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