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      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 
     44 static int
     45 _xpg4_check(void)
     46 {
     47 	extern int	__xpg4;
     48 
     49 	return (__xpg4);
     50 }
     51 
     52 /* fill buffer, return first character or EOF */
     53 int
     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