1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include "namespace.h"
36 #include <errno.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include "un-namespace.h"
40
41 #include "libc_private.h"
42 #include "local.h"
43
44 static int lflush(FILE *);
45
46 static int
lflush(FILE * fp)47 lflush(FILE *fp)
48 {
49 int ret = 0;
50
51 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) {
52 FLOCKFILE_CANCELSAFE(fp);
53 ret = __sflush(fp);
54 FUNLOCKFILE_CANCELSAFE();
55 }
56 return (ret);
57 }
58
59 /*
60 * Refill a stdio buffer.
61 * Return EOF on eof or error, 0 otherwise.
62 */
63 int
__srefill(FILE * fp)64 __srefill(FILE *fp)
65 {
66
67 /* make sure stdio is set up */
68 if (!__sdidinit)
69 __sinit();
70
71 ORIENT(fp, -1);
72
73 fp->_r = 0; /* largely a convenience for callers */
74
75 /* SysV does not make this test; take it out for compatibility */
76 if (fp->_flags & __SEOF)
77 return (EOF);
78
79 /* if not already reading, have to be reading and writing */
80 if ((fp->_flags & __SRD) == 0) {
81 if ((fp->_flags & __SRW) == 0) {
82 errno = EBADF;
83 fp->_flags |= __SERR;
84 return (EOF);
85 }
86 /* switch to reading */
87 if (fp->_flags & __SWR) {
88 if (__sflush(fp))
89 return (EOF);
90 fp->_flags &= ~__SWR;
91 fp->_w = 0;
92 fp->_lbfsize = 0;
93 }
94 fp->_flags |= __SRD;
95 } else {
96 /*
97 * We were reading. If there is an ungetc buffer,
98 * we must have been reading from that. Drop it,
99 * restoring the previous buffer (if any). If there
100 * is anything in that buffer, return.
101 */
102 if (HASUB(fp)) {
103 FREEUB(fp);
104 if ((fp->_r = fp->_ur) != 0) {
105 fp->_p = fp->_up;
106 return (0);
107 }
108 }
109 }
110
111 if (fp->_bf._base == NULL)
112 __smakebuf(fp);
113
114 /*
115 * Before reading from a line buffered or unbuffered file,
116 * flush all line buffered output files, per the ANSI C
117 * standard.
118 */
119 if (fp->_flags & (__SLBF|__SNBF)) {
120 /* Ignore this file in _fwalk to avoid potential deadlock. */
121 fp->_flags |= __SIGN;
122 (void) _fwalk(lflush);
123 fp->_flags &= ~__SIGN;
124
125 /* Now flush this file without locking it. */
126 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
127 __sflush(fp);
128 }
129 fp->_p = fp->_bf._base;
130 fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size);
131 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */
132 if (fp->_r <= 0) {
133 if (fp->_r == 0)
134 fp->_flags |= __SEOF;
135 else {
136 fp->_r = 0;
137 fp->_flags |= __SERR;
138 }
139 return (EOF);
140 }
141 return (0);
142 }
143