    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 * http://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.commons.compress.archivers.dump;
    020
    021import java.io.EOFException;
    022import java.io.IOException;
    023import java.io.InputStream;
    024import java.util.Arrays;
    025import java.util.BitSet;
    026import java.util.HashMap;
    027import java.util.Map;
    028import java.util.PriorityQueue;
    029import java.util.Queue;
    030import java.util.Stack;
    031
    032import org.apache.commons.compress.archivers.ArchiveException;
    033import org.apache.commons.compress.archivers.ArchiveInputStream;
    034import org.apache.commons.compress.archivers.zip.ZipEncoding;
    035import org.apache.commons.compress.archivers.zip.ZipEncodingHelper;
    036import org.apache.commons.compress.utils.IOUtils;
    037
    038/**
    039 * The DumpArchiveInputStream reads a UNIX dump archive as an InputStream. Methods are provided to position at each successive entry in the archive, and the
    040 * read each entry as a normal input stream using read().
    041 * <p>
    042 * There doesn't seem to exist a hint on the encoding of string values in any piece documentation. Given the main purpose of dump/restore is backing up a system
    043 * it seems very likely the format uses the current default encoding of the system.
    044 * </p>
    045 * @NotThreadSafe
    046 * @since 1.3
    047 */
    048public class DumpArchiveInputStream extends ArchiveInputStream<DumpArchiveEntry> {
    049
    050    private static final String CURRENT_PATH_SEGMENT = ".";
    051    private static final String PARENT_PATH_SEGMENT = "..";
    052
    053    /**
    054     * Look at the first few bytes of the file to decide if it's a dump archive. With 32 bytes we can look at the magic value, with a full 1k we can verify the
    055     * checksum.
    056     *
    057     * @param buffer data to match
    058     * @param length length of data
    059     * @return whether the buffer seems to contain dump data
    060     */
    061    public static boolean matches(final byte[] buffer, final int length) {
    062        // do we have enough of the header?
    063        if (length < 32) {
    064            return false;
    065        }
    066
    067        // this is the best test
    068        if (length >= DumpArchiveConstants.TP_SIZE) {
    069            return DumpArchiveUtil.verify(buffer);
    070        }
    071
    072        // this will work in a pinch.
    073        return DumpArchiveConstants.NFS_MAGIC == DumpArchiveUtil.convert32(buffer, 24);
    074    }
    075
    076    private final DumpArchiveSummary summary;
    077    private DumpArchiveEntry active;
    078    private boolean isClosed;
    079    private boolean hasHitEOF;
    080    private long entrySize;
    081    private long entryOffset;
    082    private int readIdx;
    083    private final byte[] readBuf = new byte[DumpArchiveConstants.TP_SIZE];
    084    private byte[] blockBuffer;
    085    private int recordOffset;
    086    private long filepos;
    087
    088    protected TapeInputStream raw;
    089
    090    /** Map of ino -> dirent entry. We can use this to reconstruct full paths. */
    091    private final Map<Integer, Dirent> names = new HashMap<>();
    092
    093    /** Map of ino -> (directory) entry when we're missing one or more elements in the path. */
    094    private final Map<Integer, DumpArchiveEntry> pending = new HashMap<>();
    095
    096    /** Queue of (directory) entries where we now have the full path. */
    097    private final Queue<DumpArchiveEntry> queue;
    098
    099    /**
    100     * The encoding to use for file names and labels.
    101     */
    102    private final ZipEncoding zipEncoding;
    103
    104    /**
    105     * Constructor using the platform's default encoding for file names.
    106     *
    107     * @param is stream to read from
    108     * @throws ArchiveException on error
    109     */
    110    public DumpArchiveInputStream(final InputStream is) throws ArchiveException {
    111        this(is, null);
    112    }
    113
    114    /**
    115     * Constructs a new instance.
    116     *
    117     * @param is       stream to read from
    118     * @param encoding the encoding to use for file names, use null for the platform's default encoding
    119     * @since 1.6
    120     * @throws ArchiveException on error
    121     */
    122    public DumpArchiveInputStream(final InputStream is, final String encoding) throws ArchiveException {
    123        super(is, encoding);
    124        this.raw = new TapeInputStream(is);
    125        this.hasHitEOF = false;
    126        this.zipEncoding = ZipEncodingHelper.getZipEncoding(encoding);
    127
    128        try {
    129            // read header, verify it's a dump archive.
    130            final byte[] headerBytes = raw.readRecord();
    131
    132            if (!DumpArchiveUtil.verify(headerBytes)) {
    133                throw new UnrecognizedFormatException();
    134            }
    135
    136            // get summary information
    137            summary = new DumpArchiveSummary(headerBytes, this.zipEncoding);
    138
    139            // reset buffer with actual block size.
    140            raw.resetBlockSize(summary.getNTRec(), summary.isCompressed());
    141
    142            // allocate our read buffer.
    143            blockBuffer = new byte[4 * DumpArchiveConstants.TP_SIZE];
    144
    145            // skip past CLRI and BITS segments since we don't handle them yet.
    146            readCLRI();
    147            readBITS();
    148        } catch (final IOException ex) {
    149            throw new ArchiveException(ex.getMessage(), ex);
    150        }
    151
    152        // put in a dummy record for the root node.
    153        final Dirent root = new Dirent(2, 2, 4, CURRENT_PATH_SEGMENT);
    154        names.put(2, root);
    155
    156        // use priority based on queue to ensure parent directories are
    157        // released first.
    158        queue = new PriorityQueue<>(10, (p, q) -> {
    159            if (p.getOriginalName() == null || q.getOriginalName() == null) {
    160                return Integer.MAX_VALUE;
    161            }
    162
    163            return p.getOriginalName().compareTo(q.getOriginalName());
    164        });
    165    }
    166
    167    /**
    168     * Closes the stream for this entry.
    169     */
    170    @Override
    171    public void close() throws IOException {
    172        if (!isClosed) {
    173            isClosed = true;
    174            raw.close();
    175        }
    176    }
    177
    178    @Override
    179    public long getBytesRead() {
    180        return raw.getBytesRead();
    181    }
    182
    183    @Deprecated
    184    @Override
    185    public int getCount() {
    186        return (int) getBytesRead();
    187    }
    188
    189    /**
    190     * Reads the next entry.
    191     *
    192     * @return the next entry
    193     * @throws IOException on error
    194     * @deprecated Use {@link #getNextEntry()}.
    195     */
    196    @Deprecated
    197    public DumpArchiveEntry getNextDumpEntry() throws IOException {
    198        return getNextEntry();
    199    }
    200
    201    @Override
    202    public DumpArchiveEntry getNextEntry() throws IOException {
    203        DumpArchiveEntry entry = null;
    204        String path = null;
    205
    206        // is there anything in the queue?
    207        if (!queue.isEmpty()) {
    208            return queue.remove();
    209        }
    210
    211        while (entry == null) {
    212            if (hasHitEOF) {
    213                return null;
    214            }
    215
    216            // skip any remaining records in this segment for prior file.
    217            // we might still have holes... easiest to do it
    218            // block by block. We may want to revisit this if
    219            // the unnecessary decompression time adds up.
    220            while (readIdx < active.getHeaderCount()) {
    221                if (!active.isSparseRecord(readIdx++) && raw.skip(DumpArchiveConstants.TP_SIZE) == -1) {
    222                    throw new EOFException();
    223                }
    224            }
    225
    226            readIdx = 0;
    227            filepos = raw.getBytesRead();
    228
    229            byte[] headerBytes = raw.readRecord();
    230
    231            if (!DumpArchiveUtil.verify(headerBytes)) {
    232                throw new InvalidFormatException();
    233            }
    234
    235            active = DumpArchiveEntry.parse(headerBytes);
    236
    237            // skip any remaining segments for prior file.
    238            while (DumpArchiveConstants.SEGMENT_TYPE.ADDR == active.getHeaderType()) {
    239                if (raw.skip((long) DumpArchiveConstants.TP_SIZE * (active.getHeaderCount() - active.getHeaderHoles())) == -1) {
    240                    throw new EOFException();
    241                }
    242
    243                filepos = raw.getBytesRead();
    244                headerBytes = raw.readRecord();
    245
    246                if (!DumpArchiveUtil.verify(headerBytes)) {
    247                    throw new InvalidFormatException();
    248                }
    249
    250                active = DumpArchiveEntry.parse(headerBytes);
    251            }
    252
    253            // check if this is an end-of-volume marker.
    254            if (DumpArchiveConstants.SEGMENT_TYPE.END == active.getHeaderType()) {
    255                hasHitEOF = true;
    256
    257                return null;
    258            }
    259
    260            entry = active;
    261
    262            if (entry.isDirectory()) {
    263                readDirectoryEntry(active);
    264
    265                // now we create an empty InputStream.
    266                entryOffset = 0;
    267                entrySize = 0;
    268                readIdx = active.getHeaderCount();
    269            } else {
    270                entryOffset = 0;
    271                entrySize = active.getEntrySize();
    272                readIdx = 0;
    273            }
    274
    275            recordOffset = readBuf.length;
    276
    277            path = getPath(entry);
    278
    279            if (path == null) {
    280                entry = null;
    281            }
    282        }
    283
    284        entry.setName(path);
    285        entry.setSimpleName(names.get(entry.getIno()).getName());
    286        entry.setOffset(filepos);
    287
    288        return entry;
    289    }
    290
    291    /**
    292     * Gets full path for specified archive entry, or null if there's a gap.
    293     *
    294     * @param entry
    295     * @return full path for specified archive entry, or null if there's a gap.
    296     * @throws DumpArchiveException Infinite loop detected in directory entries.
    297     */
    298    private String getPath(final DumpArchiveEntry entry) throws DumpArchiveException {
    299        // build the stack of elements. It's possible that we're
    300        // still missing an intermediate value and if so we
    301        final Stack<String> elements = new Stack<>();
    302        final BitSet visited = new BitSet();
    303        Dirent dirent = null;
    304        for (int i = entry.getIno();; i = dirent.getParentIno()) {
    305            if (!names.containsKey(i)) {
    306                elements.clear();
    307                break;
    308            }
    309            if (visited.get(i)) {
    310                throw new DumpArchiveException("Duplicate node " + i);
    311            }
    312            dirent = names.get(i);
    313            visited.set(i);
    314            elements.push(dirent.getName());
    315            if (dirent.getIno() == dirent.getParentIno()) {
    316                break;
    317            }
    318        }
    319        // if an element is missing defer the work and read next entry.
    320        if (elements.isEmpty()) {
    321            pending.put(entry.getIno(), entry);
    322            return null;
    323        }
    324        // generate full path from stack of elements.
    325        final StringBuilder sb = new StringBuilder(elements.pop());
    326        while (!elements.isEmpty()) {
    327            sb.append('/');
    328            sb.append(elements.pop());
    329        }
    330        return sb.toString();
    331    }
    332
    333    /**
    334     * Gets the archive summary information.
    335     *
    336     * @return the summary
    337     */
    338    public DumpArchiveSummary getSummary() {
    339        return summary;
    340    }
    341
    342    /**
    343     * Reads bytes from the current dump archive entry.
    344     *
    345     * This method is aware of the boundaries of the current entry in the archive and will deal with them as if they were this stream's start and EOF.
    346     *
    347     * @param buf The buffer into which to place bytes read.
    348     * @param off The offset at which to place bytes read.
    349     * @param len The number of bytes to read.
    350     * @return The number of bytes read, or -1 at EOF.
    351     * @throws IOException on error
    352     */
    353    @Override
    354    public int read(final byte[] buf, int off, int len) throws IOException {
    355        if (len == 0) {
    356            return 0;
    357        }
    358        int totalRead = 0;
    359
    360        if (hasHitEOF || isClosed || entryOffset >= entrySize) {
    361            return -1;
    362        }
    363
    364        if (active == null) {
    365            throw new IllegalStateException("No current dump entry");
    366        }
    367
    368        if (len + entryOffset > entrySize) {
    369            len = (int) (entrySize - entryOffset);
    370        }
    371
    372        while (len > 0) {
    373            final int sz = Math.min(len, readBuf.length - recordOffset);
    374
    375            // copy any data we have
    376            if (recordOffset + sz <= readBuf.length) {
    377                System.arraycopy(readBuf, recordOffset, buf, off, sz);
    378                totalRead += sz;
    379                recordOffset += sz;
    380                len -= sz;
    381                off += sz;
    382            }
    383
    384            // load next block if necessary.
    385            if (len > 0) {
    386                if (readIdx >= 512) {
    387                    final byte[] headerBytes = raw.readRecord();
    388
    389                    if (!DumpArchiveUtil.verify(headerBytes)) {
    390                        throw new InvalidFormatException();
    391                    }
    392
    393                    active = DumpArchiveEntry.parse(headerBytes);
    394                    readIdx = 0;
    395                }
    396
    397                if (!active.isSparseRecord(readIdx++)) {
    398                    final int r = raw.read(readBuf, 0, readBuf.length);
    399                    if (r != readBuf.length) {
    400                        throw new EOFException();
    401                    }
    402                } else {
    403                    Arrays.fill(readBuf, (byte) 0);
    404                }
    405
    406                recordOffset = 0;
    407            }
    408        }
    409
    410        entryOffset += totalRead;
    411
    412        return totalRead;
    413    }
    414
    415    /**
    416     * Read BITS segment.
    417     */
    418    private void readBITS() throws IOException {
    419        final byte[] buffer = raw.readRecord();
    420
    421        if (!DumpArchiveUtil.verify(buffer)) {
    422            throw new InvalidFormatException();
    423        }
    424
    425        active = DumpArchiveEntry.parse(buffer);
    426
    427        if (DumpArchiveConstants.SEGMENT_TYPE.BITS != active.getHeaderType()) {
    428            throw new InvalidFormatException();
    429        }
    430
    431        // we don't do anything with this yet.
    432        if (raw.skip((long) DumpArchiveConstants.TP_SIZE * active.getHeaderCount()) == -1) {
    433            throw new EOFException();
    434        }
    435        readIdx = active.getHeaderCount();
    436    }
    437
    438    /**
    439     * Read CLRI (deleted inode) segment.
    440     */
    441    private void readCLRI() throws IOException {
    442        final byte[] buffer = raw.readRecord();
    443
    444        if (!DumpArchiveUtil.verify(buffer)) {
    445            throw new InvalidFormatException();
    446        }
    447
    448        active = DumpArchiveEntry.parse(buffer);
    449
    450        if (DumpArchiveConstants.SEGMENT_TYPE.CLRI != active.getHeaderType()) {
    451            throw new InvalidFormatException();
    452        }
    453
    454        // we don't do anything with this yet.
    455        if (raw.skip((long) DumpArchiveConstants.TP_SIZE * active.getHeaderCount()) == -1) {
    456            throw new EOFException();
    457        }
    458        readIdx = active.getHeaderCount();
    459    }
    460
    461    /**
    462     * Read directory entry.
    463     */
    464    private void readDirectoryEntry(DumpArchiveEntry entry) throws IOException {
    465        long size = entry.getEntrySize();
    466        boolean first = true;
    467
    468        while (first || DumpArchiveConstants.SEGMENT_TYPE.ADDR == entry.getHeaderType()) {
    469            // read the header that we just peeked at.
    470            if (!first) {
    471                raw.readRecord();
    472            }
    473
    474            if (!names.containsKey(entry.getIno()) && DumpArchiveConstants.SEGMENT_TYPE.INODE == entry.getHeaderType()) {
    475                pending.put(entry.getIno(), entry);
    476            }
    477
    478            final int datalen = DumpArchiveConstants.TP_SIZE * entry.getHeaderCount();
    479
    480            if (blockBuffer.length < datalen) {
    481                blockBuffer = IOUtils.readRange(raw, datalen);
    482                if (blockBuffer.length != datalen) {
    483                    throw new EOFException();
    484                }
    485            } else if (raw.read(blockBuffer, 0, datalen) != datalen) {
    486                throw new EOFException();
    487            }
    488
    489            int reclen = 0;
    490
    491            for (int i = 0; i < datalen - 8 && i < size - 8; i += reclen) {
    492                final int ino = DumpArchiveUtil.convert32(blockBuffer, i);
    493                reclen = DumpArchiveUtil.convert16(blockBuffer, i + 4);
    494                if (reclen == 0) {
    495                    throw new DumpArchiveException("reclen cannot be 0");
    496                }
    497
    498                final byte type = blockBuffer[i + 6];
    499
    500                final String name = DumpArchiveUtil.decode(zipEncoding, blockBuffer, i + 8, blockBuffer[i + 7]);
    501
    502                if (CURRENT_PATH_SEGMENT.equals(name) || PARENT_PATH_SEGMENT.equals(name)) {
    503                    // do nothing...
    504                    continue;
    505                }
    506
    507                final Dirent d = new Dirent(ino, entry.getIno(), type, name);
    508
    509                /*
    510                 * if ((type == 4) && names.containsKey(ino)) { System.out.println("we already have ino: " + names.get(ino)); }
    511                 */
    512
    513                names.put(ino, d);
    514
    515                // check whether this allows us to fill anything in the pending list.
    516                for (final Map.Entry<Integer, DumpArchiveEntry> mapEntry : pending.entrySet()) {
    517                    final DumpArchiveEntry v = mapEntry.getValue();
    518                    final String path = getPath(v);
    519                    if (path != null) {
    520                        v.setName(path);
    521                        v.setSimpleName(names.get(mapEntry.getKey()).getName());
    522                        queue.add(v);
    523                    }
    524                }
    525
    526                // remove anything that we found. (We can't do it earlier
    527                // because of concurrent modification exceptions.)
    528                queue.forEach(e -> pending.remove(e.getIno()));
    529            }
    530
    531            final byte[] peekBytes = raw.peek();
    532
    533            if (!DumpArchiveUtil.verify(peekBytes)) {
    534                throw new InvalidFormatException();
    535            }
    536
    537            entry = DumpArchiveEntry.parse(peekBytes);
    538            first = false;
    539            size -= DumpArchiveConstants.TP_SIZE;
    540        }
    541    }
    542
    543}