->_lb._size = (int)size;
70 	if (n == -1) {
71 		*lenp = 0;
72 		if (__sferror(fp) && errno == EOVERFLOW) /* fixup errno */
73 			errno = EINVAL;
74 		return NULL;
75 	}
76 	*lenp = n;
77 	return p;
78 }
79