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 "namespace.h" 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include "un-namespace.h" 49 #include "local.h" 50 #include "libc_private.h" 51 52 /* 53 * Set one of the three kinds of buffering, optionally including 54 * a buffer. 55 */ 56 int 57 setvbuf(fp, buf, mode, size) 58 register FILE *fp; 59 char *buf; 60 register int mode; 61 register size_t size; 62 { 63 register int ret, flags; 64 size_t iosize; 65 int ttyflag; 66 67 /* 68 * Verify arguments. The `int' limit on `size' is due to this 69 * particular implementation. Note, buf and size are ignored 70 * when setting _IONBF. 71 */ 72 if (mode != _IONBF) 73 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 74 return (EOF); 75 76 FLOCKFILE(fp); 77 /* 78 * Write current buffer, if any. Discard unread input (including 79 * ungetc data), cancel line buffering, and free old buffer if 80 * malloc()ed. We also clear any eof condition, as if this were 81 * a seek. 82 */ 83 ret = 0; 84 (void)__sflush(fp); 85 if (HASUB(fp)) 86 FREEUB(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 | __SOFF | __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 = EOF; 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 fp->_bf._size = size; 152 /* fp->_lbfsize is still 0 */ 153 if (flags & __SWR) { 154 /* 155 * Begin or continue writing: see __swsetup(). Note 156 * that __SNBF is impossible (it was handled earlier). 157 */ 158 if (flags & __SLBF) { 159 fp->_w = 0; 160 fp->_lbfsize = -fp->_bf._size; 161 } else 162 fp->_w = size; 163 } else { 164 /* begin/continue reading, or stay in intermediate state */ 165 fp->_w = 0; 166 } 167 __cleanup = _cleanup; 168 169 FUNLOCKFILE(fp); 170 return (ret); 171 } 172