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  * 4. 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  * © Portions copyright (c) 2005-2006  Nokia Corporation.  All rights reserved.

    32  */

    33 

    34 #if defined(LIBC_SCCS) && !defined(lint)

    35 static char sccsid[] = "@(#)fflush.c	8.1 (Berkeley) 6/4/93";

    36 #endif /* LIBC_SCCS and not lint */

    37 #include <sys/cdefs.h>

    38 #ifndef __SYMBIAN32__

    39 __FBSDID("$FreeBSD: src/lib/libc/stdio/fflush.c,v 1.13 2004/07/04 20:17:00 cperciva Exp $");

    40 #endif

    41 #include "namespace.h"

    42 #include <errno.h>

    43 #include <stdio.h>

    44 #include "un-namespace.h"

    45 #include "libc_private.h"

    46 #include "local.h"

    47 

    48 static int	sflush_locked(FILE *);

    49 

    50 /*

    51  * Flush a single file, or (if fp is NULL) all files.

    52  * MT-safe version

    53  */

    54 EXPORT_C int

    55 fflush(FILE *fp)

    56 {

    57 	int retval;

    58 

    59 	if (fp == NULL)

    60 		return (_fwalk(sflush_locked));

    61 	FLOCKFILE(fp);

    62 

    63 	/*

    64 	 * There is disagreement about the correct behaviour of fflush()

    65 	 * when passed a file which is not open for reading.  According to

    66 	 * the ISO C standard, the behaviour is undefined.

    67 	 * Under linux, such an fflush returns success and has no effect;

    68 	 * under Windows, such an fflush is documented as behaving instead

    69 	 * as fpurge().

    70 	 * Given that applications may be written with the expectation of

    71 	 * either of these two behaviours, the only safe (non-astonishing)

    72 	 * option is to return EBADF and ask that applications be fixed.

    73 	 */

    74 	if ((fp->_flags & (__SWR | __SRW)) == 0) {

    75 		errno = EBADF;

    76 		retval = EOF;

    77 	} else

    78 		retval = __sflush(fp);

    79 	FUNLOCKFILE(fp);

    80 	return (retval);

    81 }

    82 

    83 /*

    84  * Flush a single file, or (if fp is NULL) all files.

    85  * Non-MT-safe version

    86  */

    87 int

    88 __fflush(FILE *fp)

    89 {

    90 	int retval;

    91 

    92 	if (fp == NULL)

    93 		return (_fwalk(sflush_locked));

    94 	if ((fp->_flags & (__SWR | __SRW)) == 0) {

    95 		errno = EBADF;

    96 		retval = EOF;

    97 	} else

    98 		retval = __sflush(fp);

    99 	return (retval);

   100 }

   101 

   102 int

   103 __sflush(FILE *fp)

   104 {

   105 	unsigned char *p;

   106 	int n, t;

   107 

   108 	t = fp->_flags;

   109 	if ((t & __SWR) == 0)

   110 		return (0);

   111 

   112 	if ((p = fp->_bf._base) == NULL)

   113 		return (0);

   114 

   115 	n = fp->_p - p;		/* write this much */

   116 

   117 	/*

   118 	 * Set these immediately to avoid problems with longjmp and to allow

   119 	 * exchange buffering (via setvbuf) in user write function.

   120 	 */

   121 	fp->_p = p;

   122 	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;

   123 

   124 	for (; n > 0; n -= t, p += t) {

   125 		t = _swrite(fp, (char *)p, n);

   126 		if (t <= 0) {

   127 			fp->_flags |= __SERR;

   128 			return (EOF);

   129 		}

   130 	}

   131 	return (0);

   132 }

   133 

   134 static int

   135 sflush_locked(FILE *fp)

   136 {

   137 	int	ret;

   138 

   139 	FLOCKFILE(fp);

   140 	ret = __sflush(fp);

   141 	FUNLOCKFILE(fp);

   142 	return (ret);

   143 }