1 /* $NetBSD: fflush.c,v 1.18 2012/03/27 15:05:42 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)fflush.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: fflush.c,v 1.18 2012/03/27 15:05:42 christos Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <stddef.h> 45 #include <assert.h> 46 #include <errno.h> 47 #include <stdio.h> 48 #include "reentrant.h" 49 #include "local.h" 50 51 #ifdef _REENTRANT 52 extern rwlock_t __sfp_lock; 53 #endif 54 55 /* Flush a single file, or (if fp is NULL) all files. */ 56 int 57 fflush(FILE *fp) 58 { 59 int r; 60 61 if (fp == NULL) { 62 rwlock_rdlock(&__sfp_lock); 63 r = _fwalk(__sflush); 64 rwlock_unlock(&__sfp_lock); 65 return r; 66 } 67 68 FLOCKFILE(fp); 69 if ((fp->_flags & (__SWR | __SRW)) == 0) { 70 errno = EBADF; 71 r = EOF; 72 } else { 73 r = __sflush(fp); 74 } 75 FUNLOCKFILE(fp); 76 return r; 77 } 78 79 int 80 __sflush(FILE *fp) 81 { 82 unsigned char *p; 83 size_t n; 84 ssize_t t; 85 86 _DIAGASSERT(fp != NULL); 87 88 t = fp->_flags; 89 if ((t & __SWR) == 0) 90 return 0; 91 92 if ((p = fp->_bf._base) == NULL) 93 return 0; 94 95 ptrdiff_t tp = fp->_p - p; 96 _DIAGASSERT(__type_fit(ssize_t, tp)); 97 n = (ssize_t)tp; /* write this much */ 98 99 /* 100 * Set these immediately to avoid problems with longjmp and to allow 101 * exchange buffering (via setvbuf) in user write function. 102 */ 103 fp->_p = p; 104 fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size; 105 106 for (; n > 0; n -= t, p += t) { 107 t = (*fp->_write)(fp->_cookie, (char *)p, n); 108 if (t <= 0) { 109 fp->_flags |= __SERR; 110 return EOF; 111 } 112 } 113 if (fp->_flush) 114 return (*fp->_flush)(fp->_cookie); 115 return 0; 116 } 117