hier.7: Document some recently added directories.

[dragonfly.git] / contrib / 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(HAVE_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(HAVE_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_filesytem;

        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,
                            "Faild : %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, invokng 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,
                            "Faild : %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,
                            "Faild : %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 filesytem ID we've already generated. */
                        t->current_filesystem_id = i;
                        t->current_filesystem = &(t->filesystem_table[i]);
                        return (ARCHIVE_OK);
                }
        }

        /*
         * This is the new filesytem which we have to generate a new ID for.
         */
        fid = t->max_filesystem_id++;
        if (t->max_filesystem_id > t->allocated_filesytem) {
                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_filesytem = 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)
        struct vfsconf vfc;
#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(HAVE_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 /* HAVE_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(HAVE_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(HAVE_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(HAVE_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(HAVE_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 /* HAVE_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__)
        if (rt->mtime == (time_t)-1) {
                timespecs[1].tv_sec = 0;
                timespecs[1].tv_nsec = UTIME_OMIT;
        } else {
                timespecs[1].tv_sec = rt->mtime;
                timespecs[1].tv_nsec = rt->mtime_nsec;
        }

        if (rt->atime == (time_t)-1) {
                timespecs[0].tv_sec = 0;
                timespecs[0].tv_nsec = UTIME_OMIT;
        } else {
                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 = malloc(sizeof(*te));
        memset(te, 0, 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 = malloc(sizeof(*t))) == NULL)
                return (NULL);
        memset(t, 0, sizeof(*t));
        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(HAVE_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(HAVE_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 /* HAVE_READDIR_R */
        }
        for (;;) {
                errno = 0;
#if defined(HAVE_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(HAVE_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