/*-
* Copyright (c) 2011 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: unxz.c,v 1.9 2024/05/04 13:17:03 christos Exp $");
for (;;) {
check_siginfo();
if (strm.avail_in == 0) {
strm.next_in = ibuf;
strm.avail_in = read(i, ibuf, sizeof(ibuf));
switch (strm.avail_in) {
case (size_t)-1:
maybe_err("read failed");
/*NOTREACHED*/
case 0:
action = LZMA_FINISH;
break;
default:
infile_newdata(strm.avail_in);
*bytes_in += strm.avail_in;
break;
}
}
ret = lzma_code(&strm, action);
// Write and check write error before checking decoder error.
// This way as much data as possible gets written to output
// even if decoder detected an error.
if (strm.avail_out == 0 || ret != LZMA_OK) {
const size_t write_size = sizeof(obuf) - strm.avail_out;
if (!tflag &&
write(o, obuf, write_size) != (ssize_t)write_size)
maybe_err("write failed");
/*
* Copied various bits and pieces from xz support code or brute force
* replacements.
*/
#define my_min(A,B) ((A)<(B)?(A):(B))
// Some systems have suboptimal BUFSIZ. Use a bit bigger value on them.
// We also need that IO_BUFFER_SIZE is a multiple of 8 (sizeof(uint64_t))
#if BUFSIZ <= 1024
# define IO_BUFFER_SIZE 8192
#else
# define IO_BUFFER_SIZE (BUFSIZ & ~7U)
#endif
/// is_sparse() accesses the buffer as uint64_t for maximum speed.
/// Use an union to make sure that the buffer is properly aligned.
typedef union {
uint8_t u8[IO_BUFFER_SIZE];
uint32_t u32[IO_BUFFER_SIZE / sizeof(uint32_t)];
uint64_t u64[IO_BUFFER_SIZE / sizeof(uint64_t)];
} io_buf;
static bool
io_pread(int fd, io_buf *buf, size_t size, off_t pos)
{
// Using lseek() and read() is more portable than pread() and
// for us it is as good as real pread().
if (lseek(fd, pos, SEEK_SET) != pos) {
return true;
}
/*
* Most of the following is copied (mostly verbatim) from the xz
* distribution, from file src/xz/list.c
*/
///////////////////////////////////////////////////////////////////////////////
//
/// \file list.c
/// \brief Listing information about .xz files
//
// Author: Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
/// Information about a .xz file
typedef struct {
/// Combined Index of all Streams in the file
lzma_index *idx;
/// Total amount of Stream Padding
uint64_t stream_padding;
/// Highest memory usage so far
uint64_t memusage_max;
/// True if all Blocks so far have Compressed Size and
/// Uncompressed Size fields
bool all_have_sizes;
/// Oldest XZ Utils version that will decompress the file
uint32_t min_version;
/// \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;
}
// 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;
}
// 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;
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;
}
/***************** end of copy form list.c *************************/
/*
* Small wrapper to extract total length of a file
*/
off_t
unxz_len(int fd)
{
xz_file_info xfi = XZ_FILE_INFO_INIT;
if (!parse_indexes(&xfi, fd)) {
off_t res = lzma_index_uncompressed_size(xfi.idx);
lzma_index_end(xfi.idx, NULL);
return res;
}
return 0;
}
