コード例 #1
0
ファイル: xz-file.cpp プロジェクト: stbuehler/xz-jni
/* adapted from official xz source: xz/src/xz/list.c */
static lzma_index* read_index(File file, uint64_t memlimit, std::string &error) {
	union {
		unsigned char buf[4096];
		unsigned char u8[LZMA_STREAM_HEADER_SIZE];
		uint32_t u32[LZMA_STREAM_HEADER_SIZE/4];
	} buf;

	lzma_stream strm =  LZMA_STREAM_INIT;
	lzma_index *cur_index = nullptr;
	lzma_index *col_index = nullptr;
	FileReaderState *filestate = nullptr;

	lzma_stream_flags header_flags;
	lzma_stream_flags footer_flags;
	lzma_ret ret;

	// Current position in the file. We parse the file backwards so
	// initialize it to point to the end of the file.
	int64_t pos = file->filesize();;

	// Each loop iteration decodes one Index.
	do {
		lzma_vli stream_padding, index_size;
		uint64_t memused;

		// Check that there is enough data left to contain at least
		// the Stream Header and Stream Footer. This check cannot
		// fail in the first pass of this loop.
		if (pos < 2 * LZMA_STREAM_HEADER_SIZE) {
			error.assign("file too small for xz archive");
			goto failed;
		}

		pos -= LZMA_STREAM_HEADER_SIZE;
		stream_padding = 0;

		// Locate the Stream Footer. There may be Stream Padding which
		// we must skip when reading backwards.
		for (;;) {
			if (pos < LZMA_STREAM_HEADER_SIZE) {
				error.assign("file too small for xz archive");
				goto failed;
			}

			if (!file->readInto(filestate, pos, LZMA_STREAM_HEADER_SIZE, buf.buf, error)) goto failed;

			/* padding must be a multiple of 4 */
			if (buf.u32[2] != 0) break;
			pos -= 4; stream_padding += 4;
			if (buf.u32[1] != 0) break;
			pos -= 4; stream_padding += 4;
			if (buf.u32[0] != 0) break;
			pos -= 4; stream_padding += 4;
		}

		// Decode the Stream Footer.
		ret = lzma_stream_footer_decode(&footer_flags, buf.u8);
		if (LZMA_OK != ret) {
			errnoLzmaToStr("invalid footer", ret, error);
			goto failed;
		}

		// Check that the size of the Index field looks sane.
		index_size = footer_flags.backward_size;
		if ((lzma_vli)(pos) < index_size + LZMA_STREAM_HEADER_SIZE) {
			error.assign("invalid index size");
			goto failed;
		}

		// Set pos to the beginning of the Index.
		pos -= index_size;

		// See how much memory we can use for decoding this Index.
		memused = nullptr != col_index ? lzma_index_memused(col_index) : 0;
		if (memused > memlimit) {
			error.assign("mem limit hit");
			goto failed;
		}

		// Decode the Index.
		ret = lzma_index_decoder(&strm, &cur_index, memlimit - memused);
		if (ret != LZMA_OK) {
			errnoLzmaToStr("couldn't allocate new index", ret, error);
			goto failed;
		}

		do {
			ssize_t want = (index_size < sizeof(buf.buf) ? index_size : sizeof(buf.buf));
			if (want < 0) { ret = LZMA_DATA_ERROR; break; }

			if (!file->readInto(filestate, pos, want, buf.buf, error)) goto failed;

			strm.avail_in = want;
			strm.next_in = buf.buf;
			pos += want;
			index_size -= want;

			ret = lzma_code(&strm, LZMA_RUN);
		} while (ret == LZMA_OK);

		// If the decoding seems to be successful, check also that
		// the Index decoder consumed as much input as indicated
		// by the Backward Size field.
		if (ret == LZMA_STREAM_END)
			if (index_size != 0 || strm.avail_in != 0)
				ret = LZMA_DATA_ERROR;

		if (ret != LZMA_STREAM_END) {
			// LZMA_BUFFER_ERROR means that the Index decoder
			// would have liked more input than what the Index
			// size should be according to Stream Footer.
			// The message for LZMA_DATA_ERROR makes more
			// sense in that case.
			if (ret == LZMA_BUF_ERROR)
				ret = LZMA_DATA_ERROR;

			errnoLzmaToStr("decoding index failed", ret, error);
			goto failed;
		}

		// Decode the Stream Header and check that its Stream Flags
		// match the Stream Footer.
		pos -= footer_flags.backward_size + LZMA_STREAM_HEADER_SIZE;
		if ((lzma_vli)(pos) < lzma_index_total_size(cur_index)) {
			error.assign("invalid archive - index large than available data");
			goto failed;
		}

		pos -= lzma_index_total_size(cur_index);
		if (!file->readInto(filestate, pos, LZMA_STREAM_HEADER_SIZE, buf.buf, error)) goto failed;

		ret = lzma_stream_header_decode(&header_flags, buf.u8);
		if (ret != LZMA_OK) {
			errnoLzmaToStr("invalid header", ret, error);
			goto failed;
		}

		ret = lzma_stream_flags_compare(&header_flags, &footer_flags);
		if (ret != LZMA_OK) {
			errnoLzmaToStr("invalid stream: footer doesn't match header", ret, error);
			goto failed;
		}

		// Store the decoded Stream Flags into this_index. This is
		// needed so that we can print which Check is used in each
		// Stream.
		ret = lzma_index_stream_flags(cur_index, &footer_flags);
		if (ret != LZMA_OK) {
			errnoLzmaToStr("decoding stream flags failed", ret, error);
			goto failed;
		}

		// Store also the size of the Stream Padding field. It is
		// needed to show the offsets of the Streams correctly.
		ret = lzma_index_stream_padding(cur_index, stream_padding);
		if (ret != LZMA_OK) {
			errnoLzmaToStr("storing stream padding failed", ret, error);
			goto failed;
		}

		if (nullptr != col_index) {
			// Append the earlier decoded Indexes
			// after this_index.
			ret = lzma_index_cat(cur_index, col_index, NULL);
			col_index = nullptr;
			if (ret != LZMA_OK) {
				errnoLzmaToStr("failed to concatenate indexes", ret, error);
				goto failed;
			}
		}
		col_index = cur_index;
		cur_index = nullptr;
	} while (pos > 0);

	lzma_end(&strm);
	file->finish(filestate);

	return col_index;

failed:
	lzma_end(&strm);
	if (nullptr != cur_index) lzma_index_end(cur_index, NULL);
	if (nullptr != col_index) lzma_index_end(col_index, NULL);
	file->finish(filestate);

	return nullptr;
}
コード例 #2
0
ファイル: unxz.c プロジェクト: FreeBSDFoundation/freebsd
/// \brief      Parse the Index(es) from the given .xz file
///
/// \param      xfi     Pointer to structure where the decoded information
///                     is stored.
/// \param      pair    Input file
///
/// \return     On success, false is returned. On error, true is returned.
///
// TODO: This function is pretty big. liblzma should have a function that
// takes a callback function to parse the Index(es) from a .xz file to make
// it easy for applications.
static bool
parse_indexes(xz_file_info *xfi, int src_fd)
{
	struct stat st;

	fstat(src_fd, &st);
	if (st.st_size <= 0) {
		return true;
	}

	if (st.st_size < 2 * LZMA_STREAM_HEADER_SIZE) {
		return true;
	}

	io_buf buf;
	lzma_stream_flags header_flags;
	lzma_stream_flags footer_flags;
	lzma_ret ret;

	// lzma_stream for the Index decoder
	lzma_stream strm = LZMA_STREAM_INIT;

	// All Indexes decoded so far
	lzma_index *combined_index = NULL;

	// The Index currently being decoded
	lzma_index *this_index = NULL;

	// Current position in the file. We parse the file backwards so
	// initialize it to point to the end of the file.
	off_t pos = st.st_size;

	// Each loop iteration decodes one Index.
	do {
		// Check that there is enough data left to contain at least
		// the Stream Header and Stream Footer. This check cannot
		// fail in the first pass of this loop.
		if (pos < 2 * LZMA_STREAM_HEADER_SIZE) {
			goto error;
		}

		pos -= LZMA_STREAM_HEADER_SIZE;
		lzma_vli stream_padding = 0;

		// Locate the Stream Footer. There may be Stream Padding which
		// we must skip when reading backwards.
		while (true) {
			if (pos < LZMA_STREAM_HEADER_SIZE) {
				goto error;
			}

			if (io_pread(src_fd, &buf,
					LZMA_STREAM_HEADER_SIZE, pos))
				goto error;

			// Stream Padding is always a multiple of four bytes.
			int i = 2;
			if (buf.u32[i] != 0)
				break;

			// To avoid calling io_pread() for every four bytes
			// of Stream Padding, take advantage that we read
			// 12 bytes (LZMA_STREAM_HEADER_SIZE) already and
			// check them too before calling io_pread() again.
			do {
				stream_padding += 4;
				pos -= 4;
				--i;
			} while (i >= 0 && buf.u32[i] == 0);
		}

		// Decode the Stream Footer.
		ret = lzma_stream_footer_decode(&footer_flags, buf.u8);
		if (ret != LZMA_OK) {
			goto error;
		}

		// Check that the Stream Footer doesn't specify something
		// that we don't support. This can only happen if the xz
		// version is older than liblzma and liblzma supports
		// something new.
		//
		// It is enough to check Stream Footer. Stream Header must
		// match when it is compared against Stream Footer with
		// lzma_stream_flags_compare().
		if (footer_flags.version != 0) {
			goto error;
		}

		// Check that the size of the Index field looks sane.
		lzma_vli index_size = footer_flags.backward_size;
		if ((lzma_vli)(pos) < index_size + LZMA_STREAM_HEADER_SIZE) {
			goto error;
		}

		// Set pos to the beginning of the Index.
		pos -= index_size;

		// Decode the Index.
		ret = lzma_index_decoder(&strm, &this_index, UINT64_MAX);
		if (ret != LZMA_OK) {
			goto error;
		}

		do {
			// Don't give the decoder more input than the
			// Index size.
			strm.avail_in = my_min(IO_BUFFER_SIZE, index_size);
			if (io_pread(src_fd, &buf, strm.avail_in, pos))
				goto error;

			pos += strm.avail_in;
			index_size -= strm.avail_in;

			strm.next_in = buf.u8;
			ret = lzma_code(&strm, LZMA_RUN);

		} while (ret == LZMA_OK);

		// If the decoding seems to be successful, check also that
		// the Index decoder consumed as much input as indicated
		// by the Backward Size field.
		if (ret == LZMA_STREAM_END)
			if (index_size != 0 || strm.avail_in != 0)
				ret = LZMA_DATA_ERROR;

		if (ret != LZMA_STREAM_END) {
			// LZMA_BUFFER_ERROR means that the Index decoder
			// would have liked more input than what the Index
			// size should be according to Stream Footer.
			// The message for LZMA_DATA_ERROR makes more
			// sense in that case.
			if (ret == LZMA_BUF_ERROR)
				ret = LZMA_DATA_ERROR;

			goto error;
		}

		// Decode the Stream Header and check that its Stream Flags
		// match the Stream Footer.
		pos -= footer_flags.backward_size + LZMA_STREAM_HEADER_SIZE;
		if ((lzma_vli)(pos) < lzma_index_total_size(this_index)) {
			goto error;
		}

		pos -= lzma_index_total_size(this_index);
		if (io_pread(src_fd, &buf, LZMA_STREAM_HEADER_SIZE, pos))
			goto error;

		ret = lzma_stream_header_decode(&header_flags, buf.u8);
		if (ret != LZMA_OK) {
			goto error;
		}

		ret = lzma_stream_flags_compare(&header_flags, &footer_flags);
		if (ret != LZMA_OK) {
			goto error;
		}

		// Store the decoded Stream Flags into this_index. This is
		// needed so that we can print which Check is used in each
		// Stream.
		ret = lzma_index_stream_flags(this_index, &footer_flags);
		if (ret != LZMA_OK)
			goto error;

		// Store also the size of the Stream Padding field. It is
		// needed to show the offsets of the Streams correctly.
		ret = lzma_index_stream_padding(this_index, stream_padding);
		if (ret != LZMA_OK)
			goto error;

		if (combined_index != NULL) {
			// Append the earlier decoded Indexes
			// after this_index.
			ret = lzma_index_cat(
					this_index, combined_index, NULL);
			if (ret != LZMA_OK) {
				goto error;
			}
		}

		combined_index = this_index;
		this_index = NULL;

		xfi->stream_padding += stream_padding;

	} while (pos > 0);

	lzma_end(&strm);

	// All OK. Make combined_index available to the caller.
	xfi->idx = combined_index;
	return false;

error:
	// Something went wrong, free the allocated memory.
	lzma_end(&strm);
	lzma_index_end(combined_index, NULL);
	lzma_index_end(this_index, NULL);
	return true;
}
コード例 #3
0
ファイル: list.c プロジェクト: AgamAgarwal/minix
/// \brief      Parse the Index(es) from the given .xz file
///
/// \param      xfi     Pointer to structure where the decoded information
///                     is stored.
/// \param      pair    Input file
///
/// \return     On success, false is returned. On error, true is returned.
///
// TODO: This function is pretty big. liblzma should have a function that
// takes a callback function to parse the Index(es) from a .xz file to make
// it easy for applications.
static bool
parse_indexes(xz_file_info *xfi, file_pair *pair)
{
	if (pair->src_st.st_size <= 0) {
		message_error(_("%s: File is empty"), pair->src_name);
		return true;
	}

	if (pair->src_st.st_size < 2 * LZMA_STREAM_HEADER_SIZE) {
		message_error(_("%s: Too small to be a valid .xz file"),
				pair->src_name);
		return true;
	}

	io_buf buf;
	lzma_stream_flags header_flags;
	lzma_stream_flags footer_flags;
	lzma_ret ret;

	// lzma_stream for the Index decoder
	lzma_stream strm = LZMA_STREAM_INIT;

	// All Indexes decoded so far
	lzma_index *combined_index = NULL;

	// The Index currently being decoded
	lzma_index *this_index = NULL;

	// Current position in the file. We parse the file backwards so
	// initialize it to point to the end of the file.
	off_t pos = pair->src_st.st_size;

	// Each loop iteration decodes one Index.
	do {
		// Check that there is enough data left to contain at least
		// the Stream Header and Stream Footer. This check cannot
		// fail in the first pass of this loop.
		if (pos < 2 * LZMA_STREAM_HEADER_SIZE) {
			message_error("%s: %s", pair->src_name,
					message_strm(LZMA_DATA_ERROR));
			goto error;
		}

		pos -= LZMA_STREAM_HEADER_SIZE;
		lzma_vli stream_padding = 0;

		// Locate the Stream Footer. There may be Stream Padding which
		// we must skip when reading backwards.
		while (true) {
			if (pos < LZMA_STREAM_HEADER_SIZE) {
				message_error("%s: %s", pair->src_name,
						message_strm(
							LZMA_DATA_ERROR));
				goto error;
			}

			if (io_pread(pair, &buf,
					LZMA_STREAM_HEADER_SIZE, pos))
				goto error;

			// Stream Padding is always a multiple of four bytes.
			int i = 2;
			if (buf.u32[i] != 0)
				break;

			// To avoid calling io_pread() for every four bytes
			// of Stream Padding, take advantage that we read
			// 12 bytes (LZMA_STREAM_HEADER_SIZE) already and
			// check them too before calling io_pread() again.
			do {
				stream_padding += 4;
				pos -= 4;
				--i;
			} while (i >= 0 && buf.u32[i] == 0);
		}

		// Decode the Stream Footer.
		ret = lzma_stream_footer_decode(&footer_flags, buf.u8);
		if (ret != LZMA_OK) {
			message_error("%s: %s", pair->src_name,
					message_strm(ret));
			goto error;
		}

		// Check that the size of the Index field looks sane.
		lzma_vli index_size = footer_flags.backward_size;
		if ((lzma_vli)(pos) < index_size + LZMA_STREAM_HEADER_SIZE) {
			message_error("%s: %s", pair->src_name,
					message_strm(LZMA_DATA_ERROR));
			goto error;
		}

		// Set pos to the beginning of the Index.
		pos -= index_size;

		// See how much memory we can use for decoding this Index.
		uint64_t memlimit = hardware_memlimit_get(MODE_LIST);
		uint64_t memused = 0;
		if (combined_index != NULL) {
			memused = lzma_index_memused(combined_index);
			if (memused > memlimit)
				message_bug();

			memlimit -= memused;
		}

		// Decode the Index.
		ret = lzma_index_decoder(&strm, &this_index, memlimit);
		if (ret != LZMA_OK) {
			message_error("%s: %s", pair->src_name,
					message_strm(ret));
			goto error;
		}

		do {
			// Don't give the decoder more input than the
			// Index size.
			strm.avail_in = my_min(IO_BUFFER_SIZE, index_size);
			if (io_pread(pair, &buf, strm.avail_in, pos))
				goto error;

			pos += strm.avail_in;
			index_size -= strm.avail_in;

			strm.next_in = buf.u8;
			ret = lzma_code(&strm, LZMA_RUN);

		} while (ret == LZMA_OK);

		// If the decoding seems to be successful, check also that
		// the Index decoder consumed as much input as indicated
		// by the Backward Size field.
		if (ret == LZMA_STREAM_END)
			if (index_size != 0 || strm.avail_in != 0)
				ret = LZMA_DATA_ERROR;

		if (ret != LZMA_STREAM_END) {
			// LZMA_BUFFER_ERROR means that the Index decoder
			// would have liked more input than what the Index
			// size should be according to Stream Footer.
			// The message for LZMA_DATA_ERROR makes more
			// sense in that case.
			if (ret == LZMA_BUF_ERROR)
				ret = LZMA_DATA_ERROR;

			message_error("%s: %s", pair->src_name,
					message_strm(ret));

			// If the error was too low memory usage limit,
			// show also how much memory would have been needed.
			if (ret == LZMA_MEMLIMIT_ERROR) {
				uint64_t needed = lzma_memusage(&strm);
				if (UINT64_MAX - needed < memused)
					needed = UINT64_MAX;
				else
					needed += memused;

				message_mem_needed(V_ERROR, needed);
			}

			goto error;
		}

		// Decode the Stream Header and check that its Stream Flags
		// match the Stream Footer.
		pos -= footer_flags.backward_size + LZMA_STREAM_HEADER_SIZE;
		if ((lzma_vli)(pos) < lzma_index_total_size(this_index)) {
			message_error("%s: %s", pair->src_name,
					message_strm(LZMA_DATA_ERROR));
			goto error;
		}

		pos -= lzma_index_total_size(this_index);
		if (io_pread(pair, &buf, LZMA_STREAM_HEADER_SIZE, pos))
			goto error;

		ret = lzma_stream_header_decode(&header_flags, buf.u8);
		if (ret != LZMA_OK) {
			message_error("%s: %s", pair->src_name,
					message_strm(ret));
			goto error;
		}

		ret = lzma_stream_flags_compare(&header_flags, &footer_flags);
		if (ret != LZMA_OK) {
			message_error("%s: %s", pair->src_name,
					message_strm(ret));
			goto error;
		}

		// Store the decoded Stream Flags into this_index. This is
		// needed so that we can print which Check is used in each
		// Stream.
		ret = lzma_index_stream_flags(this_index, &footer_flags);
		if (ret != LZMA_OK)
			message_bug();

		// Store also the size of the Stream Padding field. It is
		// needed to show the offsets of the Streams correctly.
		ret = lzma_index_stream_padding(this_index, stream_padding);
		if (ret != LZMA_OK)
			message_bug();

		if (combined_index != NULL) {
			// Append the earlier decoded Indexes
			// after this_index.
			ret = lzma_index_cat(
					this_index, combined_index, NULL);
			if (ret != LZMA_OK) {
				message_error("%s: %s", pair->src_name,
						message_strm(ret));
				goto error;
			}
		}

		combined_index = this_index;
		this_index = NULL;

		xfi->stream_padding += stream_padding;

	} while (pos > 0);

	lzma_end(&strm);

	// All OK. Make combined_index available to the caller.
	xfi->idx = combined_index;
	return false;

error:
	// Something went wrong, free the allocated memory.
	lzma_end(&strm);
	lzma_index_end(combined_index, NULL);
	lzma_index_end(this_index, NULL);
	return true;
}