[apple/libc.git] / stdio / FreeBSD / freopen.c

/*-
 * 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 1.13 2004/05/22 15:19:41 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;
	memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));

	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);
}
Commit	Line	Data
9385eb3d	1	/*-
e9ce8d39 A	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	* 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.
	23	*
	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
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	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
	34	* SUCH DAMAGE.
	35	*/
	36
9385eb3d A	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>
3d9156a7	41	__FBSDID("$FreeBSD: src/lib/libc/stdio/freopen.c,v 1.13 2004/05/22 15:19:41 tjr Exp $");
e9ce8d39	42
9385eb3d	43	#include "namespace.h"
e9ce8d39 A	44	#include <sys/types.h>
	45	#include <sys/stat.h>
	46	#include <fcntl.h>
	47	#include <errno.h>
	48	#include <unistd.h>
	49	#include <stdio.h>
	50	#include <stdlib.h>
9385eb3d A	51	#include "un-namespace.h"
9385eb3d A	52	#include "libc_private.h"
e9ce8d39 A	53	#include "local.h"
e9ce8d39 A	54
9385eb3d A	55	/*
9385eb3d A	56	* Re-direct an existing, open (probably) file to some other file.
e9ce8d39 A	57	* ANSI is written such that the original file gets closed if at
	58	* all possible, no matter what.
	59	*/
	60	FILE *
	61	freopen(file, mode, fp)
9385eb3d A	62	const char * __restrict file;
	63	const char * __restrict mode;
	64	FILE *fp;
e9ce8d39	65	{
9385eb3d A	66	int f;
9385eb3d A	67	int dflags, flags, isopen, oflags, sverrno, wantfd;
e9ce8d39 A	68
	69	if ((flags = __sflags(mode, &oflags)) == 0) {
	70	(void) fclose(fp);
	71	return (NULL);
	72	}
	73
9385eb3d A	74	FLOCKFILE(fp);
9385eb3d A	75
e9ce8d39 A	76	if (!__sdidinit)
	77	__sinit();
	78
9385eb3d A	79	/*
	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.
	83	*/
	84	if (file == NULL) {
	85	/* See comment below regarding freopen() of closed files. */
	86	if (fp->_flags == 0) {
	87	FUNLOCKFILE(fp);
	88	errno = EINVAL;
	89	return (NULL);
	90	}
	91	if ((dflags = _fcntl(fp->_file, F_GETFL)) < 0) {
	92	sverrno = errno;
	93	fclose(fp);
	94	FUNLOCKFILE(fp);
	95	errno = sverrno;
	96	return (NULL);
	97	}
	98	if ((dflags & O_ACCMODE) != O_RDWR && (dflags & O_ACCMODE) !=
	99	(oflags & O_ACCMODE)) {
	100	fclose(fp);
	101	FUNLOCKFILE(fp);
	102	errno = EINVAL;
	103	return (NULL);
	104	}
	105	if ((oflags ^ dflags) & O_APPEND) {
	106	dflags &= ~O_APPEND;
	107	dflags \|= oflags & O_APPEND;
	108	if (_fcntl(fp->_file, F_SETFL, dflags) < 0) {
	109	sverrno = errno;
	110	fclose(fp);
	111	FUNLOCKFILE(fp);
	112	errno = sverrno;
	113	return (NULL);
	114	}
	115	}
	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) {
	120	sverrno = errno;
	121	fclose(fp);
	122	FUNLOCKFILE(fp);
	123	errno = sverrno;
	124	return (NULL);
	125	}
	126	f = fp->_file;
	127	isopen = 0;
	128	wantfd = -1;
	129	goto finish;
	130	}
	131
e9ce8d39 A	132	/*
	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.
	139	*/
	140	if (fp->_flags == 0) {
	141	fp->_flags = __SEOF; /* hold on to it */
	142	isopen = 0;
	143	wantfd = -1;
	144	} else {
	145	/* flush the stream; ANSI doesn't require this. */
	146	if (fp->_flags & __SWR)
	147	(void) __sflush(fp);
	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);
	152	isopen = 0;
	153	}
	154	}
	155
	156	/* Get a new descriptor to refer to the new file. */
9385eb3d	157	f = _open(file, oflags, DEFFILEMODE);
e9ce8d39 A	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);
	162	isopen = 0;
9385eb3d	163	f = _open(file, oflags, DEFFILEMODE);
e9ce8d39 A	164	}
	165	}
	166	sverrno = errno;
	167
9385eb3d	168	finish:
e9ce8d39 A	169	/*
	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.
	173	*/
	174	if (isopen)
	175	(void) (*fp->_close)(fp->_cookie);
	176	if (fp->_flags & __SMBF)
	177	free((char *)fp->_bf._base);
	178	fp->_w = 0;
	179	fp->_r = 0;
	180	fp->_p = NULL;
	181	fp->_bf._base = NULL;
	182	fp->_bf._size = 0;
	183	fp->_lbfsize = 0;
	184	if (HASUB(fp))
	185	FREEUB(fp);
	186	fp->_ub._size = 0;
	187	if (HASLB(fp))
	188	FREELB(fp);
	189	fp->_lb._size = 0;
9385eb3d	190	fp->_extra->orientation = 0;
3d9156a7	191	memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
e9ce8d39 A	192
	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 */
9385eb3d	196	FUNLOCKFILE(fp);
e9ce8d39 A	197	return (NULL);
	198	}
	199
	200	/*
	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.
	204	*/
	205	if (wantfd >= 0 && f != wantfd) {
9385eb3d A	206	if (_dup2(f, wantfd) >= 0) {
9385eb3d A	207	(void)_close(f);
e9ce8d39 A	208	f = wantfd;
	209	}
	210	}
	211
	212	fp->_flags = flags;
	213	fp->_file = f;
	214	fp->_cookie = fp;
	215	fp->_read = __sread;
	216	fp->_write = __swrite;
	217	fp->_seek = __sseek;
	218	fp->_close = __sclose;
9385eb3d	219	FUNLOCKFILE(fp);
e9ce8d39 A	220	return (fp);
e9ce8d39 A	221	}