/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * tar2sqfs.c
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#include "tar2sqfs.h"

static int tar_probe(const sqfs_u8 *data, size_t size)
{
	size_t i, offset;

	if (size >= TAR_RECORD_SIZE) {
		for (i = 0; i < TAR_RECORD_SIZE; ++i) {
			if (data[i] != 0x00)
				break;
		}

		if (i == TAR_RECORD_SIZE) {
			data += TAR_RECORD_SIZE;
			size -= TAR_RECORD_SIZE;
		}
	}

	offset = offsetof(tar_header_t, magic);

	if (offset + 5 <= size) {
		if (memcmp(data + offset, "ustar", 5) == 0)
			return 1;
	}

	return 0;
}

static istream_t *magic_autowrap(istream_t *strm)
{
	xfrm_stream_t *xfrm = NULL;
	istream_t *wrapper = NULL;
	const sqfs_u8 *data;
	size_t avail;
	int ret;

	ret = istream_precache(strm);
	if (ret != 0)
		goto out;

	data = strm->buffer + strm->buffer_offset;
	avail = strm->buffer_used - strm->buffer_offset;

	ret = tar_probe(data, avail);
	if (ret > 0)
		return strm;

	ret = xfrm_compressor_id_from_magic(data, avail);
	if (ret <= 0)
		return strm;

	xfrm = decompressor_stream_create(ret);
	if (xfrm == NULL)
		goto out;

	wrapper = istream_xfrm_create(strm, xfrm);
out:
	sqfs_drop(strm);
	sqfs_drop(xfrm);
	return wrapper;
}

int main(int argc, char **argv)
{
	int status = EXIT_FAILURE;
	istream_t *input_file = NULL;
	sqfs_writer_t sqfs;

	process_args(argc, argv);

	input_file = istream_open_stdin();
	if (input_file == NULL)
		return EXIT_FAILURE;

	input_file = magic_autowrap(input_file);
	if (input_file == NULL)
		return EXIT_FAILURE;

	memset(&sqfs, 0, sizeof(sqfs));
	if (sqfs_writer_init(&sqfs, &cfg))
		goto out_if;

	if (process_tarball(input_file, &sqfs))
		goto out;

	if (fstree_post_process(&sqfs.fs))
		goto out;

	if (sqfs_writer_finish(&sqfs, &cfg))
		goto out;

	status = EXIT_SUCCESS;
out:
	sqfs_writer_cleanup(&sqfs, status);
out_if:
	sqfs_drop(input_file);
	return status;
}