Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

22 files changed, 7021 insertions, 0 deletions

diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/cpu_set.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/cpu_set.h
new file mode 100644
index 0000000000..1cca9aa5a0
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/cpu_set.h
@@ -0,0 +1,144 @@
+// Copyright (c) 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_
+
+#include <stdint.h>
+#include <assert.h>
+#include <string.h>
+
+#include "common/linux/linux_libc_support.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+namespace google_breakpad {
+
+// Helper class used to model a set of CPUs, as read from sysfs
+// files like /sys/devices/system/cpu/present
+// See See http://www.kernel.org/doc/Documentation/cputopology.txt
+class CpuSet {
+public:
+  // The maximum number of supported CPUs.
+  static const size_t kMaxCpus = 1024;
+
+  CpuSet() {
+    my_memset(mask_, 0, sizeof(mask_));
+  }
+
+  // Parse a sysfs file to extract the corresponding CPU set.
+  bool ParseSysFile(int fd) {
+    char buffer[512];
+    int ret = sys_read(fd, buffer, sizeof(buffer)-1);
+    if (ret < 0)
+      return false;
+
+    buffer[ret] = '\0';
+
+    // Expected format: comma-separated list of items, where each
+    // item can be a decimal integer, or two decimal integers separated
+    // by a dash.
+    // E.g.:
+    //       0
+    //       0,1,2,3
+    //       0-3
+    //       1,10-23
+    const char* p = buffer;
+    const char* p_end = p + ret;
+    while (p < p_end) {
+      // Skip leading space, if any
+      while (p < p_end && my_isspace(*p))
+        p++;
+
+      // Find start and size of current item.
+      const char* item = p;
+      size_t item_len = static_cast<size_t>(p_end - p);
+      const char* item_next =
+          static_cast<const char*>(my_memchr(p, ',', item_len));
+      if (item_next != NULL) {
+        p = item_next + 1;
+        item_len = static_cast<size_t>(item_next - item);
+      } else {
+        p = p_end;
+        item_next = p_end;
+      }
+
+      // Ignore trailing spaces.
+      while (item_next > item && my_isspace(item_next[-1]))
+        item_next--;
+
+      // skip empty items.
+      if (item_next == item)
+        continue;
+
+      // read first decimal value.
+      uintptr_t start = 0;
+      const char* next = my_read_decimal_ptr(&start, item);
+      uintptr_t end = start;
+      if (*next == '-')
+        my_read_decimal_ptr(&end, next+1);
+
+      while (start <= end)
+        SetBit(start++);
+    }
+    return true;
+  }
+
+  // Intersect this CPU set with another one.
+  void IntersectWith(const CpuSet& other) {
+    for (size_t nn = 0; nn < kMaskWordCount; ++nn)
+      mask_[nn] &= other.mask_[nn];
+  }
+
+  // Return the number of CPUs in this set.
+  int GetCount() {
+    int result = 0;
+    for (size_t nn = 0; nn < kMaskWordCount; ++nn) {
+      result += __builtin_popcount(mask_[nn]);
+    }
+    return result;
+  }
+
+private:
+  void SetBit(uintptr_t index) {
+    size_t nn = static_cast<size_t>(index);
+    if (nn < kMaxCpus)
+      mask_[nn / kMaskWordBits] |= (1U << (nn % kMaskWordBits));
+  }
+
+  typedef uint32_t MaskWordType;
+  static const size_t kMaskWordBits = 8*sizeof(MaskWordType);
+  static const size_t kMaskWordCount =
+      (kMaxCpus + kMaskWordBits - 1) / kMaskWordBits;
+
+  MaskWordType mask_[kMaskWordCount];
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/cpu_set_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/cpu_set_unittest.cc
new file mode 100644
index 0000000000..75172e9938
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/cpu_set_unittest.cc
@@ -0,0 +1,164 @@
+// Copyright (c) 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#include "breakpad_googletest_includes.h"
+#include "linux/minidump_writer/cpu_set.h"
+#include "common/linux/tests/auto_testfile.h"
+
+using namespace google_breakpad;
+
+namespace {
+
+typedef testing::Test CpuSetTest;
+
+// Helper class to write test text file to a temporary file and return
+// its file descriptor.
+class ScopedTestFile : public AutoTestFile {
+public:
+  explicit ScopedTestFile(const char* text)
+    : AutoTestFile("cpu_set", text) {
+  }
+};
+
+}
+
+TEST(CpuSetTest, EmptyCount) {
+  CpuSet set;
+  ASSERT_EQ(0, set.GetCount());
+}
+
+TEST(CpuSetTest, OneCpu) {
+  ScopedTestFile file("10");
+  ASSERT_TRUE(file.IsOk());
+
+  CpuSet set;
+  ASSERT_TRUE(set.ParseSysFile(file.GetFd()));
+  ASSERT_EQ(1, set.GetCount());
+}
+
+TEST(CpuSetTest, OneCpuTerminated) {
+  ScopedTestFile file("10\n");
+  ASSERT_TRUE(file.IsOk());
+
+  CpuSet set;
+  ASSERT_TRUE(set.ParseSysFile(file.GetFd()));
+  ASSERT_EQ(1, set.GetCount());
+}
+
+TEST(CpuSetTest, TwoCpusWithComma) {
+  ScopedTestFile file("1,10");
+  ASSERT_TRUE(file.IsOk());
+
+  CpuSet set;
+  ASSERT_TRUE(set.ParseSysFile(file.GetFd()));
+  ASSERT_EQ(2, set.GetCount());
+}
+
+TEST(CpuSetTest, TwoCpusWithRange) {
+  ScopedTestFile file("1-2");
+  ASSERT_TRUE(file.IsOk());
+
+  CpuSet set;
+  ASSERT_TRUE(set.ParseSysFile(file.GetFd()));
+  ASSERT_EQ(2, set.GetCount());
+}
+
+TEST(CpuSetTest, TenCpusWithRange) {
+  ScopedTestFile file("9-18");
+  ASSERT_TRUE(file.IsOk());
+
+  CpuSet set;
+  ASSERT_TRUE(set.ParseSysFile(file.GetFd()));
+  ASSERT_EQ(10, set.GetCount());
+}
+
+TEST(CpuSetTest, MultiItems) {
+  ScopedTestFile file("0, 2-4, 128");
+  ASSERT_TRUE(file.IsOk());
+
+  CpuSet set;
+  ASSERT_TRUE(set.ParseSysFile(file.GetFd()));
+  ASSERT_EQ(5, set.GetCount());
+}
+
+TEST(CpuSetTest, IntersectWith) {
+  ScopedTestFile file1("9-19");
+  ASSERT_TRUE(file1.IsOk());
+  CpuSet set1;
+  ASSERT_TRUE(set1.ParseSysFile(file1.GetFd()));
+  ASSERT_EQ(11, set1.GetCount());
+
+  ScopedTestFile file2("16-24");
+  ASSERT_TRUE(file2.IsOk());
+  CpuSet set2;
+  ASSERT_TRUE(set2.ParseSysFile(file2.GetFd()));
+  ASSERT_EQ(9, set2.GetCount());
+
+  set1.IntersectWith(set2);
+  ASSERT_EQ(4, set1.GetCount());
+  ASSERT_EQ(9, set2.GetCount());
+}
+
+TEST(CpuSetTest, SelfIntersection) {
+  ScopedTestFile file1("9-19");
+  ASSERT_TRUE(file1.IsOk());
+  CpuSet set1;
+  ASSERT_TRUE(set1.ParseSysFile(file1.GetFd()));
+  ASSERT_EQ(11, set1.GetCount());
+
+  set1.IntersectWith(set1);
+  ASSERT_EQ(11, set1.GetCount());
+}
+
+TEST(CpuSetTest, EmptyIntersection) {
+  ScopedTestFile file1("0-19");
+  ASSERT_TRUE(file1.IsOk());
+  CpuSet set1;
+  ASSERT_TRUE(set1.ParseSysFile(file1.GetFd()));
+  ASSERT_EQ(20, set1.GetCount());
+
+  ScopedTestFile file2("20-39");
+  ASSERT_TRUE(file2.IsOk());
+  CpuSet set2;
+  ASSERT_TRUE(set2.ParseSysFile(file2.GetFd()));
+  ASSERT_EQ(20, set2.GetCount());
+
+  set1.IntersectWith(set2);
+  ASSERT_EQ(0, set1.GetCount());
+
+  ASSERT_EQ(20, set2.GetCount());
+}
+
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/directory_reader.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/directory_reader.h
new file mode 100644
index 0000000000..a4bde18031
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/directory_reader.h
@@ -0,0 +1,106 @@
+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_
+
+#include <stdint.h>
+#include <unistd.h>
+#include <limits.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include "common/linux/linux_libc_support.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+namespace google_breakpad {
+
+// A class for enumerating a directory without using diropen/readdir or other
+// functions which may allocate memory.
+class DirectoryReader {
+ public:
+  DirectoryReader(int fd)
+      : fd_(fd),
+        buf_used_(0) {
+  }
+
+  // Return the next entry from the directory
+  //   name: (output) the NUL terminated entry name
+  //
+  // Returns true iff successful (false on EOF).
+  //
+  // After calling this, one must call |PopEntry| otherwise you'll get the same
+  // entry over and over.
+  bool GetNextEntry(const char** name) {
+    struct kernel_dirent* const dent =
+      reinterpret_cast<kernel_dirent*>(buf_);
+
+    if (buf_used_ == 0) {
+      // need to read more entries.
+      const int n = sys_getdents(fd_, dent, sizeof(buf_));
+      if (n < 0) {
+        return false;
+      } else if (n == 0) {
+        hit_eof_ = true;
+      } else {
+        buf_used_ += n;
+      }
+    }
+
+    if (buf_used_ == 0 && hit_eof_)
+      return false;
+
+    assert(buf_used_ > 0);
+
+    *name = dent->d_name;
+    return true;
+  }
+
+  void PopEntry() {
+    if (!buf_used_)
+      return;
+
+    const struct kernel_dirent* const dent =
+      reinterpret_cast<kernel_dirent*>(buf_);
+
+    buf_used_ -= dent->d_reclen;
+    my_memmove(buf_, buf_ + dent->d_reclen, buf_used_);
+  }
+
+ private:
+  const int fd_;
+  bool hit_eof_;
+  unsigned buf_used_;
+  uint8_t buf_[sizeof(struct kernel_dirent) + NAME_MAX + 1];
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_DIRECTORY_READER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/directory_reader_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/directory_reader_unittest.cc
new file mode 100644
index 0000000000..b33507db95
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/directory_reader_unittest.cc
@@ -0,0 +1,78 @@
+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <set>
+#include <string>
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/types.h>
+
+#include "linux/minidump_writer/directory_reader.h"
+#include "common/using_std_string.h"
+#include "breakpad_googletest_includes.h"
+
+using namespace google_breakpad;
+
+namespace {
+typedef testing::Test DirectoryReaderTest;
+}
+
+TEST(DirectoryReaderTest, CompareResults) {
+  std::set<string> dent_set;
+
+  DIR *const dir = opendir("/proc/self");
+  ASSERT_TRUE(dir != NULL);
+
+  struct dirent* dent;
+  while ((dent = readdir(dir)))
+    dent_set.insert(dent->d_name);
+
+  closedir(dir);
+
+  const int fd = open("/proc/self", O_DIRECTORY | O_RDONLY);
+  ASSERT_GE(fd, 0);
+
+  DirectoryReader dir_reader(fd);
+  unsigned seen = 0;
+
+  const char* name;
+  while (dir_reader.GetNextEntry(&name)) {
+    ASSERT_TRUE(dent_set.find(name) != dent_set.end());
+    seen++;
+    dir_reader.PopEntry();
+  }
+
+  ASSERT_TRUE(dent_set.find("status") != dent_set.end());
+  ASSERT_TRUE(dent_set.find("stat") != dent_set.end());
+  ASSERT_TRUE(dent_set.find("cmdline") != dent_set.end());
+
+  ASSERT_EQ(dent_set.size(), seen);
+  close(fd);
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/line_reader.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/line_reader.h
new file mode 100644
index 0000000000..d8e2dbcc11
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/line_reader.h
@@ -0,0 +1,131 @@
+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_
+
+#include <stdint.h>
+#include <assert.h>
+#include <string.h>
+
+#include "common/linux/linux_libc_support.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+namespace google_breakpad {
+
+// A class for reading a file, line by line, without using fopen/fgets or other
+// functions which may allocate memory.
+class LineReader {
+ public:
+  LineReader(int fd)
+      : fd_(fd),
+        hit_eof_(false),
+        buf_used_(0) {
+  }
+
+  // The maximum length of a line.
+  static const size_t kMaxLineLen = 1024;
+
+  // Return the next line from the file.
+  //   line: (output) a pointer to the start of the line. The line is NUL
+  //     terminated.
+  //   len: (output) the length of the line (not inc the NUL byte)
+  //
+  // Returns true iff successful (false on EOF).
+  //
+  // One must call |PopLine| after this function, otherwise you'll continue to
+  // get the same line over and over.
+  bool GetNextLine(const char **line, unsigned *len) {
+    for (;;) {
+      if (buf_used_ == 0 && hit_eof_)
+        return false;
+
+      for (unsigned i = 0; i < buf_used_; ++i) {
+        if (buf_[i] == '\n' || buf_[i] == 0) {
+          buf_[i] = 0;
+          *len = i;
+          *line = buf_;
+          return true;
+        }
+      }
+
+      if (buf_used_ == sizeof(buf_)) {
+        // we scanned the whole buffer and didn't find an end-of-line marker.
+        // This line is too long to process.
+        return false;
+      }
+
+      // We didn't find any end-of-line terminators in the buffer. However, if
+      // this is the last line in the file it might not have one:
+      if (hit_eof_) {
+        assert(buf_used_);
+        // There's room for the NUL because of the buf_used_ == sizeof(buf_)
+        // check above.
+        buf_[buf_used_] = 0;
+        *len = buf_used_;
+        buf_used_ += 1;  // since we appended the NUL.
+        *line = buf_;
+        return true;
+      }
+
+      // Otherwise, we should pull in more data from the file
+      const ssize_t n = sys_read(fd_, buf_ + buf_used_,
+                                 sizeof(buf_) - buf_used_);
+      if (n < 0) {
+        return false;
+      } else if (n == 0) {
+        hit_eof_ = true;
+      } else {
+        buf_used_ += n;
+      }
+
+      // At this point, we have either set the hit_eof_ flag, or we have more
+      // data to process...
+    }
+  }
+
+  void PopLine(unsigned len) {
+    // len doesn't include the NUL byte at the end.
+
+    assert(buf_used_ >= len + 1);
+    buf_used_ -= len + 1;
+    my_memmove(buf_, buf_ + len + 1, buf_used_);
+  }
+
+ private:
+  const int fd_;
+
+  bool hit_eof_;
+  unsigned buf_used_;
+  char buf_[kMaxLineLen];
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/line_reader_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/line_reader_unittest.cc
new file mode 100644
index 0000000000..576b8b5cdb
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/line_reader_unittest.cc
@@ -0,0 +1,169 @@
+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "linux/minidump_writer/line_reader.h"
+#include "breakpad_googletest_includes.h"
+#include "common/linux/tests/auto_testfile.h"
+
+using namespace google_breakpad;
+
+namespace {
+
+typedef testing::Test LineReaderTest;
+
+class ScopedTestFile : public AutoTestFile {
+public:
+  explicit ScopedTestFile(const char* text)
+    : AutoTestFile("line_reader", text) {
+  }
+
+  ScopedTestFile(const char* text, size_t text_len)
+    : AutoTestFile("line_reader", text, text_len) {
+  }
+};
+
+}
+
+TEST(LineReaderTest, EmptyFile) {
+  ScopedTestFile file("");
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned len;
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+}
+
+TEST(LineReaderTest, OneLineTerminated) {
+  ScopedTestFile file("a\n");
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned int len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ((unsigned int)1, len);
+  ASSERT_EQ('a', line[0]);
+  ASSERT_EQ('\0', line[1]);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+}
+
+TEST(LineReaderTest, OneLine) {
+  ScopedTestFile file("a");
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ((unsigned)1, len);
+  ASSERT_EQ('a', line[0]);
+  ASSERT_EQ('\0', line[1]);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+}
+
+TEST(LineReaderTest, TwoLinesTerminated) {
+  ScopedTestFile file("a\nb\n");
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ((unsigned)1, len);
+  ASSERT_EQ('a', line[0]);
+  ASSERT_EQ('\0', line[1]);
+  reader.PopLine(len);
+
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ((unsigned)1, len);
+  ASSERT_EQ('b', line[0]);
+  ASSERT_EQ('\0', line[1]);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+}
+
+TEST(LineReaderTest, TwoLines) {
+  ScopedTestFile file("a\nb");
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ((unsigned)1, len);
+  ASSERT_EQ('a', line[0]);
+  ASSERT_EQ('\0', line[1]);
+  reader.PopLine(len);
+
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ((unsigned)1, len);
+  ASSERT_EQ('b', line[0]);
+  ASSERT_EQ('\0', line[1]);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+}
+
+TEST(LineReaderTest, MaxLength) {
+  char l[LineReader::kMaxLineLen-1];
+  memset(l, 'a', sizeof(l));
+  ScopedTestFile file(l, sizeof(l));
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(sizeof(l), len);
+  ASSERT_TRUE(memcmp(l, line, sizeof(l)) == 0);
+  ASSERT_EQ('\0', line[len]);
+}
+
+TEST(LineReaderTest, TooLong) {
+  // Note: this writes kMaxLineLen 'a' chars in the test file.
+  char l[LineReader::kMaxLineLen];
+  memset(l, 'a', sizeof(l));
+  ScopedTestFile file(l, sizeof(l));
+  ASSERT_TRUE(file.IsOk());
+  LineReader reader(file.GetFd());
+
+  const char *line;
+  unsigned len;
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper.cc
new file mode 100644
index 0000000000..38feb0aaa7
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper.cc
@@ -0,0 +1,308 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_core_dumper.cc: Implement google_breakpad::LinuxCoreDumper.
+// See linux_core_dumper.h for details.
+
+#include "linux/minidump_writer/linux_core_dumper.h"
+
+#include <asm/ptrace.h>
+#include <assert.h>
+#include <elf.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/procfs.h>
+#if defined(__mips__) && defined(__ANDROID__)
+// To get register definitions.
+#include <asm/reg.h>
+#endif
+
+#include "common/linux/elf_gnu_compat.h"
+#include "common/linux/linux_libc_support.h"
+
+namespace google_breakpad {
+
+LinuxCoreDumper::LinuxCoreDumper(pid_t pid,
+                                 const char* core_path,
+                                 const char* procfs_path,
+                                 const char* root_prefix)
+    : LinuxDumper(pid, root_prefix),
+      core_path_(core_path),
+      procfs_path_(procfs_path),
+      thread_infos_(&allocator_, 8) {
+  assert(core_path_);
+}
+
+bool LinuxCoreDumper::BuildProcPath(char* path, pid_t pid,
+                                    const char* node) const {
+  if (!path || !node)
+    return false;
+
+  size_t node_len = my_strlen(node);
+  if (node_len == 0)
+    return false;
+
+  size_t procfs_path_len = my_strlen(procfs_path_);
+  size_t total_length = procfs_path_len + 1 + node_len;
+  if (total_length >= NAME_MAX)
+    return false;
+
+  memcpy(path, procfs_path_, procfs_path_len);
+  path[procfs_path_len] = '/';
+  memcpy(path + procfs_path_len + 1, node, node_len);
+  path[total_length] = '\0';
+  return true;
+}
+
+bool LinuxCoreDumper::CopyFromProcess(void* dest, pid_t child,
+                                      const void* src, size_t length) {
+  ElfCoreDump::Addr virtual_address = reinterpret_cast<ElfCoreDump::Addr>(src);
+  // TODO(benchan): Investigate whether the data to be copied could span
+  // across multiple segments in the core dump file. ElfCoreDump::CopyData
+  // and this method do not handle that case yet.
+  if (!core_.CopyData(dest, virtual_address, length)) {
+    // If the data segment is not found in the core dump, fill the result
+    // with marker characters.
+    memset(dest, 0xab, length);
+    return false;
+  }
+  return true;
+}
+
+bool LinuxCoreDumper::GetThreadInfoByIndex(size_t index, ThreadInfo* info) {
+  if (index >= thread_infos_.size())
+    return false;
+
+  *info = thread_infos_[index];
+  const uint8_t* stack_pointer;
+#if defined(__i386)
+  memcpy(&stack_pointer, &info->regs.esp, sizeof(info->regs.esp));
+#elif defined(__x86_64)
+  memcpy(&stack_pointer, &info->regs.rsp, sizeof(info->regs.rsp));
+#elif defined(__ARM_EABI__)
+  memcpy(&stack_pointer, &info->regs.ARM_sp, sizeof(info->regs.ARM_sp));
+#elif defined(__aarch64__)
+  memcpy(&stack_pointer, &info->regs.sp, sizeof(info->regs.sp));
+#elif defined(__mips__)
+  stack_pointer =
+      reinterpret_cast<uint8_t*>(info->mcontext.gregs[MD_CONTEXT_MIPS_REG_SP]);
+#else
+#error "This code hasn't been ported to your platform yet."
+#endif
+  info->stack_pointer = reinterpret_cast<uintptr_t>(stack_pointer);
+  return true;
+}
+
+bool LinuxCoreDumper::GetThreadNameByIndex(size_t index, char* name,
+                                           size_t size) {
+  // Not implemented
+  return false;
+}
+
+bool LinuxCoreDumper::IsPostMortem() const {
+  return true;
+}
+
+bool LinuxCoreDumper::ThreadsSuspend() {
+  return true;
+}
+
+bool LinuxCoreDumper::ThreadsResume() {
+  return true;
+}
+
+bool LinuxCoreDumper::EnumerateThreads() {
+  if (!mapped_core_file_.Map(core_path_, 0)) {
+    fprintf(stderr, "Could not map core dump file into memory\n");
+    return false;
+  }
+
+  core_.SetContent(mapped_core_file_.content());
+  if (!core_.IsValid()) {
+    fprintf(stderr, "Invalid core dump file\n");
+    return false;
+  }
+
+  ElfCoreDump::Note note = core_.GetFirstNote();
+  if (!note.IsValid()) {
+    fprintf(stderr, "PT_NOTE section not found\n");
+    return false;
+  }
+
+  bool first_thread = true;
+  do {
+    ElfCoreDump::Word type = note.GetType();
+    MemoryRange name = note.GetName();
+    MemoryRange description = note.GetDescription();
+
+    if (type == 0 || name.IsEmpty() || description.IsEmpty()) {
+      fprintf(stderr, "Could not found a valid PT_NOTE.\n");
+      return false;
+    }
+
+    // Based on write_note_info() in linux/kernel/fs/binfmt_elf.c, notes are
+    // ordered as follows (NT_PRXFPREG and NT_386_TLS are i386 specific):
+    //   Thread           Name          Type
+    //   -------------------------------------------------------------------
+    //   1st thread       CORE          NT_PRSTATUS
+    //   process-wide     CORE          NT_PRPSINFO
+    //   process-wide     CORE          NT_SIGINFO
+    //   process-wide     CORE          NT_AUXV
+    //   1st thread       CORE          NT_FPREGSET
+    //   1st thread       LINUX         NT_PRXFPREG
+    //   1st thread       LINUX         NT_386_TLS
+    //
+    //   2nd thread       CORE          NT_PRSTATUS
+    //   2nd thread       CORE          NT_FPREGSET
+    //   2nd thread       LINUX         NT_PRXFPREG
+    //   2nd thread       LINUX         NT_386_TLS
+    //
+    //   3rd thread       CORE          NT_PRSTATUS
+    //   3rd thread       CORE          NT_FPREGSET
+    //   3rd thread       LINUX         NT_PRXFPREG
+    //   3rd thread       LINUX         NT_386_TLS
+    //
+    // The following code only works if notes are ordered as expected.
+    switch (type) {
+      case NT_PRSTATUS: {
+        if (description.length() != sizeof(elf_prstatus)) {
+          fprintf(stderr, "Found NT_PRSTATUS descriptor of unexpected size\n");
+          return false;
+        }
+
+        const elf_prstatus* status =
+            reinterpret_cast<const elf_prstatus*>(description.data());
+        pid_t pid = status->pr_pid;
+        ThreadInfo info;
+        memset(&info, 0, sizeof(ThreadInfo));
+        info.tgid = status->pr_pgrp;
+        info.ppid = status->pr_ppid;
+#if defined(__mips__)
+#if defined(__ANDROID__)
+        for (int i = EF_R0; i <= EF_R31; i++)
+          info.mcontext.gregs[i - EF_R0] = status->pr_reg[i];
+#else  // __ANDROID__
+        for (int i = EF_REG0; i <= EF_REG31; i++)
+          info.mcontext.gregs[i - EF_REG0] = status->pr_reg[i];
+#endif  // __ANDROID__
+        info.mcontext.mdlo = status->pr_reg[EF_LO];
+        info.mcontext.mdhi = status->pr_reg[EF_HI];
+        info.mcontext.pc = status->pr_reg[EF_CP0_EPC];
+#else  // __mips__
+        memcpy(&info.regs, status->pr_reg, sizeof(info.regs));
+#endif  // __mips__
+        if (first_thread) {
+          crash_thread_ = pid;
+          crash_signal_ = status->pr_info.si_signo;
+          crash_signal_code_ = status->pr_info.si_code;
+        }
+        first_thread = false;
+        threads_.push_back(pid);
+        thread_infos_.push_back(info);
+        break;
+      }
+      case NT_SIGINFO: {
+        if (description.length() != sizeof(siginfo_t)) {
+          fprintf(stderr, "Found NT_SIGINFO descriptor of unexpected size\n");
+          return false;
+        }
+
+        const siginfo_t* info =
+            reinterpret_cast<const siginfo_t*>(description.data());
+
+        // Set crash_address when si_addr is valid for the signal.
+        switch (info->si_signo) {
+          case MD_EXCEPTION_CODE_LIN_SIGBUS:
+          case MD_EXCEPTION_CODE_LIN_SIGFPE:
+          case MD_EXCEPTION_CODE_LIN_SIGILL:
+          case MD_EXCEPTION_CODE_LIN_SIGSEGV:
+          case MD_EXCEPTION_CODE_LIN_SIGSYS:
+          case MD_EXCEPTION_CODE_LIN_SIGTRAP:
+            crash_address_ = reinterpret_cast<uintptr_t>(info->si_addr);
+            break;
+        }
+
+        // Set crash_exception_info for common signals.  Since exception info is
+        // unsigned, but some of these fields might be signed, we always cast.
+        switch (info->si_signo) {
+          case MD_EXCEPTION_CODE_LIN_SIGKILL:
+            set_crash_exception_info({
+              static_cast<uint64_t>(info->si_pid),
+              static_cast<uint64_t>(info->si_uid),
+            });
+            break;
+          case MD_EXCEPTION_CODE_LIN_SIGSYS:
+#ifdef si_syscall
+            set_crash_exception_info({
+              static_cast<uint64_t>(info->si_syscall),
+              static_cast<uint64_t>(info->si_arch),
+            });
+#endif
+            break;
+        }
+        break;
+      }
+#if defined(__i386) || defined(__x86_64)
+      case NT_FPREGSET: {
+        if (thread_infos_.empty())
+          return false;
+
+        ThreadInfo* info = &thread_infos_.back();
+        if (description.length() != sizeof(info->fpregs)) {
+          fprintf(stderr, "Found NT_FPREGSET descriptor of unexpected size\n");
+          return false;
+        }
+
+        memcpy(&info->fpregs, description.data(), sizeof(info->fpregs));
+        break;
+      }
+#endif
+#if defined(__i386)
+      case NT_PRXFPREG: {
+        if (thread_infos_.empty())
+          return false;
+
+        ThreadInfo* info = &thread_infos_.back();
+        if (description.length() != sizeof(info->fpxregs)) {
+          fprintf(stderr, "Found NT_PRXFPREG descriptor of unexpected size\n");
+          return false;
+        }
+
+        memcpy(&info->fpxregs, description.data(), sizeof(info->fpxregs));
+        break;
+      }
+#endif
+    }
+    note = note.GetNextNote();
+  } while (note.IsValid());
+
+  return true;
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper.h
new file mode 100644
index 0000000000..7805854a33
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper.h
@@ -0,0 +1,130 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_core_dumper.h: Define the google_breakpad::LinuxCoreDumper
+// class, which is derived from google_breakpad::LinuxDumper to extract
+// information from a crashed process via its core dump and proc files.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_CORE_DUMPER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_CORE_DUMPER_H_
+
+#include "linux/minidump_writer/linux_dumper.h"
+#include "common/linux/elf_core_dump.h"
+#include "common/linux/memory_mapped_file.h"
+
+namespace google_breakpad {
+
+class LinuxCoreDumper : public LinuxDumper {
+ public:
+  // Constructs a dumper for extracting information of a given process
+  // with a process ID of |pid| via its core dump file at |core_path| and
+  // its proc files at |procfs_path|. If |procfs_path| is a copy of
+  // /proc/<pid>, it should contain the following files:
+  //     auxv, cmdline, environ, exe, maps, status
+  // See LinuxDumper for the purpose of |root_prefix|.
+  LinuxCoreDumper(pid_t pid, const char* core_path, const char* procfs_path,
+                  const char* root_prefix = "");
+
+  // Implements LinuxDumper::BuildProcPath().
+  // Builds a proc path for a certain pid for a node (/proc/<pid>/<node>).
+  // |path| is a character array of at least NAME_MAX bytes to return the
+  // result.|node| is the final node without any slashes. Return true on
+  // success.
+  //
+  // As this dumper performs a post-mortem dump and makes use of a copy
+  // of the proc files of the crashed process, this derived method does
+  // not actually make use of |pid| and always returns a subpath of
+  // |procfs_path_| regardless of whether |pid| corresponds to the main
+  // process or a thread of the process, i.e. assuming both the main process
+  // and its threads have the following proc files with the same content:
+  //     auxv, cmdline, environ, exe, maps, status
+  virtual bool BuildProcPath(char* path, pid_t pid, const char* node) const;
+
+  // Implements LinuxDumper::CopyFromProcess().
+  // Copies content of |length| bytes from a given process |child|,
+  // starting from |src|, into |dest|. This method extracts the content
+  // the core dump and fills |dest| with a sequence of marker bytes
+  // if the expected data is not found in the core dump. Returns true if
+  // the expected data is found in the core dump.
+  virtual bool CopyFromProcess(void* dest, pid_t child, const void* src,
+                               size_t length);
+
+  // Implements LinuxDumper::GetThreadInfoByIndex().
+  // Reads information about the |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadInfoByIndex(size_t index, ThreadInfo* info);
+
+  // Implements LinuxDumper::GetThreadNameByIndex().
+  // Reads the name of the |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadNameByIndex(size_t index, char* info, size_t size);
+
+  // Implements LinuxDumper::IsPostMortem().
+  // Always returns true to indicate that this dumper performs a
+  // post-mortem dump of a crashed process via a core dump file.
+  virtual bool IsPostMortem() const;
+
+  // Implements LinuxDumper::ThreadsSuspend().
+  // As the dumper performs a post-mortem dump via a core dump file,
+  // there is no threads to suspend. This method does nothing and
+  // always returns true.
+  virtual bool ThreadsSuspend();
+
+  // Implements LinuxDumper::ThreadsResume().
+  // As the dumper performs a post-mortem dump via a core dump file,
+  // there is no threads to resume. This method does nothing and
+  // always returns true.
+  virtual bool ThreadsResume();
+
+ protected:
+  // Implements LinuxDumper::EnumerateThreads().
+  // Enumerates all threads of the given process into |threads_|.
+  virtual bool EnumerateThreads();
+
+ private:
+  // Path of the core dump file.
+  const char* core_path_;
+
+  // Path of the directory containing the proc files of the given process,
+  // which is usually a copy of /proc/<pid>.
+  const char* procfs_path_;
+
+  // Memory-mapped core dump file at |core_path_|.
+  MemoryMappedFile mapped_core_file_;
+
+  // Content of the core dump file.
+  ElfCoreDump core_;
+
+  // Thread info found in the core dump file.
+  wasteful_vector<ThreadInfo> thread_infos_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_LINUX_CORE_DUMPER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper_unittest.cc
new file mode 100644
index 0000000000..2e973167fd
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_core_dumper_unittest.cc
@@ -0,0 +1,192 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_core_dumper_unittest.cc:
+// Unit tests for google_breakpad::LinuxCoreDumoer.
+
+#include <string>
+
+#include "breakpad_googletest_includes.h"
+#include "linux/minidump_writer/linux_core_dumper.h"
+#include "common/linux/tests/crash_generator.h"
+#include "common/using_std_string.h"
+
+using namespace google_breakpad;
+
+TEST(LinuxCoreDumperTest, GetMappingAbsolutePath) {
+  const LinuxCoreDumper dumper(getpid(), "core", "/tmp", "/mnt/root");
+  const MappingInfo mapping = {0, 0, {0, 0}, 0, false, "/usr/lib/libc.so"};
+
+  char path[PATH_MAX];
+  dumper.GetMappingAbsolutePath(mapping, path);
+
+  EXPECT_STREQ("/mnt/root/usr/lib/libc.so", path);
+}
+
+TEST(LinuxCoreDumperTest, BuildProcPath) {
+  const pid_t pid = getpid();
+  const char procfs_path[] = "/procfs_copy";
+  LinuxCoreDumper dumper(getpid(), "core_file", procfs_path);
+
+  char maps_path[NAME_MAX] = "";
+  char maps_path_expected[NAME_MAX];
+  snprintf(maps_path_expected, sizeof(maps_path_expected),
+           "%s/maps", procfs_path);
+  EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
+  EXPECT_STREQ(maps_path_expected, maps_path);
+
+  EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
+
+  char long_node[NAME_MAX];
+  size_t long_node_len = NAME_MAX - strlen(procfs_path) - 1;
+  memset(long_node, 'a', long_node_len);
+  long_node[long_node_len] = '\0';
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, long_node));
+}
+
+TEST(LinuxCoreDumperTest, VerifyDumpWithMultipleThreads) {
+  CrashGenerator crash_generator;
+  if (!crash_generator.HasDefaultCorePattern()) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test "
+            "is skipped due to non-default core pattern\n");
+    return;
+  }
+
+  const unsigned kNumOfThreads = 3;
+  const unsigned kCrashThread = 1;
+  const int kCrashSignal = SIGABRT;
+  pid_t child_pid;
+  ASSERT_TRUE(crash_generator.CreateChildCrash(kNumOfThreads, kCrashThread,
+                                               kCrashSignal, &child_pid));
+
+  const string core_file = crash_generator.GetCoreFilePath();
+  const string procfs_path = crash_generator.GetDirectoryOfProcFilesCopy();
+
+#if defined(__ANDROID__)
+  struct stat st;
+  if (stat(core_file.c_str(), &st) != 0) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test is "
+            "skipped due to no core file being generated\n");
+    return;
+  }
+#endif
+
+  LinuxCoreDumper dumper(child_pid, core_file.c_str(), procfs_path.c_str());
+
+  EXPECT_TRUE(dumper.Init());
+
+  EXPECT_TRUE(dumper.IsPostMortem());
+
+  // These are no-ops and should always return true.
+  EXPECT_TRUE(dumper.ThreadsSuspend());
+  EXPECT_TRUE(dumper.ThreadsResume());
+
+  // Linux does not set the crash address with SIGABRT, so make sure it always
+  // sets the crash address to 0.
+  EXPECT_EQ(0U, dumper.crash_address());
+  EXPECT_EQ(kCrashSignal, dumper.crash_signal());
+  EXPECT_EQ(crash_generator.GetThreadId(kCrashThread),
+            dumper.crash_thread());
+
+#if defined(THREAD_SANITIZER)
+  EXPECT_GE(dumper.threads().size(), kNumOfThreads);
+#else
+  EXPECT_EQ(dumper.threads().size(), kNumOfThreads);
+#endif
+  for (unsigned i = 0; i < kNumOfThreads; ++i) {
+    ThreadInfo info;
+    EXPECT_TRUE(dumper.GetThreadInfoByIndex(i, &info));
+    const void* stack;
+    size_t stack_len;
+    EXPECT_TRUE(dumper.GetStackInfo(&stack, &stack_len, info.stack_pointer));
+    EXPECT_EQ(getpid(), info.ppid);
+  }
+}
+
+TEST(LinuxCoreDumperTest, VerifyExceptionDetails) {
+  CrashGenerator crash_generator;
+  if (!crash_generator.HasDefaultCorePattern()) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test "
+            "is skipped due to non-default core pattern\n");
+    return;
+  }
+
+#ifndef si_syscall
+  fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test is "
+          "skipped due to old kernel/C library headers\n");
+  return;
+#endif
+
+  const unsigned kNumOfThreads = 2;
+  const unsigned kCrashThread = 1;
+  const int kCrashSignal = SIGSYS;
+  pid_t child_pid;
+  ASSERT_TRUE(crash_generator.CreateChildCrash(kNumOfThreads, kCrashThread,
+                                               kCrashSignal, &child_pid));
+
+  const string core_file = crash_generator.GetCoreFilePath();
+  const string procfs_path = crash_generator.GetDirectoryOfProcFilesCopy();
+
+#if defined(__ANDROID__)
+  struct stat st;
+  if (stat(core_file.c_str(), &st) != 0) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyExceptionDetails test is "
+            "skipped due to no core file being generated\n");
+    return;
+  }
+#endif
+
+  LinuxCoreDumper dumper(child_pid, core_file.c_str(), procfs_path.c_str());
+
+  EXPECT_TRUE(dumper.Init());
+
+  EXPECT_TRUE(dumper.IsPostMortem());
+
+#if defined(__ANDROID__)
+  // TODO: For some reason, Android doesn't seem to pass this.
+  if (!dumper.crash_address()) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyExceptionDetails test is "
+            "skipped due to missing signal details on Android\n");
+    return;
+  }
+#endif
+
+  // Check the exception details.
+  EXPECT_NE(0U, dumper.crash_address());
+  EXPECT_EQ(kCrashSignal, dumper.crash_signal());
+  EXPECT_EQ(crash_generator.GetThreadId(kCrashThread),
+            dumper.crash_thread());
+
+  // We check the length, but not the actual fields.  We sent SIGSYS ourselves
+  // instead of the kernel, so the extended fields are garbage.
+  const std::vector<uint64_t> info(dumper.crash_exception_info());
+  EXPECT_EQ(2U, info.size());
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper.cc
new file mode 100644
index 0000000000..3b400ce8ca
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper.cc
@@ -0,0 +1,999 @@
+// Copyright (c) 2010, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_dumper.cc: Implement google_breakpad::LinuxDumper.
+// See linux_dumper.h for details.
+
+// This code deals with the mechanics of getting information about a crashed
+// process. Since this code may run in a compromised address space, the same
+// rules apply as detailed at the top of minidump_writer.h: no libc calls and
+// use the alternative allocator.
+
+#include "linux/minidump_writer/linux_dumper.h"
+
+#include <assert.h>
+#include <elf.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "linux/minidump_writer/line_reader.h"
+#include "common/linux/elfutils.h"
+#include "common/linux/file_id.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/linux/memory_mapped_file.h"
+#include "common/linux/safe_readlink.h"
+#include "google_breakpad/common/minidump_exception_linux.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+#if defined(__ANDROID__)
+
+// Android packed relocations definitions are not yet available from the
+// NDK header files, so we have to provide them manually here.
+#ifndef DT_LOOS
+#define DT_LOOS 0x6000000d
+#endif
+#ifndef DT_ANDROID_REL
+static const int DT_ANDROID_REL = DT_LOOS + 2;
+#endif
+#ifndef DT_ANDROID_RELA
+static const int DT_ANDROID_RELA = DT_LOOS + 4;
+#endif
+
+#endif  // __ANDROID __
+
+static const char kMappedFileUnsafePrefix[] = "/dev/";
+static const char kDeletedSuffix[] = " (deleted)";
+static const char kReservedFlags[] = " ---p";
+static const char kMozillaIpcPrefix[] = "org.mozilla.ipc.";
+
+inline static bool IsMappedFileOpenUnsafe(
+    const google_breakpad::MappingInfo& mapping) {
+  // It is unsafe to attempt to open a mapped file that lives under /dev,
+  // because the semantics of the open may be driver-specific so we'd risk
+  // hanging the crash dumper. And a file in /dev/ almost certainly has no
+  // ELF file identifier anyways.
+  return my_strncmp(mapping.name,
+                    kMappedFileUnsafePrefix,
+                    sizeof(kMappedFileUnsafePrefix) - 1) == 0;
+}
+
+namespace google_breakpad {
+
+namespace {
+
+bool MappingContainsAddress(const MappingInfo& mapping, uintptr_t address) {
+  return mapping.system_mapping_info.start_addr <= address &&
+         address < mapping.system_mapping_info.end_addr;
+}
+
+#if defined(__CHROMEOS__)
+
+// Recover memory mappings before writing dump on ChromeOS
+//
+// On Linux, breakpad relies on /proc/[pid]/maps to associate symbols from
+// addresses. ChromeOS' hugepage implementation replaces some segments with
+// anonymous private pages, which is a restriction of current implementation
+// in Linux kernel at the time of writing. Thus, breakpad can no longer
+// symbolize addresses from those text segments replaced with hugepages.
+//
+// This postprocess tries to recover the mappings. Because hugepages are always
+// inserted in between some .text sections, it tries to infer the names and
+// offsets of the segments, by looking at segments immediately precede and
+// succeed them.
+//
+// For example, a text segment before hugepage optimization
+//   02001000-03002000 r-xp /opt/google/chrome/chrome
+//
+// can be broken into
+//   02001000-02200000 r-xp /opt/google/chrome/chrome
+//   02200000-03000000 r-xp
+//   03000000-03002000 r-xp /opt/google/chrome/chrome
+//
+// For more details, see:
+// crbug.com/628040 ChromeOS' use of hugepages confuses crash symbolization
+
+// Copied from CrOS' hugepage implementation, which is unlikely to change.
+// The hugepage size is 2M.
+const unsigned int kHpageShift = 21;
+const size_t kHpageSize = (1 << kHpageShift);
+const size_t kHpageMask = (~(kHpageSize - 1));
+
+// Find and merge anonymous r-xp segments with surrounding named segments.
+// There are two cases:
+
+// Case 1: curr, next
+//   curr is anonymous
+//   curr is r-xp
+//   curr.size >= 2M
+//   curr.size is a multiple of 2M.
+//   next is backed by some file.
+//   curr and next are contiguous.
+//   offset(next) == sizeof(curr)
+void TryRecoverMappings(MappingInfo *curr, MappingInfo *next) {
+  // Merged segments are marked with size = 0.
+  if (curr->size == 0 || next->size == 0)
+    return;
+
+  if (curr->size >= kHpageSize &&
+      curr->exec &&
+      (curr->size & kHpageMask) == curr->size &&
+      (curr->start_addr & kHpageMask) == curr->start_addr &&
+      curr->name[0] == '\0' &&
+      next->name[0] != '\0' &&
+      curr->start_addr + curr->size == next->start_addr &&
+      curr->size == next->offset) {
+
+    // matched
+    my_strlcpy(curr->name, next->name, NAME_MAX);
+    if (next->exec) {
+      // (curr, next)
+      curr->size += next->size;
+      next->size = 0;
+    }
+  }
+}
+
+// Case 2: prev, curr, next
+//   curr is anonymous
+//   curr is r-xp
+//   curr.size >= 2M
+//   curr.size is a multiple of 2M.
+//   next and prev are backed by the same file.
+//   prev, curr and next are contiguous.
+//   offset(next) == offset(prev) + sizeof(prev) + sizeof(curr)
+void TryRecoverMappings(MappingInfo *prev, MappingInfo *curr,
+    MappingInfo *next) {
+  // Merged segments are marked with size = 0.
+  if (prev->size == 0 || curr->size == 0 || next->size == 0)
+    return;
+
+  if (curr->size >= kHpageSize &&
+      curr->exec &&
+      (curr->size & kHpageMask) == curr->size &&
+      (curr->start_addr & kHpageMask) == curr->start_addr &&
+      curr->name[0] == '\0' &&
+      next->name[0] != '\0' &&
+      curr->start_addr + curr->size == next->start_addr &&
+      prev->start_addr + prev->size == curr->start_addr &&
+      my_strncmp(prev->name, next->name, NAME_MAX) == 0 &&
+      next->offset == prev->offset + prev->size + curr->size) {
+
+    // matched
+    my_strlcpy(curr->name, prev->name, NAME_MAX);
+    if (prev->exec) {
+      curr->offset = prev->offset;
+      curr->start_addr = prev->start_addr;
+      if (next->exec) {
+        // (prev, curr, next)
+        curr->size += prev->size + next->size;
+        prev->size = 0;
+        next->size = 0;
+      } else {
+        // (prev, curr), next
+        curr->size += prev->size;
+        prev->size = 0;
+      }
+    } else {
+      curr->offset = prev->offset + prev->size;
+      if (next->exec) {
+        // prev, (curr, next)
+        curr->size += next->size;
+        next->size = 0;
+      } else {
+        // prev, curr, next
+      }
+    }
+  }
+}
+
+// mappings_ is sorted excepted for the first entry.
+// This function tries to merge segemnts into the first entry,
+// then check for other sorted entries.
+// See LinuxDumper::EnumerateMappings().
+void CrOSPostProcessMappings(wasteful_vector<MappingInfo*>& mappings) {
+  // Find the candidate "next" to first segment, which is the only one that
+  // could be out-of-order.
+  size_t l = 1;
+  size_t r = mappings.size();
+  size_t next = mappings.size();
+  while (l < r) {
+    int m = (l + r) / 2;
+    if (mappings[m]->start_addr > mappings[0]->start_addr)
+      r = next = m;
+    else
+      l = m + 1;
+  }
+
+  // Shows the range that contains the entry point is
+  // [first_start_addr, first_end_addr)
+  size_t first_start_addr = mappings[0]->start_addr;
+  size_t first_end_addr = mappings[0]->start_addr + mappings[0]->size;
+
+  // Put the out-of-order segment in order.
+  std::rotate(mappings.begin(), mappings.begin() + 1, mappings.begin() + next);
+
+  // Iterate through normal, sorted cases.
+  // Normal case 1.
+  for (size_t i = 0; i < mappings.size() - 1; i++)
+    TryRecoverMappings(mappings[i], mappings[i + 1]);
+
+  // Normal case 2.
+  for (size_t i = 0; i < mappings.size() - 2; i++)
+    TryRecoverMappings(mappings[i], mappings[i + 1], mappings[i + 2]);
+
+  // Collect merged (size == 0) segments.
+  size_t f, e;
+  for (f = e = 0; e < mappings.size(); e++)
+    if (mappings[e]->size > 0)
+      mappings[f++] = mappings[e];
+  mappings.resize(f);
+
+  // The entry point is in the first mapping. We want to find the location
+  // of the entry point after merging segment. To do this, we want to find
+  // the mapping that covers the first mapping from the original mapping list.
+  // If the mapping is not in the beginning, we move it to the begining via
+  // a right rotate by using reverse iterators.
+  for (l = 0; l < mappings.size(); l++) {
+    if (mappings[l]->start_addr <= first_start_addr
+        && (mappings[l]->start_addr + mappings[l]->size >= first_end_addr))
+      break;
+  }
+  if (l > 0) {
+    r = mappings.size();
+    std::rotate(mappings.rbegin() + r - l - 1, mappings.rbegin() + r - l,
+                mappings.rend());
+  }
+}
+
+#endif  // __CHROMEOS__
+
+}  // namespace
+
+// All interesting auvx entry types are below AT_SYSINFO_EHDR
+#define AT_MAX AT_SYSINFO_EHDR
+
+LinuxDumper::LinuxDumper(pid_t pid, const char* root_prefix)
+    : pid_(pid),
+      root_prefix_(root_prefix),
+      crash_address_(0),
+      crash_signal_(0),
+      crash_signal_code_(0),
+      crash_thread_(pid),
+      threads_(&allocator_, 8),
+      mappings_(&allocator_),
+      auxv_(&allocator_, AT_MAX + 1) {
+  assert(root_prefix_ && my_strlen(root_prefix_) < PATH_MAX);
+  // The passed-in size to the constructor (above) is only a hint.
+  // Must call .resize() to do actual initialization of the elements.
+  auxv_.resize(AT_MAX + 1);
+}
+
+LinuxDumper::~LinuxDumper() {
+}
+
+bool LinuxDumper::Init() {
+  return ReadAuxv() && EnumerateThreads() && EnumerateMappings();
+}
+
+bool LinuxDumper::LateInit() {
+#if defined(__ANDROID__)
+  LatePostprocessMappings();
+#endif
+
+#if defined(__CHROMEOS__)
+  CrOSPostProcessMappings(mappings_);
+#endif
+
+  return true;
+}
+
+bool
+LinuxDumper::ElfFileIdentifierForMapping(const MappingInfo& mapping,
+                                         bool member,
+                                         unsigned int mapping_id,
+                                         wasteful_vector<uint8_t>& identifier) {
+  assert(!member || mapping_id < mappings_.size());
+  if (IsMappedFileOpenUnsafe(mapping))
+    return false;
+
+  // Special-case linux-gate because it's not a real file.
+  if (my_strcmp(mapping.name, kLinuxGateLibraryName) == 0) {
+    void* linux_gate = NULL;
+    if (pid_ == sys_getpid()) {
+      linux_gate = reinterpret_cast<void*>(mapping.start_addr);
+    } else {
+      linux_gate = allocator_.Alloc(mapping.size);
+      CopyFromProcess(linux_gate, pid_,
+                      reinterpret_cast<const void*>(mapping.start_addr),
+                      mapping.size);
+    }
+    return FileID::ElfFileIdentifierFromMappedFile(linux_gate, identifier);
+  }
+
+  char filename[PATH_MAX];
+  if (!GetMappingAbsolutePath(mapping, filename))
+    return false;
+  bool filename_modified = HandleDeletedFileInMapping(filename);
+
+  MemoryMappedFile mapped_file(filename, mapping.offset);
+  if (!mapped_file.data() || mapped_file.size() < SELFMAG)
+    return false;
+
+  bool success =
+      FileID::ElfFileIdentifierFromMappedFile(mapped_file.data(), identifier);
+  if (success && member && filename_modified) {
+    mappings_[mapping_id]->name[my_strlen(mapping.name) -
+                                sizeof(kDeletedSuffix) + 1] = '\0';
+  }
+
+  return success;
+}
+
+void LinuxDumper::SetCrashInfoFromSigInfo(const siginfo_t& siginfo) {
+  set_crash_address(reinterpret_cast<uintptr_t>(siginfo.si_addr));
+  set_crash_signal(siginfo.si_signo);
+  set_crash_signal_code(siginfo.si_code);
+}
+
+const char* LinuxDumper::GetCrashSignalString() const {
+  switch (static_cast<unsigned int>(crash_signal_)) {
+    case MD_EXCEPTION_CODE_LIN_SIGHUP:
+      return "SIGHUP";
+    case MD_EXCEPTION_CODE_LIN_SIGINT:
+      return "SIGINT";
+    case MD_EXCEPTION_CODE_LIN_SIGQUIT:
+      return "SIGQUIT";
+    case MD_EXCEPTION_CODE_LIN_SIGILL:
+      return "SIGILL";
+    case MD_EXCEPTION_CODE_LIN_SIGTRAP:
+      return "SIGTRAP";
+    case MD_EXCEPTION_CODE_LIN_SIGABRT:
+      return "SIGABRT";
+    case MD_EXCEPTION_CODE_LIN_SIGBUS:
+      return "SIGBUS";
+    case MD_EXCEPTION_CODE_LIN_SIGFPE:
+      return "SIGFPE";
+    case MD_EXCEPTION_CODE_LIN_SIGKILL:
+      return "SIGKILL";
+    case MD_EXCEPTION_CODE_LIN_SIGUSR1:
+      return "SIGUSR1";
+    case MD_EXCEPTION_CODE_LIN_SIGSEGV:
+      return "SIGSEGV";
+    case MD_EXCEPTION_CODE_LIN_SIGUSR2:
+      return "SIGUSR2";
+    case MD_EXCEPTION_CODE_LIN_SIGPIPE:
+      return "SIGPIPE";
+    case MD_EXCEPTION_CODE_LIN_SIGALRM:
+      return "SIGALRM";
+    case MD_EXCEPTION_CODE_LIN_SIGTERM:
+      return "SIGTERM";
+    case MD_EXCEPTION_CODE_LIN_SIGSTKFLT:
+      return "SIGSTKFLT";
+    case MD_EXCEPTION_CODE_LIN_SIGCHLD:
+      return "SIGCHLD";
+    case MD_EXCEPTION_CODE_LIN_SIGCONT:
+      return "SIGCONT";
+    case MD_EXCEPTION_CODE_LIN_SIGSTOP:
+      return "SIGSTOP";
+    case MD_EXCEPTION_CODE_LIN_SIGTSTP:
+      return "SIGTSTP";
+    case MD_EXCEPTION_CODE_LIN_SIGTTIN:
+      return "SIGTTIN";
+    case MD_EXCEPTION_CODE_LIN_SIGTTOU:
+      return "SIGTTOU";
+    case MD_EXCEPTION_CODE_LIN_SIGURG:
+      return "SIGURG";
+    case MD_EXCEPTION_CODE_LIN_SIGXCPU:
+      return "SIGXCPU";
+    case MD_EXCEPTION_CODE_LIN_SIGXFSZ:
+      return "SIGXFSZ";
+    case MD_EXCEPTION_CODE_LIN_SIGVTALRM:
+      return "SIGVTALRM";
+    case MD_EXCEPTION_CODE_LIN_SIGPROF:
+      return "SIGPROF";
+    case MD_EXCEPTION_CODE_LIN_SIGWINCH:
+      return "SIGWINCH";
+    case MD_EXCEPTION_CODE_LIN_SIGIO:
+      return "SIGIO";
+    case MD_EXCEPTION_CODE_LIN_SIGPWR:
+      return "SIGPWR";
+    case MD_EXCEPTION_CODE_LIN_SIGSYS:
+      return "SIGSYS";
+    case MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED:
+      return "DUMP_REQUESTED";
+    default:
+      return "UNKNOWN";
+  }
+}
+
+bool LinuxDumper::GetMappingAbsolutePath(const MappingInfo& mapping,
+                                         char path[PATH_MAX]) const {
+  return my_strlcpy(path, root_prefix_, PATH_MAX) < PATH_MAX &&
+         my_strlcat(path, mapping.name, PATH_MAX) < PATH_MAX;
+}
+
+namespace {
+// Find the shared object name (SONAME) by examining the ELF information
+// for |mapping|. If the SONAME is found copy it into the passed buffer
+// |soname| and return true. The size of the buffer is |soname_size|.
+// The SONAME will be truncated if it is too long to fit in the buffer.
+bool ElfFileSoName(const LinuxDumper& dumper,
+    const MappingInfo& mapping, char* soname, size_t soname_size) {
+  if (IsMappedFileOpenUnsafe(mapping)) {
+    // Not safe
+    return false;
+  }
+
+  char filename[PATH_MAX];
+  if (!dumper.GetMappingAbsolutePath(mapping, filename))
+    return false;
+
+  MemoryMappedFile mapped_file(filename, mapping.offset);
+  if (!mapped_file.data() || mapped_file.size() < SELFMAG) {
+    // mmap failed
+    return false;
+  }
+
+  return ElfFileSoNameFromMappedFile(mapped_file.data(), soname, soname_size);
+}
+
+}  // namespace
+
+
+void LinuxDumper::GetMappingEffectiveNameAndPath(const MappingInfo& mapping,
+                                                 char* file_path,
+                                                 size_t file_path_size,
+                                                 char* file_name,
+                                                 size_t file_name_size) {
+  my_strlcpy(file_path, mapping.name, file_path_size);
+
+  // Tools such as minidump_stackwalk use the name of the module to look up
+  // symbols produced by dump_syms. dump_syms will prefer to use a module's
+  // DT_SONAME as the module name, if one exists, and will fall back to the
+  // filesystem name of the module.
+
+  // Just use the filesystem name if no SONAME is present.
+  if (!ElfFileSoName(*this, mapping, file_name, file_name_size)) {
+    //   file_path := /path/to/libname.so
+    //   file_name := libname.so
+    const char* basename = my_strrchr(file_path, '/');
+    basename = basename == NULL ? file_path : (basename + 1);
+    my_strlcpy(file_name, basename, file_name_size);
+    return;
+  }
+
+  if (mapping.exec && mapping.offset != 0) {
+    // If an executable is mapped from a non-zero offset, this is likely because
+    // the executable was loaded directly from inside an archive file (e.g., an
+    // apk on Android).
+    // In this case, we append the file_name to the mapped archive path:
+    //   file_name := libname.so
+    //   file_path := /path/to/ARCHIVE.APK/libname.so
+    if (my_strlen(file_path) + 1 + my_strlen(file_name) < file_path_size) {
+      my_strlcat(file_path, "/", file_path_size);
+      my_strlcat(file_path, file_name, file_path_size);
+    }
+  } else {
+    // Otherwise, replace the basename with the SONAME.
+    char* basename = const_cast<char*>(my_strrchr(file_path, '/'));
+    if (basename) {
+      my_strlcpy(basename + 1, file_name,
+                 file_path_size - my_strlen(file_path) +
+                     my_strlen(basename + 1));
+    } else {
+      my_strlcpy(file_path, file_name, file_path_size);
+    }
+  }
+}
+
+bool LinuxDumper::ReadAuxv() {
+  char auxv_path[NAME_MAX];
+  if (!BuildProcPath(auxv_path, pid_, "auxv")) {
+    return false;
+  }
+
+  int fd = sys_open(auxv_path, O_RDONLY, 0);
+  if (fd < 0) {
+    return false;
+  }
+
+  elf_aux_entry one_aux_entry;
+  bool res = false;
+  while (sys_read(fd,
+                  &one_aux_entry,
+                  sizeof(elf_aux_entry)) == sizeof(elf_aux_entry) &&
+         one_aux_entry.a_type != AT_NULL) {
+    if (one_aux_entry.a_type <= AT_MAX) {
+      auxv_[one_aux_entry.a_type] = one_aux_entry.a_un.a_val;
+      res = true;
+    }
+  }
+  sys_close(fd);
+  return res;
+}
+
+bool LinuxDumper::IsIPCSharedMemorySegment(const char* name) {
+  if (my_strstr(name, kMozillaIpcPrefix) &&
+      my_strstr(name, kDeletedSuffix)) {
+    return true;
+  }
+
+  return false;
+}
+
+bool LinuxDumper::EnumerateMappings() {
+  char maps_path[NAME_MAX];
+  if (!BuildProcPath(maps_path, pid_, "maps"))
+    return false;
+
+  // linux_gate_loc is the beginning of the kernel's mapping of
+  // linux-gate.so in the process.  It doesn't actually show up in the
+  // maps list as a filename, but it can be found using the AT_SYSINFO_EHDR
+  // aux vector entry, which gives the information necessary to special
+  // case its entry when creating the list of mappings.
+  // See http://www.trilithium.com/johan/2005/08/linux-gate/ for more
+  // information.
+  const void* linux_gate_loc =
+      reinterpret_cast<void *>(auxv_[AT_SYSINFO_EHDR]);
+  // Although the initial executable is usually the first mapping, it's not
+  // guaranteed (see http://crosbug.com/25355); therefore, try to use the
+  // actual entry point to find the mapping.
+  const void* entry_point_loc = reinterpret_cast<void *>(auxv_[AT_ENTRY]);
+
+  const int fd = sys_open(maps_path, O_RDONLY, 0);
+  if (fd < 0)
+    return false;
+  LineReader* const line_reader = new(allocator_) LineReader(fd);
+
+  const char* line;
+  unsigned line_len;
+  while (line_reader->GetNextLine(&line, &line_len)) {
+    uintptr_t start_addr, end_addr, offset;
+
+    const char* i1 = my_read_hex_ptr(&start_addr, line);
+    if (*i1 == '-') {
+      const char* i2 = my_read_hex_ptr(&end_addr, i1 + 1);
+      if (*i2 == ' ') {
+        bool exec = (*(i2 + 3) == 'x');
+        const char* i3 = my_read_hex_ptr(&offset, i2 + 6 /* skip ' rwxp ' */);
+        if (*i3 == ' ') {
+          const char* name = NULL;
+          // Only copy name if the name is a valid path name, or if
+          // it's the VDSO image.
+          if (((name = my_strchr(line, '/')) == NULL) &&
+              linux_gate_loc &&
+              reinterpret_cast<void*>(start_addr) == linux_gate_loc) {
+            name = kLinuxGateLibraryName;
+            offset = 0;
+          }
+          // Skip shared memory segments used for IPC
+          if (name && IsIPCSharedMemorySegment(name)) {
+            line_reader->PopLine(line_len);
+            continue;
+          }
+          // Merge adjacent mappings into one module, assuming they're a single
+          // library mapped by the dynamic linker.
+          if (name && !mappings_.empty()) {
+            MappingInfo* module = mappings_.back();
+            if ((start_addr == module->start_addr + module->size) &&
+                (my_strlen(name) == my_strlen(module->name)) &&
+                (my_strncmp(name, module->name, my_strlen(name)) == 0)) {
+              module->system_mapping_info.end_addr = end_addr;
+              module->size = end_addr - module->start_addr;
+              module->exec |= exec;
+              line_reader->PopLine(line_len);
+              continue;
+            }
+          }
+          // Also merge mappings that result from address ranges that the
+          // linker reserved but which a loaded library did not use. These
+          // appear as an anonymous private mapping with no access flags set
+          // and which directly follow an executable mapping.
+          if (!name && !mappings_.empty()) {
+            MappingInfo* module = mappings_.back();
+            uintptr_t module_end_addr = module->start_addr + module->size;
+            if ((start_addr == module_end_addr) &&
+                module->exec &&
+                module->name[0] == '/' &&
+                ((offset == 0) || (offset == module_end_addr)) &&
+                my_strncmp(i2, kReservedFlags,
+                           sizeof(kReservedFlags) - 1) == 0) {
+              module->size = end_addr - module->start_addr;
+              line_reader->PopLine(line_len);
+              continue;
+            }
+          }
+          MappingInfo* const module = new(allocator_) MappingInfo;
+          mappings_.push_back(module);
+          my_memset(module, 0, sizeof(MappingInfo));
+          module->system_mapping_info.start_addr = start_addr;
+          module->system_mapping_info.end_addr = end_addr;
+          module->start_addr = start_addr;
+          module->size = end_addr - start_addr;
+          module->offset = offset;
+          module->exec = exec;
+          if (name != NULL) {
+            const unsigned l = my_strlen(name);
+            if (l < sizeof(module->name))
+              my_memcpy(module->name, name, l);
+          }
+        }
+      }
+    }
+    line_reader->PopLine(line_len);
+  }
+
+  if (entry_point_loc) {
+    for (size_t i = 0; i < mappings_.size(); ++i) {
+      MappingInfo* module = mappings_[i];
+
+      // If this module contains the entry-point, and it's not already the first
+      // one, then we need to make it be first.  This is because the minidump
+      // format assumes the first module is the one that corresponds to the main
+      // executable (as codified in
+      // processor/minidump.cc:MinidumpModuleList::GetMainModule()).
+      if ((entry_point_loc >= reinterpret_cast<void*>(module->start_addr)) &&
+          (entry_point_loc <
+           reinterpret_cast<void*>(module->start_addr + module->size))) {
+        for (size_t j = i; j > 0; j--)
+          mappings_[j] = mappings_[j - 1];
+        mappings_[0] = module;
+        break;
+      }
+    }
+  }
+
+  sys_close(fd);
+
+  return !mappings_.empty();
+}
+
+#if defined(__ANDROID__)
+
+bool LinuxDumper::GetLoadedElfHeader(uintptr_t start_addr, ElfW(Ehdr)* ehdr) {
+  CopyFromProcess(ehdr, pid_,
+                  reinterpret_cast<const void*>(start_addr),
+                  sizeof(*ehdr));
+  return my_memcmp(&ehdr->e_ident, ELFMAG, SELFMAG) == 0;
+}
+
+void LinuxDumper::ParseLoadedElfProgramHeaders(ElfW(Ehdr)* ehdr,
+                                               uintptr_t start_addr,
+                                               uintptr_t* min_vaddr_ptr,
+                                               uintptr_t* dyn_vaddr_ptr,
+                                               size_t* dyn_count_ptr) {
+  uintptr_t phdr_addr = start_addr + ehdr->e_phoff;
+
+  const uintptr_t max_addr = UINTPTR_MAX;
+  uintptr_t min_vaddr = max_addr;
+  uintptr_t dyn_vaddr = 0;
+  size_t dyn_count = 0;
+
+  for (size_t i = 0; i < ehdr->e_phnum; ++i) {
+    ElfW(Phdr) phdr;
+    CopyFromProcess(&phdr, pid_,
+                    reinterpret_cast<const void*>(phdr_addr),
+                    sizeof(phdr));
+    if (phdr.p_type == PT_LOAD && phdr.p_vaddr < min_vaddr) {
+      min_vaddr = phdr.p_vaddr;
+    }
+    if (phdr.p_type == PT_DYNAMIC) {
+      dyn_vaddr = phdr.p_vaddr;
+      dyn_count = phdr.p_memsz / sizeof(ElfW(Dyn));
+    }
+    phdr_addr += sizeof(phdr);
+  }
+
+  *min_vaddr_ptr = min_vaddr;
+  *dyn_vaddr_ptr = dyn_vaddr;
+  *dyn_count_ptr = dyn_count;
+}
+
+bool LinuxDumper::HasAndroidPackedRelocations(uintptr_t load_bias,
+                                              uintptr_t dyn_vaddr,
+                                              size_t dyn_count) {
+  uintptr_t dyn_addr = load_bias + dyn_vaddr;
+  for (size_t i = 0; i < dyn_count; ++i) {
+    ElfW(Dyn) dyn;
+    CopyFromProcess(&dyn, pid_,
+                    reinterpret_cast<const void*>(dyn_addr),
+                    sizeof(dyn));
+    if (dyn.d_tag == DT_ANDROID_REL || dyn.d_tag == DT_ANDROID_RELA) {
+      return true;
+    }
+    dyn_addr += sizeof(dyn);
+  }
+  return false;
+}
+
+uintptr_t LinuxDumper::GetEffectiveLoadBias(ElfW(Ehdr)* ehdr,
+                                            uintptr_t start_addr) {
+  uintptr_t min_vaddr = 0;
+  uintptr_t dyn_vaddr = 0;
+  size_t dyn_count = 0;
+  ParseLoadedElfProgramHeaders(ehdr, start_addr,
+                               &min_vaddr, &dyn_vaddr, &dyn_count);
+  // If |min_vaddr| is non-zero and we find Android packed relocation tags,
+  // return the effective load bias.
+  if (min_vaddr != 0) {
+    const uintptr_t load_bias = start_addr - min_vaddr;
+    if (HasAndroidPackedRelocations(load_bias, dyn_vaddr, dyn_count)) {
+      return load_bias;
+    }
+  }
+  // Either |min_vaddr| is zero, or it is non-zero but we did not find the
+  // expected Android packed relocations tags.
+  return start_addr;
+}
+
+void LinuxDumper::LatePostprocessMappings() {
+  for (size_t i = 0; i < mappings_.size(); ++i) {
+    // Only consider exec mappings that indicate a file path was mapped, and
+    // where the ELF header indicates a mapped shared library.
+    MappingInfo* mapping = mappings_[i];
+    if (!(mapping->exec && mapping->name[0] == '/')) {
+      continue;
+    }
+    ElfW(Ehdr) ehdr;
+    if (!GetLoadedElfHeader(mapping->start_addr, &ehdr)) {
+      continue;
+    }
+    if (ehdr.e_type == ET_DYN) {
+      // Compute the effective load bias for this mapped library, and update
+      // the mapping to hold that rather than |start_addr|, at the same time
+      // adjusting |size| to account for the change in |start_addr|. Where
+      // the library does not contain Android packed relocations,
+      // GetEffectiveLoadBias() returns |start_addr| and the mapping entry
+      // is not changed.
+      const uintptr_t load_bias = GetEffectiveLoadBias(&ehdr,
+                                                       mapping->start_addr);
+      mapping->size += mapping->start_addr - load_bias;
+      mapping->start_addr = load_bias;
+    }
+  }
+}
+
+#endif  // __ANDROID__
+
+// Get information about the stack, given the stack pointer. We don't try to
+// walk the stack since we might not have all the information needed to do
+// unwind. So we just grab, up to, 32k of stack.
+bool LinuxDumper::GetStackInfo(const void** stack, size_t* stack_len,
+                               uintptr_t int_stack_pointer) {
+  // Move the stack pointer to the bottom of the page that it's in.
+  const uintptr_t page_size = getpagesize();
+
+  uint8_t* const stack_pointer =
+      reinterpret_cast<uint8_t*>(int_stack_pointer & ~(page_size - 1));
+
+  // The number of bytes of stack which we try to capture.
+  static const ptrdiff_t kStackToCapture = 32 * 1024;
+
+  const MappingInfo* mapping = FindMapping(stack_pointer);
+  if (!mapping)
+    return false;
+  const ptrdiff_t offset = stack_pointer -
+      reinterpret_cast<uint8_t*>(mapping->start_addr);
+  const ptrdiff_t distance_to_end =
+      static_cast<ptrdiff_t>(mapping->size) - offset;
+  *stack_len = distance_to_end > kStackToCapture ?
+      kStackToCapture : distance_to_end;
+  *stack = stack_pointer;
+  return true;
+}
+
+void LinuxDumper::SanitizeStackCopy(uint8_t* stack_copy, size_t stack_len,
+                                    uintptr_t stack_pointer,
+                                    uintptr_t sp_offset) {
+  // We optimize the search for containing mappings in three ways:
+  // 1) We expect that pointers into the stack mapping will be common, so
+  //    we cache that address range.
+  // 2) The last referenced mapping is a reasonable predictor for the next
+  //    referenced mapping, so we test that first.
+  // 3) We precompute a bitfield based upon bits 32:32-n of the start and
+  //    stop addresses, and use that to short circuit any values that can
+  //    not be pointers. (n=11)
+  const uintptr_t defaced =
+#if defined(__LP64__)
+      0x0defaced0defaced;
+#else
+      0x0defaced;
+#endif
+  // the bitfield length is 2^test_bits long.
+  const unsigned int test_bits = 11;
+  // byte length of the corresponding array.
+  const unsigned int array_size = 1 << (test_bits - 3);
+  const unsigned int array_mask = array_size - 1;
+  // The amount to right shift pointers by. This captures the top bits
+  // on 32 bit architectures. On 64 bit architectures this would be
+  // uninformative so we take the same range of bits.
+  const unsigned int shift = 32 - 11;
+  const MappingInfo* last_hit_mapping = nullptr;
+  const MappingInfo* hit_mapping = nullptr;
+  const MappingInfo* stack_mapping = FindMappingNoBias(stack_pointer);
+  // The magnitude below which integers are considered to be to be
+  // 'small', and not constitute a PII risk. These are included to
+  // avoid eliding useful register values.
+  const ssize_t small_int_magnitude = 4096;
+
+  char could_hit_mapping[array_size];
+  my_memset(could_hit_mapping, 0, array_size);
+
+  // Initialize the bitfield such that if the (pointer >> shift)'th
+  // bit, modulo the bitfield size, is not set then there does not
+  // exist a mapping in mappings_ that would contain that pointer.
+  for (size_t i = 0; i < mappings_.size(); ++i) {
+    if (!mappings_[i]->exec) continue;
+    // For each mapping, work out the (unmodulo'ed) range of bits to
+    // set.
+    uintptr_t start = mappings_[i]->start_addr;
+    uintptr_t end = start + mappings_[i]->size;
+    start >>= shift;
+    end >>= shift;
+    for (size_t bit = start; bit <= end; ++bit) {
+      // Set each bit in the range, applying the modulus.
+      could_hit_mapping[(bit >> 3) & array_mask] |= 1 << (bit & 7);
+    }
+  }
+
+  // Zero memory that is below the current stack pointer.
+  const uintptr_t offset =
+      (sp_offset + sizeof(uintptr_t) - 1) & ~(sizeof(uintptr_t) - 1);
+  if (offset) {
+    my_memset(stack_copy, 0, offset);
+  }
+
+  // Apply sanitization to each complete pointer-aligned word in the
+  // stack.
+  uint8_t* sp;
+  for (sp = stack_copy + offset;
+       sp <= stack_copy + stack_len - sizeof(uintptr_t);
+       sp += sizeof(uintptr_t)) {
+    uintptr_t addr;
+    my_memcpy(&addr, sp, sizeof(uintptr_t));
+    if (static_cast<intptr_t>(addr) <= small_int_magnitude &&
+        static_cast<intptr_t>(addr) >= -small_int_magnitude) {
+      continue;
+    }
+    if (stack_mapping && MappingContainsAddress(*stack_mapping, addr)) {
+      continue;
+    }
+    if (last_hit_mapping && MappingContainsAddress(*last_hit_mapping, addr)) {
+      continue;
+    }
+    uintptr_t test = addr >> shift;
+    if (could_hit_mapping[(test >> 3) & array_mask] & (1 << (test & 7)) &&
+        (hit_mapping = FindMappingNoBias(addr)) != nullptr &&
+        hit_mapping->exec) {
+      last_hit_mapping = hit_mapping;
+      continue;
+    }
+    my_memcpy(sp, &defaced, sizeof(uintptr_t));
+  }
+  // Zero any partial word at the top of the stack, if alignment is
+  // such that that is required.
+  if (sp < stack_copy + stack_len) {
+    my_memset(sp, 0, stack_copy + stack_len - sp);
+  }
+}
+
+bool LinuxDumper::StackHasPointerToMapping(const uint8_t* stack_copy,
+                                           size_t stack_len,
+                                           uintptr_t sp_offset,
+                                           const MappingInfo& mapping) {
+  // Loop over all stack words that would have been on the stack in
+  // the target process (i.e. are word aligned, and at addresses >=
+  // the stack pointer).  Regardless of the alignment of |stack_copy|,
+  // the memory starting at |stack_copy| + |offset| represents an
+  // aligned word in the target process.
+  const uintptr_t low_addr = mapping.system_mapping_info.start_addr;
+  const uintptr_t high_addr = mapping.system_mapping_info.end_addr;
+  const uintptr_t offset =
+      (sp_offset + sizeof(uintptr_t) - 1) & ~(sizeof(uintptr_t) - 1);
+
+  for (const uint8_t* sp = stack_copy + offset;
+       sp <= stack_copy + stack_len - sizeof(uintptr_t);
+       sp += sizeof(uintptr_t)) {
+    uintptr_t addr;
+    my_memcpy(&addr, sp, sizeof(uintptr_t));
+    if (low_addr <= addr && addr <= high_addr)
+      return true;
+  }
+  return false;
+}
+
+// Find the mapping which the given memory address falls in.
+const MappingInfo* LinuxDumper::FindMapping(const void* address) const {
+  const uintptr_t addr = (uintptr_t) address;
+
+  for (size_t i = 0; i < mappings_.size(); ++i) {
+    const uintptr_t start = static_cast<uintptr_t>(mappings_[i]->start_addr);
+    if (addr >= start && addr - start < mappings_[i]->size)
+      return mappings_[i];
+  }
+
+  return NULL;
+}
+
+// Find the mapping which the given memory address falls in. Uses the
+// unadjusted mapping address range from the kernel, rather than the
+// biased range.
+const MappingInfo* LinuxDumper::FindMappingNoBias(uintptr_t address) const {
+  for (size_t i = 0; i < mappings_.size(); ++i) {
+    if (address >= mappings_[i]->system_mapping_info.start_addr &&
+        address < mappings_[i]->system_mapping_info.end_addr) {
+      return mappings_[i];
+    }
+  }
+  return NULL;
+}
+
+bool LinuxDumper::HandleDeletedFileInMapping(char* path) const {
+  static const size_t kDeletedSuffixLen = sizeof(kDeletedSuffix) - 1;
+
+  // Check for ' (deleted)' in |path|.
+  // |path| has to be at least as long as "/x (deleted)".
+  const size_t path_len = my_strlen(path);
+  if (path_len < kDeletedSuffixLen + 2)
+    return false;
+  if (my_strncmp(path + path_len - kDeletedSuffixLen, kDeletedSuffix,
+                 kDeletedSuffixLen) != 0) {
+    return false;
+  }
+
+  // Check |path| against the /proc/pid/exe 'symlink'.
+  char exe_link[NAME_MAX];
+  if (!BuildProcPath(exe_link, pid_, "exe"))
+    return false;
+  MappingInfo new_mapping = {0};
+  if (!SafeReadLink(exe_link, new_mapping.name))
+    return false;
+  char new_path[PATH_MAX];
+  if (!GetMappingAbsolutePath(new_mapping, new_path))
+    return false;
+  if (my_strcmp(path, new_path) != 0)
+    return false;
+
+  // Check to see if someone actually named their executable 'foo (deleted)'.
+  struct kernel_stat exe_stat;
+  struct kernel_stat new_path_stat;
+  if (sys_stat(exe_link, &exe_stat) == 0 &&
+      sys_stat(new_path, &new_path_stat) == 0 &&
+      exe_stat.st_dev == new_path_stat.st_dev &&
+      exe_stat.st_ino == new_path_stat.st_ino) {
+    return false;
+  }
+
+  my_memcpy(path, exe_link, NAME_MAX);
+  return true;
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper.h
new file mode 100644
index 0000000000..7155524ffc
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper.h
@@ -0,0 +1,333 @@
+// Copyright (c) 2010, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_dumper.h: Define the google_breakpad::LinuxDumper class, which
+// is a base class for extracting information of a crashed process. It
+// was originally a complete implementation using the ptrace API, but
+// has been refactored to allow derived implementations supporting both
+// ptrace and core dump. A portion of the original implementation is now
+// in google_breakpad::LinuxPtraceDumper (see linux_ptrace_dumper.h for
+// details).
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_DUMPER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_DUMPER_H_
+
+#include <assert.h>
+#include <elf.h>
+#if defined(__ANDROID__)
+#include <link.h>
+#endif
+#include <linux/limits.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/user.h>
+
+#include <vector>
+
+#include "linux/dump_writer_common/mapping_info.h"
+#include "linux/dump_writer_common/thread_info.h"
+#include "common/linux/file_id.h"
+#include "common/memory_allocator.h"
+#include "google_breakpad/common/minidump_format.h"
+
+namespace google_breakpad {
+
+// Typedef for our parsing of the auxv variables in /proc/pid/auxv.
+#if defined(__i386) || defined(__ARM_EABI__) || \
+ (defined(__mips__) && _MIPS_SIM == _ABIO32)
+typedef Elf32_auxv_t elf_aux_entry;
+#elif defined(__x86_64) || defined(__aarch64__) || \
+     (defined(__mips__) && _MIPS_SIM != _ABIO32)
+typedef Elf64_auxv_t elf_aux_entry;
+#endif
+
+typedef __typeof__(((elf_aux_entry*) 0)->a_un.a_val) elf_aux_val_t;
+
+// When we find the VDSO mapping in the process's address space, this
+// is the name we use for it when writing it to the minidump.
+// This should always be less than NAME_MAX!
+const char kLinuxGateLibraryName[] = "linux-gate.so";
+
+class LinuxDumper {
+ public:
+  // The |root_prefix| is prepended to mapping paths before opening them, which
+  // is useful if the crash originates from a chroot.
+  explicit LinuxDumper(pid_t pid, const char* root_prefix = "");
+
+  virtual ~LinuxDumper();
+
+  // Parse the data for |threads| and |mappings|.
+  virtual bool Init();
+
+  // Take any actions that could not be taken in Init(). LateInit() is
+  // called after all other caller's initialization is complete, and in
+  // particular after it has called ThreadsSuspend(), so that ptrace is
+  // available.
+  virtual bool LateInit();
+
+  // Return true if the dumper performs a post-mortem dump.
+  virtual bool IsPostMortem() const = 0;
+
+  // Suspend/resume all threads in the given process.
+  virtual bool ThreadsSuspend() = 0;
+  virtual bool ThreadsResume() = 0;
+
+  // Read information about the |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadInfoByIndex(size_t index, ThreadInfo* info) = 0;
+
+  // Read the name ofthe |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadNameByIndex(size_t index, char* name, size_t size) = 0;
+
+  size_t GetMainThreadIndex() const {
+    for (size_t i = 0; i < threads_.size(); ++i) {
+      if (threads_[i] == pid_) return i;
+    }
+    return -1u;
+  }
+
+  // These are only valid after a call to |Init|.
+  const wasteful_vector<pid_t> &threads() { return threads_; }
+  const wasteful_vector<MappingInfo*> &mappings() { return mappings_; }
+  const MappingInfo* FindMapping(const void* address) const;
+  // Find the mapping which the given memory address falls in. Unlike
+  // FindMapping, this method uses the unadjusted mapping address
+  // ranges from the kernel, rather than the ranges that have had the
+  // load bias applied.
+  const MappingInfo* FindMappingNoBias(uintptr_t address) const;
+  const wasteful_vector<elf_aux_val_t>& auxv() { return auxv_; }
+
+  // Find a block of memory to take as the stack given the top of stack pointer.
+  //   stack: (output) the lowest address in the memory area
+  //   stack_len: (output) the length of the memory area
+  //   stack_top: the current top of the stack
+  bool GetStackInfo(const void** stack, size_t* stack_len, uintptr_t stack_top);
+
+  // Sanitize a copy of the stack by overwriting words that are not
+  // pointers with a sentinel (0x0defaced).
+  //   stack_copy: a copy of the stack to sanitize. |stack_copy| might
+  //               not be word aligned, but it represents word aligned
+  //               data copied from another location.
+  //   stack_len: the length of the allocation pointed to by |stack_copy|.
+  //   stack_pointer: the address of the stack pointer (used to locate
+  //                  the stack mapping, as an optimization).
+  //   sp_offset: the offset relative to stack_copy that reflects the
+  //              current value of the stack pointer.
+  void SanitizeStackCopy(uint8_t* stack_copy, size_t stack_len,
+                         uintptr_t stack_pointer, uintptr_t sp_offset);
+
+  // Test whether |stack_copy| contains a pointer-aligned word that
+  // could be an address within a given mapping.
+  //   stack_copy: a copy of the stack to check. |stack_copy| might
+  //               not be word aligned, but it represents word aligned
+  //               data copied from another location.
+  //   stack_len: the length of the allocation pointed to by |stack_copy|.
+  //   sp_offset: the offset relative to stack_copy that reflects the
+  //              current value of the stack pointer.
+  //   mapping: the mapping against which to test stack words.
+  bool StackHasPointerToMapping(const uint8_t* stack_copy, size_t stack_len,
+                                uintptr_t sp_offset,
+                                const MappingInfo& mapping);
+
+  PageAllocator* allocator() { return &allocator_; }
+
+  // Copy content of |length| bytes from a given process |child|,
+  // starting from |src|, into |dest|. Returns true on success.
+  virtual bool CopyFromProcess(void* dest, pid_t child, const void* src,
+                               size_t length) = 0;
+
+  // Builds a proc path for a certain pid for a node (/proc/<pid>/<node>).
+  // |path| is a character array of at least NAME_MAX bytes to return the
+  // result.|node| is the final node without any slashes. Returns true on
+  // success.
+  virtual bool BuildProcPath(char* path, pid_t pid, const char* node) const = 0;
+
+  // Generate a File ID from the .text section of a mapped entry.
+  // If not a member, mapping_id is ignored. This method can also manipulate the
+  // |mapping|.name to truncate "(deleted)" from the file name if necessary.
+  bool ElfFileIdentifierForMapping(const MappingInfo& mapping,
+                                   bool member,
+                                   unsigned int mapping_id,
+                                   wasteful_vector<uint8_t>& identifier);
+
+  void SetCrashInfoFromSigInfo(const siginfo_t& siginfo);
+
+  uintptr_t crash_address() const { return crash_address_; }
+  void set_crash_address(uintptr_t crash_address) {
+    crash_address_ = crash_address;
+  }
+
+  int crash_signal() const { return crash_signal_; }
+  void set_crash_signal(int crash_signal) { crash_signal_ = crash_signal; }
+  const char* GetCrashSignalString() const;
+
+  void set_crash_signal_code(int code) { crash_signal_code_ = code; }
+  int crash_signal_code() const { return crash_signal_code_; }
+
+  void set_crash_exception_info(const std::vector<uint64_t>& exception_info) {
+    assert(exception_info.size() <= MD_EXCEPTION_MAXIMUM_PARAMETERS);
+    crash_exception_info_ = exception_info;
+  }
+  const std::vector<uint64_t>& crash_exception_info() const {
+    return crash_exception_info_;
+  }
+
+  pid_t pid() const { return pid_; }
+  pid_t crash_thread() const { return crash_thread_; }
+  void set_crash_thread(pid_t crash_thread) { crash_thread_ = crash_thread; }
+
+  // Concatenates the |root_prefix_| and |mapping| path. Writes into |path| and
+  // returns true unless the string is too long.
+  bool GetMappingAbsolutePath(const MappingInfo& mapping,
+                              char path[PATH_MAX]) const;
+
+  // Extracts the effective path and file name of from |mapping|. In most cases
+  // the effective name/path are just the mapping's path and basename. In some
+  // other cases, however, a library can be mapped from an archive (e.g., when
+  // loading .so libs from an apk on Android) and this method is able to
+  // reconstruct the original file name.
+  void GetMappingEffectiveNameAndPath(const MappingInfo& mapping,
+                                      char* file_path,
+                                      size_t file_path_size,
+                                      char* file_name,
+                                      size_t file_name_size);
+
+ protected:
+  bool ReadAuxv();
+
+  virtual bool EnumerateMappings();
+
+  virtual bool EnumerateThreads() = 0;
+
+  // For the case where a running program has been deleted, it'll show up in
+  // /proc/pid/maps as "/path/to/program (deleted)". If this is the case, then
+  // see if '/path/to/program (deleted)' matches /proc/pid/exe and return
+  // /proc/pid/exe in |path| so ELF identifier generation works correctly. This
+  // also checks to see if '/path/to/program (deleted)' exists, so it does not
+  // get fooled by a poorly named binary.
+  // For programs that don't end with ' (deleted)', this is a no-op.
+  // This assumes |path| is a buffer with length NAME_MAX.
+  // Returns true if |path| is modified.
+  bool HandleDeletedFileInMapping(char* path) const;
+
+   // ID of the crashed process.
+  const pid_t pid_;
+
+  // Path of the root directory to which mapping paths are relative.
+  const char* const root_prefix_;
+
+  // Virtual address at which the process crashed.
+  uintptr_t crash_address_;
+
+  // Signal that terminated the crashed process.
+  int crash_signal_;
+
+  // The code associated with |crash_signal_|.
+  int crash_signal_code_;
+
+  // The additional fields associated with |crash_signal_|.
+  std::vector<uint64_t> crash_exception_info_;
+
+  // ID of the crashed thread.
+  pid_t crash_thread_;
+
+  mutable PageAllocator allocator_;
+
+  // IDs of all the threads.
+  wasteful_vector<pid_t> threads_;
+
+  // Info from /proc/<pid>/maps.
+  wasteful_vector<MappingInfo*> mappings_;
+
+  // Info from /proc/<pid>/auxv
+  wasteful_vector<elf_aux_val_t> auxv_;
+
+private:
+  bool IsIPCSharedMemorySegment(const char* name);
+
+#if defined(__ANDROID__)
+  // Android M and later support packed ELF relocations in shared libraries.
+  // Packing relocations changes the vaddr of the LOAD segments, such that
+  // the effective load bias is no longer the same as the start address of
+  // the memory mapping containing the executable parts of the library. The
+  // packing is applied to the stripped library run on the target, but not to
+  // any other library, and in particular not to the library used to generate
+  // breakpad symbols. As a result, we need to adjust the |start_addr| for
+  // any mapping that results from a shared library that contains Android
+  // packed relocations, so that it properly represents the effective library
+  // load bias. The following functions support this adjustment.
+
+  // Check that a given mapping at |start_addr| is for an ELF shared library.
+  // If it is, place the ELF header in |ehdr| and return true.
+  // The first LOAD segment in an ELF shared library has offset zero, so the
+  // ELF file header is at the start of this map entry, and in already mapped
+  // memory.
+  bool GetLoadedElfHeader(uintptr_t start_addr, ElfW(Ehdr)* ehdr);
+
+  // For the ELF file mapped at |start_addr|, iterate ELF program headers to
+  // find the min vaddr of all program header LOAD segments, the vaddr for
+  // the DYNAMIC segment, and a count of DYNAMIC entries. Return values in
+  // |min_vaddr_ptr|, |dyn_vaddr_ptr|, and |dyn_count_ptr|.
+  // The program header table is also in already mapped memory.
+  void ParseLoadedElfProgramHeaders(ElfW(Ehdr)* ehdr,
+                                    uintptr_t start_addr,
+                                    uintptr_t* min_vaddr_ptr,
+                                    uintptr_t* dyn_vaddr_ptr,
+                                    size_t* dyn_count_ptr);
+
+  // Search the DYNAMIC tags for the ELF file with the given |load_bias|, and
+  // return true if the tags indicate that the file contains Android packed
+  // relocations. Dynamic tags are found at |dyn_vaddr| past the |load_bias|.
+  bool HasAndroidPackedRelocations(uintptr_t load_bias,
+                                   uintptr_t dyn_vaddr,
+                                   size_t dyn_count);
+
+  // If the ELF file mapped at |start_addr| contained Android packed
+  // relocations, return the load bias that the system linker (or Chromium
+  // crazy linker) will have used. If the file did not contain Android
+  // packed relocations, returns |start_addr|, indicating that no adjustment
+  // is necessary.
+  // The effective load bias is |start_addr| adjusted downwards by the
+  // min vaddr in the library LOAD segments.
+  uintptr_t GetEffectiveLoadBias(ElfW(Ehdr)* ehdr, uintptr_t start_addr);
+
+  // Called from LateInit(). Iterates |mappings_| and rewrites the |start_addr|
+  // field of any that represent ELF shared libraries with Android packed
+  // relocations, so that |start_addr| is the load bias that the system linker
+  // (or Chromium crazy linker) used. This value matches the addresses produced
+  // when the non-relocation-packed library is used for breakpad symbol
+  // generation.
+  void LatePostprocessMappings();
+#endif  // __ANDROID__
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_LINUX_DUMPER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper_unittest_helper.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper_unittest_helper.cc
new file mode 100644
index 0000000000..3ad48e5015
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_dumper_unittest_helper.cc
@@ -0,0 +1,95 @@
+// Copyright (c) 2010, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Helper program for the linux_dumper class, which creates a bunch of
+// threads. The first word of each thread's stack is set to the thread
+// id.
+
+#include <pthread.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "common/scoped_ptr.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+#if defined(__ARM_EABI__)
+#define TID_PTR_REGISTER "r3"
+#elif defined(__aarch64__)
+#define TID_PTR_REGISTER "x3"
+#elif defined(__i386)
+#define TID_PTR_REGISTER "ecx"
+#elif defined(__x86_64)
+#define TID_PTR_REGISTER "rcx"
+#elif defined(__mips__)
+#define TID_PTR_REGISTER "$1"
+#else
+#error This test has not been ported to this platform.
+#endif
+
+void *thread_function(void *data) {
+  int pipefd = *static_cast<int *>(data);
+  volatile pid_t* thread_id = new pid_t;
+  *thread_id = syscall(__NR_gettid);
+  // Signal parent that a thread has started.
+  uint8_t byte = 1;
+  if (write(pipefd, &byte, sizeof(byte)) != sizeof(byte)) {
+    perror("ERROR: parent notification failed");
+    return NULL;
+  }
+  register volatile pid_t *thread_id_ptr asm(TID_PTR_REGISTER) = thread_id;
+  while (true)
+    asm volatile ("" : : "r" (thread_id_ptr));
+  return NULL;
+}
+
+int main(int argc, char *argv[]) {
+  if (argc < 3) {
+    fprintf(stderr,
+            "usage: linux_dumper_unittest_helper <pipe fd> <# of threads>\n");
+    return 1;
+  }
+  int pipefd = atoi(argv[1]);
+  int num_threads = atoi(argv[2]);
+  if (num_threads < 1) {
+    fprintf(stderr, "ERROR: number of threads is 0");
+    return 1;
+  }
+  google_breakpad::scoped_array<pthread_t> threads(new pthread_t[num_threads]);
+  pthread_attr_t thread_attributes;
+  pthread_attr_init(&thread_attributes);
+  pthread_attr_setdetachstate(&thread_attributes, PTHREAD_CREATE_DETACHED);
+  for (int i = 1; i < num_threads; i++) {
+    pthread_create(&threads[i], &thread_attributes, &thread_function, &pipefd);
+  }
+  thread_function(&pipefd);
+  return 0;
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper.cc
new file mode 100644
index 0000000000..6ed70eeb61
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper.cc
@@ -0,0 +1,403 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_ptrace_dumper.cc: Implement google_breakpad::LinuxPtraceDumper.
+// See linux_ptrace_dumper.h for detals.
+// This class was originally splitted from google_breakpad::LinuxDumper.
+
+// This code deals with the mechanics of getting information about a crashed
+// process. Since this code may run in a compromised address space, the same
+// rules apply as detailed at the top of minidump_writer.h: no libc calls and
+// use the alternative allocator.
+
+#include "linux/minidump_writer/linux_ptrace_dumper.h"
+
+#include <asm/ptrace.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ptrace.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+
+#if defined(__i386)
+#include <cpuid.h>
+#endif
+
+#include "linux/minidump_writer/directory_reader.h"
+#include "linux/minidump_writer/line_reader.h"
+#include "common/linux/linux_libc_support.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+// Suspends a thread by attaching to it.
+static bool SuspendThread(pid_t pid) {
+  // This may fail if the thread has just died or debugged.
+  errno = 0;
+  if (sys_ptrace(PTRACE_ATTACH, pid, NULL, NULL) != 0 &&
+      errno != 0) {
+    return false;
+  }
+  while (sys_waitpid(pid, NULL, __WALL) < 0) {
+    if (errno != EINTR) {
+      sys_ptrace(PTRACE_DETACH, pid, NULL, NULL);
+      return false;
+    }
+  }
+#if defined(__i386) || defined(__x86_64)
+  // On x86, the stack pointer is NULL or -1, when executing trusted code in
+  // the seccomp sandbox. Not only does this cause difficulties down the line
+  // when trying to dump the thread's stack, it also results in the minidumps
+  // containing information about the trusted threads. This information is
+  // generally completely meaningless and just pollutes the minidumps.
+  // We thus test the stack pointer and exclude any threads that are part of
+  // the seccomp sandbox's trusted code.
+  user_regs_struct regs;
+  if (sys_ptrace(PTRACE_GETREGS, pid, NULL, &regs) == -1 ||
+#if defined(__i386)
+      !regs.esp
+#elif defined(__x86_64)
+      !regs.rsp
+#endif
+      ) {
+    sys_ptrace(PTRACE_DETACH, pid, NULL, NULL);
+    return false;
+  }
+#endif
+  return true;
+}
+
+// Resumes a thread by detaching from it.
+static bool ResumeThread(pid_t pid) {
+  return sys_ptrace(PTRACE_DETACH, pid, NULL, NULL) >= 0;
+}
+
+namespace google_breakpad {
+
+LinuxPtraceDumper::LinuxPtraceDumper(pid_t pid)
+    : LinuxDumper(pid),
+      threads_suspended_(false) {
+}
+
+bool LinuxPtraceDumper::BuildProcPath(char* path, pid_t pid,
+                                      const char* node) const {
+  if (!path || !node || pid <= 0)
+    return false;
+
+  size_t node_len = my_strlen(node);
+  if (node_len == 0)
+    return false;
+
+  const unsigned pid_len = my_uint_len(pid);
+  const size_t total_length = 6 + pid_len + 1 + node_len;
+  if (total_length >= NAME_MAX)
+    return false;
+
+  my_memcpy(path, "/proc/", 6);
+  my_uitos(path + 6, pid, pid_len);
+  path[6 + pid_len] = '/';
+  my_memcpy(path + 6 + pid_len + 1, node, node_len);
+  path[total_length] = '\0';
+  return true;
+}
+
+bool LinuxPtraceDumper::CopyFromProcess(void* dest, pid_t child,
+                                        const void* src, size_t length) {
+  unsigned long tmp = 55;
+  size_t done = 0;
+  static const size_t word_size = sizeof(tmp);
+  uint8_t* const local = (uint8_t*) dest;
+  uint8_t* const remote = (uint8_t*) src;
+
+  while (done < length) {
+    const size_t l = (length - done > word_size) ? word_size : (length - done);
+    if (sys_ptrace(PTRACE_PEEKDATA, child, remote + done, &tmp) == -1) {
+      tmp = 0;
+    }
+    my_memcpy(local + done, &tmp, l);
+    done += l;
+  }
+  return true;
+}
+
+bool LinuxPtraceDumper::ReadRegisterSet(ThreadInfo* info, pid_t tid)
+{
+#ifdef PTRACE_GETREGSET
+  struct iovec io;
+  info->GetGeneralPurposeRegisters(&io.iov_base, &io.iov_len);
+  if (sys_ptrace(PTRACE_GETREGSET, tid, (void*)NT_PRSTATUS, (void*)&io) == -1) {
+    return false;
+  }
+
+  info->GetFloatingPointRegisters(&io.iov_base, &io.iov_len);
+  if (sys_ptrace(PTRACE_GETREGSET, tid, (void*)NT_FPREGSET, (void*)&io) == -1) {
+    return false;
+  }
+  return true;
+#else
+  return false;
+#endif
+}
+
+bool LinuxPtraceDumper::ReadRegisters(ThreadInfo* info, pid_t tid) {
+#ifdef PTRACE_GETREGS
+  void* gp_addr;
+  info->GetGeneralPurposeRegisters(&gp_addr, NULL);
+  if (sys_ptrace(PTRACE_GETREGS, tid, NULL, gp_addr) == -1) {
+    return false;
+  }
+
+#if !(defined(__ANDROID__) && defined(__ARM_EABI__))
+  // When running an arm build on an arm64 device, attempting to get the
+  // floating point registers fails. On Android, the floating point registers
+  // aren't written to the cpu context anyway, so just don't get them here.
+  // See http://crbug.com/508324
+  void* fp_addr;
+  info->GetFloatingPointRegisters(&fp_addr, NULL);
+  if (sys_ptrace(PTRACE_GETFPREGS, tid, NULL, fp_addr) == -1) {
+    return false;
+  }
+#endif  // !(defined(__ANDROID__) && defined(__ARM_EABI__))
+  return true;
+#else  // PTRACE_GETREGS
+  return false;
+#endif
+}
+
+// Read thread info from /proc/$pid/status.
+// Fill out the |tgid|, |ppid| and |pid| members of |info|. If unavailable,
+// these members are set to -1. Returns true iff all three members are
+// available.
+bool LinuxPtraceDumper::GetThreadInfoByIndex(size_t index, ThreadInfo* info) {
+  if (index >= threads_.size())
+    return false;
+
+  pid_t tid = threads_[index];
+
+  assert(info != NULL);
+  char status_path[NAME_MAX];
+  if (!BuildProcPath(status_path, tid, "status"))
+    return false;
+
+  const int fd = sys_open(status_path, O_RDONLY, 0);
+  if (fd < 0)
+    return false;
+
+  LineReader* const line_reader = new(allocator_) LineReader(fd);
+  const char* line;
+  unsigned line_len;
+
+  info->ppid = info->tgid = -1;
+
+  while (line_reader->GetNextLine(&line, &line_len)) {
+    if (my_strncmp("Tgid:\t", line, 6) == 0) {
+      my_strtoui(&info->tgid, line + 6);
+    } else if (my_strncmp("PPid:\t", line, 6) == 0) {
+      my_strtoui(&info->ppid, line + 6);
+    }
+
+    line_reader->PopLine(line_len);
+  }
+  sys_close(fd);
+
+  if (info->ppid == -1 || info->tgid == -1)
+    return false;
+
+  if (!ReadRegisterSet(info, tid)) {
+    if (!ReadRegisters(info, tid)) {
+      return false;
+    }
+  }
+
+#if defined(__i386)
+#if !defined(bit_FXSAVE)  // e.g. Clang
+#define bit_FXSAVE bit_FXSR
+#endif
+  // Detect if the CPU supports the FXSAVE/FXRSTOR instructions
+  int eax, ebx, ecx, edx;
+  __cpuid(1, eax, ebx, ecx, edx);
+  if (edx & bit_FXSAVE) {
+    if (sys_ptrace(PTRACE_GETFPXREGS, tid, NULL, &info->fpxregs) == -1) {
+      return false;
+    }
+  } else {
+    memset(&info->fpxregs, 0, sizeof(info->fpxregs));
+  }
+#endif  // defined(__i386)
+
+#if defined(__i386) || defined(__x86_64)
+  for (unsigned i = 0; i < ThreadInfo::kNumDebugRegisters; ++i) {
+    if (sys_ptrace(
+        PTRACE_PEEKUSER, tid,
+        reinterpret_cast<void*> (offsetof(struct user,
+                                          u_debugreg[0]) + i *
+                                 sizeof(debugreg_t)),
+        &info->dregs[i]) == -1) {
+      return false;
+    }
+  }
+#endif
+
+#if defined(__mips__)
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(PC), &info->mcontext.pc);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_BASE), &info->mcontext.hi1);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_BASE + 1), &info->mcontext.lo1);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_BASE + 2), &info->mcontext.hi2);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_BASE + 3), &info->mcontext.lo2);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_BASE + 4), &info->mcontext.hi3);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_BASE + 5), &info->mcontext.lo3);
+  sys_ptrace(PTRACE_PEEKUSER, tid,
+             reinterpret_cast<void*>(DSP_CONTROL), &info->mcontext.dsp);
+#endif
+
+  const uint8_t* stack_pointer;
+#if defined(__i386)
+  my_memcpy(&stack_pointer, &info->regs.esp, sizeof(info->regs.esp));
+#elif defined(__x86_64)
+  my_memcpy(&stack_pointer, &info->regs.rsp, sizeof(info->regs.rsp));
+#elif defined(__ARM_EABI__)
+  my_memcpy(&stack_pointer, &info->regs.ARM_sp, sizeof(info->regs.ARM_sp));
+#elif defined(__aarch64__)
+  my_memcpy(&stack_pointer, &info->regs.sp, sizeof(info->regs.sp));
+#elif defined(__mips__)
+  stack_pointer =
+      reinterpret_cast<uint8_t*>(info->mcontext.gregs[MD_CONTEXT_MIPS_REG_SP]);
+#else
+#error "This code hasn't been ported to your platform yet."
+#endif
+  info->stack_pointer = reinterpret_cast<uintptr_t>(stack_pointer);
+
+  return true;
+}
+
+bool LinuxPtraceDumper::GetThreadNameByIndex(size_t index, char* name,
+                                             size_t size) {
+  if (index >= threads_.size())
+    return false;
+
+  pid_t tid = threads_[index];
+
+  assert(name != NULL);
+  char path[NAME_MAX];
+
+  // Read the thread name (aka comm entry in /proc)
+  if (!BuildProcPath(path, tid, "comm"))
+    return false;
+
+  const int fd = sys_open(path, O_RDONLY, 0);
+  if (fd < 0)
+    return false;
+
+  const int len = sys_read(fd, name, size);
+  if (len > 0)
+    name[len - 1] = '\0'; // Get rid of the newline
+
+  sys_close(fd);
+
+  return len > 0;
+}
+
+bool LinuxPtraceDumper::IsPostMortem() const {
+  return false;
+}
+
+bool LinuxPtraceDumper::ThreadsSuspend() {
+  if (threads_suspended_)
+    return true;
+  for (size_t i = 0; i < threads_.size(); ++i) {
+    if (!SuspendThread(threads_[i])) {
+      // If the thread either disappeared before we could attach to it, or if
+      // it was part of the seccomp sandbox's trusted code, it is OK to
+      // silently drop it from the minidump.
+      if (i < threads_.size() - 1) {
+        my_memmove(&threads_[i], &threads_[i + 1],
+                   (threads_.size() - i - 1) * sizeof(threads_[i]));
+      }
+      threads_.resize(threads_.size() - 1);
+      --i;
+    }
+  }
+  threads_suspended_ = true;
+  return !threads_.empty();
+}
+
+bool LinuxPtraceDumper::ThreadsResume() {
+  if (!threads_suspended_)
+    return false;
+  bool good = true;
+  for (size_t i = 0; i < threads_.size(); ++i)
+    good &= ResumeThread(threads_[i]);
+  threads_suspended_ = false;
+  return good;
+}
+
+// Parse /proc/$pid/task to list all the threads of the process identified by
+// pid.
+bool LinuxPtraceDumper::EnumerateThreads() {
+  char task_path[NAME_MAX];
+  if (!BuildProcPath(task_path, pid_, "task"))
+    return false;
+
+  const int fd = sys_open(task_path, O_RDONLY | O_DIRECTORY, 0);
+  if (fd < 0)
+    return false;
+  DirectoryReader* dir_reader = new(allocator_) DirectoryReader(fd);
+
+  // The directory may contain duplicate entries which we filter by assuming
+  // that they are consecutive.
+  int last_tid = -1;
+  const char* dent_name;
+  while (dir_reader->GetNextEntry(&dent_name)) {
+    if (my_strcmp(dent_name, ".") &&
+        my_strcmp(dent_name, "..")) {
+      int tid = 0;
+      if (my_strtoui(&tid, dent_name) &&
+          last_tid != tid) {
+        last_tid = tid;
+        threads_.push_back(tid);
+      }
+    }
+    dir_reader->PopEntry();
+  }
+
+  sys_close(fd);
+  return true;
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper.h
new file mode 100644
index 0000000000..576098c349
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper.h
@@ -0,0 +1,106 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_ptrace_dumper.h: Define the google_breakpad::LinuxPtraceDumper
+// class, which is derived from google_breakpad::LinuxDumper to extract
+// information from a crashed process via ptrace.
+// This class was originally splitted from google_breakpad::LinuxDumper.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_PTRACE_DUMPER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_PTRACE_DUMPER_H_
+
+#include "linux/minidump_writer/linux_dumper.h"
+
+namespace google_breakpad {
+
+class LinuxPtraceDumper : public LinuxDumper {
+ public:
+  // Constructs a dumper for extracting information of a given process
+  // with a process ID of |pid|.
+  explicit LinuxPtraceDumper(pid_t pid);
+
+  // Implements LinuxDumper::BuildProcPath().
+  // Builds a proc path for a certain pid for a node (/proc/<pid>/<node>).
+  // |path| is a character array of at least NAME_MAX bytes to return the
+  // result. |node| is the final node without any slashes. Returns true on
+  // success.
+  virtual bool BuildProcPath(char* path, pid_t pid, const char* node) const;
+
+  // Implements LinuxDumper::CopyFromProcess().
+  // Copies content of |length| bytes from a given process |child|,
+  // starting from |src|, into |dest|. This method uses ptrace to extract
+  // the content from the target process. Always returns true.
+  virtual bool CopyFromProcess(void* dest, pid_t child, const void* src,
+                               size_t length);
+
+  // Implements LinuxDumper::GetThreadInfoByIndex().
+  // Reads information about the |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadInfoByIndex(size_t index, ThreadInfo* info);
+
+  // Implements LinuxDumper::GetThreadNameByIndex().
+  // Reads the name of the |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadNameByIndex(size_t index, char* name, size_t size);
+
+  // Implements LinuxDumper::IsPostMortem().
+  // Always returns false to indicate this dumper performs a dump of
+  // a crashed process via ptrace.
+  virtual bool IsPostMortem() const;
+
+  // Implements LinuxDumper::ThreadsSuspend().
+  // Suspends all threads in the given process. Returns true on success.
+  virtual bool ThreadsSuspend();
+
+  // Implements LinuxDumper::ThreadsResume().
+  // Resumes all threads in the given process. Returns true on success.
+  virtual bool ThreadsResume();
+
+ protected:
+  // Implements LinuxDumper::EnumerateThreads().
+  // Enumerates all threads of the given process into |threads_|.
+  virtual bool EnumerateThreads();
+
+ private:
+  // Set to true if all threads of the crashed process are suspended.
+  bool threads_suspended_;
+
+  // Read the tracee's registers on kernel with PTRACE_GETREGSET support.
+  // Returns false if PTRACE_GETREGSET is not defined.
+  // Returns true on success.
+  bool ReadRegisterSet(ThreadInfo* info, pid_t tid);
+
+  // Read the tracee's registers on kernel with PTRACE_GETREGS support.
+  // Returns true on success.
+  bool ReadRegisters(ThreadInfo* info, pid_t tid);
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_LINUX_PTRACE_DUMPER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
new file mode 100644
index 0000000000..79d26a1e31
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
@@ -0,0 +1,580 @@
+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_ptrace_dumper_unittest.cc:
+// Unit tests for google_breakpad::LinuxPtraceDumper.
+//
+// This file was renamed from linux_dumper_unittest.cc and modified due
+// to LinuxDumper being splitted into two classes.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <poll.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <string>
+
+#include "breakpad_googletest_includes.h"
+#include "linux/minidump_writer/linux_ptrace_dumper.h"
+#include "linux/minidump_writer/minidump_writer_unittest_utils.h"
+#include "common/linux/eintr_wrapper.h"
+#include "common/linux/file_id.h"
+#include "common/linux/ignore_ret.h"
+#include "common/linux/safe_readlink.h"
+#include "common/memory_allocator.h"
+#include "common/using_std_string.h"
+
+#ifndef PR_SET_PTRACER
+#define PR_SET_PTRACER 0x59616d61
+#endif
+
+using namespace google_breakpad;
+
+namespace {
+
+pid_t SetupChildProcess(int number_of_threads) {
+  char kNumberOfThreadsArgument[2];
+  sprintf(kNumberOfThreadsArgument, "%d", number_of_threads);
+
+  int fds[2];
+  EXPECT_NE(-1, pipe(fds));
+
+  pid_t child_pid = fork();
+  if (child_pid == 0) {
+    // In child process.
+    close(fds[0]);
+
+    string helper_path(GetHelperBinary());
+    if (helper_path.empty()) {
+      fprintf(stderr, "Couldn't find helper binary\n");
+      _exit(1);
+    }
+
+    // Pass the pipe fd and the number of threads as arguments.
+    char pipe_fd_string[8];
+    sprintf(pipe_fd_string, "%d", fds[1]);
+    execl(helper_path.c_str(),
+          "linux_dumper_unittest_helper",
+          pipe_fd_string,
+          kNumberOfThreadsArgument,
+          NULL);
+    // Kill if we get here.
+    printf("Errno from exec: %d", errno);
+    std::string err_str = "Exec of  " + helper_path + " failed";
+    perror(err_str.c_str());
+    _exit(1);
+  }
+  close(fds[1]);
+
+  // Wait for all child threads to indicate that they have started
+  for (int threads = 0; threads < number_of_threads; threads++) {
+    struct pollfd pfd;
+    memset(&pfd, 0, sizeof(pfd));
+    pfd.fd = fds[0];
+    pfd.events = POLLIN | POLLERR;
+
+    const int r = HANDLE_EINTR(poll(&pfd, 1, 1000));
+    EXPECT_EQ(1, r);
+    EXPECT_TRUE(pfd.revents & POLLIN);
+    uint8_t junk;
+    EXPECT_EQ(read(fds[0], &junk, sizeof(junk)),
+              static_cast<ssize_t>(sizeof(junk)));
+  }
+  close(fds[0]);
+
+  // There is a race here because we may stop a child thread before
+  // it is actually running the busy loop. Empirically this sleep
+  // is sufficient to avoid the race.
+  usleep(100000);
+  return child_pid;
+}
+
+typedef wasteful_vector<uint8_t> id_vector;
+typedef testing::Test LinuxPtraceDumperTest;
+
+/* Fixture for running tests in a child process. */
+class LinuxPtraceDumperChildTest : public testing::Test {
+ protected:
+  virtual void SetUp() {
+    child_pid_ = fork();
+#ifndef __ANDROID__
+    prctl(PR_SET_PTRACER, child_pid_);
+#endif
+  }
+
+  /* Gtest is calling TestBody from this class, which sets up a child
+   * process in which the RealTestBody virtual member is called.
+   * As such, TestBody is not supposed to be overridden in derived classes.
+   */
+  virtual void TestBody() /* final */ {
+    if (child_pid_ == 0) {
+      // child process
+      RealTestBody();
+      _exit(HasFatalFailure() ? kFatalFailure :
+            (HasNonfatalFailure() ? kNonFatalFailure : 0));
+    }
+
+    ASSERT_TRUE(child_pid_ > 0);
+    int status;
+    waitpid(child_pid_, &status, 0);
+    if (WEXITSTATUS(status) == kFatalFailure) {
+      GTEST_FATAL_FAILURE_("Test failed in child process");
+    } else if (WEXITSTATUS(status) == kNonFatalFailure) {
+      GTEST_NONFATAL_FAILURE_("Test failed in child process");
+    }
+  }
+
+  /* Gtest defines TestBody functions through its macros, but classes
+   * derived from this one need to define RealTestBody instead.
+   * This is achieved by defining a TestBody macro further below.
+   */
+  virtual void RealTestBody() = 0;
+
+  id_vector make_vector() {
+    return id_vector(&allocator, kDefaultBuildIdSize);
+  }
+
+ private:
+  static const int kFatalFailure = 1;
+  static const int kNonFatalFailure = 2;
+
+  pid_t child_pid_;
+  PageAllocator allocator;
+};
+
+}  // namespace
+
+/* Replace TestBody declarations within TEST*() with RealTestBody
+ * declarations */
+#define TestBody RealTestBody
+
+TEST_F(LinuxPtraceDumperChildTest, Setup) {
+  LinuxPtraceDumper dumper(getppid());
+}
+
+TEST_F(LinuxPtraceDumperChildTest, FindMappings) {
+  LinuxPtraceDumper dumper(getppid());
+  ASSERT_TRUE(dumper.Init());
+
+  ASSERT_TRUE(dumper.FindMapping(reinterpret_cast<void*>(getpid)));
+  ASSERT_TRUE(dumper.FindMapping(reinterpret_cast<void*>(printf)));
+  ASSERT_FALSE(dumper.FindMapping(NULL));
+}
+
+TEST_F(LinuxPtraceDumperChildTest, ThreadList) {
+  LinuxPtraceDumper dumper(getppid());
+  ASSERT_TRUE(dumper.Init());
+
+  ASSERT_GE(dumper.threads().size(), (size_t)1);
+  bool found = false;
+  for (size_t i = 0; i < dumper.threads().size(); ++i) {
+    if (dumper.threads()[i] == getppid()) {
+      ASSERT_FALSE(found);
+      found = true;
+    }
+  }
+  ASSERT_TRUE(found);
+}
+
+// Helper stack class to close a file descriptor and unmap
+// a mmap'ed mapping.
+class StackHelper {
+ public:
+  StackHelper()
+    : fd_(-1), mapping_(NULL), size_(0) {}
+  ~StackHelper() {
+    if (size_)
+      munmap(mapping_, size_);
+    if (fd_ >= 0)
+      close(fd_);
+  }
+  void Init(int fd, char* mapping, size_t size) {
+    fd_ = fd;
+    mapping_ = mapping;
+    size_ = size;
+  }
+
+  char* mapping() const { return mapping_; }
+  size_t size() const { return size_; }
+
+ private:
+  int fd_;
+  char* mapping_;
+  size_t size_;
+};
+
+class LinuxPtraceDumperMappingsTest : public LinuxPtraceDumperChildTest {
+ protected:
+  virtual void SetUp();
+
+  string helper_path_;
+  size_t page_size_;
+  StackHelper helper_;
+};
+
+void LinuxPtraceDumperMappingsTest::SetUp() {
+  helper_path_ = GetHelperBinary();
+  if (helper_path_.empty()) {
+    FAIL() << "Couldn't find helper binary";
+    _exit(1);
+  }
+
+  // mmap two segments out of the helper binary, one
+  // enclosed in the other, but with different protections.
+  page_size_ = sysconf(_SC_PAGESIZE);
+  const size_t kMappingSize = 3 * page_size_;
+  int fd = open(helper_path_.c_str(), O_RDONLY);
+  ASSERT_NE(-1, fd) << "Failed to open file: " << helper_path_
+                    << ", Error: " << strerror(errno);
+  char* mapping =
+    reinterpret_cast<char*>(mmap(NULL,
+                                 kMappingSize,
+                                 PROT_READ,
+                                 MAP_SHARED,
+                                 fd,
+                                 0));
+  ASSERT_TRUE(mapping);
+
+  // Ensure that things get cleaned up.
+  helper_.Init(fd, mapping, kMappingSize);
+
+  // Carve a page out of the first mapping with different permissions.
+  char* inside_mapping =  reinterpret_cast<char*>(
+      mmap(mapping + 2 * page_size_,
+           page_size_,
+           PROT_NONE,
+           MAP_SHARED | MAP_FIXED,
+           fd,
+           // Map a different offset just to
+           // better test real-world conditions.
+           page_size_));
+  ASSERT_TRUE(inside_mapping);
+
+  LinuxPtraceDumperChildTest::SetUp();
+}
+
+TEST_F(LinuxPtraceDumperMappingsTest, MergedMappings) {
+  // Now check that LinuxPtraceDumper interpreted the mappings properly.
+  LinuxPtraceDumper dumper(getppid());
+  ASSERT_TRUE(dumper.Init());
+  int mapping_count = 0;
+  for (unsigned i = 0; i < dumper.mappings().size(); ++i) {
+    const MappingInfo& mapping = *dumper.mappings()[i];
+    if (strcmp(mapping.name, this->helper_path_.c_str()) == 0) {
+      // This mapping should encompass the entire original mapped
+      // range.
+      EXPECT_EQ(reinterpret_cast<uintptr_t>(this->helper_.mapping()),
+                mapping.start_addr);
+      EXPECT_EQ(this->helper_.size(), mapping.size);
+      EXPECT_EQ(0U, mapping.offset);
+      mapping_count++;
+    }
+  }
+  EXPECT_EQ(1, mapping_count);
+}
+
+TEST_F(LinuxPtraceDumperChildTest, BuildProcPath) {
+  const pid_t pid = getppid();
+  LinuxPtraceDumper dumper(pid);
+
+  char maps_path[NAME_MAX] = "";
+  char maps_path_expected[NAME_MAX];
+  snprintf(maps_path_expected, sizeof(maps_path_expected),
+           "/proc/%d/maps", pid);
+  EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
+  EXPECT_STREQ(maps_path_expected, maps_path);
+
+  EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, 0, "maps"));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
+
+  char long_node[NAME_MAX];
+  size_t long_node_len = NAME_MAX - strlen("/proc/123") - 1;
+  memset(long_node, 'a', long_node_len);
+  long_node[long_node_len] = '\0';
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, 123, long_node));
+}
+
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+// Ensure that the linux-gate VDSO is included in the mapping list.
+TEST_F(LinuxPtraceDumperChildTest, MappingsIncludeLinuxGate) {
+  LinuxPtraceDumper dumper(getppid());
+  ASSERT_TRUE(dumper.Init());
+
+  void* linux_gate_loc =
+    reinterpret_cast<void *>(dumper.auxv()[AT_SYSINFO_EHDR]);
+  ASSERT_TRUE(linux_gate_loc);
+  bool found_linux_gate = false;
+
+  const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
+  const MappingInfo* mapping;
+  for (unsigned i = 0; i < mappings.size(); ++i) {
+    mapping = mappings[i];
+    if (!strcmp(mapping->name, kLinuxGateLibraryName)) {
+      found_linux_gate = true;
+      break;
+    }
+  }
+  EXPECT_TRUE(found_linux_gate);
+  EXPECT_EQ(linux_gate_loc, reinterpret_cast<void*>(mapping->start_addr));
+  EXPECT_EQ(0, memcmp(linux_gate_loc, ELFMAG, SELFMAG));
+}
+
+// Ensure that the linux-gate VDSO can generate a non-zeroed File ID.
+TEST_F(LinuxPtraceDumperChildTest, LinuxGateMappingID) {
+  LinuxPtraceDumper dumper(getppid());
+  ASSERT_TRUE(dumper.Init());
+
+  bool found_linux_gate = false;
+  const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
+  unsigned index = 0;
+  for (unsigned i = 0; i < mappings.size(); ++i) {
+    if (!strcmp(mappings[i]->name, kLinuxGateLibraryName)) {
+      found_linux_gate = true;
+      index = i;
+      break;
+    }
+  }
+  ASSERT_TRUE(found_linux_gate);
+
+  // Need to suspend the child so ptrace actually works.
+  ASSERT_TRUE(dumper.ThreadsSuspend());
+  id_vector identifier(make_vector());
+  ASSERT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[index],
+                                                 true,
+                                                 index,
+                                                 identifier));
+
+  id_vector empty_identifier(make_vector());
+  empty_identifier.resize(kDefaultBuildIdSize, 0);
+  EXPECT_NE(empty_identifier, identifier);
+  EXPECT_TRUE(dumper.ThreadsResume());
+}
+#endif
+
+TEST_F(LinuxPtraceDumperChildTest, FileIDsMatch) {
+  // Calculate the File ID of our binary using both
+  // FileID::ElfFileIdentifier and LinuxDumper::ElfFileIdentifierForMapping
+  // and ensure that we get the same result from both.
+  char exe_name[PATH_MAX];
+  ASSERT_TRUE(SafeReadLink("/proc/self/exe", exe_name));
+
+  LinuxPtraceDumper dumper(getppid());
+  ASSERT_TRUE(dumper.Init());
+  const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
+  bool found_exe = false;
+  unsigned i;
+  for (i = 0; i < mappings.size(); ++i) {
+    const MappingInfo* mapping = mappings[i];
+    if (!strcmp(mapping->name, exe_name)) {
+      found_exe = true;
+      break;
+    }
+  }
+  ASSERT_TRUE(found_exe);
+
+  id_vector identifier1(make_vector());
+  id_vector identifier2(make_vector());
+  EXPECT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[i], true, i,
+                                                 identifier1));
+  FileID fileid(exe_name);
+  EXPECT_TRUE(fileid.ElfFileIdentifier(identifier2));
+
+  string identifier_string1 =
+      FileID::ConvertIdentifierToUUIDString(identifier1);
+  string identifier_string2 =
+      FileID::ConvertIdentifierToUUIDString(identifier2);
+  EXPECT_EQ(identifier_string1, identifier_string2);
+}
+
+/* Get back to normal behavior of TEST*() macros wrt TestBody. */
+#undef TestBody
+
+TEST(LinuxPtraceDumperTest, VerifyStackReadWithMultipleThreads) {
+  static const size_t kNumberOfThreadsInHelperProgram = 5;
+
+  pid_t child_pid = SetupChildProcess(kNumberOfThreadsInHelperProgram);
+  ASSERT_NE(child_pid, -1);
+
+  // Children are ready now.
+  LinuxPtraceDumper dumper(child_pid);
+  ASSERT_TRUE(dumper.Init());
+#if defined(THREAD_SANITIZER)
+  EXPECT_GE(dumper.threads().size(), (size_t)kNumberOfThreadsInHelperProgram);
+#else
+  EXPECT_EQ(dumper.threads().size(), (size_t)kNumberOfThreadsInHelperProgram);
+#endif
+  EXPECT_TRUE(dumper.ThreadsSuspend());
+
+  ThreadInfo one_thread;
+  size_t matching_threads = 0;
+  for (size_t i = 0; i < dumper.threads().size(); ++i) {
+    EXPECT_TRUE(dumper.GetThreadInfoByIndex(i, &one_thread));
+    const void* stack;
+    size_t stack_len;
+    EXPECT_TRUE(dumper.GetStackInfo(&stack, &stack_len,
+        one_thread.stack_pointer));
+    // In the helper program, we stored a pointer to the thread id in a
+    // specific register. Check that we can recover its value.
+#if defined(__ARM_EABI__)
+    pid_t* process_tid_location = (pid_t*)(one_thread.regs.uregs[3]);
+#elif defined(__aarch64__)
+    pid_t* process_tid_location = (pid_t*)(one_thread.regs.regs[3]);
+#elif defined(__i386)
+    pid_t* process_tid_location = (pid_t*)(one_thread.regs.ecx);
+#elif defined(__x86_64)
+    pid_t* process_tid_location = (pid_t*)(one_thread.regs.rcx);
+#elif defined(__mips__)
+    pid_t* process_tid_location =
+        reinterpret_cast<pid_t*>(one_thread.mcontext.gregs[1]);
+#else
+#error This test has not been ported to this platform.
+#endif
+    pid_t one_thread_id;
+    dumper.CopyFromProcess(&one_thread_id,
+                           dumper.threads()[i],
+                           process_tid_location,
+                           4);
+    matching_threads += (dumper.threads()[i] == one_thread_id) ? 1 : 0;
+  }
+  EXPECT_EQ(matching_threads, kNumberOfThreadsInHelperProgram);
+  EXPECT_TRUE(dumper.ThreadsResume());
+  kill(child_pid, SIGKILL);
+
+  // Reap child
+  int status;
+  ASSERT_NE(-1, HANDLE_EINTR(waitpid(child_pid, &status, 0)));
+  ASSERT_TRUE(WIFSIGNALED(status));
+  ASSERT_EQ(SIGKILL, WTERMSIG(status));
+}
+
+TEST_F(LinuxPtraceDumperTest, SanitizeStackCopy) {
+  static const size_t kNumberOfThreadsInHelperProgram = 1;
+
+  pid_t child_pid = SetupChildProcess(kNumberOfThreadsInHelperProgram);
+  ASSERT_NE(child_pid, -1);
+
+  LinuxPtraceDumper dumper(child_pid);
+  ASSERT_TRUE(dumper.Init());
+  EXPECT_TRUE(dumper.ThreadsSuspend());
+
+  ThreadInfo thread_info;
+  EXPECT_TRUE(dumper.GetThreadInfoByIndex(0, &thread_info));
+
+  const uintptr_t defaced =
+#if defined(__LP64__)
+      0x0defaced0defaced;
+#else
+      0x0defaced;
+#endif
+
+  uintptr_t simulated_stack[2];
+
+  // Pointers into the stack shouldn't be sanitized.
+  memset(simulated_stack, 0xff, sizeof(simulated_stack));
+  simulated_stack[1] = thread_info.stack_pointer;
+  dumper.SanitizeStackCopy(reinterpret_cast<uint8_t*>(&simulated_stack),
+                           sizeof(simulated_stack), thread_info.stack_pointer,
+                           sizeof(uintptr_t));
+  ASSERT_NE(simulated_stack[1], defaced);
+
+  // Memory prior to the stack pointer should be cleared.
+  ASSERT_EQ(simulated_stack[0], 0u);
+
+  // Small integers should not be sanitized.
+  for (int i = -4096; i <= 4096; ++i) {
+    memset(simulated_stack, 0, sizeof(simulated_stack));
+    simulated_stack[0] = static_cast<uintptr_t>(i);
+    dumper.SanitizeStackCopy(reinterpret_cast<uint8_t*>(&simulated_stack),
+                             sizeof(simulated_stack), thread_info.stack_pointer,
+                             0u);
+    ASSERT_NE(simulated_stack[0], defaced);
+  }
+
+  // The instruction pointer definitely should point into an executable mapping.
+  const MappingInfo* mapping_info = dumper.FindMappingNoBias(
+      reinterpret_cast<uintptr_t>(thread_info.GetInstructionPointer()));
+  ASSERT_NE(mapping_info, nullptr);
+  ASSERT_TRUE(mapping_info->exec);
+
+  // Pointers to code shouldn't be sanitized.
+  memset(simulated_stack, 0, sizeof(simulated_stack));
+  simulated_stack[1] = thread_info.GetInstructionPointer();
+  dumper.SanitizeStackCopy(reinterpret_cast<uint8_t*>(&simulated_stack),
+                           sizeof(simulated_stack), thread_info.stack_pointer,
+                           0u);
+  ASSERT_NE(simulated_stack[0], defaced);
+
+  // String fragments should be sanitized.
+  memcpy(simulated_stack, "abcdefghijklmnop", sizeof(simulated_stack));
+  dumper.SanitizeStackCopy(reinterpret_cast<uint8_t*>(&simulated_stack),
+                           sizeof(simulated_stack), thread_info.stack_pointer,
+                           0u);
+  ASSERT_EQ(simulated_stack[0], defaced);
+  ASSERT_EQ(simulated_stack[1], defaced);
+
+  // Heap pointers should be sanititzed.
+#if defined(__ARM_EABI__)
+  uintptr_t heap_addr = thread_info.regs.uregs[3];
+#elif defined(__aarch64__)
+  uintptr_t heap_addr = thread_info.regs.regs[3];
+#elif defined(__i386)
+  uintptr_t heap_addr = thread_info.regs.ecx;
+#elif defined(__x86_64)
+  uintptr_t heap_addr = thread_info.regs.rcx;
+#elif defined(__mips__)
+  uintptr_t heap_addr = thread_info.mcontext.gregs[1];
+#else
+#error This test has not been ported to this platform.
+#endif
+  memset(simulated_stack, 0, sizeof(simulated_stack));
+  simulated_stack[0] = heap_addr;
+  dumper.SanitizeStackCopy(reinterpret_cast<uint8_t*>(&simulated_stack),
+                           sizeof(simulated_stack), thread_info.stack_pointer,
+                           0u);
+  ASSERT_EQ(simulated_stack[0], defaced);
+
+  EXPECT_TRUE(dumper.ThreadsResume());
+  kill(child_pid, SIGKILL);
+
+  // Reap child.
+  int status;
+  ASSERT_NE(-1, HANDLE_EINTR(waitpid(child_pid, &status, 0)));
+  ASSERT_TRUE(WIFSIGNALED(status));
+  ASSERT_EQ(SIGKILL, WTERMSIG(status));
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer.cc
new file mode 100644
index 0000000000..03066e9110
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer.cc
@@ -0,0 +1,1562 @@
+// Copyright (c) 2010, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This code writes out minidump files:
+//   http://msdn.microsoft.com/en-us/library/ms680378(VS.85,loband).aspx
+//
+// Minidumps are a Microsoft format which Breakpad uses for recording crash
+// dumps. This code has to run in a compromised environment (the address space
+// may have received SIGSEGV), thus the following rules apply:
+//   * You may not enter the dynamic linker. This means that we cannot call
+//     any symbols in a shared library (inc libc). Because of this we replace
+//     libc functions in linux_libc_support.h.
+//   * You may not call syscalls via the libc wrappers. This rule is a subset
+//     of the first rule but it bears repeating. We have direct wrappers
+//     around the system calls in linux_syscall_support.h.
+//   * You may not malloc. There's an alternative allocator in memory.h and
+//     a canonical instance in the LinuxDumper object. We use the placement
+//     new form to allocate objects and we don't delete them.
+
+#include "linux/handler/minidump_descriptor.h"
+#include "linux/minidump_writer/minidump_writer.h"
+#include "minidump_file_writer-inl.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <link.h>
+#include <stdio.h>
+#if defined(__ANDROID__)
+#include <sys/system_properties.h>
+#endif
+#include <sys/types.h>
+#include <sys/ucontext.h>
+#include <sys/user.h>
+#include <sys/utsname.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <algorithm>
+
+#include "linux/dump_writer_common/thread_info.h"
+#include "linux/dump_writer_common/ucontext_reader.h"
+#include "linux/handler/exception_handler.h"
+#include "linux/minidump_writer/cpu_set.h"
+#include "linux/minidump_writer/line_reader.h"
+#include "linux/minidump_writer/linux_dumper.h"
+#include "linux/minidump_writer/linux_ptrace_dumper.h"
+#include "linux/minidump_writer/proc_cpuinfo_reader.h"
+#include "minidump_file_writer.h"
+#include "common/linux/file_id.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/minidump_type_helper.h"
+#include "google_breakpad/common/minidump_format.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+namespace {
+
+using google_breakpad::AppMemoryList;
+using google_breakpad::auto_wasteful_vector;
+using google_breakpad::ExceptionHandler;
+using google_breakpad::CpuSet;
+using google_breakpad::kDefaultBuildIdSize;
+using google_breakpad::LineReader;
+using google_breakpad::LinuxDumper;
+using google_breakpad::LinuxPtraceDumper;
+using google_breakpad::MDTypeHelper;
+using google_breakpad::MappingEntry;
+using google_breakpad::MappingInfo;
+using google_breakpad::MappingList;
+using google_breakpad::MinidumpFileWriter;
+using google_breakpad::PageAllocator;
+using google_breakpad::ProcCpuInfoReader;
+using google_breakpad::RawContextCPU;
+using google_breakpad::ThreadInfo;
+using google_breakpad::TypedMDRVA;
+using google_breakpad::UContextReader;
+using google_breakpad::UntypedMDRVA;
+using google_breakpad::wasteful_vector;
+
+typedef MDTypeHelper<sizeof(void*)>::MDRawDebug MDRawDebug;
+typedef MDTypeHelper<sizeof(void*)>::MDRawLinkMap MDRawLinkMap;
+
+class MinidumpWriter {
+ public:
+  // The following kLimit* constants are for when minidump_size_limit_ is set
+  // and the minidump size might exceed it.
+  //
+  // Estimate for how big each thread's stack will be (in bytes).
+  static const unsigned kLimitAverageThreadStackLength = 8 * 1024;
+  // Number of threads whose stack size we don't want to limit.  These base
+  // threads will simply be the first N threads returned by the dumper (although
+  // the crashing thread will never be limited).  Threads beyond this count are
+  // the extra threads.
+  static const unsigned kLimitBaseThreadCount = 20;
+  // Maximum stack size to dump for any extra thread (in bytes).
+  static const unsigned kLimitMaxExtraThreadStackLen = 2 * 1024;
+  // Make sure this number of additional bytes can fit in the minidump
+  // (exclude the stack data).
+  static const unsigned kLimitMinidumpFudgeFactor = 64 * 1024;
+
+  MinidumpWriter(const char* minidump_path,
+                 int minidump_fd,
+                 const ExceptionHandler::CrashContext* context,
+                 const MappingList& mappings,
+                 const AppMemoryList& appmem,
+                 bool skip_stacks_if_mapping_unreferenced,
+                 uintptr_t principal_mapping_address,
+                 bool sanitize_stacks,
+                 LinuxDumper* dumper)
+      : fd_(minidump_fd),
+        path_(minidump_path),
+        ucontext_(context ? &context->context : NULL),
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+        float_state_(context ? &context->float_state : NULL),
+#endif
+        dumper_(dumper),
+        minidump_size_limit_(-1),
+        memory_blocks_(dumper_->allocator()),
+        mapping_list_(mappings),
+        app_memory_list_(appmem),
+        skip_stacks_if_mapping_unreferenced_(
+            skip_stacks_if_mapping_unreferenced),
+        principal_mapping_address_(principal_mapping_address),
+        principal_mapping_(nullptr),
+    sanitize_stacks_(sanitize_stacks) {
+    // Assert there should be either a valid fd or a valid path, not both.
+    assert(fd_ != -1 || minidump_path);
+    assert(fd_ == -1 || !minidump_path);
+  }
+
+  bool Init() {
+    if (!dumper_->Init())
+      return false;
+
+    if (!dumper_->ThreadsSuspend() || !dumper_->LateInit())
+      return false;
+
+    if (skip_stacks_if_mapping_unreferenced_) {
+      principal_mapping_ =
+          dumper_->FindMappingNoBias(principal_mapping_address_);
+      if (!CrashingThreadReferencesPrincipalMapping())
+        return false;
+    }
+
+    if (fd_ != -1)
+      minidump_writer_.SetFile(fd_);
+    else if (!minidump_writer_.Open(path_))
+      return false;
+
+    return true;
+  }
+
+  ~MinidumpWriter() {
+    // Don't close the file descriptor when it's been provided explicitly.
+    // Callers might still need to use it.
+    if (fd_ == -1)
+      minidump_writer_.Close();
+    dumper_->ThreadsResume();
+  }
+
+  bool CrashingThreadReferencesPrincipalMapping() {
+    if (!ucontext_ || !principal_mapping_)
+      return false;
+
+    const uintptr_t low_addr =
+        principal_mapping_->system_mapping_info.start_addr;
+    const uintptr_t high_addr =
+        principal_mapping_->system_mapping_info.end_addr;
+
+    const uintptr_t stack_pointer = UContextReader::GetStackPointer(ucontext_);
+    const uintptr_t pc = UContextReader::GetInstructionPointer(ucontext_);
+
+    if (pc >= low_addr && pc < high_addr)
+      return true;
+
+    uint8_t* stack_copy;
+    const void* stack;
+    size_t stack_len;
+
+    if (!dumper_->GetStackInfo(&stack, &stack_len, stack_pointer))
+      return false;
+
+    stack_copy = reinterpret_cast<uint8_t*>(Alloc(stack_len));
+    dumper_->CopyFromProcess(stack_copy, GetCrashThread(), stack, stack_len);
+
+    uintptr_t stack_pointer_offset =
+        stack_pointer - reinterpret_cast<uintptr_t>(stack);
+
+    return dumper_->StackHasPointerToMapping(
+        stack_copy, stack_len, stack_pointer_offset, *principal_mapping_);
+  }
+
+  bool Dump() {
+    // A minidump file contains a number of tagged streams. This is the number
+    // of stream which we write.
+    unsigned kNumWriters = 14;
+
+    TypedMDRVA<MDRawDirectory> dir(&minidump_writer_);
+    {
+      // Ensure the header gets flushed, as that happens in the destructor.
+      // If we crash somewhere below, we should have a mostly-intact dump
+      TypedMDRVA<MDRawHeader> header(&minidump_writer_);
+      if (!header.Allocate())
+        return false;
+
+      if (!dir.AllocateArray(kNumWriters))
+        return false;
+
+      my_memset(header.get(), 0, sizeof(MDRawHeader));
+
+      header.get()->signature = MD_HEADER_SIGNATURE;
+      header.get()->version = MD_HEADER_VERSION;
+      header.get()->time_date_stamp = time(NULL);
+      header.get()->stream_count = kNumWriters;
+      header.get()->stream_directory_rva = dir.position();
+    }
+
+    unsigned dir_index = 0;
+    MDRawDirectory dirent;
+
+    if (!WriteThreadListStream(&dirent))
+      return false;
+    dir.CopyIndex(dir_index++, &dirent);
+
+    if (!WriteThreadNamesStream(&dirent))
+      return false;
+    dir.CopyIndex(dir_index++, &dirent);
+
+    if (!WriteMappings(&dirent))
+      return false;
+    dir.CopyIndex(dir_index++, &dirent);
+
+    if (!WriteAppMemory())
+      return false;
+
+    if (!WriteMemoryListStream(&dirent))
+      return false;
+    dir.CopyIndex(dir_index++, &dirent);
+
+    if (!WriteExceptionStream(&dirent))
+      return false;
+    dir.CopyIndex(dir_index++, &dirent);
+
+    if (!WriteSystemInfoStream(&dirent))
+      return false;
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_CPU_INFO;
+    if (!WriteFile(&dirent.location, "/proc/cpuinfo"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_PROC_STATUS;
+    if (!WriteProcFile(&dirent.location, GetCrashThread(), "status"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_LSB_RELEASE;
+    if (!WriteFile(&dirent.location, "/etc/lsb-release") &&
+        !WriteFile(&dirent.location, "/etc/os-release")) {
+      NullifyDirectoryEntry(&dirent);
+    }
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_CMD_LINE;
+    if (!WriteProcFile(&dirent.location, GetCrashThread(), "cmdline"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_ENVIRON;
+    if (!WriteProcFile(&dirent.location, GetCrashThread(), "environ"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_AUXV;
+    if (!WriteProcFile(&dirent.location, GetCrashThread(), "auxv"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_MAPS;
+    if (!WriteProcFile(&dirent.location, GetCrashThread(), "maps"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_DSO_DEBUG;
+    if (!WriteDSODebugStream(&dirent))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    // If you add more directory entries, don't forget to update kNumWriters,
+    // above.
+
+    dumper_->ThreadsResume();
+    return true;
+  }
+
+  bool FillThreadStack(MDRawThread* thread, uintptr_t stack_pointer,
+                       uintptr_t pc, int max_stack_len, uint8_t** stack_copy) {
+    *stack_copy = NULL;
+    const void* stack;
+    size_t stack_len;
+
+    thread->stack.start_of_memory_range = stack_pointer;
+    thread->stack.memory.data_size = 0;
+    thread->stack.memory.rva = minidump_writer_.position();
+
+    if (dumper_->GetStackInfo(&stack, &stack_len, stack_pointer)) {
+      if (max_stack_len >= 0 &&
+          stack_len > static_cast<unsigned int>(max_stack_len)) {
+        stack_len = max_stack_len;
+        // Skip empty chunks of length max_stack_len.
+        uintptr_t int_stack = reinterpret_cast<uintptr_t>(stack);
+        if (max_stack_len > 0) {
+          while (int_stack + max_stack_len < stack_pointer) {
+            int_stack += max_stack_len;
+          }
+        }
+        stack = reinterpret_cast<const void*>(int_stack);
+      }
+      *stack_copy = reinterpret_cast<uint8_t*>(Alloc(stack_len));
+      dumper_->CopyFromProcess(*stack_copy, thread->thread_id, stack,
+                               stack_len);
+
+      uintptr_t stack_pointer_offset =
+          stack_pointer - reinterpret_cast<uintptr_t>(stack);
+      if (skip_stacks_if_mapping_unreferenced_) {
+        if (!principal_mapping_) {
+          return true;
+        }
+        uintptr_t low_addr = principal_mapping_->system_mapping_info.start_addr;
+        uintptr_t high_addr = principal_mapping_->system_mapping_info.end_addr;
+        if ((pc < low_addr || pc > high_addr) &&
+            !dumper_->StackHasPointerToMapping(*stack_copy, stack_len,
+                                               stack_pointer_offset,
+                                               *principal_mapping_)) {
+          return true;
+        }
+      }
+
+      if (sanitize_stacks_) {
+        dumper_->SanitizeStackCopy(*stack_copy, stack_len, stack_pointer,
+                                   stack_pointer_offset);
+      }
+
+      UntypedMDRVA memory(&minidump_writer_);
+      if (!memory.Allocate(stack_len))
+        return false;
+      memory.Copy(*stack_copy, stack_len);
+      thread->stack.start_of_memory_range = reinterpret_cast<uintptr_t>(stack);
+      thread->stack.memory = memory.location();
+      memory_blocks_.push_back(thread->stack);
+    }
+    return true;
+  }
+
+  // Write information about the threads.
+  bool WriteThreadListStream(MDRawDirectory* dirent) {
+    const unsigned num_threads = dumper_->threads().size();
+
+    TypedMDRVA<uint32_t> list(&minidump_writer_);
+    if (!list.AllocateObjectAndArray(num_threads, sizeof(MDRawThread)))
+      return false;
+
+    dirent->stream_type = MD_THREAD_LIST_STREAM;
+    dirent->location = list.location();
+
+    *list.get() = num_threads;
+
+    // If there's a minidump size limit, check if it might be exceeded.  Since
+    // most of the space is filled with stack data, just check against that.
+    // If this expects to exceed the limit, set extra_thread_stack_len such
+    // that any thread beyond the first kLimitBaseThreadCount threads will
+    // have only kLimitMaxExtraThreadStackLen bytes dumped.
+    int extra_thread_stack_len = -1;  // default to no maximum
+    if (minidump_size_limit_ >= 0) {
+      const unsigned estimated_total_stack_size = num_threads *
+          kLimitAverageThreadStackLength;
+      const off_t estimated_minidump_size = minidump_writer_.position() +
+          estimated_total_stack_size + kLimitMinidumpFudgeFactor;
+      if (estimated_minidump_size > minidump_size_limit_)
+        extra_thread_stack_len = kLimitMaxExtraThreadStackLen;
+    }
+
+    for (unsigned i = 0; i < num_threads; ++i) {
+      MDRawThread thread;
+      my_memset(&thread, 0, sizeof(thread));
+      thread.thread_id = dumper_->threads()[i];
+
+      // We have a different source of information for the crashing thread. If
+      // we used the actual state of the thread we would find it running in the
+      // signal handler with the alternative stack, which would be deeply
+      // unhelpful.
+      if (static_cast<pid_t>(thread.thread_id) == GetCrashThread() &&
+          ucontext_ &&
+          !dumper_->IsPostMortem()) {
+        uint8_t* stack_copy;
+        const uintptr_t stack_ptr = UContextReader::GetStackPointer(ucontext_);
+        if (!FillThreadStack(&thread, stack_ptr,
+                             UContextReader::GetInstructionPointer(ucontext_),
+                             -1, &stack_copy))
+          return false;
+
+        // Copy 256 bytes around crashing instruction pointer to minidump.
+        const size_t kIPMemorySize = 256;
+        uint64_t ip = UContextReader::GetInstructionPointer(ucontext_);
+        // Bound it to the upper and lower bounds of the memory map
+        // it's contained within. If it's not in mapped memory,
+        // don't bother trying to write it.
+        bool ip_is_mapped = false;
+        MDMemoryDescriptor ip_memory_d;
+        for (unsigned j = 0; j < dumper_->mappings().size(); ++j) {
+          const MappingInfo& mapping = *dumper_->mappings()[j];
+          if (ip >= mapping.start_addr &&
+              ip < mapping.start_addr + mapping.size) {
+            ip_is_mapped = true;
+            // Try to get 128 bytes before and after the IP, but
+            // settle for whatever's available.
+            ip_memory_d.start_of_memory_range =
+              std::max(mapping.start_addr,
+                       uintptr_t(ip - (kIPMemorySize / 2)));
+            uintptr_t end_of_range =
+              std::min(uintptr_t(ip + (kIPMemorySize / 2)),
+                       uintptr_t(mapping.start_addr + mapping.size));
+            ip_memory_d.memory.data_size =
+              end_of_range - ip_memory_d.start_of_memory_range;
+            break;
+          }
+        }
+
+        if (ip_is_mapped) {
+          UntypedMDRVA ip_memory(&minidump_writer_);
+          if (!ip_memory.Allocate(ip_memory_d.memory.data_size))
+            return false;
+          uint8_t* memory_copy =
+              reinterpret_cast<uint8_t*>(Alloc(ip_memory_d.memory.data_size));
+          dumper_->CopyFromProcess(
+              memory_copy,
+              thread.thread_id,
+              reinterpret_cast<void*>(ip_memory_d.start_of_memory_range),
+              ip_memory_d.memory.data_size);
+          ip_memory.Copy(memory_copy, ip_memory_d.memory.data_size);
+          ip_memory_d.memory = ip_memory.location();
+          memory_blocks_.push_back(ip_memory_d);
+        }
+
+        TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
+        if (!cpu.Allocate())
+          return false;
+        my_memset(cpu.get(), 0, sizeof(RawContextCPU));
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+        UContextReader::FillCPUContext(cpu.get(), ucontext_, float_state_);
+#else
+        UContextReader::FillCPUContext(cpu.get(), ucontext_);
+#endif
+        thread.thread_context = cpu.location();
+        crashing_thread_context_ = cpu.location();
+      } else {
+        ThreadInfo info;
+        if (!dumper_->GetThreadInfoByIndex(i, &info))
+          return false;
+
+        uint8_t* stack_copy;
+        int max_stack_len = -1;  // default to no maximum for this thread
+        if (minidump_size_limit_ >= 0 && i >= kLimitBaseThreadCount)
+          max_stack_len = extra_thread_stack_len;
+        if (!FillThreadStack(&thread, info.stack_pointer,
+                             info.GetInstructionPointer(), max_stack_len,
+                             &stack_copy))
+          return false;
+
+        TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
+        if (!cpu.Allocate())
+          return false;
+        my_memset(cpu.get(), 0, sizeof(RawContextCPU));
+        info.FillCPUContext(cpu.get());
+        thread.thread_context = cpu.location();
+        if (dumper_->threads()[i] == GetCrashThread()) {
+          crashing_thread_context_ = cpu.location();
+          if (!dumper_->IsPostMortem()) {
+            // This is the crashing thread of a live process, but
+            // no context was provided, so set the crash address
+            // while the instruction pointer is already here.
+            dumper_->set_crash_address(info.GetInstructionPointer());
+          }
+        }
+      }
+
+      list.CopyIndexAfterObject(i, &thread, sizeof(thread));
+    }
+
+    return true;
+  }
+
+  bool WriteThreadName(pid_t tid, char* name, MDRawThreadName *thread_name) {
+    MDLocationDescriptor string_location;
+
+    if (!minidump_writer_.WriteString(name, 0, &string_location))
+      return false;
+
+    thread_name->thread_id = tid;
+    thread_name->rva_of_thread_name = string_location.rva;
+    return true;
+  }
+
+  // Write the threads' names.
+  bool WriteThreadNamesStream(MDRawDirectory* thread_names_stream) {
+    TypedMDRVA<MDRawThreadNamesList> list(&minidump_writer_);
+    const unsigned num_threads = dumper_->threads().size();
+
+    if (!list.AllocateObjectAndArray(num_threads, sizeof(MDRawThreadName))) {
+      return false;
+    }
+
+    thread_names_stream->stream_type = MD_THREAD_NAMES_STREAM;
+    thread_names_stream->location = list.location();
+    list.get()->number_of_thread_names = num_threads;
+
+    MDRawThreadName thread_name;
+    int thread_idx = 0;
+
+    for (unsigned int i = 0; i < num_threads; ++i) {
+      const pid_t tid = dumper_->threads()[i];
+      // This is a constant from the Linux kernel, documented in man 5 proc.
+      // The comm entries in /proc are no longer than this.
+      static const size_t TASK_COMM_LEN = 16;
+      char name[TASK_COMM_LEN];
+      memset(&thread_name, 0, sizeof(MDRawThreadName));
+
+      if (dumper_->GetThreadNameByIndex(i, name, sizeof(name))) {
+        if (WriteThreadName(tid, name, &thread_name)) {
+          list.CopyIndexAfterObject(thread_idx++, &thread_name,
+                                  sizeof(MDRawThreadName));
+        }
+      }
+    }
+
+    return true;
+  }
+
+  // Write application-provided memory regions.
+  bool WriteAppMemory() {
+    for (AppMemoryList::const_iterator iter = app_memory_list_.begin();
+         iter != app_memory_list_.end();
+         ++iter) {
+      uint8_t* data_copy =
+        reinterpret_cast<uint8_t*>(dumper_->allocator()->Alloc(iter->length));
+      dumper_->CopyFromProcess(data_copy, GetCrashThread(), iter->ptr,
+                               iter->length);
+
+      UntypedMDRVA memory(&minidump_writer_);
+      if (!memory.Allocate(iter->length)) {
+        return false;
+      }
+      memory.Copy(data_copy, iter->length);
+      MDMemoryDescriptor desc;
+      desc.start_of_memory_range = reinterpret_cast<uintptr_t>(iter->ptr);
+      desc.memory = memory.location();
+      memory_blocks_.push_back(desc);
+    }
+
+    return true;
+  }
+
+  static bool ShouldIncludeMapping(const MappingInfo& mapping) {
+    if (mapping.name[0] == 0 ||  // only want modules with filenames.
+        // Only want to include one mapping per shared lib.
+        // Avoid filtering executable mappings.
+        (mapping.offset != 0 && !mapping.exec) ||
+        mapping.size < 4096) {  // too small to get a signature for.
+      return false;
+    }
+
+    return true;
+  }
+
+  // If there is caller-provided information about this mapping
+  // in the mapping_list_ list, return true. Otherwise, return false.
+  bool HaveMappingInfo(const MappingInfo& mapping) {
+    for (MappingList::const_iterator iter = mapping_list_.begin();
+         iter != mapping_list_.end();
+         ++iter) {
+      // Ignore any mappings that are wholly contained within
+      // mappings in the mapping_info_ list.
+      if (mapping.start_addr >= iter->first.start_addr &&
+          (mapping.start_addr + mapping.size) <=
+          (iter->first.start_addr + iter->first.size)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Write information about the mappings in effect. Because we are using the
+  // minidump format, the information about the mappings is pretty limited.
+  // Because of this, we also include the full, unparsed, /proc/$x/maps file in
+  // another stream in the file.
+  bool WriteMappings(MDRawDirectory* dirent) {
+    const unsigned num_mappings = dumper_->mappings().size();
+    unsigned num_output_mappings = mapping_list_.size();
+
+    for (unsigned i = 0; i < dumper_->mappings().size(); ++i) {
+      const MappingInfo& mapping = *dumper_->mappings()[i];
+      if (ShouldIncludeMapping(mapping) && !HaveMappingInfo(mapping))
+        num_output_mappings++;
+    }
+
+    TypedMDRVA<uint32_t> list(&minidump_writer_);
+    if (num_output_mappings) {
+      if (!list.AllocateObjectAndArray(num_output_mappings, MD_MODULE_SIZE))
+        return false;
+    } else {
+      // Still create the module list stream, although it will have zero
+      // modules.
+      if (!list.Allocate())
+        return false;
+    }
+
+    dirent->stream_type = MD_MODULE_LIST_STREAM;
+    dirent->location = list.location();
+    *list.get() = num_output_mappings;
+
+    // First write all the mappings from the dumper
+    unsigned int j = 0;
+    for (unsigned i = 0; i < num_mappings; ++i) {
+      const MappingInfo& mapping = *dumper_->mappings()[i];
+      if (!ShouldIncludeMapping(mapping) || HaveMappingInfo(mapping))
+        continue;
+
+      MDRawModule mod;
+      if (!FillRawModule(mapping, true, i, &mod, NULL))
+        return false;
+      list.CopyIndexAfterObject(j++, &mod, MD_MODULE_SIZE);
+    }
+    // Next write all the mappings provided by the caller
+    for (MappingList::const_iterator iter = mapping_list_.begin();
+         iter != mapping_list_.end();
+         ++iter) {
+      MDRawModule mod;
+      if (!FillRawModule(iter->first, false, 0, &mod, &iter->second)) {
+        return false;
+      }
+      list.CopyIndexAfterObject(j++, &mod, MD_MODULE_SIZE);
+    }
+
+    return true;
+  }
+
+  // Fill the MDRawModule |mod| with information about the provided
+  // |mapping|. If |identifier| is non-NULL, use it instead of calculating
+  // a file ID from the mapping.
+  bool FillRawModule(const MappingInfo& mapping,
+                     bool member,
+                     unsigned int mapping_id,
+                     MDRawModule* mod,
+                     const std::vector<uint8_t>* identifier) {
+    my_memset(mod, 0, MD_MODULE_SIZE);
+
+    mod->base_of_image = mapping.start_addr;
+    mod->size_of_image = mapping.size;
+
+    auto_wasteful_vector<uint8_t, kDefaultBuildIdSize> identifier_bytes(
+        dumper_->allocator());
+
+    if (identifier) {
+      // GUID was provided by caller.
+      identifier_bytes.insert(identifier_bytes.end(),
+                              identifier->begin(),
+                              identifier->end());
+    } else {
+      // Note: ElfFileIdentifierForMapping() can manipulate the |mapping.name|.
+      if (!dumper_->ElfFileIdentifierForMapping(mapping,
+                                                member,
+                                                mapping_id,
+                                                identifier_bytes)) {
+        identifier_bytes.clear();
+      }
+    }
+
+    if (!identifier_bytes.empty()) {
+      UntypedMDRVA cv(&minidump_writer_);
+      if (!cv.Allocate(MDCVInfoELF_minsize + identifier_bytes.size()))
+        return false;
+
+      const uint32_t cv_signature = MD_CVINFOELF_SIGNATURE;
+      cv.Copy(&cv_signature, sizeof(cv_signature));
+      cv.Copy(cv.position() + sizeof(cv_signature), &identifier_bytes[0],
+              identifier_bytes.size());
+
+      mod->cv_record = cv.location();
+    }
+
+    char file_name[NAME_MAX];
+    char file_path[NAME_MAX];
+    dumper_->GetMappingEffectiveNameAndPath(
+        mapping, file_path, sizeof(file_path), file_name, sizeof(file_name));
+
+    MDLocationDescriptor ld;
+    if (!minidump_writer_.WriteString(file_path, my_strlen(file_path), &ld))
+      return false;
+    mod->module_name_rva = ld.rva;
+    return true;
+  }
+
+  bool WriteMemoryListStream(MDRawDirectory* dirent) {
+    TypedMDRVA<uint32_t> list(&minidump_writer_);
+    if (!memory_blocks_.empty()) {
+      if (!list.AllocateObjectAndArray(memory_blocks_.size(),
+                                       sizeof(MDMemoryDescriptor)))
+        return false;
+    } else {
+      // Still create the memory list stream, although it will have zero
+      // memory blocks.
+      if (!list.Allocate())
+        return false;
+    }
+
+    dirent->stream_type = MD_MEMORY_LIST_STREAM;
+    dirent->location = list.location();
+
+    *list.get() = memory_blocks_.size();
+
+    for (size_t i = 0; i < memory_blocks_.size(); ++i) {
+      list.CopyIndexAfterObject(i, &memory_blocks_[i],
+                                sizeof(MDMemoryDescriptor));
+    }
+    return true;
+  }
+
+  bool WriteExceptionStream(MDRawDirectory* dirent) {
+    TypedMDRVA<MDRawExceptionStream> exc(&minidump_writer_);
+    if (!exc.Allocate())
+      return false;
+
+    MDRawExceptionStream* stream = exc.get();
+    my_memset(stream, 0, sizeof(MDRawExceptionStream));
+
+    dirent->stream_type = MD_EXCEPTION_STREAM;
+    dirent->location = exc.location();
+
+    stream->thread_id = GetCrashThread();
+    stream->exception_record.exception_code = dumper_->crash_signal();
+    stream->exception_record.exception_flags = dumper_->crash_signal_code();
+    stream->exception_record.exception_address = dumper_->crash_address();
+    const std::vector<uint64_t> crash_exception_info =
+        dumper_->crash_exception_info();
+    stream->exception_record.number_parameters = crash_exception_info.size();
+    memcpy(stream->exception_record.exception_information,
+           crash_exception_info.data(),
+           sizeof(uint64_t) * crash_exception_info.size());
+    stream->thread_context = crashing_thread_context_;
+
+    return true;
+  }
+
+  bool WriteSystemInfoStream(MDRawDirectory* dirent) {
+    TypedMDRVA<MDRawSystemInfo> si(&minidump_writer_);
+    if (!si.Allocate())
+      return false;
+    my_memset(si.get(), 0, sizeof(MDRawSystemInfo));
+
+    dirent->stream_type = MD_SYSTEM_INFO_STREAM;
+    dirent->location = si.location();
+
+    WriteCPUInformation(si.get());
+    WriteOSInformation(si.get());
+
+    return true;
+  }
+
+  bool WriteDSODebugStream(MDRawDirectory* dirent) {
+    ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr) *>(dumper_->auxv()[AT_PHDR]);
+    char* base;
+    int phnum = dumper_->auxv()[AT_PHNUM];
+    if (!phnum || !phdr)
+      return false;
+
+    // Assume the program base is at the beginning of the same page as the PHDR
+    base = reinterpret_cast<char *>(reinterpret_cast<uintptr_t>(phdr) & ~0xfff);
+
+    // Search for the program PT_DYNAMIC segment
+    ElfW(Addr) dyn_addr = 0;
+    for (; phnum >= 0; phnum--, phdr++) {
+      ElfW(Phdr) ph;
+      if (!dumper_->CopyFromProcess(&ph, dumper_->pid(), phdr, sizeof(ph)))
+        return false;
+
+      // Adjust base address with the virtual address of the PT_LOAD segment
+      // corresponding to offset 0
+      if (ph.p_type == PT_LOAD && ph.p_offset == 0) {
+        base -= ph.p_vaddr;
+      }
+      if (ph.p_type == PT_DYNAMIC) {
+        dyn_addr = ph.p_vaddr;
+      }
+    }
+    if (!dyn_addr)
+      return false;
+
+    ElfW(Dyn) *dynamic = reinterpret_cast<ElfW(Dyn) *>(dyn_addr + base);
+
+    // The dynamic linker makes information available that helps gdb find all
+    // DSOs loaded into the program. If this information is indeed available,
+    // dump it to a MD_LINUX_DSO_DEBUG stream.
+    struct r_debug* r_debug = NULL;
+    uint32_t dynamic_length = 0;
+
+    for (int i = 0; ; ++i) {
+      ElfW(Dyn) dyn;
+      dynamic_length += sizeof(dyn);
+      if (!dumper_->CopyFromProcess(&dyn, dumper_->pid(), dynamic + i, sizeof(dyn))) {
+        return false;
+      }
+
+#ifdef __mips__
+      const int32_t debug_tag = DT_MIPS_RLD_MAP;
+#else
+      const int32_t debug_tag = DT_DEBUG;
+#endif
+      if (dyn.d_tag == debug_tag) {
+        r_debug = reinterpret_cast<struct r_debug*>(dyn.d_un.d_ptr);
+        continue;
+      } else if (dyn.d_tag == DT_NULL) {
+        break;
+      }
+    }
+
+    // The "r_map" field of that r_debug struct contains a linked list of all
+    // loaded DSOs.
+    // Our list of DSOs potentially is different from the ones in the crashing
+    // process. So, we have to be careful to never dereference pointers
+    // directly. Instead, we use CopyFromProcess() everywhere.
+    // See <link.h> for a more detailed discussion of the how the dynamic
+    // loader communicates with debuggers.
+
+    // Count the number of loaded DSOs
+    int dso_count = 0;
+    struct r_debug debug_entry;
+    if (!dumper_->CopyFromProcess(&debug_entry, dumper_->pid(), r_debug,
+                                  sizeof(debug_entry))) {
+      return false;
+    }
+    for (struct link_map* ptr = debug_entry.r_map; ptr; ) {
+      struct link_map map;
+      if (!dumper_->CopyFromProcess(&map, dumper_->pid(), ptr, sizeof(map)))
+        return false;
+
+      ptr = map.l_next;
+      dso_count++;
+    }
+
+    MDRVA linkmap_rva = MinidumpFileWriter::kInvalidMDRVA;
+    if (dso_count > 0) {
+      // If we have at least one DSO, create an array of MDRawLinkMap
+      // entries in the minidump file.
+      TypedMDRVA<MDRawLinkMap> linkmap(&minidump_writer_);
+      if (!linkmap.AllocateArray(dso_count))
+        return false;
+      linkmap_rva = linkmap.location().rva;
+      int idx = 0;
+
+      // Iterate over DSOs and write their information to mini dump
+      for (struct link_map* ptr = debug_entry.r_map; ptr; ) {
+        struct link_map map;
+        if (!dumper_->CopyFromProcess(&map, dumper_->pid(), ptr, sizeof(map)))
+          return  false;
+
+        ptr = map.l_next;
+        char filename[257] = { 0 };
+        if (map.l_name) {
+          dumper_->CopyFromProcess(filename, dumper_->pid(), map.l_name,
+                                   sizeof(filename) - 1);
+        }
+        MDLocationDescriptor location;
+        if (!minidump_writer_.WriteString(filename, 0, &location))
+          return false;
+        MDRawLinkMap entry;
+        entry.name = location.rva;
+        entry.addr = map.l_addr;
+        entry.ld = reinterpret_cast<uintptr_t>(map.l_ld);
+        linkmap.CopyIndex(idx++, &entry);
+      }
+    }
+
+    // Write MD_LINUX_DSO_DEBUG record
+    TypedMDRVA<MDRawDebug> debug(&minidump_writer_);
+    if (!debug.AllocateObjectAndArray(1, dynamic_length))
+      return false;
+    my_memset(debug.get(), 0, sizeof(MDRawDebug));
+    dirent->stream_type = MD_LINUX_DSO_DEBUG;
+    dirent->location = debug.location();
+
+    debug.get()->version = debug_entry.r_version;
+    debug.get()->map = linkmap_rva;
+    debug.get()->dso_count = dso_count;
+    debug.get()->brk = debug_entry.r_brk;
+    debug.get()->ldbase = debug_entry.r_ldbase;
+    debug.get()->dynamic = reinterpret_cast<uintptr_t>(dynamic);
+
+    wasteful_vector<char> dso_debug_data(dumper_->allocator(), dynamic_length);
+    // The passed-in size to the constructor (above) is only a hint.
+    // Must call .resize() to do actual initialization of the elements.
+    dso_debug_data.resize(dynamic_length);
+    dumper_->CopyFromProcess(&dso_debug_data[0], dumper_->pid(), dynamic,
+                             dynamic_length);
+    debug.CopyIndexAfterObject(0, &dso_debug_data[0], dynamic_length);
+
+    return true;
+  }
+
+  void set_minidump_size_limit(off_t limit) { minidump_size_limit_ = limit; }
+
+ private:
+  void* Alloc(unsigned bytes) {
+    return dumper_->allocator()->Alloc(bytes);
+  }
+
+  pid_t GetCrashThread() const {
+    return dumper_->crash_thread();
+  }
+
+  void NullifyDirectoryEntry(MDRawDirectory* dirent) {
+    dirent->stream_type = 0;
+    dirent->location.data_size = 0;
+    dirent->location.rva = 0;
+  }
+
+#if defined(__i386__) || defined(__x86_64__) || defined(__mips__)
+  bool WriteCPUInformation(MDRawSystemInfo* sys_info) {
+    char vendor_id[sizeof(sys_info->cpu.x86_cpu_info.vendor_id) + 1] = {0};
+    static const char vendor_id_name[] = "vendor_id";
+
+    struct CpuInfoEntry {
+      const char* info_name;
+      int value;
+      bool found;
+    } cpu_info_table[] = {
+      { "processor", -1, false },
+#if defined(__i386__) || defined(__x86_64__)
+      { "model", 0, false },
+      { "stepping",  0, false },
+      { "cpu family", 0, false },
+#endif
+    };
+
+    // processor_architecture should always be set, do this first
+    sys_info->processor_architecture =
+#if defined(__mips__)
+# if _MIPS_SIM == _ABIO32
+        MD_CPU_ARCHITECTURE_MIPS;
+# elif _MIPS_SIM == _ABI64
+        MD_CPU_ARCHITECTURE_MIPS64;
+# else
+#  error "This mips ABI is currently not supported (n32)"
+#endif
+#elif defined(__i386__)
+        MD_CPU_ARCHITECTURE_X86;
+#else
+        MD_CPU_ARCHITECTURE_AMD64;
+#endif
+
+    const int fd = sys_open("/proc/cpuinfo", O_RDONLY, 0);
+    if (fd < 0)
+      return false;
+
+    {
+      PageAllocator allocator;
+      ProcCpuInfoReader* const reader = new(allocator) ProcCpuInfoReader(fd);
+      const char* field;
+      while (reader->GetNextField(&field)) {
+        bool is_first_entry = true;
+        for (CpuInfoEntry& entry : cpu_info_table) {
+          if (!is_first_entry && entry.found) {
+            // except for the 'processor' field, ignore repeated values.
+            continue;
+          }
+          is_first_entry = false;
+          if (!my_strcmp(field, entry.info_name)) {
+            size_t value_len;
+            const char* value = reader->GetValueAndLen(&value_len);
+            if (value_len == 0)
+              continue;
+
+            uintptr_t val;
+            if (my_read_decimal_ptr(&val, value) == value)
+              continue;
+
+            entry.value = static_cast<int>(val);
+            entry.found = true;
+          }
+        }
+
+        // special case for vendor_id
+        if (!my_strcmp(field, vendor_id_name)) {
+          size_t value_len;
+          const char* value = reader->GetValueAndLen(&value_len);
+          if (value_len > 0)
+            my_strlcpy(vendor_id, value, sizeof(vendor_id));
+        }
+      }
+      sys_close(fd);
+    }
+
+    // make sure we got everything we wanted
+    for (const CpuInfoEntry& entry : cpu_info_table) {
+      if (!entry.found) {
+        return false;
+      }
+    }
+    // cpu_info_table[0] holds the last cpu id listed in /proc/cpuinfo,
+    // assuming this is the highest id, change it to the number of CPUs
+    // by adding one.
+    cpu_info_table[0].value++;
+
+    sys_info->number_of_processors = cpu_info_table[0].value;
+#if defined(__i386__) || defined(__x86_64__)
+    sys_info->processor_level      = cpu_info_table[3].value;
+    sys_info->processor_revision   = cpu_info_table[1].value << 8 |
+                                     cpu_info_table[2].value;
+#endif
+
+    if (vendor_id[0] != '\0') {
+      my_memcpy(sys_info->cpu.x86_cpu_info.vendor_id, vendor_id,
+                sizeof(sys_info->cpu.x86_cpu_info.vendor_id));
+    }
+    return true;
+  }
+#elif defined(__arm__) || defined(__aarch64__)
+  bool WriteCPUInformation(MDRawSystemInfo* sys_info) {
+    // The CPUID value is broken up in several entries in /proc/cpuinfo.
+    // This table is used to rebuild it from the entries.
+    const struct CpuIdEntry {
+      const char* field;
+      char        format;
+      char        bit_lshift;
+      char        bit_length;
+    } cpu_id_entries[] = {
+      { "CPU implementer", 'x', 24, 8 },
+      { "CPU variant", 'x', 20, 4 },
+      { "CPU part", 'x', 4, 12 },
+      { "CPU revision", 'd', 0, 4 },
+    };
+
+    // The ELF hwcaps are listed in the "Features" entry as textual tags.
+    // This table is used to rebuild them.
+    const struct CpuFeaturesEntry {
+      const char* tag;
+      uint32_t hwcaps;
+    } cpu_features_entries[] = {
+#if defined(__arm__)
+      { "swp",  MD_CPU_ARM_ELF_HWCAP_SWP },
+      { "half", MD_CPU_ARM_ELF_HWCAP_HALF },
+      { "thumb", MD_CPU_ARM_ELF_HWCAP_THUMB },
+      { "26bit", MD_CPU_ARM_ELF_HWCAP_26BIT },
+      { "fastmult", MD_CPU_ARM_ELF_HWCAP_FAST_MULT },
+      { "fpa", MD_CPU_ARM_ELF_HWCAP_FPA },
+      { "vfp", MD_CPU_ARM_ELF_HWCAP_VFP },
+      { "edsp", MD_CPU_ARM_ELF_HWCAP_EDSP },
+      { "java", MD_CPU_ARM_ELF_HWCAP_JAVA },
+      { "iwmmxt", MD_CPU_ARM_ELF_HWCAP_IWMMXT },
+      { "crunch", MD_CPU_ARM_ELF_HWCAP_CRUNCH },
+      { "thumbee", MD_CPU_ARM_ELF_HWCAP_THUMBEE },
+      { "neon", MD_CPU_ARM_ELF_HWCAP_NEON },
+      { "vfpv3", MD_CPU_ARM_ELF_HWCAP_VFPv3 },
+      { "vfpv3d16", MD_CPU_ARM_ELF_HWCAP_VFPv3D16 },
+      { "tls", MD_CPU_ARM_ELF_HWCAP_TLS },
+      { "vfpv4", MD_CPU_ARM_ELF_HWCAP_VFPv4 },
+      { "idiva", MD_CPU_ARM_ELF_HWCAP_IDIVA },
+      { "idivt", MD_CPU_ARM_ELF_HWCAP_IDIVT },
+      { "idiv", MD_CPU_ARM_ELF_HWCAP_IDIVA | MD_CPU_ARM_ELF_HWCAP_IDIVT },
+#elif defined(__aarch64__)
+      // No hwcaps on aarch64.
+#endif
+    };
+
+    // processor_architecture should always be set, do this first
+    sys_info->processor_architecture =
+#if defined(__aarch64__)
+        MD_CPU_ARCHITECTURE_ARM64_OLD;
+#else
+        MD_CPU_ARCHITECTURE_ARM;
+#endif
+
+    // /proc/cpuinfo is not readable under various sandboxed environments
+    // (e.g. Android services with the android:isolatedProcess attribute)
+    // prepare for this by setting default values now, which will be
+    // returned when this happens.
+    //
+    // Note: Bogus values are used to distinguish between failures (to
+    //       read /sys and /proc files) and really badly configured kernels.
+    sys_info->number_of_processors = 0;
+    sys_info->processor_level = 1U;  // There is no ARMv1
+    sys_info->processor_revision = 42;
+    sys_info->cpu.arm_cpu_info.cpuid = 0;
+    sys_info->cpu.arm_cpu_info.elf_hwcaps = 0;
+
+    // Counting the number of CPUs involves parsing two sysfs files,
+    // because the content of /proc/cpuinfo will only mirror the number
+    // of 'online' cores, and thus will vary with time.
+    // See http://www.kernel.org/doc/Documentation/cputopology.txt
+    {
+      CpuSet cpus_present;
+      CpuSet cpus_possible;
+
+      int fd = sys_open("/sys/devices/system/cpu/present", O_RDONLY, 0);
+      if (fd >= 0) {
+        cpus_present.ParseSysFile(fd);
+        sys_close(fd);
+
+        fd = sys_open("/sys/devices/system/cpu/possible", O_RDONLY, 0);
+        if (fd >= 0) {
+          cpus_possible.ParseSysFile(fd);
+          sys_close(fd);
+
+          cpus_present.IntersectWith(cpus_possible);
+          int cpu_count = cpus_present.GetCount();
+          if (cpu_count > 255)
+            cpu_count = 255;
+          sys_info->number_of_processors = static_cast<uint8_t>(cpu_count);
+        }
+      }
+    }
+
+    // Parse /proc/cpuinfo to reconstruct the CPUID value, as well
+    // as the ELF hwcaps field. For the latter, it would be easier to
+    // read /proc/self/auxv but unfortunately, this file is not always
+    // readable from regular Android applications on later versions
+    // (>= 4.1) of the Android platform.
+    const int fd = sys_open("/proc/cpuinfo", O_RDONLY, 0);
+    if (fd < 0) {
+      // Do not return false here to allow the minidump generation
+      // to happen properly.
+      return true;
+    }
+
+    {
+      PageAllocator allocator;
+      ProcCpuInfoReader* const reader =
+          new(allocator) ProcCpuInfoReader(fd);
+      const char* field;
+      while (reader->GetNextField(&field)) {
+        for (const CpuIdEntry& entry : cpu_id_entries) {
+          if (my_strcmp(entry.field, field) != 0)
+            continue;
+          uintptr_t result = 0;
+          const char* value = reader->GetValue();
+          const char* p = value;
+          if (value[0] == '0' && value[1] == 'x') {
+            p = my_read_hex_ptr(&result, value+2);
+          } else if (entry.format == 'x') {
+            p = my_read_hex_ptr(&result, value);
+          } else {
+            p = my_read_decimal_ptr(&result, value);
+          }
+          if (p == value)
+            continue;
+
+          result &= (1U << entry.bit_length)-1;
+          result <<= entry.bit_lshift;
+          sys_info->cpu.arm_cpu_info.cpuid |=
+              static_cast<uint32_t>(result);
+        }
+#if defined(__arm__)
+        // Get the architecture version from the "Processor" field.
+        // Note that it is also available in the "CPU architecture" field,
+        // however, some existing kernels are misconfigured and will report
+        // invalid values here (e.g. 6, while the CPU is ARMv7-A based).
+        // The "Processor" field doesn't have this issue.
+        if (!my_strcmp(field, "Processor")) {
+          size_t value_len;
+          const char* value = reader->GetValueAndLen(&value_len);
+          // Expected format: <text> (v<level><endian>)
+          // Where <text> is some text like "ARMv7 Processor rev 2"
+          // and <level> is a decimal corresponding to the ARM
+          // architecture number. <endian> is either 'l' or 'b'
+          // and corresponds to the endianess, it is ignored here.
+          while (value_len > 0 && my_isspace(value[value_len-1]))
+            value_len--;
+
+          size_t nn = value_len;
+          while (nn > 0 && value[nn-1] != '(')
+            nn--;
+          if (nn > 0 && value[nn] == 'v') {
+            uintptr_t arch_level = 5;
+            my_read_decimal_ptr(&arch_level, value + nn + 1);
+            sys_info->processor_level = static_cast<uint16_t>(arch_level);
+          }
+        }
+#elif defined(__aarch64__)
+        // The aarch64 architecture does not provide the architecture level
+        // in the Processor field, so we instead check the "CPU architecture"
+        // field.
+        if (!my_strcmp(field, "CPU architecture")) {
+          uintptr_t arch_level = 0;
+          const char* value = reader->GetValue();
+          const char* p = value;
+          p = my_read_decimal_ptr(&arch_level, value);
+          if (p == value)
+            continue;
+          sys_info->processor_level = static_cast<uint16_t>(arch_level);
+        }
+#endif
+        // Rebuild the ELF hwcaps from the 'Features' field.
+        if (!my_strcmp(field, "Features")) {
+          size_t value_len;
+          const char* value = reader->GetValueAndLen(&value_len);
+
+          // Parse each space-separated tag.
+          while (value_len > 0) {
+            const char* tag = value;
+            size_t tag_len = value_len;
+            const char* p = my_strchr(tag, ' ');
+            if (p) {
+              tag_len = static_cast<size_t>(p - tag);
+              value += tag_len + 1;
+              value_len -= tag_len + 1;
+            } else {
+              tag_len = strlen(tag);
+              value_len = 0;
+            }
+            for (const CpuFeaturesEntry& entry : cpu_features_entries) {
+              if (tag_len == strlen(entry.tag) &&
+                  !memcmp(tag, entry.tag, tag_len)) {
+                sys_info->cpu.arm_cpu_info.elf_hwcaps |= entry.hwcaps;
+                break;
+              }
+            }
+          }
+        }
+      }
+      sys_close(fd);
+    }
+
+    return true;
+  }
+#else
+#  error "Unsupported CPU"
+#endif
+
+  bool WriteFile(MDLocationDescriptor* result, const char* filename) {
+    const int fd = sys_open(filename, O_RDONLY, 0);
+    if (fd < 0)
+      return false;
+
+    // We can't stat the files because several of the files that we want to
+    // read are kernel seqfiles, which always have a length of zero. So we have
+    // to read as much as we can into a buffer.
+    static const unsigned kBufSize = 1024 - 2*sizeof(void*);
+    struct Buffers {
+      Buffers* next;
+      size_t len;
+      uint8_t data[kBufSize];
+    } *buffers = reinterpret_cast<Buffers*>(Alloc(sizeof(Buffers)));
+    buffers->next = NULL;
+    buffers->len = 0;
+
+    size_t total = 0;
+    for (Buffers* bufptr = buffers;;) {
+      ssize_t r;
+      do {
+        r = sys_read(fd, &bufptr->data[bufptr->len], kBufSize - bufptr->len);
+      } while (r == -1 && errno == EINTR);
+
+      if (r < 1)
+        break;
+
+      total += r;
+      bufptr->len += r;
+      if (bufptr->len == kBufSize) {
+        bufptr->next = reinterpret_cast<Buffers*>(Alloc(sizeof(Buffers)));
+        bufptr = bufptr->next;
+        bufptr->next = NULL;
+        bufptr->len = 0;
+      }
+    }
+    sys_close(fd);
+
+    if (!total)
+      return false;
+
+    UntypedMDRVA memory(&minidump_writer_);
+    if (!memory.Allocate(total))
+      return false;
+    for (MDRVA pos = memory.position(); buffers; buffers = buffers->next) {
+      // Check for special case of a zero-length buffer.  This should only
+      // occur if a file's size happens to be a multiple of the buffer's
+      // size, in which case the final sys_read() will have resulted in
+      // zero bytes being read after the final buffer was just allocated.
+      if (buffers->len == 0) {
+        // This can only occur with final buffer.
+        assert(buffers->next == NULL);
+        continue;
+      }
+      memory.Copy(pos, &buffers->data, buffers->len);
+      pos += buffers->len;
+    }
+    *result = memory.location();
+    return true;
+  }
+
+  bool WriteOSInformation(MDRawSystemInfo* sys_info) {
+#if defined(__ANDROID__)
+    sys_info->platform_id = MD_OS_ANDROID;
+#else
+    sys_info->platform_id = MD_OS_LINUX;
+#endif
+
+    struct utsname uts;
+    if (uname(&uts))
+      return false;
+
+    static const size_t buf_len = 512;
+    char buf[buf_len] = {0};
+    size_t space_left = buf_len - 1;
+    const char* info_table[] = {
+      uts.sysname,
+      uts.release,
+      uts.version,
+      uts.machine,
+      NULL
+    };
+    bool first_item = true;
+    for (const char** cur_info = info_table; *cur_info; cur_info++) {
+      static const char separator[] = " ";
+      size_t separator_len = sizeof(separator) - 1;
+      size_t info_len = my_strlen(*cur_info);
+      if (info_len == 0)
+        continue;
+
+      if (space_left < info_len + (first_item ? 0 : separator_len))
+        break;
+
+      if (!first_item) {
+        my_strlcat(buf, separator, sizeof(buf));
+        space_left -= separator_len;
+      }
+
+      first_item = false;
+      my_strlcat(buf, *cur_info, sizeof(buf));
+      space_left -= info_len;
+    }
+
+    MDLocationDescriptor location;
+    if (!minidump_writer_.WriteString(buf, 0, &location))
+      return false;
+    sys_info->csd_version_rva = location.rva;
+
+    return true;
+  }
+
+  bool WriteProcFile(MDLocationDescriptor* result, pid_t pid,
+                     const char* filename) {
+    char buf[NAME_MAX];
+    if (!dumper_->BuildProcPath(buf, pid, filename))
+      return false;
+    return WriteFile(result, buf);
+  }
+
+  // Only one of the 2 member variables below should be set to a valid value.
+  const int fd_;  // File descriptor where the minidum should be written.
+  const char* path_;  // Path to the file where the minidum should be written.
+
+  const ucontext_t* const ucontext_;  // also from the signal handler
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+  const google_breakpad::fpstate_t* const float_state_;  // ditto
+#endif
+  LinuxDumper* dumper_;
+  MinidumpFileWriter minidump_writer_;
+  off_t minidump_size_limit_;
+  MDLocationDescriptor crashing_thread_context_;
+  // Blocks of memory written to the dump. These are all currently
+  // written while writing the thread list stream, but saved here
+  // so a memory list stream can be written afterwards.
+  wasteful_vector<MDMemoryDescriptor> memory_blocks_;
+  // Additional information about some mappings provided by the caller.
+  const MappingList& mapping_list_;
+  // Additional memory regions to be included in the dump,
+  // provided by the caller.
+  const AppMemoryList& app_memory_list_;
+  // If set, skip recording any threads that do not reference the
+  // mapping containing principal_mapping_address_.
+  bool skip_stacks_if_mapping_unreferenced_;
+  uintptr_t principal_mapping_address_;
+  const MappingInfo* principal_mapping_;
+  // If true, apply stack sanitization to stored stack data.
+  bool sanitize_stacks_;
+};
+
+
+bool WriteMinidumpImpl(const char* minidump_path,
+                       int minidump_fd,
+                       off_t minidump_size_limit,
+                       pid_t crashing_process,
+                       const void* blob, size_t blob_size,
+                       const MappingList& mappings,
+                       const AppMemoryList& appmem,
+                       bool skip_stacks_if_mapping_unreferenced,
+                       uintptr_t principal_mapping_address,
+                       bool sanitize_stacks) {
+  LinuxPtraceDumper dumper(crashing_process);
+  const ExceptionHandler::CrashContext* context = NULL;
+  if (blob) {
+    if (blob_size != sizeof(ExceptionHandler::CrashContext))
+      return false;
+    context = reinterpret_cast<const ExceptionHandler::CrashContext*>(blob);
+    dumper.SetCrashInfoFromSigInfo(context->siginfo);
+    dumper.set_crash_thread(context->tid);
+  }
+  MinidumpWriter writer(minidump_path, minidump_fd, context, mappings,
+                        appmem, skip_stacks_if_mapping_unreferenced,
+                        principal_mapping_address, sanitize_stacks, &dumper);
+  // Set desired limit for file size of minidump (-1 means no limit).
+  writer.set_minidump_size_limit(minidump_size_limit);
+  if (!writer.Init())
+    return false;
+  return writer.Dump();
+}
+
+}  // namespace
+
+namespace google_breakpad {
+
+bool WriteMinidump(const char* minidump_path, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   bool skip_stacks_if_mapping_unreferenced,
+                   uintptr_t principal_mapping_address,
+                   bool sanitize_stacks) {
+  return WriteMinidumpImpl(minidump_path, -1, -1,
+                           crashing_process, blob, blob_size,
+                           MappingList(), AppMemoryList(),
+                           skip_stacks_if_mapping_unreferenced,
+                           principal_mapping_address,
+                           sanitize_stacks);
+}
+
+bool WriteMinidump(int minidump_fd, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   bool skip_stacks_if_mapping_unreferenced,
+                   uintptr_t principal_mapping_address,
+                   bool sanitize_stacks) {
+  return WriteMinidumpImpl(NULL, minidump_fd, -1,
+                           crashing_process, blob, blob_size,
+                           MappingList(), AppMemoryList(),
+                           skip_stacks_if_mapping_unreferenced,
+                           principal_mapping_address,
+                           sanitize_stacks);
+}
+
+bool WriteMinidump(const char* minidump_path, pid_t process,
+                   pid_t process_blamed_thread) {
+  LinuxPtraceDumper dumper(process);
+  // MinidumpWriter will set crash address
+  dumper.set_crash_signal(MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED);
+  dumper.set_crash_thread(process_blamed_thread);
+  MappingList mapping_list;
+  AppMemoryList app_memory_list;
+  MinidumpWriter writer(minidump_path, -1, NULL, mapping_list,
+                        app_memory_list, false, 0, false, &dumper);
+  if (!writer.Init())
+    return false;
+  return writer.Dump();
+}
+
+bool WriteMinidump(const char* minidump_path, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appmem,
+                   bool skip_stacks_if_mapping_unreferenced,
+                   uintptr_t principal_mapping_address,
+                   bool sanitize_stacks) {
+  return WriteMinidumpImpl(minidump_path, -1, -1, crashing_process,
+                           blob, blob_size,
+                           mappings, appmem,
+                           skip_stacks_if_mapping_unreferenced,
+                           principal_mapping_address,
+                           sanitize_stacks);
+}
+
+bool WriteMinidump(int minidump_fd, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appmem,
+                   bool skip_stacks_if_mapping_unreferenced,
+                   uintptr_t principal_mapping_address,
+                   bool sanitize_stacks) {
+  return WriteMinidumpImpl(NULL, minidump_fd, -1, crashing_process,
+                           blob, blob_size,
+                           mappings, appmem,
+                           skip_stacks_if_mapping_unreferenced,
+                           principal_mapping_address,
+                           sanitize_stacks);
+}
+
+bool WriteMinidump(const char* minidump_path, off_t minidump_size_limit,
+                   pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appmem,
+                   bool skip_stacks_if_mapping_unreferenced,
+                   uintptr_t principal_mapping_address,
+                   bool sanitize_stacks) {
+  return WriteMinidumpImpl(minidump_path, -1, minidump_size_limit,
+                           crashing_process, blob, blob_size,
+                           mappings, appmem,
+                           skip_stacks_if_mapping_unreferenced,
+                           principal_mapping_address,
+                           sanitize_stacks);
+}
+
+bool WriteMinidump(int minidump_fd, off_t minidump_size_limit,
+                   pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appmem,
+                   bool skip_stacks_if_mapping_unreferenced,
+                   uintptr_t principal_mapping_address,
+                   bool sanitize_stacks) {
+  return WriteMinidumpImpl(NULL, minidump_fd, minidump_size_limit,
+                           crashing_process, blob, blob_size,
+                           mappings, appmem,
+                           skip_stacks_if_mapping_unreferenced,
+                           principal_mapping_address,
+                           sanitize_stacks);
+}
+
+bool WriteMinidump(const char* filename,
+                   const MappingList& mappings,
+                   const AppMemoryList& appmem,
+                   LinuxDumper* dumper) {
+  MinidumpWriter writer(filename, -1, NULL, mappings, appmem,
+                        false, 0, false, dumper);
+  if (!writer.Init())
+    return false;
+  return writer.Dump();
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer.h
new file mode 100644
index 0000000000..1d02ec8d7d
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer.h
@@ -0,0 +1,143 @@
+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_H_
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/ucontext.h>
+#include <unistd.h>
+
+#include <list>
+#include <type_traits>
+#include <utility>
+
+#include "linux/minidump_writer/linux_dumper.h"
+#include "google_breakpad/common/minidump_format.h"
+
+namespace google_breakpad {
+
+class ExceptionHandler;
+
+#if defined(__aarch64__)
+typedef struct fpsimd_context fpstate_t;
+#elif !defined(__ARM_EABI__) && !defined(__mips__)
+typedef std::remove_pointer<fpregset_t>::type fpstate_t;
+#endif
+
+// These entries store a list of memory regions that the client wants included
+// in the minidump.
+struct AppMemory {
+  void* ptr;
+  size_t length;
+
+  bool operator==(const struct AppMemory& other) const {
+    return ptr == other.ptr;
+  }
+
+  bool operator==(const void* other) const {
+    return ptr == other;
+  }
+};
+typedef std::list<AppMemory> AppMemoryList;
+
+// Writes a minidump to the filesystem. These functions do not malloc nor use
+// libc functions which may. Thus, it can be used in contexts where the state
+// of the heap may be corrupt.
+//   minidump_path: the path to the file to write to. This is opened O_EXCL and
+//     fails open fails.
+//   crashing_process: the pid of the crashing process. This must be trusted.
+//   blob: a blob of data from the crashing process. See exception_handler.h
+//   blob_size: the length of |blob|, in bytes
+//
+// Returns true iff successful.
+bool WriteMinidump(const char* minidump_path, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   bool skip_stacks_if_mapping_unreferenced = false,
+                   uintptr_t principal_mapping_address = 0,
+                   bool sanitize_stacks = false);
+// Same as above but takes an open file descriptor instead of a path.
+bool WriteMinidump(int minidump_fd, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   bool skip_stacks_if_mapping_unreferenced = false,
+                   uintptr_t principal_mapping_address = 0,
+                   bool sanitize_stacks = false);
+
+// Alternate form of WriteMinidump() that works with processes that
+// are not expected to have crashed.  If |process_blamed_thread| is
+// meaningful, it will be the one from which a crash signature is
+// extracted.  It is not expected that this function will be called
+// from a compromised context, but it is safe to do so.
+bool WriteMinidump(const char* minidump_path, pid_t process,
+                   pid_t process_blamed_thread);
+
+// These overloads also allow passing a list of known mappings and
+// a list of additional memory regions to be included in the minidump.
+bool WriteMinidump(const char* minidump_path, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appdata,
+                   bool skip_stacks_if_mapping_unreferenced = false,
+                   uintptr_t principal_mapping_address = 0,
+                   bool sanitize_stacks = false);
+bool WriteMinidump(int minidump_fd, pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appdata,
+                   bool skip_stacks_if_mapping_unreferenced = false,
+                   uintptr_t principal_mapping_address = 0,
+                   bool sanitize_stacks = false);
+
+// These overloads also allow passing a file size limit for the minidump.
+bool WriteMinidump(const char* minidump_path, off_t minidump_size_limit,
+                   pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appdata,
+                   bool skip_stacks_if_mapping_unreferenced = false,
+                   uintptr_t principal_mapping_address = 0,
+                   bool sanitize_stacks = false);
+bool WriteMinidump(int minidump_fd, off_t minidump_size_limit,
+                   pid_t crashing_process,
+                   const void* blob, size_t blob_size,
+                   const MappingList& mappings,
+                   const AppMemoryList& appdata,
+                   bool skip_stacks_if_mapping_unreferenced = false,
+                   uintptr_t principal_mapping_address = 0,
+                   bool sanitize_stacks = false);
+
+bool WriteMinidump(const char* filename,
+                   const MappingList& mappings,
+                   const AppMemoryList& appdata,
+                   LinuxDumper* dumper);
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest.cc
new file mode 100644
index 0000000000..4e49a4e577
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest.cc
@@ -0,0 +1,934 @@
+// Copyright (c) 2011 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <fcntl.h>
+#include <poll.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+#include <string>
+
+#include "breakpad_googletest_includes.h"
+#include "linux/handler/exception_handler.h"
+#include "linux/minidump_writer/linux_dumper.h"
+#include "linux/minidump_writer/minidump_writer.h"
+#include "linux/minidump_writer/minidump_writer_unittest_utils.h"
+#include "common/linux/breakpad_getcontext.h"
+#include "common/linux/eintr_wrapper.h"
+#include "common/linux/file_id.h"
+#include "common/linux/ignore_ret.h"
+#include "common/linux/safe_readlink.h"
+#include "common/scoped_ptr.h"
+#include "common/tests/auto_tempdir.h"
+#include "common/tests/file_utils.h"
+#include "common/using_std_string.h"
+#include "google_breakpad/processor/minidump.h"
+
+using namespace google_breakpad;
+
+namespace {
+
+typedef testing::Test MinidumpWriterTest;
+
+const char kMDWriterUnitTestFileName[] = "/minidump-writer-unittest";
+
+TEST(MinidumpWriterTest, SetupWithPath) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+  // Set a non-zero tid to avoid tripping asserts.
+  context.tid = child;
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context)));
+  struct stat st;
+  ASSERT_EQ(0, stat(templ.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+TEST(MinidumpWriterTest, SetupWithFD) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+  int fd = open(templ.c_str(), O_CREAT | O_WRONLY, S_IRWXU);
+  // Set a non-zero tid to avoid tripping asserts.
+  context.tid = child;
+  ASSERT_TRUE(WriteMinidump(fd, child, &context, sizeof(context)));
+  struct stat st;
+  ASSERT_EQ(0, stat(templ.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that mapping info can be specified when writing a minidump,
+// and that it ends up in the module list of the minidump.
+TEST(MinidumpWriterTest, MappingInfo) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const uint32_t memory_size = sysconf(_SC_PAGESIZE);
+  const char* kMemoryName = "a fake module";
+  const uint8_t kModuleGUID[sizeof(MDGUID)] = {
+    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+    0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
+  };
+  const string module_identifier = "33221100554477668899AABBCCDDEEFF0";
+
+  // Get some memory.
+  char* memory =
+    reinterpret_cast<char*>(mmap(NULL,
+                                 memory_size,
+                                 PROT_READ | PROT_WRITE,
+                                 MAP_PRIVATE | MAP_ANON,
+                                 -1,
+                                 0));
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+
+  // Add information about the mapped memory.
+  MappingInfo info;
+  info.start_addr = kMemoryAddress;
+  info.size = memory_size;
+  info.offset = 0;
+  info.exec = false;
+  strcpy(info.name, kMemoryName);
+
+  MappingList mappings;
+  AppMemoryList memory_list;
+  MappingEntry mapping;
+  mapping.first = info;
+  mapping.second.assign(std::begin(kModuleGUID), std::end(kModuleGUID));
+  mappings.push_back(mapping);
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
+                            mappings, memory_list, false, 0, false));
+
+  // Read the minidump. Load the module list, and ensure that
+  // the mmap'ed |memory| is listed with the given module name
+  // and debug ID.
+  Minidump minidump(templ);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpModuleList* module_list = minidump.GetModuleList();
+  ASSERT_TRUE(module_list);
+  const MinidumpModule* module =
+    module_list->GetModuleForAddress(kMemoryAddress);
+  ASSERT_TRUE(module);
+
+  EXPECT_EQ(kMemoryAddress, module->base_address());
+  EXPECT_EQ(memory_size, module->size());
+  EXPECT_EQ(kMemoryName, module->code_file());
+  EXPECT_EQ(module_identifier, module->debug_identifier());
+
+  uint32_t len;
+  // These streams are expected to be there
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_THREAD_LIST_STREAM, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_MEMORY_LIST_STREAM, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_EXCEPTION_STREAM, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_SYSTEM_INFO_STREAM, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_CPU_INFO, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_PROC_STATUS, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_CMD_LINE, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_ENVIRON, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_AUXV, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_MAPS, &len));
+  EXPECT_TRUE(minidump.SeekToStreamType(MD_LINUX_DSO_DEBUG, &len));
+
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that minidumping is skipped while writing minidumps if principal mapping
+// is not referenced.
+TEST(MinidumpWriterTest, MinidumpSkippedIfRequested) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+
+  // pass an invalid principal mapping address, which will force
+  // WriteMinidump to not write a minidump.
+  ASSERT_FALSE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
+                            true, static_cast<uintptr_t>(0x0102030405060708ull),
+                            false));
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that minidumping is skipped while writing minidumps if principal mapping
+// is not referenced.
+TEST(MinidumpWriterTest, MinidumpStacksSkippedIfRequested) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+
+    // Create a thread that does not return, and only references libc (not the
+    // current executable). This thread should not be captured in the minidump.
+    pthread_t thread;
+    pthread_attr_t thread_attributes;
+    pthread_attr_init(&thread_attributes);
+    pthread_attr_setdetachstate(&thread_attributes, PTHREAD_CREATE_DETACHED);
+    sigset_t sigset;
+    sigemptyset(&sigset);
+    pthread_create(&thread, &thread_attributes,
+                   reinterpret_cast<void* (*)(void*)>(&sigsuspend), &sigset);
+
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+
+  // Pass an invalid principal mapping address, which will force
+  // WriteMinidump to not dump any thread stacks.
+  ASSERT_TRUE(WriteMinidump(
+      templ.c_str(), child, &context, sizeof(context), true,
+      reinterpret_cast<uintptr_t>(google_breakpad::WriteFile), false));
+
+  // Read the minidump. And ensure that thread memory was dumped only for the
+  // main thread.
+  Minidump minidump(templ);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpThreadList *threads = minidump.GetThreadList();
+  int threads_with_stacks = 0;
+  for (unsigned int i = 0; i < threads->thread_count(); ++i) {
+    MinidumpThread *thread = threads->GetThreadAtIndex(i);
+    if (thread->GetMemory()) {
+      ++threads_with_stacks;
+    }
+  }
+#if defined(THREAD_SANITIZER) || defined(ADDRESS_SANITIZER)
+  ASSERT_GE(threads_with_stacks, 1);
+#else
+  ASSERT_EQ(threads_with_stacks, 1);
+#endif
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that stacks can be sanitized while writing minidumps.
+TEST(MinidumpWriterTest, StacksAreSanitizedIfRequested) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+  // pass an invalid principal mapping address, which will force
+  // WriteMinidump to not dump any thread stacks.
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
+                            false, 0, true));
+
+  // Read the minidump. And ensure that thread memory contains a defaced value.
+  Minidump minidump(templ);
+  ASSERT_TRUE(minidump.Read());
+
+  const uintptr_t defaced =
+#if defined(__LP64__)
+      0x0defaced0defaced;
+#else
+      0x0defaced;
+#endif
+  MinidumpThreadList *threads = minidump.GetThreadList();
+  for (unsigned int i = 0; i < threads->thread_count(); ++i) {
+    MinidumpThread *thread = threads->GetThreadAtIndex(i);
+    MinidumpMemoryRegion *mem = thread->GetMemory();
+    ASSERT_TRUE(mem != nullptr);
+    uint32_t sz = mem->GetSize();
+    const uint8_t *data = mem->GetMemory();
+    ASSERT_TRUE(memmem(data, sz, &defaced, sizeof(defaced)) != nullptr);
+  }
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that a binary with a longer-than-usual build id note
+// makes its way all the way through to the minidump unscathed.
+// The linux_client_unittest is linked with an explicit --build-id
+// in Makefile.am.
+TEST(MinidumpWriterTest, BuildIDLong) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  const string dump_path = temp_dir.path() + kMDWriterUnitTestFileName;
+
+  EXPECT_TRUE(WriteMinidump(dump_path.c_str(),
+                            child, &context, sizeof(context)));
+  close(fds[1]);
+
+  // Read the minidump. Load the module list, and ensure that
+  // the main module has the correct debug id and code id.
+  Minidump minidump(dump_path);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpModuleList* module_list = minidump.GetModuleList();
+  ASSERT_TRUE(module_list);
+  const MinidumpModule* module = module_list->GetMainModule();
+  ASSERT_TRUE(module);
+  const string module_identifier = "030201000504070608090A0B0C0D0E0F0";
+  // This is passed explicitly to the linker in Makefile.am
+  const string build_id =
+      "000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f";
+  EXPECT_EQ(module_identifier, module->debug_identifier());
+  EXPECT_EQ(build_id, module->code_identifier());
+
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that mapping info can be specified, and that it overrides
+// existing mappings that are wholly contained within the specified
+// range.
+TEST(MinidumpWriterTest, MappingInfoContained) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const int32_t memory_size = sysconf(_SC_PAGESIZE);
+  const char* kMemoryName = "a fake module";
+  const uint8_t kModuleGUID[sizeof(MDGUID)] = {
+    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+    0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
+  };
+  const string module_identifier = "33221100554477668899AABBCCDDEEFF0";
+
+  // mmap a file
+  AutoTempDir temp_dir;
+  string tempfile = temp_dir.path() + "/minidump-writer-unittest-temp";
+  int fd = open(tempfile.c_str(), O_RDWR | O_CREAT, 0);
+  ASSERT_NE(-1, fd);
+  unlink(tempfile.c_str());
+  // fill with zeros
+  google_breakpad::scoped_array<char> buffer(new char[memory_size]);
+  memset(buffer.get(), 0, memory_size);
+  ASSERT_EQ(memory_size, write(fd, buffer.get(), memory_size));
+  lseek(fd, 0, SEEK_SET);
+
+  char* memory =
+    reinterpret_cast<char*>(mmap(NULL,
+                                 memory_size,
+                                 PROT_READ | PROT_WRITE,
+                                 MAP_PRIVATE,
+                                 fd,
+                                 0));
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+  close(fd);
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  context.tid = 1;
+
+  string dumpfile = temp_dir.path() + kMDWriterUnitTestFileName;
+
+  // Add information about the mapped memory. Report it as being larger than
+  // it actually is.
+  MappingInfo info;
+  info.start_addr = kMemoryAddress - memory_size;
+  info.size = memory_size * 3;
+  info.offset = 0;
+  info.exec = false;
+  strcpy(info.name, kMemoryName);
+
+  MappingList mappings;
+  AppMemoryList memory_list;
+  MappingEntry mapping;
+  mapping.first = info;
+  mapping.second.assign(std::begin(kModuleGUID), std::end(kModuleGUID));
+  mappings.push_back(mapping);
+  ASSERT_TRUE(WriteMinidump(dumpfile.c_str(), child, &context, sizeof(context),
+                            mappings, memory_list));
+
+  // Read the minidump. Load the module list, and ensure that
+  // the mmap'ed |memory| is listed with the given module name
+  // and debug ID.
+  Minidump minidump(dumpfile);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpModuleList* module_list = minidump.GetModuleList();
+  ASSERT_TRUE(module_list);
+  const MinidumpModule* module =
+    module_list->GetModuleForAddress(kMemoryAddress);
+  ASSERT_TRUE(module);
+
+  EXPECT_EQ(info.start_addr, module->base_address());
+  EXPECT_EQ(info.size, module->size());
+  EXPECT_EQ(kMemoryName, module->code_file());
+  EXPECT_EQ(module_identifier, module->debug_identifier());
+
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+TEST(MinidumpWriterTest, DeletedBinary) {
+  const string kNumberOfThreadsArgument = "1";
+  const string helper_path(GetHelperBinary());
+  if (helper_path.empty()) {
+    FAIL() << "Couldn't find helper binary";
+    exit(1);
+  }
+
+  // Copy binary to a temp file.
+  AutoTempDir temp_dir;
+  string binpath = temp_dir.path() + "/linux-dumper-unittest-helper";
+  ASSERT_TRUE(CopyFile(helper_path.c_str(), binpath.c_str()))
+      << "Failed to copy " << helper_path << " to " << binpath;
+  ASSERT_EQ(0, chmod(binpath.c_str(), 0755));
+
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  pid_t child_pid = fork();
+  if (child_pid == 0) {
+    // In child process.
+    close(fds[0]);
+
+    // Pass the pipe fd and the number of threads as arguments.
+    char pipe_fd_string[8];
+    sprintf(pipe_fd_string, "%d", fds[1]);
+    execl(binpath.c_str(),
+          binpath.c_str(),
+          pipe_fd_string,
+          kNumberOfThreadsArgument.c_str(),
+          NULL);
+  }
+  close(fds[1]);
+  // Wait for the child process to signal that it's ready.
+  struct pollfd pfd;
+  memset(&pfd, 0, sizeof(pfd));
+  pfd.fd = fds[0];
+  pfd.events = POLLIN | POLLERR;
+
+  const int r = HANDLE_EINTR(poll(&pfd, 1, 1000));
+  ASSERT_EQ(1, r);
+  ASSERT_TRUE(pfd.revents & POLLIN);
+  uint8_t junk;
+  const int nr = HANDLE_EINTR(read(fds[0], &junk, sizeof(junk)));
+  ASSERT_EQ(static_cast<ssize_t>(sizeof(junk)), nr);
+  close(fds[0]);
+
+  // Child is ready now.
+  // Unlink the test binary.
+  unlink(binpath.c_str());
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+  // Set a non-zero tid to avoid tripping asserts.
+  context.tid = child_pid;
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child_pid, &context,
+                            sizeof(context)));
+  kill(child_pid, SIGKILL);
+
+  struct stat st;
+  ASSERT_EQ(0, stat(templ.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  Minidump minidump(templ);
+  ASSERT_TRUE(minidump.Read());
+
+  // Check that the main module filename is correct.
+  MinidumpModuleList* module_list = minidump.GetModuleList();
+  ASSERT_TRUE(module_list);
+  const MinidumpModule* module = module_list->GetMainModule();
+  EXPECT_STREQ(binpath.c_str(), module->code_file().c_str());
+  // Check that the file ID is correct.
+  FileID fileid(helper_path.c_str());
+  PageAllocator allocator;
+  wasteful_vector<uint8_t> identifier(&allocator, kDefaultBuildIdSize);
+  EXPECT_TRUE(fileid.ElfFileIdentifier(identifier));
+  string identifier_string = FileID::ConvertIdentifierToUUIDString(identifier);
+  string module_identifier(identifier_string);
+  // Strip out dashes
+  size_t pos;
+  while ((pos = module_identifier.find('-')) != string::npos) {
+    module_identifier.erase(pos, 1);
+  }
+  // And append a zero, because module IDs include an "age" field
+  // which is always zero on Linux.
+  module_identifier += "0";
+  EXPECT_EQ(module_identifier, module->debug_identifier());
+
+  IGNORE_EINTR(waitpid(child_pid, nullptr, 0));
+}
+
+// Test that an additional memory region can be added to the minidump.
+TEST(MinidumpWriterTest, AdditionalMemory) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const uint32_t kMemorySize = sysconf(_SC_PAGESIZE);
+
+  // Get some heap memory.
+  uint8_t* memory = new uint8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  // Stick some data into the memory so the contents can be verified.
+  for (uint32_t i = 0; i < kMemorySize; ++i) {
+    memory[i] = i % 255;
+  }
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+
+  // This needs a valid context for minidump writing to work, but getting
+  // a useful one from the child is too much work, so just use one from
+  // the parent since the child is just a forked copy anyway.
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+  unlink(templ.c_str());
+
+  MappingList mappings;
+  AppMemoryList memory_list;
+
+  // Add the memory region to the list of memory to be included.
+  AppMemory app_memory;
+  app_memory.ptr = memory;
+  app_memory.length = kMemorySize;
+  memory_list.push_back(app_memory);
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context),
+                            mappings, memory_list));
+
+  // Read the minidump. Ensure that the memory region is present
+  Minidump minidump(templ);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemoryAddress, region->GetBase());
+  EXPECT_EQ(kMemorySize, region->GetSize());
+
+  // Verify memory contents.
+  EXPECT_EQ(0, memcmp(region->GetMemory(), memory, kMemorySize));
+
+  delete[] memory;
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that an invalid thread stack pointer still results in a minidump.
+TEST(MinidumpWriterTest, InvalidStackPointer) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    close(fds[0]);
+    syscall(__NR_exit_group);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+
+  // This needs a valid context for minidump writing to work, but getting
+  // a useful one from the child is too much work, so just use one from
+  // the parent since the child is just a forked copy anyway.
+  ASSERT_EQ(0, getcontext(&context.context));
+  context.tid = child;
+
+  // Fake the child's stack pointer for its crashing thread.  NOTE: This must
+  // be an invalid memory address for the child process (stack or otherwise).
+  // Try 1MB below the current stack.
+  uintptr_t invalid_stack_pointer =
+      reinterpret_cast<uintptr_t>(&context) - 1024*1024;
+#if defined(__i386)
+  context.context.uc_mcontext.gregs[REG_ESP] = invalid_stack_pointer;
+#elif defined(__x86_64)
+  context.context.uc_mcontext.gregs[REG_RSP] = invalid_stack_pointer;
+#elif defined(__ARM_EABI__)
+  context.context.uc_mcontext.arm_sp = invalid_stack_pointer;
+#elif defined(__aarch64__)
+  context.context.uc_mcontext.sp = invalid_stack_pointer;
+#elif defined(__mips__)
+  context.context.uc_mcontext.gregs[MD_CONTEXT_MIPS_REG_SP] =
+      invalid_stack_pointer;
+#else
+# error "This code has not been ported to your platform yet."
+#endif
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + kMDWriterUnitTestFileName;
+  // NOTE: In previous versions of Breakpad, WriteMinidump() would fail if
+  // presented with an invalid stack pointer.
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), child, &context, sizeof(context)));
+
+  // Read the minidump. Ensure that the memory region is present
+  Minidump minidump(templ);
+  ASSERT_TRUE(minidump.Read());
+
+  // TODO(ted.mielczarek,mkrebs): Enable this part of the test once
+  // https://breakpad.appspot.com/413002/ is committed.
+#if 0
+  // Make sure there's a thread without a stack.  NOTE: It's okay if
+  // GetThreadList() shows the error: "ERROR: MinidumpThread has a memory
+  // region problem".
+  MinidumpThreadList* dump_thread_list = minidump.GetThreadList();
+  ASSERT_TRUE(dump_thread_list);
+  bool found_empty_stack = false;
+  for (int i = 0; i < dump_thread_list->thread_count(); i++) {
+    MinidumpThread* thread = dump_thread_list->GetThreadAtIndex(i);
+    ASSERT_TRUE(thread->thread() != NULL);
+    // When the stack size is zero bytes, GetMemory() returns NULL.
+    if (thread->GetMemory() == NULL) {
+      found_empty_stack = true;
+      break;
+    }
+  }
+  // NOTE: If you fail this, first make sure that "invalid_stack_pointer"
+  // above is indeed set to an invalid address.
+  ASSERT_TRUE(found_empty_stack);
+#endif
+
+  close(fds[1]);
+  IGNORE_EINTR(waitpid(child, nullptr, 0));
+}
+
+// Test that limiting the size of the minidump works.
+TEST(MinidumpWriterTest, MinidumpSizeLimit) {
+  static const int kNumberOfThreadsInHelperProgram = 40;
+
+  char number_of_threads_arg[3];
+  sprintf(number_of_threads_arg, "%d", kNumberOfThreadsInHelperProgram);
+
+  string helper_path(GetHelperBinary());
+  if (helper_path.empty()) {
+    FAIL() << "Couldn't find helper binary";
+    exit(1);
+  }
+
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  pid_t child_pid = fork();
+  if (child_pid == 0) {
+    // In child process.
+    close(fds[0]);
+
+    // Pass the pipe fd and the number of threads as arguments.
+    char pipe_fd_string[8];
+    sprintf(pipe_fd_string, "%d", fds[1]);
+    execl(helper_path.c_str(),
+          helper_path.c_str(),
+          pipe_fd_string,
+          number_of_threads_arg,
+          NULL);
+  }
+  close(fds[1]);
+
+  // Wait for all child threads to indicate that they have started
+  for (int threads = 0; threads < kNumberOfThreadsInHelperProgram; threads++) {
+    struct pollfd pfd;
+    memset(&pfd, 0, sizeof(pfd));
+    pfd.fd = fds[0];
+    pfd.events = POLLIN | POLLERR;
+
+    const int r = HANDLE_EINTR(poll(&pfd, 1, 1000));
+    ASSERT_EQ(1, r);
+    ASSERT_TRUE(pfd.revents & POLLIN);
+    uint8_t junk;
+    ASSERT_EQ(read(fds[0], &junk, sizeof(junk)),
+              static_cast<ssize_t>(sizeof(junk)));
+  }
+  close(fds[0]);
+
+  // There is a race here because we may stop a child thread before
+  // it is actually running the busy loop. Empirically this sleep
+  // is sufficient to avoid the race.
+  usleep(100000);
+
+  // Child and its threads are ready now.
+
+
+  off_t normal_file_size;
+  int total_normal_stack_size = 0;
+  AutoTempDir temp_dir;
+
+  // First, write a minidump with no size limit.
+  {
+    string normal_dump = temp_dir.path() +
+        "/minidump-writer-unittest.dmp";
+    ASSERT_TRUE(WriteMinidump(normal_dump.c_str(), -1,
+                              child_pid, NULL, 0,
+                              MappingList(), AppMemoryList()));
+    struct stat st;
+    ASSERT_EQ(0, stat(normal_dump.c_str(), &st));
+    ASSERT_GT(st.st_size, 0);
+    normal_file_size = st.st_size;
+
+    Minidump minidump(normal_dump);
+    ASSERT_TRUE(minidump.Read());
+    MinidumpThreadList* dump_thread_list = minidump.GetThreadList();
+    ASSERT_TRUE(dump_thread_list);
+    for (unsigned int i = 0; i < dump_thread_list->thread_count(); i++) {
+      MinidumpThread* thread = dump_thread_list->GetThreadAtIndex(i);
+      ASSERT_TRUE(thread->thread() != NULL);
+      // When the stack size is zero bytes, GetMemory() returns NULL.
+      MinidumpMemoryRegion* memory = thread->GetMemory();
+      ASSERT_TRUE(memory != NULL);
+      total_normal_stack_size += memory->GetSize();
+    }
+  }
+
+  // Second, write a minidump with a size limit big enough to not trigger
+  // anything.
+  {
+    // Set size limit arbitrarily 1MB larger than the normal file size -- such
+    // that the limiting code will not kick in.
+    const off_t minidump_size_limit = normal_file_size + 1024*1024;
+
+    string same_dump = temp_dir.path() +
+        "/minidump-writer-unittest-same.dmp";
+    ASSERT_TRUE(WriteMinidump(same_dump.c_str(), minidump_size_limit,
+                              child_pid, NULL, 0,
+                              MappingList(), AppMemoryList()));
+    struct stat st;
+    ASSERT_EQ(0, stat(same_dump.c_str(), &st));
+    // Make sure limiting wasn't actually triggered.  NOTE: If you fail this,
+    // first make sure that "minidump_size_limit" above is indeed set to a
+    // large enough value -- the limit-checking code in minidump_writer.cc
+    // does just a rough estimate.
+    ASSERT_EQ(normal_file_size, st.st_size);
+  }
+
+  // Third, write a minidump with a size limit small enough to be triggered.
+  {
+    // Set size limit to some arbitrary amount, such that the limiting code
+    // will kick in.  The equation used to set this value was determined by
+    // simply reversing the size-limit logic a little bit in order to pick a
+    // size we know will trigger it.  The definition of
+    // kLimitAverageThreadStackLength here was copied from class
+    // MinidumpWriter in minidump_writer.cc.
+    static const unsigned kLimitAverageThreadStackLength = 8 * 1024;
+    off_t minidump_size_limit = kNumberOfThreadsInHelperProgram *
+        kLimitAverageThreadStackLength;
+    // If, in reality, each of the threads' stack is *smaller* than
+    // kLimitAverageThreadStackLength, the normal file size could very well be
+    // smaller than the arbitrary limit that was just set.  In that case,
+    // either of these numbers should trigger the size-limiting code, but we
+    // might as well pick the smallest.
+    if (normal_file_size < minidump_size_limit)
+      minidump_size_limit = normal_file_size;
+
+    string limit_dump = temp_dir.path() +
+        "/minidump-writer-unittest-limit.dmp";
+    ASSERT_TRUE(WriteMinidump(limit_dump.c_str(), minidump_size_limit,
+                              child_pid, NULL, 0,
+                              MappingList(), AppMemoryList()));
+    struct stat st;
+    ASSERT_EQ(0, stat(limit_dump.c_str(), &st));
+    ASSERT_GT(st.st_size, 0);
+    // Make sure the file size is at least smaller than the original.  If this
+    // fails because it's the same size, then the size-limit logic didn't kick
+    // in like it was supposed to.
+    EXPECT_LT(st.st_size, normal_file_size);
+
+    Minidump minidump(limit_dump);
+    ASSERT_TRUE(minidump.Read());
+    MinidumpThreadList* dump_thread_list = minidump.GetThreadList();
+    ASSERT_TRUE(dump_thread_list);
+    int total_limit_stack_size = 0;
+    for (unsigned int i = 0; i < dump_thread_list->thread_count(); i++) {
+      MinidumpThread* thread = dump_thread_list->GetThreadAtIndex(i);
+      ASSERT_TRUE(thread->thread() != NULL);
+      // When the stack size is zero bytes, GetMemory() returns NULL.
+      MinidumpMemoryRegion* memory = thread->GetMemory();
+      ASSERT_TRUE(memory != NULL);
+      total_limit_stack_size += memory->GetSize();
+    }
+
+    // Make sure stack size shrunk by at least 1KB per extra thread.  The
+    // definition of kLimitBaseThreadCount here was copied from class
+    // MinidumpWriter in minidump_writer.cc.
+    // Note: The 1KB is arbitrary, and assumes that the thread stacks are big
+    // enough to shrink by that much.  For example, if each thread stack was
+    // originally only 2KB, the current size-limit logic wouldn't actually
+    // shrink them because that's the size to which it tries to shrink.  If
+    // you fail this part of the test due to something like that, the test
+    // logic should probably be improved to account for your situation.
+    const unsigned kLimitBaseThreadCount = 20;
+    const unsigned kMinPerExtraThreadStackReduction = 1024;
+    const int min_expected_reduction = (kNumberOfThreadsInHelperProgram -
+        kLimitBaseThreadCount) * kMinPerExtraThreadStackReduction;
+    EXPECT_LT(total_limit_stack_size,
+              total_normal_stack_size - min_expected_reduction);
+  }
+
+  // Kill the helper program.
+  kill(child_pid, SIGKILL);
+  IGNORE_EINTR(waitpid(child_pid, nullptr, 0));
+}
+
+}  // namespace
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest_utils.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest_utils.cc
new file mode 100644
index 0000000000..3e27be73cc
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest_utils.cc
@@ -0,0 +1,66 @@
+// Copyright (c) 2011 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// minidump_writer_unittest_utils.cc:
+// Shared routines used by unittests under linux/minidump_writer.
+
+#include <limits.h>
+#include <stdlib.h>
+
+#include "linux/minidump_writer/minidump_writer_unittest_utils.h"
+#include "common/linux/safe_readlink.h"
+#include "common/using_std_string.h"
+
+namespace google_breakpad {
+
+string GetHelperBinary() {
+  string helper_path;
+  char *bindir = getenv("bindir");
+  if (bindir) {
+    helper_path = string(bindir) + "/";
+  } else {
+    // Locate helper binary next to the current binary.
+    char self_path[PATH_MAX];
+    if (!SafeReadLink("/proc/self/exe", self_path)) {
+      return "";
+    }
+    helper_path = string(self_path);
+    size_t pos = helper_path.rfind('/');
+    if (pos == string::npos) {
+      return "";
+    }
+    helper_path.erase(pos + 1);
+  }
+
+  helper_path += "linux_dumper_unittest_helper";
+
+  return helper_path;
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest_utils.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest_utils.h
new file mode 100644
index 0000000000..bc7b7c83f4
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/minidump_writer_unittest_utils.h
@@ -0,0 +1,49 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// minidump_writer_unittest_utils.h:
+// Shared routines used by unittests under linux/minidump_writer.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_UNITTEST_UTILS_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_UNITTEST_UTILS_H_
+
+#include <string>
+
+#include "common/using_std_string.h"
+
+namespace google_breakpad {
+
+// Returns the full path to linux_dumper_unittest_helper.  The full path is
+// discovered either by using the environment variable "bindir" or by using
+// the location of the main module of the currently running process.
+string GetHelperBinary();
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_UNITTEST_UTILS_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/proc_cpuinfo_reader.h b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/proc_cpuinfo_reader.h
new file mode 100644
index 0000000000..94a637fc15
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/proc_cpuinfo_reader.h
@@ -0,0 +1,130 @@
+// Copyright (c) 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_
+
+#include <stdint.h>
+#include <assert.h>
+#include <string.h>
+
+#include "linux/minidump_writer/line_reader.h"
+#include "common/linux/linux_libc_support.h"
+#include "third_party/lss/linux_syscall_support.h"
+
+namespace google_breakpad {
+
+// A class for reading /proc/cpuinfo without using fopen/fgets or other
+// functions which may allocate memory.
+class ProcCpuInfoReader {
+public:
+  ProcCpuInfoReader(int fd)
+    : line_reader_(fd), pop_count_(-1) {
+  }
+
+  // Return the next field name, or NULL in case of EOF.
+  // field: (output) Pointer to zero-terminated field name.
+  // Returns true on success, or false on EOF or error (line too long).
+  bool GetNextField(const char** field) {
+    for (;;) {
+      const char* line;
+      unsigned line_len;
+
+      // Try to read next line.
+      if (pop_count_ >= 0) {
+        line_reader_.PopLine(pop_count_);
+        pop_count_ = -1;
+      }
+
+      if (!line_reader_.GetNextLine(&line, &line_len))
+        return false;
+
+      pop_count_ = static_cast<int>(line_len);
+
+      const char* line_end = line + line_len;
+
+      // Expected format: <field-name> <space>+ ':' <space> <value>
+      // Note that:
+      //   - empty lines happen.
+      //   - <field-name> can contain spaces.
+      //   - some fields have an empty <value>
+      char* sep = static_cast<char*>(my_memchr(line, ':', line_len));
+      if (sep == NULL)
+        continue;
+
+      // Record the value. Skip leading space after the column to get
+      // its start.
+      const char* val = sep+1;
+      while (val < line_end && my_isspace(*val))
+        val++;
+
+      value_ = val;
+      value_len_ = static_cast<size_t>(line_end - val);
+
+      // Remove trailing spaces before the column to properly 0-terminate
+      // the field name.
+      while (sep > line && my_isspace(sep[-1]))
+        sep--;
+
+      if (sep == line)
+        continue;
+
+      // zero-terminate field name.
+      *sep = '\0';
+
+      *field = line;
+      return true;
+    }
+  }
+
+  // Return the field value. This must be called after a succesful
+  // call to GetNextField().
+  const char* GetValue() {
+    assert(value_);
+    return value_;
+  }
+
+  // Same as GetValue(), but also returns the length in characters of
+  // the value.
+  const char* GetValueAndLen(size_t* length) {
+    assert(value_);
+    *length = value_len_;
+    return value_;
+  }
+
+private:
+  LineReader line_reader_;
+  int pop_count_;
+  const char* value_;
+  size_t value_len_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_PROC_CPUINFO_READER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/minidump_writer/proc_cpuinfo_reader_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/proc_cpuinfo_reader_unittest.cc
new file mode 100644
index 0000000000..26fe9e3a38
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/minidump_writer/proc_cpuinfo_reader_unittest.cc
@@ -0,0 +1,199 @@
+// Copyright (c) 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#include "linux/minidump_writer/proc_cpuinfo_reader.h"
+#include "breakpad_googletest_includes.h"
+#include "common/linux/tests/auto_testfile.h"
+
+using namespace google_breakpad;
+
+#if !defined(__ANDROID__)
+#define TEMPDIR "/tmp"
+#else
+#define TEMPDIR "/data/local/tmp"
+#endif
+
+
+namespace {
+
+typedef testing::Test ProcCpuInfoReaderTest;
+
+class ScopedTestFile : public AutoTestFile {
+public:
+  explicit ScopedTestFile(const char* text)
+    : AutoTestFile("proc_cpuinfo_reader", text) {
+  }
+};
+
+}
+
+TEST(ProcCpuInfoReaderTest, EmptyFile) {
+  ScopedTestFile file("");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char *field;
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, OneLineTerminated) {
+  ScopedTestFile file("foo : bar\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char *field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, OneLine) {
+  ScopedTestFile file("foo : bar");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char *field;
+  size_t value_len;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValueAndLen(&value_len));
+  ASSERT_EQ(3U, value_len);
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, TwoLinesTerminated) {
+  ScopedTestFile file("foo : bar\nzoo : tut\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValue());
+
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("zoo", field);
+  ASSERT_STREQ("tut", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, SkipMalformedLine) {
+  ScopedTestFile file("this line should have a column\nfoo : bar\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, SkipOneEmptyLine) {
+  ScopedTestFile file("\n\nfoo : bar\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, SkipEmptyField) {
+  ScopedTestFile file(" : bar\nzoo : tut\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("zoo", field);
+  ASSERT_STREQ("tut", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, SkipTwoEmptyLines) {
+  ScopedTestFile file("foo : bar\n\n\nfoo : bar\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValue());
+
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  ASSERT_STREQ("bar", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, FieldWithSpaces) {
+  ScopedTestFile file("foo bar    : zoo\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo bar", field);
+  ASSERT_STREQ("zoo", reader.GetValue());
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}
+
+TEST(ProcCpuInfoReaderTest, EmptyValue) {
+  ScopedTestFile file("foo :\n");
+  ASSERT_TRUE(file.IsOk());
+  ProcCpuInfoReader reader(file.GetFd());
+
+  const char* field;
+  ASSERT_TRUE(reader.GetNextField(&field));
+  ASSERT_STREQ("foo", field);
+  size_t value_len;
+  ASSERT_STREQ("", reader.GetValueAndLen(&value_len));
+  ASSERT_EQ(0U, value_len);
+
+  ASSERT_FALSE(reader.GetNextField(&field));
+}