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 "$Id$"; 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include "local.h" 48 #ifdef _THREAD_SAFE 49 #include <pthread.h> 50 #include "pthread_private.h" 51 #endif 52 53 /* 54 * Set one of the three kinds of buffering, optionally including 55 * a buffer. 56 */ 57 int 58 setvbuf(fp, buf, mode, size) 59 register FILE *fp; 60 char *buf; 61 register int mode; 62 register size_t size; 63 { 64 register int ret, flags; 65 size_t iosize; 66 int ttyflag; 67 68 /* 69 * Verify arguments. The `int' limit on `size' is due to this 70 * particular implementation. Note, buf and size are ignored 71 * when setting _IONBF. 72 */ 73 if (mode != _IONBF) 74 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 75 return (EOF); 76 77 #ifdef _THREAD_SAFE 78 _thread_flockfile(fp,__FILE__,__LINE__); 79 #endif 80 /* 81 * Write current buffer, if any. Discard unread input (including 82 * ungetc data), cancel line buffering, and free old buffer if 83 * malloc()ed. We also clear any eof condition, as if this were 84 * a seek. 85 */ 86 ret = 0; 87 (void)__sflush(fp); 88 if (HASUB(fp)) 89 FREEUB(fp); 90 fp->_r = fp->_lbfsize = 0; 91 flags = fp->_flags; 92 if (flags & __SMBF) 93 free((void *)fp->_bf._base); 94 flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); 95 96 /* If setting unbuffered mode, skip all the hard work. */ 97 if (mode == _IONBF) 98 goto nbf; 99 100 /* 101 * Find optimal I/O size for seek optimization. This also returns 102 * a `tty flag' to suggest that we check isatty(fd), but we do not 103 * care since our caller told us how to buffer. 104 */ 105 flags |= __swhatbuf(fp, &iosize, &ttyflag); 106 if (size == 0) { 107 buf = NULL; /* force local allocation */ 108 size = iosize; 109 } 110 111 /* Allocate buffer if needed. */ 112 if (buf == NULL) { 113 if ((buf = malloc(size)) == NULL) { 114 /* 115 * Unable to honor user's request. We will return 116 * failure, but try again with file system size. 117 */ 118 ret = EOF; 119 if (size != iosize) { 120 size = iosize; 121 buf = malloc(size); 122 } 123 } 124 if (buf == NULL) { 125 /* No luck; switch to unbuffered I/O. */ 126 nbf: 127 fp->_flags = flags | __SNBF; 128 fp->_w = 0; 129 fp->_bf._base = fp->_p = fp->_nbuf; 130 fp->_bf._size = 1; 131 #ifdef _THREAD_SAFE 132 _thread_funlockfile(fp); 133 #endif 134 return (ret); 135 } 136 flags |= __SMBF; 137 } 138 139 /* 140 * Kill any seek optimization if the buffer is not the 141 * right size. 142 * 143 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? 144 */ 145 if (size != iosize) 146 flags |= __SNPT; 147 148 /* 149 * Fix up the FILE fields, and set __cleanup for output flush on 150 * exit (since we are buffered in some way). 151 */ 152 if (mode == _IOLBF) 153 flags |= __SLBF; 154 fp->_flags = flags; 155 fp->_bf._base = fp->_p = (unsigned char *)buf; 156 fp->_bf._size = size; 157 /* fp->_lbfsize is still 0 */ 158 if (flags & __SWR) { 159 /* 160 * Begin or continue writing: see __swsetup(). Note 161 * that __SNBF is impossible (it was handled earlier). 162 */ 163 if (flags & __SLBF) { 164 fp->_w = 0; 165 fp->_lbfsize = -fp->_bf._size; 166 } else 167 fp->_w = size; 168 } else { 169 /* begin/continue reading, or stay in intermediate state */ 170 fp->_w = 0; 171 } 172 __cleanup = _cleanup; 173 174 #ifdef _THREAD_SAFE 175 _thread_funlockfile(fp); 176 #endif 177 return (ret); 178 } 179