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