1 files changed, 593 insertions, 0 deletions
diff --git a/mozglue/linker/szip.cpp b/mozglue/linker/szip.cpp
new file mode 100644
index 000000000..bfc882fbe
--- /dev/null
+++ b/mozglue/linker/szip.cpp
@@ -0,0 +1,593 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+#include <map>
+#include <sys/stat.h>
+#include <string>
+#include <sstream>
+#include <cstring>
+#include <cstdlib>
+#include <zlib.h>
+#include <fcntl.h>
+#include <errno.h>
+#include "mozilla/Assertions.h"
+#include "mozilla/Scoped.h"
+#include "mozilla/UniquePtr.h"
+#include "SeekableZStream.h"
+#include "Utils.h"
+#include "Logging.h"
+
+Logging Logging::Singleton;
+
+const char *filterName[] = {
+  "none",
+  "thumb",
+  "arm",
+  "x86",
+  "auto"
+};
+
+/* Maximum supported size for chunkSize */
+static const size_t maxChunkSize =
+  1 << (8 * std::min(sizeof(((SeekableZStreamHeader *)nullptr)->chunkSize),
+                     sizeof(((SeekableZStreamHeader *)nullptr)->lastChunkSize)) - 1);
+
+class Buffer: public MappedPtr
+{
+public:
+  virtual ~Buffer() { }
+
+  virtual bool Resize(size_t size)
+  {
+    MemoryRange buf = mmap(nullptr, size, PROT_READ | PROT_WRITE,
+                           MAP_PRIVATE | MAP_ANON, -1, 0);
+    if (buf == MAP_FAILED)
+      return false;
+    if (*this != MAP_FAILED)
+      memcpy(buf, *this, std::min(size, GetLength()));
+    Assign(buf);
+    return true;
+  }
+
+  bool Fill(Buffer &other)
+  {
+    size_t size = other.GetLength();
+    if (!size || !Resize(size))
+      return false;
+    memcpy(static_cast<void *>(*this), static_cast<void *>(other), size);
+    return true;
+  }
+};
+
+class FileBuffer: public Buffer
+{
+public:
+  bool Init(const char *name, bool writable_ = false)
+  {
+    fd = open(name, writable_ ? O_RDWR | O_CREAT | O_TRUNC : O_RDONLY, 0666);
+    if (fd == -1)
+      return false;
+    writable = writable_;
+    return true;
+  }
+
+  virtual bool Resize(size_t size)
+  {
+    if (writable) {
+      if (ftruncate(fd, size) == -1)
+        return false;
+    }
+    Assign(MemoryRange::mmap(nullptr, size,
+                             PROT_READ | (writable ? PROT_WRITE : 0),
+                             writable ? MAP_SHARED : MAP_PRIVATE, fd, 0));
+    return this != MAP_FAILED;
+  }
+
+  int getFd()
+  {
+    return fd;
+  }
+
+private:
+  AutoCloseFD fd;
+  bool writable;
+};
+
+class FilteredBuffer: public Buffer
+{
+public:
+  void Filter(Buffer &other, SeekableZStream::FilterId filter, size_t chunkSize)
+  {
+    SeekableZStream::ZStreamFilter filterCB =
+      SeekableZStream::GetFilter(filter);
+    MOZ_ASSERT(filterCB);
+    Fill(other);
+    size_t size = other.GetLength();
+    Bytef *data = reinterpret_cast<Bytef *>(static_cast<void *>(*this));
+    size_t avail = 0;
+    /* Filter needs to be applied in chunks. */
+    while (size) {
+      avail = std::min(size, chunkSize);
+      filterCB(data - static_cast<unsigned char *>(static_cast<void *>(*this)),
+               SeekableZStream::FILTER, data, avail);
+      size -= avail;
+      data += avail;
+    }
+  }
+};
+
+template <typename T>
+class Dictionary: public Buffer
+{
+  typedef T piece;
+  typedef std::pair<piece, int> stat_pair;
+
+  static bool stat_cmp(stat_pair a, stat_pair b)
+  {
+    return a.second < b.second;
+  }
+
+public:
+  Dictionary(Buffer &inBuf, size_t size)
+  {
+    if (!size || !Resize(size))
+      return;
+    DEBUG_LOG("Creating dictionary");
+    piece *origBufPieces = reinterpret_cast<piece *>(
+                           static_cast<void *>(inBuf));
+    std::map<piece, int> stats;
+    for (unsigned int i = 0; i < inBuf.GetLength() / sizeof(piece); i++) {
+      stats[origBufPieces[i]]++;
+    }
+    std::vector<stat_pair> statsVec(stats.begin(), stats.end());
+    std::sort(statsVec.begin(), statsVec.end(), stat_cmp);
+
+    piece *dictPieces = reinterpret_cast<piece *>(
+                        static_cast<void *>(*this));
+    typename std::vector<stat_pair>::reverse_iterator it = statsVec.rbegin();
+    for (int i = size / sizeof(piece); i > 0 && it < statsVec.rend();
+         i--, ++it) {
+      dictPieces[i - 1] = it->first;
+    }
+  }
+};
+
+class SzipAction
+{
+public:
+  virtual int run(const char *name, Buffer &origBuf,
+                  const char *outName, Buffer &outBuf) = 0;
+
+  virtual ~SzipAction() {}
+};
+
+class SzipDecompress: public SzipAction
+{
+public:
+  int run(const char *name, Buffer &origBuf,
+          const char *outName, Buffer &outBuf);
+};
+
+
+class SzipCompress: public SzipAction
+{
+public:
+  int run(const char *name, Buffer &origBuf,
+          const char *outName, Buffer &outBuf);
+
+  SzipCompress(size_t aChunkSize, SeekableZStream::FilterId aFilter,
+               size_t aDictSize)
+  : chunkSize(aChunkSize ? aChunkSize : 16384)
+  , filter(aFilter)
+  , dictSize(aDictSize)
+  {}
+
+  const static signed char winSizeLog = 15;
+  const static size_t winSize = 1 << winSizeLog;
+
+  const static SeekableZStream::FilterId DEFAULT_FILTER =
+#if defined(TARGET_THUMB)
+    SeekableZStream::BCJ_THUMB;
+#elif defined(TARGET_ARM)
+    SeekableZStream::BCJ_ARM;
+#elif defined(TARGET_X86)
+    SeekableZStream::BCJ_X86;
+#else
+    SeekableZStream::NONE;
+#endif
+
+private:
+
+  int do_compress(Buffer &origBuf, Buffer &outBuf, const unsigned char *aDict,
+                  size_t aDictSize, SeekableZStream::FilterId aFilter);
+
+  size_t chunkSize;
+  SeekableZStream::FilterId filter;
+  size_t dictSize;
+};
+
+/* Decompress a seekable compressed stream */
+int SzipDecompress::run(const char *name, Buffer &origBuf,
+                        const char *outName, Buffer &outBuf)
+{
+  size_t origSize = origBuf.GetLength();
+  if (origSize < sizeof(SeekableZStreamHeader)) {
+    ERROR("%s is not compressed", name);
+    return 0;
+  }
+
+  SeekableZStream zstream;
+  if (!zstream.Init(origBuf, origSize))
+    return 0;
+
+  size_t size = zstream.GetUncompressedSize();
+
+  /* Give enough room for the uncompressed data */
+  if (!outBuf.Resize(size)) {
+    ERROR("Error resizing %s: %s", outName, strerror(errno));
+    return 1;
+  }
+
+  if (!zstream.Decompress(outBuf, 0, size))
+    return 1;
+
+  return 0;
+}
+
+/* Generate a seekable compressed stream. */
+int SzipCompress::run(const char *name, Buffer &origBuf,
+                      const char *outName, Buffer &outBuf)
+{
+  size_t origSize = origBuf.GetLength();
+  if (origSize == 0) {
+    ERROR("Won't compress %s: it's empty", name);
+    return 1;
+  }
+  if (SeekableZStreamHeader::validate(origBuf)) {
+    WARN("Skipping %s: it's already a szip", name);
+    return 0;
+  }
+  bool compressed = false;
+  LOG("Size = %" PRIuSize, origSize);
+
+  /* Allocate a buffer the size of the uncompressed data: we don't want
+   * a compressed file larger than that anyways. */
+  if (!outBuf.Resize(origSize)) {
+    ERROR("Couldn't allocate output buffer: %s", strerror(errno));
+    return 1;
+  }
+
+  /* Find the most appropriate filter */
+  SeekableZStream::FilterId firstFilter, lastFilter;
+  bool scanFilters;
+  if (filter == SeekableZStream::FILTER_MAX) {
+    firstFilter = SeekableZStream::NONE;
+    lastFilter = SeekableZStream::FILTER_MAX;
+    scanFilters = true;
+  } else {
+    firstFilter = lastFilter = filter;
+    ++lastFilter;
+    scanFilters = false;
+  }
+
+  mozilla::UniquePtr<Buffer> filteredBuf;
+  Buffer *origData;
+  for (SeekableZStream::FilterId f = firstFilter; f < lastFilter; ++f) {
+    mozilla::UniquePtr<FilteredBuffer> filteredTmp;
+    Buffer tmpBuf;
+    if (f != SeekableZStream::NONE) {
+      DEBUG_LOG("Applying filter \"%s\"", filterName[f]);
+      filteredTmp = mozilla::MakeUnique<FilteredBuffer>();
+      filteredTmp->Filter(origBuf, f, chunkSize);
+      origData = filteredTmp.get();
+    } else {
+      origData = &origBuf;
+    }
+    if (dictSize  && !scanFilters) {
+      filteredBuf = mozilla::Move(filteredTmp);
+      break;
+    }
+    DEBUG_LOG("Compressing with no dictionary");
+    if (do_compress(*origData, tmpBuf, nullptr, 0, f) == 0) {
+      if (tmpBuf.GetLength() < outBuf.GetLength()) {
+        outBuf.Fill(tmpBuf);
+        compressed = true;
+        filter = f;
+        filteredBuf = mozilla::Move(filteredTmp);
+        continue;
+      }
+    }
+  }
+
+  origData = filteredBuf ? filteredBuf.get() : &origBuf;
+
+  if (dictSize) {
+    Dictionary<uint64_t> dict(*origData, dictSize ? SzipCompress::winSize : 0);
+
+    /* Find the most appropriate dictionary size */
+    size_t firstDictSize, lastDictSize;
+    if (dictSize == (size_t) -1) {
+      /* If we scanned for filters, we effectively already tried dictSize=0 */
+      firstDictSize = scanFilters ? 4096 : 0;
+      lastDictSize = SzipCompress::winSize;
+    } else {
+      firstDictSize = lastDictSize = dictSize;
+    }
+
+    Buffer tmpBuf;
+    for (size_t d = firstDictSize; d <= lastDictSize; d += 4096) {
+      DEBUG_LOG("Compressing with dictionary of size %" PRIuSize, d);
+      if (do_compress(*origData, tmpBuf, static_cast<unsigned char *>(dict)
+                      + SzipCompress::winSize - d, d, filter))
+        continue;
+      if (!compressed || tmpBuf.GetLength() < outBuf.GetLength()) {
+        outBuf.Fill(tmpBuf);
+        compressed = true;
+        dictSize = d;
+      }
+    }
+  }
+
+  if (!compressed) {
+    outBuf.Fill(origBuf);
+    LOG("Not compressed");
+    return 0;
+  }
+
+  if (dictSize == (size_t) -1)
+    dictSize = 0;
+
+  DEBUG_LOG("Used filter \"%s\" and dictionary size of %" PRIuSize,
+            filterName[filter], dictSize);
+  LOG("Compressed size is %" PRIuSize, outBuf.GetLength());
+
+  /* Sanity check */
+  Buffer tmpBuf;
+  SzipDecompress decompress;
+  if (decompress.run("buffer", outBuf, "buffer", tmpBuf))
+    return 1;
+
+  size_t size = tmpBuf.GetLength();
+  if (size != origSize) {
+    ERROR("Compression error: %" PRIuSize " != %" PRIuSize, size, origSize);
+    return 1;
+  }
+  if (memcmp(static_cast<void *>(origBuf), static_cast<void *>(tmpBuf), size)) {
+    ERROR("Compression error: content mismatch");
+    return 1;
+  }
+  return 0;
+}
+
+int SzipCompress::do_compress(Buffer &origBuf, Buffer &outBuf,
+                              const unsigned char *aDict, size_t aDictSize,
+                              SeekableZStream::FilterId aFilter)
+{
+  size_t origSize = origBuf.GetLength();
+  MOZ_ASSERT(origSize != 0);
+
+  /* Expected total number of chunks */
+  size_t nChunks = ((origSize + chunkSize - 1) / chunkSize);
+
+  /* The first chunk is going to be stored after the header, the dictionary
+   * and the offset table */
+  size_t offset = sizeof(SeekableZStreamHeader) + aDictSize
+                  + nChunks * sizeof(uint32_t);
+
+  if (offset >= origSize)
+    return 1;
+
+    /* Allocate a buffer the size of the uncompressed data: we don't want
+   * a compressed file larger than that anyways. */
+  if (!outBuf.Resize(origSize)) {
+    ERROR("Couldn't allocate output buffer: %s", strerror(errno));
+    return 1;
+  }
+
+  SeekableZStreamHeader *header = new (outBuf) SeekableZStreamHeader;
+  unsigned char *dictionary = static_cast<unsigned char *>(
+                              outBuf + sizeof(SeekableZStreamHeader));
+  le_uint32 *entry =
+    reinterpret_cast<le_uint32 *>(dictionary + aDictSize);
+
+  /* Initialize header */
+  header->chunkSize = chunkSize;
+  header->dictSize = aDictSize;
+  header->totalSize = offset;
+  header->windowBits = -SzipCompress::winSizeLog; // Raw stream,
+                                                  // window size of 32k.
+  header->filter = aFilter;
+  if (aDictSize)
+    memcpy(dictionary, aDict, aDictSize);
+
+  /* Initialize zlib structure */
+  z_stream zStream;
+  memset(&zStream, 0, sizeof(zStream));
+  zStream.avail_out = origSize - offset;
+  zStream.next_out = static_cast<Bytef*>(outBuf) + offset;
+
+  size_t avail = 0;
+  size_t size = origSize;
+  unsigned char *data = reinterpret_cast<unsigned char *>(
+                        static_cast<void *>(origBuf));
+  while (size) {
+    avail = std::min(size, chunkSize);
+
+    /* Compress chunk */
+    int ret = deflateInit2(&zStream, 9, Z_DEFLATED, header->windowBits,
+                           MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+    if (aDictSize)
+      deflateSetDictionary(&zStream, dictionary, aDictSize);
+    MOZ_ASSERT(ret == Z_OK);
+    zStream.avail_in = avail;
+    zStream.next_in = data;
+    ret = deflate(&zStream, Z_FINISH);
+    /* Under normal conditions, deflate returns Z_STREAM_END. If there is not
+     * enough room to compress, deflate returns Z_OK and avail_out is 0. We
+     * still want to deflateEnd in that case, so fall through. It will bail
+     * on the avail_out test that follows. */
+    MOZ_ASSERT(ret == Z_STREAM_END || ret == Z_OK);
+    ret = deflateEnd(&zStream);
+    MOZ_ASSERT(ret == Z_OK);
+    if (zStream.avail_out <= 0)
+      return 1;
+
+    size_t len = origSize - offset - zStream.avail_out;
+
+    /* Adjust headers */
+    header->totalSize += len;
+    *entry++ = offset;
+    header->nChunks++;
+
+    /* Prepare for next iteration */
+    size -= avail;
+    data += avail;
+    offset += len;
+  }
+  header->lastChunkSize = avail;
+  MOZ_ASSERT(header->totalSize == offset);
+  MOZ_ASSERT(header->nChunks == nChunks);
+
+  if (!outBuf.Resize(offset)) {
+    ERROR("Error truncating output: %s", strerror(errno));
+    return 1;
+  }
+
+  return 0;
+
+}
+
+bool GetSize(const char *str, size_t *out)
+{
+  char *end;
+  MOZ_ASSERT(out);
+  errno = 0;
+  *out = strtol(str, &end, 10);
+  return (!errno && !*end);
+}
+
+int main(int argc, char* argv[])
+{
+  mozilla::UniquePtr<SzipAction> action;
+  char **firstArg;
+  bool compress = true;
+  size_t chunkSize = 0;
+  SeekableZStream::FilterId filter = SzipCompress::DEFAULT_FILTER;
+  size_t dictSize = (size_t) 0;
+
+  Logging::Init();
+
+  for (firstArg = &argv[1]; argc > 2; argc--, firstArg++) {
+    if (!firstArg[0] || firstArg[0][0] != '-')
+      break;
+    if (strcmp(firstArg[0], "-d") == 0) {
+      compress = false;
+    } else if (strcmp(firstArg[0], "-c") == 0) {
+      firstArg++;
+      argc--;
+      if (!firstArg[0])
+        break;
+      if (!GetSize(firstArg[0], &chunkSize) || !chunkSize ||
+          (chunkSize % 4096) || (chunkSize > maxChunkSize)) {
+        ERROR("Invalid chunk size");
+        return 1;
+      }
+    } else if (strcmp(firstArg[0], "-f") == 0) {
+      firstArg++;
+      argc--;
+      if (!firstArg[0])
+        break;
+      bool matched = false;
+      for (unsigned int i = 0; i < sizeof(filterName) / sizeof(char *); ++i) {
+        if (strcmp(firstArg[0], filterName[i]) == 0) {
+          filter = static_cast<SeekableZStream::FilterId>(i);
+          matched = true;
+          break;
+        }
+      }
+      if (!matched) {
+        ERROR("Invalid filter");
+        return 1;
+      }
+    } else if (strcmp(firstArg[0], "-D") == 0) {
+      firstArg++;
+      argc--;
+      if (!firstArg[0])
+        break;
+      if (strcmp(firstArg[0], "auto") == 0) {
+        dictSize = -1;
+      } else if (!GetSize(firstArg[0], &dictSize) || (dictSize >= 1 << 16)) {
+        ERROR("Invalid dictionary size");
+        return 1;
+      }
+    }
+  }
+
+  if (argc != 2 || !firstArg[0]) {
+    LOG("usage: %s [-d] [-c CHUNKSIZE] [-f FILTER] [-D DICTSIZE] file",
+        argv[0]);
+    return 1;
+  }
+
+  if (compress) {
+    action.reset(new SzipCompress(chunkSize, filter, dictSize));
+  } else {
+    if (chunkSize) {
+      ERROR("-c is incompatible with -d");
+      return 1;
+    }
+    if (dictSize) {
+      ERROR("-D is incompatible with -d");
+      return 1;
+    }
+    action.reset(new SzipDecompress());
+  }
+
+  std::stringstream tmpOutStream;
+  tmpOutStream << firstArg[0] << ".sz." << getpid();
+  std::string tmpOut(tmpOutStream.str());
+  int ret;
+  struct stat st;
+  {
+    FileBuffer origBuf;
+    if (!origBuf.Init(firstArg[0])) {
+      ERROR("Couldn't open %s: %s", firstArg[0], strerror(errno));
+      return 1;
+    }
+
+    ret = fstat(origBuf.getFd(), &st);
+    if (ret == -1) {
+      ERROR("Couldn't stat %s: %s", firstArg[0], strerror(errno));
+      return 1;
+    }
+
+    size_t origSize = st.st_size;
+
+    /* Mmap the original file */
+    if (!origBuf.Resize(origSize)) {
+      ERROR("Couldn't mmap %s: %s", firstArg[0], strerror(errno));
+      return 1;
+    }
+
+    /* Create the compressed file */
+    FileBuffer outBuf;
+    if (!outBuf.Init(tmpOut.c_str(), true)) {
+      ERROR("Couldn't open %s: %s", tmpOut.c_str(), strerror(errno));
+      return 1;
+    }
+
+    ret = action->run(firstArg[0], origBuf, tmpOut.c_str(), outBuf);
+    if ((ret == 0) && (fstat(outBuf.getFd(), &st) == -1)) {
+      st.st_size = 0;
+    }
+  }
+
+  if ((ret == 0) && st.st_size) {
+    rename(tmpOut.c_str(), firstArg[0]);
+  } else {
+    unlink(tmpOut.c_str());
+  }
+  return ret;
+}