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 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93";
37 #endif /* LIBC_SCCS and not lint */
38 #include "namespace.h"
39 #include <errno.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include "un-namespace.h"
43
44 #include "libc_private.h"
45 #include "local.h"
46
47 static int lflush(FILE *);
48
49 static int
lflush(FILE * fp)50 lflush(FILE *fp)
51 {
52 int ret = 0;
53
54 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) {
55 FLOCKFILE_CANCELSAFE(fp);
56 ret = __sflush(fp);
57 FUNLOCKFILE_CANCELSAFE();
58 }
59 return (ret);
60 }
61
62 /*
63 * Refill a stdio buffer.
64 * Return EOF on eof or error, 0 otherwise.
65 */
66 int
__srefill(FILE * fp)67 __srefill(FILE *fp)
68 {
69
70 /* make sure stdio is set up */
71 if (!__sdidinit)
72 __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 fp->_p = fp->_bf._base;
133 fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size);
134 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */
135 if (fp->_r <= 0) {
136 if (fp->_r == 0)
137 fp->_flags |= __SEOF;
138 else {
139 fp->_r = 0;
140 fp->_flags |= __SERR;
141 }
142 return (EOF);
143 }
144 return (0);
145 }
146