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 static char sccsid[] = "@(#)setvbuf.c 8.2 (Berkeley) 11/16/93"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include "local.h" 44 #ifdef _THREAD_SAFE 45 #include <pthread.h> 46 #include "pthread_private.h" 47 #endif 48 49 /* 50 * Set one of the three kinds of buffering, optionally including 51 * a buffer. 52 */ 53 int 54 setvbuf(fp, buf, mode, size) 55 register FILE *fp; 56 char *buf; 57 register int mode; 58 register size_t size; 59 { 60 register int ret, flags; 61 size_t iosize; 62 int ttyflag; 63 64 /* 65 * Verify arguments. The `int' limit on `size' is due to this 66 * particular implementation. Note, buf and size are ignored 67 * when setting _IONBF. 68 */ 69 if (mode != _IONBF) 70 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 71 return (EOF); 72 73 #ifdef _THREAD_SAFE 74 _thread_flockfile(fp,__FILE__,__LINE__); 75 #endif 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 fp->_r = fp->_lbfsize = 0; 87 flags = fp->_flags; 88 if (flags & __SMBF) 89 free((void *)fp->_bf._base); 90 flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); 91 92 /* If setting unbuffered mode, skip all the hard work. */ 93 if (mode == _IONBF) 94 goto nbf; 95 96 /* 97 * Find optimal I/O size for seek optimization. This also returns 98 * a `tty flag' to suggest that we check isatty(fd), but we do not 99 * care since our caller told us how to buffer. 100 */ 101 flags |= __swhatbuf(fp, &iosize, &ttyflag); 102 if (size == 0) { 103 buf = NULL; /* force local allocation */ 104 size = iosize; 105 } 106 107 /* Allocate buffer if needed. */ 108 if (buf == NULL) { 109 if ((buf = malloc(size)) == NULL) { 110 /* 111 * Unable to honor user's request. We will return 112 * failure, but try again with file system size. 113 */ 114 ret = EOF; 115 if (size != iosize) { 116 size = iosize; 117 buf = malloc(size); 118 } 119 } 120 if (buf == NULL) { 121 /* No luck; switch to unbuffered I/O. */ 122 nbf: 123 fp->_flags = flags | __SNBF; 124 fp->_w = 0; 125 fp->_bf._base = fp->_p = fp->_nbuf; 126 fp->_bf._size = 1; 127 #ifdef _THREAD_SAFE 128 _thread_funlockfile(fp); 129 #endif 130 return (ret); 131 } 132 flags |= __SMBF; 133 } 134 135 /* 136 * Kill any seek optimization if the buffer is not the 137 * right size. 138 * 139 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? 140 */ 141 if (size != iosize) 142 flags |= __SNPT; 143 144 /* 145 * Fix up the FILE fields, and set __cleanup for output flush on 146 * exit (since we are buffered in some way). 147 */ 148 if (mode == _IOLBF) 149 flags |= __SLBF; 150 fp->_flags = flags; 151 fp->_bf._base = fp->_p = (unsigned char *)buf; 152 fp->_bf._size = 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 fp->_w = size; 164 } else { 165 /* begin/continue reading, or stay in intermediate state */ 166 fp->_w = 0; 167 } 168 __cleanup = _cleanup; 169 170 #ifdef _THREAD_SAFE 171 _thread_funlockfile(fp); 172 #endif 173 return (ret); 174 } 175