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Commit	Line	Data
	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	* 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
	33	#if defined(LIBC_SCCS) && !defined(lint)
	34	static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93";
	35	#endif /* LIBC_SCCS and not lint */
	36	#include <sys/cdefs.h>
	37	__FBSDID("$FreeBSD: src/lib/libc/stdio/refill.c,v 1.20 2008/04/17 22:17:54 jhb Exp $");
	38
	39	#include "namespace.h"
	40	#include <errno.h>
	41	#include <stdio.h>
	42	#include <stdlib.h>
	43	#include "un-namespace.h"
	44
	45	#include "libc_private.h"
	46	#include "local.h"
	47
	48	static int lflush(FILE *);
	49
	50	static int
	51	lflush(FILE *fp)
	52	{
	53	int ret = 0;
	54
	55	if ((fp->_flags & (__SLBF\|__SWR)) == (__SLBF\|__SWR)) {
	56	FLOCKFILE(fp);
	57	ret = __sflush(fp);
	58	FUNLOCKFILE(fp);
	59	}
	60	return (ret);
	61	}
	62
	63	/*
	64	* Refill a stdio buffer.
	65	* Return EOF on eof or error, 0 otherwise.
	66	*/
	67	__private_extern__ int
	68	__srefill0(FILE *fp)
	69	{
	70
	71	/* make sure stdio is set up */
	72	pthread_once(&__sdidinit, __sinit);
	73
	74	ORIENT(fp, -1);
	75
	76	fp->_r = 0; /* largely a convenience for callers */
	77
	78	/* SysV does not make this test; take it out for compatibility */
	79	if (fp->_flags & __SEOF)
	80	return (EOF);
	81
	82	/* if not already reading, have to be reading and writing */
	83	if ((fp->_flags & __SRD) == 0) {
	84	if ((fp->_flags & __SRW) == 0) {
	85	errno = EBADF;
	86	fp->_flags \|= __SERR;
	87	return (EOF);
	88	}
	89	/* switch to reading */
	90	if (fp->_flags & __SWR) {
	91	if (__sflush(fp))
	92	return (EOF);
	93	fp->_flags &= ~__SWR;
	94	fp->_w = 0;
	95	fp->_lbfsize = 0;
	96	}
	97	fp->_flags \|= __SRD;
	98	} else {
	99	/*
	100	* We were reading. If there is an ungetc buffer,
	101	* we must have been reading from that. Drop it,
	102	* restoring the previous buffer (if any). If there
	103	* is anything in that buffer, return.
	104	*/
	105	if (HASUB(fp)) {
	106	FREEUB(fp);
	107	if ((fp->_r = fp->_ur) != 0) {
	108	fp->_p = fp->_up;
	109	return (0);
	110	}
	111	}
	112	}
	113
	114	if (fp->_bf._base == NULL)
	115	__smakebuf(fp);
	116
	117	/*
	118	* Before reading from a line buffered or unbuffered file,
	119	* flush all line buffered output files, per the ANSI C
	120	* standard.
	121	*/
	122	if (fp->_flags & (__SLBF\|__SNBF)) {
	123	/* Ignore this file in _fwalk to avoid potential deadlock. */
	124	fp->_flags \|= __SIGN;
	125	(void) _fwalk(lflush);
	126	fp->_flags &= ~__SIGN;
	127
	128	/* Now flush this file without locking it. */
	129	if ((fp->_flags & (__SLBF\|__SWR)) == (__SLBF\|__SWR))
	130	__sflush(fp);
	131	}
	132	return (1);
	133	}
	134
	135	__private_extern__ int
	136	__srefill1(FILE *fp)
	137	{
	138
	139	fp->_p = fp->_bf._base;
	140	fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size);
	141	fp->_flags &= ~__SMOD; /* buffer contents are again pristine */
	142	if (fp->_r <= 0) {
	143	if (fp->_r == 0)
	144	fp->_flags \|= __SEOF;
	145	else {
	146	fp->_r = 0;
	147	fp->_flags \|= __SERR;
	148	}
	149	return (EOF);
	150	}
	151	return (0);
	152	}
	153
	154	int
	155	__srefill(FILE *fp)
	156	{
	157	int ret;
	158
	159	if ((ret = __srefill0(fp)) <= 0)
	160	return ret;
	161	return __srefill1(fp);
	162	}