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