source: mainline/uspace/app/untar/main.c@ ae7bbfd0

/*
 * 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 untar
 * @{
 */
/** @file
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <errno.h>
#include <str_error.h>
#include "tar.h"

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

static int skip_blocks(FILE *tarfile, 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 = fread(block, TAR_BLOCK_SIZE, 1, tarfile);
                if (actually_read != 1) {
                        return errno;
                }
                blocks_to_read--;
        }
        return EOK;
}

static int handle_normal_file(const tar_header_t *header, FILE *tarfile)
{
        // FIXME: create the directory first

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

        int 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 = fread(block, 1, TAR_BLOCK_SIZE, tarfile);
                if (actually_read != TAR_BLOCK_SIZE) {
                        rc = errno;
                        fprintf(stderr, "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;
                        fprintf(stderr, "Failed to write to %s: %s.\n",
                            header->filename, str_error(rc));
                        break;
                }
                blocks--;
                bytes_remaining -= TAR_BLOCK_SIZE;
        }

        fclose(file);

        return rc;
}

static int handle_directory(const tar_header_t *header, FILE *tarfile)
{
        if (mkdir(header->filename, 0755) != 0) {
                if (errno != EEXIST) {
                        fprintf(stderr, "Failed to create directory %s: %s.\n",
                            header->filename, str_error(errno));
                        return errno;
                }
        }

        return skip_blocks(tarfile, header->size);
}

int main(int argc, char *argv[])
{
        if (argc != 2) {
                fprintf(stderr, "Usage: %s tar-file\n", argv[0]);
                return 1;
        }

        const char *filename = argv[1];

        FILE *tarfile = fopen(filename, "rb");
        if (tarfile == NULL) {
                fprintf(stderr, "Failed to open `%s': %s.\n", filename, str_error(errno));
                return 2;
        }

        while (true) {
                size_t header_ok;
                tar_header_raw_t header_raw;
                tar_header_t header;
                header_ok = fread(&header_raw, sizeof(header_raw), 1, tarfile);
                if (header_ok != 1) {
                        break;
                }
                int rc = tar_header_parse(&header, &header_raw);
                if (rc == EEMPTY) {
                        continue;
                }
                if (rc != EOK) {
                        fprintf(stderr, "Failed parsing TAR header: %s.\n", str_error(rc));
                        break;
                }

                //printf(" ==> %s (%zuB, type %s)\n", header.filename,
                //    header.size, tar_type_str(header.type));

                switch (header.type) {
                case TAR_TYPE_DIRECTORY:
                        rc = handle_directory(&header, tarfile);
                        break;
                case TAR_TYPE_NORMAL:
                        rc = handle_normal_file(&header, tarfile);
                        break;
                default:
                        rc = skip_blocks(tarfile, header.size);
                        break;
                }
                if (rc != EOK) {
                        break;
                }

        }

        fclose(tarfile);

        return 0;
}

/** @}
 */