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Commit	Line	Data
9385eb3d	1	/*-
e9ce8d39 A	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.
e9ce8d39 A	16	* 4. 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
9385eb3d A	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>
1f2f436a	37	__FBSDID("$FreeBSD: src/lib/libc/stdio/setvbuf.c,v 1.14 2007/01/09 00:28:07 imp Exp $");
e9ce8d39	38
9385eb3d	39	#include "namespace.h"
e9ce8d39 A	40	#include <stdio.h>
e9ce8d39 A	41	#include <stdlib.h>
9385eb3d	42	#include "un-namespace.h"
e9ce8d39	43	#include "local.h"
9385eb3d	44	#include "libc_private.h"
e9ce8d39 A	45
	46	/*
	47	* Set one of the three kinds of buffering, optionally including
	48	* a buffer.
	49	*/
	50	int
9385eb3d	51	setvbuf(FILE * __restrict fp, char * __restrict buf, int mode, size_t size)
e9ce8d39	52	{
9385eb3d	53	int ret, flags;
e9ce8d39 A	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
9385eb3d	66	FLOCKFILE(fp);
e9ce8d39 A	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);
9385eb3d	81	flags &= ~(__SLBF \| __SNBF \| __SMBF \| __SOPT \| __SOFF \| __SNPT \| __SEOF);
e9ce8d39 A	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;
9385eb3d	118	FUNLOCKFILE(fp);
e9ce8d39 A	119	return (ret);
	120	}
	121	flags \|= __SMBF;
	122	}
	123
	124	/*
	125	* Kill any seek optimization if the buffer is not the
	126	* right size.
	127	*
	128	* SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?
	129	*/
	130	if (size != iosize)
	131	flags \|= __SNPT;
	132
	133	/*
	134	* Fix up the FILE fields, and set __cleanup for output flush on
	135	* exit (since we are buffered in some way).
	136	*/
	137	if (mode == _IOLBF)
	138	flags \|= __SLBF;
	139	fp->_flags = flags;
	140	fp->_bf._base = fp->_p = (unsigned char *)buf;
	141	fp->_bf._size = size;
	142	/* fp->_lbfsize is still 0 */
	143	if (flags & __SWR) {
	144	/*
	145	* Begin or continue writing: see __swsetup(). Note
	146	* that __SNBF is impossible (it was handled earlier).
	147	*/
	148	if (flags & __SLBF) {
	149	fp->_w = 0;
	150	fp->_lbfsize = -fp->_bf._size;
	151	} else
	152	fp->_w = size;
	153	} else {
	154	/* begin/continue reading, or stay in intermediate state */
	155	fp->_w = 0;
	156	}
	157	__cleanup = _cleanup;
	158
9385eb3d	159	FUNLOCKFILE(fp);
e9ce8d39 A	160	return (ret);
e9ce8d39 A	161	}