    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.HashMap;
    026import java.util.Map;
    027import java.util.PriorityQueue;
    028import java.util.Queue;
    029import java.util.Stack;
    030
    031import org.apache.commons.compress.archivers.ArchiveException;
    032import org.apache.commons.compress.archivers.ArchiveInputStream;
    033import org.apache.commons.compress.archivers.zip.ZipEncoding;
    034import org.apache.commons.compress.archivers.zip.ZipEncodingHelper;
    035import org.apache.commons.compress.utils.IOUtils;
    036
    037/**
    038 * The DumpArchiveInputStream reads a UNIX dump archive as an InputStream.
    039 * Methods are provided to position at each successive entry in
    040 * the archive, and the read each entry as a normal input stream
    041 * using read().
    042 *
    043 * There doesn't seem to exist a hint on the encoding of string values
    044 * in any piece documentation.  Given the main purpose of dump/restore
    045 * is backing up a system it seems very likely the format uses the
    046 * current default encoding of the system.
    047 *
    048 * @NotThreadSafe
    049 */
    050public class DumpArchiveInputStream extends ArchiveInputStream {
    051    /**
    052     * Look at the first few bytes of the file to decide if it's a dump
    053     * archive. With 32 bytes we can look at the magic value, with a full
    054     * 1k we can verify the checksum.
    055     * @param buffer data to match
    056     * @param length length of data
    057     * @return whether the buffer seems to contain dump data
    058     */
    059    public static boolean matches(final byte[] buffer, final int length) {
    060        // do we have enough of the header?
    061        if (length < 32) {
    062            return false;
    063        }
    064
    065        // this is the best test
    066        if (length >= DumpArchiveConstants.TP_SIZE) {
    067            return DumpArchiveUtil.verify(buffer);
    068        }
    069
    070        // this will work in a pinch.
    071        return DumpArchiveConstants.NFS_MAGIC == DumpArchiveUtil.convert32(buffer,
    072            24);
    073    }
    074    private final DumpArchiveSummary summary;
    075    private DumpArchiveEntry active;
    076    private boolean isClosed;
    077    private boolean hasHitEOF;
    078    private long entrySize;
    079    private long entryOffset;
    080    private int readIdx;
    081    private final byte[] readBuf = new byte[DumpArchiveConstants.TP_SIZE];
    082    private byte[] blockBuffer;
    083    private int recordOffset;
    084    private long filepos;
    085
    086    protected TapeInputStream raw;
    087
    088    // map of ino -> dirent entry. We can use this to reconstruct full paths.
    089    private final Map<Integer, Dirent> names = new HashMap<>();
    090
    091    // map of ino -> (directory) entry when we're missing one or more elements in the path.
    092    private final Map<Integer, DumpArchiveEntry> pending = new HashMap<>();
    093
    094    // queue of (directory) entries where we now have the full path.
    095    private final Queue<DumpArchiveEntry> queue;
    096
    097    /**
    098     * The encoding to use for file names and labels.
    099     */
    100    private final ZipEncoding zipEncoding;
    101
    102    // the provided encoding (for unit tests)
    103    final String encoding;
    104
    105    /**
    106     * Constructor using the platform's default encoding for file
    107     * names.
    108     *
    109     * @param is stream to read from
    110     * @throws ArchiveException on error
    111     */
    112    public DumpArchiveInputStream(final InputStream is) throws ArchiveException {
    113        this(is, null);
    114    }
    115
    116    /**
    117     * Constructor.
    118     *
    119     * @param is stream to read from
    120     * @param encoding the encoding to use for file names, use null
    121     * for the platform's default encoding
    122     * @since 1.6
    123     * @throws ArchiveException on error
    124     */
    125    public DumpArchiveInputStream(final InputStream is, final String encoding)
    126        throws ArchiveException {
    127        this.raw = new TapeInputStream(is);
    128        this.hasHitEOF = false;
    129        this.encoding = encoding;
    130        this.zipEncoding = ZipEncodingHelper.getZipEncoding(encoding);
    131
    132        try {
    133            // read header, verify it's a dump archive.
    134            final byte[] headerBytes = raw.readRecord();
    135
    136            if (!DumpArchiveUtil.verify(headerBytes)) {
    137                throw new UnrecognizedFormatException();
    138            }
    139
    140            // get summary information
    141            summary = new DumpArchiveSummary(headerBytes, this.zipEncoding);
    142
    143            // reset buffer with actual block size.
    144            raw.resetBlockSize(summary.getNTRec(), summary.isCompressed());
    145
    146            // allocate our read buffer.
    147            blockBuffer = new byte[4 * DumpArchiveConstants.TP_SIZE];
    148
    149            // skip past CLRI and BITS segments since we don't handle them yet.
    150            readCLRI();
    151            readBITS();
    152        } catch (final IOException ex) {
    153            throw new ArchiveException(ex.getMessage(), ex);
    154        }
    155
    156        // put in a dummy record for the root node.
    157        final Dirent root = new Dirent(2, 2, 4, ".");
    158        names.put(2, root);
    159
    160        // use priority based on queue to ensure parent directories are
    161        // released first.
    162        queue = new PriorityQueue<>(10,
    163                (p, q) -> {
    164                    if (p.getOriginalName() == null || q.getOriginalName() == null) {
    165                        return Integer.MAX_VALUE;
    166                    }
    167
    168                    return p.getOriginalName().compareTo(q.getOriginalName());
    169                });
    170    }
    171
    172    /**
    173     * Closes the stream for this entry.
    174     */
    175    @Override
    176    public void close() throws IOException {
    177        if (!isClosed) {
    178            isClosed = true;
    179            raw.close();
    180        }
    181    }
    182
    183    @Override
    184    public long getBytesRead() {
    185        return raw.getBytesRead();
    186    }
    187
    188    @Deprecated
    189    @Override
    190    public int getCount() {
    191        return (int) getBytesRead();
    192    }
    193
    194    /**
    195     * Read the next entry.
    196     * @return the next entry
    197     * @throws IOException on error
    198     */
    199    public DumpArchiveEntry getNextDumpEntry() throws IOException {
    200        return getNextEntry();
    201    }
    202
    203    @Override
    204    public DumpArchiveEntry getNextEntry() throws IOException {
    205        DumpArchiveEntry entry = null;
    206        String path = null;
    207
    208        // is there anything in the queue?
    209        if (!queue.isEmpty()) {
    210            return queue.remove();
    211        }
    212
    213        while (entry == null) {
    214            if (hasHitEOF) {
    215                return null;
    216            }
    217
    218            // skip any remaining records in this segment for prior file.
    219            // we might still have holes... easiest to do it
    220            // block by block. We may want to revisit this if
    221            // the unnecessary decompression time adds up.
    222            while (readIdx < active.getHeaderCount()) {
    223                if (!active.isSparseRecord(readIdx++)
    224                    && raw.skip(DumpArchiveConstants.TP_SIZE) == -1) {
    225                    throw new EOFException();
    226                }
    227            }
    228
    229            readIdx = 0;
    230            filepos = raw.getBytesRead();
    231
    232            byte[] headerBytes = raw.readRecord();
    233
    234            if (!DumpArchiveUtil.verify(headerBytes)) {
    235                throw new InvalidFormatException();
    236            }
    237
    238            active = DumpArchiveEntry.parse(headerBytes);
    239
    240            // skip any remaining segments for prior file.
    241            while (DumpArchiveConstants.SEGMENT_TYPE.ADDR == active.getHeaderType()) {
    242                if (raw.skip((long) DumpArchiveConstants.TP_SIZE
    243                             * (active.getHeaderCount()
    244                                - active.getHeaderHoles())) == -1) {
    245                    throw new EOFException();
    246                }
    247
    248                filepos = raw.getBytesRead();
    249                headerBytes = raw.readRecord();
    250
    251                if (!DumpArchiveUtil.verify(headerBytes)) {
    252                    throw new InvalidFormatException();
    253                }
    254
    255                active = DumpArchiveEntry.parse(headerBytes);
    256            }
    257
    258            // check if this is an end-of-volume marker.
    259            if (DumpArchiveConstants.SEGMENT_TYPE.END == active.getHeaderType()) {
    260                hasHitEOF = true;
    261
    262                return null;
    263            }
    264
    265            entry = active;
    266
    267            if (entry.isDirectory()) {
    268                readDirectoryEntry(active);
    269
    270                // now we create an empty InputStream.
    271                entryOffset = 0;
    272                entrySize = 0;
    273                readIdx = active.getHeaderCount();
    274            } else {
    275                entryOffset = 0;
    276                entrySize = active.getEntrySize();
    277                readIdx = 0;
    278            }
    279
    280            recordOffset = readBuf.length;
    281
    282            path = getPath(entry);
    283
    284            if (path == null) {
    285                entry = null;
    286            }
    287        }
    288
    289        entry.setName(path);
    290        entry.setSimpleName(names.get(entry.getIno()).getName());
    291        entry.setOffset(filepos);
    292
    293        return entry;
    294    }
    295
    296    /**
    297     * Get full path for specified archive entry, or null if there's a gap.
    298     *
    299     * @param entry
    300     * @return  full path for specified archive entry, or null if there's a gap.
    301     */
    302    private String getPath(final DumpArchiveEntry entry) {
    303        // build the stack of elements. It's possible that we're
    304        // still missing an intermediate value and if so we
    305        final Stack<String> elements = new Stack<>();
    306        Dirent dirent = null;
    307
    308        for (int i = entry.getIno();; i = dirent.getParentIno()) {
    309            if (!names.containsKey(i)) {
    310                elements.clear();
    311                break;
    312            }
    313
    314            dirent = names.get(i);
    315            elements.push(dirent.getName());
    316
    317            if (dirent.getIno() == dirent.getParentIno()) {
    318                break;
    319            }
    320        }
    321
    322        // if an element is missing defer the work and read next entry.
    323        if (elements.isEmpty()) {
    324            pending.put(entry.getIno(), entry);
    325
    326            return null;
    327        }
    328
    329        // generate full path from stack of elements.
    330        final StringBuilder sb = new StringBuilder(elements.pop());
    331
    332        while (!elements.isEmpty()) {
    333            sb.append('/');
    334            sb.append(elements.pop());
    335        }
    336
    337        return sb.toString();
    338    }
    339
    340    /**
    341     * Return the archive summary information.
    342     * @return the summary
    343     */
    344    public DumpArchiveSummary getSummary() {
    345        return summary;
    346    }
    347
    348    /**
    349     * Reads bytes from the current dump archive entry.
    350     *
    351     * This method is aware of the boundaries of the current
    352     * entry in the archive and will deal with them as if they
    353     * were this stream's start and EOF.
    354     *
    355     * @param buf The buffer into which to place bytes read.
    356     * @param off The offset at which to place bytes read.
    357     * @param len The number of bytes to read.
    358     * @return The number of bytes read, or -1 at EOF.
    359     * @throws IOException on error
    360     */
    361    @Override
    362    public int read(final byte[] buf, int off, int len) throws IOException {
    363        if (len == 0) {
    364            return 0;
    365        }
    366        int totalRead = 0;
    367
    368        if (hasHitEOF || isClosed || entryOffset >= entrySize) {
    369            return -1;
    370        }
    371
    372        if (active == null) {
    373            throw new IllegalStateException("No current dump entry");
    374        }
    375
    376        if (len + entryOffset > entrySize) {
    377            len = (int) (entrySize - entryOffset);
    378        }
    379
    380        while (len > 0) {
    381            final int sz = Math.min(len, readBuf.length - recordOffset);
    382
    383            // copy any data we have
    384            if (recordOffset + sz <= readBuf.length) {
    385                System.arraycopy(readBuf, recordOffset, buf, off, sz);
    386                totalRead += sz;
    387                recordOffset += sz;
    388                len -= sz;
    389                off += sz;
    390            }
    391
    392            // load next block if necessary.
    393            if (len > 0) {
    394                if (readIdx >= 512) {
    395                    final byte[] headerBytes = raw.readRecord();
    396
    397                    if (!DumpArchiveUtil.verify(headerBytes)) {
    398                        throw new InvalidFormatException();
    399                    }
    400
    401                    active = DumpArchiveEntry.parse(headerBytes);
    402                    readIdx = 0;
    403                }
    404
    405                if (!active.isSparseRecord(readIdx++)) {
    406                    final int r = raw.read(readBuf, 0, readBuf.length);
    407                    if (r != readBuf.length) {
    408                        throw new EOFException();
    409                    }
    410                } else {
    411                    Arrays.fill(readBuf, (byte) 0);
    412                }
    413
    414                recordOffset = 0;
    415            }
    416        }
    417
    418        entryOffset += totalRead;
    419
    420        return totalRead;
    421    }
    422
    423    /**
    424     * Read BITS segment.
    425     */
    426    private void readBITS() throws IOException {
    427        final byte[] buffer = raw.readRecord();
    428
    429        if (!DumpArchiveUtil.verify(buffer)) {
    430            throw new InvalidFormatException();
    431        }
    432
    433        active = DumpArchiveEntry.parse(buffer);
    434
    435        if (DumpArchiveConstants.SEGMENT_TYPE.BITS != active.getHeaderType()) {
    436            throw new InvalidFormatException();
    437        }
    438
    439        // we don't do anything with this yet.
    440        if (raw.skip((long) DumpArchiveConstants.TP_SIZE * active.getHeaderCount())
    441            == -1) {
    442            throw new EOFException();
    443        }
    444        readIdx = active.getHeaderCount();
    445    }
    446
    447    /**
    448     * Read CLRI (deleted inode) segment.
    449     */
    450    private void readCLRI() throws IOException {
    451        final byte[] buffer = raw.readRecord();
    452
    453        if (!DumpArchiveUtil.verify(buffer)) {
    454            throw new InvalidFormatException();
    455        }
    456
    457        active = DumpArchiveEntry.parse(buffer);
    458
    459        if (DumpArchiveConstants.SEGMENT_TYPE.CLRI != active.getHeaderType()) {
    460            throw new InvalidFormatException();
    461        }
    462
    463        // we don't do anything with this yet.
    464        if (raw.skip((long) DumpArchiveConstants.TP_SIZE * active.getHeaderCount())
    465            == -1) {
    466            throw new EOFException();
    467        }
    468        readIdx = active.getHeaderCount();
    469    }
    470
    471    /**
    472     * Read directory entry.
    473     */
    474    private void readDirectoryEntry(DumpArchiveEntry entry)
    475        throws IOException {
    476        long size = entry.getEntrySize();
    477        boolean first = true;
    478
    479        while (first ||
    480                DumpArchiveConstants.SEGMENT_TYPE.ADDR == entry.getHeaderType()) {
    481            // read the header that we just peeked at.
    482            if (!first) {
    483                raw.readRecord();
    484            }
    485
    486            if (!names.containsKey(entry.getIno()) &&
    487                    DumpArchiveConstants.SEGMENT_TYPE.INODE == entry.getHeaderType()) {
    488                pending.put(entry.getIno(), entry);
    489            }
    490
    491            final int datalen = DumpArchiveConstants.TP_SIZE * entry.getHeaderCount();
    492
    493            if (blockBuffer.length < datalen) {
    494                blockBuffer = IOUtils.readRange(raw, datalen);
    495                if (blockBuffer.length != datalen) {
    496                    throw new EOFException();
    497                }
    498            } else if (raw.read(blockBuffer, 0, datalen) != datalen) {
    499                throw new EOFException();
    500            }
    501
    502            int reclen = 0;
    503
    504            for (int i = 0; i < datalen - 8 && i < size - 8;
    505                    i += reclen) {
    506                final int ino = DumpArchiveUtil.convert32(blockBuffer, i);
    507                reclen = DumpArchiveUtil.convert16(blockBuffer, i + 4);
    508
    509                final byte type = blockBuffer[i + 6];
    510
    511                final String name = DumpArchiveUtil.decode(zipEncoding, blockBuffer, i + 8, blockBuffer[i + 7]);
    512
    513                if (".".equals(name) || "..".equals(name)) {
    514                    // do nothing...
    515                    continue;
    516                }
    517
    518                final Dirent d = new Dirent(ino, entry.getIno(), type, name);
    519
    520                /*
    521                if ((type == 4) && names.containsKey(ino)) {
    522                    System.out.println("we already have ino: " +
    523                                       names.get(ino));
    524                }
    525                */
    526
    527                names.put(ino, d);
    528
    529                // check whether this allows us to fill anything in the pending list.
    530                pending.forEach((k, v) -> {
    531                    final String path = getPath(v);
    532
    533                    if (path != null) {
    534                        v.setName(path);
    535                        v.setSimpleName(names.get(k).getName());
    536                        queue.add(v);
    537                    }
    538                });
    539
    540                // remove anything that we found. (We can't do it earlier
    541                // because of concurrent modification exceptions.)
    542                queue.forEach(e -> pending.remove(e.getIno()));
    543            }
    544
    545            final byte[] peekBytes = raw.peek();
    546
    547            if (!DumpArchiveUtil.verify(peekBytes)) {
    548                throw new InvalidFormatException();
    549            }
    550
    551            entry = DumpArchiveEntry.parse(peekBytes);
    552            first = false;
    553            size -= DumpArchiveConstants.TP_SIZE;
    554        }
    555    }
    556
    557}