libarchive/libarchive/archive_read_disk_posix.c

/*-
 * Copyright (c) 2003-2009 Tim Kientzle
 * Copyright (c) 2010-2012 Michihiro NAKAJIMA
 * 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
 *    in this position and unchanged.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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.
 */

/* This is the tree-walking code for POSIX systems. */
#if !defined(_WIN32) || defined(__CYGWIN__)

#include "archive_platform.h"
__FBSDID("$FreeBSD$");

#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_MOUNT_H
#include <sys/mount.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SYS_STATFS_H
#include <sys/statfs.h>
#endif
#ifdef HAVE_SYS_STATVFS_H
#include <sys/statvfs.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_LINUX_MAGIC_H
#include <linux/magic.h>
#endif
#ifdef HAVE_LINUX_FS_H
#include <linux/fs.h>
#endif
/*
 * Some Linux distributions have both linux/ext2_fs.h and ext2fs/ext2_fs.h.
 * As the include guards don't agree, the order of include is important.
 */
#ifdef HAVE_LINUX_EXT2_FS_H
#include <linux/ext2_fs.h>      /* for Linux file flags */
#endif
#if defined(HAVE_EXT2FS_EXT2_FS_H) && !defined(__CYGWIN__)
#include <ext2fs/ext2_fs.h>     /* Linux file flags, broken on Cygwin */
#endif
#ifdef HAVE_DIRECT_H
#include <direct.h>
#endif
#ifdef HAVE_DIRENT_H
#include <dirent.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif

#include "archive.h"
#include "archive_string.h"
#include "archive_entry.h"
#include "archive_private.h"
#include "archive_read_disk_private.h"

#ifndef HAVE_FCHDIR
#error fchdir function required.
#endif
#ifndef O_BINARY
#define O_BINARY	0
#endif
#ifndef O_CLOEXEC
#define O_CLOEXEC	0
#endif

/*-
 * This is a new directory-walking system that addresses a number
 * of problems I've had with fts(3).  In particular, it has no
 * pathname-length limits (other than the size of 'int'), handles
 * deep logical traversals, uses considerably less memory, and has
 * an opaque interface (easier to modify in the future).
 *
 * Internally, it keeps a single list of "tree_entry" items that
 * represent filesystem objects that require further attention.
 * Non-directories are not kept in memory: they are pulled from
 * readdir(), returned to the client, then freed as soon as possible.
 * Any directory entry to be traversed gets pushed onto the stack.
 *
 * There is surprisingly little information that needs to be kept for
 * each item on the stack.  Just the name, depth (represented here as the
 * string length of the parent directory's pathname), and some markers
 * indicating how to get back to the parent (via chdir("..") for a
 * regular dir or via fchdir(2) for a symlink).
 */
/*
 * TODO:
 *    1) Loop checking.
 *    3) Arbitrary logical traversals by closing/reopening intermediate fds.
 */

struct restore_time {
	const char		*name;
	time_t			 mtime;
	long			 mtime_nsec;
	time_t			 atime;
	long			 atime_nsec;
	mode_t			 filetype;
	int			 noatime;
};

struct tree_entry {
	int			 depth;
	struct tree_entry	*next;
	struct tree_entry	*parent;
	struct archive_string	 name;
	size_t			 dirname_length;
	int64_t			 dev;
	int64_t			 ino;
	int			 flags;
	int			 filesystem_id;
	/* How to return back to the parent of a symlink. */
	int			 symlink_parent_fd;
	/* How to restore time of a directory. */
	struct restore_time	 restore_time;
};

struct filesystem {
	int64_t		dev;
	int		synthetic;
	int		remote;
	int		noatime;
#if defined(USE_READDIR_R)
	size_t		name_max;
#endif
	long		incr_xfer_size;
	long		max_xfer_size;
	long		min_xfer_size;
	long		xfer_align;

	/*
	 * Buffer used for reading file contents.
	 */
	/* Exactly allocated memory pointer. */
	unsigned char	*allocation_ptr;
	/* Pointer adjusted to the filesystem alignment . */
	unsigned char	*buff;
	size_t		 buff_size;
};

/* Definitions for tree_entry.flags bitmap. */
#define	isDir		1  /* This entry is a regular directory. */
#define	isDirLink	2  /* This entry is a symbolic link to a directory. */
#define	needsFirstVisit	4  /* This is an initial entry. */
#define	needsDescent	8  /* This entry needs to be previsited. */
#define	needsOpen	16 /* This is a directory that needs to be opened. */
#define	needsAscent	32 /* This entry needs to be postvisited. */

/*
 * Local data for this package.
 */
struct tree {
	struct tree_entry	*stack;
	struct tree_entry	*current;
	DIR			*d;
#define	INVALID_DIR_HANDLE NULL
	struct dirent		*de;
#if defined(USE_READDIR_R)
	struct dirent		*dirent;
	size_t			 dirent_allocated;
#endif
	int			 flags;
	int			 visit_type;
	/* Error code from last failed operation. */
	int			 tree_errno;

	/* Dynamically-sized buffer for holding path */
	struct archive_string	 path;

	/* Last path element */
	const char		*basename;
	/* Leading dir length */
	size_t			 dirname_length;

	int			 depth;
	int			 openCount;
	int			 maxOpenCount;
	int			 initial_dir_fd;
	int			 working_dir_fd;

	struct stat		 lst;
	struct stat		 st;
	int			 descend;
	int			 nlink;
	/* How to restore time of a file. */
	struct restore_time	 restore_time;

	struct entry_sparse {
		int64_t		 length;
		int64_t		 offset;
	}			*sparse_list, *current_sparse;
	int			 sparse_count;
	int			 sparse_list_size;

	char			 initial_symlink_mode;
	char			 symlink_mode;
	struct filesystem	*current_filesystem;
	struct filesystem	*filesystem_table;
	int			 initial_filesystem_id;
	int			 current_filesystem_id;
	int			 max_filesystem_id;
	int			 allocated_filesystem;

	int			 entry_fd;
	int			 entry_eof;
	int64_t			 entry_remaining_bytes;
	int64_t			 entry_total;
	unsigned char		*entry_buff;
	size_t			 entry_buff_size;
};

/* Definitions for tree.flags bitmap. */
#define	hasStat		16 /* The st entry is valid. */
#define	hasLstat	32 /* The lst entry is valid. */
#define	onWorkingDir	64 /* We are on the working dir where we are
			    * reading directory entry at this time. */
#define	needsRestoreTimes 128
#define	onInitialDir	256 /* We are on the initial dir. */

static int
tree_dir_next_posix(struct tree *t);

#ifdef HAVE_DIRENT_D_NAMLEN
/* BSD extension; avoids need for a strlen() call. */
#define	D_NAMELEN(dp)	(dp)->d_namlen
#else
#define	D_NAMELEN(dp)	(strlen((dp)->d_name))
#endif

/* Initiate/terminate a tree traversal. */
static struct tree *tree_open(const char *, int, int);
static struct tree *tree_reopen(struct tree *, const char *, int);
static void tree_close(struct tree *);
static void tree_free(struct tree *);
static void tree_push(struct tree *, const char *, int, int64_t, int64_t,
		struct restore_time *);
static int tree_enter_initial_dir(struct tree *);
static int tree_enter_working_dir(struct tree *);
static int tree_current_dir_fd(struct tree *);

/*
 * tree_next() returns Zero if there is no next entry, non-zero if
 * there is.  Note that directories are visited three times.
 * Directories are always visited first as part of enumerating their
 * parent; that is a "regular" visit.  If tree_descend() is invoked at
 * that time, the directory is added to a work list and will
 * subsequently be visited two more times: once just after descending
 * into the directory ("postdescent") and again just after ascending
 * back to the parent ("postascent").
 *
 * TREE_ERROR_DIR is returned if the descent failed (because the
 * directory couldn't be opened, for instance).  This is returned
 * instead of TREE_POSTDESCENT/TREE_POSTASCENT.  TREE_ERROR_DIR is not a
 * fatal error, but it does imply that the relevant subtree won't be
 * visited.  TREE_ERROR_FATAL is returned for an error that left the
 * traversal completely hosed.  Right now, this is only returned for
 * chdir() failures during ascent.
 */
#define	TREE_REGULAR		1
#define	TREE_POSTDESCENT	2
#define	TREE_POSTASCENT		3
#define	TREE_ERROR_DIR		-1
#define	TREE_ERROR_FATAL	-2

static int tree_next(struct tree *);

/*
 * Return information about the current entry.
 */

/*
 * The current full pathname, length of the full pathname, and a name
 * that can be used to access the file.  Because tree does use chdir
 * extensively, the access path is almost never the same as the full
 * current path.
 *
 * TODO: On platforms that support it, use openat()-style operations
 * to eliminate the chdir() operations entirely while still supporting
 * arbitrarily deep traversals.  This makes access_path troublesome to
 * support, of course, which means we'll need a rich enough interface
 * that clients can function without it.  (In particular, we'll need
 * tree_current_open() that returns an open file descriptor.)
 *
 */
static const char *tree_current_path(struct tree *);
static const char *tree_current_access_path(struct tree *);

/*
 * Request the lstat() or stat() data for the current path.  Since the
 * tree package needs to do some of this anyway, and caches the
 * results, you should take advantage of it here if you need it rather
 * than make a redundant stat() or lstat() call of your own.
 */
static const struct stat *tree_current_stat(struct tree *);
static const struct stat *tree_current_lstat(struct tree *);
static int	tree_current_is_symblic_link_target(struct tree *);

/* The following functions use tricks to avoid a certain number of
 * stat()/lstat() calls. */
/* "is_physical_dir" is equivalent to S_ISDIR(tree_current_lstat()->st_mode) */
static int tree_current_is_physical_dir(struct tree *);
/* "is_dir" is equivalent to S_ISDIR(tree_current_stat()->st_mode) */
static int tree_current_is_dir(struct tree *);
static int update_current_filesystem(struct archive_read_disk *a,
		    int64_t dev);
static int setup_current_filesystem(struct archive_read_disk *);
static int tree_target_is_same_as_parent(struct tree *, const struct stat *);

static int	_archive_read_disk_open(struct archive *, const char *);
static int	_archive_read_free(struct archive *);
static int	_archive_read_close(struct archive *);
static int	_archive_read_data_block(struct archive *,
		    const void **, size_t *, int64_t *);
static int	_archive_read_next_header(struct archive *,
		    struct archive_entry **);
static int	_archive_read_next_header2(struct archive *,
		    struct archive_entry *);
static const char *trivial_lookup_gname(void *, int64_t gid);
static const char *trivial_lookup_uname(void *, int64_t uid);
static int	setup_sparse(struct archive_read_disk *, struct archive_entry *);
static int	close_and_restore_time(int fd, struct tree *,
		    struct restore_time *);
static int	open_on_current_dir(struct tree *, const char *, int);
static int	tree_dup(int);


static struct archive_vtable *
archive_read_disk_vtable(void)
{
	static struct archive_vtable av;
	static int inited = 0;

	if (!inited) {
		av.archive_free = _archive_read_free;
		av.archive_close = _archive_read_close;
		av.archive_read_data_block = _archive_read_data_block;
		av.archive_read_next_header = _archive_read_next_header;
		av.archive_read_next_header2 = _archive_read_next_header2;
		inited = 1;
	}
	return (&av);
}

const char *
archive_read_disk_gname(struct archive *_a, int64_t gid)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	if (ARCHIVE_OK != __archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
		ARCHIVE_STATE_ANY, "archive_read_disk_gname"))
		return (NULL);
	if (a->lookup_gname == NULL)
		return (NULL);
	return ((*a->lookup_gname)(a->lookup_gname_data, gid));
}

const char *
archive_read_disk_uname(struct archive *_a, int64_t uid)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	if (ARCHIVE_OK != __archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
		ARCHIVE_STATE_ANY, "archive_read_disk_uname"))
		return (NULL);
	if (a->lookup_uname == NULL)
		return (NULL);
	return ((*a->lookup_uname)(a->lookup_uname_data, uid));
}

int
archive_read_disk_set_gname_lookup(struct archive *_a,
    void *private_data,
    const char * (*lookup_gname)(void *private, int64_t gid),
    void (*cleanup_gname)(void *private))
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(&a->archive, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_set_gname_lookup");

	if (a->cleanup_gname != NULL && a->lookup_gname_data != NULL)
		(a->cleanup_gname)(a->lookup_gname_data);

	a->lookup_gname = lookup_gname;
	a->cleanup_gname = cleanup_gname;
	a->lookup_gname_data = private_data;
	return (ARCHIVE_OK);
}

int
archive_read_disk_set_uname_lookup(struct archive *_a,
    void *private_data,
    const char * (*lookup_uname)(void *private, int64_t uid),
    void (*cleanup_uname)(void *private))
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(&a->archive, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_set_uname_lookup");

	if (a->cleanup_uname != NULL && a->lookup_uname_data != NULL)
		(a->cleanup_uname)(a->lookup_uname_data);

	a->lookup_uname = lookup_uname;
	a->cleanup_uname = cleanup_uname;
	a->lookup_uname_data = private_data;
	return (ARCHIVE_OK);
}

/*
 * Create a new archive_read_disk object and initialize it with global state.
 */
struct archive *
archive_read_disk_new(void)
{
	struct archive_read_disk *a;

	a = (struct archive_read_disk *)calloc(1, sizeof(*a));
	if (a == NULL)
		return (NULL);
	a->archive.magic = ARCHIVE_READ_DISK_MAGIC;
	a->archive.state = ARCHIVE_STATE_NEW;
	a->archive.vtable = archive_read_disk_vtable();
	a->entry = archive_entry_new2(&a->archive);
	a->lookup_uname = trivial_lookup_uname;
	a->lookup_gname = trivial_lookup_gname;
	a->enable_copyfile = 1;
	a->traverse_mount_points = 1;
	a->open_on_current_dir = open_on_current_dir;
	a->tree_current_dir_fd = tree_current_dir_fd;
	a->tree_enter_working_dir = tree_enter_working_dir;
	return (&a->archive);
}

static int
_archive_read_free(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	int r;

	if (_a == NULL)
		return (ARCHIVE_OK);
	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_free");

	if (a->archive.state != ARCHIVE_STATE_CLOSED)
		r = _archive_read_close(&a->archive);
	else
		r = ARCHIVE_OK;

	tree_free(a->tree);
	if (a->cleanup_gname != NULL && a->lookup_gname_data != NULL)
		(a->cleanup_gname)(a->lookup_gname_data);
	if (a->cleanup_uname != NULL && a->lookup_uname_data != NULL)
		(a->cleanup_uname)(a->lookup_uname_data);
	archive_string_free(&a->archive.error_string);
	archive_entry_free(a->entry);
	a->archive.magic = 0;
	__archive_clean(&a->archive);
	free(a);
	return (r);
}

static int
_archive_read_close(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_close");

	if (a->archive.state != ARCHIVE_STATE_FATAL)
		a->archive.state = ARCHIVE_STATE_CLOSED;

	tree_close(a->tree);

	return (ARCHIVE_OK);
}

static void
setup_symlink_mode(struct archive_read_disk *a, char symlink_mode,
    int follow_symlinks)
{
	a->symlink_mode = symlink_mode;
	a->follow_symlinks = follow_symlinks;
	if (a->tree != NULL) {
		a->tree->initial_symlink_mode = a->symlink_mode;
		a->tree->symlink_mode = a->symlink_mode;
	}
}

int
archive_read_disk_set_symlink_logical(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_set_symlink_logical");
	setup_symlink_mode(a, 'L', 1);
	return (ARCHIVE_OK);
}

int
archive_read_disk_set_symlink_physical(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_set_symlink_physical");
	setup_symlink_mode(a, 'P', 0);
	return (ARCHIVE_OK);
}

int
archive_read_disk_set_symlink_hybrid(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_set_symlink_hybrid");
	setup_symlink_mode(a, 'H', 1);/* Follow symlinks initially. */
	return (ARCHIVE_OK);
}

int
archive_read_disk_set_atime_restored(struct archive *_a)
{
#ifndef HAVE_UTIMES
	static int warning_done = 0;
#endif
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_restore_atime");
#ifdef HAVE_UTIMES
	a->restore_time = 1;
	if (a->tree != NULL)
		a->tree->flags |= needsRestoreTimes;
	return (ARCHIVE_OK);
#else
	if (warning_done)
		/* Warning was already emitted; suppress further warnings. */
		return (ARCHIVE_OK);

	archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
	    "Cannot restore access time on this system");
	warning_done = 1;
	return (ARCHIVE_WARN);
#endif
}

int
archive_read_disk_set_behavior(struct archive *_a, int flags)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	int r = ARCHIVE_OK;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_honor_nodump");

	if (flags & ARCHIVE_READDISK_RESTORE_ATIME)
		r = archive_read_disk_set_atime_restored(_a);
	else {
		a->restore_time = 0;
		if (a->tree != NULL)
			a->tree->flags &= ~needsRestoreTimes;
	}
	if (flags & ARCHIVE_READDISK_HONOR_NODUMP)
		a->honor_nodump = 1;
	else
		a->honor_nodump = 0;
	if (flags & ARCHIVE_READDISK_MAC_COPYFILE)
		a->enable_copyfile = 1;
	else
		a->enable_copyfile = 0;
	if (flags & ARCHIVE_READDISK_NO_TRAVERSE_MOUNTS)
		a->traverse_mount_points = 0;
	else
		a->traverse_mount_points = 1;
	if (flags & ARCHIVE_READDISK_NO_XATTR)
		a->suppress_xattr = 1;
	else
		a->suppress_xattr = 0;
	return (r);
}

/*
 * Trivial implementations of gname/uname lookup functions.
 * These are normally overridden by the client, but these stub
 * versions ensure that we always have something that works.
 */
static const char *
trivial_lookup_gname(void *private_data, int64_t gid)
{
	(void)private_data; /* UNUSED */
	(void)gid; /* UNUSED */
	return (NULL);
}

static const char *
trivial_lookup_uname(void *private_data, int64_t uid)
{
	(void)private_data; /* UNUSED */
	(void)uid; /* UNUSED */
	return (NULL);
}

/*
 * Allocate memory for the reading buffer adjusted to the filesystem
 * alignment.
 */
static int
setup_suitable_read_buffer(struct archive_read_disk *a)
{
	struct tree *t = a->tree;
	struct filesystem *cf = t->current_filesystem;
	size_t asize;
	size_t s;

	if (cf->allocation_ptr == NULL) {
		/* If we couldn't get a filesystem alignment,
		 * we use 4096 as default value but we won't use
		 * O_DIRECT to open() and openat() operations. */
		long xfer_align = (cf->xfer_align == -1)?4096:cf->xfer_align;

		if (cf->max_xfer_size != -1)
			asize = cf->max_xfer_size + xfer_align;
		else {
			long incr = cf->incr_xfer_size;
			/* Some platform does not set a proper value to
			 * incr_xfer_size.*/
			if (incr < 0)
				incr = cf->min_xfer_size;
			if (cf->min_xfer_size < 0) {
				incr = xfer_align;
				asize = xfer_align;
			} else
				asize = cf->min_xfer_size;

			/* Increase a buffer size up to 64K bytes in
			 * a proper incremant size. */
			while (asize < 1024*64)
				asize += incr;
			/* Take a margin to adjust to the filesystem
			 * alignment. */
			asize += xfer_align;
		}
		cf->allocation_ptr = malloc(asize);
		if (cf->allocation_ptr == NULL) {
			archive_set_error(&a->archive, ENOMEM,
			    "Couldn't allocate memory");
			a->archive.state = ARCHIVE_STATE_FATAL;
			return (ARCHIVE_FATAL);
		}

		/*
		 * Calculate proper address for the filesystem.
		 */
		s = (uintptr_t)cf->allocation_ptr;
		s %= xfer_align;
		if (s > 0)
			s = xfer_align - s;

		/*
		 * Set a read buffer pointer in the proper alignment of
		 * the current filesystem.
		 */
		cf->buff = cf->allocation_ptr + s;
		cf->buff_size = asize - xfer_align;
	}
	return (ARCHIVE_OK);
}

static int
_archive_read_data_block(struct archive *_a, const void **buff,
    size_t *size, int64_t *offset)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	struct tree *t = a->tree;
	int r;
	ssize_t bytes;
	size_t buffbytes;
	int empty_sparse_region = 0;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC, ARCHIVE_STATE_DATA,
	    "archive_read_data_block");

	if (t->entry_eof || t->entry_remaining_bytes <= 0) {
		r = ARCHIVE_EOF;
		goto abort_read_data;
	}

	/*
	 * Open the current file.
	 */
	if (t->entry_fd < 0) {
		int flags = O_RDONLY | O_BINARY | O_CLOEXEC;

		/*
		 * Eliminate or reduce cache effects if we can.
		 *
		 * Carefully consider this to be enabled.
		 */
#if defined(O_DIRECT) && 0/* Disabled for now */
		if (t->current_filesystem->xfer_align != -1 &&
		    t->nlink == 1)
			flags |= O_DIRECT;
#endif
#if defined(O_NOATIME)
		/*
		 * Linux has O_NOATIME flag; use it if we need.
		 */
		if ((t->flags & needsRestoreTimes) != 0 &&
		    t->restore_time.noatime == 0)
			flags |= O_NOATIME;
		do {
#endif
			t->entry_fd = open_on_current_dir(t,
			    tree_current_access_path(t), flags);
			__archive_ensure_cloexec_flag(t->entry_fd);
#if defined(O_NOATIME)
			/*
			 * When we did open the file with O_NOATIME flag,
			 * if successful, set 1 to t->restore_time.noatime
			 * not to restore an atime of the file later.
			 * if failed by EPERM, retry it without O_NOATIME flag.
			 */
			if (flags & O_NOATIME) {
				if (t->entry_fd >= 0)
					t->restore_time.noatime = 1;
				else if (errno == EPERM) {
					flags &= ~O_NOATIME;
					continue;
				}
			}
		} while (0);
#endif
		if (t->entry_fd < 0) {
			archive_set_error(&a->archive, errno,
			    "Couldn't open %s", tree_current_path(t));
			r = ARCHIVE_FAILED;
			tree_enter_initial_dir(t);
			goto abort_read_data;
		}
		tree_enter_initial_dir(t);
	}

	/*
	 * Allocate read buffer if not allocated.
	 */
	if (t->current_filesystem->allocation_ptr == NULL) {
		r = setup_suitable_read_buffer(a);
		if (r != ARCHIVE_OK) {
			a->archive.state = ARCHIVE_STATE_FATAL;
			goto abort_read_data;
		}
	}
	t->entry_buff = t->current_filesystem->buff;
	t->entry_buff_size = t->current_filesystem->buff_size;

	buffbytes = t->entry_buff_size;
	if ((int64_t)buffbytes > t->current_sparse->length)
		buffbytes = t->current_sparse->length;

	if (t->current_sparse->length == 0)
		empty_sparse_region = 1;

	/*
	 * Skip hole.
	 * TODO: Should we consider t->current_filesystem->xfer_align?
	 */
	if (t->current_sparse->offset > t->entry_total) {
		if (lseek(t->entry_fd,
		    (off_t)t->current_sparse->offset, SEEK_SET) < 0) {
			archive_set_error(&a->archive, errno, "Seek error");
			r = ARCHIVE_FATAL;
			a->archive.state = ARCHIVE_STATE_FATAL;
			goto abort_read_data;
		}
		bytes = t->current_sparse->offset - t->entry_total;
		t->entry_remaining_bytes -= bytes;
		t->entry_total += bytes;
	}

	/*
	 * Read file contents.
	 */
	if (buffbytes > 0) {
		bytes = read(t->entry_fd, t->entry_buff, buffbytes);
		if (bytes < 0) {
			archive_set_error(&a->archive, errno, "Read error");
			r = ARCHIVE_FATAL;
			a->archive.state = ARCHIVE_STATE_FATAL;
			goto abort_read_data;
		}
	} else
		bytes = 0;
	/*
	 * Return an EOF unless we've read a leading empty sparse region, which
	 * is used to represent fully-sparse files.
	*/
	if (bytes == 0 && !empty_sparse_region) {
		/* Get EOF */
		t->entry_eof = 1;
		r = ARCHIVE_EOF;
		goto abort_read_data;
	}
	*buff = t->entry_buff;
	*size = bytes;
	*offset = t->entry_total;
	t->entry_total += bytes;
	t->entry_remaining_bytes -= bytes;
	if (t->entry_remaining_bytes == 0) {
		/* Close the current file descriptor */
		close_and_restore_time(t->entry_fd, t, &t->restore_time);
		t->entry_fd = -1;
		t->entry_eof = 1;
	}
	t->current_sparse->offset += bytes;
	t->current_sparse->length -= bytes;
	if (t->current_sparse->length == 0 && !t->entry_eof)
		t->current_sparse++;
	return (ARCHIVE_OK);

abort_read_data:
	*buff = NULL;
	*size = 0;
	*offset = t->entry_total;
	if (t->entry_fd >= 0) {
		/* Close the current file descriptor */
		close_and_restore_time(t->entry_fd, t, &t->restore_time);
		t->entry_fd = -1;
	}
	return (r);
}

static int
next_entry(struct archive_read_disk *a, struct tree *t,
    struct archive_entry *entry)
{
	const struct stat *st; /* info to use for this entry */
	const struct stat *lst;/* lstat() information */
	const char *name;
	int descend, r;

	st = NULL;
	lst = NULL;
	t->descend = 0;
	do {
		switch (tree_next(t)) {
		case TREE_ERROR_FATAL:
			archive_set_error(&a->archive, t->tree_errno,
			    "%s: Unable to continue traversing directory tree",
			    tree_current_path(t));
			a->archive.state = ARCHIVE_STATE_FATAL;
			tree_enter_initial_dir(t);
			return (ARCHIVE_FATAL);
		case TREE_ERROR_DIR:
			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
			    "%s: Couldn't visit directory",
			    tree_current_path(t));
			tree_enter_initial_dir(t);
			return (ARCHIVE_FAILED);
		case 0:
			tree_enter_initial_dir(t);
			return (ARCHIVE_EOF);
		case TREE_POSTDESCENT:
		case TREE_POSTASCENT:
			break;
		case TREE_REGULAR:
			lst = tree_current_lstat(t);
			if (lst == NULL) {
				archive_set_error(&a->archive, errno,
				    "%s: Cannot stat",
				    tree_current_path(t));
				tree_enter_initial_dir(t);
				return (ARCHIVE_FAILED);
			}
			break;
		}
	} while (lst == NULL);

#ifdef __APPLE__
	if (a->enable_copyfile) {
		/* If we're using copyfile(), ignore "._XXX" files. */
		const char *bname = strrchr(tree_current_path(t), '/');
		if (bname == NULL)
			bname = tree_current_path(t);
		else
			++bname;
		if (bname[0] == '.' && bname[1] == '_')
			return (ARCHIVE_RETRY);
	}
#endif

	archive_entry_copy_pathname(entry, tree_current_path(t));
	/*
	 * Perform path matching.
	 */
	if (a->matching) {
		r = archive_match_path_excluded(a->matching, entry);
		if (r < 0) {
			archive_set_error(&(a->archive), errno,
			    "Failed : %s", archive_error_string(a->matching));
			return (r);
		}
		if (r) {
			if (a->excluded_cb_func)
				a->excluded_cb_func(&(a->archive),
				    a->excluded_cb_data, entry);
			return (ARCHIVE_RETRY);
		}
	}

	/*
	 * Distinguish 'L'/'P'/'H' symlink following.
	 */
	switch(t->symlink_mode) {
	case 'H':
		/* 'H': After the first item, rest like 'P'. */
		t->symlink_mode = 'P';
		/* 'H': First item (from command line) like 'L'. */
		/* FALLTHROUGH */
	case 'L':
		/* 'L': Do descend through a symlink to dir. */
		descend = tree_current_is_dir(t);
		/* 'L': Follow symlinks to files. */
		a->symlink_mode = 'L';
		a->follow_symlinks = 1;
		/* 'L': Archive symlinks as targets, if we can. */
		st = tree_current_stat(t);
		if (st != NULL && !tree_target_is_same_as_parent(t, st))
			break;
		/* If stat fails, we have a broken symlink;
		 * in that case, don't follow the link. */
		/* FALLTHROUGH */
	default:
		/* 'P': Don't descend through a symlink to dir. */
		descend = tree_current_is_physical_dir(t);
		/* 'P': Don't follow symlinks to files. */
		a->symlink_mode = 'P';
		a->follow_symlinks = 0;
		/* 'P': Archive symlinks as symlinks. */
		st = lst;
		break;
	}

	if (update_current_filesystem(a, st->st_dev) != ARCHIVE_OK) {
		a->archive.state = ARCHIVE_STATE_FATAL;
		tree_enter_initial_dir(t);
		return (ARCHIVE_FATAL);
	}
	if (t->initial_filesystem_id == -1)
		t->initial_filesystem_id = t->current_filesystem_id;
	if (!a->traverse_mount_points) {
		if (t->initial_filesystem_id != t->current_filesystem_id)
			descend = 0;
	}
	t->descend = descend;

	/*
	 * Honor nodump flag.
	 * If the file is marked with nodump flag, do not return this entry.
	 */
	if (a->honor_nodump) {
#if defined(HAVE_STRUCT_STAT_ST_FLAGS) && defined(UF_NODUMP)
		if (st->st_flags & UF_NODUMP)
			return (ARCHIVE_RETRY);
#elif defined(EXT2_IOC_GETFLAGS) && defined(EXT2_NODUMP_FL) &&\
      defined(HAVE_WORKING_EXT2_IOC_GETFLAGS)
		if (S_ISREG(st->st_mode) || S_ISDIR(st->st_mode)) {
			int stflags;

			t->entry_fd = open_on_current_dir(t,
			    tree_current_access_path(t),
			    O_RDONLY | O_NONBLOCK | O_CLOEXEC);
			__archive_ensure_cloexec_flag(t->entry_fd);
			if (t->entry_fd >= 0) {
				r = ioctl(t->entry_fd, EXT2_IOC_GETFLAGS,
					&stflags);
				if (r == 0 && (stflags & EXT2_NODUMP_FL) != 0)
					return (ARCHIVE_RETRY);
			}
		}
#endif
	}

	archive_entry_copy_stat(entry, st);

	/* Save the times to be restored. This must be in before
	 * calling archive_read_disk_descend() or any chance of it,
	 * especially, invoking a callback. */
	t->restore_time.mtime = archive_entry_mtime(entry);
	t->restore_time.mtime_nsec = archive_entry_mtime_nsec(entry);
	t->restore_time.atime = archive_entry_atime(entry);
	t->restore_time.atime_nsec = archive_entry_atime_nsec(entry);
	t->restore_time.filetype = archive_entry_filetype(entry);
	t->restore_time.noatime = t->current_filesystem->noatime;

	/*
	 * Perform time matching.
	 */
	if (a->matching) {
		r = archive_match_time_excluded(a->matching, entry);
		if (r < 0) {
			archive_set_error(&(a->archive), errno,
			    "Failed : %s", archive_error_string(a->matching));
			return (r);
		}
		if (r) {
			if (a->excluded_cb_func)
				a->excluded_cb_func(&(a->archive),
				    a->excluded_cb_data, entry);
			return (ARCHIVE_RETRY);
		}
	}

	/* Lookup uname/gname */
	name = archive_read_disk_uname(&(a->archive), archive_entry_uid(entry));
	if (name != NULL)
		archive_entry_copy_uname(entry, name);
	name = archive_read_disk_gname(&(a->archive), archive_entry_gid(entry));
	if (name != NULL)
		archive_entry_copy_gname(entry, name);

	/*
	 * Perform owner matching.
	 */
	if (a->matching) {
		r = archive_match_owner_excluded(a->matching, entry);
		if (r < 0) {
			archive_set_error(&(a->archive), errno,
			    "Failed : %s", archive_error_string(a->matching));
			return (r);
		}
		if (r) {
			if (a->excluded_cb_func)
				a->excluded_cb_func(&(a->archive),
				    a->excluded_cb_data, entry);
			return (ARCHIVE_RETRY);
		}
	}

	/*
	 * Invoke a meta data filter callback.
	 */
	if (a->metadata_filter_func) {
		if (!a->metadata_filter_func(&(a->archive),
		    a->metadata_filter_data, entry))
			return (ARCHIVE_RETRY);
	}

	/*
	 * Populate the archive_entry with metadata from the disk.
	 */
	archive_entry_copy_sourcepath(entry, tree_current_access_path(t));
	r = archive_read_disk_entry_from_file(&(a->archive), entry,
		t->entry_fd, st);

	return (r);
}

static int
_archive_read_next_header(struct archive *_a, struct archive_entry **entryp)
{
	int ret;
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	*entryp = NULL;
	ret = _archive_read_next_header2(_a, a->entry);
	*entryp = a->entry;
	return ret;
}

static int
_archive_read_next_header2(struct archive *_a, struct archive_entry *entry)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	struct tree *t;
	int r;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
	    "archive_read_next_header2");

	t = a->tree;
	if (t->entry_fd >= 0) {
		close_and_restore_time(t->entry_fd, t, &t->restore_time);
		t->entry_fd = -1;
	}

	for (;;) {
		r = next_entry(a, t, entry);
		if (t->entry_fd >= 0) {
			close(t->entry_fd);
			t->entry_fd = -1;
		}

		if (r == ARCHIVE_RETRY) {
			archive_entry_clear(entry);
			continue;
		}
		break;
	}

	/* Return to the initial directory. */
	tree_enter_initial_dir(t);

	/*
	 * EOF and FATAL are persistent at this layer.  By
	 * modifying the state, we guarantee that future calls to
	 * read a header or read data will fail.
	 */
	switch (r) {
	case ARCHIVE_EOF:
		a->archive.state = ARCHIVE_STATE_EOF;
		break;
	case ARCHIVE_OK:
	case ARCHIVE_WARN:
		/* Overwrite the sourcepath based on the initial directory. */
		archive_entry_copy_sourcepath(entry, tree_current_path(t));
		t->entry_total = 0;
		if (archive_entry_filetype(entry) == AE_IFREG) {
			t->nlink = archive_entry_nlink(entry);
			t->entry_remaining_bytes = archive_entry_size(entry);
			t->entry_eof = (t->entry_remaining_bytes == 0)? 1: 0;
			if (!t->entry_eof &&
			    setup_sparse(a, entry) != ARCHIVE_OK)
				return (ARCHIVE_FATAL);
		} else {
			t->entry_remaining_bytes = 0;
			t->entry_eof = 1;
		}
		a->archive.state = ARCHIVE_STATE_DATA;
		break;
	case ARCHIVE_RETRY:
		break;
	case ARCHIVE_FATAL:
		a->archive.state = ARCHIVE_STATE_FATAL;
		break;
	}

	__archive_reset_read_data(&a->archive);
	return (r);
}

static int
setup_sparse(struct archive_read_disk *a, struct archive_entry *entry)
{
	struct tree *t = a->tree;
	int64_t length, offset;
	int i;

	t->sparse_count = archive_entry_sparse_reset(entry);
	if (t->sparse_count+1 > t->sparse_list_size) {
		free(t->sparse_list);
		t->sparse_list_size = t->sparse_count + 1;
		t->sparse_list = malloc(sizeof(t->sparse_list[0]) *
		    t->sparse_list_size);
		if (t->sparse_list == NULL) {
			t->sparse_list_size = 0;
			archive_set_error(&a->archive, ENOMEM,
			    "Can't allocate data");
			a->archive.state = ARCHIVE_STATE_FATAL;
			return (ARCHIVE_FATAL);
		}
	}
	for (i = 0; i < t->sparse_count; i++) {
		archive_entry_sparse_next(entry, &offset, &length);
		t->sparse_list[i].offset = offset;
		t->sparse_list[i].length = length;
	}
	if (i == 0) {
		t->sparse_list[i].offset = 0;
		t->sparse_list[i].length = archive_entry_size(entry);
	} else {
		t->sparse_list[i].offset = archive_entry_size(entry);
		t->sparse_list[i].length = 0;
	}
	t->current_sparse = t->sparse_list;

	return (ARCHIVE_OK);
}

int
archive_read_disk_set_matching(struct archive *_a, struct archive *_ma,
    void (*_excluded_func)(struct archive *, void *, struct archive_entry *),
    void *_client_data)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_ANY, "archive_read_disk_set_matching");
	a->matching = _ma;
	a->excluded_cb_func = _excluded_func;
	a->excluded_cb_data = _client_data;
	return (ARCHIVE_OK);
}

int
archive_read_disk_set_metadata_filter_callback(struct archive *_a,
    int (*_metadata_filter_func)(struct archive *, void *,
    struct archive_entry *), void *_client_data)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC, ARCHIVE_STATE_ANY,
	    "archive_read_disk_set_metadata_filter_callback");

	a->metadata_filter_func = _metadata_filter_func;
	a->metadata_filter_data = _client_data;
	return (ARCHIVE_OK);
}

int
archive_read_disk_can_descend(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	struct tree *t = a->tree;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
	    "archive_read_disk_can_descend");

	return (t->visit_type == TREE_REGULAR && t->descend);
}

/*
 * Called by the client to mark the directory just returned from
 * tree_next() as needing to be visited.
 */
int
archive_read_disk_descend(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	struct tree *t = a->tree;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
	    "archive_read_disk_descend");

	if (t->visit_type != TREE_REGULAR || !t->descend)
		return (ARCHIVE_OK);

	if (tree_current_is_physical_dir(t)) {
		tree_push(t, t->basename, t->current_filesystem_id,
		    t->lst.st_dev, t->lst.st_ino, &t->restore_time);
		t->stack->flags |= isDir;
	} else if (tree_current_is_dir(t)) {
		tree_push(t, t->basename, t->current_filesystem_id,
		    t->st.st_dev, t->st.st_ino, &t->restore_time);
		t->stack->flags |= isDirLink;
	}
	t->descend = 0;
	return (ARCHIVE_OK);
}

int
archive_read_disk_open(struct archive *_a, const char *pathname)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_NEW | ARCHIVE_STATE_CLOSED,
	    "archive_read_disk_open");
	archive_clear_error(&a->archive);

	return (_archive_read_disk_open(_a, pathname));
}

int
archive_read_disk_open_w(struct archive *_a, const wchar_t *pathname)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;
	struct archive_string path;
	int ret;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC,
	    ARCHIVE_STATE_NEW | ARCHIVE_STATE_CLOSED,
	    "archive_read_disk_open_w");
	archive_clear_error(&a->archive);

	/* Make a char string from a wchar_t string. */
	archive_string_init(&path);
	if (archive_string_append_from_wcs(&path, pathname,
	    wcslen(pathname)) != 0) {
		if (errno == ENOMEM)
			archive_set_error(&a->archive, ENOMEM,
			    "Can't allocate memory");
		else
			archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
			    "Can't convert a path to a char string");
		a->archive.state = ARCHIVE_STATE_FATAL;
		ret = ARCHIVE_FATAL;
	} else
		ret = _archive_read_disk_open(_a, path.s);

	archive_string_free(&path);
	return (ret);
}

static int
_archive_read_disk_open(struct archive *_a, const char *pathname)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	if (a->tree != NULL)
		a->tree = tree_reopen(a->tree, pathname, a->restore_time);
	else
		a->tree = tree_open(pathname, a->symlink_mode,
		    a->restore_time);
	if (a->tree == NULL) {
		archive_set_error(&a->archive, ENOMEM,
		    "Can't allocate tar data");
		a->archive.state = ARCHIVE_STATE_FATAL;
		return (ARCHIVE_FATAL);
	}
	a->archive.state = ARCHIVE_STATE_HEADER;

	return (ARCHIVE_OK);
}

/*
 * Return a current filesystem ID which is index of the filesystem entry
 * you've visited through archive_read_disk.
 */
int
archive_read_disk_current_filesystem(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC, ARCHIVE_STATE_DATA,
	    "archive_read_disk_current_filesystem");

	return (a->tree->current_filesystem_id);
}

static int
update_current_filesystem(struct archive_read_disk *a, int64_t dev)
{
	struct tree *t = a->tree;
	int i, fid;

	if (t->current_filesystem != NULL &&
	    t->current_filesystem->dev == dev)
		return (ARCHIVE_OK);

	for (i = 0; i < t->max_filesystem_id; i++) {
		if (t->filesystem_table[i].dev == dev) {
			/* There is the filesystem ID we've already generated. */
			t->current_filesystem_id = i;
			t->current_filesystem = &(t->filesystem_table[i]);
			return (ARCHIVE_OK);
		}
	}

	/*
	 * This is the new filesystem which we have to generate a new ID for.
	 */
	fid = t->max_filesystem_id++;
	if (t->max_filesystem_id > t->allocated_filesystem) {
		size_t s;
		void *p;

		s = t->max_filesystem_id * 2;
		p = realloc(t->filesystem_table,
		        s * sizeof(*t->filesystem_table));
		if (p == NULL) {
			archive_set_error(&a->archive, ENOMEM,
			    "Can't allocate tar data");
			return (ARCHIVE_FATAL);
		}
		t->filesystem_table = (struct filesystem *)p;
		t->allocated_filesystem = s;
	}
	t->current_filesystem_id = fid;
	t->current_filesystem = &(t->filesystem_table[fid]);
	t->current_filesystem->dev = dev;
	t->current_filesystem->allocation_ptr = NULL;
	t->current_filesystem->buff = NULL;

	/* Setup the current filesystem properties which depend on
	 * platform specific. */
	return (setup_current_filesystem(a));
}

/*
 * Returns 1 if current filesystem is generated filesystem, 0 if it is not
 * or -1 if it is unknown.
 */
int
archive_read_disk_current_filesystem_is_synthetic(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC, ARCHIVE_STATE_DATA,
	    "archive_read_disk_current_filesystem");

	return (a->tree->current_filesystem->synthetic);
}

/*
 * Returns 1 if current filesystem is remote filesystem, 0 if it is not
 * or -1 if it is unknown.
 */
int
archive_read_disk_current_filesystem_is_remote(struct archive *_a)
{
	struct archive_read_disk *a = (struct archive_read_disk *)_a;

	archive_check_magic(_a, ARCHIVE_READ_DISK_MAGIC, ARCHIVE_STATE_DATA,
	    "archive_read_disk_current_filesystem");

	return (a->tree->current_filesystem->remote);
}

#if defined(_PC_REC_INCR_XFER_SIZE) && defined(_PC_REC_MAX_XFER_SIZE) &&\
	defined(_PC_REC_MIN_XFER_SIZE) && defined(_PC_REC_XFER_ALIGN)
static int
get_xfer_size(struct tree *t, int fd, const char *path)
{
	t->current_filesystem->xfer_align = -1;
	errno = 0;
	if (fd >= 0) {
		t->current_filesystem->incr_xfer_size =
		    fpathconf(fd, _PC_REC_INCR_XFER_SIZE);
		t->current_filesystem->max_xfer_size =
		    fpathconf(fd, _PC_REC_MAX_XFER_SIZE);
		t->current_filesystem->min_xfer_size =
		    fpathconf(fd, _PC_REC_MIN_XFER_SIZE);
		t->current_filesystem->xfer_align =
		    fpathconf(fd, _PC_REC_XFER_ALIGN);
	} else if (path != NULL) {
		t->current_filesystem->incr_xfer_size =
		    pathconf(path, _PC_REC_INCR_XFER_SIZE);
		t->current_filesystem->max_xfer_size =
		    pathconf(path, _PC_REC_MAX_XFER_SIZE);
		t->current_filesystem->min_xfer_size =
		    pathconf(path, _PC_REC_MIN_XFER_SIZE);
		t->current_filesystem->xfer_align =
		    pathconf(path, _PC_REC_XFER_ALIGN);
	}
	/* At least we need an alignment size. */
	if (t->current_filesystem->xfer_align == -1)
		return ((errno == EINVAL)?1:-1);
	else
		return (0);
}
#else
static int
get_xfer_size(struct tree *t, int fd, const char *path)
{
	(void)t; /* UNUSED */
	(void)fd; /* UNUSED */
	(void)path; /* UNUSED */
	return (1);/* Not supported */
}
#endif

#if defined(HAVE_STATFS) && defined(HAVE_FSTATFS) && defined(MNT_LOCAL) \
	&& !defined(ST_LOCAL)

/*
 * Gather current filesystem properties on FreeBSD, OpenBSD and Mac OS X.
 */
static int
setup_current_filesystem(struct archive_read_disk *a)
{
	struct tree *t = a->tree;
	struct statfs sfs;
#if defined(HAVE_GETVFSBYNAME) && defined(VFCF_SYNTHETIC)
/* TODO: configure should set GETVFSBYNAME_ARG_TYPE to make
 * this accurate; some platforms have both and we need the one that's
 * used by getvfsbyname()
 *
 * Then the following would become:
 *  #if defined(GETVFSBYNAME_ARG_TYPE)
 *   GETVFSBYNAME_ARG_TYPE vfc;
 *  #endif
 */
#  if defined(HAVE_STRUCT_XVFSCONF)
	struct xvfsconf vfc;
#  else
	struct vfsconf vfc;
#  endif
#endif
	int r, xr = 0;
#if !defined(HAVE_STRUCT_STATFS_F_NAMEMAX)
	long nm;
#endif

	t->current_filesystem->synthetic = -1;
	t->current_filesystem->remote = -1;
	if (tree_current_is_symblic_link_target(t)) {
#if defined(HAVE_OPENAT)
		/*
		 * Get file system statistics on any directory
		 * where current is.
		 */
		int fd = openat(tree_current_dir_fd(t),
		    tree_current_access_path(t), O_RDONLY | O_CLOEXEC);
		__archive_ensure_cloexec_flag(fd);
		if (fd < 0) {
			archive_set_error(&a->archive, errno,
			    "openat failed");
			return (ARCHIVE_FAILED);
		}
		r = fstatfs(fd, &sfs);
		if (r == 0)
			xr = get_xfer_size(t, fd, NULL);
		close(fd);
#else
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
		r = statfs(tree_current_access_path(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, tree_current_access_path(t));
#endif
	} else {
		r = fstatfs(tree_current_dir_fd(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, tree_current_dir_fd(t), NULL);
	}
	if (r == -1 || xr == -1) {
		archive_set_error(&a->archive, errno, "statfs failed");
		return (ARCHIVE_FAILED);
	} else if (xr == 1) {
		/* pathconf(_PC_REX_*) operations are not supported. */
		t->current_filesystem->xfer_align = sfs.f_bsize;
		t->current_filesystem->max_xfer_size = -1;
		t->current_filesystem->min_xfer_size = sfs.f_iosize;
		t->current_filesystem->incr_xfer_size = sfs.f_iosize;
	}
	if (sfs.f_flags & MNT_LOCAL)
		t->current_filesystem->remote = 0;
	else
		t->current_filesystem->remote = 1;

#if defined(HAVE_GETVFSBYNAME) && defined(VFCF_SYNTHETIC)
	r = getvfsbyname(sfs.f_fstypename, &vfc);
	if (r == -1) {
		archive_set_error(&a->archive, errno, "getvfsbyname failed");
		return (ARCHIVE_FAILED);
	}
	if (vfc.vfc_flags & VFCF_SYNTHETIC)
		t->current_filesystem->synthetic = 1;
	else
		t->current_filesystem->synthetic = 0;
#endif

#if defined(MNT_NOATIME)
	if (sfs.f_flags & MNT_NOATIME)
		t->current_filesystem->noatime = 1;
	else
#endif
		t->current_filesystem->noatime = 0;

#if defined(USE_READDIR_R)
	/* Set maximum filename length. */
#if defined(HAVE_STRUCT_STATFS_F_NAMEMAX)
	t->current_filesystem->name_max = sfs.f_namemax;
#else
# if defined(_PC_NAME_MAX)
	/* Mac OS X does not have f_namemax in struct statfs. */
	if (tree_current_is_symblic_link_target(t)) {
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
		nm = pathconf(tree_current_access_path(t), _PC_NAME_MAX);
	} else
		nm = fpathconf(tree_current_dir_fd(t), _PC_NAME_MAX);
# else
	nm = -1;
# endif
	if (nm == -1)
		t->current_filesystem->name_max = NAME_MAX;
	else
		t->current_filesystem->name_max = nm;
#endif
#endif /* USE_READDIR_R */
	return (ARCHIVE_OK);
}

#elif (defined(HAVE_STATVFS) || defined(HAVE_FSTATVFS)) && defined(ST_LOCAL)

/*
 * Gather current filesystem properties on NetBSD
 */
static int
setup_current_filesystem(struct archive_read_disk *a)
{
	struct tree *t = a->tree;
	struct statvfs sfs;
	int r, xr = 0;

	t->current_filesystem->synthetic = -1;
	if (tree_enter_working_dir(t) != 0) {
		archive_set_error(&a->archive, errno, "fchdir failed");
		return (ARCHIVE_FAILED);
	}
	if (tree_current_is_symblic_link_target(t)) {
		r = statvfs(tree_current_access_path(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, tree_current_access_path(t));
	} else {
#ifdef HAVE_FSTATVFS
		r = fstatvfs(tree_current_dir_fd(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, tree_current_dir_fd(t), NULL);
#else
		r = statvfs(".", &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, ".");
#endif
	}
	if (r == -1 || xr == -1) {
		t->current_filesystem->remote = -1;
		archive_set_error(&a->archive, errno, "statvfs failed");
		return (ARCHIVE_FAILED);
	} else if (xr == 1) {
		/* Usuall come here unless NetBSD supports _PC_REC_XFER_ALIGN
		 * for pathconf() function. */
		t->current_filesystem->xfer_align = sfs.f_frsize;
		t->current_filesystem->max_xfer_size = -1;
#if defined(HAVE_STRUCT_STATVFS_F_IOSIZE)
		t->current_filesystem->min_xfer_size = sfs.f_iosize;
		t->current_filesystem->incr_xfer_size = sfs.f_iosize;
#else
		t->current_filesystem->min_xfer_size = sfs.f_bsize;
		t->current_filesystem->incr_xfer_size = sfs.f_bsize;
#endif
	}
	if (sfs.f_flag & ST_LOCAL)
		t->current_filesystem->remote = 0;
	else
		t->current_filesystem->remote = 1;

#if defined(ST_NOATIME)
	if (sfs.f_flag & ST_NOATIME)
		t->current_filesystem->noatime = 1;
	else
#endif
		t->current_filesystem->noatime = 0;

	/* Set maximum filename length. */
	t->current_filesystem->name_max = sfs.f_namemax;
	return (ARCHIVE_OK);
}

#elif defined(HAVE_SYS_STATFS_H) && defined(HAVE_LINUX_MAGIC_H) &&\
	defined(HAVE_STATFS) && defined(HAVE_FSTATFS)
/*
 * Note: statfs is deprecated since LSB 3.2
 */

#ifndef CIFS_SUPER_MAGIC
#define CIFS_SUPER_MAGIC 0xFF534D42
#endif
#ifndef DEVFS_SUPER_MAGIC
#define DEVFS_SUPER_MAGIC 0x1373
#endif

/*
 * Gather current filesystem properties on Linux
 */
static int
setup_current_filesystem(struct archive_read_disk *a)
{
	struct tree *t = a->tree;
	struct statfs sfs;
#if defined(HAVE_STATVFS)
	struct statvfs svfs;
#endif
	int r, vr = 0, xr = 0;

	if (tree_current_is_symblic_link_target(t)) {
#if defined(HAVE_OPENAT)
		/*
		 * Get file system statistics on any directory
		 * where current is.
		 */
		int fd = openat(tree_current_dir_fd(t),
		    tree_current_access_path(t), O_RDONLY | O_CLOEXEC);
		__archive_ensure_cloexec_flag(fd);
		if (fd < 0) {
			archive_set_error(&a->archive, errno,
			    "openat failed");
			return (ARCHIVE_FAILED);
		}
#if defined(HAVE_FSTATVFS)
		vr = fstatvfs(fd, &svfs);/* for f_flag, mount flags */
#endif
		r = fstatfs(fd, &sfs);
		if (r == 0)
			xr = get_xfer_size(t, fd, NULL);
		close(fd);
#else
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
#if defined(HAVE_STATVFS)
		vr = statvfs(tree_current_access_path(t), &svfs);
#endif
		r = statfs(tree_current_access_path(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, tree_current_access_path(t));
#endif
	} else {
#ifdef HAVE_FSTATFS
#if defined(HAVE_FSTATVFS)
		vr = fstatvfs(tree_current_dir_fd(t), &svfs);
#endif
		r = fstatfs(tree_current_dir_fd(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, tree_current_dir_fd(t), NULL);
#else
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
#if defined(HAVE_STATVFS)
		vr = statvfs(".", &svfs);
#endif
		r = statfs(".", &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, ".");
#endif
	}
	if (r == -1 || xr == -1 || vr == -1) {
		t->current_filesystem->synthetic = -1;
		t->current_filesystem->remote = -1;
		archive_set_error(&a->archive, errno, "statfs failed");
		return (ARCHIVE_FAILED);
	} else if (xr == 1) {
		/* pathconf(_PC_REX_*) operations are not supported. */
#if defined(HAVE_STATVFS)
		t->current_filesystem->xfer_align = svfs.f_frsize;
		t->current_filesystem->max_xfer_size = -1;
		t->current_filesystem->min_xfer_size = svfs.f_bsize;
		t->current_filesystem->incr_xfer_size = svfs.f_bsize;
#else
		t->current_filesystem->xfer_align = sfs.f_frsize;
		t->current_filesystem->max_xfer_size = -1;
		t->current_filesystem->min_xfer_size = sfs.f_bsize;
		t->current_filesystem->incr_xfer_size = sfs.f_bsize;
#endif
	}
	switch (sfs.f_type) {
	case AFS_SUPER_MAGIC:
	case CIFS_SUPER_MAGIC:
	case CODA_SUPER_MAGIC:
	case NCP_SUPER_MAGIC:/* NetWare */
	case NFS_SUPER_MAGIC:
	case SMB_SUPER_MAGIC:
		t->current_filesystem->remote = 1;
		t->current_filesystem->synthetic = 0;
		break;
	case DEVFS_SUPER_MAGIC:
	case PROC_SUPER_MAGIC:
	case USBDEVICE_SUPER_MAGIC:
		t->current_filesystem->remote = 0;
		t->current_filesystem->synthetic = 1;
		break;
	default:
		t->current_filesystem->remote = 0;
		t->current_filesystem->synthetic = 0;
		break;
	}

#if defined(ST_NOATIME)
#if defined(HAVE_STATVFS)
	if (svfs.f_flag & ST_NOATIME)
#else
	if (sfs.f_flag & ST_NOATIME)
#endif
		t->current_filesystem->noatime = 1;
	else
#endif
		t->current_filesystem->noatime = 0;

#if defined(USE_READDIR_R)
	/* Set maximum filename length. */
	t->current_filesystem->name_max = sfs.f_namelen;
#endif
	return (ARCHIVE_OK);
}

#elif defined(HAVE_SYS_STATVFS_H) &&\
	(defined(HAVE_STATVFS) || defined(HAVE_FSTATVFS))

/*
 * Gather current filesystem properties on other posix platform.
 */
static int
setup_current_filesystem(struct archive_read_disk *a)
{
	struct tree *t = a->tree;
	struct statvfs sfs;
	int r, xr = 0;

	t->current_filesystem->synthetic = -1;/* Not supported */
	t->current_filesystem->remote = -1;/* Not supported */
	if (tree_current_is_symblic_link_target(t)) {
#if defined(HAVE_OPENAT)
		/*
		 * Get file system statistics on any directory
		 * where current is.
		 */
		int fd = openat(tree_current_dir_fd(t),
		    tree_current_access_path(t), O_RDONLY | O_CLOEXEC);
		__archive_ensure_cloexec_flag(fd);
		if (fd < 0) {
			archive_set_error(&a->archive, errno,
			    "openat failed");
			return (ARCHIVE_FAILED);
		}
		r = fstatvfs(fd, &sfs);
		if (r == 0)
			xr = get_xfer_size(t, fd, NULL);
		close(fd);
#else
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
		r = statvfs(tree_current_access_path(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, tree_current_access_path(t));
#endif
	} else {
#ifdef HAVE_FSTATVFS
		r = fstatvfs(tree_current_dir_fd(t), &sfs);
		if (r == 0)
			xr = get_xfer_size(t, tree_current_dir_fd(t), NULL);
#else
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
		r = statvfs(".", &sfs);
		if (r == 0)
			xr = get_xfer_size(t, -1, ".");
#endif
	}
	if (r == -1 || xr == -1) {
		t->current_filesystem->synthetic = -1;
		t->current_filesystem->remote = -1;
		archive_set_error(&a->archive, errno, "statvfs failed");
		return (ARCHIVE_FAILED);
	} else if (xr == 1) {
		/* pathconf(_PC_REX_*) operations are not supported. */
		t->current_filesystem->xfer_align = sfs.f_frsize;
		t->current_filesystem->max_xfer_size = -1;
		t->current_filesystem->min_xfer_size = sfs.f_bsize;
		t->current_filesystem->incr_xfer_size = sfs.f_bsize;
	}

#if defined(ST_NOATIME)
	if (sfs.f_flag & ST_NOATIME)
		t->current_filesystem->noatime = 1;
	else
#endif
		t->current_filesystem->noatime = 0;

#if defined(USE_READDIR_R)
	/* Set maximum filename length. */
	t->current_filesystem->name_max = sfs.f_namemax;
#endif
	return (ARCHIVE_OK);
}

#else

/*
 * Generic: Gather current filesystem properties.
 * TODO: Is this generic function really needed?
 */
static int
setup_current_filesystem(struct archive_read_disk *a)
{
	struct tree *t = a->tree;
#if defined(_PC_NAME_MAX) && defined(USE_READDIR_R)
	long nm;
#endif
	t->current_filesystem->synthetic = -1;/* Not supported */
	t->current_filesystem->remote = -1;/* Not supported */
	t->current_filesystem->noatime = 0;
	(void)get_xfer_size(t, -1, ".");/* Dummy call to avoid build error. */
	t->current_filesystem->xfer_align = -1;/* Unknown */
	t->current_filesystem->max_xfer_size = -1;
	t->current_filesystem->min_xfer_size = -1;
	t->current_filesystem->incr_xfer_size = -1;

#if defined(USE_READDIR_R)
	/* Set maximum filename length. */
#  if defined(_PC_NAME_MAX)
	if (tree_current_is_symblic_link_target(t)) {
		if (tree_enter_working_dir(t) != 0) {
			archive_set_error(&a->archive, errno, "fchdir failed");
			return (ARCHIVE_FAILED);
		}
		nm = pathconf(tree_current_access_path(t), _PC_NAME_MAX);
	} else
		nm = fpathconf(tree_current_dir_fd(t), _PC_NAME_MAX);
	if (nm == -1)
#  endif /* _PC_NAME_MAX */
		/*
		 * Some sysmtes (HP-UX or others?) incorrectly defined
		 * NAME_MAX macro to be a smaller value.
		 */
#  if defined(NAME_MAX) && NAME_MAX >= 255
		t->current_filesystem->name_max = NAME_MAX;
#  else
		/* No way to get a trusted value of maximum filename
		 * length. */
		t->current_filesystem->name_max = PATH_MAX;
#  endif /* NAME_MAX */
#  if defined(_PC_NAME_MAX)
	else
		t->current_filesystem->name_max = nm;
#  endif /* _PC_NAME_MAX */
#endif /* USE_READDIR_R */
	return (ARCHIVE_OK);
}

#endif

static int
close_and_restore_time(int fd, struct tree *t, struct restore_time *rt)
{
#ifndef HAVE_UTIMES
	(void)t; /* UNUSED */
	(void)rt; /* UNUSED */
	return (close(fd));
#else
#if defined(HAVE_FUTIMENS) && !defined(__CYGWIN__)
	struct timespec timespecs[2];
#endif
	struct timeval times[2];

	if ((t->flags & needsRestoreTimes) == 0 || rt->noatime) {
		if (fd >= 0)
			return (close(fd));
		else
			return (0);
	}

#if defined(HAVE_FUTIMENS) && !defined(__CYGWIN__)
	timespecs[1].tv_sec = rt->mtime;
	timespecs[1].tv_nsec = rt->mtime_nsec;

	timespecs[0].tv_sec = rt->atime;
	timespecs[0].tv_nsec = rt->atime_nsec;
	/* futimens() is defined in POSIX.1-2008. */
	if (futimens(fd, timespecs) == 0)
		return (close(fd));
#endif

	times[1].tv_sec = rt->mtime;
	times[1].tv_usec = rt->mtime_nsec / 1000;

	times[0].tv_sec = rt->atime;
	times[0].tv_usec = rt->atime_nsec / 1000;

#if !defined(HAVE_FUTIMENS) && defined(HAVE_FUTIMES) && !defined(__CYGWIN__)
	if (futimes(fd, times) == 0)
		return (close(fd));
#endif
	close(fd);
#if defined(HAVE_FUTIMESAT)
	if (futimesat(tree_current_dir_fd(t), rt->name, times) == 0)
		return (0);
#endif
#ifdef HAVE_LUTIMES
	if (lutimes(rt->name, times) != 0)
#else
	if (AE_IFLNK != rt->filetype && utimes(rt->name, times) != 0)
#endif
		return (-1);
#endif
	return (0);
}

static int
open_on_current_dir(struct tree *t, const char *path, int flags)
{
#ifdef HAVE_OPENAT
	return (openat(tree_current_dir_fd(t), path, flags));
#else
	if (tree_enter_working_dir(t) != 0)
		return (-1);
	return (open(path, flags));
#endif
}

static int
tree_dup(int fd)
{
	int new_fd;
#ifdef F_DUPFD_CLOEXEC
	static volatile int can_dupfd_cloexec = 1;

	if (can_dupfd_cloexec) {
		new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
		if (new_fd != -1)
			return (new_fd);
		/* Linux 2.6.18 - 2.6.23 declare F_DUPFD_CLOEXEC,
		 * but it cannot be used. So we have to try dup(). */
		/* We won't try F_DUPFD_CLOEXEC. */
		can_dupfd_cloexec = 0;
	}
#endif /* F_DUPFD_CLOEXEC */
	new_fd = dup(fd);
	__archive_ensure_cloexec_flag(new_fd);
	return (new_fd);
}

/*
 * Add a directory path to the current stack.
 */
static void
tree_push(struct tree *t, const char *path, int filesystem_id,
    int64_t dev, int64_t ino, struct restore_time *rt)
{
	struct tree_entry *te;

	te = calloc(1, sizeof(*te));
	te->next = t->stack;
	te->parent = t->current;
	if (te->parent)
		te->depth = te->parent->depth + 1;
	t->stack = te;
	archive_string_init(&te->name);
	te->symlink_parent_fd = -1;
	archive_strcpy(&te->name, path);
	te->flags = needsDescent | needsOpen | needsAscent;
	te->filesystem_id = filesystem_id;
	te->dev = dev;
	te->ino = ino;
	te->dirname_length = t->dirname_length;
	te->restore_time.name = te->name.s;
	if (rt != NULL) {
		te->restore_time.mtime = rt->mtime;
		te->restore_time.mtime_nsec = rt->mtime_nsec;
		te->restore_time.atime = rt->atime;
		te->restore_time.atime_nsec = rt->atime_nsec;
		te->restore_time.filetype = rt->filetype;
		te->restore_time.noatime = rt->noatime;
	}
}

/*
 * Append a name to the current dir path.
 */
static void
tree_append(struct tree *t, const char *name, size_t name_length)
{
	size_t size_needed;

	t->path.s[t->dirname_length] = '\0';
	t->path.length = t->dirname_length;
	/* Strip trailing '/' from name, unless entire name is "/". */
	while (name_length > 1 && name[name_length - 1] == '/')
		name_length--;

	/* Resize pathname buffer as needed. */
	size_needed = name_length + t->dirname_length + 2;
	archive_string_ensure(&t->path, size_needed);
	/* Add a separating '/' if it's needed. */
	if (t->dirname_length > 0 && t->path.s[archive_strlen(&t->path)-1] != '/')
		archive_strappend_char(&t->path, '/');
	t->basename = t->path.s + archive_strlen(&t->path);
	archive_strncat(&t->path, name, name_length);
	t->restore_time.name = t->basename;
}

/*
 * Open a directory tree for traversal.
 */
static struct tree *
tree_open(const char *path, int symlink_mode, int restore_time)
{
	struct tree *t;

	if ((t = calloc(1, sizeof(*t))) == NULL)
		return (NULL);
	archive_string_init(&t->path);
	archive_string_ensure(&t->path, 31);
	t->initial_symlink_mode = symlink_mode;
	return (tree_reopen(t, path, restore_time));
}

static struct tree *
tree_reopen(struct tree *t, const char *path, int restore_time)
{
	t->flags = (restore_time)?needsRestoreTimes:0;
	t->flags |= onInitialDir;
	t->visit_type = 0;
	t->tree_errno = 0;
	t->dirname_length = 0;
	t->depth = 0;
	t->descend = 0;
	t->current = NULL;
	t->d = INVALID_DIR_HANDLE;
	t->symlink_mode = t->initial_symlink_mode;
	archive_string_empty(&t->path);
	t->entry_fd = -1;
	t->entry_eof = 0;
	t->entry_remaining_bytes = 0;
	t->initial_filesystem_id = -1;

	/* First item is set up a lot like a symlink traversal. */
	tree_push(t, path, 0, 0, 0, NULL);
	t->stack->flags = needsFirstVisit;
	t->maxOpenCount = t->openCount = 1;
	t->initial_dir_fd = open(".", O_RDONLY | O_CLOEXEC);
	__archive_ensure_cloexec_flag(t->initial_dir_fd);
	t->working_dir_fd = tree_dup(t->initial_dir_fd);
	return (t);
}

static int
tree_descent(struct tree *t)
{
	int flag, new_fd, r = 0;

	t->dirname_length = archive_strlen(&t->path);
	flag = O_RDONLY | O_CLOEXEC;
#if defined(O_DIRECTORY)
	flag |= O_DIRECTORY;
#endif
	new_fd = open_on_current_dir(t, t->stack->name.s, flag);
	__archive_ensure_cloexec_flag(new_fd);
	if (new_fd < 0) {
		t->tree_errno = errno;
		r = TREE_ERROR_DIR;
	} else {
		t->depth++;
		/* If it is a link, set up fd for the ascent. */
		if (t->stack->flags & isDirLink) {
			t->stack->symlink_parent_fd = t->working_dir_fd;
			t->openCount++;
			if (t->openCount > t->maxOpenCount)
				t->maxOpenCount = t->openCount;
		} else
			close(t->working_dir_fd);
		/* Renew the current working directory. */
		t->working_dir_fd = new_fd;
		t->flags &= ~onWorkingDir;
	}
	return (r);
}

/*
 * We've finished a directory; ascend back to the parent.
 */
static int
tree_ascend(struct tree *t)
{
	struct tree_entry *te;
	int new_fd, r = 0, prev_dir_fd;

	te = t->stack;
	prev_dir_fd = t->working_dir_fd;
	if (te->flags & isDirLink)
		new_fd = te->symlink_parent_fd;
	else {
		new_fd = open_on_current_dir(t, "..", O_RDONLY | O_CLOEXEC);
		__archive_ensure_cloexec_flag(new_fd);
	}
	if (new_fd < 0) {
		t->tree_errno = errno;
		r = TREE_ERROR_FATAL;
	} else {
		/* Renew the current working directory. */
		t->working_dir_fd = new_fd;
		t->flags &= ~onWorkingDir;
		/* Current directory has been changed, we should
		 * close an fd of previous working directory. */
		close_and_restore_time(prev_dir_fd, t, &te->restore_time);
		if (te->flags & isDirLink) {
			t->openCount--;
			te->symlink_parent_fd = -1;
		}
		t->depth--;
	}
	return (r);
}

/*
 * Return to the initial directory where tree_open() was performed.
 */
static int
tree_enter_initial_dir(struct tree *t)
{
	int r = 0;

	if ((t->flags & onInitialDir) == 0) {
		r = fchdir(t->initial_dir_fd);
		if (r == 0) {
			t->flags &= ~onWorkingDir;
			t->flags |= onInitialDir;
		}
	}
	return (r);
}

/*
 * Restore working directory of directory traversals.
 */
static int
tree_enter_working_dir(struct tree *t)
{
	int r = 0;

	/*
	 * Change the current directory if really needed.
	 * Sometimes this is unneeded when we did not do
	 * descent.
	 */
	if (t->depth > 0 && (t->flags & onWorkingDir) == 0) {
		r = fchdir(t->working_dir_fd);
		if (r == 0) {
			t->flags &= ~onInitialDir;
			t->flags |= onWorkingDir;
		}
	}
	return (r);
}

static int
tree_current_dir_fd(struct tree *t)
{
	return (t->working_dir_fd);
}

/*
 * Pop the working stack.
 */
static void
tree_pop(struct tree *t)
{
	struct tree_entry *te;

	t->path.s[t->dirname_length] = '\0';
	t->path.length = t->dirname_length;
	if (t->stack == t->current && t->current != NULL)
		t->current = t->current->parent;
	te = t->stack;
	t->stack = te->next;
	t->dirname_length = te->dirname_length;
	t->basename = t->path.s + t->dirname_length;
	while (t->basename[0] == '/')
		t->basename++;
	archive_string_free(&te->name);
	free(te);
}

/*
 * Get the next item in the tree traversal.
 */
static int
tree_next(struct tree *t)
{
	int r;

	while (t->stack != NULL) {
		/* If there's an open dir, get the next entry from there. */
		if (t->d != INVALID_DIR_HANDLE) {
			r = tree_dir_next_posix(t);
			if (r == 0)
				continue;
			return (r);
		}

		if (t->stack->flags & needsFirstVisit) {
			/* Top stack item needs a regular visit. */
			t->current = t->stack;
			tree_append(t, t->stack->name.s,
			    archive_strlen(&(t->stack->name)));
			/* t->dirname_length = t->path_length; */
			/* tree_pop(t); */
			t->stack->flags &= ~needsFirstVisit;
			return (t->visit_type = TREE_REGULAR);
		} else if (t->stack->flags & needsDescent) {
			/* Top stack item is dir to descend into. */
			t->current = t->stack;
			tree_append(t, t->stack->name.s,
			    archive_strlen(&(t->stack->name)));
			t->stack->flags &= ~needsDescent;
			r = tree_descent(t);
			if (r != 0) {
				tree_pop(t);
				t->visit_type = r;
			} else
				t->visit_type = TREE_POSTDESCENT;
			return (t->visit_type);
		} else if (t->stack->flags & needsOpen) {
			t->stack->flags &= ~needsOpen;
			r = tree_dir_next_posix(t);
			if (r == 0)
				continue;
			return (r);
		} else if (t->stack->flags & needsAscent) {
		        /* Top stack item is dir and we're done with it. */
			r = tree_ascend(t);
			tree_pop(t);
			t->visit_type = r != 0 ? r : TREE_POSTASCENT;
			return (t->visit_type);
		} else {
			/* Top item on stack is dead. */
			tree_pop(t);
			t->flags &= ~hasLstat;
			t->flags &= ~hasStat;
		}
	}
	return (t->visit_type = 0);
}

static int
tree_dir_next_posix(struct tree *t)
{
	int r;
	const char *name;
	size_t namelen;

	if (t->d == NULL) {
#if defined(USE_READDIR_R)
		size_t dirent_size;
#endif

#if defined(HAVE_FDOPENDIR)
		t->d = fdopendir(tree_dup(t->working_dir_fd));
#else /* HAVE_FDOPENDIR */
		if (tree_enter_working_dir(t) == 0) {
			t->d = opendir(".");
#if HAVE_DIRFD || defined(dirfd)
			__archive_ensure_cloexec_flag(dirfd(t->d));
#endif
		}
#endif /* HAVE_FDOPENDIR */
		if (t->d == NULL) {
			r = tree_ascend(t); /* Undo "chdir" */
			tree_pop(t);
			t->tree_errno = errno;
			t->visit_type = r != 0 ? r : TREE_ERROR_DIR;
			return (t->visit_type);
		}
#if defined(USE_READDIR_R)
		dirent_size = offsetof(struct dirent, d_name) +
		  t->filesystem_table[t->current->filesystem_id].name_max + 1;
		if (t->dirent == NULL || t->dirent_allocated < dirent_size) {
			free(t->dirent);
			t->dirent = malloc(dirent_size);
			if (t->dirent == NULL) {
				closedir(t->d);
				t->d = INVALID_DIR_HANDLE;
				(void)tree_ascend(t);
				tree_pop(t);
				t->tree_errno = ENOMEM;
				t->visit_type = TREE_ERROR_DIR;
				return (t->visit_type);
			}
			t->dirent_allocated = dirent_size;
		}
#endif /* USE_READDIR_R */
	}
	for (;;) {
		errno = 0;
#if defined(USE_READDIR_R)
		r = readdir_r(t->d, t->dirent, &t->de);
#ifdef _AIX
		/* Note: According to the man page, return value 9 indicates
		 * that the readdir_r was not successful and the error code
		 * is set to the global errno variable. And then if the end
		 * of directory entries was reached, the return value is 9
		 * and the third parameter is set to NULL and errno is
		 * unchanged. */
		if (r == 9)
			r = errno;
#endif /* _AIX */
		if (r != 0 || t->de == NULL) {
#else
		t->de = readdir(t->d);
		if (t->de == NULL) {
			r = errno;
#endif
			closedir(t->d);
			t->d = INVALID_DIR_HANDLE;
			if (r != 0) {
				t->tree_errno = r;
				t->visit_type = TREE_ERROR_DIR;
				return (t->visit_type);
			} else
				return (0);
		}
		name = t->de->d_name;
		namelen = D_NAMELEN(t->de);
		t->flags &= ~hasLstat;
		t->flags &= ~hasStat;
		if (name[0] == '.' && name[1] == '\0')
			continue;
		if (name[0] == '.' && name[1] == '.' && name[2] == '\0')
			continue;
		tree_append(t, name, namelen);
		return (t->visit_type = TREE_REGULAR);
	}
}


/*
 * Get the stat() data for the entry just returned from tree_next().
 */
static const struct stat *
tree_current_stat(struct tree *t)
{
	if (!(t->flags & hasStat)) {
#ifdef HAVE_FSTATAT
		if (fstatat(tree_current_dir_fd(t),
		    tree_current_access_path(t), &t->st, 0) != 0)
#else
		if (tree_enter_working_dir(t) != 0)
			return NULL;
		if (stat(tree_current_access_path(t), &t->st) != 0)
#endif
			return NULL;
		t->flags |= hasStat;
	}
	return (&t->st);
}

/*
 * Get the lstat() data for the entry just returned from tree_next().
 */
static const struct stat *
tree_current_lstat(struct tree *t)
{
	if (!(t->flags & hasLstat)) {
#ifdef HAVE_FSTATAT
		if (fstatat(tree_current_dir_fd(t),
		    tree_current_access_path(t), &t->lst,
		    AT_SYMLINK_NOFOLLOW) != 0)
#else
		if (tree_enter_working_dir(t) != 0)
			return NULL;
		if (lstat(tree_current_access_path(t), &t->lst) != 0)
#endif
			return NULL;
		t->flags |= hasLstat;
	}
	return (&t->lst);
}

/*
 * Test whether current entry is a dir or link to a dir.
 */
static int
tree_current_is_dir(struct tree *t)
{
	const struct stat *st;
	/*
	 * If we already have lstat() info, then try some
	 * cheap tests to determine if this is a dir.
	 */
	if (t->flags & hasLstat) {
		/* If lstat() says it's a dir, it must be a dir. */
		st = tree_current_lstat(t);
		if (st == NULL)
			return 0;
		if (S_ISDIR(st->st_mode))
			return 1;
		/* Not a dir; might be a link to a dir. */
		/* If it's not a link, then it's not a link to a dir. */
		if (!S_ISLNK(st->st_mode))
			return 0;
		/*
		 * It's a link, but we don't know what it's a link to,
		 * so we'll have to use stat().
		 */
	}

	st = tree_current_stat(t);
	/* If we can't stat it, it's not a dir. */
	if (st == NULL)
		return 0;
	/* Use the definitive test.  Hopefully this is cached. */
	return (S_ISDIR(st->st_mode));
}

/*
 * Test whether current entry is a physical directory.  Usually, we
 * already have at least one of stat() or lstat() in memory, so we
 * use tricks to try to avoid an extra trip to the disk.
 */
static int
tree_current_is_physical_dir(struct tree *t)
{
	const struct stat *st;

	/*
	 * If stat() says it isn't a dir, then it's not a dir.
	 * If stat() data is cached, this check is free, so do it first.
	 */
	if (t->flags & hasStat) {
		st = tree_current_stat(t);
		if (st == NULL)
			return (0);
		if (!S_ISDIR(st->st_mode))
			return (0);
	}

	/*
	 * Either stat() said it was a dir (in which case, we have
	 * to determine whether it's really a link to a dir) or
	 * stat() info wasn't available.  So we use lstat(), which
	 * hopefully is already cached.
	 */

	st = tree_current_lstat(t);
	/* If we can't stat it, it's not a dir. */
	if (st == NULL)
		return 0;
	/* Use the definitive test.  Hopefully this is cached. */
	return (S_ISDIR(st->st_mode));
}

/*
 * Test whether the same file has been in the tree as its parent.
 */
static int
tree_target_is_same_as_parent(struct tree *t, const struct stat *st)
{
	struct tree_entry *te;

	for (te = t->current->parent; te != NULL; te = te->parent) {
		if (te->dev == (int64_t)st->st_dev &&
		    te->ino == (int64_t)st->st_ino)
			return (1);
	}
	return (0);
}

/*
 * Test whether the current file is symbolic link target and
 * on the other filesystem.
 */
static int
tree_current_is_symblic_link_target(struct tree *t)
{
	static const struct stat *lst, *st;

	lst = tree_current_lstat(t);
	st = tree_current_stat(t);
	return (st != NULL && lst != NULL &&
	    (int64_t)st->st_dev == t->current_filesystem->dev &&
	    st->st_dev != lst->st_dev);
}

/*
 * Return the access path for the entry just returned from tree_next().
 */
static const char *
tree_current_access_path(struct tree *t)
{
	return (t->basename);
}

/*
 * Return the full path for the entry just returned from tree_next().
 */
static const char *
tree_current_path(struct tree *t)
{
	return (t->path.s);
}

/*
 * Terminate the traversal.
 */
static void
tree_close(struct tree *t)
{

	if (t == NULL)
		return;
	if (t->entry_fd >= 0) {
		close_and_restore_time(t->entry_fd, t, &t->restore_time);
		t->entry_fd = -1;
	}
	/* Close the handle of readdir(). */
	if (t->d != INVALID_DIR_HANDLE) {
		closedir(t->d);
		t->d = INVALID_DIR_HANDLE;
	}
	/* Release anything remaining in the stack. */
	while (t->stack != NULL) {
		if (t->stack->flags & isDirLink)
			close(t->stack->symlink_parent_fd);
		tree_pop(t);
	}
	if (t->working_dir_fd >= 0) {
		close(t->working_dir_fd);
		t->working_dir_fd = -1;
	}
	if (t->initial_dir_fd >= 0) {
		close(t->initial_dir_fd);
		t->initial_dir_fd = -1;
	}
}

/*
 * Release any resources.
 */
static void
tree_free(struct tree *t)
{
	int i;

	if (t == NULL)
		return;
	archive_string_free(&t->path);
#if defined(USE_READDIR_R)
	free(t->dirent);
#endif
	free(t->sparse_list);
	for (i = 0; i < t->max_filesystem_id; i++)
		free(t->filesystem_table[i].allocation_ptr);
	free(t->filesystem_table);
	free(t);
}

#endif