Remove building with NOCRYPTO option

[minix3.git] / external / bsd / libarchive / dist / 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 1.79 2008/11/27 05:49:52 kientzle Exp $");

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.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_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_GRP_H
#include <grp.h>
#endif
#ifdef HAVE_IO_H
#include <io.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.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__)
/* This header exists but is broken on Cygwin. */
#include <ext2fs/ext2_fs.h>
#endif
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif
#ifdef HAVE_STDINT_H
#include <stdint.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 "err.h"
#include "line_reader.h"
#include "tree.h"

/* Size of buffer for holding file data prior to writing. */
#define FILEDATABUFLEN  65536

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

#ifndef O_BINARY
#define O_BINARY 0
#endif

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

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 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 *,
                             struct archive *ina);
static int               append_archive_filename(struct bsdtar *,
                             struct archive *, const char *fname);
static void              archive_names_from_file(struct bsdtar *bsdtar,
                             struct archive *a);
static int               copy_file_data(struct bsdtar *, struct archive *a,
                             struct archive *ina, struct archive_entry *);
static int               new_enough(struct bsdtar *, const char *path,
                             const struct stat *);
static void              report_write(struct bsdtar *, struct archive *,
                             struct archive_entry *, int64_t progress);
static void              test_for_append(struct bsdtar *);
static void              write_archive(struct archive *, struct bsdtar *);
static void              write_entry_backend(struct bsdtar *, struct archive *,
                             struct archive_entry *);
static int               write_file_data(struct bsdtar *, struct archive *,
                             struct archive_entry *, int fd);
static void              write_hierarchy(struct bsdtar *, struct archive *,
                             const char *);

#if defined(_WIN32) && !defined(__CYGWIN__)
/* Not a full lseek() emulation, but enough for our needs here. */
static int
seek_file(int fd, int64_t offset, int whence)
{
        LARGE_INTEGER distance;
        (void)whence; /* UNUSED */
        distance.QuadPart = offset;
        return (SetFilePointerEx((HANDLE)_get_osfhandle(fd),
                distance, NULL, FILE_BEGIN) ? 1 : -1);
}
#define open _open
#define close _close
#define read _read
#define lseek seek_file
#endif

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

        if (*bsdtar->argv == NULL && bsdtar->names_from_file == NULL)
                lafe_errc(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();
        }

        /*
         * 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);

        if (bsdtar->compress_program) {
                archive_write_set_compression_program(a, bsdtar->compress_program);
        } else {
                switch (bsdtar->create_compression) {
                case 0:
                        r = archive_write_set_compression_none(a);
                        break;
                case 'j': case 'y':
                        r = archive_write_set_compression_bzip2(a);
                        break;
                case 'J':
                        r = archive_write_set_compression_xz(a);
                        break;
                case OPTION_LZMA:
                        r = archive_write_set_compression_lzma(a);
                        break;
                case 'z':
                        r = archive_write_set_compression_gzip(a);
                        break;
                case 'Z':
                        r = archive_write_set_compression_compress(a);
                        break;
                default:
                        lafe_errc(1, 0,
                            "Unrecognized compression option -%c",
                            bsdtar->create_compression);
                }
                if (r != ARCHIVE_OK) {
                        lafe_errc(1, 0,
                            "Unsupported compression option -%c",
                            bsdtar->create_compression);
                }
        }

        if (ARCHIVE_OK != archive_write_set_options(a, bsdtar->option_options))
                lafe_errc(1, 0, "%s", archive_error_string(a));
        if (ARCHIVE_OK != archive_write_open_file(a, bsdtar->filename))
                lafe_errc(1, 0, "%s", archive_error_string(a));
        write_archive(a, bsdtar);
}

/*
 * Same as 'c', except we only support tar or empty formats in
 * uncompressed files on disk.
 */
void
tar_mode_r(struct bsdtar *bsdtar)
{
        int64_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;

#if defined(__BORLANDC__)
        bsdtar->fd = open(bsdtar->filename, O_RDWR | O_CREAT | O_BINARY);
#else
        bsdtar->fd = open(bsdtar->filename, O_RDWR | O_CREAT | O_BINARY, 0666);
#endif
        if (bsdtar->fd < 0)
                lafe_errc(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)
                lafe_errc(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);
                        lafe_errc(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) {
                        lafe_errc(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);
        }
        if (lseek(bsdtar->fd, end_offset, SEEK_SET) < 0)
                lafe_errc(1, errno, "Could not seek to archive end");
        if (ARCHIVE_OK != archive_write_set_options(a, bsdtar->option_options))
                lafe_errc(1, 0, "%s", archive_error_string(a));
        if (ARCHIVE_OK != archive_write_open_fd(a, bsdtar->fd))
                lafe_errc(1, 0, "%s", archive_error_string(a));

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

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

void
tar_mode_u(struct bsdtar *bsdtar)
{
        int64_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 | O_BINARY);
        if (bsdtar->fd < 0)
                lafe_errc(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) {
                lafe_errc(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);
                        lafe_errc(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);
        if (lseek(bsdtar->fd, end_offset, SEEK_SET) < 0)
                lafe_errc(1, errno, "Could not seek to archive end");
        if (ARCHIVE_OK != archive_write_set_options(a, bsdtar->option_options))
                lafe_errc(1, 0, "%s", archive_error_string(a));
        if (ARCHIVE_OK != archive_write_open_fd(a, bsdtar->fd))
                lafe_errc(1, 0, "%s", archive_error_string(a));

        write_archive(a, bsdtar);

        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;
        struct archive_entry *entry, *sparse_entry;

        /* Allocate a buffer for file data. */
        if ((bsdtar->buff = malloc(FILEDATABUFLEN)) == NULL)
                lafe_errc(1, 0, "cannot allocate memory");

        if ((bsdtar->resolver = archive_entry_linkresolver_new()) == NULL)
                lafe_errc(1, 0, "cannot create link resolver");
        archive_entry_linkresolver_set_strategy(bsdtar->resolver,
            archive_format(a));
        if ((bsdtar->diskreader = archive_read_disk_new()) == NULL)
                lafe_errc(1, 0, "Cannot create read_disk object");
        archive_read_disk_set_standard_lookup(bsdtar->diskreader);

        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) {
                                        lafe_warnc(0, "%s",
                                            "Missing argument for -C");
                                        bsdtar->return_value = 1;
                                        goto cleanup;
                                }
                        }
                        set_chdir(bsdtar, arg);
                } else {
                        if (*arg != '/' && (arg[0] != '@' || arg[1] != '/'))
                                do_chdir(bsdtar); /* Handle a deferred -C */
                        if (*arg == '@') {
                                if (append_archive_filename(bsdtar, a,
                                    arg + 1) != 0)
                                        break;
                        } else
                                write_hierarchy(bsdtar, a, arg);
                }
                bsdtar->argv++;
        }

        entry = NULL;
        archive_entry_linkify(bsdtar->resolver, &entry, &sparse_entry);
        while (entry != NULL) {
                write_entry_backend(bsdtar, a, entry);
                archive_entry_free(entry);
                entry = NULL;
                archive_entry_linkify(bsdtar->resolver, &entry, &sparse_entry);
        }

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

cleanup:
        /* Free file data buffer. */
        free(bsdtar->buff);
        archive_entry_linkresolver_free(bsdtar->resolver);
        bsdtar->resolver = NULL;
        archive_read_finish(bsdtar->diskreader);
        bsdtar->diskreader = NULL;

        if (bsdtar->option_totals) {
                fprintf(stderr, "Total bytes written: %s\n",
                    tar_i64toa(archive_position_compressed(a)));
        }

        archive_write_finish(a);
}

/*
 * 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.
 */
static void
archive_names_from_file(struct bsdtar *bsdtar, struct archive *a)
{
        struct lafe_line_reader *lr;
        const char *line;

        bsdtar->next_line_is_dir = 0;

        lr = lafe_line_reader(bsdtar->names_from_file, bsdtar->option_null);
        while ((line = lafe_line_reader_next(lr)) != NULL) {
                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, a, line);
                }
        }
        lafe_line_reader_free(lr);
        if (bsdtar->next_line_is_dir)
                lafe_errc(1, errno,
                    "Unexpected end of filename list; "
                    "directory expected after -C");
}

/*
 * 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_filename(struct bsdtar *bsdtar, struct archive *a,
    const char *filename)
{
        struct archive *ina;
        int rc;

        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)) {
                lafe_warnc(0, "%s", archive_error_string(ina));
                bsdtar->return_value = 1;
                return (0);
        }

        rc = append_archive(bsdtar, a, ina);

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

        return (rc);
}

static int
append_archive(struct bsdtar *bsdtar, struct archive *a, struct archive *ina)
{
        struct archive_entry *in_entry;
        int e;

        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 (lafe_excluded(bsdtar->matching, 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));
                if (need_report())
                        report_write(bsdtar, a, in_entry, 0);

                e = archive_write_header(a, in_entry);
                if (e != ARCHIVE_OK) {
                        if (!bsdtar->verbose)
                                lafe_warnc(0, "%s: %s",
                                    archive_entry_pathname(in_entry),
                                    archive_error_string(a));
                        else
                                fprintf(stderr, ": %s", archive_error_string(a));
                }
                if (e == ARCHIVE_FATAL)
                        exit(1);

                if (e >= ARCHIVE_WARN) {
                        if (archive_entry_size(in_entry) == 0)
                                archive_read_data_skip(ina);
                        else if (copy_file_data(bsdtar, a, ina, in_entry))
                                exit(1);
                }

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

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

/* Helper function to copy data between archives. */
static int
copy_file_data(struct bsdtar *bsdtar, struct archive *a,
    struct archive *ina, struct archive_entry *entry)
{
        ssize_t bytes_read;
        ssize_t bytes_written;
        int64_t progress = 0;

        bytes_read = archive_read_data(ina, bsdtar->buff, FILEDATABUFLEN);
        while (bytes_read > 0) {
                if (need_report())
                        report_write(bsdtar, a, entry, progress);

                bytes_written = archive_write_data(a, bsdtar->buff,
                    bytes_read);
                if (bytes_written < bytes_read) {
                        lafe_warnc(0, "%s", archive_error_string(a));
                        return (-1);
                }
                progress += bytes_written;
                bytes_read = archive_read_data(ina, bsdtar->buff,
                    FILEDATABUFLEN);
        }

        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 archive_entry *entry = NULL, *spare_entry = NULL;
        struct tree *tree;
        char symlink_mode = bsdtar->symlink_mode;
        dev_t first_dev = 0;
        int dev_recorded = 0;
        int tree_ret;

        tree = tree_open(path);

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

        while ((tree_ret = tree_next(tree)) != 0) {
                int r;
                const char *name = tree_current_path(tree);
                const struct stat *st = NULL; /* info to use for this entry */
                const struct stat *lst = NULL; /* lstat() information */
                int descend;

                if (tree_ret == TREE_ERROR_FATAL)
                        lafe_errc(1, tree_errno(tree),
                            "%s: Unable to continue traversing directory tree",
                            name);
                if (tree_ret == TREE_ERROR_DIR) {
                        lafe_warnc(errno,
                            "%s: Couldn't visit directory", name);
                        bsdtar->return_value = 1;
                }
                if (tree_ret != TREE_REGULAR)
                        continue;

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

                /*
                 * Get lstat() info from the tree library.
                 */
                lst = tree_current_lstat(tree);
                if (lst == NULL) {
                        /* Couldn't lstat(); must not exist. */
                        lafe_warnc(errno, "%s: Cannot stat", name);
                        /* Return error if files disappear during traverse. */
                        bsdtar->return_value = 1;
                        continue;
                }

                /*
                 * 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. */
                        descend = tree_current_is_dir(tree);
                        /* 'L': Follow symlinks to files. */
                        archive_read_disk_set_symlink_logical(bsdtar->diskreader);
                        /* 'L': Archive symlinks as targets, if we can. */
                        st = tree_current_stat(tree);
                        if (st != NULL)
                                break;
                        /* If stat fails, we have a broken symlink;
                         * in that case, don't follow the link. */
                        /* FALLTHROUGH */
                default:
                        /* 'P': Don't descend through a symlink to dir. */
                        descend = tree_current_is_physical_dir(tree);
                        /* 'P': Don't follow symlinks to files. */
                        archive_read_disk_set_symlink_physical(bsdtar->diskreader);
                        /* 'P': Archive symlinks as symlinks. */
                        st = lst;
                        break;
                }

                /*
                 * Are we about to cross to a new filesystem?
                 */
                if (!dev_recorded) {
                        /* This is the initial file system. */
                        first_dev = lst->st_dev;
                        dev_recorded = 1;
                } else if (lst->st_dev == first_dev) {
                        /* The starting file system is always acceptable. */
                } else if (descend == 0) {
                        /* We're not descending, so no need to check. */
                } else if (bsdtar->option_dont_traverse_mounts) {
                        /* User has asked us not to cross mount points. */
                        descend = 0;
                } else {
                        /* We're prepared to cross a mount point. */

                        /* XXX TODO: check whether this filesystem is
                         * synthetic and/or local.  Add a new
                         * --local-only option to skip non-local
                         * filesystems.  Skip synthetic filesystems
                         * regardless.
                         *
                         * The results should be cached, since
                         * tree.c doesn't usually visit a directory
                         * and the directory contents together.  A simple
                         * move-to-front list should perform quite well.
                         *
                         * This is going to be heavily OS dependent:
                         * FreeBSD's statfs() in conjunction with getvfsbyname()
                         * provides all of this; NetBSD's statvfs() does
                         * most of it; other systems will vary.
                         */
                }

                /*
                 * 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, name, st))
                        continue;

                archive_entry_free(entry);
                entry = archive_entry_new();

                archive_entry_set_pathname(entry, name);
                archive_entry_copy_sourcepath(entry,
                    tree_current_access_path(tree));

                /* Populate the archive_entry with metadata from the disk. */
                /* XXX TODO: Arrange to open a regular file before
                 * calling this so we can pass in an fd and shorten
                 * the race to query metadata.  The linkify dance
                 * makes this more complex than it might sound. */
#if defined(_WIN32) && !defined(__CYGWIN__)
                /* TODO: tree.c uses stat(), which is badly broken
                 * on Windows.  To fix this, we should
                 * deprecate tree_current_stat() and provide a new
                 * call tree_populate_entry(t, entry).  This call
                 * would use stat() internally on POSIX and
                 * GetInfoByFileHandle() internally on Windows.
                 * This would be another step towards a tree-walker
                 * that can be integrated deep into libarchive.
                 * For now, just set st to NULL on Windows;
                 * archive_read_disk_entry_from_file() should
                 * be smart enough to use platform-appropriate
                 * ways to probe file information.
                 */
                st = NULL;
#endif
                r = archive_read_disk_entry_from_file(bsdtar->diskreader,
                    entry, -1, st);
                if (r != ARCHIVE_OK)
                        lafe_warnc(archive_errno(bsdtar->diskreader),
                            "%s", archive_error_string(bsdtar->diskreader));
                if (r < ARCHIVE_WARN)
                        continue;

                /* XXX TODO: Just use flag data from entry; avoid the
                 * duplicate check here. */

                /*
                 * If this file/dir is flagged "nodump" and we're
                 * honoring such flags, skip this file/dir.
                 */
#if defined(HAVE_STRUCT_STAT_ST_FLAGS) && defined(UF_NODUMP)
                /* BSD systems store flags in struct stat */
                if (bsdtar->option_honor_nodump &&
                    (lst->st_flags & UF_NODUMP))
                        continue;
#endif

#if defined(EXT2_IOC_GETFLAGS) && defined(EXT2_NODUMP_FL)
                /* Linux uses ioctl to read flags. */
                if (bsdtar->option_honor_nodump) {
                        int fd = open(name, O_RDONLY | O_NONBLOCK | O_BINARY);
                        if (fd >= 0) {
                                unsigned long fflags;
                                int r = ioctl(fd, EXT2_IOC_GETFLAGS, &fflags);
                                close(fd);
                                if (r >= 0 && (fflags & EXT2_NODUMP_FL))
                                        continue;
                        }
                }
#endif

                /*
                 * If the user vetoes this file/directory, skip it.
                 * We want this to be fairly late; if some other
                 * check would veto this file, we shouldn't bother
                 * the user with it.
                 */
                if (bsdtar->option_interactive &&
                    !yes("add '%s'", name))
                        continue;

                /* Note: if user vetoes, we won't descend. */
                if (descend && !bsdtar->option_no_subdirs)
                        tree_descend(tree);

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

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

                /* Non-regular files get archived with zero size. */
                if (archive_entry_filetype(entry) != AE_IFREG)
                        archive_entry_set_size(entry, 0);

                archive_entry_linkify(bsdtar->resolver, &entry, &spare_entry);

                while (entry != NULL) {
                        write_entry_backend(bsdtar, a, entry);
                        archive_entry_free(entry);
                        entry = spare_entry;
                        spare_entry = NULL;
                }

                if (bsdtar->verbose)
                        fprintf(stderr, "\n");
        }
        archive_entry_free(entry);
        tree_close(tree);
}

/*
 * Backend for write_entry.
 */
static void
write_entry_backend(struct bsdtar *bsdtar, struct archive *a,
    struct archive_entry *entry)
{
        int fd = -1;
        int e;

        if (archive_entry_size(entry) > 0) {
                const char *pathname = archive_entry_sourcepath(entry);
                fd = open(pathname, O_RDONLY | O_BINARY);
                if (fd == -1) {
                        if (!bsdtar->verbose)
                                lafe_warnc(errno,
                                    "%s: could not open file", pathname);
                        else
                                fprintf(stderr, ": %s", strerror(errno));
                        return;
                }
        }

        e = archive_write_header(a, entry);
        if (e != ARCHIVE_OK) {
                if (!bsdtar->verbose)
                        lafe_warnc(0, "%s: %s",
                            archive_entry_pathname(entry),
                            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, entry, fd))
                        exit(1);
        }

        /*
         * If we opened a file, close it now even if there was an error
         * which made us decide not to write the archive body.
         */
        if (fd >= 0)
                close(fd);
}

static void
report_write(struct bsdtar *bsdtar, struct archive *a,
    struct archive_entry *entry, int64_t progress)
{
        uint64_t comp, uncomp;
        if (bsdtar->verbose)
                fprintf(stderr, "\n");
        comp = archive_position_compressed(a);
        uncomp = archive_position_uncompressed(a);
        fprintf(stderr, "In: %d files, %s bytes;",
            archive_file_count(a), tar_i64toa(uncomp));
        fprintf(stderr,
            " Out: %s bytes, compression %d%%\n",
            tar_i64toa(comp), (int)((uncomp - comp) * 100 / uncomp));
        /* Can't have two calls to tar_i64toa() pending, so split the output. */
        safe_fprintf(stderr, "Current: %s (%s",
            archive_entry_pathname(entry),
            tar_i64toa(progress));
        fprintf(stderr, "/%s bytes)\n",
            tar_i64toa(archive_entry_size(entry)));
}


/* Helper function to copy file to archive. */
static int
write_file_data(struct bsdtar *bsdtar, struct archive *a,
    struct archive_entry *entry, int fd)
{
        ssize_t bytes_read;
        ssize_t bytes_written;
        int64_t progress = 0;

        bytes_read = read(fd, bsdtar->buff, FILEDATABUFLEN);
        while (bytes_read > 0) {
                if (need_report())
                        report_write(bsdtar, a, entry, progress);

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

/*
 * Test if the specified file is new enough to include in the archive.
 */
static 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)
                lafe_errc(1, ENOMEM, "Can't read archive directory");

        p->name = strdup(path);
        if (p->name == NULL)
                lafe_errc(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;
        }
}

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

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

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

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

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

/* Is this an appropriate check here on Windows? */
/*
        if (GetFileType(handle) != FILE_TYPE_DISK)
                lafe_errc(1, 0, "Cannot append");
*/

}