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