Merge of Breakpad Chrome Linux fork

A=agl, Lei Zhang
R=nealsid, agl



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@384 4c0a9323-5329-0410-9bdc-e9ce6186880e

10 files changed, 2179 insertions, 0 deletions

diff --git a/src/client/linux/minidump_writer/directory_reader.h b/src/client/linux/minidump_writer/directory_reader.h
new file mode 100644
index 00000000..4698b7e5
--- /dev/null
+++ b/src/client/linux/minidump_writer/directory_reader.h
@@ -0,0 +1,105 @@
+// 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_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;
+    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/src/client/linux/minidump_writer/directory_reader_unittest.cc b/src/client/linux/minidump_writer/directory_reader_unittest.cc
new file mode 100644
index 00000000..3034e619
--- /dev/null
+++ b/src/client/linux/minidump_writer/directory_reader_unittest.cc
@@ -0,0 +1,77 @@
+// 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 "client/linux/minidump_writer/directory_reader.h"
+#include "breakpad_googletest_includes.h"
+
+using namespace google_breakpad;
+
+namespace {
+typedef testing::Test DirectoryReaderTest;
+}
+
+TEST(DirectoryReaderTest, CompareResults) {
+  std::set<std::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/src/client/linux/minidump_writer/line_reader.h b/src/client/linux/minidump_writer/line_reader.h
new file mode 100644
index 00000000..5c0a1154
--- /dev/null
+++ b/src/client/linux/minidump_writer/line_reader.h
@@ -0,0 +1,130 @@
+// 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_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 = 512;
+
+  // 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;
+    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/src/client/linux/minidump_writer/line_reader_unittest.cc b/src/client/linux/minidump_writer/line_reader_unittest.cc
new file mode 100644
index 00000000..222a098e
--- /dev/null
+++ b/src/client/linux/minidump_writer/line_reader_unittest.cc
@@ -0,0 +1,184 @@
+// 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 "client/linux/minidump_writer/line_reader.h"
+#include "breakpad_googletest_includes.h"
+
+using namespace google_breakpad;
+
+static int TemporaryFile() {
+  static const char templ[] = "/tmp/line-reader-unittest-XXXXXX";
+  char templ_copy[sizeof(templ)];
+  memcpy(templ_copy, templ, sizeof(templ));
+  const int fd = mkstemp(templ_copy);
+  if (fd >= 0)
+    unlink(templ_copy);
+
+  return fd;
+}
+
+namespace {
+typedef testing::Test LineReaderTest;
+}
+
+TEST(LineReaderTest, EmptyFile) {
+  const int fd = TemporaryFile();
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+
+  close(fd);
+}
+
+TEST(LineReaderTest, OneLineTerminated) {
+  const int fd = TemporaryFile();
+  write(fd, "a\n", 2);
+  lseek(fd, 0, SEEK_SET);
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, 1);
+  ASSERT_EQ(line[0], 'a');
+  ASSERT_EQ(line[1], 0);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+
+  close(fd);
+}
+
+TEST(LineReaderTest, OneLine) {
+  const int fd = TemporaryFile();
+  write(fd, "a", 1);
+  lseek(fd, 0, SEEK_SET);
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, 1);
+  ASSERT_EQ(line[0], 'a');
+  ASSERT_EQ(line[1], 0);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+
+  close(fd);
+}
+
+TEST(LineReaderTest, TwoLinesTerminated) {
+  const int fd = TemporaryFile();
+  write(fd, "a\nb\n", 4);
+  lseek(fd, 0, SEEK_SET);
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, 1);
+  ASSERT_EQ(line[0], 'a');
+  ASSERT_EQ(line[1], 0);
+  reader.PopLine(len);
+
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, 1);
+  ASSERT_EQ(line[0], 'b');
+  ASSERT_EQ(line[1], 0);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+
+  close(fd);
+}
+
+TEST(LineReaderTest, TwoLines) {
+  const int fd = TemporaryFile();
+  write(fd, "a\nb", 3);
+  lseek(fd, 0, SEEK_SET);
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, 1);
+  ASSERT_EQ(line[0], 'a');
+  ASSERT_EQ(line[1], 0);
+  reader.PopLine(len);
+
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, 1);
+  ASSERT_EQ(line[0], 'b');
+  ASSERT_EQ(line[1], 0);
+  reader.PopLine(len);
+
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+
+  close(fd);
+}
+
+TEST(LineReaderTest, MaxLength) {
+  const int fd = TemporaryFile();
+  char l[LineReader::kMaxLineLen - 1];
+  memset(l, 'a', sizeof(l));
+  write(fd, l, sizeof(l));
+  lseek(fd, 0, SEEK_SET);
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_TRUE(reader.GetNextLine(&line, &len));
+  ASSERT_EQ(len, sizeof(l));
+  ASSERT_TRUE(memcmp(l, line, sizeof(l)) == 0);
+  ASSERT_EQ(line[len], 0);
+
+  close(fd);
+}
+
+TEST(LineReaderTest, TooLong) {
+  const int fd = TemporaryFile();
+  char l[LineReader::kMaxLineLen];
+  memset(l, 'a', sizeof(l));
+  write(fd, l, sizeof(l));
+  lseek(fd, 0, SEEK_SET);
+  LineReader reader(fd);
+
+  const char *line;
+  unsigned len;
+  ASSERT_FALSE(reader.GetNextLine(&line, &len));
+
+  close(fd);
+}
diff --git a/src/client/linux/minidump_writer/linux_dumper.cc b/src/client/linux/minidump_writer/linux_dumper.cc
new file mode 100644
index 00000000..e821db7d
--- /dev/null
+++ b/src/client/linux/minidump_writer/linux_dumper.cc
@@ -0,0 +1,419 @@
+// 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.
+
+// 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 "client/linux/minidump_writer/linux_dumper.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+
+#include "client/linux/minidump_writer/directory_reader.h"
+#include "client/linux/minidump_writer/line_reader.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/linux/linux_syscall_support.h"
+
+// Suspend 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;
+    }
+  }
+  return true;
+}
+
+// Resume a thread by detaching from it.
+static bool ResumeThread(pid_t pid) {
+  return sys_ptrace(PTRACE_DETACH, pid, NULL, NULL) >= 0;
+}
+
+namespace google_breakpad {
+
+LinuxDumper::LinuxDumper(int pid)
+    : pid_(pid),
+      threads_suspened_(false),
+      threads_(&allocator_, 8),
+      mappings_(&allocator_) {
+}
+
+bool LinuxDumper::Init() {
+  return EnumerateThreads(&threads_) &&
+         EnumerateMappings(&mappings_);
+}
+
+bool LinuxDumper::ThreadsSuspend() {
+  if (threads_suspened_)
+    return true;
+  bool good = true;
+  for (size_t i = 0; i < threads_.size(); ++i)
+    good &= SuspendThread(threads_[i]);
+  threads_suspened_ = true;
+  return good;
+}
+
+bool LinuxDumper::ThreadsResume() {
+  if (!threads_suspened_)
+    return false;
+  bool good = true;
+  for (size_t i = 0; i < threads_.size(); ++i)
+    good &= ResumeThread(threads_[i]);
+  threads_suspened_ = false;
+  return good;
+}
+
+void
+LinuxDumper::BuildProcPath(char* path, pid_t pid, const char* node) const {
+  assert(path);
+  if (!path) {
+    return;
+  }
+
+  path[0] = '\0';
+
+  const unsigned pid_len = my_int_len(pid);
+
+  assert(node);
+  if (!node) {
+    return;
+  }
+
+  size_t node_len = my_strlen(node);
+  assert(node_len < NAME_MAX);
+  if (node_len >= NAME_MAX) {
+    return;
+  }
+
+  assert(node_len > 0);
+  if (node_len == 0) {
+    return;
+  }
+
+  assert(pid > 0);
+  if (pid <= 0) {
+    return;
+  }
+
+  const size_t total_length = 6 + pid_len + 1 + node_len;
+
+  assert(total_length < NAME_MAX);
+  if (total_length >= NAME_MAX) {
+    return;
+  }
+
+  memcpy(path, "/proc/", 6);
+  my_itos(path + 6, pid, pid_len);
+  memcpy(path + 6 + pid_len, "/", 1);
+  memcpy(path + 6 + pid_len + 1, node, node_len);
+  memcpy(path + total_length, "\0", 1);
+}
+
+void*
+LinuxDumper::FindBeginningOfLinuxGateSharedLibrary(const pid_t pid) const {
+  char auxv_path[80];
+  BuildProcPath(auxv_path, pid, "auxv");
+
+  // If BuildProcPath errors out due to invalid input, we'll handle it when
+  // we try to sys_open the file.
+
+  // Find the AT_SYSINFO_EHDR entry for linux-gate.so
+  // See http://www.trilithium.com/johan/2005/08/linux-gate/ for more
+  // information.
+  int fd = sys_open(auxv_path, O_RDONLY, 0);
+  if (fd < 0) {
+    return NULL;
+  }
+
+  elf_aux_entry one_aux_entry;
+  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_SYSINFO_EHDR) {
+      close(fd);
+      return reinterpret_cast<void*>(one_aux_entry.a_un.a_val);
+    }
+  }
+  close(fd);
+  return NULL;
+}
+
+bool
+LinuxDumper::EnumerateMappings(wasteful_vector<MappingInfo*>* result) const {
+  char maps_path[80];
+  BuildProcPath(maps_path, pid_, "maps");
+
+  // 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, so we use the aux vector to find it's
+  // load location and special case it's entry when creating the list
+  // of mappings.
+  const void* linux_gate_loc;
+  linux_gate_loc = FindBeginningOfLinuxGateSharedLibrary(pid_);
+
+  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 == ' ') {
+        const char* i3 = my_read_hex_ptr(&offset, i2 + 6 /* skip ' rwxp ' */);
+        if (*i3 == ' ') {
+          MappingInfo* const module = new(allocator_) MappingInfo;
+          memset(module, 0, sizeof(MappingInfo));
+          module->start_addr = start_addr;
+          module->size = end_addr - start_addr;
+          module->offset = offset;
+          const char* name = NULL;
+          // Only copy name if the name is a valid path name, or if
+          // we've found the VDSO image
+          if ((name = my_strchr(line, '/')) != NULL) {
+            const unsigned l = my_strlen(name);
+            if (l < sizeof(module->name))
+              memcpy(module->name, name, l);
+          } else if (linux_gate_loc &&
+                     reinterpret_cast<void*>(module->start_addr) ==
+                     linux_gate_loc) {
+            memcpy(module->name,
+                   kLinuxGateLibraryName,
+                   my_strlen(kLinuxGateLibraryName));
+            module->offset = 0;
+          }
+          result->push_back(module);
+        }
+      }
+    }
+    line_reader->PopLine(line_len);
+  }
+
+  sys_close(fd);
+
+  return result->size() > 0;
+}
+
+// Parse /proc/$pid/task to list all the threads of the process identified by
+// pid.
+bool LinuxDumper::EnumerateThreads(wasteful_vector<pid_t>* result) const {
+  char task_path[80];
+  BuildProcPath(task_path, pid_, "task");
+
+  const int fd = sys_open(task_path, O_RDONLY | O_DIRECTORY, 0);
+  if (fd < 0)
+    return false;
+  DirectoryReader* dir_reader = new(allocator_) DirectoryReader(fd);
+
+  // The directory may contain duplicate entries which we filter by assuming
+  // that they are consecutive.
+  int last_tid = -1;
+  const char* dent_name;
+  while (dir_reader->GetNextEntry(&dent_name)) {
+    if (my_strcmp(dent_name, ".") &&
+        my_strcmp(dent_name, "..")) {
+      int tid = 0;
+      if (my_strtoui(&tid, dent_name) &&
+          last_tid != tid) {
+        last_tid = tid;
+        result->push_back(tid);
+      }
+    }
+    dir_reader->PopEntry();
+  }
+
+  sys_close(fd);
+  return true;
+}
+
+// Read thread info from /proc/$pid/status.
+// Fill out the |tgid|, |ppid| and |pid| members of |info|. If unavailible,
+// these members are set to -1. Returns true iff all three members are
+// availible.
+bool LinuxDumper::ThreadInfoGet(pid_t tid, ThreadInfo* info) {
+  assert(info != NULL);
+  char status_path[80];
+  BuildProcPath(status_path, tid, "status");
+
+  const int fd = open(status_path, O_RDONLY);
+  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);
+  }
+
+  if (info->ppid == -1 || info->tgid == -1)
+    return false;
+
+  if (sys_ptrace(PTRACE_GETREGS, tid, NULL, &info->regs) == -1 ||
+      sys_ptrace(PTRACE_GETFPREGS, tid, NULL, &info->fpregs) == -1) {
+    return false;
+  }
+
+#if defined(__i386) || defined(__x86_64)
+  if (sys_ptrace(PTRACE_GETFPXREGS, tid, NULL, &info->fpxregs) == -1)
+    return false;
+
+  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
+
+  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));
+#else
+#error "This code hasn't been ported to your platform yet."
+#endif
+
+  if (!GetStackInfo(&info->stack, &info->stack_len,
+                    (uintptr_t) stack_pointer))
+    return false;
+
+  return true;
+}
+
+// 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) {
+#if defined(__i386) || defined(__x86_64)
+  static const bool stack_grows_down = true;
+  static const uintptr_t page_size = 4096;
+#else
+#error "This code has not been ported to your platform yet."
+#endif
+  // Move the stack pointer to the bottom of the page that it's in.
+  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 unsigned kStackToCapture = 32 * 1024;
+
+  const MappingInfo* mapping = FindMapping(stack_pointer);
+  if (!mapping)
+    return false;
+  if (stack_grows_down) {
+    const ptrdiff_t offset = stack_pointer - (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;
+  } else {
+    const ptrdiff_t offset = stack_pointer - (uint8_t*) mapping->start_addr;
+    *stack_len = offset > kStackToCapture ? kStackToCapture : offset;
+    *stack = stack_pointer - *stack_len;
+  }
+
+  return true;
+}
+
+// static
+void LinuxDumper::CopyFromProcess(void* dest, pid_t child, const void* src,
+                                  size_t length) {
+  unsigned long tmp;
+  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;
+    memcpy(local + done, &tmp, l);
+    done += l;
+  }
+}
+
+// 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;
+}
+
+}  // namespace google_breakpad
diff --git a/src/client/linux/minidump_writer/linux_dumper.h b/src/client/linux/minidump_writer/linux_dumper.h
new file mode 100644
index 00000000..252e9ee6
--- /dev/null
+++ b/src/client/linux/minidump_writer/linux_dumper.h
@@ -0,0 +1,142 @@
+// 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_LINUX_DUMPER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_DUMPER_H_
+
+#include <elf.h>
+#include <stdint.h>
+#include <sys/user.h>
+#include <linux/limits.h>
+
+#include "common/linux/memory.h"
+
+namespace google_breakpad {
+
+typedef typeof(((struct user*) 0)->u_debugreg[0]) debugreg_t;
+
+// Typedef for our parsing of the auxv variables in /proc/pid/auxv.
+#if defined(__i386)
+typedef Elf32_auxv_t elf_aux_entry;
+#elif defined(__x86_64__)
+typedef Elf64_auxv_t elf_aux_entry;
+#endif
+// 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";
+
+// We produce one of these structures for each thread in the crashed process.
+struct ThreadInfo {
+  pid_t tgid;   // thread group id
+  pid_t ppid;   // parent process
+
+  // Even on platforms where the stack grows down, the following will point to
+  // the smallest address in the stack.
+  const void* stack;  // pointer to the stack area
+  size_t stack_len;  // length of the stack to copy
+
+  user_regs_struct regs;
+  user_fpregs_struct fpregs;
+#if defined(__i386) || defined(__x86_64)
+  user_fpxregs_struct fpxregs;
+
+  static const unsigned kNumDebugRegisters = 8;
+  debugreg_t dregs[8];
+#endif
+};
+
+// One of these is produced for each mapping in the process (i.e. line in
+// /proc/$x/maps).
+struct MappingInfo {
+  uintptr_t start_addr;
+  size_t size;
+  size_t offset;  // offset into the backed file.
+  char name[NAME_MAX];
+};
+
+class LinuxDumper {
+ public:
+  explicit LinuxDumper(pid_t pid);
+
+  // Parse the data for |threads| and |mappings|.
+  bool Init();
+
+  // Suspend/resume all threads in the given process.
+  bool ThreadsSuspend();
+  bool ThreadsResume();
+
+  // Read information about the given thread. Returns true on success. One must
+  // have called |ThreadsSuspend| first.
+  bool ThreadInfoGet(pid_t tid, ThreadInfo* info);
+
+  // 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 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);
+
+  PageAllocator* allocator() { return &allocator_; }
+
+  // memcpy from a remote process.
+  static void CopyFromProcess(void* dest, pid_t child, const void* src,
+                              size_t length);
+
+  // Builds a proc path for a certain pid for a node.  path is a
+  // character array that is overwritten, and node is the final node
+  // without any slashes.
+  void BuildProcPath(char* path, pid_t pid, const char* node) const;
+
+  // Utility method to find the location of where the kernel has
+  // mapped linux-gate.so in memory(shows up in /proc/pid/maps as
+  // [vdso], but we can't guarantee that it's the only virtual dynamic
+  // shared object.  Parsing the auxilary vector for AT_SYSINFO_EHDR
+  // is the safest way to go.)
+  void* FindBeginningOfLinuxGateSharedLibrary(const pid_t pid) const;
+ private:
+  bool EnumerateMappings(wasteful_vector<MappingInfo*>* result) const;
+  bool EnumerateThreads(wasteful_vector<pid_t>* result) const;
+
+  const pid_t pid_;
+
+  mutable PageAllocator allocator_;
+
+  bool threads_suspened_;
+  wasteful_vector<pid_t> threads_;  // the ids of all the threads
+  wasteful_vector<MappingInfo*> mappings_;  // info from /proc/<pid>/maps
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_LINUX_DUMPER_H_
diff --git a/src/client/linux/minidump_writer/linux_dumper_unittest.cc b/src/client/linux/minidump_writer/linux_dumper_unittest.cc
new file mode 100644
index 00000000..f5ed914b
--- /dev/null
+++ b/src/client/linux/minidump_writer/linux_dumper_unittest.cc
@@ -0,0 +1,118 @@
+// 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 <unistd.h>
+
+#include "client/linux/minidump_writer/linux_dumper.h"
+#include "breakpad_googletest_includes.h"
+
+using namespace google_breakpad;
+
+namespace {
+typedef testing::Test LinuxDumperTest;
+}
+
+TEST(LinuxDumperTest, Setup) {
+  LinuxDumper dumper(getpid());
+}
+
+TEST(LinuxDumperTest, FindMappings) {
+  LinuxDumper dumper(getpid());
+  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(LinuxDumperTest, ThreadList) {
+  LinuxDumper dumper(getpid());
+  ASSERT_TRUE(dumper.Init());
+
+  ASSERT_GE(dumper.threads().size(), 1);
+  bool found = false;
+  for (size_t i = 0; i < dumper.threads().size(); ++i) {
+    if (dumper.threads()[i] == getpid()) {
+      found = true;
+      break;
+    }
+  }
+}
+
+TEST(LinuxDumperTest, BuildProcPath) {
+  const pid_t pid = getpid();
+  LinuxDumper dumper(pid);
+
+  char maps_path[256] = "dummymappath";
+  char maps_path_expected[256];
+  snprintf(maps_path_expected, sizeof(maps_path_expected),
+           "/proc/%d/maps", pid);
+  dumper.BuildProcPath(maps_path, pid, "maps");
+  ASSERT_STREQ(maps_path, maps_path_expected);
+
+  // In release mode, we expect BuildProcPath to handle the invalid
+  // parameters correctly and fill map_path with an empty
+  // NULL-terminated string.
+#ifdef NDEBUG
+  snprintf(maps_path, sizeof(maps_path), "dummymappath");
+  dumper.BuildProcPath(maps_path, 0, "maps");
+  EXPECT_STREQ(maps_path, "");
+
+  snprintf(maps_path, sizeof(maps_path), "dummymappath");
+  dumper.BuildProcPath(maps_path, getpid(), "");
+  EXPECT_STREQ(maps_path, "");
+
+  snprintf(maps_path, sizeof(maps_path), "dummymappath");
+  dumper.BuildProcPath(maps_path, getpid(), NULL);
+  EXPECT_STREQ(maps_path, "");
+#endif
+}
+
+TEST(LinuxDumperTest, MappingsIncludeLinuxGate) {
+  LinuxDumper dumper(getpid());
+  ASSERT_TRUE(dumper.Init());
+
+  void* linux_gate_loc = dumper.FindBeginningOfLinuxGateSharedLibrary(getpid());
+  if (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));
+  }
+}
diff --git a/src/client/linux/minidump_writer/minidump_writer.cc b/src/client/linux/minidump_writer/minidump_writer.cc
new file mode 100644
index 00000000..a99309f3
--- /dev/null
+++ b/src/client/linux/minidump_writer/minidump_writer.cc
@@ -0,0 +1,872 @@
+// 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.
+
+// 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 "client/linux/minidump_writer/minidump_writer.h"
+#include "client/minidump_file_writer-inl.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/ucontext.h>
+#include <sys/user.h>
+#include <sys/utsname.h>
+
+#include "client/minidump_file_writer.h"
+#include "google_breakpad/common/minidump_format.h"
+#include "google_breakpad/common/minidump_cpu_amd64.h"
+#include "google_breakpad/common/minidump_cpu_x86.h"
+
+#include "client/linux/handler/exception_handler.h"
+#include "client/linux/minidump_writer/line_reader.h"
+#include "client/linux/minidump_writer//linux_dumper.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/linux/linux_syscall_support.h"
+
+// These are additional minidump stream values which are specific to the linux
+// breakpad implementation.
+enum {
+  MD_LINUX_CPU_INFO              = 0x47670003,    /* /proc/cpuinfo    */
+  MD_LINUX_PROC_STATUS           = 0x47670004,    /* /proc/$x/status  */
+  MD_LINUX_LSB_RELEASE           = 0x47670005,    /* /etc/lsb-release */
+  MD_LINUX_CMD_LINE              = 0x47670006,    /* /proc/$x/cmdline */
+  MD_LINUX_ENVIRON               = 0x47670007,    /* /proc/$x/environ */
+  MD_LINUX_AUXV                  = 0x47670008,    /* /proc/$x/auxv    */
+};
+
+// Minidump defines register structures which are different from the raw
+// structures which we get from the kernel. These are platform specific
+// functions to juggle the ucontext and user structures into minidump format.
+#if defined(__i386)
+typedef MDRawContextX86 RawContextCPU;
+
+// Write a uint16_t to memory
+//   out: memory location to write to
+//   v: value to write.
+static void U16(void* out, uint16_t v) {
+  memcpy(out, &v, sizeof(v));
+}
+
+// Write a uint32_t to memory
+//   out: memory location to write to
+//   v: value to write.
+static void U32(void* out, uint32_t v) {
+  memcpy(out, &v, sizeof(v));
+}
+
+// Juggle an x86 user_(fp|fpx|)regs_struct into minidump format
+//   out: the minidump structure
+//   info: the collection of register structures.
+static void CPUFillFromThreadInfo(MDRawContextX86 *out,
+                                  const google_breakpad::ThreadInfo &info) {
+  out->context_flags = MD_CONTEXT_X86_ALL;
+
+  out->dr0 = info.dregs[0];
+  out->dr1 = info.dregs[1];
+  out->dr2 = info.dregs[2];
+  out->dr3 = info.dregs[3];
+  // 4 and 5 deliberatly omitted because they aren't included in the minidump
+  // format.
+  out->dr6 = info.dregs[6];
+  out->dr7 = info.dregs[7];
+
+  out->gs = info.regs.xgs;
+  out->fs = info.regs.xfs;
+  out->es = info.regs.xes;
+  out->ds = info.regs.xds;
+
+  out->edi = info.regs.edi;
+  out->esi = info.regs.esi;
+  out->ebx = info.regs.ebx;
+  out->edx = info.regs.edx;
+  out->ecx = info.regs.ecx;
+  out->eax = info.regs.eax;
+
+  out->ebp = info.regs.ebp;
+  out->eip = info.regs.eip;
+  out->cs = info.regs.xcs;
+  out->eflags = info.regs.eflags;
+  out->esp = info.regs.esp;
+  out->ss = info.regs.xss;
+
+  out->float_save.control_word = info.fpregs.cwd;
+  out->float_save.status_word = info.fpregs.swd;
+  out->float_save.tag_word = info.fpregs.twd;
+  out->float_save.error_offset = info.fpregs.fip;
+  out->float_save.error_selector = info.fpregs.fcs;
+  out->float_save.data_offset = info.fpregs.foo;
+  out->float_save.data_selector = info.fpregs.fos;
+
+  // 8 registers * 10 bytes per register.
+  memcpy(out->float_save.register_area, info.fpregs.st_space, 10 * 8);
+
+  // This matches the Intel fpsave format.
+  U16(out->extended_registers + 0, info.fpregs.cwd);
+  U16(out->extended_registers + 2, info.fpregs.swd);
+  U16(out->extended_registers + 4, info.fpregs.twd);
+  U16(out->extended_registers + 6, info.fpxregs.fop);
+  U32(out->extended_registers + 8, info.fpxregs.fip);
+  U16(out->extended_registers + 12, info.fpxregs.fcs);
+  U32(out->extended_registers + 16, info.fpregs.foo);
+  U16(out->extended_registers + 20, info.fpregs.fos);
+  U32(out->extended_registers + 24, info.fpxregs.mxcsr);
+
+  memcpy(out->extended_registers + 32, &info.fpxregs.st_space, 128);
+  memcpy(out->extended_registers + 160, &info.fpxregs.xmm_space, 128);
+}
+
+// Juggle an x86 ucontext into minidump format
+//   out: the minidump structure
+//   info: the collection of register structures.
+static void CPUFillFromUContext(MDRawContextX86 *out, const ucontext *uc,
+                                const struct _libc_fpstate* fp) {
+  const greg_t* regs = uc->uc_mcontext.gregs;
+
+  out->context_flags = MD_CONTEXT_X86_FULL |
+                       MD_CONTEXT_X86_FLOATING_POINT;
+
+  out->gs = regs[REG_GS];
+  out->fs = regs[REG_FS];
+  out->es = regs[REG_ES];
+  out->ds = regs[REG_DS];
+
+  out->edi = regs[REG_EDI];
+  out->esi = regs[REG_ESI];
+  out->ebx = regs[REG_EBX];
+  out->edx = regs[REG_EDX];
+  out->ecx = regs[REG_ECX];
+  out->eax = regs[REG_EAX];
+
+  out->ebp = regs[REG_EBP];
+  out->eip = regs[REG_EIP];
+  out->cs = regs[REG_CS];
+  out->eflags = regs[REG_EFL];
+  out->esp = regs[REG_UESP];
+  out->ss = regs[REG_SS];
+
+  out->float_save.control_word = fp->cw;
+  out->float_save.status_word = fp->sw;
+  out->float_save.tag_word = fp->tag;
+  out->float_save.error_offset = fp->ipoff;
+  out->float_save.error_selector = fp->cssel;
+  out->float_save.data_offset = fp->dataoff;
+  out->float_save.data_selector = fp->datasel;
+
+  // 8 registers * 10 bytes per register.
+  memcpy(out->float_save.register_area, fp->_st, 10 * 8);
+}
+
+#elif defined(__x86_64)
+typedef MDRawContextAMD64 RawContextCPU;
+
+static void CPUFillFromThreadInfo(MDRawContextAMD64 *out,
+                                  const google_breakpad::ThreadInfo &info) {
+  out->context_flags = MD_CONTEXT_AMD64_FULL |
+                       MD_CONTEXT_AMD64_SEGMENTS;
+
+  out->cs = info.regs.cs;
+
+  out->ds = info.regs.ds;
+  out->es = info.regs.es;
+  out->fs = info.regs.fs;
+  out->gs = info.regs.gs;
+
+  out->ss = info.regs.ss;
+  out->eflags = info.regs.eflags;
+
+  out->dr0 = info.dregs[0];
+  out->dr1 = info.dregs[1];
+  out->dr2 = info.dregs[2];
+  out->dr3 = info.dregs[3];
+  // 4 and 5 deliberatly omitted because they aren't included in the minidump
+  // format.
+  out->dr6 = info.dregs[6];
+  out->dr7 = info.dregs[7];
+
+  out->rax = info.regs.rax;
+  out->rcx = info.regs.rcx;
+  out->rdx = info.regs.rdx;
+  out->rbx = info.regs.rbx;
+
+  out->rsp = info.regs.rsp;
+
+  out->rbp = info.regs.rbp;
+  out->rsi = info.regs.rsi;
+  out->rdi = info.regs.rdi;
+  out->r8 = info.regs.r8;
+  out->r9 = info.regs.r9;
+  out->r10 = info.regs.r10;
+  out->r11 = info.regs.r11;
+  out->r12 = info.regs.r12;
+  out->r13 = info.regs.r13;
+  out->r14 = info.regs.r14;
+  out->r15 = info.regs.r15;
+
+  out->rip = info.regs.rip;
+
+  out->flt_save.control_word = info.fpregs.cwd;
+  out->flt_save.status_word = info.fpregs.swd;
+  out->flt_save.tag_word = info.fpregs.twd;
+  out->flt_save.error_opcode = info.fpregs.fop;
+  out->flt_save.error_offset = info.fpregs.rip;
+  out->flt_save.error_selector = 0; // We don't have this.
+  out->flt_save.data_offset = info.fpregs.rdp;
+  out->flt_save.data_selector = 0;  // We don't have this.
+  out->flt_save.mx_csr = info.fpregs.mxcsr;
+  out->flt_save.mx_csr_mask = info.fpregs.mxcsr_mask;
+  memcpy(&out->flt_save.float_registers, &info.fpregs.st_space, 8 * 16);
+  memcpy(&out->flt_save.xmm_registers, &info.fpregs.xmm_space, 16 * 16);
+}
+
+static void CPUFillFromUContext(MDRawContextAMD64 *out, const ucontext *uc,
+                                const struct _libc_fpstate* fpregs) {
+  const greg_t* regs = uc->gregs;
+
+  out->context_flags = MD_CONTEXT_AMD64_FULL;
+
+  out->cs = regs[REG_CSGSFS] & 0xffff;
+
+  out->fs = (regs[REG_CSGSFS] >> 32) & 0xffff;
+  out->gs = (regs[REG_CSGSFS] >> 16) & 0xffff;
+
+  out->eflags = regs[REG_EFL];
+
+  out->rax = regs[REG_RAX];
+  out->rcx = regs[REG_RCX];
+  out->rdx = regs[REG_RDX];
+  out->rbx = regs[REG_RBX];
+
+  out->rsp = regs[REG_RSP];
+  out->rbp = regs[REG_RBP];
+  out->rsi = regs[REG_RSI];
+  out->rdi = regs[REG_RDI];
+  out->r8 = regs[REG_R8];
+  out->r9 = regs[REG_R9];
+  out->r10 = regs[REG_R10];
+  out->r11 = regs[REG_R11];
+  out->r12 = regs[REG_R12];
+  out->r13 = regs[REG_R13];
+  out->r14 = regs[REG_R14];
+  out->r15 = regs[REG_R15];
+
+  out->rip = regs[REG_RIP];
+
+  out->flt_save.control_word = fpregs->cwd;
+  out->flt_save.status_word = fpregs->swd;
+  out->flt_save.tag_word = fpregs->ftw;
+  out->flt_save.error_opcode = fpregs->fop;
+  out->flt_save.error_offset = fpregs->rip;
+  out->flt_save.data_offset = fpregs->rdp;
+  out->flt_save.error_selector = 0; // We don't have this.
+  out->flt_save.data_selector = 0;  // We don't have this.
+  out->flt_save.mx_csr = fpregs->mxcsr;
+  out->flt_save.mx_csr_mask = fpregs->mxcsr_mask;
+  memcpy(&out->flt_save.float_registers, &fpregs->_st, 8 * 16);
+  memcpy(&out->flt_save.xmm_registers, &fpregs->_xmm, 16 * 16);
+}
+
+#else
+#error "This code has not been ported to your platform yet."
+#endif
+
+namespace google_breakpad {
+
+class MinidumpWriter {
+ public:
+  MinidumpWriter(const char* filename,
+                 pid_t crashing_pid,
+                 const ExceptionHandler::CrashContext* context)
+      : filename_(filename),
+        siginfo_(&context->siginfo),
+        ucontext_(&context->context),
+        float_state_(&context->float_state),
+        crashing_tid_(context->tid),
+        dumper_(crashing_pid) {
+  }
+
+  bool Init() {
+    return dumper_.Init() && minidump_writer_.Open(filename_) &&
+           dumper_.ThreadsSuspend();
+  }
+
+  ~MinidumpWriter() {
+    minidump_writer_.Close();
+    dumper_.ThreadsResume();
+  }
+
+  bool Dump() {
+    // A minidump file contains a number of tagged streams. This is the number
+    // of stream which we write.
+    static const unsigned kNumWriters = 11;
+
+    TypedMDRVA<MDRawHeader> header(&minidump_writer_);
+    TypedMDRVA<MDRawDirectory> dir(&minidump_writer_);
+    if (!header.Allocate())
+      return false;
+    if (!dir.AllocateArray(kNumWriters))
+      return false;
+    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 (!WriteMappings(&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, crashing_tid_, "status"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_LSB_RELEASE;
+    if (!WriteFile(&dirent.location, "/etc/lsb-release"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_CMD_LINE;
+    if (!WriteProcFile(&dirent.location, crashing_tid_, "cmdline"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_ENVIRON;
+    if (!WriteProcFile(&dirent.location, crashing_tid_, "environ"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_AUXV;
+    if (!WriteProcFile(&dirent.location, crashing_tid_, "auxv"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    dirent.stream_type = MD_LINUX_AUXV;
+    if (!WriteProcFile(&dirent.location, crashing_tid_, "maps"))
+      NullifyDirectoryEntry(&dirent);
+    dir.CopyIndex(dir_index++, &dirent);
+
+    // If you add more directory entries, don't forget to update kNumWriters,
+    // above.
+
+    dumper_.ThreadsResume();
+    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;
+
+    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 (thread.thread_id == crashing_tid_) {
+        const void* stack;
+        size_t stack_len;
+        if (!dumper_.GetStackInfo(&stack, &stack_len, GetStackPointer()))
+          return false;
+        UntypedMDRVA memory(&minidump_writer_);
+        if (!memory.Allocate(stack_len))
+          return false;
+        uint8_t* stack_copy = (uint8_t*) dumper_.allocator()->Alloc(stack_len);
+        dumper_.CopyFromProcess(stack_copy, thread.thread_id, stack, stack_len);
+        memory.Copy(stack_copy, stack_len);
+        thread.stack.start_of_memory_range = (uintptr_t) (stack);
+        thread.stack.memory = memory.location();
+        TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
+        if (!cpu.Allocate())
+          return false;
+        my_memset(cpu.get(), 0, sizeof(RawContextCPU));
+        CPUFillFromUContext(cpu.get(), ucontext_, float_state_);
+        thread.thread_context = cpu.location();
+        crashing_thread_context_ = cpu.location();
+      } else {
+        ThreadInfo info;
+        if (!dumper_.ThreadInfoGet(dumper_.threads()[i], &info))
+          return false;
+        UntypedMDRVA memory(&minidump_writer_);
+        if (!memory.Allocate(info.stack_len))
+          return false;
+        uint8_t* stack_copy =
+            (uint8_t*) dumper_.allocator()->Alloc(info.stack_len);
+        dumper_.CopyFromProcess(stack_copy, thread.thread_id, info.stack,
+                                info.stack_len);
+        memory.Copy(stack_copy, info.stack_len);
+        thread.stack.start_of_memory_range = (uintptr_t)(info.stack);
+        thread.stack.memory = memory.location();
+        TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
+        if (!cpu.Allocate())
+          return false;
+        my_memset(cpu.get(), 0, sizeof(RawContextCPU));
+        CPUFillFromThreadInfo(cpu.get(), info);
+        thread.thread_context = cpu.location();
+      }
+
+      list.CopyIndexAfterObject(i, &thread, sizeof(thread));
+    }
+
+    return true;
+  }
+
+  static bool ShouldIncludeMapping(const MappingInfo& mapping) {
+    if (mapping.name[0] == 0 || // we only want modules with filenames.
+        mapping.offset || // we only want to include one mapping per shared lib.
+        mapping.size < 4096) {  // too small to get a signature for.
+      return false;
+    }
+
+    return true;
+  }
+
+  // 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 = 0;
+
+    for (unsigned i = 0; i < dumper_.mappings().size(); ++i) {
+      const MappingInfo& mapping = *dumper_.mappings()[i];
+      if (ShouldIncludeMapping(mapping))
+        num_output_mappings++;
+    }
+
+    TypedMDRVA<uint32_t> list(&minidump_writer_);
+    if (!list.AllocateObjectAndArray(num_output_mappings, sizeof(MDRawModule)))
+      return false;
+
+    dirent->stream_type = MD_MODULE_LIST_STREAM;
+    dirent->location = list.location();
+    *list.get() = num_output_mappings;
+
+    for (unsigned i = 0, j = 0; i < num_mappings; ++i) {
+      const MappingInfo& mapping = *dumper_.mappings()[i];
+      if (!ShouldIncludeMapping(mapping))
+        continue;
+
+      MDRawModule mod;
+      my_memset(&mod, 0, sizeof(mod));
+      mod.base_of_image = mapping.start_addr;
+      mod.size_of_image = mapping.size;
+      const size_t filepath_len = my_strlen(mapping.name);
+
+      // Figure out file name from path
+      const char* filename_ptr = mapping.name + filepath_len - 1;
+      while (filename_ptr >= mapping.name) {
+        if (*filename_ptr == '/')
+          break;
+        filename_ptr--;
+      }
+      filename_ptr++;
+      const size_t filename_len = mapping.name + filepath_len - filename_ptr;
+
+      uint8_t cv_buf[MDCVInfoPDB70_minsize + NAME_MAX];
+      uint8_t* cv_ptr = cv_buf;
+      UntypedMDRVA cv(&minidump_writer_);
+      if (!cv.Allocate(MDCVInfoPDB70_minsize + filename_len + 1))
+        return false;
+
+      const uint32_t cv_signature = MD_CVINFOPDB70_SIGNATURE;
+      memcpy(cv_ptr, &cv_signature, sizeof(cv_signature));
+      cv_ptr += sizeof(cv_signature);
+
+      {
+        // We XOR the first page of the file to get a signature for it.
+        uint8_t xor_buf[sizeof(MDGUID)];
+        size_t done = 0;
+        uint8_t* signature = cv_ptr;
+        cv_ptr += sizeof(xor_buf);
+
+        my_memset(signature, 0, sizeof(xor_buf));
+        while (done < 4096) {
+          dumper_.CopyFromProcess(xor_buf, crashing_tid_,
+                                  (void *) (mod.base_of_image + done),
+                                  sizeof(xor_buf));
+          for (unsigned i = 0; i < sizeof(xor_buf); ++i)
+            signature[i] ^= xor_buf[i];
+          done += sizeof(xor_buf);
+        }
+        my_memset(cv_ptr, 0, sizeof(uint32_t));  // Set age to 0 on Linux.
+        cv_ptr += sizeof(uint32_t);
+      }
+
+      // Write pdb_file_name
+      memcpy(cv_ptr, filename_ptr, filename_len + 1);
+      cv.Copy(cv_buf, MDCVInfoPDB70_minsize + filename_len + 1);
+
+      mod.cv_record = cv.location();
+
+      MDLocationDescriptor ld;
+      if (!minidump_writer_.WriteString(mapping.name, filepath_len, &ld))
+        return false;
+      mod.module_name_rva = ld.rva;
+
+      list.CopyIndexAfterObject(j++, &mod, sizeof(mod));
+    }
+
+    return true;
+  }
+
+  bool WriteExceptionStream(MDRawDirectory* dirent) {
+    TypedMDRVA<MDRawExceptionStream> exc(&minidump_writer_);
+    if (!exc.Allocate())
+      return false;
+    my_memset(exc.get(), 0, sizeof(MDRawExceptionStream));
+
+    dirent->stream_type = MD_EXCEPTION_STREAM;
+    dirent->location = exc.location();
+
+    exc.get()->thread_id = crashing_tid_;
+    exc.get()->exception_record.exception_code = siginfo_->si_signo;
+    exc.get()->exception_record.exception_address =
+        (uintptr_t) siginfo_->si_addr;
+    exc.get()->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;
+  }
+
+ private:
+#if defined(__i386)
+  uintptr_t GetStackPointer() {
+    return ucontext_->uc_mcontext.gregs[REG_ESP];
+  }
+#elif defined(__x86_64)
+  uintptr_t GetStackPointer() {
+    return ucontext_->uc_mcontext.gregs[REG_RSP];
+  }
+#else
+#error "This code has not been ported to your platform yet."
+#endif
+
+  void NullifyDirectoryEntry(MDRawDirectory* dirent) {
+    dirent->stream_type = 0;
+    dirent->location.data_size = 0;
+    dirent->location.rva = 0;
+  }
+
+  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";
+    static const size_t vendor_id_name_length = sizeof(vendor_id_name) - 1;
+
+    struct CpuInfoEntry {
+      const char* info_name;
+      int value;
+      bool found;
+    } cpu_info_table[] = {
+      { "processor", -1, false },
+      { "model", 0, false },
+      { "stepping",  0, false },
+      { "cpuid level", 0, false },
+    };
+
+    // processor_architecture should always be set, do this first
+    sys_info->processor_architecture =
+#if defined(__i386)
+        MD_CPU_ARCHITECTURE_X86;
+#elif defined(__x86_64)
+        MD_CPU_ARCHITECTURE_AMD64;
+#else
+#error "Unknown CPU arch"
+#endif
+
+    const int fd = sys_open("/proc/cpuinfo", O_RDONLY, 0);
+    if (fd < 0)
+      return false;
+
+    {
+      PageAllocator allocator;
+      LineReader* const line_reader = new(allocator) LineReader(fd);
+      const char* line;
+      unsigned line_len;
+      while (line_reader->GetNextLine(&line, &line_len)) {
+        for (size_t i = 0;
+             i < sizeof(cpu_info_table) / sizeof(cpu_info_table[0]);
+             i++) {
+          CpuInfoEntry* entry = &cpu_info_table[i];
+          if (entry->found)
+            continue;
+          if (!strncmp(line, entry->info_name, strlen(entry->info_name))) {
+            const char* value = strchr(line, ':');
+            if (!value)
+              continue;
+
+            // the above strncmp only matches the prefix, it might be the wrong
+            // line. i.e. we matched "model name" instead of "model".
+            // check and make sure there is only spaces between the prefix and
+            // the colon.
+            const char* space_ptr = line + strlen(entry->info_name);
+            for (; space_ptr < value; space_ptr++) {
+              if (!isspace(*space_ptr)) {
+                break;
+              }
+            }
+            if (space_ptr != value)
+              continue;
+
+            sscanf(++value, " %d", &(entry->value));
+            entry->found = true;
+          }
+        }
+
+        // special case for vendor_id
+        if (!strncmp(line, vendor_id_name, vendor_id_name_length)) {
+          const char* value = strchr(line, ':');
+          if (!value)
+            goto popline;
+
+          // skip ':" and all the spaces that follows
+          do {
+            value++;
+          } while (isspace(*value));
+
+          if (*value) {
+            size_t length = strlen(value);
+            if (length == 0)
+              goto popline;
+            // we don't want the trailing newline
+            if (value[length - 1] == '\n')
+              length--;
+            // ensure we have space for the value
+            if (length < sizeof(vendor_id))
+              strncpy(vendor_id, value, length);
+          }
+        }
+
+popline:
+        line_reader->PopLine(line_len);
+      }
+      sys_close(fd);
+    }
+
+    // make sure we got everything we wanted
+    for (size_t i = 0;
+         i < sizeof(cpu_info_table) / sizeof(cpu_info_table[0]);
+         i++) {
+      if (!cpu_info_table[i].found) {
+        return false;
+      }
+    }
+    // /proc/cpuinfo contains cpu id, change it into number by adding one.
+    cpu_info_table[0].value++;
+
+    sys_info->number_of_processors = cpu_info_table[0].value;
+    sys_info->processor_level      = cpu_info_table[3].value;
+    sys_info->processor_revision   = cpu_info_table[1].value << 8 |
+                                     cpu_info_table[2].value;
+
+    if (vendor_id[0] != '\0') {
+      memcpy(sys_info->cpu.x86_cpu_info.vendor_id, vendor_id,
+             sizeof(sys_info->cpu.x86_cpu_info.vendor_id));
+    }
+    return true;
+  }
+
+  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 kMaxFileSize = 1024;
+    uint8_t* data = (uint8_t*) dumper_.allocator()->Alloc(kMaxFileSize);
+
+    size_t done = 0;
+    while (done < kMaxFileSize) {
+      ssize_t r;
+      do {
+        r = sys_read(fd, data + done, kMaxFileSize - done);
+      } while (r == -1 && errno == EINTR);
+
+      if (r < 1)
+        break;
+      done += r;
+    }
+    sys_close(fd);
+
+    if (!done)
+      return false;
+
+    UntypedMDRVA memory(&minidump_writer_);
+    if (!memory.Allocate(done))
+      return false;
+    memory.Copy(data, done);
+    *result = memory.location();
+    return true;
+  }
+
+  bool WriteOSInformation(MDRawSystemInfo* sys_info) {
+    sys_info->platform_id = MD_OS_LINUX;
+
+    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 = strlen(separator);
+      size_t info_len = strlen(*cur_info);
+      if (info_len == 0)
+        continue;
+
+      if (space_left < info_len + (first_item ? 0 : separator_len))
+        break;
+
+      if (!first_item) {
+        strcat(buf, separator);
+        space_left -= separator_len;
+      }
+
+      first_item = false;
+      strcat(buf, *cur_info);
+      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[80];
+    memcpy(buf, "/proc/", 6);
+    const unsigned pid_len = my_int_len(pid);
+    my_itos(buf + 6, pid, pid_len);
+    buf[6 + pid_len] = '/';
+    memcpy(buf + 6 + pid_len + 1, filename, my_strlen(filename) + 1);
+    return WriteFile(result, buf);
+  }
+
+  const char* const filename_;  // output filename
+  const siginfo_t* const siginfo_;  // from the signal handler (see sigaction)
+  const struct ucontext* const ucontext_;  // also from the signal handler
+  const struct _libc_fpstate* const float_state_;  // ditto
+  const pid_t crashing_tid_;  // the process which actually crashed
+  LinuxDumper dumper_;
+  MinidumpFileWriter minidump_writer_;
+  MDLocationDescriptor crashing_thread_context_;
+};
+
+bool WriteMinidump(const char* filename, pid_t crashing_process,
+                   const void* blob, size_t blob_size) {
+  if (blob_size != sizeof(ExceptionHandler::CrashContext))
+    return false;
+  const ExceptionHandler::CrashContext* context =
+      reinterpret_cast<const ExceptionHandler::CrashContext*>(blob);
+  MinidumpWriter writer(filename, crashing_process, context);
+  if (!writer.Init())
+    return false;
+  return writer.Dump();
+}
+
+}  // namespace google_breakpad
diff --git a/src/client/linux/minidump_writer/minidump_writer.h b/src/client/linux/minidump_writer/minidump_writer.h
new file mode 100644
index 00000000..579f68cd
--- /dev/null
+++ b/src/client/linux/minidump_writer/minidump_writer.h
@@ -0,0 +1,53 @@
+// 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 <unistd.h>
+
+namespace google_breakpad {
+
+// Write a minidump to the filesystem. This function does not malloc nor use
+// libc functions which may. Thus, it can be used in contexts where the state
+// of the heap may be corrupt.
+//   filename: the filename to write to. This is opened O_EXCL and fails if
+//     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* filename, pid_t crashing_process,
+                   const void* blob, size_t blob_size);
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_H_
diff --git a/src/client/linux/minidump_writer/minidump_writer_unittest.cc b/src/client/linux/minidump_writer/minidump_writer_unittest.cc
new file mode 100644
index 00000000..5ff336ce
--- /dev/null
+++ b/src/client/linux/minidump_writer/minidump_writer_unittest.cc
@@ -0,0 +1,79 @@
+// 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 <unistd.h>
+#include <sys/syscall.h>
+
+#include "client/linux/handler/exception_handler.h"
+#include "client/linux/minidump_writer/minidump_writer.h"
+#include "breakpad_googletest_includes.h"
+
+using namespace google_breakpad;
+
+// This provides a wrapper around system calls which may be
+// interrupted by a signal and return EINTR. See man 7 signal.
+#define HANDLE_EINTR(x) ({ \
+  typeof(x) __eintr_result__; \
+  do { \
+    __eintr_result__ = x; \
+  } while (__eintr_result__ == -1 && errno == EINTR); \
+  __eintr_result__;\
+})
+
+namespace {
+typedef testing::Test MinidumpWriterTest;
+}
+
+TEST(MinidumpWriterTest, Setup) {
+  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);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+
+  char templ[] = "/tmp/minidump-writer-unittest-XXXXXX";
+  mktemp(templ);
+  ASSERT_TRUE(WriteMinidump(templ, child, &context, sizeof(context)));
+  struct stat st;
+  ASSERT_EQ(stat(templ, &st), 0);
+  ASSERT_GT(st.st_size, 0u);
+  unlink(templ);
+
+  close(fds[1]);
+}