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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)setvbuf.c 8.2 (Berkeley) 11/16/93"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "namespace.h" 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include "un-namespace.h" 43 #include "local.h" 44 #include "libc_private.h" 45 46 /* 47 * Set one of the three kinds of buffering, optionally including 48 * a buffer. 49 */ 50 int 51 setvbuf(FILE * __restrict fp, char * __restrict buf, int mode, size_t size) 52 { 53 int ret, flags; 54 size_t iosize; 55 int ttyflag; 56 57 /* 58 * Verify arguments. The `int' limit on `size' is due to this 59 * particular implementation. Note, buf and size are ignored 60 * when setting _IONBF. 61 */ 62 if (mode != _IONBF) 63 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 64 return (EOF); 65 66 FLOCKFILE_CANCELSAFE(fp); 67 /* 68 * Write current buffer, if any. Discard unread input (including 69 * ungetc data), cancel line buffering, and free old buffer if 70 * malloc()ed. We also clear any eof condition, as if this were 71 * a seek. 72 */ 73 ret = 0; 74 (void)__sflush(fp); 75 if (HASUB(fp)) 76 FREEUB(fp); 77 fp->_r = fp->_lbfsize = 0; 78 flags = fp->_flags; 79 if (flags & __SMBF) 80 free((void *)fp->_bf._base); 81 flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SOFF | __SNPT | __SEOF); 82 83 /* If setting unbuffered mode, skip all the hard work. */ 84 if (mode == _IONBF) 85 goto nbf; 86 87 /* 88 * Find optimal I/O size for seek optimization. This also returns 89 * a `tty flag' to suggest that we check isatty(fd), but we do not 90 * care since our caller told us how to buffer. 91 */ 92 flags |= __swhatbuf(fp, &iosize, &ttyflag); 93 if (size == 0) { 94 buf = NULL; /* force local allocation */ 95 size = iosize; 96 } 97 98 /* Allocate buffer if needed. */ 99 if (buf == NULL) { 100 if ((buf = malloc(size)) == NULL) { 101 /* 102 * Unable to honor user's request. We will return 103 * failure, but try again with file system size. 104 */ 105 ret = EOF; 106 if (size != iosize) { 107 size = iosize; 108 buf = malloc(size); 109 } 110 } 111 if (buf == NULL) { 112 /* No luck; switch to unbuffered I/O. */ 113 nbf: 114 fp->_flags = flags | __SNBF; 115 fp->_w = 0; 116 fp->_bf._base = fp->_p = fp->_nbuf; 117 fp->_bf._size = 1; 118 goto end; 119 } 120 flags |= __SMBF; 121 } 122 123 /* 124 * Kill any seek optimization if the buffer is not the 125 * right size. 126 * 127 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? 128 */ 129 if (size != iosize) 130 flags |= __SNPT; 131 132 /* 133 * Fix up the FILE fields, and set __cleanup for output flush on 134 * exit (since we are buffered in some way). 135 */ 136 if (mode == _IOLBF) 137 flags |= __SLBF; 138 fp->_flags = flags; 139 fp->_bf._base = fp->_p = (unsigned char *)buf; 140 fp->_bf._size = size; 141 /* fp->_lbfsize is still 0 */ 142 if (flags & __SWR) { 143 /* 144 * Begin or continue writing: see __swsetup(). Note 145 * that __SNBF is impossible (it was handled earlier). 146 */ 147 if (flags & __SLBF) { 148 fp->_w = 0; 149 fp->_lbfsize = -fp->_bf._size; 150 } else 151 fp->_w = size; 152 } else { 153 /* begin/continue reading, or stay in intermediate state */ 154 fp->_w = 0; 155 } 156 __cleanup = _cleanup; 157 158 end: 159 FUNLOCKFILE_CANCELSAFE(); 160 return (ret); 161 } 162