CMake/Utilities/cmlibarchive/libarchive/archive_write_disk.c

/*-
 * Copyright (c) 2003-2007 Tim Kientzle
 * 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.
 */

#include "archive_platform.h"
__FBSDID("$FreeBSD: src/lib/libarchive/archive_write_disk.c,v 1.42 2008/12/06 05:55:46 kientzle Exp $");

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_ACL_H
#include <sys/acl.h>
#endif
#ifdef HAVE_SYS_EXTATTR_H
#include <sys/extattr.h>
#endif
#ifdef HAVE_SYS_XATTR_H
#include <sys/xattr.h>
#endif
#ifdef HAVE_ATTR_XATTR_H
#include <attr/xattr.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_UTIME_H
#include <sys/utime.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_GRP_H
#include <grp.h>
#endif
#ifdef HAVE_LINUX_FS_H
#include <linux/fs.h>   /* for Linux file flags */
#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_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif
#include <stdio.h>
#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_UTIME_H
#include <utime.h>
#endif

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

#ifndef O_BINARY
#define O_BINARY 0
#endif

struct fixup_entry {
    struct fixup_entry  *next;
    mode_t           mode;
    int64_t          atime;
    int64_t                  birthtime;
    int64_t          mtime;
    unsigned long        atime_nanos;
    unsigned long            birthtime_nanos;
    unsigned long        mtime_nanos;
    unsigned long        fflags_set;
    int          fixup; /* bitmask of what needs fixing */
    char            *name;
};

/*
 * We use a bitmask to track which operations remain to be done for
 * this file.  In particular, this helps us avoid unnecessary
 * operations when it's possible to take care of one step as a
 * side-effect of another.  For example, mkdir() can specify the mode
 * for the newly-created object but symlink() cannot.  This means we
 * can skip chmod() if mkdir() succeeded, but we must explicitly
 * chmod() if we're trying to create a directory that already exists
 * (mkdir() failed) or if we're restoring a symlink.  Similarly, we
 * need to verify UID/GID before trying to restore SUID/SGID bits;
 * that verification can occur explicitly through a stat() call or
 * implicitly because of a successful chown() call.
 */
#define TODO_MODE_FORCE     0x40000000
#define TODO_MODE_BASE      0x20000000
#define TODO_SUID       0x10000000
#define TODO_SUID_CHECK     0x08000000
#define TODO_SGID       0x04000000
#define TODO_SGID_CHECK     0x02000000
#define TODO_MODE       (TODO_MODE_BASE|TODO_SUID|TODO_SGID)
#define TODO_TIMES      ARCHIVE_EXTRACT_TIME
#define TODO_OWNER      ARCHIVE_EXTRACT_OWNER
#define TODO_FFLAGS     ARCHIVE_EXTRACT_FFLAGS
#define TODO_ACLS       ARCHIVE_EXTRACT_ACL
#define TODO_XATTR      ARCHIVE_EXTRACT_XATTR

struct archive_write_disk {
    struct archive  archive;

    mode_t           user_umask;
    struct fixup_entry  *fixup_list;
    struct fixup_entry  *current_fixup;
    uid_t            user_uid;
    dev_t            skip_file_dev;
    ino_t            skip_file_ino;
    time_t           start_time;

    gid_t (*lookup_gid)(void *private, const char *gname, gid_t gid);
    void  (*cleanup_gid)(void *private);
    void            *lookup_gid_data;
    uid_t (*lookup_uid)(void *private, const char *gname, gid_t gid);
    void  (*cleanup_uid)(void *private);
    void            *lookup_uid_data;

    /*
     * Full path of last file to satisfy symlink checks.
     */
    struct archive_string   path_safe;

    /*
     * Cached stat data from disk for the current entry.
     * If this is valid, pst points to st.  Otherwise,
     * pst is null.
     */
    struct stat      st;
    struct stat     *pst;

    /* Information about the object being restored right now. */
    struct archive_entry    *entry; /* Entry being extracted. */
    char            *name; /* Name of entry, possibly edited. */
    struct archive_string    _name_data; /* backing store for 'name' */
    /* Tasks remaining for this object. */
    int          todo;
    /* Tasks deferred until end-of-archive. */
    int          deferred;
    /* Options requested by the client. */
    int          flags;
    /* Handle for the file we're restoring. */
    int          fd;
    /* Current offset for writing data to the file. */
    off_t            offset;
    /* Last offset actually written to disk. */
    off_t            fd_offset;
    /* Maximum size of file, -1 if unknown. */
    off_t            filesize;
    /* Dir we were in before this restore; only for deep paths. */
    int          restore_pwd;
    /* Mode we should use for this entry; affected by _PERM and umask. */
    mode_t           mode;
    /* UID/GID to use in restoring this entry. */
    uid_t            uid;
    gid_t            gid;
};

/*
 * Default mode for dirs created automatically (will be modified by umask).
 * Note that POSIX specifies 0777 for implicity-created dirs, "modified
 * by the process' file creation mask."
 */
#define DEFAULT_DIR_MODE 0777
/*
 * Dir modes are restored in two steps:  During the extraction, the permissions
 * in the archive are modified to match the following limits.  During
 * the post-extract fixup pass, the permissions from the archive are
 * applied.
 */
#define MINIMUM_DIR_MODE 0700
#define MAXIMUM_DIR_MODE 0775

static int  check_symlinks(struct archive_write_disk *);
static int  create_filesystem_object(struct archive_write_disk *);
static struct fixup_entry *current_fixup(struct archive_write_disk *, const char *pathname);
#ifdef HAVE_FCHDIR
static void edit_deep_directories(struct archive_write_disk *ad);
#endif
static int  cleanup_pathname(struct archive_write_disk *);
static int  create_dir(struct archive_write_disk *, char *);
static int  create_parent_dir(struct archive_write_disk *, char *);
static int  older(struct stat *, struct archive_entry *);
static int  restore_entry(struct archive_write_disk *);
#ifdef HAVE_POSIX_ACL
static int  set_acl(struct archive_write_disk *, int fd, struct archive_entry *,
            acl_type_t, int archive_entry_acl_type, const char *tn);
#endif
static int  set_acls(struct archive_write_disk *);
static int  set_xattrs(struct archive_write_disk *);
static int  set_fflags(struct archive_write_disk *);
static int  set_fflags_platform(struct archive_write_disk *, int fd,
            const char *name, mode_t mode,
            unsigned long fflags_set, unsigned long fflags_clear);
static int  set_ownership(struct archive_write_disk *);
static int  set_mode(struct archive_write_disk *, int mode);
static int  set_time(int, int, const char *, time_t, long, time_t, long);
static int  set_times(struct archive_write_disk *);
static struct fixup_entry *sort_dir_list(struct fixup_entry *p);
static gid_t    trivial_lookup_gid(void *, const char *, gid_t);
static uid_t    trivial_lookup_uid(void *, const char *, uid_t);
static ssize_t  write_data_block(struct archive_write_disk *,
            const char *, size_t);

static struct archive_vtable *archive_write_disk_vtable(void);

static int  _archive_write_close(struct archive *);
static int  _archive_write_finish(struct archive *);
static int  _archive_write_header(struct archive *, struct archive_entry *);
static int  _archive_write_finish_entry(struct archive *);
static ssize_t  _archive_write_data(struct archive *, const void *, size_t);
static ssize_t  _archive_write_data_block(struct archive *, const void *, size_t, off_t);

static int
_archive_write_disk_lazy_stat(struct archive_write_disk *a)
{
    if (a->pst != NULL) {
        /* Already have stat() data available. */
        return (ARCHIVE_OK);
    }
#ifdef HAVE_FSTAT
    if (a->fd >= 0 && fstat(a->fd, &a->st) == 0) {
        a->pst = &a->st;
        return (ARCHIVE_OK);
    }
#endif
    /*
     * XXX At this point, symlinks should not be hit, otherwise
     * XXX a race occured.  Do we want to check explicitly for that?
     */
    if (lstat(a->name, &a->st) == 0) {
        a->pst = &a->st;
        return (ARCHIVE_OK);
    }
    archive_set_error(&a->archive, errno, "Couldn't stat file");
    return (ARCHIVE_WARN);
}

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

    if (!inited) {
        av.archive_close = _archive_write_close;
        av.archive_finish = _archive_write_finish;
        av.archive_write_header = _archive_write_header;
        av.archive_write_finish_entry = _archive_write_finish_entry;
        av.archive_write_data = _archive_write_data;
        av.archive_write_data_block = _archive_write_data_block;
    }
    return (&av);
}


int
archive_write_disk_set_options(struct archive *_a, int flags)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;

    a->flags = flags;
    return (ARCHIVE_OK);
}


/*
 * Extract this entry to disk.
 *
 * TODO: Validate hardlinks.  According to the standards, we're
 * supposed to check each extracted hardlink and squawk if it refers
 * to a file that we didn't restore.  I'm not entirely convinced this
 * is a good idea, but more importantly: Is there any way to validate
 * hardlinks without keeping a complete list of filenames from the
 * entire archive?? Ugh.
 *
 */
static int
_archive_write_header(struct archive *_a, struct archive_entry *entry)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    struct fixup_entry *fe;
    int ret, r;

    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
        "archive_write_disk_header");
    archive_clear_error(&a->archive);
    if (a->archive.state & ARCHIVE_STATE_DATA) {
        r = _archive_write_finish_entry(&a->archive);
        if (r == ARCHIVE_FATAL)
            return (r);
    }

    /* Set up for this particular entry. */
    a->pst = NULL;
    a->current_fixup = NULL;
    a->deferred = 0;
    if (a->entry) {
        archive_entry_free(a->entry);
        a->entry = NULL;
    }
    a->entry = archive_entry_clone(entry);
    a->fd = -1;
    a->fd_offset = 0;
    a->offset = 0;
    a->uid = a->user_uid;
    a->mode = archive_entry_mode(a->entry);
    if (archive_entry_size_is_set(a->entry))
        a->filesize = archive_entry_size(a->entry);
    else
        a->filesize = -1;
    archive_strcpy(&(a->_name_data), archive_entry_pathname(a->entry));
    a->name = a->_name_data.s;
    archive_clear_error(&a->archive);

    /*
     * Clean up the requested path.  This is necessary for correct
     * dir restores; the dir restore logic otherwise gets messed
     * up by nonsense like "dir/.".
     */
    ret = cleanup_pathname(a);
    if (ret != ARCHIVE_OK)
        return (ret);

    /*
     * Set the umask to zero so we get predictable mode settings.
     * This gets done on every call to _write_header in case the
     * user edits their umask during the extraction for some
     * reason. This will be reset before we return.  Note that we
     * don't need to do this in _finish_entry, as the chmod(), etc,
     * system calls don't obey umask.
     */
    a->user_umask = umask(0);
    /* From here on, early exit requires "goto done" to clean up. */

    /* Figure out what we need to do for this entry. */
    a->todo = TODO_MODE_BASE;
    if (a->flags & ARCHIVE_EXTRACT_PERM) {
        a->todo |= TODO_MODE_FORCE; /* Be pushy about permissions. */
        /*
         * SGID requires an extra "check" step because we
         * cannot easily predict the GID that the system will
         * assign.  (Different systems assign GIDs to files
         * based on a variety of criteria, including process
         * credentials and the gid of the enclosing
         * directory.)  We can only restore the SGID bit if
         * the file has the right GID, and we only know the
         * GID if we either set it (see set_ownership) or if
         * we've actually called stat() on the file after it
         * was restored.  Since there are several places at
         * which we might verify the GID, we need a TODO bit
         * to keep track.
         */
        if (a->mode & S_ISGID)
            a->todo |= TODO_SGID | TODO_SGID_CHECK;
        /*
         * Verifying the SUID is simpler, but can still be
         * done in multiple ways, hence the separate "check" bit.
         */
        if (a->mode & S_ISUID)
            a->todo |= TODO_SUID | TODO_SUID_CHECK;
    } else {
        /*
         * User didn't request full permissions, so don't
         * restore SUID, SGID bits and obey umask.
         */
        a->mode &= ~S_ISUID;
        a->mode &= ~S_ISGID;
        a->mode &= ~S_ISVTX;
        a->mode &= ~a->user_umask;
    }
#if !defined(_WIN32) || defined(__CYGWIN__)
    if (a->flags & ARCHIVE_EXTRACT_OWNER)
        a->todo |= TODO_OWNER;
#endif
    if (a->flags & ARCHIVE_EXTRACT_TIME)
        a->todo |= TODO_TIMES;
    if (a->flags & ARCHIVE_EXTRACT_ACL)
        a->todo |= TODO_ACLS;
    if (a->flags & ARCHIVE_EXTRACT_XATTR)
        a->todo |= TODO_XATTR;
    if (a->flags & ARCHIVE_EXTRACT_FFLAGS)
        a->todo |= TODO_FFLAGS;
    if (a->flags & ARCHIVE_EXTRACT_SECURE_SYMLINKS) {
        ret = check_symlinks(a);
        if (ret != ARCHIVE_OK)
            goto done;
    }
#ifdef HAVE_FCHDIR
    /* If path exceeds PATH_MAX, shorten the path. */
    edit_deep_directories(a);
#endif

    ret = restore_entry(a);

    /*
     * On the GNU tar mailing list, some people working with new
     * Linux filesystems observed that system xattrs used as
     * layout hints need to be restored before the file contents
     * are written, so this can't be done at file close.
     */
    if (a->todo & TODO_XATTR) {
        int r2 = set_xattrs(a);
        if (r2 < ret) ret = r2;
    }

#ifdef HAVE_FCHDIR
    /* If we changed directory above, restore it here. */
    if (a->restore_pwd >= 0) {
        r = fchdir(a->restore_pwd);
        if (r != 0) {
            archive_set_error(&a->archive, errno, "chdir() failure");
            ret = ARCHIVE_FATAL;
        }
        close(a->restore_pwd);
        a->restore_pwd = -1;
    }
#endif

    /*
     * Fixup uses the unedited pathname from archive_entry_pathname(),
     * because it is relative to the base dir and the edited path
     * might be relative to some intermediate dir as a result of the
     * deep restore logic.
     */
    if (a->deferred & TODO_MODE) {
        fe = current_fixup(a, archive_entry_pathname(entry));
        fe->fixup |= TODO_MODE_BASE;
        fe->mode = a->mode;
    }

    if ((a->deferred & TODO_TIMES)
        && (archive_entry_mtime_is_set(entry)
            || archive_entry_atime_is_set(entry))) {
        fe = current_fixup(a, archive_entry_pathname(entry));
        fe->fixup |= TODO_TIMES;
        if (archive_entry_atime_is_set(entry)) {
            fe->atime = archive_entry_atime(entry);
            fe->atime_nanos = archive_entry_atime_nsec(entry);
        } else {
            /* If atime is unset, use start time. */
            fe->atime = a->start_time;
            fe->atime_nanos = 0;
        }
        if (archive_entry_mtime_is_set(entry)) {
            fe->mtime = archive_entry_mtime(entry);
            fe->mtime_nanos = archive_entry_mtime_nsec(entry);
        } else {
            /* If mtime is unset, use start time. */
            fe->mtime = a->start_time;
            fe->mtime_nanos = 0;
        }
        if (archive_entry_birthtime_is_set(entry)) {
            fe->birthtime = archive_entry_birthtime(entry);
            fe->birthtime_nanos = archive_entry_birthtime_nsec(entry);
        } else {
            /* If birthtime is unset, use mtime. */
            fe->birthtime = fe->mtime;
            fe->birthtime_nanos = fe->mtime_nanos;
        }
    }

    if (a->deferred & TODO_FFLAGS) {
        fe = current_fixup(a, archive_entry_pathname(entry));
        fe->fixup |= TODO_FFLAGS;
        /* TODO: Complete this.. defer fflags from below. */
    }

    /* We've created the object and are ready to pour data into it. */
    if (ret >= ARCHIVE_WARN)
        a->archive.state = ARCHIVE_STATE_DATA;
    /*
     * If it's not open, tell our client not to try writing.
     * In particular, dirs, links, etc, don't get written to.
     */
    if (a->fd < 0) {
        archive_entry_set_size(entry, 0);
        a->filesize = 0;
    }
done:
    /* Restore the user's umask before returning. */
    umask(a->user_umask);

    return (ret);
}

int
archive_write_disk_set_skip_file(struct archive *_a, dev_t d, ino_t i)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_ANY, "archive_write_disk_set_skip_file");
    a->skip_file_dev = d;
    a->skip_file_ino = i;
    return (ARCHIVE_OK);
}

static ssize_t
write_data_block(struct archive_write_disk *a, const char *buff, size_t size)
{
    uint64_t start_size = size;
    ssize_t bytes_written = 0;
    ssize_t block_size = 0, bytes_to_write;

    if (size == 0)
        return (ARCHIVE_OK);

    if (a->filesize == 0 || a->fd < 0) {
        archive_set_error(&a->archive, 0,
            "Attempt to write to an empty file");
        return (ARCHIVE_WARN);
    }

    if (a->flags & ARCHIVE_EXTRACT_SPARSE) {
#if HAVE_STRUCT_STAT_ST_BLKSIZE
        int r;
        if ((r = _archive_write_disk_lazy_stat(a)) != ARCHIVE_OK)
            return (r);
        block_size = a->pst->st_blksize;
#else
        /* XXX TODO XXX Is there a more appropriate choice here ? */
        /* This needn't match the filesystem allocation size. */
        block_size = 16*1024;
#endif
    }

    /* If this write would run beyond the file size, truncate it. */
    if (a->filesize >= 0 && (off_t)(a->offset + size) > a->filesize)
        start_size = size = (size_t)(a->filesize - a->offset);

    /* Write the data. */
    while (size > 0) {
        if (block_size == 0) {
            bytes_to_write = size;
        } else {
            /* We're sparsifying the file. */
            const char *p, *end;
            off_t block_end;

            /* Skip leading zero bytes. */
            for (p = buff, end = buff + size; p < end; ++p) {
                if (*p != '\0')
                    break;
            }
            a->offset += p - buff;
            size -= p - buff;
            buff = p;
            if (size == 0)
                break;

            /* Calculate next block boundary after offset. */
            block_end
                = (a->offset / block_size + 1) * block_size;

            /* If the adjusted write would cross block boundary,
             * truncate it to the block boundary. */
            bytes_to_write = size;
            if (a->offset + bytes_to_write > block_end)
                bytes_to_write = block_end - a->offset;
        }
        /* Seek if necessary to the specified offset. */
        if (a->offset != a->fd_offset) {
            if (lseek(a->fd, a->offset, SEEK_SET) < 0) {
                archive_set_error(&a->archive, errno,
                    "Seek failed");
                return (ARCHIVE_FATAL);
            }
            a->fd_offset = a->offset;
            a->archive.file_position = a->offset;
            a->archive.raw_position = a->offset;
        }
        bytes_written = write(a->fd, buff, bytes_to_write);
        if (bytes_written < 0) {
            archive_set_error(&a->archive, errno, "Write failed");
            return (ARCHIVE_WARN);
        }
        buff += bytes_written;
        size -= bytes_written;
        a->offset += bytes_written;
        a->archive.file_position += bytes_written;
        a->archive.raw_position += bytes_written;
        a->fd_offset = a->offset;
    }
    return (start_size - size);
}

static ssize_t
_archive_write_data_block(struct archive *_a,
    const void *buff, size_t size, off_t offset)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    ssize_t r;

    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_DATA, "archive_write_disk_block");

    a->offset = offset;
    r = write_data_block(a, buff, size);
    if (r < ARCHIVE_OK)
        return (r);
    if ((size_t)r < size) {
        archive_set_error(&a->archive, 0,
            "Write request too large");
        return (ARCHIVE_WARN);
    }
    return (ARCHIVE_OK);
}

static ssize_t
_archive_write_data(struct archive *_a, const void *buff, size_t size)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;

    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_DATA, "archive_write_data");

    return (write_data_block(a, buff, size));
}

static int
_archive_write_finish_entry(struct archive *_a)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    int ret = ARCHIVE_OK;

    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
        "archive_write_finish_entry");
    if (a->archive.state & ARCHIVE_STATE_HEADER)
        return (ARCHIVE_OK);
    archive_clear_error(&a->archive);

    /* Pad or truncate file to the right size. */
    if (a->fd < 0) {
        /* There's no file. */
    } else if (a->filesize < 0) {
        /* File size is unknown, so we can't set the size. */
    } else if (a->fd_offset == a->filesize) {
        /* Last write ended at exactly the filesize; we're done. */
        /* Hopefully, this is the common case. */
    } else {
#if HAVE_FTRUNCATE
        if (ftruncate(a->fd, a->filesize) == -1 &&
            a->filesize == 0) {
            archive_set_error(&a->archive, errno,
                "File size could not be restored");
            return (ARCHIVE_FAILED);
        }
#endif
        /*
         * Not all platforms implement the XSI option to
         * extend files via ftruncate.  Stat() the file again
         * to see what happened.
         */
        a->pst = NULL;
        if ((ret = _archive_write_disk_lazy_stat(a)) != ARCHIVE_OK)
            return (ret);
        /* We can use lseek()/write() to extend the file if
         * ftruncate didn't work or isn't available. */
        if (a->st.st_size < a->filesize) {
            const char nul = '\0';
            if (lseek(a->fd, a->filesize - 1, SEEK_SET) < 0) {
                archive_set_error(&a->archive, errno,
                    "Seek failed");
                return (ARCHIVE_FATAL);
            }
            if (write(a->fd, &nul, 1) < 0) {
                archive_set_error(&a->archive, errno,
                    "Write to restore size failed");
                return (ARCHIVE_FATAL);
            }
            a->pst = NULL;
        }
    }

    /* Restore metadata. */

    /*
     * Look up the "real" UID only if we're going to need it.
     * TODO: the TODO_SGID condition can be dropped here, can't it?
     */
    if (a->todo & (TODO_OWNER | TODO_SUID | TODO_SGID)) {
        a->uid = a->lookup_uid(a->lookup_uid_data,
            archive_entry_uname(a->entry),
            archive_entry_uid(a->entry));
    }
    /* Look up the "real" GID only if we're going to need it. */
    /* TODO: the TODO_SUID condition can be dropped here, can't it? */
    if (a->todo & (TODO_OWNER | TODO_SGID | TODO_SUID)) {
        a->gid = a->lookup_gid(a->lookup_gid_data,
            archive_entry_gname(a->entry),
            archive_entry_gid(a->entry));
     }
    /*
     * If restoring ownership, do it before trying to restore suid/sgid
     * bits.  If we set the owner, we know what it is and can skip
     * a stat() call to examine the ownership of the file on disk.
     */
    if (a->todo & TODO_OWNER)
        ret = set_ownership(a);
    if (a->todo & TODO_MODE) {
        int r2 = set_mode(a, a->mode);
        if (r2 < ret) ret = r2;
    }
    if (a->todo & TODO_ACLS) {
        int r2 = set_acls(a);
        if (r2 < ret) ret = r2;
    }
    /*
     * Some flags prevent file modification; they must be restored after
     * file contents are written.
     */
    if (a->todo & TODO_FFLAGS) {
        int r2 = set_fflags(a);
        if (r2 < ret) ret = r2;
    }
    /*
     * Time has to be restored after all other metadata;
     * otherwise atime will get changed.
     */
    if (a->todo & TODO_TIMES) {
        int r2 = set_times(a);
        if (r2 < ret) ret = r2;
    }

    /* If there's an fd, we can close it now. */
    if (a->fd >= 0) {
        close(a->fd);
        a->fd = -1;
    }
    /* If there's an entry, we can release it now. */
    if (a->entry) {
        archive_entry_free(a->entry);
        a->entry = NULL;
    }
    a->archive.state = ARCHIVE_STATE_HEADER;
    return (ret);
}

int
archive_write_disk_set_group_lookup(struct archive *_a,
    void *private_data,
    gid_t (*lookup_gid)(void *private, const char *gname, gid_t gid),
    void (*cleanup_gid)(void *private))
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_ANY, "archive_write_disk_set_group_lookup");

    a->lookup_gid = lookup_gid;
    a->cleanup_gid = cleanup_gid;
    a->lookup_gid_data = private_data;
    return (ARCHIVE_OK);
}

int
archive_write_disk_set_user_lookup(struct archive *_a,
    void *private_data,
    uid_t (*lookup_uid)(void *private, const char *uname, uid_t uid),
    void (*cleanup_uid)(void *private))
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_ANY, "archive_write_disk_set_user_lookup");

    a->lookup_uid = lookup_uid;
    a->cleanup_uid = cleanup_uid;
    a->lookup_uid_data = private_data;
    return (ARCHIVE_OK);
}


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

    a = (struct archive_write_disk *)malloc(sizeof(*a));
    if (a == NULL)
        return (NULL);
    memset(a, 0, sizeof(*a));
    a->archive.magic = ARCHIVE_WRITE_DISK_MAGIC;
    /* We're ready to write a header immediately. */
    a->archive.state = ARCHIVE_STATE_HEADER;
    a->archive.vtable = archive_write_disk_vtable();
    a->lookup_uid = trivial_lookup_uid;
    a->lookup_gid = trivial_lookup_gid;
    a->start_time = time(NULL);
#ifdef HAVE_GETEUID
    a->user_uid = geteuid();
#endif /* HAVE_GETEUID */
    if (archive_string_ensure(&a->path_safe, 512) == NULL) {
        free(a);
        return (NULL);
    }
    return (&a->archive);
}


/*
 * If pathname is longer than PATH_MAX, chdir to a suitable
 * intermediate dir and edit the path down to a shorter suffix.  Note
 * that this routine never returns an error; if the chdir() attempt
 * fails for any reason, we just go ahead with the long pathname.  The
 * object creation is likely to fail, but any error will get handled
 * at that time.
 */
#ifdef HAVE_FCHDIR
static void
edit_deep_directories(struct archive_write_disk *a)
{
    int ret;
    char *tail = a->name;

    a->restore_pwd = -1;

    /* If path is short, avoid the open() below. */
    if (strlen(tail) <= PATH_MAX)
        return;

    /* Try to record our starting dir. */
    a->restore_pwd = open(".", O_RDONLY | O_BINARY);
    if (a->restore_pwd < 0)
        return;

    /* As long as the path is too long... */
    while (strlen(tail) > PATH_MAX) {
        /* Locate a dir prefix shorter than PATH_MAX. */
        tail += PATH_MAX - 8;
        while (tail > a->name && *tail != '/')
            tail--;
        /* Exit if we find a too-long path component. */
        if (tail <= a->name)
            return;
        /* Create the intermediate dir and chdir to it. */
        *tail = '\0'; /* Terminate dir portion */
        ret = create_dir(a, a->name);
        if (ret == ARCHIVE_OK && chdir(a->name) != 0)
            ret = ARCHIVE_FAILED;
        *tail = '/'; /* Restore the / we removed. */
        if (ret != ARCHIVE_OK)
            return;
        tail++;
        /* The chdir() succeeded; we've now shortened the path. */
        a->name = tail;
    }
    return;
}
#endif

/*
 * The main restore function.
 */
static int
restore_entry(struct archive_write_disk *a)
{
    int ret = ARCHIVE_OK, en;

    if (a->flags & ARCHIVE_EXTRACT_UNLINK && !S_ISDIR(a->mode)) {
        /*
         * TODO: Fix this.  Apparently, there are platforms
         * that still allow root to hose the entire filesystem
         * by unlinking a dir.  The S_ISDIR() test above
         * prevents us from using unlink() here if the new
         * object is a dir, but that doesn't mean the old
         * object isn't a dir.
         */
        if (unlink(a->name) == 0) {
            /* We removed it, reset cached stat. */
            a->pst = NULL;
        } else if (errno == ENOENT) {
            /* File didn't exist, that's just as good. */
        } else if (rmdir(a->name) == 0) {
            /* It was a dir, but now it's gone. */
            a->pst = NULL;
        } else {
            /* We tried, but couldn't get rid of it. */
            archive_set_error(&a->archive, errno,
                "Could not unlink");
            return(ARCHIVE_FAILED);
        }
    }

    /* Try creating it first; if this fails, we'll try to recover. */
    en = create_filesystem_object(a);

    if ((en == ENOTDIR || en == ENOENT)
        && !(a->flags & ARCHIVE_EXTRACT_NO_AUTODIR)) {
        /* If the parent dir doesn't exist, try creating it. */
        create_parent_dir(a, a->name);
        /* Now try to create the object again. */
        en = create_filesystem_object(a);
    }

    if ((en == EISDIR || en == EEXIST)
        && (a->flags & ARCHIVE_EXTRACT_NO_OVERWRITE)) {
        /* If we're not overwriting, we're done. */
        archive_set_error(&a->archive, en, "Already exists");
        return (ARCHIVE_FAILED);
    }

    /*
     * Some platforms return EISDIR if you call
     * open(O_WRONLY | O_EXCL | O_CREAT) on a directory, some
     * return EEXIST.  POSIX is ambiguous, requiring EISDIR
     * for open(O_WRONLY) on a dir and EEXIST for open(O_EXCL | O_CREAT)
     * on an existing item.
     */
    if (en == EISDIR) {
        /* A dir is in the way of a non-dir, rmdir it. */
        if (rmdir(a->name) != 0) {
            archive_set_error(&a->archive, errno,
                "Can't remove already-existing dir");
            return (ARCHIVE_FAILED);
        }
        a->pst = NULL;
        /* Try again. */
        en = create_filesystem_object(a);
    } else if (en == EEXIST) {
        /*
         * We know something is in the way, but we don't know what;
         * we need to find out before we go any further.
         */
        int r = 0;
        /*
         * The SECURE_SYMLINK logic has already removed a
         * symlink to a dir if the client wants that.  So
         * follow the symlink if we're creating a dir.
         */
        if (S_ISDIR(a->mode))
            r = stat(a->name, &a->st);
        /*
         * If it's not a dir (or it's a broken symlink),
         * then don't follow it.
         */
        if (r != 0 || !S_ISDIR(a->mode))
            r = lstat(a->name, &a->st);
        if (r != 0) {
            archive_set_error(&a->archive, errno,
                "Can't stat existing object");
            return (ARCHIVE_FAILED);
        }

        /*
         * NO_OVERWRITE_NEWER doesn't apply to directories.
         */
        if ((a->flags & ARCHIVE_EXTRACT_NO_OVERWRITE_NEWER)
            &&  !S_ISDIR(a->st.st_mode)) {
            if (!older(&(a->st), a->entry)) {
                archive_set_error(&a->archive, 0,
                    "File on disk is not older; skipping.");
                return (ARCHIVE_FAILED);
            }
        }

        /* If it's our archive, we're done. */
        if (a->skip_file_dev > 0 &&
            a->skip_file_ino > 0 &&
            a->st.st_dev == a->skip_file_dev &&
            a->st.st_ino == a->skip_file_ino) {
            archive_set_error(&a->archive, 0, "Refusing to overwrite archive");
            return (ARCHIVE_FAILED);
        }

        if (!S_ISDIR(a->st.st_mode)) {
            /* A non-dir is in the way, unlink it. */
            if (unlink(a->name) != 0) {
                archive_set_error(&a->archive, errno,
                    "Can't unlink already-existing object");
                return (ARCHIVE_FAILED);
            }
            a->pst = NULL;
            /* Try again. */
            en = create_filesystem_object(a);
        } else if (!S_ISDIR(a->mode)) {
            /* A dir is in the way of a non-dir, rmdir it. */
            if (rmdir(a->name) != 0) {
                archive_set_error(&a->archive, errno,
                    "Can't remove already-existing dir");
                return (ARCHIVE_FAILED);
            }
            /* Try again. */
            en = create_filesystem_object(a);
        } else {
            /*
             * There's a dir in the way of a dir.  Don't
             * waste time with rmdir()/mkdir(), just fix
             * up the permissions on the existing dir.
             * Note that we don't change perms on existing
             * dirs unless _EXTRACT_PERM is specified.
             */
            if ((a->mode != a->st.st_mode)
                && (a->todo & TODO_MODE_FORCE))
                a->deferred |= (a->todo & TODO_MODE);
            /* Ownership doesn't need deferred fixup. */
            en = 0; /* Forget the EEXIST. */
        }
    }

    if (en) {
        /* Everything failed; give up here. */
        archive_set_error(&a->archive, en, "Can't create '%s'",
            a->name);
        return (ARCHIVE_FAILED);
    }

    a->pst = NULL; /* Cached stat data no longer valid. */
    return (ret);
}

/*
 * Returns 0 if creation succeeds, or else returns errno value from
 * the failed system call.   Note:  This function should only ever perform
 * a single system call.
 */
static int
create_filesystem_object(struct archive_write_disk *a)
{
    /* Create the entry. */
    const char *linkname;
    mode_t final_mode, mode;
    int r;

    /* We identify hard/symlinks according to the link names. */
    /* Since link(2) and symlink(2) don't handle modes, we're done here. */
    linkname = archive_entry_hardlink(a->entry);
    if (linkname != NULL) {
#if !HAVE_LINK
        return (EPERM);
#else
        r = link(linkname, a->name) ? errno : 0;
        /*
         * New cpio and pax formats allow hardlink entries
         * to carry data, so we may have to open the file
         * for hardlink entries.
         *
         * If the hardlink was successfully created and
         * the archive doesn't have carry data for it,
         * consider it to be non-authoritive for meta data.
         * This is consistent with GNU tar and BSD pax.
         * If the hardlink does carry data, let the last
         * archive entry decide ownership.
         */
        if (r == 0 && a->filesize <= 0) {
            a->todo = 0;
            a->deferred = 0;
        } if (r == 0 && a->filesize > 0) {
            a->fd = open(a->name, O_WRONLY | O_TRUNC | O_BINARY);
            if (a->fd < 0)
                r = errno;
        }
        return (r);
#endif
    }
    linkname = archive_entry_symlink(a->entry);
    if (linkname != NULL) {
#if HAVE_SYMLINK
        return symlink(linkname, a->name) ? errno : 0;
#else
        return (EPERM);
#endif
    }

    /*
     * The remaining system calls all set permissions, so let's
     * try to take advantage of that to avoid an extra chmod()
     * call.  (Recall that umask is set to zero right now!)
     */

    /* Mode we want for the final restored object (w/o file type bits). */
    final_mode = a->mode & 07777;
    /*
     * The mode that will actually be restored in this step.  Note
     * that SUID, SGID, etc, require additional work to ensure
     * security, so we never restore them at this point.
     */
    mode = final_mode & 0777;

    switch (a->mode & AE_IFMT) {
    default:
        /* POSIX requires that we fall through here. */
        /* FALLTHROUGH */
    case AE_IFREG:
        a->fd = open(a->name,
            O_WRONLY | O_CREAT | O_EXCL | O_BINARY, mode);
        r = (a->fd < 0);
        break;
    case AE_IFCHR:
#ifdef HAVE_MKNOD
        /* Note: we use AE_IFCHR for the case label, and
         * S_IFCHR for the mknod() call.  This is correct.  */
        r = mknod(a->name, mode | S_IFCHR,
            archive_entry_rdev(a->entry));
#else
        /* TODO: Find a better way to warn about our inability
         * to restore a char device node. */
        return (EINVAL);
#endif /* HAVE_MKNOD */
        break;
    case AE_IFBLK:
#ifdef HAVE_MKNOD
        r = mknod(a->name, mode | S_IFBLK,
            archive_entry_rdev(a->entry));
#else
        /* TODO: Find a better way to warn about our inability
         * to restore a block device node. */
        return (EINVAL);
#endif /* HAVE_MKNOD */
        break;
    case AE_IFDIR:
        mode = (mode | MINIMUM_DIR_MODE) & MAXIMUM_DIR_MODE;
        r = mkdir(a->name, mode);
        if (r == 0) {
            /* Defer setting dir times. */
            a->deferred |= (a->todo & TODO_TIMES);
            a->todo &= ~TODO_TIMES;
            /* Never use an immediate chmod(). */
            /* We can't avoid the chmod() entirely if EXTRACT_PERM
             * because of SysV SGID inheritance. */
            if ((mode != final_mode)
                || (a->flags & ARCHIVE_EXTRACT_PERM))
                a->deferred |= (a->todo & TODO_MODE);
            a->todo &= ~TODO_MODE;
        }
        break;
    case AE_IFIFO:
#ifdef HAVE_MKFIFO
        r = mkfifo(a->name, mode);
#else
        /* TODO: Find a better way to warn about our inability
         * to restore a fifo. */
        return (EINVAL);
#endif /* HAVE_MKFIFO */
        break;
    }

    /* All the system calls above set errno on failure. */
    if (r)
        return (errno);

    /* If we managed to set the final mode, we've avoided a chmod(). */
    if (mode == final_mode)
        a->todo &= ~TODO_MODE;
    return (0);
}

/*
 * Cleanup function for archive_extract.  Mostly, this involves processing
 * the fixup list, which is used to address a number of problems:
 *   * Dir permissions might prevent us from restoring a file in that
 *     dir, so we restore the dir with minimum 0700 permissions first,
 *     then correct the mode at the end.
 *   * Similarly, the act of restoring a file touches the directory
 *     and changes the timestamp on the dir, so we have to touch-up dir
 *     timestamps at the end as well.
 *   * Some file flags can interfere with the restore by, for example,
 *     preventing the creation of hardlinks to those files.
 *
 * Note that tar/cpio do not require that archives be in a particular
 * order; there is no way to know when the last file has been restored
 * within a directory, so there's no way to optimize the memory usage
 * here by fixing up the directory any earlier than the
 * end-of-archive.
 *
 * XXX TODO: Directory ACLs should be restored here, for the same
 * reason we set directory perms here. XXX
 */
static int
_archive_write_close(struct archive *_a)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    struct fixup_entry *next, *p;
    int ret;

    __archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
        ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
        "archive_write_disk_close");
    ret = _archive_write_finish_entry(&a->archive);

    /* Sort dir list so directories are fixed up in depth-first order. */
    p = sort_dir_list(a->fixup_list);

    while (p != NULL) {
        a->pst = NULL; /* Mark stat cache as out-of-date. */
        if (p->fixup & TODO_TIMES) {
#ifdef HAVE_UTIMES
            /* {f,l,}utimes() are preferred, when available. */
#if defined(_WIN32) && !defined(__CYGWIN__)
            struct __timeval times[2];
#else
            struct timeval times[2];
#endif
            times[0].tv_sec = p->atime;
            times[0].tv_usec = p->atime_nanos / 1000;
#ifdef HAVE_STRUCT_STAT_ST_BIRTHTIME
            /* if it's valid and not mtime, push the birthtime first */
            if (((times[1].tv_sec = p->birthtime) < p->mtime) &&
            (p->birthtime > 0))
            {
                times[1].tv_usec = p->birthtime_nanos / 1000;
                utimes(p->name, times);
            }
#endif
            times[1].tv_sec = p->mtime;
            times[1].tv_usec = p->mtime_nanos / 1000;
#ifdef HAVE_LUTIMES
            lutimes(p->name, times);
#else
            utimes(p->name, times);
#endif
#else
            /* utime() is more portable, but less precise. */
            struct utimbuf times;
            times.modtime = p->mtime;
            times.actime = p->atime;

            utime(p->name, &times);
#endif
        }
        if (p->fixup & TODO_MODE_BASE)
            chmod(p->name, p->mode);

        if (p->fixup & TODO_FFLAGS)
            set_fflags_platform(a, -1, p->name,
                p->mode, p->fflags_set, 0);

        next = p->next;
        free(p->name);
        free(p);
        p = next;
    }
    a->fixup_list = NULL;
    return (ret);
}

static int
_archive_write_finish(struct archive *_a)
{
    struct archive_write_disk *a = (struct archive_write_disk *)_a;
    int ret;
    ret = _archive_write_close(&a->archive);
    if (a->cleanup_gid != NULL && a->lookup_gid_data != NULL)
        (a->cleanup_gid)(a->lookup_gid_data);
    if (a->cleanup_uid != NULL && a->lookup_uid_data != NULL)
        (a->cleanup_uid)(a->lookup_uid_data);
    if (a->entry)
        archive_entry_free(a->entry);
    archive_string_free(&a->_name_data);
    archive_string_free(&a->archive.error_string);
    archive_string_free(&a->path_safe);
    free(a);
    return (ret);
}

/*
 * Simple O(n log n) merge sort to order the fixup list.  In
 * particular, we want to restore dir timestamps depth-first.
 */
static struct fixup_entry *
sort_dir_list(struct fixup_entry *p)
{
    struct fixup_entry *a, *b, *t;

    if (p == NULL)
        return (NULL);
    /* A one-item list is already sorted. */
    if (p->next == NULL)
        return (p);

    /* Step 1: split the list. */
    t = p;
    a = p->next->next;
    while (a != NULL) {
        /* Step a twice, t once. */
        a = a->next;
        if (a != NULL)
            a = a->next;
        t = t->next;
    }
    /* Now, t is at the mid-point, so break the list here. */
    b = t->next;
    t->next = NULL;
    a = p;

    /* Step 2: Recursively sort the two sub-lists. */
    a = sort_dir_list(a);
    b = sort_dir_list(b);

    /* Step 3: Merge the returned lists. */
    /* Pick the first element for the merged list. */
    if (strcmp(a->name, b->name) > 0) {
        t = p = a;
        a = a->next;
    } else {
        t = p = b;
        b = b->next;
    }

    /* Always put the later element on the list first. */
    while (a != NULL && b != NULL) {
        if (strcmp(a->name, b->name) > 0) {
            t->next = a;
            a = a->next;
        } else {
            t->next = b;
            b = b->next;
        }
        t = t->next;
    }

    /* Only one list is non-empty, so just splice it on. */
    if (a != NULL)
        t->next = a;
    if (b != NULL)
        t->next = b;

    return (p);
}

/*
 * Returns a new, initialized fixup entry.
 *
 * TODO: Reduce the memory requirements for this list by using a tree
 * structure rather than a simple list of names.
 */
static struct fixup_entry *
new_fixup(struct archive_write_disk *a, const char *pathname)
{
    struct fixup_entry *fe;

    fe = (struct fixup_entry *)malloc(sizeof(struct fixup_entry));
    if (fe == NULL)
        return (NULL);
    fe->next = a->fixup_list;
    a->fixup_list = fe;
    fe->fixup = 0;
    fe->name = strdup(pathname);
    return (fe);
}

/*
 * Returns a fixup structure for the current entry.
 */
static struct fixup_entry *
current_fixup(struct archive_write_disk *a, const char *pathname)
{
    if (a->current_fixup == NULL)
        a->current_fixup = new_fixup(a, pathname);
    return (a->current_fixup);
}

/* TODO: Make this work. */
/*
 * TODO: The deep-directory support bypasses this; disable deep directory
 * support if we're doing symlink checks.
 */
/*
 * TODO: Someday, integrate this with the deep dir support; they both
 * scan the path and both can be optimized by comparing against other
 * recent paths.
 */
/* TODO: Extend this to support symlinks on Windows Vista and later. */
static int
check_symlinks(struct archive_write_disk *a)
{
#if !defined(HAVE_LSTAT)
    /* Platform doesn't have lstat, so we can't look for symlinks. */
    (void)a; /* UNUSED */
    return (ARCHIVE_OK);
#else
    char *pn, *p;
    char c;
    int r;
    struct stat st;

    /*
     * Guard against symlink tricks.  Reject any archive entry whose
     * destination would be altered by a symlink.
     */
    /* Whatever we checked last time doesn't need to be re-checked. */
    pn = a->name;
    p = a->path_safe.s;
    while ((*pn != '\0') && (*p == *pn))
        ++p, ++pn;
    c = pn[0];
    /* Keep going until we've checked the entire name. */
    while (pn[0] != '\0' && (pn[0] != '/' || pn[1] != '\0')) {
        /* Skip the next path element. */
        while (*pn != '\0' && *pn != '/')
            ++pn;
        c = pn[0];
        pn[0] = '\0';
        /* Check that we haven't hit a symlink. */
        r = lstat(a->name, &st);
        if (r != 0) {
            /* We've hit a dir that doesn't exist; stop now. */
            if (errno == ENOENT)
                break;
        } else if (S_ISLNK(st.st_mode)) {
            if (c == '\0') {
                /*
                 * Last element is symlink; remove it
                 * so we can overwrite it with the
                 * item being extracted.
                 */
                if (unlink(a->name)) {
                    archive_set_error(&a->archive, errno,
                        "Could not remove symlink %s",
                        a->name);
                    pn[0] = c;
                    return (ARCHIVE_FAILED);
                }
                a->pst = NULL;
                /*
                 * Even if we did remove it, a warning
                 * is in order.  The warning is silly,
                 * though, if we're just replacing one
                 * symlink with another symlink.
                 */
                if (!S_ISLNK(a->mode)) {
                    archive_set_error(&a->archive, 0,
                        "Removing symlink %s",
                        a->name);
                }
                /* Symlink gone.  No more problem! */
                pn[0] = c;
                return (0);
            } else if (a->flags & ARCHIVE_EXTRACT_UNLINK) {
                /* User asked us to remove problems. */
                if (unlink(a->name) != 0) {
                    archive_set_error(&a->archive, 0,
                        "Cannot remove intervening symlink %s",
                        a->name);
                    pn[0] = c;
                    return (ARCHIVE_FAILED);
                }
                a->pst = NULL;
            } else {
                archive_set_error(&a->archive, 0,
                    "Cannot extract through symlink %s",
                    a->name);
                pn[0] = c;
                return (ARCHIVE_FAILED);
            }
        }
    }
    pn[0] = c;
    /* We've checked and/or cleaned the whole path, so remember it. */
    archive_strcpy(&a->path_safe, a->name);
    return (ARCHIVE_OK);
#endif
}

#if defined(_WIN32) || defined(__CYGWIN__)
/*
 * 1. Convert a path separator from '\' to '/' .
 *    We shouldn't check multi-byte character directly because some
 *    character-set have been using the '\' character for a part of
 *    its multibyte character code.
 * 2. Replace unusable characters in Windows with underscore('_').
 * See also : http://msdn.microsoft.com/en-us/library/aa365247.aspx
 */
static void
cleanup_pathname_win(struct archive_write_disk *a)
{
    wchar_t wc;
    char *p;
    size_t alen, l;

    alen = 0;
    l = 0;
    for (p = a->name; *p != '\0'; p++) {
        ++alen;
        if (*p == '\\')
            l = 1;
        /* Rewrite the path name if its character is a unusable. */
        if (*p == ':' || *p == '*' || *p == '?' || *p == '"' ||
            *p == '<' || *p == '>' || *p == '|')
            *p = '_';
    }
    if (alen == 0 || l == 0)
        return;
    /*
     * Convert path separator.
     */
    p = a->name;
    while (*p != '\0' && alen) {
        l = mbtowc(&wc, p, alen);
        if (l == -1) {
            while (*p != '\0') {
                if (*p == '\\')
                    *p = '/';
                ++p;
            }
            break;
        }
        if (l == 1 && wc == L'\\')
            *p = '/';
        p += l;
        alen -= l;
    }
}
#endif

/*
 * Canonicalize the pathname.  In particular, this strips duplicate
 * '/' characters, '.' elements, and trailing '/'.  It also raises an
 * error for an empty path, a trailing '..' or (if _SECURE_NODOTDOT is
 * set) any '..' in the path.
 */
static int
cleanup_pathname(struct archive_write_disk *a)
{
    char *dest, *src;
    char separator = '\0';

    dest = src = a->name;
    if (*src == '\0') {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
            "Invalid empty pathname");
        return (ARCHIVE_FAILED);
    }

#if defined(_WIN32) || defined(__CYGWIN__)
    cleanup_pathname_win(a);
#endif
    /* Skip leading '/'. */
    if (*src == '/')
        separator = *src++;

    /* Scan the pathname one element at a time. */
    for (;;) {
        /* src points to first char after '/' */
        if (src[0] == '\0') {
            break;
        } else if (src[0] == '/') {
            /* Found '//', ignore second one. */
            src++;
            continue;
        } else if (src[0] == '.') {
            if (src[1] == '\0') {
                /* Ignore trailing '.' */
                break;
            } else if (src[1] == '/') {
                /* Skip './'. */
                src += 2;
                continue;
            } else if (src[1] == '.') {
                if (src[2] == '/' || src[2] == '\0') {
                    /* Conditionally warn about '..' */
                    if (a->flags & ARCHIVE_EXTRACT_SECURE_NODOTDOT) {
                        archive_set_error(&a->archive,
                            ARCHIVE_ERRNO_MISC,
                            "Path contains '..'");
                        return (ARCHIVE_FAILED);
                    }
                }
                /*
                 * Note: Under no circumstances do we
                 * remove '..' elements.  In
                 * particular, restoring
                 * '/foo/../bar/' should create the
                 * 'foo' dir as a side-effect.
                 */
            }
        }

        /* Copy current element, including leading '/'. */
        if (separator)
            *dest++ = '/';
        while (*src != '\0' && *src != '/') {
            *dest++ = *src++;
        }

        if (*src == '\0')
            break;

        /* Skip '/' separator. */
        separator = *src++;
    }
    /*
     * We've just copied zero or more path elements, not including the
     * final '/'.
     */
    if (dest == a->name) {
        /*
         * Nothing got copied.  The path must have been something
         * like '.' or '/' or './' or '/././././/./'.
         */
        if (separator)
            *dest++ = '/';
        else
            *dest++ = '.';
    }
    /* Terminate the result. */
    *dest = '\0';
    return (ARCHIVE_OK);
}

/*
 * Create the parent directory of the specified path, assuming path
 * is already in mutable storage.
 */
static int
create_parent_dir(struct archive_write_disk *a, char *path)
{
    char *slash;
    int r;

    /* Remove tail element to obtain parent name. */
    slash = strrchr(path, '/');
    if (slash == NULL)
        return (ARCHIVE_OK);
    *slash = '\0';
    r = create_dir(a, path);
    *slash = '/';
    return (r);
}

/*
 * Create the specified dir, recursing to create parents as necessary.
 *
 * Returns ARCHIVE_OK if the path exists when we're done here.
 * Otherwise, returns ARCHIVE_FAILED.
 * Assumes path is in mutable storage; path is unchanged on exit.
 */
static int
create_dir(struct archive_write_disk *a, char *path)
{
    struct stat st;
    struct fixup_entry *le;
    char *slash, *base;
    mode_t mode_final, mode;
    int r;

    r = ARCHIVE_OK;

    /* Check for special names and just skip them. */
    slash = strrchr(path, '/');
    if (slash == NULL)
        base = path;
    else
        base = slash + 1;

    if (base[0] == '\0' ||
        (base[0] == '.' && base[1] == '\0') ||
        (base[0] == '.' && base[1] == '.' && base[2] == '\0')) {
        /* Don't bother trying to create null path, '.', or '..'. */
        if (slash != NULL) {
            *slash = '\0';
            r = create_dir(a, path);
            *slash = '/';
            return (r);
        }
        return (ARCHIVE_OK);
    }

    /*
     * Yes, this should be stat() and not lstat().  Using lstat()
     * here loses the ability to extract through symlinks.  Also note
     * that this should not use the a->st cache.
     */
    if (stat(path, &st) == 0) {
        if (S_ISDIR(st.st_mode))
            return (ARCHIVE_OK);
        if ((a->flags & ARCHIVE_EXTRACT_NO_OVERWRITE)) {
            archive_set_error(&a->archive, EEXIST,
                "Can't create directory '%s'", path);
            return (ARCHIVE_FAILED);
        }
        if (unlink(path) != 0) {
            archive_set_error(&a->archive, errno,
                "Can't create directory '%s': "
                "Conflicting file cannot be removed");
            return (ARCHIVE_FAILED);
        }
    } else if (errno != ENOENT && errno != ENOTDIR) {
        /* Stat failed? */
        archive_set_error(&a->archive, errno, "Can't test directory '%s'", path);
        return (ARCHIVE_FAILED);
    } else if (slash != NULL) {
        *slash = '\0';
        r = create_dir(a, path);
        *slash = '/';
        if (r != ARCHIVE_OK)
            return (r);
    }

    /*
     * Mode we want for the final restored directory.  Per POSIX,
     * implicitly-created dirs must be created obeying the umask.
     * There's no mention whether this is different for privileged
     * restores (which the rest of this code handles by pretending
     * umask=0).  I've chosen here to always obey the user's umask for
     * implicit dirs, even if _EXTRACT_PERM was specified.
     */
    mode_final = DEFAULT_DIR_MODE & ~a->user_umask;
    /* Mode we want on disk during the restore process. */
    mode = mode_final;
    mode |= MINIMUM_DIR_MODE;
    mode &= MAXIMUM_DIR_MODE;
    if (mkdir(path, mode) == 0) {
        if (mode != mode_final) {
            le = new_fixup(a, path);
            le->fixup |=TODO_MODE_BASE;
            le->mode = mode_final;
        }
        return (ARCHIVE_OK);
    }

    /*
     * Without the following check, a/b/../b/c/d fails at the
     * second visit to 'b', so 'd' can't be created.  Note that we
     * don't add it to the fixup list here, as it's already been
     * added.
     */
    if (stat(path, &st) == 0 && S_ISDIR(st.st_mode))
        return (ARCHIVE_OK);

    archive_set_error(&a->archive, errno, "Failed to create dir '%s'",
        path);
    return (ARCHIVE_FAILED);
}

/*
 * Note: Although we can skip setting the user id if the desired user
 * id matches the current user, we cannot skip setting the group, as
 * many systems set the gid based on the containing directory.  So
 * we have to perform a chown syscall if we want to set the SGID
 * bit.  (The alternative is to stat() and then possibly chown(); it's
 * more efficient to skip the stat() and just always chown().)  Note
 * that a successful chown() here clears the TODO_SGID_CHECK bit, which
 * allows set_mode to skip the stat() check for the GID.
 */
static int
set_ownership(struct archive_write_disk *a)
{
#ifndef __CYGWIN__
/* unfortunately, on win32 there is no 'root' user with uid 0,
   so we just have to try the chown and see if it works */

    /* If we know we can't change it, don't bother trying. */
    if (a->user_uid != 0  &&  a->user_uid != a->uid) {
        archive_set_error(&a->archive, errno,
            "Can't set UID=%d", a->uid);
        return (ARCHIVE_WARN);
    }
#endif

#ifdef HAVE_FCHOWN
    /* If we have an fd, we can avoid a race. */
    if (a->fd >= 0 && fchown(a->fd, a->uid, a->gid) == 0) {
        /* We've set owner and know uid/gid are correct. */
        a->todo &= ~(TODO_OWNER | TODO_SGID_CHECK | TODO_SUID_CHECK);
        return (ARCHIVE_OK);
    }
#endif

    /* We prefer lchown() but will use chown() if that's all we have. */
    /* Of course, if we have neither, this will always fail. */
#ifdef HAVE_LCHOWN
    if (lchown(a->name, a->uid, a->gid) == 0) {
        /* We've set owner and know uid/gid are correct. */
        a->todo &= ~(TODO_OWNER | TODO_SGID_CHECK | TODO_SUID_CHECK);
        return (ARCHIVE_OK);
    }
#elif HAVE_CHOWN
    if (!S_ISLNK(a->mode) && chown(a->name, a->uid, a->gid) == 0) {
        /* We've set owner and know uid/gid are correct. */
        a->todo &= ~(TODO_OWNER | TODO_SGID_CHECK | TODO_SUID_CHECK);
        return (ARCHIVE_OK);
    }
#endif

    archive_set_error(&a->archive, errno,
        "Can't set user=%d/group=%d for %s", a->uid, a->gid,
        a->name);
    return (ARCHIVE_WARN);
}

#ifdef HAVE_UTIMES
/*
 * The utimes()-family functions provide high resolution and
 * a way to set time on an fd or a symlink.  We prefer them
 * when they're available.
 */
static int
set_time(int fd, int mode, const char *name,
    time_t atime, long atime_nsec,
    time_t mtime, long mtime_nsec)
{
#if defined(_WIN32) && !defined(__CYGWIN__)
    struct __timeval times[2];
#else
    struct timeval times[2];
#endif

    times[0].tv_sec = atime;
    times[0].tv_usec = atime_nsec / 1000;
    times[1].tv_sec = mtime;
    times[1].tv_usec = mtime_nsec / 1000;

#ifdef HAVE_FUTIMES
    if (fd >= 0)
        return (futimes(fd, times));
#else
    (void)fd; /* UNUSED */
#endif
#ifdef HAVE_LUTIMES
    (void)mode; /* UNUSED */
    return (lutimes(name, times));
#else
    if (S_ISLNK(mode))
        return (0);
    return (utimes(name, times));
#endif
}
#elif defined(HAVE_UTIME)
/*
 * utime() is an older, more standard interface that we'll use
 * if utimes() isn't available.
 */
static int
set_time(int fd, int mode, const char *name,
    time_t atime, long atime_nsec,
    time_t mtime, long mtime_nsec)
{
    struct utimbuf times;
    (void)fd; /* UNUSED */
    (void)name; /* UNUSED */
    (void)atime_nsec; /* UNUSED */
    (void)mtime_nsec; /* UNUSED */
    times.actime = atime;
    times.modtime = mtime;
    if (S_ISLNK(mode))
        return (ARCHIVE_OK);
    return (utime(name, &times));
}
#else
static int
set_time(int fd, int mode, const char *name,
    time_t atime, long atime_nsec,
    time_t mtime, long mtime_nsec)
{
    return (ARCHIVE_WARN);
}
#endif

static int
set_times(struct archive_write_disk *a)
{
    time_t atime = a->start_time, mtime = a->start_time;
    long atime_nsec = 0, mtime_nsec = 0;

    /* If no time was provided, we're done. */
    if (!archive_entry_atime_is_set(a->entry)
#if HAVE_STRUCT_STAT_ST_BIRTHTIME
        && !archive_entry_birthtime_is_set(a->entry)
#endif
        && !archive_entry_mtime_is_set(a->entry))
        return (ARCHIVE_OK);

    /* If no atime was specified, use start time instead. */
    /* In theory, it would be marginally more correct to use
     * time(NULL) here, but that would cost us an extra syscall
     * for little gain. */
    if (archive_entry_atime_is_set(a->entry)) {
        atime = archive_entry_atime(a->entry);
        atime_nsec = archive_entry_atime_nsec(a->entry);
    }

    /*
     * If you have struct stat.st_birthtime, we assume BSD birthtime
     * semantics, in which {f,l,}utimes() updates birthtime to earliest
     * mtime.  So we set the time twice, first using the birthtime,
     * then using the mtime.
     */
#if HAVE_STRUCT_STAT_ST_BIRTHTIME
    /* If birthtime is set, flush that through to disk first. */
    if (archive_entry_birthtime_is_set(a->entry))
        if (set_time(a->fd, a->mode, a->name, atime, atime_nsec,
            archive_entry_birthtime(a->entry),
            archive_entry_birthtime_nsec(a->entry))) {
            archive_set_error(&a->archive, errno,
                "Can't update time for %s",
                a->name);
            return (ARCHIVE_WARN);
        }
#endif

    if (archive_entry_mtime_is_set(a->entry)) {
        mtime = archive_entry_mtime(a->entry);
        mtime_nsec = archive_entry_mtime_nsec(a->entry);
    }
    if (set_time(a->fd, a->mode, a->name,
        atime, atime_nsec, mtime, mtime_nsec)) {
        archive_set_error(&a->archive, errno,
            "Can't update time for %s",
            a->name);
        return (ARCHIVE_WARN);
    }

    /*
     * Note: POSIX does not provide a portable way to restore ctime.
     * (Apart from resetting the system clock, which is distasteful.)
     * So, any restoration of ctime will necessarily be OS-specific.
     */

    return (ARCHIVE_OK);
}

static int
set_mode(struct archive_write_disk *a, int mode)
{
    int r = ARCHIVE_OK;
    mode &= 07777; /* Strip off file type bits. */

    if (a->todo & TODO_SGID_CHECK) {
        /*
         * If we don't know the GID is right, we must stat()
         * to verify it.  We can't just check the GID of this
         * process, since systems sometimes set GID from
         * the enclosing dir or based on ACLs.
         */
        if ((r = _archive_write_disk_lazy_stat(a)) != ARCHIVE_OK)
            return (r);
        if (a->pst->st_gid != a->gid) {
            mode &= ~ S_ISGID;
#if !defined(_WIN32) || defined(__CYGWIN__)
            if (a->flags & ARCHIVE_EXTRACT_OWNER) {
                /*
                 * This is only an error if you
                 * requested owner restore.  If you
                 * didn't, we'll try to restore
                 * sgid/suid, but won't consider it a
                 * problem if we can't.
                 */
                archive_set_error(&a->archive, -1,
                    "Can't restore SGID bit");
                r = ARCHIVE_WARN;
            }
#endif
        }
        /* While we're here, double-check the UID. */
        if (a->pst->st_uid != a->uid
            && (a->todo & TODO_SUID)) {
            mode &= ~ S_ISUID;
#if !defined(_WIN32) || defined(__CYGWIN__)
            if (a->flags & ARCHIVE_EXTRACT_OWNER) {
                archive_set_error(&a->archive, -1,
                    "Can't restore SUID bit");
                r = ARCHIVE_WARN;
            }
#endif
        }
        a->todo &= ~TODO_SGID_CHECK;
        a->todo &= ~TODO_SUID_CHECK;
    } else if (a->todo & TODO_SUID_CHECK) {
        /*
         * If we don't know the UID is right, we can just check
         * the user, since all systems set the file UID from
         * the process UID.
         */
        if (a->user_uid != a->uid) {
            mode &= ~ S_ISUID;
#if !defined(_WIN32) || defined(__CYGWIN__)
            if (a->flags & ARCHIVE_EXTRACT_OWNER) {
                archive_set_error(&a->archive, -1,
                    "Can't make file SUID");
                r = ARCHIVE_WARN;
            }
#endif
        }
        a->todo &= ~TODO_SUID_CHECK;
    }

    if (S_ISLNK(a->mode)) {
#ifdef HAVE_LCHMOD
        /*
         * If this is a symlink, use lchmod().  If the
         * platform doesn't support lchmod(), just skip it.  A
         * platform that doesn't provide a way to set
         * permissions on symlinks probably ignores
         * permissions on symlinks, so a failure here has no
         * impact.
         */
        if (lchmod(a->name, mode) != 0) {
            archive_set_error(&a->archive, errno,
                "Can't set permissions to 0%o", (int)mode);
            r = ARCHIVE_WARN;
        }
#endif
    } else if (!S_ISDIR(a->mode)) {
        /*
         * If it's not a symlink and not a dir, then use
         * fchmod() or chmod(), depending on whether we have
         * an fd.  Dirs get their perms set during the
         * post-extract fixup, which is handled elsewhere.
         */
#ifdef HAVE_FCHMOD
        if (a->fd >= 0) {
            if (fchmod(a->fd, mode) != 0) {
                archive_set_error(&a->archive, errno,
                    "Can't set permissions to 0%o", (int)mode);
                r = ARCHIVE_WARN;
            }
        } else
#endif
            /* If this platform lacks fchmod(), then
             * we'll just use chmod(). */
            if (chmod(a->name, mode) != 0) {
                archive_set_error(&a->archive, errno,
                    "Can't set permissions to 0%o", (int)mode);
                r = ARCHIVE_WARN;
            }
    }
    return (r);
}

static int
set_fflags(struct archive_write_disk *a)
{
    struct fixup_entry *le;
    unsigned long   set, clear;
    int     r;
    int     critical_flags;
    mode_t      mode = archive_entry_mode(a->entry);

    /*
     * Make 'critical_flags' hold all file flags that can't be
     * immediately restored.  For example, on BSD systems,
     * SF_IMMUTABLE prevents hardlinks from being created, so
     * should not be set until after any hardlinks are created.  To
     * preserve some semblance of portability, this uses #ifdef
     * extensively.  Ugly, but it works.
     *
     * Yes, Virginia, this does create a security race.  It's mitigated
     * somewhat by the practice of creating dirs 0700 until the extract
     * is done, but it would be nice if we could do more than that.
     * People restoring critical file systems should be wary of
     * other programs that might try to muck with files as they're
     * being restored.
     */
    /* Hopefully, the compiler will optimize this mess into a constant. */
    critical_flags = 0;
#ifdef SF_IMMUTABLE
    critical_flags |= SF_IMMUTABLE;
#endif
#ifdef UF_IMMUTABLE
    critical_flags |= UF_IMMUTABLE;
#endif
#ifdef SF_APPEND
    critical_flags |= SF_APPEND;
#endif
#ifdef UF_APPEND
    critical_flags |= UF_APPEND;
#endif
#ifdef EXT2_APPEND_FL
    critical_flags |= EXT2_APPEND_FL;
#endif
#ifdef EXT2_IMMUTABLE_FL
    critical_flags |= EXT2_IMMUTABLE_FL;
#endif

    if (a->todo & TODO_FFLAGS) {
        archive_entry_fflags(a->entry, &set, &clear);

        /*
         * The first test encourages the compiler to eliminate
         * all of this if it's not necessary.
         */
        if ((critical_flags != 0)  &&  (set & critical_flags)) {
            le = current_fixup(a, a->name);
            le->fixup |= TODO_FFLAGS;
            le->fflags_set = set;
            /* Store the mode if it's not already there. */
            if ((le->fixup & TODO_MODE) == 0)
                le->mode = mode;
        } else {
            r = set_fflags_platform(a, a->fd,
                a->name, mode, set, clear);
            if (r != ARCHIVE_OK)
                return (r);
        }
    }
    return (ARCHIVE_OK);
}


#if ( defined(HAVE_LCHFLAGS) || defined(HAVE_CHFLAGS) || defined(HAVE_FCHFLAGS) ) && defined(HAVE_STRUCT_STAT_ST_FLAGS)
/*
 * BSD reads flags using stat() and sets them with one of {f,l,}chflags()
 */
static int
set_fflags_platform(struct archive_write_disk *a, int fd, const char *name,
    mode_t mode, unsigned long set, unsigned long clear)
{
    int r;

    (void)mode; /* UNUSED */
    if (set == 0  && clear == 0)
        return (ARCHIVE_OK);

    /*
     * XXX Is the stat here really necessary?  Or can I just use
     * the 'set' flags directly?  In particular, I'm not sure
     * about the correct approach if we're overwriting an existing
     * file that already has flags on it. XXX
     */
    if ((r = _archive_write_disk_lazy_stat(a)) != ARCHIVE_OK)
        return (r);

    a->st.st_flags &= ~clear;
    a->st.st_flags |= set;
#ifdef HAVE_FCHFLAGS
    /* If platform has fchflags() and we were given an fd, use it. */
    if (fd >= 0 && fchflags(fd, a->st.st_flags) == 0)
        return (ARCHIVE_OK);
#endif
    /*
     * If we can't use the fd to set the flags, we'll use the
     * pathname to set flags.  We prefer lchflags() but will use
     * chflags() if we must.
     */
#ifdef HAVE_LCHFLAGS
    if (lchflags(name, a->st.st_flags) == 0)
        return (ARCHIVE_OK);
#elif defined(HAVE_CHFLAGS)
    if (S_ISLNK(a->st.st_mode)) {
        archive_set_error(&a->archive, errno,
            "Can't set file flags on symlink.");
        return (ARCHIVE_WARN);
    }
    if (chflags(name, a->st.st_flags) == 0)
        return (ARCHIVE_OK);
#endif
    archive_set_error(&a->archive, errno,
        "Failed to set file flags");
    return (ARCHIVE_WARN);
}

#elif defined(EXT2_IOC_GETFLAGS) && defined(EXT2_IOC_SETFLAGS)
/*
 * Linux uses ioctl() to read and write file flags.
 */
static int
set_fflags_platform(struct archive_write_disk *a, int fd, const char *name,
    mode_t mode, unsigned long set, unsigned long clear)
{
    int      ret;
    int      myfd = fd;
    unsigned long newflags, oldflags;
    unsigned long sf_mask = 0;

    if (set == 0  && clear == 0)
        return (ARCHIVE_OK);
    /* Only regular files and dirs can have flags. */
    if (!S_ISREG(mode) && !S_ISDIR(mode))
        return (ARCHIVE_OK);

    /* If we weren't given an fd, open it ourselves. */
    if (myfd < 0)
        myfd = open(name, O_RDONLY | O_NONBLOCK | O_BINARY);
    if (myfd < 0)
        return (ARCHIVE_OK);

    /*
     * Linux has no define for the flags that are only settable by
     * the root user.  This code may seem a little complex, but
     * there seem to be some Linux systems that lack these
     * defines. (?)  The code below degrades reasonably gracefully
     * if sf_mask is incomplete.
     */
#ifdef EXT2_IMMUTABLE_FL
    sf_mask |= EXT2_IMMUTABLE_FL;
#endif
#ifdef EXT2_APPEND_FL
    sf_mask |= EXT2_APPEND_FL;
#endif
    /*
     * XXX As above, this would be way simpler if we didn't have
     * to read the current flags from disk. XXX
     */
    ret = ARCHIVE_OK;
    /* Try setting the flags as given. */
    if (ioctl(myfd, EXT2_IOC_GETFLAGS, &oldflags) >= 0) {
        newflags = (oldflags & ~clear) | set;
        if (ioctl(myfd, EXT2_IOC_SETFLAGS, &newflags) >= 0)
            goto cleanup;
        if (errno != EPERM)
            goto fail;
    }
    /* If we couldn't set all the flags, try again with a subset. */
    if (ioctl(myfd, EXT2_IOC_GETFLAGS, &oldflags) >= 0) {
        newflags &= ~sf_mask;
        oldflags &= sf_mask;
        newflags |= oldflags;
        if (ioctl(myfd, EXT2_IOC_SETFLAGS, &newflags) >= 0)
            goto cleanup;
    }
    /* We couldn't set the flags, so report the failure. */
fail:
    archive_set_error(&a->archive, errno,
        "Failed to set file flags");
    ret = ARCHIVE_WARN;
cleanup:
    if (fd < 0)
        close(myfd);
    return (ret);
}

#else

/*
 * Of course, some systems have neither BSD chflags() nor Linux' flags
 * support through ioctl().
 */
static int
set_fflags_platform(struct archive_write_disk *a, int fd, const char *name,
    mode_t mode, unsigned long set, unsigned long clear)
{
    (void)a; /* UNUSED */
    (void)fd; /* UNUSED */
    (void)name; /* UNUSED */
    (void)mode; /* UNUSED */
    (void)set; /* UNUSED */
    (void)clear; /* UNUSED */
    return (ARCHIVE_OK);
}

#endif /* __linux */

#ifndef HAVE_POSIX_ACL
/* Default empty function body to satisfy mainline code. */
static int
set_acls(struct archive_write_disk *a)
{
    (void)a; /* UNUSED */
    return (ARCHIVE_OK);
}

#else

/*
 * XXX TODO: What about ACL types other than ACCESS and DEFAULT?
 */
static int
set_acls(struct archive_write_disk *a)
{
    int      ret;

    ret = set_acl(a, a->fd, a->entry, ACL_TYPE_ACCESS,
        ARCHIVE_ENTRY_ACL_TYPE_ACCESS, "access");
    if (ret != ARCHIVE_OK)
        return (ret);
    ret = set_acl(a, a->fd, a->entry, ACL_TYPE_DEFAULT,
        ARCHIVE_ENTRY_ACL_TYPE_DEFAULT, "default");
    return (ret);
}


static int
set_acl(struct archive_write_disk *a, int fd, struct archive_entry *entry,
    acl_type_t acl_type, int ae_requested_type, const char *tname)
{
    acl_t        acl;
    acl_entry_t  acl_entry;
    acl_permset_t    acl_permset;
    int      ret;
    int      ae_type, ae_permset, ae_tag, ae_id;
    uid_t        ae_uid;
    gid_t        ae_gid;
    const char  *ae_name;
    int      entries;
    const char  *name;

    ret = ARCHIVE_OK;
    entries = archive_entry_acl_reset(entry, ae_requested_type);
    if (entries == 0)
        return (ARCHIVE_OK);
    acl = acl_init(entries);
    while (archive_entry_acl_next(entry, ae_requested_type, &ae_type,
           &ae_permset, &ae_tag, &ae_id, &ae_name) == ARCHIVE_OK) {
        acl_create_entry(&acl, &acl_entry);

        switch (ae_tag) {
        case ARCHIVE_ENTRY_ACL_USER:
            acl_set_tag_type(acl_entry, ACL_USER);
            ae_uid = a->lookup_uid(a->lookup_uid_data,
                ae_name, ae_id);
            acl_set_qualifier(acl_entry, &ae_uid);
            break;
        case ARCHIVE_ENTRY_ACL_GROUP:
            acl_set_tag_type(acl_entry, ACL_GROUP);
            ae_gid = a->lookup_gid(a->lookup_gid_data,
                ae_name, ae_id);
            acl_set_qualifier(acl_entry, &ae_gid);
            break;
        case ARCHIVE_ENTRY_ACL_USER_OBJ:
            acl_set_tag_type(acl_entry, ACL_USER_OBJ);
            break;
        case ARCHIVE_ENTRY_ACL_GROUP_OBJ:
            acl_set_tag_type(acl_entry, ACL_GROUP_OBJ);
            break;
        case ARCHIVE_ENTRY_ACL_MASK:
            acl_set_tag_type(acl_entry, ACL_MASK);
            break;
        case ARCHIVE_ENTRY_ACL_OTHER:
            acl_set_tag_type(acl_entry, ACL_OTHER);
            break;
        default:
            /* XXX */
            break;
        }

        acl_get_permset(acl_entry, &acl_permset);
        acl_clear_perms(acl_permset);
        if (ae_permset & ARCHIVE_ENTRY_ACL_EXECUTE)
            acl_add_perm(acl_permset, ACL_EXECUTE);
        if (ae_permset & ARCHIVE_ENTRY_ACL_WRITE)
            acl_add_perm(acl_permset, ACL_WRITE);
        if (ae_permset & ARCHIVE_ENTRY_ACL_READ)
            acl_add_perm(acl_permset, ACL_READ);
    }

    name = archive_entry_pathname(entry);

    /* Try restoring the ACL through 'fd' if we can. */
#if HAVE_ACL_SET_FD
    if (fd >= 0 && acl_type == ACL_TYPE_ACCESS && acl_set_fd(fd, acl) == 0)
        ret = ARCHIVE_OK;
    else
#else
#if HAVE_ACL_SET_FD_NP
    if (fd >= 0 && acl_set_fd_np(fd, acl, acl_type) == 0)
        ret = ARCHIVE_OK;
    else
#endif
#endif
    if (acl_set_file(name, acl_type, acl) != 0) {
        archive_set_error(&a->archive, errno, "Failed to set %s acl", tname);
        ret = ARCHIVE_WARN;
    }
    acl_free(acl);
    return (ret);
}
#endif

#if HAVE_LSETXATTR
/*
 * Restore extended attributes -  Linux implementation
 */
static int
set_xattrs(struct archive_write_disk *a)
{
    struct archive_entry *entry = a->entry;
    static int warning_done = 0;
    int ret = ARCHIVE_OK;
    int i = archive_entry_xattr_reset(entry);

    while (i--) {
        const char *name;
        const void *value;
        size_t size;
        archive_entry_xattr_next(entry, &name, &value, &size);
        if (name != NULL &&
                strncmp(name, "xfsroot.", 8) != 0 &&
                strncmp(name, "system.", 7) != 0) {
            int e;
#if HAVE_FSETXATTR
            if (a->fd >= 0)
                e = fsetxattr(a->fd, name, value, size, 0);
            else
#endif
            {
                e = lsetxattr(archive_entry_pathname(entry),
                    name, value, size, 0);
            }
            if (e == -1) {
                if (errno == ENOTSUP) {
                    if (!warning_done) {
                        warning_done = 1;
                        archive_set_error(&a->archive, errno,
                            "Cannot restore extended "
                            "attributes on this file "
                            "system");
                    }
                } else
                    archive_set_error(&a->archive, errno,
                        "Failed to set extended attribute");
                ret = ARCHIVE_WARN;
            }
        } else {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
                "Invalid extended attribute encountered");
            ret = ARCHIVE_WARN;
        }
    }
    return (ret);
}
#elif HAVE_EXTATTR_SET_FILE
/*
 * Restore extended attributes -  FreeBSD implementation
 */
static int
set_xattrs(struct archive_write_disk *a)
{
    struct archive_entry *entry = a->entry;
    static int warning_done = 0;
    int ret = ARCHIVE_OK;
    int i = archive_entry_xattr_reset(entry);

    while (i--) {
        const char *name;
        const void *value;
        size_t size;
        archive_entry_xattr_next(entry, &name, &value, &size);
        if (name != NULL) {
            int e;
            int namespace;

            if (strncmp(name, "user.", 5) == 0) {
                /* "user." attributes go to user namespace */
                name += 5;
                namespace = EXTATTR_NAMESPACE_USER;
            } else {
                /* Warn about other extended attributes. */
                archive_set_error(&a->archive,
                    ARCHIVE_ERRNO_FILE_FORMAT,
                    "Can't restore extended attribute ``%s''",
                    name);
                ret = ARCHIVE_WARN;
                continue;
            }
            errno = 0;
#if HAVE_EXTATTR_SET_FD
            if (a->fd >= 0)
                e = extattr_set_fd(a->fd, namespace, name, value, size);
            else
#endif
            /* TODO: should we use extattr_set_link() instead? */
            {
                e = extattr_set_file(archive_entry_pathname(entry),
                    namespace, name, value, size);
            }
            if (e != (int)size) {
                if (errno == ENOTSUP) {
                    if (!warning_done) {
                        warning_done = 1;
                        archive_set_error(&a->archive, errno,
                            "Cannot restore extended "
                            "attributes on this file "
                            "system");
                    }
                } else {
                    archive_set_error(&a->archive, errno,
                        "Failed to set extended attribute");
                }

                ret = ARCHIVE_WARN;
            }
        }
    }
    return (ret);
}
#else
/*
 * Restore extended attributes - stub implementation for unsupported systems
 */
static int
set_xattrs(struct archive_write_disk *a)
{
    static int warning_done = 0;

    /* If there aren't any extended attributes, then it's okay not
     * to extract them, otherwise, issue a single warning. */
    if (archive_entry_xattr_count(a->entry) != 0 && !warning_done) {
        warning_done = 1;
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
            "Cannot restore extended attributes on this system");
        return (ARCHIVE_WARN);
    }
    /* Warning was already emitted; suppress further warnings. */
    return (ARCHIVE_OK);
}
#endif


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

static uid_t
trivial_lookup_uid(void *private_data, const char *uname, uid_t uid)
{
    (void)private_data; /* UNUSED */
    (void)uname; /* UNUSED */
    return (uid);
}

/*
 * Test if file on disk is older than entry.
 */
static int
older(struct stat *st, struct archive_entry *entry)
{
    /* First, test the seconds and return if we have a definite answer. */
    /* Definitely older. */
    if (st->st_mtime < archive_entry_mtime(entry))
        return (1);
    /* Definitely younger. */
    if (st->st_mtime > archive_entry_mtime(entry))
        return (0);
    /* If this platform supports fractional seconds, try those. */
#if HAVE_STRUCT_STAT_ST_MTIMESPEC_TV_NSEC
    /* Definitely older. */
    if (st->st_mtimespec.tv_nsec < archive_entry_mtime_nsec(entry))
        return (1);
#elif HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
    /* Definitely older. */
    if (st->st_mtim.tv_nsec < archive_entry_mtime_nsec(entry))
        return (1);
#elif HAVE_STRUCT_STAT_ST_MTIME_N
    /* older. */
    if (st->st_mtime_n < archive_entry_mtime_nsec(entry))
        return (1);
#elif HAVE_STRUCT_STAT_ST_UMTIME
    /* older. */
    if (st->st_umtime * 1000 < archive_entry_mtime_nsec(entry))
        return (1);
#elif HAVE_STRUCT_STAT_ST_MTIME_USEC
    /* older. */
    if (st->st_mtime_usec * 1000 < archive_entry_mtime_nsec(entry))
        return (1);
#else
    /* This system doesn't have high-res timestamps. */
#endif
    /* Same age or newer, so not older. */
    return (0);
}