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Apache Commons Compress software defines an API for working with
compression and archive formats. These include: bzip2, gzip, pack200,
lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4,
Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.commons.compress.archivers.tar;
import java.io.IOException;
import java.io.InputStream;
import java.io.UncheckedIOException;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.compress.archivers.zip.ZipEncoding;
import org.apache.commons.compress.archivers.zip.ZipEncodingHelper;
import org.apache.commons.compress.utils.IOUtils;
import org.apache.commons.compress.utils.ParsingUtils;
import org.apache.commons.io.output.ByteArrayOutputStream;
/**
* This class provides static utility methods to work with byte streams.
*
* @Immutable
*/
// CheckStyle:HideUtilityClassConstructorCheck OFF (bc)
public class TarUtils {
private static final int BYTE_MASK = 255;
static final ZipEncoding DEFAULT_ENCODING = ZipEncodingHelper.getZipEncoding(Charset.defaultCharset());
/**
* Encapsulates the algorithms used up to Commons Compress 1.3 as ZipEncoding.
*/
static final ZipEncoding FALLBACK_ENCODING = new ZipEncoding() {
@Override
public boolean canEncode(final String name) {
return true;
}
@Override
public String decode(final byte[] buffer) {
final int length = buffer.length;
final StringBuilder result = new StringBuilder(length);
for (final byte b : buffer) {
if (b == 0) { // Trailing null
break;
}
result.append((char) (b & 0xFF)); // Allow for sign-extension
}
return result.toString();
}
@Override
public ByteBuffer encode(final String name) {
final int length = name.length();
final byte[] buf = new byte[length];
// copy until end of input or output is reached.
for (int i = 0; i < length; ++i) {
buf[i] = (byte) name.charAt(i);
}
return ByteBuffer.wrap(buf);
}
};
/**
* Computes the checksum of a tar entry header.
*
* @param buf The tar entry's header buffer.
* @return The computed checksum.
*/
public static long computeCheckSum(final byte[] buf) {
long sum = 0;
for (final byte element : buf) {
sum += BYTE_MASK & element;
}
return sum;
}
// Helper method to generate the exception message
private static String exceptionMessage(final byte[] buffer, final int offset, final int length, final int current, final byte currentByte) {
// default charset is good enough for an exception message,
//
// the alternative was to modify parseOctal and
// parseOctalOrBinary to receive the ZipEncoding of the
// archive (deprecating the existing public methods, of
// course) and dealing with the fact that ZipEncoding#decode
// can throw an IOException which parseOctal* doesn't declare
String string = new String(buffer, offset, length, Charset.defaultCharset());
string = string.replace("\0", "{NUL}"); // Replace NULs to allow string to be printed
return "Invalid byte " + currentByte + " at offset " + (current - offset) + " in '" + string + "' len=" + length;
}
private static void formatBigIntegerBinary(final long value, final byte[] buf, final int offset, final int length, final boolean negative) {
final BigInteger val = BigInteger.valueOf(value);
final byte[] b = val.toByteArray();
final int len = b.length;
if (len > length - 1) {
throw new IllegalArgumentException("Value " + value + " is too large for " + length + " byte field.");
}
final int off = offset + length - len;
System.arraycopy(b, 0, buf, off, len);
final byte fill = (byte) (negative ? 0xff : 0);
for (int i = offset + 1; i < off; i++) {
buf[i] = fill;
}
}
/**
* Writes an octal value into a buffer.
*
* Uses {@link #formatUnsignedOctalString} to format the value as an octal string with leading zeros. The converted number is followed by NUL and then
* space.
*
* @param value The value to convert
* @param buf The destination buffer
* @param offset The starting offset into the buffer.
* @param length The size of the buffer.
* @return The updated value of offset, i.e. offset+length
* @throws IllegalArgumentException if the value (and trailer) will not fit in the buffer
*/
public static int formatCheckSumOctalBytes(final long value, final byte[] buf, final int offset, final int length) {
int idx = length - 2; // for NUL and space
formatUnsignedOctalString(value, buf, offset, idx);
buf[offset + idx++] = 0; // Trailing null
buf[offset + idx] = (byte) ' '; // Trailing space
return offset + length;
}
private static void formatLongBinary(final long value, final byte[] buf, final int offset, final int length, final boolean negative) {
final int bits = (length - 1) * 8;
final long max = 1L << bits;
long val = Math.abs(value); // Long.MIN_VALUE stays Long.MIN_VALUE
if (val < 0 || val >= max) {
throw new IllegalArgumentException("Value " + value + " is too large for " + length + " byte field.");
}
if (negative) {
val ^= max - 1;
val++;
val |= 0xffL << bits;
}
for (int i = offset + length - 1; i >= offset; i--) {
buf[i] = (byte) val;
val >>= 8;
}
}
/**
* Writes an octal long integer into a buffer.
*
* Uses {@link #formatUnsignedOctalString} to format the value as an octal string with leading zeros. The converted number is followed by a space.
*
* @param value The value to write as octal
* @param buf The destinationbuffer.
* @param offset The starting offset into the buffer.
* @param length The length of the buffer
* @return The updated offset
* @throws IllegalArgumentException if the value (and trailer) will not fit in the buffer
*/
public static int formatLongOctalBytes(final long value, final byte[] buf, final int offset, final int length) {
final int idx = length - 1; // For space
formatUnsignedOctalString(value, buf, offset, idx);
buf[offset + idx] = (byte) ' '; // Trailing space
return offset + length;
}
/**
* Writes a long integer into a buffer as an octal string if this will fit, or as a binary number otherwise.
*
* Uses {@link #formatUnsignedOctalString} to format the value as an octal string with leading zeros. The converted number is followed by a space.
*
* @param value The value to write into the buffer.
* @param buf The destination buffer.
* @param offset The starting offset into the buffer.
* @param length The length of the buffer.
* @return The updated offset.
* @throws IllegalArgumentException if the value (and trailer) will not fit in the buffer.
* @since 1.4
*/
public static int formatLongOctalOrBinaryBytes(final long value, final byte[] buf, final int offset, final int length) {
// Check whether we are dealing with UID/GID or SIZE field
final long maxAsOctalChar = length == TarConstants.UIDLEN ? TarConstants.MAXID : TarConstants.MAXSIZE;
final boolean negative = value < 0;
if (!negative && value <= maxAsOctalChar) { // OK to store as octal chars
return formatLongOctalBytes(value, buf, offset, length);
}
if (length < 9) {
formatLongBinary(value, buf, offset, length, negative);
} else {
formatBigIntegerBinary(value, buf, offset, length, negative);
}
buf[offset] = (byte) (negative ? 0xff : 0x80);
return offset + length;
}
/**
* Copies a name into a buffer. Copies characters from the name into the buffer starting at the specified offset. If the buffer is longer than the name, the
* buffer is filled with trailing NULs. If the name is longer than the buffer, the output is truncated.
*
* @param name The header name from which to copy the characters.
* @param buf The buffer where the name is to be stored.
* @param offset The starting offset into the buffer
* @param length The maximum number of header bytes to copy.
* @return The updated offset, i.e. offset + length
*/
public static int formatNameBytes(final String name, final byte[] buf, final int offset, final int length) {
try {
return formatNameBytes(name, buf, offset, length, DEFAULT_ENCODING);
} catch (final IOException ex) { // NOSONAR
try {
return formatNameBytes(name, buf, offset, length, FALLBACK_ENCODING);
} catch (final IOException ex2) {
// impossible
throw new UncheckedIOException(ex2); // NOSONAR
}
}
}
/**
* Copies a name into a buffer. Copies characters from the name into the buffer starting at the specified offset. If the buffer is longer than the name, the
* buffer is filled with trailing NULs. If the name is longer than the buffer, the output is truncated.
*
* @param name The header name from which to copy the characters.
* @param buf The buffer where the name is to be stored.
* @param offset The starting offset into the buffer
* @param length The maximum number of header bytes to copy.
* @param encoding name of the encoding to use for file names
* @since 1.4
* @return The updated offset, i.e. offset + length
* @throws IOException on error
*/
public static int formatNameBytes(final String name, final byte[] buf, final int offset, final int length, final ZipEncoding encoding) throws IOException {
int len = name.length();
ByteBuffer b = encoding.encode(name);
while (b.limit() > length && len > 0) {
b = encoding.encode(name.substring(0, --len));
}
final int limit = b.limit() - b.position();
System.arraycopy(b.array(), b.arrayOffset(), buf, offset, limit);
// Pad any remaining output bytes with NUL
for (int i = limit; i < length; ++i) {
buf[offset + i] = 0;
}
return offset + length;
}
/**
* Writes an octal integer into a buffer.
*
* Uses {@link #formatUnsignedOctalString} to format the value as an octal string with leading zeros. The converted number is followed by space and NUL
*
* @param value The value to write
* @param buf The buffer to receive the output
* @param offset The starting offset into the buffer
* @param length The size of the output buffer
* @return The updated offset, i.e. offset+length
* @throws IllegalArgumentException if the value (and trailer) will not fit in the buffer
*/
public static int formatOctalBytes(final long value, final byte[] buf, final int offset, final int length) {
int idx = length - 2; // For space and trailing null
formatUnsignedOctalString(value, buf, offset, idx);
buf[offset + idx++] = (byte) ' '; // Trailing space
buf[offset + idx] = 0; // Trailing null
return offset + length;
}
/**
* Fills a buffer with unsigned octal number, padded with leading zeroes.
*
* @param value number to convert to octal - treated as unsigned
* @param buffer destination buffer
* @param offset starting offset in buffer
* @param length length of buffer to fill
* @throws IllegalArgumentException if the value will not fit in the buffer
*/
public static void formatUnsignedOctalString(final long value, final byte[] buffer, final int offset, final int length) {
int remaining = length;
remaining--;
if (value == 0) {
buffer[offset + remaining--] = (byte) '0';
} else {
long val = value;
for (; remaining >= 0 && val != 0; --remaining) {
// CheckStyle:MagicNumber OFF
buffer[offset + remaining] = (byte) ((byte) '0' + (byte) (val & 7));
val = val >>> 3;
// CheckStyle:MagicNumber ON
}
if (val != 0) {
throw new IllegalArgumentException(value + "=" + Long.toOctalString(value) + " will not fit in octal number buffer of length " + length);
}
}
for (; remaining >= 0; --remaining) { // leading zeros
buffer[offset + remaining] = (byte) '0';
}
}
private static long parseBinaryBigInteger(final byte[] buffer, final int offset, final int length, final boolean negative) {
final byte[] remainder = new byte[length - 1];
System.arraycopy(buffer, offset + 1, remainder, 0, length - 1);
BigInteger val = new BigInteger(remainder);
if (negative) {
// 2's complement
val = val.add(BigInteger.valueOf(-1)).not();
}
if (val.bitLength() > 63) {
throw new IllegalArgumentException("At offset " + offset + ", " + length + " byte binary number exceeds maximum signed long value");
}
return negative ? -val.longValue() : val.longValue();
}
private static long parseBinaryLong(final byte[] buffer, final int offset, final int length, final boolean negative) {
if (length >= 9) {
throw new IllegalArgumentException("At offset " + offset + ", " + length + " byte binary number exceeds maximum signed long value");
}
long val = 0;
for (int i = 1; i < length; i++) {
val = (val << 8) + (buffer[offset + i] & 0xff);
}
if (negative) {
// 2's complement
val--;
val ^= (long) Math.pow(2.0, (length - 1) * 8.0) - 1;
}
return negative ? -val : val;
}
/**
* Parses a boolean byte from a buffer. Leading spaces and NUL are ignored. The buffer may contain trailing spaces or NULs.
*
* @param buffer The buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @return The boolean value of the bytes.
* @throws IllegalArgumentException if an invalid byte is detected.
*/
public static boolean parseBoolean(final byte[] buffer, final int offset) {
return buffer[offset] == 1;
}
/**
* For PAX Format 0.1, the sparse headers are stored in a single variable : GNU.sparse.map GNU.sparse.map Map of non-null data chunks. It is a string
* consisting of comma-separated values "offset,size[,offset-1,size-1...]"
*
* @param sparseMap the sparse map string consisting of comma-separated values "offset,size[,offset-1,size-1...]"
* @return unmodifiable list of sparse headers parsed from sparse map
* @throws IOException Corrupted TAR archive.
* @since 1.21
*/
protected static List parseFromPAX01SparseHeaders(final String sparseMap) throws IOException {
final List sparseHeaders = new ArrayList<>();
final String[] sparseHeaderStrings = sparseMap.split(",");
if (sparseHeaderStrings.length % 2 == 1) {
throw new IOException("Corrupted TAR archive. Bad format in GNU.sparse.map PAX Header");
}
for (int i = 0; i < sparseHeaderStrings.length; i += 2) {
final long sparseOffset = ParsingUtils.parseLongValue(sparseHeaderStrings[i]);
if (sparseOffset < 0) {
throw new IOException("Corrupted TAR archive. Sparse struct offset contains negative value");
}
final long sparseNumbytes = ParsingUtils.parseLongValue(sparseHeaderStrings[i + 1]);
if (sparseNumbytes < 0) {
throw new IOException("Corrupted TAR archive. Sparse struct numbytes contains negative value");
}
sparseHeaders.add(new TarArchiveStructSparse(sparseOffset, sparseNumbytes));
}
return Collections.unmodifiableList(sparseHeaders);
}
/**
* Parses an entry name from a buffer. Parsing stops when a NUL is found or the buffer length is reached.
*
* @param buffer The buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The maximum number of bytes to parse.
* @return The entry name.
*/
public static String parseName(final byte[] buffer, final int offset, final int length) {
try {
return parseName(buffer, offset, length, DEFAULT_ENCODING);
} catch (final IOException ex) { // NOSONAR
try {
return parseName(buffer, offset, length, FALLBACK_ENCODING);
} catch (final IOException ex2) {
// impossible
throw new UncheckedIOException(ex2); // NOSONAR
}
}
}
/**
* Parses an entry name from a buffer. Parsing stops when a NUL is found or the buffer length is reached.
*
* @param buffer The buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The maximum number of bytes to parse.
* @param encoding name of the encoding to use for file names
* @since 1.4
* @return The entry name.
* @throws IOException on error
*/
public static String parseName(final byte[] buffer, final int offset, final int length, final ZipEncoding encoding) throws IOException {
int len = 0;
for (int i = offset; len < length && buffer[i] != 0; i++) {
len++;
}
if (len > 0) {
final byte[] b = new byte[len];
System.arraycopy(buffer, offset, b, 0, len);
return encoding.decode(b);
}
return "";
}
/**
* Parses an octal string from a buffer.
*
*
* Leading spaces are ignored. The buffer must contain a trailing space or NUL, and may contain an additional trailing space or NUL.
*
*
*
* The input buffer is allowed to contain all NULs, in which case the method returns 0L (this allows for missing fields).
*
*
*
* To work-around some tar implementations that insert a leading NUL this method returns 0 if it detects a leading NUL since Commons Compress 1.4.
*
*
* @param buffer The buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The maximum number of bytes to parse - must be at least 2 bytes.
* @return The long value of the octal string.
* @throws IllegalArgumentException if the trailing space/NUL is missing or if an invalid byte is detected.
*/
public static long parseOctal(final byte[] buffer, final int offset, final int length) {
long result = 0;
int end = offset + length;
int start = offset;
if (length < 2) {
throw new IllegalArgumentException("Length " + length + " must be at least 2");
}
if (buffer[start] == 0) {
return 0L;
}
// Skip leading spaces
while (start < end) {
if (buffer[start] != ' ') {
break;
}
start++;
}
// Trim all trailing NULs and spaces.
// The ustar and POSIX tar specs require a trailing NUL or
// space but some implementations use the extra digit for big
// sizes/uids/gids ...
byte trailer = buffer[end - 1];
while (start < end && (trailer == 0 || trailer == ' ')) {
end--;
trailer = buffer[end - 1];
}
for (; start < end; start++) {
final byte currentByte = buffer[start];
// CheckStyle:MagicNumber OFF
if (currentByte < '0' || currentByte > '7') {
throw new IllegalArgumentException(exceptionMessage(buffer, offset, length, start, currentByte));
}
result = (result << 3) + (currentByte - '0'); // convert from ASCII
// CheckStyle:MagicNumber ON
}
return result;
}
/**
* Computes the value contained in a byte buffer. If the most significant bit of the first byte in the buffer is set, this bit is ignored and the rest of
* the buffer is interpreted as a binary number. Otherwise, the buffer is interpreted as an octal number as per the parseOctal function above.
*
* @param buffer The buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The maximum number of bytes to parse.
* @return The long value of the octal or binary string.
* @throws IllegalArgumentException if the trailing space/NUL is missing or an invalid byte is detected in an octal number, or if a binary number would
* exceed the size of a signed long 64-bit integer.
* @since 1.4
*/
public static long parseOctalOrBinary(final byte[] buffer, final int offset, final int length) {
if ((buffer[offset] & 0x80) == 0) {
return parseOctal(buffer, offset, length);
}
final boolean negative = buffer[offset] == (byte) 0xff;
if (length < 9) {
return parseBinaryLong(buffer, offset, length, negative);
}
return parseBinaryBigInteger(buffer, offset, length, negative);
}
/**
* For PAX Format 0.1, the sparse headers are stored in a single variable : GNU.sparse.map
*
*
* GNU.sparse.map: Map of non-null data chunks. It is a string consisting of comma-separated values "offset,size[,offset-1,size-1...]"
*
*
* Will internally invoke {@link #parseFromPAX01SparseHeaders} and map IOExceptions to a RzuntimeException, You should use
* {@link #parseFromPAX01SparseHeaders} directly instead.
*
*
* @param sparseMap the sparse map string consisting of comma-separated values "offset,size[,offset-1,size-1...]"
* @return sparse headers parsed from sparse map
* @deprecated use #parseFromPAX01SparseHeaders instead
*/
@Deprecated
protected static List parsePAX01SparseHeaders(final String sparseMap) {
try {
return parseFromPAX01SparseHeaders(sparseMap);
} catch (final IOException ex) {
throw new UncheckedIOException(ex.getMessage(), ex);
}
}
/**
* For PAX Format 1.X: The sparse map itself is stored in the file data block, preceding the actual file data. It consists of a series of decimal numbers
* delimited by newlines. The map is padded with nulls to the nearest block boundary. The first number gives the number of entries in the map. Following are
* map entries, each one consisting of two numbers giving the offset and size of the data block it describes.
*
* @param inputStream parsing source.
* @param recordSize The size the TAR header
* @return sparse headers
* @throws IOException if an I/O error occurs.
*/
protected static List parsePAX1XSparseHeaders(final InputStream inputStream, final int recordSize) throws IOException {
// for 1.X PAX Headers
final List sparseHeaders = new ArrayList<>();
long bytesRead = 0;
long[] readResult = readLineOfNumberForPax1X(inputStream);
long sparseHeadersCount = readResult[0];
if (sparseHeadersCount < 0) {
// overflow while reading number?
throw new IOException("Corrupted TAR archive. Negative value in sparse headers block");
}
bytesRead += readResult[1];
while (sparseHeadersCount-- > 0) {
readResult = readLineOfNumberForPax1X(inputStream);
final long sparseOffset = readResult[0];
if (sparseOffset < 0) {
throw new IOException("Corrupted TAR archive. Sparse header block offset contains negative value");
}
bytesRead += readResult[1];
readResult = readLineOfNumberForPax1X(inputStream);
final long sparseNumbytes = readResult[0];
if (sparseNumbytes < 0) {
throw new IOException("Corrupted TAR archive. Sparse header block numbytes contains negative value");
}
bytesRead += readResult[1];
sparseHeaders.add(new TarArchiveStructSparse(sparseOffset, sparseNumbytes));
}
// skip the rest of this record data
final long bytesToSkip = recordSize - bytesRead % recordSize;
org.apache.commons.io.IOUtils.skip(inputStream, bytesToSkip);
return sparseHeaders;
}
/**
* For PAX Format 0.0, the sparse headers(GNU.sparse.offset and GNU.sparse.numbytes) may appear multi times, and they look like:
*
*
* GNU.sparse.size=size
* GNU.sparse.numblocks=numblocks
* repeat numblocks times
* GNU.sparse.offset=offset
* GNU.sparse.numbytes=numbytes
* end repeat
*
*
* For PAX Format 0.1, the sparse headers are stored in a single variable: GNU.sparse.map
*
*
* GNU.sparse.map: Map of non-null data chunks. It is a string consisting of comma-separated values "offset,size[,offset-1,size-1...]"
*
*
* @param inputStream input stream to read keys and values
* @param sparseHeaders used in PAX Format 0.0 & 0.1, as it may appear multiple times, the sparse headers need to be stored in an array, not a map
* @param globalPaxHeaders global PAX headers of the tar archive
* @return map of PAX headers values found inside the current (local or global) PAX headers tar entry.
* @throws IOException if an I/O error occurs.
* @deprecated use the four-arg version instead
*/
@Deprecated
protected static Map parsePaxHeaders(final InputStream inputStream, final List sparseHeaders,
final Map globalPaxHeaders) throws IOException {
return parsePaxHeaders(inputStream, sparseHeaders, globalPaxHeaders, -1);
}
/**
* For PAX Format 0.0, the sparse headers(GNU.sparse.offset and GNU.sparse.numbytes) may appear multi times, and they look like:
*
*
* GNU.sparse.size=size
* GNU.sparse.numblocks=numblocks
* repeat numblocks times
* GNU.sparse.offset=offset
* GNU.sparse.numbytes=numbytes
* end repeat
*
*
* For PAX Format 0.1, the sparse headers are stored in a single variable : GNU.sparse.map
*
*
* GNU.sparse.map: Map of non-null data chunks. It is a string consisting of comma-separated values "offset,size[,offset-1,size-1...]"
*
*
* @param inputStream input stream to read keys and values
* @param sparseHeaders used in PAX Format 0.0 & 0.1, as it may appear multiple times, the sparse headers need to be stored in an array, not a map
* @param globalPaxHeaders global PAX headers of the tar archive
* @param headerSize total size of the PAX header, will be ignored if negative
* @return map of PAX headers values found inside the current (local or global) PAX headers tar entry.
* @throws IOException if an I/O error occurs.
* @since 1.21
*/
protected static Map parsePaxHeaders(final InputStream inputStream, final List sparseHeaders,
final Map globalPaxHeaders, final long headerSize) throws IOException {
final Map headers = new HashMap<>(globalPaxHeaders);
Long offset = null;
// Format is "length keyword=value\n";
int totalRead = 0;
while (true) { // get length
int ch;
int len = 0;
int read = 0;
while ((ch = inputStream.read()) != -1) {
read++;
totalRead++;
if (ch == '\n') { // blank line in header
break;
}
if (ch == ' ') { // End of length string
// Get keyword
final ByteArrayOutputStream coll = new ByteArrayOutputStream();
while ((ch = inputStream.read()) != -1) {
read++;
totalRead++;
if (totalRead < 0 || headerSize >= 0 && totalRead >= headerSize) {
break;
}
if (ch == '=') { // end of keyword
final String keyword = coll.toString(StandardCharsets.UTF_8);
// Get rest of entry
final int restLen = len - read;
if (restLen <= 1) { // only NL
headers.remove(keyword);
} else if (headerSize >= 0 && restLen > headerSize - totalRead) {
throw new IOException("Paxheader value size " + restLen + " exceeds size of header record");
} else {
final byte[] rest = IOUtils.readRange(inputStream, restLen);
final int got = rest.length;
if (got != restLen) {
throw new IOException("Failed to read Paxheader. Expected " + restLen + " bytes, read " + got);
}
totalRead += restLen;
// Drop trailing NL
if (rest[restLen - 1] != '\n') {
throw new IOException("Failed to read Paxheader." + "Value should end with a newline");
}
final String value = new String(rest, 0, restLen - 1, StandardCharsets.UTF_8);
headers.put(keyword, value);
// for 0.0 PAX Headers
if (keyword.equals(TarGnuSparseKeys.OFFSET)) {
if (offset != null) {
// previous GNU.sparse.offset header but no numBytes
sparseHeaders.add(new TarArchiveStructSparse(offset, 0));
}
try {
offset = Long.valueOf(value);
} catch (final NumberFormatException ex) {
throw new IOException("Failed to read Paxheader." + TarGnuSparseKeys.OFFSET + " contains a non-numeric value");
}
if (offset < 0) {
throw new IOException("Failed to read Paxheader." + TarGnuSparseKeys.OFFSET + " contains negative value");
}
}
// for 0.0 PAX Headers
if (keyword.equals(TarGnuSparseKeys.NUMBYTES)) {
if (offset == null) {
throw new IOException(
"Failed to read Paxheader." + TarGnuSparseKeys.OFFSET + " is expected before GNU.sparse.numbytes shows up.");
}
final long numbytes = ParsingUtils.parseLongValue(value);
if (numbytes < 0) {
throw new IOException("Failed to read Paxheader." + TarGnuSparseKeys.NUMBYTES + " contains negative value");
}
sparseHeaders.add(new TarArchiveStructSparse(offset, numbytes));
offset = null;
}
}
break;
}
coll.write((byte) ch);
}
break; // Processed single header
}
// COMPRESS-530 : throw if we encounter a non-number while reading length
if (ch < '0' || ch > '9') {
throw new IOException("Failed to read Paxheader. Encountered a non-number while reading length");
}
len *= 10;
len += ch - '0';
}
if (ch == -1) { // EOF
break;
}
}
if (offset != null) {
// offset but no numBytes
sparseHeaders.add(new TarArchiveStructSparse(offset, 0));
}
return headers;
}
/**
* Parses the content of a PAX 1.0 sparse block.
*
* @since 1.20
* @param buffer The buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @return a parsed sparse struct
*/
public static TarArchiveStructSparse parseSparse(final byte[] buffer, final int offset) {
final long sparseOffset = parseOctalOrBinary(buffer, offset, TarConstants.SPARSE_OFFSET_LEN);
final long sparseNumbytes = parseOctalOrBinary(buffer, offset + TarConstants.SPARSE_OFFSET_LEN, TarConstants.SPARSE_NUMBYTES_LEN);
return new TarArchiveStructSparse(sparseOffset, sparseNumbytes);
}
/**
* For 1.X PAX Format, the sparse headers are stored in the file data block, preceding the actual file data. It consists of a series of decimal numbers
* delimited by newlines.
*
* @param inputStream the input stream of the tar file
* @return the decimal number delimited by '\n', and the bytes read from input stream
* @throws IOException
*/
private static long[] readLineOfNumberForPax1X(final InputStream inputStream) throws IOException {
int number;
long result = 0;
long bytesRead = 0;
while ((number = inputStream.read()) != '\n') {
bytesRead += 1;
if (number == -1) {
throw new IOException("Unexpected EOF when reading parse information of 1.X PAX format");
}
if (number < '0' || number > '9') {
throw new IOException("Corrupted TAR archive. Non-numeric value in sparse headers block");
}
result = result * 10 + (number - '0');
}
bytesRead += 1;
return new long[] { result, bytesRead };
}
/**
* @since 1.21
*/
static List readSparseStructs(final byte[] buffer, final int offset, final int entries) throws IOException {
final List sparseHeaders = new ArrayList<>();
for (int i = 0; i < entries; i++) {
try {
final TarArchiveStructSparse sparseHeader = parseSparse(buffer,
offset + i * (TarConstants.SPARSE_OFFSET_LEN + TarConstants.SPARSE_NUMBYTES_LEN));
if (sparseHeader.getOffset() < 0) {
throw new IOException("Corrupted TAR archive, sparse entry with negative offset");
}
if (sparseHeader.getNumbytes() < 0) {
throw new IOException("Corrupted TAR archive, sparse entry with negative numbytes");
}
sparseHeaders.add(sparseHeader);
} catch (final IllegalArgumentException ex) {
// thrown internally by parseOctalOrBinary
throw new IOException("Corrupted TAR archive, sparse entry is invalid", ex);
}
}
return Collections.unmodifiableList(sparseHeaders);
}
/**
* Wikipedia says: The checksum is calculated by taking the sum of the
* unsigned byte values of the header block with the eight checksum bytes taken to be ASCII spaces (decimal value 32). It is stored as a six digit octal
* number with leading zeroes followed by a NUL and then a space. Various implementations do not adhere to this format. For better compatibility, ignore
* leading and trailing whitespace, and get the first six digits. In addition, some historic tar implementations treated bytes as signed. Implementations
* typically calculate the checksum both ways, and treat it as good if either the signed or unsigned sum matches the included checksum.
*
* The return value of this method should be treated as a best-effort heuristic rather than an absolute and final truth. The checksum verification logic may
* well evolve over time as more special cases are encountered.
*
*
* @param header tar header
* @return whether the checksum is reasonably good
* @see COMPRESS-191
* @since 1.5
*/
public static boolean verifyCheckSum(final byte[] header) {
final long storedSum = parseOctal(header, TarConstants.CHKSUM_OFFSET, TarConstants.CHKSUMLEN);
long unsignedSum = 0;
long signedSum = 0;
for (int i = 0; i < header.length; i++) {
byte b = header[i];
if (TarConstants.CHKSUM_OFFSET <= i && i < TarConstants.CHKSUM_OFFSET + TarConstants.CHKSUMLEN) {
b = ' ';
}
unsignedSum += 0xff & b;
signedSum += b;
}
return storedSum == unsignedSum || storedSum == signedSum;
}
/** Prevents instantiation. */
private TarUtils() {
}
}