2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)freopen.c 8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
43 #include "namespace.h"
44 #include <sys/types.h>
51 #include "un-namespace.h"
52 #include "libc_private.h"
56 * Re-direct an existing, open (probably) file to some other file.
57 * ANSI is written such that the original file gets closed if at
58 * all possible, no matter what.
61 freopen(file, mode, fp)
62 const char * __restrict file;
63 const char * __restrict mode;
67 int dflags, flags, isopen, oflags, sverrno, wantfd;
69 if ((flags = __sflags(mode, &oflags)) == 0) {
80 * If the filename is a NULL pointer, the caller is asking us to
81 * re-open the same file with a different mode. We allow this only
82 * if the modes are compatible.
85 /* See comment below regarding freopen() of closed files. */
86 if (fp->_flags == 0) {
91 if ((dflags = _fcntl(fp->_file, F_GETFL)) < 0) {
98 if ((dflags & O_ACCMODE) != O_RDWR && (dflags & O_ACCMODE) !=
99 (oflags & O_ACCMODE)) {
105 if ((oflags ^ dflags) & O_APPEND) {
107 dflags |= oflags & O_APPEND;
108 if (_fcntl(fp->_file, F_SETFL, dflags) < 0) {
116 if (oflags & O_TRUNC)
117 ftruncate(fp->_file, 0);
118 if (_fseeko(fp, 0, oflags & O_APPEND ? SEEK_END : SEEK_SET,
119 0) < 0 && errno != ESPIPE) {
133 * There are actually programs that depend on being able to "freopen"
134 * descriptors that weren't originally open. Keep this from breaking.
135 * Remember whether the stream was open to begin with, and which file
136 * descriptor (if any) was associated with it. If it was attached to
137 * a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin)
138 * should work. This is unnecessary if it was not a Unix file.
140 if (fp->_flags == 0) {
141 fp->_flags = __SEOF; /* hold on to it */
145 /* flush the stream; ANSI doesn't require this. */
146 if (fp->_flags & __SWR)
148 /* if close is NULL, closing is a no-op, hence pointless */
149 isopen = fp->_close != NULL;
150 if ((wantfd = fp->_file) < 0 && isopen) {
151 (void) (*fp->_close)(fp->_cookie);
156 /* Get a new descriptor to refer to the new file. */
157 f = _open(file, oflags, DEFFILEMODE);
158 if (f < 0 && isopen) {
159 /* If out of fd's close the old one and try again. */
160 if (errno == ENFILE || errno == EMFILE) {
161 (void) (*fp->_close)(fp->_cookie);
163 f = _open(file, oflags, DEFFILEMODE);
170 * Finish closing fp. Even if the open succeeded above, we cannot
171 * keep fp->_base: it may be the wrong size. This loses the effect
172 * of any setbuffer calls, but stdio has always done this before.
175 (void) (*fp->_close)(fp->_cookie);
176 if (fp->_flags & __SMBF)
177 free((char *)fp->_bf._base);
181 fp->_bf._base = NULL;
190 fp->_extra->orientation = 0;
191 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
193 if (f < 0) { /* did not get it after all */
194 fp->_flags = 0; /* set it free */
195 errno = sverrno; /* restore in case _close clobbered */
201 * If reopening something that was open before on a real file, try
202 * to maintain the descriptor. Various C library routines (perror)
203 * assume stderr is always fd STDERR_FILENO, even if being freopen'd.
205 if (wantfd >= 0 && f != wantfd) {
206 if (_dup2(f, wantfd) >= 0) {
216 fp->_write = __swrite;
218 fp->_close = __sclose;