| | 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 | */ |
| | 32 | |
| | 33 | #if defined(LIBC_SCCS) && !defined(lint) |
| | 34 | static char sccsid[] = "@(#)fflush.c 8.1 (Berkeley) 6/4/93"; |
| | 35 | #endif /* LIBC_SCCS and not lint */ |
| | 36 | #include <sys/cdefs.h> |
| | 37 | __FBSDID("$FreeBSD: src/lib/libc/stdio/fflush.c,v 1.14 2007/01/09 00:28:06 imp Exp $"); |
| | 38 | |
| | 39 | #include "namespace.h" |
| | 40 | #include <errno.h> |
| | 41 | #include <stdio.h> |
| | 42 | #include <string.h> |
| | 43 | #include "un-namespace.h" |
| | 44 | #include "libc_private.h" |
| | 45 | #include "local.h" |
| | 46 | |
| | 47 | static int sflush_locked(FILE *); |
| | 48 | |
| | 49 | /* |
| | 50 | * Flush a single file, or (if fp is NULL) all files. |
| | 51 | * MT-safe version |
| | 52 | */ |
| | 53 | int |
| | 54 | fflush(FILE *fp) |
| | 55 | { |
| | 56 | int retval; |
| | 57 | |
| | 58 | if (fp == NULL) |
| | 59 | return (_fwalk(sflush_locked)); |
| | 60 | FLOCKFILE(fp); |
| | 61 | |
| | 62 | /* |
| | 63 | * 11103146: Conformance change: |
| | 64 | * --- Begin History --- |
| | 65 | * There is disagreement about the correct behaviour of fflush() |
| | 66 | * when passed a file which is not open for writing. According to |
| | 67 | * the ISO C standard, the behaviour is undefined. |
| | 68 | * Under linux, such an fflush returns success and has no effect; |
| | 69 | * under Windows, such an fflush is documented as behaving instead |
| | 70 | * as fpurge(). |
| | 71 | * Given that applications may be written with the expectation of |
| | 72 | * either of these two behaviours, the only safe (non-astonishing) |
| | 73 | * option is to return EBADF and ask that applications be fixed. |
| | 74 | * --- End History --- |
| | 75 | * SUSv3 now requires that fflush() returns success on a read-only |
| | 76 | * stream. In addition, the conformance tests will warn if a fflush |
| | 77 | * on a read-only stream does not set the file descriptor's file offset |
| | 78 | * to the real position. We won't be fixing the warning at this time. |
| | 79 | */ |
| | 80 | if ((fp->_flags & (__SWR | __SRW)) == 0) { |
| | 81 | retval = 0; |
| | 82 | } else |
| | 83 | retval = __sflush(fp); |
| | 84 | FUNLOCKFILE(fp); |
| | 85 | return (retval); |
| | 86 | } |
| | 87 | |
| | 88 | /* |
| | 89 | * Flush a single file, or (if fp is NULL) all files. |
| | 90 | * Non-MT-safe version |
| | 91 | */ |
| | 92 | int |
| | 93 | __fflush(FILE *fp) |
| | 94 | { |
| | 95 | int retval; |
| | 96 | |
| | 97 | if (fp == NULL) |
| | 98 | return (_fwalk(sflush_locked)); |
| | 99 | if ((fp->_flags & (__SWR | __SRW)) == 0) { |
| | 100 | retval = 0; |
| | 101 | } else |
| | 102 | retval = __sflush(fp); |
| | 103 | return (retval); |
| | 104 | } |
| | 105 | |
| | 106 | int |
| | 107 | __sflush(FILE *fp) |
| | 108 | { |
| | 109 | unsigned char *p; |
| | 110 | int n, t; |
| | 111 | |
| | 112 | t = fp->_flags; |
| | 113 | if ((t & __SWR) == 0) |
| | 114 | return (0); |
| | 115 | |
| | 116 | if ((p = fp->_bf._base) == NULL) |
| | 117 | return (0); |
| | 118 | |
| | 119 | n = fp->_p - p; /* write this much */ |
| | 120 | |
| | 121 | /* |
| | 122 | * Set these immediately to avoid problems with longjmp and to allow |
| | 123 | * exchange buffering (via setvbuf) in user write function. |
| | 124 | */ |
| | 125 | fp->_p = p; |
| | 126 | fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size; |
| | 127 | |
| | 128 | for (; n > 0; n -= t, p += t) { |
| | 129 | t = _swrite(fp, (char *)p, n); |
| | 130 | if (t <= 0) { |
| | 131 | /* 5340694: reset _p and _w on EAGAIN */ |
| | 132 | if (t < 0 && errno == EAGAIN) { |
| | 133 | if (p > fp->_p) /* some was written */ |
| | 134 | memmove(fp->_p, p, n); |
| | 135 | fp->_p += n; |
| | 136 | if (!(fp->_flags & (__SLBF|__SNBF))) |
| | 137 | fp->_w -= n; |
| | 138 | } |
| | 139 | fp->_flags |= __SERR; |
| | 140 | return (EOF); |
| | 141 | } |
| | 142 | } |
| | 143 | return (0); |
| | 144 | } |
| | 145 | |
| | 146 | static int |
| | 147 | sflush_locked(FILE *fp) |
| | 148 | { |
| | 149 | int ret; |
| | 150 | |
| | 151 | FLOCKFILE(fp); |
| | 152 | ret = __sflush(fp); |
| | 153 | FUNLOCKFILE(fp); |
| | 154 | return (ret); |
| | 155 | } |
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