HelenOS sources

root/uspace/lib/untar/untar.c

DEFINITIONS

1. get_block_count
2. tar_open
3. tar_close
4. tar_read
5. tar_report
6. tar_skip_blocks
7. tar_handle_normal_file
8. tar_handle_directory
9. untar

/*
 * Copyright (c) 2013 Vojtech Horky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

/** @addtogroup libuntar
 * @{
 */
/** @file
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <str_error.h>
#include <vfs/vfs.h>
#include "private/tar.h"
#include "untar.h"

static size_t get_block_count(size_t bytes)
{
        return (bytes + TAR_BLOCK_SIZE - 1) / TAR_BLOCK_SIZE;
}

static int tar_open(tar_file_t *tar)
{
        return tar->open(tar);
}

static void tar_close(tar_file_t *tar)
{
        tar->close(tar);
}

static size_t tar_read(tar_file_t *tar, void *data, size_t size)
{
        return tar->read(tar, data, size);
}

static void tar_report(tar_file_t *tar, const char *fmt, ...)
{
        va_list args;
        va_start(args, fmt);

        tar->vreport(tar, fmt, args);

        va_end(args);
}

static errno_t tar_skip_blocks(tar_file_t *tar, size_t valid_data_size)
{
        size_t blocks_to_read = get_block_count(valid_data_size);

        while (blocks_to_read > 0) {
                uint8_t block[TAR_BLOCK_SIZE];
                size_t actually_read = tar_read(tar, block, TAR_BLOCK_SIZE);
                if (actually_read != TAR_BLOCK_SIZE)
                        return errno;

                blocks_to_read--;
        }

        return EOK;
}

static errno_t tar_handle_normal_file(tar_file_t *tar,
    const tar_header_t *header)
{
        // FIXME: create the directory first

        FILE *file = fopen(header->filename, "wb");
        if (file == NULL) {
                tar_report(tar, "Failed to create %s: %s.\n", header->filename,
                    str_error(errno));
                return errno;
        }

        errno_t rc = EOK;
        size_t bytes_remaining = header->size;
        size_t blocks = get_block_count(bytes_remaining);

        while (blocks > 0) {
                uint8_t block[TAR_BLOCK_SIZE];
                size_t actually_read = tar_read(tar, block, TAR_BLOCK_SIZE);
                if (actually_read != TAR_BLOCK_SIZE) {
                        rc = errno;
                        tar_report(tar, "Failed to read block for %s: %s.\n",
                            header->filename, str_error(rc));
                        break;
                }

                size_t to_write = TAR_BLOCK_SIZE;
                if (bytes_remaining < TAR_BLOCK_SIZE)
                        to_write = bytes_remaining;

                size_t actually_written = fwrite(block, 1, to_write, file);
                if (actually_written != to_write) {
                        rc = errno;
                        tar_report(tar, "Failed to write to %s: %s.\n",
                            header->filename, str_error(rc));
                        break;
                }

                blocks--;
                bytes_remaining -= TAR_BLOCK_SIZE;
        }

        fclose(file);
        return rc;
}

static errno_t tar_handle_directory(tar_file_t *tar, const tar_header_t *header)
{
        errno_t rc = vfs_link_path(header->filename, KIND_DIRECTORY, NULL);
        if (rc != EOK) {
                if (rc != EEXIST) {
                        tar_report(tar, "Failed to create directory %s: %s.\n",
                            header->filename, str_error(rc));
                        return rc;
                }
        }

        return tar_skip_blocks(tar, header->size);
}

int untar(tar_file_t *tar)
{
        int rc = tar_open(tar);
        if (rc != EOK) {
                tar_report(tar, "Failed to open: %s.\n", str_error(rc));
                return rc;
        }

        while (true) {
                tar_header_raw_t header_raw;
                size_t header_ok = tar_read(tar, &header_raw, sizeof(header_raw));
                if (header_ok != sizeof(header_raw))
                        break;

                tar_header_t header;
                errno_t rc = tar_header_parse(&header, &header_raw);
                if (rc == EEMPTY)
                        continue;

                if (rc != EOK) {
                        tar_report(tar, "Failed parsing TAR header: %s.\n", str_error(rc));
                        break;
                }

                switch (header.type) {
                case TAR_TYPE_DIRECTORY:
                        rc = tar_handle_directory(tar, &header);
                        break;
                case TAR_TYPE_NORMAL:
                        rc = tar_handle_normal_file(tar, &header);
                        break;
                default:
                        rc = tar_skip_blocks(tar, header.size);
                        break;
                }

                if (rc != EOK)
                        break;
        }

        tar_close(tar);
        return EOK;
}

/** @}
 */