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/* $OpenBSD: setvbuf.c,v 1.14 2016/09/21 04:38:56 guenther Exp $ */ |
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/*- |
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* Copyright (c) 1990, 1993 |
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* The Regents of the University of California. All rights reserved. |
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* |
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* This code is derived from software contributed to Berkeley by |
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* Chris Torek. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include "local.h" |
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/* |
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* Set one of the three kinds of buffering, optionally including |
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* a buffer. |
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*/ |
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int |
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setvbuf(FILE *fp, char *buf, int mode, size_t size) |
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{ |
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int ret, flags; |
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size_t iosize; |
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int ttyflag; |
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/* |
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* Verify arguments. The `int' limit on `size' is due to this |
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* particular implementation. Note, buf and size are ignored |
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* when setting _IONBF. |
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*/ |
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if (mode != _IONBF) |
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if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) |
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return (EOF); |
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/* |
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* Write current buffer, if any. Discard unread input (including |
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* ungetc data), cancel line buffering, and free old buffer if |
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* malloc()ed. We also clear any eof condition, as if this were |
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* a seek. |
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*/ |
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FLOCKFILE(fp); |
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ret = 0; |
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(void)__sflush(fp); |
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if (HASUB(fp)) |
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FREEUB(fp); |
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WCIO_FREE(fp); |
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fp->_r = fp->_lbfsize = 0; |
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flags = fp->_flags; |
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if (flags & __SMBF) |
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free(fp->_bf._base); |
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flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); |
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/* If setting unbuffered mode, skip all the hard work. */ |
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if (mode == _IONBF) |
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goto nbf; |
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/* |
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* Find optimal I/O size for seek optimization. This also returns |
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* a `tty flag' to suggest that we check isatty(fd), but we do not |
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* care since our caller told us how to buffer. |
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*/ |
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flags |= __swhatbuf(fp, &iosize, &ttyflag); |
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if (size == 0) { |
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buf = NULL; /* force local allocation */ |
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size = iosize; |
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} |
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/* Allocate buffer if needed. */ |
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if (buf == NULL) { |
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if ((buf = malloc(size)) == NULL) { |
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/* |
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* Unable to honor user's request. We will return |
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* failure, but try again with file system size. |
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*/ |
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ret = EOF; |
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if (size != iosize) { |
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size = iosize; |
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buf = malloc(size); |
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} |
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} |
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if (buf == NULL) { |
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/* No luck; switch to unbuffered I/O. */ |
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nbf: |
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fp->_flags = flags | __SNBF; |
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fp->_w = 0; |
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fp->_bf._base = fp->_p = fp->_nbuf; |
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fp->_bf._size = 1; |
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FUNLOCKFILE(fp); |
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return (ret); |
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} |
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flags |= __SMBF; |
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} |
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/* |
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* We're committed to buffering from here, so make sure we've |
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* registered to flush buffers on exit. |
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*/ |
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if (!__sdidinit) |
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__sinit(); |
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/* |
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* Kill any seek optimization if the buffer is not the |
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* right size. |
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* |
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* SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? |
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*/ |
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if (size != iosize) |
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flags |= __SNPT; |
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/* |
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* Fix up the FILE fields, and set __cleanup for output flush on |
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* exit (since we are buffered in some way). |
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*/ |
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if (mode == _IOLBF) |
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flags |= __SLBF; |
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fp->_flags = flags; |
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fp->_bf._base = fp->_p = (unsigned char *)buf; |
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fp->_bf._size = size; |
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/* fp->_lbfsize is still 0 */ |
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if (flags & __SWR) { |
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/* |
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* Begin or continue writing: see __swsetup(). Note |
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* that __SNBF is impossible (it was handled earlier). |
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*/ |
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if (flags & __SLBF) { |
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fp->_w = 0; |
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fp->_lbfsize = -fp->_bf._size; |
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} else |
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fp->_w = size; |
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} else { |
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/* begin/continue reading, or stay in intermediate state */ |
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fp->_w = 0; |
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} |
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FUNLOCKFILE(fp); |
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return (ret); |
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} |
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DEF_STRONG(setvbuf); |