+/*-
+ * Copyright (c) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)freopen.c 8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: src/lib/libc/stdio/freopen.c,v 1.12 2003/01/26 11:45:54 tjr Exp $");
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "un-namespace.h"
+#include "libc_private.h"
+#include "local.h"
+
+/*
+ * Re-direct an existing, open (probably) file to some other file.
+ * ANSI is written such that the original file gets closed if at
+ * all possible, no matter what.
+ */
+FILE *
+freopen(file, mode, fp)
+ const char * __restrict file;
+ const char * __restrict mode;
+ FILE *fp;
+{
+ int f;
+ int dflags, flags, isopen, oflags, sverrno, wantfd;
+
+ if ((flags = __sflags(mode, &oflags)) == 0) {
+ (void) fclose(fp);
+ return (NULL);
+ }
+
+ FLOCKFILE(fp);
+
+ if (!__sdidinit)
+ __sinit();
+
+ /*
+ * If the filename is a NULL pointer, the caller is asking us to
+ * re-open the same file with a different mode. We allow this only
+ * if the modes are compatible.
+ */
+ if (file == NULL) {
+ /* See comment below regarding freopen() of closed files. */
+ if (fp->_flags == 0) {
+ FUNLOCKFILE(fp);
+ errno = EINVAL;
+ return (NULL);
+ }
+ if ((dflags = _fcntl(fp->_file, F_GETFL)) < 0) {
+ sverrno = errno;
+ fclose(fp);
+ FUNLOCKFILE(fp);
+ errno = sverrno;
+ return (NULL);
+ }
+ if ((dflags & O_ACCMODE) != O_RDWR && (dflags & O_ACCMODE) !=
+ (oflags & O_ACCMODE)) {
+ fclose(fp);
+ FUNLOCKFILE(fp);
+ errno = EINVAL;
+ return (NULL);
+ }
+ if ((oflags ^ dflags) & O_APPEND) {
+ dflags &= ~O_APPEND;
+ dflags |= oflags & O_APPEND;
+ if (_fcntl(fp->_file, F_SETFL, dflags) < 0) {
+ sverrno = errno;
+ fclose(fp);
+ FUNLOCKFILE(fp);
+ errno = sverrno;
+ return (NULL);
+ }
+ }
+ if (oflags & O_TRUNC)
+ ftruncate(fp->_file, 0);
+ if (_fseeko(fp, 0, oflags & O_APPEND ? SEEK_END : SEEK_SET,
+ 0) < 0 && errno != ESPIPE) {
+ sverrno = errno;
+ fclose(fp);
+ FUNLOCKFILE(fp);
+ errno = sverrno;
+ return (NULL);
+ }
+ f = fp->_file;
+ isopen = 0;
+ wantfd = -1;
+ goto finish;
+ }
+
+ /*
+ * There are actually programs that depend on being able to "freopen"
+ * descriptors that weren't originally open. Keep this from breaking.
+ * Remember whether the stream was open to begin with, and which file
+ * descriptor (if any) was associated with it. If it was attached to
+ * a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin)
+ * should work. This is unnecessary if it was not a Unix file.
+ */
+ if (fp->_flags == 0) {
+ fp->_flags = __SEOF; /* hold on to it */
+ isopen = 0;
+ wantfd = -1;
+ } else {
+ /* flush the stream; ANSI doesn't require this. */
+ if (fp->_flags & __SWR)
+ (void) __sflush(fp);
+ /* if close is NULL, closing is a no-op, hence pointless */
+ isopen = fp->_close != NULL;
+ if ((wantfd = fp->_file) < 0 && isopen) {
+ (void) (*fp->_close)(fp->_cookie);
+ isopen = 0;
+ }
+ }
+
+ /* Get a new descriptor to refer to the new file. */
+ f = _open(file, oflags, DEFFILEMODE);
+ if (f < 0 && isopen) {
+ /* If out of fd's close the old one and try again. */
+ if (errno == ENFILE || errno == EMFILE) {
+ (void) (*fp->_close)(fp->_cookie);
+ isopen = 0;
+ f = _open(file, oflags, DEFFILEMODE);
+ }
+ }
+ sverrno = errno;
+
+finish:
+ /*
+ * Finish closing fp. Even if the open succeeded above, we cannot
+ * keep fp->_base: it may be the wrong size. This loses the effect
+ * of any setbuffer calls, but stdio has always done this before.
+ */
+ if (isopen)
+ (void) (*fp->_close)(fp->_cookie);
+ if (fp->_flags & __SMBF)
+ free((char *)fp->_bf._base);
+ fp->_w = 0;
+ fp->_r = 0;
+ fp->_p = NULL;
+ fp->_bf._base = NULL;
+ fp->_bf._size = 0;
+ fp->_lbfsize = 0;
+ if (HASUB(fp))
+ FREEUB(fp);
+ fp->_ub._size = 0;
+ if (HASLB(fp))
+ FREELB(fp);
+ fp->_lb._size = 0;
+ fp->_extra->orientation = 0;
+
+ if (f < 0) { /* did not get it after all */
+ fp->_flags = 0; /* set it free */
+ errno = sverrno; /* restore in case _close clobbered */
+ FUNLOCKFILE(fp);
+ return (NULL);
+ }
+
+ /*
+ * If reopening something that was open before on a real file, try
+ * to maintain the descriptor. Various C library routines (perror)
+ * assume stderr is always fd STDERR_FILENO, even if being freopen'd.
+ */
+ if (wantfd >= 0 && f != wantfd) {
+ if (_dup2(f, wantfd) >= 0) {
+ (void)_close(f);
+ f = wantfd;
+ }
+ }
+
+ fp->_flags = flags;
+ fp->_file = f;
+ fp->_cookie = fp;
+ fp->_read = __sread;
+ fp->_write = __swrite;
+ fp->_seek = __sseek;
+ fp->_close = __sclose;
+ FUNLOCKFILE(fp);
+ return (fp);
+}
projects / apple / libc.git / blobdiff