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 | * 4. 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 | ␊ |
33 | #if defined(LIBC_SCCS) && !defined(lint)␊ |
34 | static char sccsid[] = "@(#)fflush.c␉8.1 (Berkeley) 6/4/93";␊ |
35 | #endif /* LIBC_SCCS and not lint */␊ |
36 | #include <sys/cdefs.h>␊ |
37 | __FBSDID("$FreeBSD: src/lib/libc/stdio/fflush.c,v 1.14 2007/01/09 00:28:06 imp Exp $");␊ |
38 | ␊ |
39 | #include "namespace.h"␊ |
40 | #include <errno.h>␊ |
41 | #include <stdio.h>␊ |
42 | #include <string.h>␊ |
43 | #include "un-namespace.h"␊ |
44 | #include "local.h"␊ |
45 | ␊ |
46 | static int␉sflush_locked(FILE *);␊ |
47 | ␊ |
48 | ␊ |
49 | /*␊ |
50 | * Flush a single file, or (if fp is NULL) all files.␊ |
51 | */␊ |
52 | int␊ |
53 | fflush(FILE *fp)␊ |
54 | {␊ |
55 | ␉int retval;␊ |
56 | ␊ |
57 | ␉if (fp == NULL)␊ |
58 | ␉␉return (_fwalk(sflush_locked));␊ |
59 | ␊ |
60 | ␉/*␊ |
61 | ␉ * 11103146: Conformance change:␊ |
62 | ␉ * --- Begin History ---␊ |
63 | ␉ * There is disagreement about the correct behaviour of fflush()␊ |
64 | ␉ * when passed a file which is not open for writing. According to␊ |
65 | ␉ * the ISO C standard, the behaviour is undefined.␊ |
66 | ␉ * Under linux, such an fflush returns success and has no effect;␊ |
67 | ␉ * under Windows, such an fflush is documented as behaving instead␊ |
68 | ␉ * as fpurge().␊ |
69 | ␉ * Given that applications may be written with the expectation of␊ |
70 | ␉ * either of these two behaviours, the only safe (non-astonishing)␊ |
71 | ␉ * option is to return EBADF and ask that applications be fixed.␊ |
72 | ␉ * --- End History ---␊ |
73 | ␉ * SUSv3 now requires that fflush() returns success on a read-only␊ |
74 | ␉ * stream. In addition, the conformance tests will warn if a fflush␊ |
75 | ␉ * on a read-only stream does not set the file descriptor's file offset␊ |
76 | ␉ * to the real position. We won't be fixing the warning at this time.␊ |
77 | ␉ */␊ |
78 | ␉if ((fp->_flags & (__SWR | __SRW)) == 0) {␊ |
79 | ␉␉retval = 0;␊ |
80 | ␉} else␊ |
81 | ␉␉retval = __sflush(fp);␊ |
82 | ␉return (retval);␊ |
83 | }␊ |
84 | ␊ |
85 | /*␊ |
86 | * Flush a single file, or (if fp is NULL) all files.␊ |
87 | * Non-MT-safe version␊ |
88 | */␊ |
89 | int␊ |
90 | __fflush(FILE *fp)␊ |
91 | {␊ |
92 | ␉int retval;␊ |
93 | ␊ |
94 | ␉if (fp == NULL)␊ |
95 | ␉␉return (_fwalk(sflush_locked));␊ |
96 | ␉if ((fp->_flags & (__SWR | __SRW)) == 0) {␊ |
97 | ␉␉retval = 0;␊ |
98 | ␉} else␊ |
99 | ␉␉retval = __sflush(fp);␊ |
100 | ␉return (retval);␊ |
101 | }␊ |
102 | ␊ |
103 | int␊ |
104 | __sflush(FILE *fp)␊ |
105 | {␊ |
106 | ␉unsigned char *p;␊ |
107 | ␉int n, t;␊ |
108 | ␊ |
109 | ␉t = fp->_flags;␊ |
110 | ␉if ((t & __SWR) == 0)␊ |
111 | ␉␉return (0);␊ |
112 | ␊ |
113 | ␉if ((p = fp->_bf._base) == NULL)␊ |
114 | ␉␉return (0);␊ |
115 | ␊ |
116 | ␉n = fp->_p - p;␉␉/* write this much */␊ |
117 | ␊ |
118 | ␉/*␊ |
119 | ␉ * Set these immediately to avoid problems with longjmp and to allow␊ |
120 | ␉ * exchange buffering (via setvbuf) in user write function.␊ |
121 | ␉ */␊ |
122 | ␉fp->_p = p;␊ |
123 | ␉fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;␊ |
124 | ␊ |
125 | ␉for (; n > 0; n -= t, p += t) {␊ |
126 | ␉␉t = _swrite(fp, (char *)p, n);␊ |
127 | ␉␉if (t <= 0) {␊ |
128 | ␉␉␉/* 5340694: reset _p and _w on EAGAIN */␊ |
129 | ␉␉␉if (t < 0 && errno == EAGAIN) {␊ |
130 | ␉␉␉␉if (p > fp->_p) /* some was written */␊ |
131 | ␉␉␉␉␉memmove(fp->_p, p, n);␊ |
132 | ␉␉␉␉fp->_p += n;␊ |
133 | ␉␉␉␉if (!(fp->_flags & (__SLBF|__SNBF)))␊ |
134 | ␉␉␉␉␉fp->_w -= n;␊ |
135 | ␉␉␉}␊ |
136 | ␉␉␉fp->_flags |= __SERR;␊ |
137 | ␉␉␉return (EOF);␊ |
138 | ␉␉}␊ |
139 | ␉}␊ |
140 | ␉return (0);␊ |
141 | }␊ |
142 | ␊ |
143 | static int␊ |
144 | sflush_locked(FILE *fp)␊ |
145 | {␊ |
146 | ␉int␉ret;␊ |
147 | ␊ |
148 | ␉ret = __sflush(fp);␊ |
149 | ␉return (ret);␊ |
150 | } |