extern void
coder_set_compression_settings(void)
{
// The default check type is CRC64, but fallback to CRC32
// if CRC64 isn't supported by the copy of liblzma we are
// using. CRC32 is always supported.
if (check_default) {
check = LZMA_CHECK_CRC64;
if (!lzma_check_is_supported(check))
check = LZMA_CHECK_CRC32;
}
// Options for LZMA1 or LZMA2 in case we are using a preset.
static lzma_options_lzma opt_lzma;
if (filters_count == 0) {
// We are using a preset. This is not a good idea in raw mode
// except when playing around with things. Different versions
// of this software may use different options in presets, and
// thus make uncompressing the raw data difficult.
if (opt_format == FORMAT_RAW) {
// The message is shown only if warnings are allowed
// but the exit status isn't changed.
message(V_WARNING, _("Using a preset in raw mode "
"is discouraged."));
message(V_WARNING, _("The exact options of the "
"presets may vary between software "
"versions."));
}
// Get the preset for LZMA1 or LZMA2.
if (lzma_lzma_preset(&opt_lzma, preset_number))
message_bug();
// Use LZMA2 except with --format=lzma we use LZMA1.
filters[0].id = opt_format == FORMAT_LZMA
? LZMA_FILTER_LZMA1 : LZMA_FILTER_LZMA2;
filters[0].options = &opt_lzma;
filters_count = 1;
}
// Terminate the filter options array.
filters[filters_count].id = LZMA_VLI_UNKNOWN;
// If we are using the .lzma format, allow exactly one filter
// which has to be LZMA1.
if (opt_format == FORMAT_LZMA && (filters_count != 1
|| filters[0].id != LZMA_FILTER_LZMA1))
message_fatal(_("The .lzma format supports only "
"the LZMA1 filter"));
// If we are using the .xz format, make sure that there is no LZMA1
// filter to prevent LZMA_PROG_ERROR.
if (opt_format == FORMAT_XZ)
for (size_t i = 0; i < filters_count; ++i)
if (filters[i].id == LZMA_FILTER_LZMA1)
message_fatal(_("LZMA1 cannot be used "
"with the .xz format"));
// Print the selected filter chain.
message_filters_show(V_DEBUG, filters);
// Get the memory usage. Note that if --format=raw was used,
// we can be decompressing.
const uint64_t memory_limit = hardware_memlimit_get(opt_mode);
uint64_t memory_usage;
if (opt_mode == MODE_COMPRESS) {
#ifdef MYTHREAD_ENABLED
if (opt_format == FORMAT_XZ && hardware_threads_get() > 1) {
mt_options.threads = hardware_threads_get();
mt_options.block_size = opt_block_size;
mt_options.check = check;
memory_usage = lzma_stream_encoder_mt_memusage(
&mt_options);
if (memory_usage != UINT64_MAX)
message(V_DEBUG, _("Using up to %" PRIu32
" threads."),
mt_options.threads);
} else
#endif
{
memory_usage = lzma_raw_encoder_memusage(filters);
}
} else {
memory_usage = lzma_raw_decoder_memusage(filters);
}
if (memory_usage == UINT64_MAX)
message_fatal(_("Unsupported filter chain or filter options"));
// Print memory usage info before possible dictionary
// size auto-adjusting.
message_mem_needed(V_DEBUG, memory_usage);
if (opt_mode == MODE_COMPRESS) {
const uint64_t decmem = lzma_raw_decoder_memusage(filters);
if (decmem != UINT64_MAX)
message(V_DEBUG, _("Decompression will need "
"%s MiB of memory."), uint64_to_str(
round_up_to_mib(decmem), 0));
}
if (memory_usage <= memory_limit)
return;
// If --no-auto-adjust was used or we didn't find LZMA1 or
// LZMA2 as the last filter, give an error immediately.
// --format=raw implies --no-auto-adjust.
if (!opt_auto_adjust || opt_format == FORMAT_RAW)
memlimit_too_small(memory_usage);
assert(opt_mode == MODE_COMPRESS);
#ifdef MYTHREAD_ENABLED
if (opt_format == FORMAT_XZ && mt_options.threads > 1) {
// Try to reduce the number of threads before
// adjusting the compression settings down.
do {
// FIXME? The real single-threaded mode has
// lower memory usage, but it's not comparable
// because it doesn't write the size info
// into Block Headers.
if (--mt_options.threads == 0)
memlimit_too_small(memory_usage);
memory_usage = lzma_stream_encoder_mt_memusage(
&mt_options);
if (memory_usage == UINT64_MAX)
message_bug();
} while (memory_usage > memory_limit);
message(V_WARNING, _("Adjusted the number of threads "
"from %s to %s to not exceed "
"the memory usage limit of %s MiB"),
uint64_to_str(hardware_threads_get(), 0),
uint64_to_str(mt_options.threads, 1),
uint64_to_str(round_up_to_mib(
memory_limit), 2));
}
#endif
if (memory_usage <= memory_limit) {
return;
}
// Look for the last filter if it is LZMA2 or LZMA1, so we can make
// it use less RAM. With other filters we don't know what to do.
size_t i = 0;
while (filters[i].id != LZMA_FILTER_LZMA2
&& filters[i].id != LZMA_FILTER_LZMA1) {
if (filters[i].id == LZMA_VLI_UNKNOWN)
memlimit_too_small(memory_usage);
++i;
}
// Decrease the dictionary size until we meet the memory
// usage limit. First round down to full mebibytes.
lzma_options_lzma *opt = filters[i].options;
const uint32_t orig_dict_size = opt->dict_size;
opt->dict_size &= ~((UINT32_C(1) << 20) - 1);
while (true) {
// If it is below 1 MiB, auto-adjusting failed. We could be
// more sophisticated and scale it down even more, but let's
// see if many complain about this version.
//
// FIXME: Displays the scaled memory usage instead
// of the original.
if (opt->dict_size < (UINT32_C(1) << 20))
memlimit_too_small(memory_usage);
memory_usage = lzma_raw_encoder_memusage(filters);
if (memory_usage == UINT64_MAX)
message_bug();
// Accept it if it is low enough.
if (memory_usage <= memory_limit)
break;
// Otherwise 1 MiB down and try again. I hope this
// isn't too slow method for cases where the original
// dict_size is very big.
opt->dict_size -= UINT32_C(1) << 20;
}
// Tell the user that we decreased the dictionary size.
message(V_WARNING, _("Adjusted LZMA%c dictionary size "
"from %s MiB to %s MiB to not exceed "
"the memory usage limit of %s MiB"),
filters[i].id == LZMA_FILTER_LZMA2
? '2' : '1',
uint64_to_str(orig_dict_size >> 20, 0),
uint64_to_str(opt->dict_size >> 20, 1),
uint64_to_str(round_up_to_mib(memory_limit), 2));
return;
}
/// \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 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) {
message_error("%s: %s", pair->src_name,
message_strm(LZMA_OPTIONS_ERROR));
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;
}
