# Source code

    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 org.apache.commons.compress.archivers.ArchiveException;
    022import org.apache.commons.compress.archivers.ArchiveInputStream;
    023import org.apache.commons.compress.archivers.zip.ZipEncoding;
    024import org.apache.commons.compress.archivers.zip.ZipEncodingHelper;
    025
    026import java.io.EOFException;
    027import java.io.IOException;
    028import java.io.InputStream;
    029
    030import java.util.Arrays;
    031import java.util.Comparator;
    032import java.util.HashMap;
    033import java.util.Map;
    034import java.util.PriorityQueue;
    035import java.util.Queue;
    036import java.util.Stack;
    037
    038/**
    039 * The DumpArchiveInputStream reads a UNIX dump archive as an InputStream.
    040 * Methods are provided to position at each successive entry in
    041 * the archive, and the read each entry as a normal input stream
    042 * using read().
    043 *
    044 * There doesn't seem to exist a hint on the encoding of string values
    045 * in any piece documentation.  Given the main purpose of dump/restore
    046 * is backing up a system it seems very likely the format uses the
    047 * current default encoding of the system.
    048 *
    049 * @NotThreadSafe
    050 */
    051public class DumpArchiveInputStream extends ArchiveInputStream {
    052    private DumpArchiveSummary summary;
    053    private DumpArchiveEntry active;
    054    private boolean isClosed;
    055    private boolean hasHitEOF;
    056    private long entrySize;
    057    private long entryOffset;
    058    private int readIdx;
    059    private final byte[] readBuf = new byte[DumpArchiveConstants.TP_SIZE];
    060    private byte[] blockBuffer;
    061    private int recordOffset;
    062    private long filepos;
    063    protected TapeInputStream raw;
    064
    065    // map of ino -> dirent entry. We can use this to reconstruct full paths.
    066    private final Map<Integer, Dirent> names = new HashMap<>();
    067
    068    // map of ino -> (directory) entry when we're missing one or more elements in the path.
    069    private final Map<Integer, DumpArchiveEntry> pending = new HashMap<>();
    070
    071    // queue of (directory) entries where we now have the full path.
    072    private Queue<DumpArchiveEntry> queue;
    073
    074    /**
    075     * The encoding to use for filenames and labels.
    076     */
    077    private final ZipEncoding zipEncoding;
    078
    079    // the provided encoding (for unit tests)
    080    final String encoding;
    081
    082    /**
    083     * Constructor using the platform's default encoding for file
    084     * names.
    085     *
    086     * @param is stream to read from
    087     * @throws ArchiveException on error
    088     */
    089    public DumpArchiveInputStream(final InputStream is) throws ArchiveException {
    090        this(is, null);
    091    }
    092
    093    /**
    094     * Constructor.
    095     *
    096     * @param is stream to read from
    097     * @param encoding the encoding to use for file names, use null
    098     * for the platform's default encoding
    099     * @since 1.6
    100     * @throws ArchiveException on error
    101     */
    102    public DumpArchiveInputStream(final InputStream is, final String encoding)
    103        throws ArchiveException {
    104        this.raw = new TapeInputStream(is);
    105        this.hasHitEOF = false;
    106        this.encoding = encoding;
    107        this.zipEncoding = ZipEncodingHelper.getZipEncoding(encoding);
    108
    109        try {
    110            // read header, verify it's a dump archive.
    111            final byte[] headerBytes = raw.readRecord();
    112
    113            if (!DumpArchiveUtil.verify(headerBytes)) {
    114                throw new UnrecognizedFormatException();
    115            }
    116
    117            // get summary information
    118            summary = new DumpArchiveSummary(headerBytes, this.zipEncoding);
    119
    120            // reset buffer with actual block size.
    121            raw.resetBlockSize(summary.getNTRec(), summary.isCompressed());
    122
    123            // allocate our read buffer.
    124            blockBuffer = new byte[4 * DumpArchiveConstants.TP_SIZE];
    125
    126            // skip past CLRI and BITS segments since we don't handle them yet.
    127            readCLRI();
    128            readBITS();
    129        } catch (final IOException ex) {
    130            throw new ArchiveException(ex.getMessage(), ex);
    131        }
    132
    133        // put in a dummy record for the root node.
    134        final Dirent root = new Dirent(2, 2, 4, ".");
    135        names.put(2, root);
    136
    137        // use priority based on queue to ensure parent directories are
    138        // released first.
    139        queue = new PriorityQueue<>(10,
    140                new Comparator<DumpArchiveEntry>() {
    141                    @Override
    142                    public int compare(final DumpArchiveEntry p, final DumpArchiveEntry q) {
    143                        if (p.getOriginalName() == null || q.getOriginalName() == null) {
    144                            return Integer.MAX_VALUE;
    145                        }
    146
    147                        return p.getOriginalName().compareTo(q.getOriginalName());
    148                    }
    149                });
    150    }
    151
    152    @Deprecated
    153    @Override
    154    public int getCount() {
    155        return (int) getBytesRead();
    156    }
    157
    158    @Override
    159    public long getBytesRead() {
    160        return raw.getBytesRead();
    161    }
    162
    163    /**
    164     * Return the archive summary information.
    165     * @return the summary
    166     */
    167    public DumpArchiveSummary getSummary() {
    168        return summary;
    169    }
    170
    171    /**
    172     * Read CLRI (deleted inode) segment.
    173     */
    174    private void readCLRI() throws IOException {
    175        final byte[] buffer = raw.readRecord();
    176
    177        if (!DumpArchiveUtil.verify(buffer)) {
    178            throw new InvalidFormatException();
    179        }
    180
    181        active = DumpArchiveEntry.parse(buffer);
    182
    183        if (DumpArchiveConstants.SEGMENT_TYPE.CLRI != active.getHeaderType()) {
    184            throw new InvalidFormatException();
    185        }
    186
    187        // we don't do anything with this yet.
    188        if (raw.skip((long) DumpArchiveConstants.TP_SIZE * active.getHeaderCount())
    189            == -1) {
    190            throw new EOFException();
    191        }
    192        readIdx = active.getHeaderCount();
    193    }
    194
    195    /**
    196     * Read BITS segment.
    197     */
    198    private void readBITS() throws IOException {
    199        final byte[] buffer = raw.readRecord();
    200
    201        if (!DumpArchiveUtil.verify(buffer)) {
    202            throw new InvalidFormatException();
    203        }
    204
    205        active = DumpArchiveEntry.parse(buffer);
    206
    207        if (DumpArchiveConstants.SEGMENT_TYPE.BITS != active.getHeaderType()) {
    208            throw new InvalidFormatException();
    209        }
    210
    211        // we don't do anything with this yet.
    212        if (raw.skip((long) DumpArchiveConstants.TP_SIZE * active.getHeaderCount())
    213            == -1) {
    214            throw new EOFException();
    215        }
    216        readIdx = active.getHeaderCount();
    217    }
    218
    219    /**
    220     * Read the next entry.
    221     * @return the next entry
    222     * @throws IOException on error
    223     */
    224    public DumpArchiveEntry getNextDumpEntry() throws IOException {
    225        return getNextEntry();
    226    }
    227
    228    @Override
    229    public DumpArchiveEntry getNextEntry() throws IOException {
    230        DumpArchiveEntry entry = null;
    231        String path = null;
    232
    233        // is there anything in the queue?
    234        if (!queue.isEmpty()) {
    235            return queue.remove();
    236        }
    237
    238        while (entry == null) {
    239            if (hasHitEOF) {
    240                return null;
    241            }
    242
    243            // skip any remaining records in this segment for prior file.
    244            // we might still have holes... easiest to do it
    245            // block by block. We may want to revisit this if
    246            // the unnecessary decompression time adds up.
    247            while (readIdx < active.getHeaderCount()) {
    248                if (!active.isSparseRecord(readIdx++)
    249                    && raw.skip(DumpArchiveConstants.TP_SIZE) == -1) {
    250                    throw new EOFException();
    251                }
    252            }
    253
    254            readIdx = 0;
    255            filepos = raw.getBytesRead();
    256
    257            byte[] headerBytes = raw.readRecord();
    258
    259            if (!DumpArchiveUtil.verify(headerBytes)) {
    260                throw new InvalidFormatException();
    261            }
    262
    263            active = DumpArchiveEntry.parse(headerBytes);
    264
    265            // skip any remaining segments for prior file.
    266            while (DumpArchiveConstants.SEGMENT_TYPE.ADDR == active.getHeaderType()) {
    267                if (raw.skip((long) DumpArchiveConstants.TP_SIZE
    268                             * (active.getHeaderCount()
    269                                - active.getHeaderHoles())) == -1) {
    270                    throw new EOFException();
    271                }
    272
    273                filepos = raw.getBytesRead();
    274                headerBytes = raw.readRecord();
    275
    276                if (!DumpArchiveUtil.verify(headerBytes)) {
    277                    throw new InvalidFormatException();
    278                }
    279
    280                active = DumpArchiveEntry.parse(headerBytes);
    281            }
    282
    283            // check if this is an end-of-volume marker.
    284            if (DumpArchiveConstants.SEGMENT_TYPE.END == active.getHeaderType()) {
    285                hasHitEOF = true;
    286
    287                return null;
    288            }
    289
    290            entry = active;
    291
    292            if (entry.isDirectory()) {
    293                readDirectoryEntry(active);
    294
    295                // now we create an empty InputStream.
    296                entryOffset = 0;
    297                entrySize = 0;
    298                readIdx = active.getHeaderCount();
    299            } else {
    300                entryOffset = 0;
    301                entrySize = active.getEntrySize();
    302                readIdx = 0;
    303            }
    304
    305            recordOffset = readBuf.length;
    306
    307            path = getPath(entry);
    308
    309            if (path == null) {
    310                entry = null;
    311            }
    312        }
    313
    314        entry.setName(path);
    315        entry.setSimpleName(names.get(entry.getIno()).getName());
    316        entry.setOffset(filepos);
    317
    318        return entry;
    319    }
    320
    321    /**
    322     * Read directory entry.
    323     */
    324    private void readDirectoryEntry(DumpArchiveEntry entry)
    325        throws IOException {
    326        long size = entry.getEntrySize();
    327        boolean first = true;
    328
    329        while (first ||
    330                DumpArchiveConstants.SEGMENT_TYPE.ADDR == entry.getHeaderType()) {
    331            // read the header that we just peeked at.
    332            if (!first) {
    333                raw.readRecord();
    334            }
    335
    336            if (!names.containsKey(entry.getIno()) &&
    337                    DumpArchiveConstants.SEGMENT_TYPE.INODE == entry.getHeaderType()) {
    338                pending.put(entry.getIno(), entry);
    339            }
    340
    341            final int datalen = DumpArchiveConstants.TP_SIZE * entry.getHeaderCount();
    342
    343            if (blockBuffer.length < datalen) {
    344                blockBuffer = new byte[datalen];
    345            }
    346
    347            if (raw.read(blockBuffer, 0, datalen) != datalen) {
    348                throw new EOFException();
    349            }
    350
    351            int reclen = 0;
    352
    353            for (int i = 0; i < datalen - 8 && i < size - 8;
    354                    i += reclen) {
    355                final int ino = DumpArchiveUtil.convert32(blockBuffer, i);
    356                reclen = DumpArchiveUtil.convert16(blockBuffer, i + 4);
    357
    358                final byte type = blockBuffer[i + 6];
    359
    360                final String name = DumpArchiveUtil.decode(zipEncoding, blockBuffer, i + 8, blockBuffer[i + 7]);
    361
    362                if (".".equals(name) || "..".equals(name)) {
    363                    // do nothing...
    364                    continue;
    365                }
    366
    367                final Dirent d = new Dirent(ino, entry.getIno(), type, name);
    368
    369                /*
    370                if ((type == 4) && names.containsKey(ino)) {
    371                    System.out.println("we already have ino: " +
    372                                       names.get(ino));
    373                }
    374                */
    375
    376                names.put(ino, d);
    377
    378                // check whether this allows us to fill anything in the pending list.
    379                for (final Map.Entry<Integer, DumpArchiveEntry> e : pending.entrySet()) {
    380                    final String path = getPath(e.getValue());
    381
    382                    if (path != null) {
    383                        e.getValue().setName(path);
    384                        e.getValue()
    385                         .setSimpleName(names.get(e.getKey()).getName());
    386                        queue.add(e.getValue());
    387                    }
    388                }
    389
    390                // remove anything that we found. (We can't do it earlier
    391                // because of concurrent modification exceptions.)
    392                for (final DumpArchiveEntry e : queue) {
    393                    pending.remove(e.getIno());
    394                }
    395            }
    396
    397            final byte[] peekBytes = raw.peek();
    398
    399            if (!DumpArchiveUtil.verify(peekBytes)) {
    400                throw new InvalidFormatException();
    401            }
    402
    403            entry = DumpArchiveEntry.parse(peekBytes);
    404            first = false;
    405            size -= DumpArchiveConstants.TP_SIZE;
    406        }
    407    }
    408
    409    /**
    410     * Get full path for specified archive entry, or null if there's a gap.
    411     *
    412     * @param entry
    413     * @return  full path for specified archive entry, or null if there's a gap.
    414     */
    415    private String getPath(final DumpArchiveEntry entry) {
    416        // build the stack of elements. It's possible that we're
    417        // still missing an intermediate value and if so we
    418        final Stack<String> elements = new Stack<>();
    419        Dirent dirent = null;
    420
    421        for (int i = entry.getIno();; i = dirent.getParentIno()) {
    422            if (!names.containsKey(i)) {
    423                elements.clear();
    424                break;
    425            }
    426
    427            dirent = names.get(i);
    428            elements.push(dirent.getName());
    429
    430            if (dirent.getIno() == dirent.getParentIno()) {
    431                break;
    432            }
    433        }
    434
    435        // if an element is missing defer the work and read next entry.
    436        if (elements.isEmpty()) {
    437            pending.put(entry.getIno(), entry);
    438
    439            return null;
    440        }
    441
    442        // generate full path from stack of elements.
    443        final StringBuilder sb = new StringBuilder(elements.pop());
    444
    445        while (!elements.isEmpty()) {
    446            sb.append('/');
    447            sb.append(elements.pop());
    448        }
    449
    450        return sb.toString();
    451    }
    452
    453    /**
    454     * Reads bytes from the current dump archive entry.
    455     *
    456     * This method is aware of the boundaries of the current
    457     * entry in the archive and will deal with them as if they
    458     * were this stream's start and EOF.
    459     *
    460     * @param buf The buffer into which to place bytes read.
    461     * @param off The offset at which to place bytes read.
    462     * @param len The number of bytes to read.
    463     * @return The number of bytes read, or -1 at EOF.
    464     * @throws IOException on error
    465     */
    466    @Override
    467    public int read(final byte[] buf, int off, int len) throws IOException {
    468        int totalRead = 0;
    469
    470        if (hasHitEOF || isClosed || entryOffset >= entrySize) {
    471            return -1;
    472        }
    473
    474        if (active == null) {
    475            throw new IllegalStateException("No current dump entry");
    476        }
    477
    478        if (len + entryOffset > entrySize) {
    479            len = (int) (entrySize - entryOffset);
    480        }
    481
    482        while (len > 0) {
    483            final int sz = len > readBuf.length - recordOffset
    484                ? readBuf.length - recordOffset : len;
    485
    486            // copy any data we have
    487            if (recordOffset + sz <= readBuf.length) {
    488                System.arraycopy(readBuf, recordOffset, buf, off, sz);
    489                totalRead += sz;
    490                recordOffset += sz;
    491                len -= sz;
    492                off += sz;
    493            }
    494
    495            // load next block if necessary.
    496            if (len > 0) {
    497                if (readIdx >= 512) {
    498                    final byte[] headerBytes = raw.readRecord();
    499
    500                    if (!DumpArchiveUtil.verify(headerBytes)) {
    501                        throw new InvalidFormatException();
    502                    }
    503
    504                    active = DumpArchiveEntry.parse(headerBytes);
    505                    readIdx = 0;
    506                }
    507
    508                if (!active.isSparseRecord(readIdx++)) {
    509                    final int r = raw.read(readBuf, 0, readBuf.length);
    510                    if (r != readBuf.length) {
    511                        throw new EOFException();
    512                    }
    513                } else {
    514                    Arrays.fill(readBuf, (byte) 0);
    515                }
    516
    517                recordOffset = 0;
    518            }
    519        }
    520
    521        entryOffset += totalRead;
    522
    523        return totalRead;
    524    }
    525
    526    /**
    527     * Closes the stream for this entry.
    528     */
    529    @Override
    530    public void close() throws IOException {
    531        if (!isClosed) {
    532            isClosed = true;
    533            raw.close();
    534        }
    535    }
    536
    537    /**
    538     * Look at the first few bytes of the file to decide if it's a dump
    539     * archive. With 32 bytes we can look at the magic value, with a full
    540     * 1k we can verify the checksum.
    541     * @param buffer data to match
    542     * @param length length of data
    543     * @return whether the buffer seems to contain dump data
    544     */
    545    public static boolean matches(final byte[] buffer, final int length) {
    546        // do we have enough of the header?
    547        if (length < 32) {
    548            return false;
    549        }
    550
    551        // this is the best test
    552        if (length >= DumpArchiveConstants.TP_SIZE) {
    553            return DumpArchiveUtil.verify(buffer);
    554        }
    555
    556        // this will work in a pinch.
    557        return DumpArchiveConstants.NFS_MAGIC == DumpArchiveUtil.convert32(buffer,
    558            24);
    559    }
    560
    561}