1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*	Copyright (c) 1988 AT&T	*/
28/*	  All Rights Reserved  	*/
29
30#pragma ident	"%Z%%M%	%I%	%E% SMI"
31
32
33#pragma weak __filbuf = _filbuf
34
35#include "lint.h"
36#include "file64.h"
37#include <stdio.h>
38#include <errno.h>
39#include <sys/types.h>
40#include <unistd.h>
41#include "stdiom.h"
42
43
44static int
45_xpg4_check(void)
46{
47	extern int	__xpg4;
48
49	return (__xpg4);
50}
51
52/* fill buffer, return first character or EOF */
53int
54_filbuf(FILE *iop)
55{
56	ssize_t res;
57	size_t nbyte;
58	Uchar *endbuf;
59#ifdef	_LP64
60	unsigned int	flag;
61#else
62	unsigned char	flag;
63#endif
64
65	if (!(iop->_flag & _IOREAD))	/* check, correct permissions */
66	{
67		if (iop->_flag & _IORW)
68			iop->_flag |= _IOREAD; /* change direction */
69						/* to read - fseek */
70		else {
71			errno = EBADF;
72			return (EOF);
73		}
74	}
75
76	if (iop->_base == 0) {
77		if ((endbuf = _findbuf(iop)) == 0) /* get buffer and */
78						/* end_of_buffer */
79			return (EOF);
80	}
81	else
82		endbuf = _bufend(iop);
83
84	/*
85	 * Flush all line-buffered streams before we
86	 * read no-buffered or line-buffered input.
87	 */
88	if (iop->_flag & (_IONBF | _IOLBF))
89		_flushlbf();
90	/*
91	 * Changed the get family fns in Solaris 10 to comply with the
92	 * 1990 C Standard and standards based upon it.  If the
93	 * end-of-file indicator for the stream is set, or if the stream
94	 * is at end-of-file, the function will return EOF, and the file
95	 * position indicator for the stream will not be advanced.
96	 * Additional bytes appended to the file do not clear the EOF
97	 * indicator.
98	 */
99	if ((flag = iop->_flag) & _IOEOF) {
100		if (_xpg4_check()) {
101			/*
102			 * A previous read() has returned 0 (below),
103			 * therefore iop->_cnt was set to 0, and the EOF
104			 * indicator was set before returning EOF.  Reset
105			 * iop->_cnt to 0; it has likely been changed by
106			 * a function such as getc().
107			 */
108			iop->_cnt = 0;
109			return (EOF);
110		}
111	}
112	/*
113	 * Fill buffer or read 1 byte for unbuffered, handling any errors.
114	 */
115	iop->_ptr = iop->_base;
116	if (flag & _IONBF)
117		nbyte = 1;
118	else
119		nbyte = endbuf - iop->_base;
120	if ((res = read(GET_FD(iop), (char *)iop->_base, nbyte)) > 0) {
121		iop->_cnt = res - 1;
122		return (*iop->_ptr++);
123	}
124
125	iop->_cnt = 0;
126	if (res == 0)
127		iop->_flag |= _IOEOF;
128	else if (!cancel_active())
129		iop->_flag |= _IOERR;
130	return (EOF);
131}
132