152 lines
4.4 KiB
C
152 lines
4.4 KiB
C
/* $OpenBSD: setvbuf.c,v 1.8 2005/08/08 08:05:36 espie 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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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((void *)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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return (ret);
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}
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flags |= __SMBF;
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}
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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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__atexit_register_cleanup(_cleanup);
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return (ret);
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}
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