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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)fflush.c 8.1 (Berkeley) 6/4/93"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <errno.h> 45 #include <stdio.h> 46 #include "un-namespace.h" 47 #include "libc_private.h" 48 #include "local.h" 49 50 static int sflush_locked(FILE *); 51 52 /* 53 * Flush a single file, or (if fp is NULL) all files. 54 * MT-safe version 55 */ 56 int 57 fflush(FILE *fp) 58 { 59 int retval; 60 61 if (fp == NULL) 62 return (_fwalk(sflush_locked)); 63 FLOCKFILE(fp); 64 65 /* 66 * There is disagreement about the correct behaviour of fflush() 67 * when passed a file which is not open for reading. According to 68 * the ISO C standard, the behaviour is undefined. 69 * Under linux, such an fflush returns success and has no effect; 70 * under Windows, such an fflush is documented as behaving instead 71 * as fpurge(). 72 * Given that applications may be written with the expectation of 73 * either of these two behaviours, the only safe (non-astonishing) 74 * option is to return EBADF and ask that applications be fixed. 75 */ 76 if ((fp->_flags & (__SWR | __SRW)) == 0) { 77 errno = EBADF; 78 retval = EOF; 79 } else 80 retval = __sflush(fp); 81 FUNLOCKFILE(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 errno = EBADF; 98 retval = EOF; 99 } else 100 retval = __sflush(fp); 101 return (retval); 102 } 103 104 int 105 __sflush(FILE *fp) 106 { 107 unsigned char *p; 108 int n, t; 109 110 t = fp->_flags; 111 if ((t & __SWR) == 0) 112 return (0); 113 114 if ((p = fp->_bf._base) == NULL) 115 return (0); 116 117 n = fp->_p - p; /* write this much */ 118 119 /* 120 * Set these immediately to avoid problems with longjmp and to allow 121 * exchange buffering (via setvbuf) in user write function. 122 */ 123 fp->_p = p; 124 fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size; 125 126 for (; n > 0; n -= t, p += t) { 127 t = _swrite(fp, (char *)p, n); 128 if (t <= 0) { 129 fp->_flags |= __SERR; 130 return (EOF); 131 } 132 } 133 return (0); 134 } 135 136 static int 137 sflush_locked(FILE *fp) 138 { 139 int ret; 140 141 FLOCKFILE(fp); 142 ret = __sflush(fp); 143 FUNLOCKFILE(fp); 144 return (ret); 145 } 146