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 * @(#)setvbuf.c 8.2 (Berkeley) 11/16/93 37 * $FreeBSD: src/lib/libc/stdio/setvbuf.c,v 1.7 1999/08/28 00:01:16 peter Exp $ 38 * $DragonFly: src/lib/libc/stdio/setvbuf.c,v 1.7 2005/11/20 11:07:30 swildner Exp $ 39 */ 40 41 #include "namespace.h" 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include "un-namespace.h" 45 46 #include "local.h" 47 #include "libc_private.h" 48 #include "priv_stdio.h" 49 50 /* 51 * Set one of the three kinds of buffering, optionally including 52 * a buffer. 53 */ 54 int 55 setvbuf(FILE *fp, char *buf, int mode, size_t size) 56 { 57 int ret, flags; 58 size_t iosize; 59 int ttyflag; 60 61 /* 62 * Verify arguments. The `int' limit on `size' is due to this 63 * particular implementation. Note, buf and size are ignored 64 * when setting _IONBF. 65 */ 66 if (mode != _IONBF) 67 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 68 return (EOF); 69 70 FLOCKFILE(fp); 71 /* 72 * Write current buffer, if any. Discard unread input (including 73 * ungetc data), cancel line buffering, and free old buffer if 74 * malloc()ed. We also clear any eof condition, as if this were 75 * a seek. 76 */ 77 ret = 0; 78 __sflush(fp); 79 if (HASUB(fp)) 80 FREEUB(fp); 81 fp->pub._r = fp->pub._lbfsize = 0; 82 flags = fp->pub._flags; 83 if (flags & __SMBF) 84 free((void *)fp->_bf._base); 85 flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); 86 87 /* If setting unbuffered mode, skip all the hard work. */ 88 if (mode == _IONBF) 89 goto nbf; 90 91 /* 92 * Find optimal I/O size for seek optimization. This also returns 93 * a `tty flag' to suggest that we check isatty(fd), but we do not 94 * care since our caller told us how to buffer. 95 */ 96 flags |= __swhatbuf(fp, &iosize, &ttyflag); 97 if (size == 0) { 98 buf = NULL; /* force local allocation */ 99 size = iosize; 100 } 101 102 /* Allocate buffer if needed. */ 103 if (buf == NULL) { 104 if ((buf = malloc(size)) == NULL) { 105 /* 106 * Unable to honor user's request. We will return 107 * failure, but try again with file system size. 108 */ 109 ret = EOF; 110 if (size != iosize) { 111 size = iosize; 112 buf = malloc(size); 113 } 114 } 115 if (buf == NULL) { 116 /* No luck; switch to unbuffered I/O. */ 117 nbf: 118 fp->pub._flags = flags | __SNBF; 119 fp->pub._w = 0; 120 fp->_bf._base = fp->pub._p = fp->_nbuf; 121 fp->_bf._size = 1; 122 FUNLOCKFILE(fp); 123 return (ret); 124 } 125 flags |= __SMBF; 126 } 127 128 /* 129 * Kill any seek optimization if the buffer is not the 130 * right size. 131 * 132 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? 133 */ 134 if (size != iosize) 135 flags |= __SNPT; 136 137 /* 138 * Fix up the FILE fields, and set __cleanup for output flush on 139 * exit (since we are buffered in some way). 140 */ 141 if (mode == _IOLBF) 142 flags |= __SLBF; 143 fp->pub._flags = flags; 144 fp->_bf._base = fp->pub._p = (unsigned char *)buf; 145 fp->_bf._size = size; 146 /* fp->_lbfsize is still 0 */ 147 if (flags & __SWR) { 148 /* 149 * Begin or continue writing: see __swsetup(). Note 150 * that __SNBF is impossible (it was handled earlier). 151 */ 152 if (flags & __SLBF) { 153 fp->pub._w = 0; 154 fp->pub._lbfsize = -fp->_bf._size; 155 } else 156 fp->pub._w = size; 157 } else { 158 /* begin/continue reading, or stay in intermediate state */ 159 fp->pub._w = 0; 160 } 161 __cleanup = _cleanup; 162 163 FUNLOCKFILE(fp); 164 return (ret); 165 } 166