1 /* $OpenBSD: refill.c,v 1.11 2009/11/09 00:18:27 kurt Exp $ */
2 /*-
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Chris Torek.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <errno.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include "local.h"
38
39 static int
lflush(FILE * fp)40 lflush(FILE *fp)
41 {
42 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
43 return (__sflush_locked(fp)); /* ignored... */
44 return (0);
45 }
46
47 /*
48 * Refill a stdio buffer.
49 * Return EOF on eof or error, 0 otherwise.
50 */
51 int
__srefill(FILE * fp)52 __srefill(FILE *fp)
53 {
54 fp->_r = 0; /* largely a convenience for callers */
55
56 #if !defined(__BIONIC__)
57 /* SysV does not make this test; take it out for compatibility */
58 if (fp->_flags & __SEOF)
59 return (EOF);
60 #endif
61
62 /* if not already reading, have to be reading and writing */
63 if ((fp->_flags & __SRD) == 0) {
64 if ((fp->_flags & __SRW) == 0) {
65 errno = EBADF;
66 fp->_flags |= __SERR;
67 return (EOF);
68 }
69 /* switch to reading */
70 if (fp->_flags & __SWR) {
71 if (__sflush(fp))
72 return (EOF);
73 fp->_flags &= ~__SWR;
74 fp->_w = 0;
75 fp->_lbfsize = 0;
76 }
77 fp->_flags |= __SRD;
78 } else {
79 /*
80 * We were reading. If there is an ungetc buffer,
81 * we must have been reading from that. Drop it,
82 * restoring the previous buffer (if any). If there
83 * is anything in that buffer, return.
84 */
85 if (HASUB(fp)) {
86 FREEUB(fp);
87 if ((fp->_r = fp->_ur) != 0) {
88 fp->_p = fp->_up;
89 return (0);
90 }
91 }
92 }
93
94 if (fp->_bf._base == NULL)
95 __smakebuf(fp);
96
97 /*
98 * Before reading from a line buffered or unbuffered file,
99 * flush all line buffered output files, per the ANSI C
100 * standard.
101 */
102 if (fp->_flags & (__SLBF|__SNBF)) {
103 /* Ignore this file in _fwalk to avoid potential deadlock. */
104 fp->_flags |= __SIGN;
105 (void) _fwalk(lflush);
106 fp->_flags &= ~__SIGN;
107
108 /* Now flush this file without locking it. */
109 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
110 __sflush(fp);
111 }
112 fp->_p = fp->_bf._base;
113 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size);
114 if (fp->_r <= 0) {
115 if (fp->_r == 0)
116 fp->_flags |= __SEOF;
117 else {
118 fp->_r = 0;
119 fp->_flags |= __SERR;
120 }
121 return (EOF);
122 }
123 return (0);
124 }
125