Import libarchive and bsdtar version 2.0.25

[dragonfly/port-amd64.git] / contrib / libarchive-2.0 / tar / write.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.
 * 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 "bsdtar_platform.h"
__FBSDID("$FreeBSD: src/usr.bin/tar/write.c,v 1.55 2007/03/11 10:36:42 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_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_ATTR_XATTR_H
#include <attr/xattr.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_EXT2FS_EXT2_FS_H
#include <ext2fs/ext2_fs.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_FNMATCH_H
#include <fnmatch.h>
#endif
#ifdef HAVE_GRP_H
#include <grp.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_LINUX_FS_H
#include <linux/fs.h>   /* for Linux file flags */
#endif
#ifdef HAVE_LINUX_EXT2_FS_H
#include <linux/ext2_fs.h>      /* for Linux file flags */
#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

#include "bsdtar.h"
#include "tree.h"

/* Fixed size of uname/gname caches. */
#define name_cache_size 101

static const char * const NO_NAME = "(noname)";

/* Initial size of link cache. */
#define links_cache_initial_size 1024

struct archive_dir_entry {
        struct archive_dir_entry        *next;
        time_t                   mtime_sec;
        int                      mtime_nsec;
        char                    *name;
};

struct archive_dir {
        struct archive_dir_entry *head, *tail;
};

struct links_cache {
        unsigned long             number_entries;
        size_t                    number_buckets;
        struct links_entry      **buckets;
};

struct links_entry {
        struct links_entry      *next;
        struct links_entry      *previous;
        int                      links;
        dev_t                    dev;
        ino_t                    ino;
        char                    *name;
};

struct name_cache {
        int     probes;
        int     hits;
        size_t  size;
        struct {
                id_t id;
                const char *name;
        } cache[name_cache_size];
};

static void              add_dir_list(struct bsdtar *bsdtar, const char *path,
                             time_t mtime_sec, int mtime_nsec);
static int               append_archive(struct bsdtar *, struct archive *,
                             const char *fname);
static void              archive_names_from_file(struct bsdtar *bsdtar,
                             struct archive *a);
static int               archive_names_from_file_helper(struct bsdtar *bsdtar,
                             const char *line);
static void              create_cleanup(struct bsdtar *);
static void              free_buckets(struct bsdtar *, struct links_cache *);
static void              free_cache(struct name_cache *cache);
static const char *      lookup_gname(struct bsdtar *bsdtar, gid_t gid);
static int               lookup_gname_helper(struct bsdtar *bsdtar,
                             const char **name, id_t gid);
static void              lookup_hardlink(struct bsdtar *,
                             struct archive_entry *entry, const struct stat *);
static const char *      lookup_uname(struct bsdtar *bsdtar, uid_t uid);
static int               lookup_uname_helper(struct bsdtar *bsdtar,
                             const char **name, id_t uid);
static int               new_enough(struct bsdtar *, const char *path,
                             const struct stat *);
static void              setup_acls(struct bsdtar *, struct archive_entry *,
                             const char *path);
static void              setup_xattrs(struct bsdtar *, struct archive_entry *,
                             const char *path);
static void              test_for_append(struct bsdtar *);
static void              write_archive(struct archive *, struct bsdtar *);
static void              write_entry(struct bsdtar *, struct archive *,
                             const struct stat *, const char *pathname,
                             unsigned pathlen, const char *accpath);
static int               write_file_data(struct bsdtar *, struct archive *,
                             int fd);
static void              write_hierarchy(struct bsdtar *, struct archive *,
                             const char *);

void
tar_mode_c(struct bsdtar *bsdtar)
{
        struct archive *a;
        int r;

        if (*bsdtar->argv == NULL && bsdtar->names_from_file == NULL)
                bsdtar_errc(bsdtar, 1, 0, "no files or directories specified");

        a = archive_write_new();

        /* Support any format that the library supports. */
        if (bsdtar->create_format == NULL) {
                r = archive_write_set_format_pax_restricted(a);
                bsdtar->create_format = "pax restricted";
        } else {
                r = archive_write_set_format_by_name(a, bsdtar->create_format);
        }
        if (r != ARCHIVE_OK) {
                fprintf(stderr, "Can't use format %s: %s\n",
                    bsdtar->create_format,
                    archive_error_string(a));
                usage(bsdtar);
        }

        /*
         * If user explicitly set the block size, then assume they
         * want the last block padded as well.  Otherwise, use the
         * default block size and accept archive_write_open_file()'s
         * default padding decisions.
         */
        if (bsdtar->bytes_per_block != 0) {
                archive_write_set_bytes_per_block(a, bsdtar->bytes_per_block);
                archive_write_set_bytes_in_last_block(a,
                    bsdtar->bytes_per_block);
        } else
                archive_write_set_bytes_per_block(a, DEFAULT_BYTES_PER_BLOCK);

        switch (bsdtar->create_compression) {
        case 0:
                break;
#ifdef HAVE_LIBBZ2
        case 'j': case 'y':
                archive_write_set_compression_bzip2(a);
                break;
#endif
#ifdef HAVE_LIBZ
        case 'z':
                archive_write_set_compression_gzip(a);
                break;
#endif
        default:
                bsdtar_errc(bsdtar, 1, 0,
                    "Unrecognized compression option -%c",
                    bsdtar->create_compression);
        }

        r = archive_write_open_file(a, bsdtar->filename);
        if (r != ARCHIVE_OK)
                bsdtar_errc(bsdtar, 1, 0, archive_error_string(a));

        write_archive(a, bsdtar);

        if (bsdtar->option_totals) {
                fprintf(stderr, "Total bytes written: " BSDTAR_FILESIZE_PRINTF "\n",
                    (BSDTAR_FILESIZE_TYPE)archive_position_compressed(a));
        }

        archive_write_finish(a);
}

/*
 * Same as 'c', except we only support tar or empty formats in
 * uncompressed files on disk.
 */
void
tar_mode_r(struct bsdtar *bsdtar)
{
        off_t   end_offset;
        int     format;
        struct archive *a;
        struct archive_entry *entry;
        int     r;

        /* Sanity-test some arguments and the file. */
        test_for_append(bsdtar);

        format = ARCHIVE_FORMAT_TAR_PAX_RESTRICTED;

        bsdtar->fd = open(bsdtar->filename, O_RDWR | O_CREAT, 0666);
        if (bsdtar->fd < 0)
                bsdtar_errc(bsdtar, 1, errno,
                    "Cannot open %s", bsdtar->filename);

        a = archive_read_new();
        archive_read_support_compression_all(a);
        archive_read_support_format_tar(a);
        archive_read_support_format_gnutar(a);
        r = archive_read_open_fd(a, bsdtar->fd, 10240);
        if (r != ARCHIVE_OK)
                bsdtar_errc(bsdtar, 1, archive_errno(a),
                    "Can't read archive %s: %s", bsdtar->filename,
                    archive_error_string(a));
        while (0 == archive_read_next_header(a, &entry)) {
                if (archive_compression(a) != ARCHIVE_COMPRESSION_NONE) {
                        archive_read_finish(a);
                        close(bsdtar->fd);
                        bsdtar_errc(bsdtar, 1, 0,
                            "Cannot append to compressed archive.");
                }
                /* Keep going until we hit end-of-archive */
                format = archive_format(a);
        }

        end_offset = archive_read_header_position(a);
        archive_read_finish(a);

        /* Re-open archive for writing */
        a = archive_write_new();
        archive_write_set_compression_none(a);
        /*
         * Set the format to be used for writing.  To allow people to
         * extend empty files, we need to allow them to specify the format,
         * which opens the possibility that they will specify a format that
         * doesn't match the existing format.  Hence, the following bit
         * of arcane ugliness.
         */

        if (bsdtar->create_format != NULL) {
                /* If the user requested a format, use that, but ... */
                archive_write_set_format_by_name(a,
                    bsdtar->create_format);
                /* ... complain if it's not compatible. */
                format &= ARCHIVE_FORMAT_BASE_MASK;
                if (format != (int)(archive_format(a) & ARCHIVE_FORMAT_BASE_MASK)
                    && format != ARCHIVE_FORMAT_EMPTY) {
                        bsdtar_errc(bsdtar, 1, 0,
                            "Format %s is incompatible with the archive %s.",
                            bsdtar->create_format, bsdtar->filename);
                }
        } else {
                /*
                 * Just preserve the current format, with a little care
                 * for formats that libarchive can't write.
                 */
                if (format == ARCHIVE_FORMAT_TAR_GNUTAR)
                        /* TODO: When gtar supports pax, use pax restricted. */
                        format = ARCHIVE_FORMAT_TAR_USTAR;
                if (format == ARCHIVE_FORMAT_EMPTY)
                        format = ARCHIVE_FORMAT_TAR_PAX_RESTRICTED;
                archive_write_set_format(a, format);
        }
        lseek(bsdtar->fd, end_offset, SEEK_SET); /* XXX check return val XXX */
        archive_write_open_fd(a, bsdtar->fd); /* XXX check return val XXX */

        write_archive(a, bsdtar); /* XXX check return val XXX */

        if (bsdtar->option_totals) {
                fprintf(stderr, "Total bytes written: " BSDTAR_FILESIZE_PRINTF "\n",
                    (BSDTAR_FILESIZE_TYPE)archive_position_compressed(a));
        }

        archive_write_finish(a);
        close(bsdtar->fd);
        bsdtar->fd = -1;
}

void
tar_mode_u(struct bsdtar *bsdtar)
{
        off_t                    end_offset;
        struct archive          *a;
        struct archive_entry    *entry;
        int                      format;
        struct archive_dir_entry        *p;
        struct archive_dir       archive_dir;

        bsdtar->archive_dir = &archive_dir;
        memset(&archive_dir, 0, sizeof(archive_dir));

        format = ARCHIVE_FORMAT_TAR_PAX_RESTRICTED;

        /* Sanity-test some arguments and the file. */
        test_for_append(bsdtar);

        bsdtar->fd = open(bsdtar->filename, O_RDWR);
        if (bsdtar->fd < 0)
                bsdtar_errc(bsdtar, 1, errno,
                    "Cannot open %s", bsdtar->filename);

        a = archive_read_new();
        archive_read_support_compression_all(a);
        archive_read_support_format_tar(a);
        archive_read_support_format_gnutar(a);
        if (archive_read_open_fd(a, bsdtar->fd,
            bsdtar->bytes_per_block != 0 ? bsdtar->bytes_per_block :
                DEFAULT_BYTES_PER_BLOCK) != ARCHIVE_OK) {
                bsdtar_errc(bsdtar, 1, 0,
                    "Can't open %s: %s", bsdtar->filename,
                    archive_error_string(a));
        }

        /* Build a list of all entries and their recorded mod times. */
        while (0 == archive_read_next_header(a, &entry)) {
                if (archive_compression(a) != ARCHIVE_COMPRESSION_NONE) {
                        archive_read_finish(a);
                        close(bsdtar->fd);
                        bsdtar_errc(bsdtar, 1, 0,
                            "Cannot append to compressed archive.");
                }
                add_dir_list(bsdtar, archive_entry_pathname(entry),
                    archive_entry_mtime(entry),
                    archive_entry_mtime_nsec(entry));
                /* Record the last format determination we see */
                format = archive_format(a);
                /* Keep going until we hit end-of-archive */
        }

        end_offset = archive_read_header_position(a);
        archive_read_finish(a);

        /* Re-open archive for writing. */
        a = archive_write_new();
        archive_write_set_compression_none(a);
        /*
         * Set format to same one auto-detected above, except that
         * we don't write GNU tar format, so use ustar instead.
         */
        if (format == ARCHIVE_FORMAT_TAR_GNUTAR)
                format = ARCHIVE_FORMAT_TAR_USTAR;
        archive_write_set_format(a, format);
        if (bsdtar->bytes_per_block != 0) {
                archive_write_set_bytes_per_block(a, bsdtar->bytes_per_block);
                archive_write_set_bytes_in_last_block(a,
                    bsdtar->bytes_per_block);
        } else
                archive_write_set_bytes_per_block(a, DEFAULT_BYTES_PER_BLOCK);
        lseek(bsdtar->fd, end_offset, SEEK_SET);
        ftruncate(bsdtar->fd, end_offset);
        archive_write_open_fd(a, bsdtar->fd);

        write_archive(a, bsdtar);

        if (bsdtar->option_totals) {
                fprintf(stderr, "Total bytes written: " BSDTAR_FILESIZE_PRINTF "\n",
                    (BSDTAR_FILESIZE_TYPE)archive_position_compressed(a));
        }

        archive_write_finish(a);
        close(bsdtar->fd);
        bsdtar->fd = -1;

        while (bsdtar->archive_dir->head != NULL) {
                p = bsdtar->archive_dir->head->next;
                free(bsdtar->archive_dir->head->name);
                free(bsdtar->archive_dir->head);
                bsdtar->archive_dir->head = p;
        }
        bsdtar->archive_dir->tail = NULL;
}


/*
 * Write user-specified files/dirs to opened archive.
 */
static void
write_archive(struct archive *a, struct bsdtar *bsdtar)
{
        const char *arg;

        if (bsdtar->names_from_file != NULL)
                archive_names_from_file(bsdtar, a);

        while (*bsdtar->argv) {
                arg = *bsdtar->argv;
                if (arg[0] == '-' && arg[1] == 'C') {
                        arg += 2;
                        if (*arg == '\0') {
                                bsdtar->argv++;
                                arg = *bsdtar->argv;
                                if (arg == NULL) {
                                        bsdtar_warnc(bsdtar, 1, 0,
                                            "Missing argument for -C");
                                        bsdtar->return_value = 1;
                                        return;
                                }
                        }
                        set_chdir(bsdtar, arg);
                } else {
                        if (*arg != '/' || (arg[0] == '@' && arg[1] != '/'))
                                do_chdir(bsdtar); /* Handle a deferred -C */
                        if (*arg == '@') {
                                if (append_archive(bsdtar, a, arg + 1) != 0)
                                        break;
                        } else
                                write_hierarchy(bsdtar, a, arg);
                }
                bsdtar->argv++;
        }

        create_cleanup(bsdtar);
        if (archive_write_close(a)) {
                bsdtar_warnc(bsdtar, 0, "%s", archive_error_string(a));
                bsdtar->return_value = 1;
        }
}

/*
 * Archive names specified in file.
 *
 * Unless --null was specified, a line containing exactly "-C" will
 * cause the next line to be a directory to pass to chdir().  If
 * --null is specified, then a line "-C" is just another filename.
 */
void
archive_names_from_file(struct bsdtar *bsdtar, struct archive *a)
{
        bsdtar->archive = a;

        bsdtar->next_line_is_dir = 0;
        process_lines(bsdtar, bsdtar->names_from_file,
            archive_names_from_file_helper);
        if (bsdtar->next_line_is_dir)
                bsdtar_errc(bsdtar, 1, errno,
                    "Unexpected end of filename list; "
                    "directory expected after -C");
}

static int
archive_names_from_file_helper(struct bsdtar *bsdtar, const char *line)
{
        if (bsdtar->next_line_is_dir) {
                set_chdir(bsdtar, line);
                bsdtar->next_line_is_dir = 0;
        } else if (!bsdtar->option_null && strcmp(line, "-C") == 0)
                bsdtar->next_line_is_dir = 1;
        else {
                if (*line != '/')
                        do_chdir(bsdtar); /* Handle a deferred -C */
                write_hierarchy(bsdtar, bsdtar->archive, line);
        }
        return (0);
}

/*
 * Copy from specified archive to current archive.  Returns non-zero
 * for write errors (which force us to terminate the entire archiving
 * operation).  If there are errors reading the input archive, we set
 * bsdtar->return_value but return zero, so the overall archiving
 * operation will complete and return non-zero.
 */
static int
append_archive(struct bsdtar *bsdtar, struct archive *a, const char *filename)
{
        struct archive *ina;
        struct archive_entry *in_entry;
        int bytes_read, bytes_written;
        char buff[8192];

        if (strcmp(filename, "-") == 0)
                filename = NULL; /* Library uses NULL for stdio. */

        ina = archive_read_new();
        archive_read_support_format_all(ina);
        archive_read_support_compression_all(ina);
        if (archive_read_open_file(ina, filename, 10240)) {
                bsdtar_warnc(bsdtar, 0, "%s", archive_error_string(ina));
                bsdtar->return_value = 1;
                return (0);
        }
        while (0 == archive_read_next_header(ina, &in_entry)) {
                if (!new_enough(bsdtar, archive_entry_pathname(in_entry),
                        archive_entry_stat(in_entry)))
                        continue;
                if (excluded(bsdtar, archive_entry_pathname(in_entry)))
                        continue;
                if (bsdtar->option_interactive &&
                    !yes("copy '%s'", archive_entry_pathname(in_entry)))
                        continue;
                if (bsdtar->verbose)
                        safe_fprintf(stderr, "a %s",
                            archive_entry_pathname(in_entry));
                /* XXX handle/report errors XXX */
                if (archive_write_header(a, in_entry)) {
                        bsdtar_warnc(bsdtar, 0, "%s",
                            archive_error_string(a));
                        bsdtar->return_value = 1;
                        return (-1);
                }
                bytes_read = archive_read_data(ina, buff, sizeof(buff));
                while (bytes_read > 0) {
                        bytes_written =
                            archive_write_data(a, buff, bytes_read);
                        if (bytes_written < bytes_read) {
                                bsdtar_warnc(bsdtar, archive_errno(a), "%s",
                                    archive_error_string(a));
                                return (-1);
                        }
                        bytes_read =
                            archive_read_data(ina, buff, sizeof(buff));
                }
                if (bsdtar->verbose)
                        fprintf(stderr, "\n");

        }
        if (archive_errno(ina)) {
                bsdtar_warnc(bsdtar, 0, "Error reading archive %s: %s",
                    filename, archive_error_string(ina));
                bsdtar->return_value = 1;
        }
        archive_read_finish(ina);

        /* Note: If we got here, we saw no write errors, so return success. */
        return (0);
}

/*
 * Add the file or dir hierarchy named by 'path' to the archive
 */
static void
write_hierarchy(struct bsdtar *bsdtar, struct archive *a, const char *path)
{
        struct tree *tree;
        char symlink_mode = bsdtar->symlink_mode;
        dev_t first_dev = 0;
        int dev_recorded = 0;
        int tree_ret;
#ifdef __linux
        int      fd, r;
        unsigned long fflags;
#endif

        tree = tree_open(path);

        if (!tree) {
                bsdtar_warnc(bsdtar, errno, "%s: Cannot open", path);
                bsdtar->return_value = 1;
                return;
        }

        while ((tree_ret = tree_next(tree))) {
                const char *name = tree_current_path(tree);
                const struct stat *st = NULL, *lst = NULL;
                int descend;

                if (tree_ret == TREE_ERROR_DIR)
                        bsdtar_warnc(bsdtar, errno, "%s: Couldn't visit directory", name);
                if (tree_ret != TREE_REGULAR)
                        continue;
                lst = tree_current_lstat(tree);
                if (lst == NULL) {
                        /* Couldn't lstat(); must not exist. */
                        bsdtar_warnc(bsdtar, errno, "%s: Cannot stat", path);
                        bsdtar->return_value = 1;
                        continue;
                }
                if (S_ISLNK(lst->st_mode))
                        st = tree_current_stat(tree);
                /* Default: descend into any dir or symlink to dir. */
                /* We'll adjust this later on. */
                descend = 0;
                if ((st != NULL) && S_ISDIR(st->st_mode))
                        descend = 1;
                if ((lst != NULL) && S_ISDIR(lst->st_mode))
                        descend = 1;

                /*
                 * If user has asked us not to cross mount points,
                 * then don't descend into into a dir on a different
                 * device.
                 */
                if (!dev_recorded) {
                        first_dev = lst->st_dev;
                        dev_recorded = 1;
                }
                if (bsdtar->option_dont_traverse_mounts) {
                        if (lst != NULL && lst->st_dev != first_dev)
                                descend = 0;
                }

                /*
                 * If this file/dir is flagged "nodump" and we're
                 * honoring such flags, skip this file/dir.
                 */
#ifdef HAVE_CHFLAGS
                if (bsdtar->option_honor_nodump &&
                    (lst->st_flags & UF_NODUMP))
                        continue;
#endif

#ifdef __linux
                /*
                 * Linux has a nodump flag too but to read it
                 * we have to open() the file/dir and do an ioctl on it...
                 */
                if (bsdtar->option_honor_nodump &&
                    ((fd = open(name, O_RDONLY|O_NONBLOCK)) >= 0) &&
                    ((r = ioctl(fd, EXT2_IOC_GETFLAGS, &fflags)),
                        close(fd), r) >= 0 &&
                    (fflags & EXT2_NODUMP_FL))
                        continue;
#endif

                /*
                 * If this file/dir is excluded by a filename
                 * pattern, skip it.
                 */
                if (excluded(bsdtar, name))
                        continue;

                /*
                 * If the user vetoes this file/directory, skip it.
                 */
                if (bsdtar->option_interactive &&
                    !yes("add '%s'", name))
                        continue;

                /*
                 * If this is a dir, decide whether or not to recurse.
                 */
                if (bsdtar->option_no_subdirs)
                        descend = 0;

                /*
                 * Distinguish 'L'/'P'/'H' symlink following.
                 */
                switch(symlink_mode) {
                case 'H':
                        /* 'H': After the first item, rest like 'P'. */
                        symlink_mode = 'P';
                        /* 'H': First item (from command line) like 'L'. */
                        /* FALLTHROUGH */
                case 'L':
                        /* 'L': Do descend through a symlink to dir. */
                        /* 'L': Archive symlink to file as file. */
                        lst = tree_current_stat(tree);
                        /* If stat fails, we have a broken symlink;
                         * in that case, archive the link as such. */
                        if (lst == NULL)
                                lst = tree_current_lstat(tree);
                        break;
                default:
                        /* 'P': Don't descend through a symlink to dir. */
                        if (!S_ISDIR(lst->st_mode))
                                descend = 0;
                        /* 'P': Archive symlink to file as symlink. */
                        /* lst = tree_current_lstat(tree); */
                        break;
                }

                if (descend)
                        tree_descend(tree);

                /*
                 * Write the entry.  Note that write_entry() handles
                 * pathname editing and newness testing.
                 */
                write_entry(bsdtar, a, lst, name,
                    tree_current_pathlen(tree),
                    tree_current_access_path(tree));
        }
        tree_close(tree);
}

/*
 * Add a single filesystem object to the archive.
 */
static void
write_entry(struct bsdtar *bsdtar, struct archive *a, const struct stat *st,
    const char *pathname, unsigned pathlen, const char *accpath)
{
        struct archive_entry    *entry;
        int                      e;
        int                      fd;
#ifdef __linux
        int                      r;
        unsigned long            stflags;
#endif
        static char              linkbuffer[PATH_MAX+1];

        (void)pathlen; /* UNUSED */

        fd = -1;
        entry = archive_entry_new();

        archive_entry_set_pathname(entry, pathname);

        /*
         * Rewrite the pathname to be archived.  If rewrite
         * fails, skip the entry.
         */
        if (edit_pathname(bsdtar, entry))
                goto abort;

        /*
         * In -u mode, check that the file is newer than what's
         * already in the archive; in all modes, obey --newerXXX flags.
         */
        if (!new_enough(bsdtar, archive_entry_pathname(entry), st))
                goto abort;

        if (!S_ISDIR(st->st_mode) && (st->st_nlink > 1))
                lookup_hardlink(bsdtar, entry, st);

        /* Display entry as we process it. This format is required by SUSv2. */
        if (bsdtar->verbose)
                safe_fprintf(stderr, "a %s", archive_entry_pathname(entry));

        /* Read symbolic link information. */
        if ((st->st_mode & S_IFMT) == S_IFLNK) {
                int lnklen;

                lnklen = readlink(accpath, linkbuffer, PATH_MAX);
                if (lnklen < 0) {
                        if (!bsdtar->verbose)
                                bsdtar_warnc(bsdtar, errno,
                                    "%s: Couldn't read symbolic link",
                                    pathname);
                        else
                                safe_fprintf(stderr,
                                    ": Couldn't read symbolic link: %s",
                                    strerror(errno));
                        goto cleanup;
                }
                linkbuffer[lnklen] = 0;
                archive_entry_set_symlink(entry, linkbuffer);
        }

        /* Look up username and group name. */
        archive_entry_set_uname(entry, lookup_uname(bsdtar, st->st_uid));
        archive_entry_set_gname(entry, lookup_gname(bsdtar, st->st_gid));

#ifdef HAVE_CHFLAGS
        if (st->st_flags != 0)
                archive_entry_set_fflags(entry, st->st_flags, 0);
#endif

#ifdef __linux
        if ((S_ISREG(st->st_mode) || S_ISDIR(st->st_mode)) &&
            ((fd = open(accpath, O_RDONLY|O_NONBLOCK)) >= 0) &&
            ((r = ioctl(fd, EXT2_IOC_GETFLAGS, &stflags)), close(fd), (fd = -1), r) >= 0 &&
            stflags) {
                archive_entry_set_fflags(entry, stflags, 0);
        }
#endif

        archive_entry_copy_stat(entry, st);
        setup_acls(bsdtar, entry, accpath);
        setup_xattrs(bsdtar, entry, accpath);

        /*
         * If it's a regular file (and non-zero in size) make sure we
         * can open it before we start to write.  In particular, note
         * that we can always archive a zero-length file, even if we
         * can't read it.
         */
        if (S_ISREG(st->st_mode) && st->st_size > 0) {
                fd = open(accpath, O_RDONLY);
                if (fd < 0) {
                        if (!bsdtar->verbose)
                                bsdtar_warnc(bsdtar, errno, "%s: could not open file", pathname);
                        else
                                fprintf(stderr, ": %s", strerror(errno));
                        goto cleanup;
                }
        }

        /* Non-regular files get archived with zero size. */
        if (!S_ISREG(st->st_mode))
                archive_entry_set_size(entry, 0);

        e = archive_write_header(a, entry);
        if (e != ARCHIVE_OK) {
                if (!bsdtar->verbose)
                        bsdtar_warnc(bsdtar, 0, "%s: %s", pathname,
                            archive_error_string(a));
                else
                        fprintf(stderr, ": %s", archive_error_string(a));
        }

        if (e == ARCHIVE_FATAL)
                exit(1);

        /*
         * If we opened a file earlier, write it out now.  Note that
         * the format handler might have reset the size field to zero
         * to inform us that the archive body won't get stored.  In
         * that case, just skip the write.
         */
        if (e >= ARCHIVE_WARN && fd >= 0 && archive_entry_size(entry) > 0)
                if (write_file_data(bsdtar, a, fd))
                        exit(1);

cleanup:
        if (bsdtar->verbose)
                fprintf(stderr, "\n");

abort:
        if (fd >= 0)
                close(fd);

        if (entry != NULL)
                archive_entry_free(entry);
}


/* Helper function to copy file to archive, with stack-allocated buffer. */
static int
write_file_data(struct bsdtar *bsdtar, struct archive *a, int fd)
{
        char    buff[64*1024];
        ssize_t bytes_read;
        ssize_t bytes_written;

        /* XXX TODO: Allocate buffer on heap and store pointer to
         * it in bsdtar structure; arrange cleanup as well. XXX */

        bytes_read = read(fd, buff, sizeof(buff));
        while (bytes_read > 0) {
                bytes_written = archive_write_data(a, buff, bytes_read);
                if (bytes_written < 0) {
                        /* Write failed; this is bad */
                        bsdtar_warnc(bsdtar, 0, "%s", archive_error_string(a));
                        return (-1);
                }
                if (bytes_written < bytes_read) {
                        /* Write was truncated; warn but continue. */
                        bsdtar_warnc(bsdtar, 0,
                            "Truncated write; file may have grown while being archived.");
                        return (0);
                }
                bytes_read = read(fd, buff, sizeof(buff));
        }
        return 0;
}


static void
create_cleanup(struct bsdtar *bsdtar)
{
        /* Free inode->pathname map used for hardlink detection. */
        if (bsdtar->links_cache != NULL) {
                free_buckets(bsdtar, bsdtar->links_cache);
                free(bsdtar->links_cache);
                bsdtar->links_cache = NULL;
        }

        free_cache(bsdtar->uname_cache);
        bsdtar->uname_cache = NULL;
        free_cache(bsdtar->gname_cache);
        bsdtar->gname_cache = NULL;
}


static void
free_buckets(struct bsdtar *bsdtar, struct links_cache *links_cache)
{
        size_t i;

        if (links_cache->buckets == NULL)
                return;

        for (i = 0; i < links_cache->number_buckets; i++) {
                while (links_cache->buckets[i] != NULL) {
                        struct links_entry *lp = links_cache->buckets[i]->next;
                        if (bsdtar->option_warn_links)
                                bsdtar_warnc(bsdtar, 0, "Missing links to %s",
                                    links_cache->buckets[i]->name);
                        if (links_cache->buckets[i]->name != NULL)
                                free(links_cache->buckets[i]->name);
                        free(links_cache->buckets[i]);
                        links_cache->buckets[i] = lp;
                }
        }
        free(links_cache->buckets);
        links_cache->buckets = NULL;
}

static void
lookup_hardlink(struct bsdtar *bsdtar, struct archive_entry *entry,
    const struct stat *st)
{
        struct links_cache      *links_cache;
        struct links_entry      *le, **new_buckets;
        int                      hash;
        size_t                   i, new_size;

        /* If necessary, initialize the links cache. */
        links_cache = bsdtar->links_cache;
        if (links_cache == NULL) {
                bsdtar->links_cache = malloc(sizeof(struct links_cache));
                if (bsdtar->links_cache == NULL)
                        bsdtar_errc(bsdtar, 1, ENOMEM,
                            "No memory for hardlink detection.");
                links_cache = bsdtar->links_cache;
                memset(links_cache, 0, sizeof(struct links_cache));
                links_cache->number_buckets = links_cache_initial_size;
                links_cache->buckets = malloc(links_cache->number_buckets *
                    sizeof(links_cache->buckets[0]));
                if (links_cache->buckets == NULL) {
                        bsdtar_errc(bsdtar, 1, ENOMEM,
                            "No memory for hardlink detection.");
                }
                for (i = 0; i < links_cache->number_buckets; i++)
                        links_cache->buckets[i] = NULL;
        }

        /* If the links cache overflowed and got flushed, don't bother. */
        if (links_cache->buckets == NULL)
                return;

        /* If the links cache is getting too full, enlarge the hash table. */
        if (links_cache->number_entries > links_cache->number_buckets * 2)
        {
                new_size = links_cache->number_buckets * 2;
                new_buckets = malloc(new_size * sizeof(struct links_entry *));

                if (new_buckets != NULL) {
                        memset(new_buckets, 0,
                            new_size * sizeof(struct links_entry *));
                        for (i = 0; i < links_cache->number_buckets; i++) {
                                while (links_cache->buckets[i] != NULL) {
                                        /* Remove entry from old bucket. */
                                        le = links_cache->buckets[i];
                                        links_cache->buckets[i] = le->next;

                                        /* Add entry to new bucket. */
                                        hash = (le->dev ^ le->ino) % new_size;

                                        if (new_buckets[hash] != NULL)
                                                new_buckets[hash]->previous =
                                                    le;
                                        le->next = new_buckets[hash];
                                        le->previous = NULL;
                                        new_buckets[hash] = le;
                                }
                        }
                        free(links_cache->buckets);
                        links_cache->buckets = new_buckets;
                        links_cache->number_buckets = new_size;
                } else {
                        free_buckets(bsdtar, links_cache);
                        bsdtar_warnc(bsdtar, ENOMEM,
                            "No more memory for recording hard links");
                        bsdtar_warnc(bsdtar, 0,
                            "Remaining links will be dumped as full files");
                }
        }

        /* Try to locate this entry in the links cache. */
        hash = ( st->st_dev ^ st->st_ino ) % links_cache->number_buckets;
        for (le = links_cache->buckets[hash]; le != NULL; le = le->next) {
                if (le->dev == st->st_dev && le->ino == st->st_ino) {
                        archive_entry_copy_hardlink(entry, le->name);

                        /*
                         * Decrement link count each time and release
                         * the entry if it hits zero.  This saves
                         * memory and is necessary for proper -l
                         * implementation.
                         */
                        if (--le->links <= 0) {
                                if (le->previous != NULL)
                                        le->previous->next = le->next;
                                if (le->next != NULL)
                                        le->next->previous = le->previous;
                                if (le->name != NULL)
                                        free(le->name);
                                if (links_cache->buckets[hash] == le)
                                        links_cache->buckets[hash] = le->next;
                                links_cache->number_entries--;
                                free(le);
                        }

                        return;
                }
        }

        /* Add this entry to the links cache. */
        le = malloc(sizeof(struct links_entry));
        if (le != NULL)
                le->name = strdup(archive_entry_pathname(entry));
        if ((le == NULL) || (le->name == NULL)) {
                free_buckets(bsdtar, links_cache);
                bsdtar_warnc(bsdtar, ENOMEM,
                    "No more memory for recording hard links");
                bsdtar_warnc(bsdtar, 0,
                    "Remaining hard links will be dumped as full files");
                if (le != NULL)
                        free(le);
                return;
        }
        if (links_cache->buckets[hash] != NULL)
                links_cache->buckets[hash]->previous = le;
        links_cache->number_entries++;
        le->next = links_cache->buckets[hash];
        le->previous = NULL;
        links_cache->buckets[hash] = le;
        le->dev = st->st_dev;
        le->ino = st->st_ino;
        le->links = st->st_nlink - 1;
}

#ifdef HAVE_POSIX_ACL
static void             setup_acl(struct bsdtar *bsdtar,
                             struct archive_entry *entry, const char *accpath,
                             int acl_type, int archive_entry_acl_type);

static void
setup_acls(struct bsdtar *bsdtar, struct archive_entry *entry,
    const char *accpath)
{
        archive_entry_acl_clear(entry);

        setup_acl(bsdtar, entry, accpath,
            ACL_TYPE_ACCESS, ARCHIVE_ENTRY_ACL_TYPE_ACCESS);
        /* Only directories can have default ACLs. */
        if (S_ISDIR(archive_entry_mode(entry)))
                setup_acl(bsdtar, entry, accpath,
                    ACL_TYPE_DEFAULT, ARCHIVE_ENTRY_ACL_TYPE_DEFAULT);
}

static void
setup_acl(struct bsdtar *bsdtar, struct archive_entry *entry,
    const char *accpath, int acl_type, int archive_entry_acl_type)
{
        acl_t            acl;
        acl_tag_t        acl_tag;
        acl_entry_t      acl_entry;
        acl_permset_t    acl_permset;
        int              s, ae_id, ae_tag, ae_perm;
        const char      *ae_name;

        /* Retrieve access ACL from file. */
        acl = acl_get_file(accpath, acl_type);
        if (acl != NULL) {
                s = acl_get_entry(acl, ACL_FIRST_ENTRY, &acl_entry);
                while (s == 1) {
                        ae_id = -1;
                        ae_name = NULL;

                        acl_get_tag_type(acl_entry, &acl_tag);
                        if (acl_tag == ACL_USER) {
                                ae_id = (int)*(uid_t *)acl_get_qualifier(acl_entry);
                                ae_name = lookup_uname(bsdtar, ae_id);
                                ae_tag = ARCHIVE_ENTRY_ACL_USER;
                        } else if (acl_tag == ACL_GROUP) {
                                ae_id = (int)*(gid_t *)acl_get_qualifier(acl_entry);
                                ae_name = lookup_gname(bsdtar, ae_id);
                                ae_tag = ARCHIVE_ENTRY_ACL_GROUP;
                        } else if (acl_tag == ACL_MASK) {
                                ae_tag = ARCHIVE_ENTRY_ACL_MASK;
                        } else if (acl_tag == ACL_USER_OBJ) {
                                ae_tag = ARCHIVE_ENTRY_ACL_USER_OBJ;
                        } else if (acl_tag == ACL_GROUP_OBJ) {
                                ae_tag = ARCHIVE_ENTRY_ACL_GROUP_OBJ;
                        } else if (acl_tag == ACL_OTHER) {
                                ae_tag = ARCHIVE_ENTRY_ACL_OTHER;
                        } else {
                                /* Skip types that libarchive can't support. */
                                continue;
                        }

                        acl_get_permset(acl_entry, &acl_permset);
                        ae_perm = 0;
                        /*
                         * acl_get_perm() is spelled differently on different
                         * platforms; see bsdtar_platform.h for details.
                         */
                        if (ACL_GET_PERM(acl_permset, ACL_EXECUTE))
                                ae_perm |= ARCHIVE_ENTRY_ACL_EXECUTE;
                        if (ACL_GET_PERM(acl_permset, ACL_READ))
                                ae_perm |= ARCHIVE_ENTRY_ACL_READ;
                        if (ACL_GET_PERM(acl_permset, ACL_WRITE))
                                ae_perm |= ARCHIVE_ENTRY_ACL_WRITE;

                        archive_entry_acl_add_entry(entry,
                            archive_entry_acl_type, ae_perm, ae_tag,
                            ae_id, ae_name);

                        s = acl_get_entry(acl, ACL_NEXT_ENTRY, &acl_entry);
                }
                acl_free(acl);
        }
}
#else
static void
setup_acls(struct bsdtar *bsdtar, struct archive_entry *entry,
    const char *accpath)
{
        (void)bsdtar;
        (void)entry;
        (void)accpath;
}
#endif

#if HAVE_LISTXATTR && HAVE_LLISTXATTR && HAVE_GETXATTR && HAVE_LGETXATTR

static void
setup_xattr(struct bsdtar *bsdtar, struct archive_entry *entry,
    const char *accpath, const char *name)
{
        size_t size;
        void *value = NULL;
        char symlink_mode = bsdtar->symlink_mode;

        if (symlink_mode == 'H')
                size = getxattr(accpath, name, NULL, 0);
        else
                size = lgetxattr(accpath, name, NULL, 0);

        if (size == -1) {
                bsdtar_warnc(bsdtar, errno, "Couldn't get extended attribute");
                return;
        }

        if (size > 0 && (value = malloc(size)) == NULL) {
                bsdtar_errc(bsdtar, 1, errno, "Out of memory");
                return;
        }

        if (symlink_mode == 'H')
                size = getxattr(accpath, name, value, size);
        else
                size = lgetxattr(accpath, name, value, size);

        if (size == -1) {
                bsdtar_warnc(bsdtar, errno, "Couldn't get extended attribute");
                return;
        }

        archive_entry_xattr_add_entry(entry, name, value, size);

        free(value);
}

/*
 * Linux extended attribute support
 */
static void
setup_xattrs(struct bsdtar *bsdtar, struct archive_entry *entry,
    const char *accpath)
{
        char *list, *p;
        size_t list_size;
        char symlink_mode = bsdtar->symlink_mode;

        if (symlink_mode == 'H')
                list_size = listxattr(accpath, NULL, 0);
        else
                list_size = llistxattr(accpath, NULL, 0);

        if (list_size == -1) {
                bsdtar_warnc(bsdtar, errno,
                        "Couldn't list extended attributes");
                return;
        } else if (list_size == 0)
                return;

        if ((list = malloc(list_size)) == NULL) {
                bsdtar_errc(bsdtar, 1, errno, "Out of memory");
                return;
        }

        if (symlink_mode == 'H')
                list_size = listxattr(accpath, list, list_size);
        else
                list_size = llistxattr(accpath, list, list_size);

        if (list_size == -1) {
                bsdtar_warnc(bsdtar, errno,
                        "Couldn't list extended attributes");
                free(list);
                return;
        }

        for (p = list; (p - list) < list_size; p += strlen(p) + 1) {
                if (strncmp(p, "system.", 7) == 0 ||
                                strncmp(p, "xfsroot.", 8) == 0)
                        continue;

                setup_xattr(bsdtar, entry, accpath, p);
        }

        free(list);
}

#else

/*
 * Generic (stub) extended attribute support.
 */
static void
setup_xattrs(struct bsdtar *bsdtar, struct archive_entry *entry,
    const char *accpath)
{
        (void)bsdtar; /* UNUSED */
        (void)entry; /* UNUSED */
        (void)accpath; /* UNUSED */
}

#endif

static void
free_cache(struct name_cache *cache)
{
        size_t i;

        if (cache != NULL) {
                for (i = 0; i < cache->size; i++) {
                        if (cache->cache[i].name != NULL &&
                            cache->cache[i].name != NO_NAME)
                                free((void *)(uintptr_t)cache->cache[i].name);
                }
                free(cache);
        }
}

/*
 * Lookup uid/gid from uname/gname, return NULL if no match.
 */
static const char *
lookup_name(struct bsdtar *bsdtar, struct name_cache **name_cache_variable,
    int (*lookup_fn)(struct bsdtar *, const char **, id_t), id_t id)
{
        struct name_cache       *cache;
        const char *name;
        int slot;


        if (*name_cache_variable == NULL) {
                *name_cache_variable = malloc(sizeof(struct name_cache));
                if (*name_cache_variable == NULL)
                        bsdtar_errc(bsdtar, 1, ENOMEM, "No more memory");
                memset(*name_cache_variable, 0, sizeof(struct name_cache));
                (*name_cache_variable)->size = name_cache_size;
        }

        cache = *name_cache_variable;
        cache->probes++;

        slot = id % cache->size;
        if (cache->cache[slot].name != NULL) {
                if (cache->cache[slot].id == id) {
                        cache->hits++;
                        if (cache->cache[slot].name == NO_NAME)
                                return (NULL);
                        return (cache->cache[slot].name);
                }
                if (cache->cache[slot].name != NO_NAME)
                        free((void *)(uintptr_t)cache->cache[slot].name);
                cache->cache[slot].name = NULL;
        }

        if (lookup_fn(bsdtar, &name, id) == 0) {
                if (name == NULL || name[0] == '\0') {
                        /* Cache the negative response. */
                        cache->cache[slot].name = NO_NAME;
                        cache->cache[slot].id = id;
                } else {
                        cache->cache[slot].name = strdup(name);
                        if (cache->cache[slot].name != NULL) {
                                cache->cache[slot].id = id;
                                return (cache->cache[slot].name);
                        }
                        /*
                         * Conveniently, NULL marks an empty slot, so
                         * if the strdup() fails, we've just failed to
                         * cache it.  No recovery necessary.
                         */
                }
        }
        return (NULL);
}

static const char *
lookup_uname(struct bsdtar *bsdtar, uid_t uid)
{
        return (lookup_name(bsdtar, &bsdtar->uname_cache,
                    &lookup_uname_helper, (id_t)uid));
}

static int
lookup_uname_helper(struct bsdtar *bsdtar, const char **name, id_t id)
{
        struct passwd   *pwent;

        (void)bsdtar; /* UNUSED */

        errno = 0;
        pwent = getpwuid((uid_t)id);
        if (pwent == NULL) {
                *name = NULL;
                if (errno != 0)
                        bsdtar_warnc(bsdtar, errno, "getpwuid(%d) failed", id);
                return (errno);
        }

        *name = pwent->pw_name;
        return (0);
}

static const char *
lookup_gname(struct bsdtar *bsdtar, gid_t gid)
{
        return (lookup_name(bsdtar, &bsdtar->gname_cache,
                    &lookup_gname_helper, (id_t)gid));
}

static int
lookup_gname_helper(struct bsdtar *bsdtar, const char **name, id_t id)
{
        struct group    *grent;

        (void)bsdtar; /* UNUSED */

        errno = 0;
        grent = getgrgid((gid_t)id);
        if (grent == NULL) {
                *name = NULL;
                if (errno != 0)
                        bsdtar_warnc(bsdtar, errno, "getgrgid(%d) failed", id);
                return (errno);
        }

        *name = grent->gr_name;
        return (0);
}

/*
 * Test if the specified file is new enough to include in the archive.
 */
int
new_enough(struct bsdtar *bsdtar, const char *path, const struct stat *st)
{
        struct archive_dir_entry *p;

        /*
         * If this file/dir is excluded by a time comparison, skip it.
         */
        if (bsdtar->newer_ctime_sec > 0) {
                if (st->st_ctime < bsdtar->newer_ctime_sec)
                        return (0); /* Too old, skip it. */
                if (st->st_ctime == bsdtar->newer_ctime_sec
                    && ARCHIVE_STAT_CTIME_NANOS(st)
                    <= bsdtar->newer_ctime_nsec)
                        return (0); /* Too old, skip it. */
        }
        if (bsdtar->newer_mtime_sec > 0) {
                if (st->st_mtime < bsdtar->newer_mtime_sec)
                        return (0); /* Too old, skip it. */
                if (st->st_mtime == bsdtar->newer_mtime_sec
                    && ARCHIVE_STAT_MTIME_NANOS(st)
                    <= bsdtar->newer_mtime_nsec)
                        return (0); /* Too old, skip it. */
        }

        /*
         * In -u mode, we only write an entry if it's newer than
         * what was already in the archive.
         */
        if (bsdtar->archive_dir != NULL &&
            bsdtar->archive_dir->head != NULL) {
                for (p = bsdtar->archive_dir->head; p != NULL; p = p->next) {
                        if (pathcmp(path, p->name)==0)
                                return (p->mtime_sec < st->st_mtime ||
                                    (p->mtime_sec == st->st_mtime &&
                                        p->mtime_nsec
                                        < ARCHIVE_STAT_MTIME_NANOS(st)));
                }
        }

        /* If the file wasn't rejected, include it. */
        return (1);
}

/*
 * Add an entry to the dir list for 'u' mode.
 *
 * XXX TODO: Make this fast.
 */
static void
add_dir_list(struct bsdtar *bsdtar, const char *path,
    time_t mtime_sec, int mtime_nsec)
{
        struct archive_dir_entry        *p;

        /*
         * Search entire list to see if this file has appeared before.
         * If it has, override the timestamp data.
         */
        p = bsdtar->archive_dir->head;
        while (p != NULL) {
                if (strcmp(path, p->name)==0) {
                        p->mtime_sec = mtime_sec;
                        p->mtime_nsec = mtime_nsec;
                        return;
                }
                p = p->next;
        }

        p = malloc(sizeof(*p));
        if (p == NULL)
                bsdtar_errc(bsdtar, 1, ENOMEM, "Can't read archive directory");

        p->name = strdup(path);
        if (p->name == NULL)
                bsdtar_errc(bsdtar, 1, ENOMEM, "Can't read archive directory");
        p->mtime_sec = mtime_sec;
        p->mtime_nsec = mtime_nsec;
        p->next = NULL;
        if (bsdtar->archive_dir->tail == NULL) {
                bsdtar->archive_dir->head = bsdtar->archive_dir->tail = p;
        } else {
                bsdtar->archive_dir->tail->next = p;
                bsdtar->archive_dir->tail = p;
        }
}

void
test_for_append(struct bsdtar *bsdtar)
{
        struct stat s;

        if (*bsdtar->argv == NULL)
                bsdtar_errc(bsdtar, 1, 0, "no files or directories specified");
        if (bsdtar->filename == NULL)
                bsdtar_errc(bsdtar, 1, 0, "Cannot append to stdout.");

        if (bsdtar->create_compression != 0)
                bsdtar_errc(bsdtar, 1, 0,
                    "Cannot append to %s with compression", bsdtar->filename);

        if (stat(bsdtar->filename, &s) != 0)
                return;

        if (!S_ISREG(s.st_mode))
                bsdtar_errc(bsdtar, 1, 0,
                    "Cannot append to %s: not a regular file.",
                    bsdtar->filename);
}