[apple/libc.git] / gen / FreeBSD / opendir.c

/*-
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 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[] = "@(#)opendir.c	8.8 (Berkeley) 5/1/95";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "namespace.h"
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysctl.h>

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include "un-namespace.h"

#include "telldir.h"

static bool
__kernel_supports_unionfs(void)
{
	static int8_t kernel_supports_unionfs = -1;
	if (kernel_supports_unionfs == -1) {
		int value = 0;
		size_t len = sizeof(value);
		sysctlbyname("kern.secure_kernel", &value, &len, NULL, 0);
		kernel_supports_unionfs = !value;
	}
	return kernel_supports_unionfs;
}

static int
__fd_is_on_union_mount(int fd)
{
	struct statfs stbuf;
	int rc;

	rc = fstatfs(fd, &stbuf);
	if (rc < 0) {
		return rc;
	}
	return (stbuf.f_flags & MNT_UNION) != 0;
}

static DIR * __opendir_common(int, int, bool);

/*
 * Open a directory.
 */
DIR *
opendir(const char *name)
{

	return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
}

/*
 * Open a directory with existing file descriptor.
 */
DIR *
fdopendir(int fd)
{
	struct stat statb;

	/* Check that fd is associated with a directory. */
	if (_fstat(fd, &statb) != 0)
		return (NULL);
	if (!S_ISDIR(statb.st_mode)) {
		errno = ENOTDIR;
		return (NULL);
	}
	/* Make sure CLOEXEC is set on the fd */
	if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
		return (NULL);
	return (__opendir_common(fd, DTF_HIDEW|DTF_NODUP, true));
}

DIR *
__opendir2(const char *name, int flags)
{
	int fd;
	DIR *dir;
	int saved_errno;

	if ((flags & (__DTF_READALL | __DTF_SKIPREAD)) != 0)
		return (NULL);
	if ((fd = _open(name,
	    O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC)) == -1)
		return (NULL);

	dir = __opendir_common(fd, flags, false);
	if (dir == NULL) {
		saved_errno = errno;
		_close(fd);
		errno = saved_errno;
	}
	return (dir);
}

static int
opendir_compar(const void *p1, const void *p2)
{

	return (strcmp((*(const struct dirent **)p1)->d_name,
	    (*(const struct dirent **)p2)->d_name));
}

/*
 * For a directory at the top of a unionfs stack, the entire directory's
 * contents are read and cached locally until the next call to rewinddir().
 * For the fdopendir() case, the initial seek position must be preserved.
 * For rewinddir(), the full directory should always be re-read from the
 * beginning.
 *
 * If an error occurs, the existing buffer and state of 'dirp' is left
 * unchanged.
 */
bool
_filldir(DIR *dirp, bool use_current_pos)
{
	struct dirent **dpv;
	char *buf, *ddptr, *ddeptr;
	off_t pos;
	int fd2, incr, len, n, saved_errno, space;
	
	len = 0;
	space = 0;
	buf = NULL;
	ddptr = NULL;

	/*
	 * Use the system page size if that is a multiple of DIRBLKSIZ.
	 * Hopefully this can be a big win someday by allowing page
	 * trades to user space to be done by _getdirentries().
	 */
	incr = getpagesize();
	if ((incr % DIRBLKSIZ) != 0) 
		incr = DIRBLKSIZ;

	/*
	 * The strategy here is to read all the directory
	 * entries into a buffer, sort the buffer, and
	 * remove duplicate entries by setting the inode
	 * number to zero.
	 *
	 * We reopen the directory because _getdirentries()
	 * on a MNT_UNION mount modifies the open directory,
	 * making it refer to the lower directory after the
	 * upper directory's entries are exhausted.
	 * This would otherwise break software that uses
	 * the directory descriptor for fchdir or *at
	 * functions, such as fts.c.
	 */
	if ((fd2 = openat(dirp->dd_fd, ".", O_RDONLY | O_CLOEXEC)) == -1)
		return (false);

	if (use_current_pos) {
		pos = lseek(dirp->dd_fd, 0, SEEK_CUR);
		if (pos == -1 || lseek(fd2, pos, SEEK_SET) == -1) {
			saved_errno = errno;
			_close(fd2);
			errno = saved_errno;
			return (false);
		}
	}

	do {
		/*
		 * Always make at least DIRBLKSIZ bytes
		 * available to _getdirentries
		 */
		if (space < DIRBLKSIZ) {
			space += incr;
			len += incr;
			buf = reallocf(buf, len);
			if (buf == NULL) {
				saved_errno = errno;
				_close(fd2);
				errno = saved_errno;
				return (false);
			}
			ddptr = buf + (len - space);
		}

#if __DARWIN_64_BIT_INO_T
		n = (int)__getdirentries64(fd2, ddptr, space, &dirp->dd_td->seekoff);
#else /* !__DARWIN_64_BIT_INO_T */
		n = _getdirentries(fd2, ddptr, space, &dirp->dd_seek);
#endif /* __DARWIN_64_BIT_INO_T */
		if (n > 0) {
			ddptr += n;
			space -= n;
		}
		if (n < 0) {
			saved_errno = errno;
			_close(fd2);
			errno = saved_errno;
			return (false);
		}
	} while (n > 0);
	_close(fd2);

	ddeptr = ddptr;

	/*
	 * There is now a buffer full of (possibly) duplicate
	 * names.
	 */
	dirp->dd_buf = buf;

	/*
	 * Go round this loop twice...
	 *
	 * Scan through the buffer, counting entries.
	 * On the second pass, save pointers to each one.
	 * Then sort the pointers and remove duplicate names.
	 */
	for (dpv = NULL;;) {
		n = 0;
		ddptr = buf;
		while (ddptr < ddeptr) {
			struct dirent *dp;

			dp = (struct dirent *) ddptr;
			if ((long)dp & 03L)
				break;
			if ((dp->d_reclen <= 0) ||
			    (dp->d_reclen > (ddeptr + 1 - ddptr)))
				break;
			ddptr += dp->d_reclen;
			if (dp->d_fileno) {
				if (dpv)
					dpv[n] = dp;
				n++;
			}
		}

		if (dpv) {
			struct dirent *xp;

			/*
			 * This sort must be stable.
			 */
			mergesort(dpv, n, sizeof(*dpv), opendir_compar);

			dpv[n] = NULL;
			xp = NULL;

			/*
			 * Scan through the buffer in sort order,
			 * zapping the inode number of any
			 * duplicate names.
			 */
			for (n = 0; dpv[n]; n++) {
				struct dirent *dp = dpv[n];

				if ((xp == NULL) ||
				    strcmp(dp->d_name, xp->d_name)) {
					xp = dp;
				} else {
					dp->d_fileno = 0;
				}
				if (dp->d_type == DT_WHT &&
				    (dirp->dd_flags & DTF_HIDEW))
					dp->d_fileno = 0;
			}

			free(dpv);
			break;
		} else {
			dpv = malloc((n+1) * sizeof(struct dirent *));
			if (dpv == NULL)
				break;
		}
	}

	dirp->dd_len = len;
	dirp->dd_size = ddptr - dirp->dd_buf;
	return (true);
}


/*
 * Common routine for opendir(3), __opendir2(3) and fdopendir(3).
 */
static DIR *
__opendir_common(int fd, int flags, bool use_current_pos)
{
	DIR *dirp;
	int saved_errno;
	int unionstack;

	if ((dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL)
		return (NULL);

	dirp->dd_buf = NULL;
	dirp->dd_fd = fd;
	dirp->dd_flags = flags;
	dirp->dd_loc = 0;
	dirp->dd_lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
	dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR));
	LIST_INIT(&dirp->dd_td->td_locq);
	dirp->dd_td->td_loccnt = 0;

	/*
	 * Determine whether this directory is the top of a union stack.
	 */
	if ((flags & DTF_NODUP) && __kernel_supports_unionfs()) {
		unionstack = __fd_is_on_union_mount(fd);
		if (unionstack < 0)
			goto fail;
	} else {
		unionstack = 0;
	}

	if (unionstack) {
		if (!_filldir(dirp, use_current_pos))
			goto fail;
		dirp->dd_flags |= __DTF_READALL;
	} else {
		/*
		 * Start with a small-ish size to avoid allocating full pages.
		 * readdir() will allocate a larger buffer if it didn't fit
		 * to stay fast for large directories.
		 */
		_Static_assert(GETDIRENTRIES64_EXTENDED_BUFSIZE <= READDIR_INITIAL_SIZE,
		    "Make sure we'll get extended metadata");
		dirp->dd_len = READDIR_INITIAL_SIZE;
		dirp->dd_buf = malloc(dirp->dd_len);
		if (dirp->dd_buf == NULL)
			goto fail;
		if (use_current_pos) {
			/*
			 * Read the first batch of directory entries
			 * to prime dd_seek.  This also checks if the
			 * fd passed to fdopendir() is a directory.
			 */
#if __DARWIN_64_BIT_INO_T
			/*
			 * sufficiently recent kernels when the buffer is large enough,
			 * will use the last bytes of the buffer to return status.
			 *
			 * To support older kernels:
			 * - make sure it's 0 initialized
			 * - make sure it's past `dd_size` before reading it
			 */
			getdirentries64_flags_t *gdeflags =
			    (getdirentries64_flags_t *)(dirp->dd_buf + dirp->dd_len -
			    sizeof(getdirentries64_flags_t));
			*gdeflags = 0;
			dirp->dd_size = (long)__getdirentries64(dirp->dd_fd,
			    dirp->dd_buf, dirp->dd_len, &dirp->dd_td->seekoff);
			if (dirp->dd_size >= 0 &&
			    dirp->dd_size <= dirp->dd_len - sizeof(getdirentries64_flags_t)) {
				if (*gdeflags & GETDIRENTRIES64_EOF) {
					dirp->dd_flags |= __DTF_ATEND;
				}
			}
#else /* !__DARWIN_64_BIT_INO_T */
			dirp->dd_size = _getdirentries(dirp->dd_fd,
			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
#endif /* __DARWIN_64_BIT_INO_T */
			if (dirp->dd_size < 0) {
				if (errno == EINVAL)
					errno = ENOTDIR;
				goto fail;
			}
			dirp->dd_flags |= __DTF_SKIPREAD;
		} else {
			dirp->dd_size = 0;
#if __DARWIN_64_BIT_INO_T
			dirp->dd_td->seekoff = 0;
#else /* !__DARWIN_64_BIT_INO_T */
			dirp->dd_seek = 0;
#endif /* __DARWIN_64_BIT_INO_T */
		}
	}

	return (dirp);

fail:
	saved_errno = errno;
	free(dirp->dd_buf);
	free(dirp);
	errno = saved_errno;
	return (NULL);
}
Commit	Line	Data
1f2f436a	1	/*-
e9ce8d39 A	2	* Copyright (c) 1983, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
e9ce8d39 A	13	* 4. Neither the name of the University nor the names of its contributors
	14	* may be used to endorse or promote products derived from this software
	15	* without specific prior written permission.
	16	*
	17	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	20	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	21	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	27	* SUCH DAMAGE.
	28	*/
	29
9385eb3d A	30	#if defined(LIBC_SCCS) && !defined(lint)
	31	static char sccsid[] = "@(#)opendir.c 8.8 (Berkeley) 5/1/95";
	32	#endif /* LIBC_SCCS and not lint */
	33	#include <sys/cdefs.h>
23e20b00	34	__FBSDID("$FreeBSD$");
e9ce8d39	35
9385eb3d	36	#include "namespace.h"
e9ce8d39 A	37	#include <sys/param.h>
	38	#include <sys/mount.h>
	39	#include <sys/stat.h>
507116e3	40	#include <sys/sysctl.h>
e9ce8d39 A	41
	42	#include <dirent.h>
	43	#include <errno.h>
	44	#include <fcntl.h>
	45	#include <stdlib.h>
e9ce8d39	46	#include <string.h>
9385eb3d	47	#include <unistd.h>
ad3c9f2a	48	#include <pthread.h>
9385eb3d A	49	#include "un-namespace.h"
	50
	51	#include "telldir.h"
23e20b00	52
507116e3 A	53	static bool
	54	__kernel_supports_unionfs(void)
	55	{
	56	static int8_t kernel_supports_unionfs = -1;
	57	if (kernel_supports_unionfs == -1) {
	58	int value = 0;
	59	size_t len = sizeof(value);
	60	sysctlbyname("kern.secure_kernel", &value, &len, NULL, 0);
	61	kernel_supports_unionfs = !value;
	62	}
	63	return kernel_supports_unionfs;
	64	}
	65
	66	static int
	67	__fd_is_on_union_mount(int fd)
	68	{
	69	struct statfs stbuf;
	70	int rc;
	71
	72	rc = fstatfs(fd, &stbuf);
	73	if (rc < 0) {
	74	return rc;
	75	}
	76	return (stbuf.f_flags & MNT_UNION) != 0;
	77	}
	78
b061a43b	79	static DIR * __opendir_common(int, int, bool);
23e20b00	80
9385eb3d A	81	/*
	82	* Open a directory.
	83	*/
	84	DIR *
1f2f436a	85	opendir(const char *name)
9385eb3d A	86	{
	87
	88	return (__opendir2(name, DTF_HIDEW\|DTF_NODUP));
	89	}
e9ce8d39	90
23e20b00 A	91	/*
	92	* Open a directory with existing file descriptor.
	93	*/
	94	DIR *
	95	fdopendir(int fd)
	96	{
	97	struct stat statb;
	98
	99	/* Check that fd is associated with a directory. */
	100	if (_fstat(fd, &statb) != 0)
	101	return (NULL);
	102	if (!S_ISDIR(statb.st_mode)) {
	103	errno = ENOTDIR;
	104	return (NULL);
	105	}
b061a43b	106	/* Make sure CLOEXEC is set on the fd */
23e20b00 A	107	if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
23e20b00 A	108	return (NULL);
b061a43b	109	return (__opendir_common(fd, DTF_HIDEW\|DTF_NODUP, true));
23e20b00 A	110	}
23e20b00 A	111
9385eb3d	112	DIR *
1f2f436a	113	__opendir2(const char *name, int flags)
e9ce8d39	114	{
e9ce8d39	115	int fd;
b061a43b A	116	DIR *dir;
b061a43b A	117	int saved_errno;
23e20b00	118
b061a43b A	119	if ((flags & (__DTF_READALL \| __DTF_SKIPREAD)) != 0)
b061a43b A	120	return (NULL);
23e20b00 A	121	if ((fd = _open(name,
	122	O_RDONLY \| O_NONBLOCK \| O_DIRECTORY \| O_CLOEXEC)) == -1)
	123	return (NULL);
	124
b061a43b A	125	dir = __opendir_common(fd, flags, false);
	126	if (dir == NULL) {
	127	saved_errno = errno;
	128	_close(fd);
	129	errno = saved_errno;
	130	}
	131	return (dir);
23e20b00 A	132	}
	133
	134	static int
	135	opendir_compar(const void p1, const void p2)
	136	{
	137
	138	return (strcmp(((const struct dirent *)p1)->d_name,
	139	((const struct dirent *)p2)->d_name));
	140	}
	141
b061a43b A	142	/*
	143	* For a directory at the top of a unionfs stack, the entire directory's
	144	* contents are read and cached locally until the next call to rewinddir().
	145	* For the fdopendir() case, the initial seek position must be preserved.
	146	* For rewinddir(), the full directory should always be re-read from the
	147	* beginning.
	148	*
	149	* If an error occurs, the existing buffer and state of 'dirp' is left
	150	* unchanged.
	151	*/
	152	bool
	153	_filldir(DIR *dirp, bool use_current_pos)
	154	{
	155	struct dirent **dpv;
	156	char buf, ddptr, *ddeptr;
	157	off_t pos;
	158	int fd2, incr, len, n, saved_errno, space;
	159
	160	len = 0;
	161	space = 0;
	162	buf = NULL;
	163	ddptr = NULL;
	164
	165	/*
	166	* Use the system page size if that is a multiple of DIRBLKSIZ.
	167	* Hopefully this can be a big win someday by allowing page
	168	* trades to user space to be done by _getdirentries().
	169	*/
	170	incr = getpagesize();
	171	if ((incr % DIRBLKSIZ) != 0)
	172	incr = DIRBLKSIZ;
	173
	174	/*
	175	* The strategy here is to read all the directory
	176	* entries into a buffer, sort the buffer, and
	177	* remove duplicate entries by setting the inode
	178	* number to zero.
	179	*
	180	* We reopen the directory because _getdirentries()
	181	* on a MNT_UNION mount modifies the open directory,
	182	* making it refer to the lower directory after the
	183	* upper directory's entries are exhausted.
	184	* This would otherwise break software that uses
	185	* the directory descriptor for fchdir or *at
	186	* functions, such as fts.c.
	187	*/
	188	if ((fd2 = openat(dirp->dd_fd, ".", O_RDONLY \| O_CLOEXEC)) == -1)
	189	return (false);
	190
	191	if (use_current_pos) {
	192	pos = lseek(dirp->dd_fd, 0, SEEK_CUR);
	193	if (pos == -1 \|\| lseek(fd2, pos, SEEK_SET) == -1) {
	194	saved_errno = errno;
	195	_close(fd2);
	196	errno = saved_errno;
	197	return (false);
	198	}
	199	}
	200
	201	do {
	202	/*
	203	* Always make at least DIRBLKSIZ bytes
	204	* available to _getdirentries
	205	*/
206	if (space < DIRBLKSIZ) {
207	space += incr;
208	len += incr;
209	buf = reallocf(buf, len);
210	if (buf == NULL) {
211	saved_errno = errno;
212	_close(fd2);
213	errno = saved_errno;
214	return (false);
215	}
216	ddptr = buf + (len - space);
217	}
218
219	#if __DARWIN_64_BIT_INO_T
220	n = (int)__getdirentries64(fd2, ddptr, space, &dirp->dd_td->seekoff);
221	#else /* !__DARWIN_64_BIT_INO_T */
222	n = _getdirentries(fd2, ddptr, space, &dirp->dd_seek);
223	#endif /* __DARWIN_64_BIT_INO_T */
224	if (n > 0) {
225	ddptr += n;
226	space -= n;
227	}
228	if (n < 0) {
229	saved_errno = errno;
230	_close(fd2);
231	errno = saved_errno;
232	return (false);
233	}
234	} while (n > 0);
235	_close(fd2);
236
237	ddeptr = ddptr;
238
239	/*
240	* There is now a buffer full of (possibly) duplicate
241	* names.
242	*/
243	dirp->dd_buf = buf;
244
245	/*
246	* Go round this loop twice...
247	*
248	* Scan through the buffer, counting entries.
249	* On the second pass, save pointers to each one.
250	* Then sort the pointers and remove duplicate names.
251	*/
252	for (dpv = NULL;;) {
253	n = 0;
254	ddptr = buf;
255	while (ddptr < ddeptr) {
256	struct dirent *dp;
257
258	dp = (struct dirent *) ddptr;
259	if ((long)dp & 03L)
260	break;
261	if ((dp->d_reclen <= 0) \|\|
262	(dp->d_reclen > (ddeptr + 1 - ddptr)))
263	break;
264	ddptr += dp->d_reclen;
265	if (dp->d_fileno) {
266	if (dpv)
267	dpv[n] = dp;
268	n++;
269	}
270	}
271
272	if (dpv) {
273	struct dirent *xp;
274
275	/*
276	* This sort must be stable.
277	*/
278	mergesort(dpv, n, sizeof(*dpv), opendir_compar);
279
280	dpv[n] = NULL;
281	xp = NULL;
282
283	/*
284	* Scan through the buffer in sort order,
285	* zapping the inode number of any
286	* duplicate names.
287	*/
288	for (n = 0; dpv[n]; n++) {
289	struct dirent *dp = dpv[n];
290
291	if ((xp == NULL) \|\|
292	strcmp(dp->d_name, xp->d_name)) {
293	xp = dp;
294	} else {
295	dp->d_fileno = 0;
296	}
297	if (dp->d_type == DT_WHT &&
298	(dirp->dd_flags & DTF_HIDEW))
299	dp->d_fileno = 0;
300	}
301
302	free(dpv);
303	break;
304	} else {
305	dpv = malloc((n+1) * sizeof(struct dirent *));
306	if (dpv == NULL)
307	break;
308	}
309	}
310
311	dirp->dd_len = len;
312	dirp->dd_size = ddptr - dirp->dd_buf;
313	return (true);
314	}
315
316
23e20b00 A	317	/*
	318	* Common routine for opendir(3), __opendir2(3) and fdopendir(3).
	319	*/
	320	static DIR *
b061a43b	321	__opendir_common(int fd, int flags, bool use_current_pos)
23e20b00 A	322	{
23e20b00 A	323	DIR *dirp;
9385eb3d	324	int saved_errno;
e9ce8d39	325	int unionstack;
e9ce8d39	326
23e20b00	327	if ((dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL)
e9ce8d39	328	return (NULL);
9385eb3d	329
b061a43b A	330	dirp->dd_buf = NULL;
	331	dirp->dd_fd = fd;
	332	dirp->dd_flags = flags;
	333	dirp->dd_loc = 0;
	334	dirp->dd_lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
3d9156a7	335	dirp->dd_td = (struct _telldir )((char )dirp + sizeof(DIR));
9385eb3d A	336	LIST_INIT(&dirp->dd_td->td_locq);
9385eb3d A	337	dirp->dd_td->td_loccnt = 0;
e9ce8d39	338
e9ce8d39 A	339	/*
	340	* Determine whether this directory is the top of a union stack.
	341	*/
507116e3 A	342	if ((flags & DTF_NODUP) && __kernel_supports_unionfs()) {
	343	unionstack = __fd_is_on_union_mount(fd);
	344	if (unionstack < 0)
9385eb3d	345	goto fail;
e9ce8d39 A	346	} else {
	347	unionstack = 0;
	348	}
	349
	350	if (unionstack) {
b061a43b A	351	if (!_filldir(dirp, use_current_pos))
	352	goto fail;
	353	dirp->dd_flags \|= __DTF_READALL;
	354	} else {
507116e3 A	355	/*
	356	* Start with a small-ish size to avoid allocating full pages.
	357	* readdir() will allocate a larger buffer if it didn't fit
	358	* to stay fast for large directories.
	359	*/
	360	_Static_assert(GETDIRENTRIES64_EXTENDED_BUFSIZE <= READDIR_INITIAL_SIZE,
	361	"Make sure we'll get extended metadata");
	362	dirp->dd_len = READDIR_INITIAL_SIZE;
b061a43b A	363	dirp->dd_buf = malloc(dirp->dd_len);
	364	if (dirp->dd_buf == NULL)
	365	goto fail;
	366	if (use_current_pos) {
e9ce8d39	367	/*
b061a43b A	368	* Read the first batch of directory entries
	369	* to prime dd_seek. This also checks if the
	370	* fd passed to fdopendir() is a directory.
e9ce8d39	371	*/
ad3c9f2a	372	#if __DARWIN_64_BIT_INO_T
507116e3 A	373	/*
	374	* sufficiently recent kernels when the buffer is large enough,
	375	* will use the last bytes of the buffer to return status.
	376	*
	377	* To support older kernels:
	378	* - make sure it's 0 initialized
	379	* - make sure it's past `dd_size` before reading it
	380	*/
	381	getdirentries64_flags_t *gdeflags =
	382	(getdirentries64_flags_t *)(dirp->dd_buf + dirp->dd_len -
	383	sizeof(getdirentries64_flags_t));
	384	*gdeflags = 0;
b061a43b A	385	dirp->dd_size = (long)__getdirentries64(dirp->dd_fd,
b061a43b A	386	dirp->dd_buf, dirp->dd_len, &dirp->dd_td->seekoff);
507116e3 A	387	if (dirp->dd_size >= 0 &&
	388	dirp->dd_size <= dirp->dd_len - sizeof(getdirentries64_flags_t)) {
	389	if (*gdeflags & GETDIRENTRIES64_EOF) {
	390	dirp->dd_flags \|= __DTF_ATEND;
	391	}
	392	}
ad3c9f2a	393	#else /* !__DARWIN_64_BIT_INO_T */
b061a43b A	394	dirp->dd_size = _getdirentries(dirp->dd_fd,
b061a43b A	395	dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
ad3c9f2a	396	#endif /* __DARWIN_64_BIT_INO_T */
b061a43b A	397	if (dirp->dd_size < 0) {
	398	if (errno == EINVAL)
	399	errno = ENOTDIR;
	400	goto fail;
e9ce8d39	401	}
b061a43b A	402	dirp->dd_flags \|= __DTF_SKIPREAD;
	403	} else {
	404	dirp->dd_size = 0;
ad3c9f2a	405	#if __DARWIN_64_BIT_INO_T
b061a43b	406	dirp->dd_td->seekoff = 0;
ad3c9f2a	407	#else /* !__DARWIN_64_BIT_INO_T */
b061a43b	408	dirp->dd_seek = 0;
ad3c9f2a	409	#endif /* __DARWIN_64_BIT_INO_T */
b061a43b	410	}
e9ce8d39 A	411	}
e9ce8d39 A	412
e9ce8d39	413	return (dirp);
e9ce8d39	414
9385eb3d A	415	fail:
9385eb3d A	416	saved_errno = errno;
b061a43b	417	free(dirp->dd_buf);
9385eb3d	418	free(dirp);
9385eb3d A	419	errno = saved_errno;
9385eb3d A	420	return (NULL);
e9ce8d39	421	}