1 /* $NetBSD: setvbuf.c,v 1.19 2012/03/15 18:22:30 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[] = "@(#)setvbuf.c 8.2 (Berkeley) 11/16/93"; 39 #else 40 __RCSID("$NetBSD: setvbuf.c,v 1.19 2012/03/15 18:22:30 christos Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <wchar.h> 49 #include "reentrant.h" 50 #include "local.h" 51 52 /* 53 * Set one of the three kinds of buffering, optionally including 54 * a buffer. 55 */ 56 int 57 setvbuf(FILE *fp, char *buf, int mode, size_t size) 58 { 59 int ret, flags; 60 size_t iosize; 61 int ttyflag; 62 63 _DIAGASSERT(fp != NULL); 64 /* buf may be NULL */ 65 66 /* 67 * Verify arguments. The `int' limit on `size' is due to this 68 * particular implementation. Note, buf and size are ignored 69 * when setting _IONBF. 70 */ 71 if (mode != _IONBF) 72 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 73 return -1; 74 75 FLOCKFILE(fp); 76 /* 77 * Write current buffer, if any. Discard unread input (including 78 * ungetc data), cancel line buffering, and free old buffer if 79 * malloc()ed. We also clear any eof condition, as if this were 80 * a seek. 81 */ 82 ret = 0; 83 (void)__sflush(fp); 84 if (HASUB(fp)) 85 FREEUB(fp); 86 WCIO_FREE(fp); 87 fp->_r = fp->_lbfsize = 0; 88 flags = fp->_flags; 89 if (flags & __SMBF) 90 free((void *)fp->_bf._base); 91 flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); 92 93 /* If setting unbuffered mode, skip all the hard work. */ 94 if (mode == _IONBF) 95 goto nbf; 96 97 /* 98 * Find optimal I/O size for seek optimization. This also returns 99 * a `tty flag' to suggest that we check isatty(fd), but we do not 100 * care since our caller told us how to buffer. 101 */ 102 flags |= __swhatbuf(fp, &iosize, &ttyflag); 103 if (size == 0) { 104 buf = NULL; /* force local allocation */ 105 size = iosize; 106 } 107 108 /* Allocate buffer if needed. */ 109 if (buf == NULL) { 110 if ((buf = malloc(size)) == NULL) { 111 /* 112 * Unable to honor user's request. We will return 113 * failure, but try again with file system size. 114 */ 115 ret = -1; 116 if (size != iosize) { 117 size = iosize; 118 buf = malloc(size); 119 } 120 } 121 if (buf == NULL) { 122 /* No luck; switch to unbuffered I/O. */ 123 nbf: 124 fp->_flags = flags | __SNBF; 125 fp->_w = 0; 126 fp->_bf._base = fp->_p = fp->_nbuf; 127 fp->_bf._size = 1; 128 FUNLOCKFILE(fp); 129 return ret; 130 } 131 flags |= __SMBF; 132 } 133 134 /* 135 * Kill any seek optimization if the buffer is not the 136 * right size. 137 * 138 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? 139 */ 140 if (size != iosize) 141 flags |= __SNPT; 142 143 /* 144 * Fix up the FILE fields, and set __cleanup for output flush on 145 * exit (since we are buffered in some way). 146 */ 147 if (mode == _IOLBF) 148 flags |= __SLBF; 149 fp->_flags = flags; 150 fp->_bf._base = fp->_p = (unsigned char *)buf; 151 _DIAGASSERT(__type_fit(int, size)); 152 fp->_bf._size = (int)size; 153 /* fp->_lbfsize is still 0 */ 154 if (flags & __SWR) { 155 /* 156 * Begin or continue writing: see __swsetup(). Note 157 * that __SNBF is impossible (it was handled earlier). 158 */ 159 if (flags & __SLBF) { 160 fp->_w = 0; 161 fp->_lbfsize = -fp->_bf._size; 162 } else { 163 _DIAGASSERT(__type_fit(int, size)); 164 fp->_w = (int)size; 165 } 166 } else { 167 /* begin/continue reading, or stay in intermediate state */ 168 fp->_w = 0; 169 } 170 __cleanup = _cleanup; 171 172 FUNLOCKFILE(fp); 173 return ret; 174 } 175
Indexes created Sat Sep 20 22:09:52 GMT 2025