Revert of Turn components/crash into a layered component.

components/crash/browser/crash_handler_host_linux.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/crash/browser/crash_handler_host_linux.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
+#include "base/format_macros.h"
+#include "base/linux_util.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/path_service.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/rand_util.h"
+#include "base/single_thread_task_runner.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/threading/thread.h"
+#include "breakpad/src/client/linux/handler/exception_handler.h"
+#include "breakpad/src/client/linux/minidump_writer/linux_dumper.h"
+#include "breakpad/src/client/linux/minidump_writer/minidump_writer.h"
+#include "components/crash/app/breakpad_linux_impl.h"
+#include "content/public/browser/browser_thread.h"
+
+#if defined(OS_ANDROID) && !defined(__LP64__)
+#include <sys/linux-syscalls.h>
+
+#define SYS_read __NR_read
+#endif
+
+using content::BrowserThread;
+using google_breakpad::ExceptionHandler;
+
+namespace breakpad {
+
+namespace {
+
+const size_t kNumFDs = 1;
+// The length of the control message:
+const size_t kControlMsgSize =
+    CMSG_SPACE(kNumFDs * sizeof(int)) + CMSG_SPACE(sizeof(struct ucred));
+// The length of the regular payload:
+const size_t kCrashContextSize = sizeof(ExceptionHandler::CrashContext);
+
+// Handles the crash dump and frees the allocated BreakpadInfo struct.
+void CrashDumpTask(CrashHandlerHostLinux* handler,
+                   scoped_ptr<BreakpadInfo> info) {
+  if (handler->IsShuttingDown() && info->upload) {
+    base::DeleteFile(base::FilePath(info->filename), false);
+#if defined(ADDRESS_SANITIZER)
+    base::DeleteFile(base::FilePath(info->log_filename), false);
+#endif
+    return;
+  }
+
+  HandleCrashDump(*info);
+  delete[] info->filename;
+#if defined(ADDRESS_SANITIZER)
+  delete[] info->log_filename;
+  delete[] info->asan_report_str;
+#endif
+  delete[] info->process_type;
+  delete[] info->distro;
+  delete info->crash_keys;
+}
+
+}  // namespace
+
+// Since instances of CrashHandlerHostLinux are leaked, they are only destroyed
+// at the end of the processes lifetime, which is greater in span than the
+// lifetime of the IO message loop. Thus, all calls to base::Bind() use
+// non-refcounted pointers.
+
+CrashHandlerHostLinux::CrashHandlerHostLinux(const std::string& process_type,
+                                             const base::FilePath& dumps_path,
+                                             bool upload)
+    : process_type_(process_type),
+      dumps_path_(dumps_path),
+      upload_(upload),
+      shutting_down_(false),
+      worker_pool_token_(BrowserThread::GetBlockingPool()->GetSequenceToken()) {
+  int fds[2];
+  // We use SOCK_SEQPACKET rather than SOCK_DGRAM to prevent the process from
+  // sending datagrams to other sockets on the system. The sandbox may prevent
+  // the process from calling socket() to create new sockets, but it'll still
+  // inherit some sockets. With PF_UNIX+SOCK_DGRAM, it can call sendmsg to send
+  // a datagram to any (abstract) socket on the same system. With
+  // SOCK_SEQPACKET, this is prevented.
+  CHECK_EQ(0, socketpair(AF_UNIX, SOCK_SEQPACKET, 0, fds));
+  static const int on = 1;
+
+  // Enable passcred on the server end of the socket
+  CHECK_EQ(0, setsockopt(fds[1], SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)));
+
+  process_socket_ = fds[0];
+  browser_socket_ = fds[1];
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&CrashHandlerHostLinux::Init, base::Unretained(this)));
+}
+
+CrashHandlerHostLinux::~CrashHandlerHostLinux() {
+  close(process_socket_);
+  close(browser_socket_);
+}
+
+void CrashHandlerHostLinux::StartUploaderThread() {
+  uploader_thread_.reset(
+      new base::Thread(process_type_ + "_crash_uploader"));
+  uploader_thread_->Start();
+}
+
+void CrashHandlerHostLinux::Init() {
+  base::MessageLoopForIO* ml = base::MessageLoopForIO::current();
+  CHECK(ml->WatchFileDescriptor(
+      browser_socket_, true /* persistent */,
+      base::MessageLoopForIO::WATCH_READ,
+      &file_descriptor_watcher_, this));
+  ml->AddDestructionObserver(this);
+}
+
+void CrashHandlerHostLinux::OnFileCanWriteWithoutBlocking(int fd) {
+  NOTREACHED();
+}
+
+void CrashHandlerHostLinux::OnFileCanReadWithoutBlocking(int fd) {
+  DCHECK_EQ(browser_socket_, fd);
+
+  // A process has crashed and has signaled us by writing a datagram
+  // to the death signal socket. The datagram contains the crash context needed
+  // for writing the minidump as well as a file descriptor and a credentials
+  // block so that they can't lie about their pid.
+  //
+  // The message sender is in components/crash/app/breakpad_linux.cc.
+
+  struct msghdr msg = {0};
+  struct iovec iov[kCrashIovSize];
+
+  scoped_ptr<char[]> crash_context(new char[kCrashContextSize]);
+#if defined(ADDRESS_SANITIZER)
+  scoped_ptr<char[]> asan_report(new char[kMaxAsanReportSize + 1]);
+#endif
+
+  scoped_ptr<CrashKeyStorage> crash_keys(new CrashKeyStorage);
+  google_breakpad::SerializedNonAllocatingMap* serialized_crash_keys;
+  size_t crash_keys_size = crash_keys->Serialize(
+      const_cast<const google_breakpad::SerializedNonAllocatingMap**>(
+          &serialized_crash_keys));
+
+  char* tid_buf_addr = NULL;
+  int tid_fd = -1;
+  uint64_t uptime;
+  size_t oom_size;
+  char control[kControlMsgSize];
+  const ssize_t expected_msg_size =
+      kCrashContextSize +
+      sizeof(tid_buf_addr) + sizeof(tid_fd) +
+      sizeof(uptime) +
+#if defined(ADDRESS_SANITIZER)
+      kMaxAsanReportSize + 1 +
+#endif
+      sizeof(oom_size) +
+      crash_keys_size;
+  iov[0].iov_base = crash_context.get();
+  iov[0].iov_len = kCrashContextSize;
+  iov[1].iov_base = &tid_buf_addr;
+  iov[1].iov_len = sizeof(tid_buf_addr);
+  iov[2].iov_base = &tid_fd;
+  iov[2].iov_len = sizeof(tid_fd);
+  iov[3].iov_base = &uptime;
+  iov[3].iov_len = sizeof(uptime);
+  iov[4].iov_base = &oom_size;
+  iov[4].iov_len = sizeof(oom_size);
+  iov[5].iov_base = serialized_crash_keys;
+  iov[5].iov_len = crash_keys_size;
+#if !defined(ADDRESS_SANITIZER)
+  static_assert(5 == kCrashIovSize - 1, "kCrashIovSize should equal 6");
+#else
+  iov[6].iov_base = asan_report.get();
+  iov[6].iov_len = kMaxAsanReportSize + 1;
+  static_assert(6 == kCrashIovSize - 1, "kCrashIovSize should equal 7");
+#endif
+  msg.msg_iov = iov;
+  msg.msg_iovlen = kCrashIovSize;
+  msg.msg_control = control;
+  msg.msg_controllen = kControlMsgSize;
+
+  const ssize_t msg_size = HANDLE_EINTR(recvmsg(browser_socket_, &msg, 0));
+  if (msg_size < 0) {
+    LOG(ERROR) << "Error reading from death signal socket. Crash dumping"
+               << " is disabled."
+               << " msg_size:" << msg_size
+               << " errno:" << errno;
+    file_descriptor_watcher_.StopWatchingFileDescriptor();
+    return;
+  }
+  const bool bad_message = (msg_size != expected_msg_size ||
+                            msg.msg_controllen != kControlMsgSize ||
+                            msg.msg_flags & ~MSG_TRUNC);
+  base::ScopedFD signal_fd;
+  pid_t crashing_pid = -1;
+  if (msg.msg_controllen > 0) {
+    // Walk the control payload and extract the file descriptor and
+    // validated pid.
+    for (struct cmsghdr *hdr = CMSG_FIRSTHDR(&msg); hdr;
+         hdr = CMSG_NXTHDR(&msg, hdr)) {
+      if (hdr->cmsg_level != SOL_SOCKET)
+        continue;
+      if (hdr->cmsg_type == SCM_RIGHTS) {
+        const size_t len = hdr->cmsg_len -
+            (((uint8_t*)CMSG_DATA(hdr)) - (uint8_t*)hdr);
+        DCHECK_EQ(0U, len % sizeof(int));
+        const size_t num_fds = len / sizeof(int);
+        if (num_fds != kNumFDs) {
+          // A nasty process could try and send us too many descriptors and
+          // force a leak.
+          LOG(ERROR) << "Death signal contained wrong number of descriptors;"
+                     << " num_fds:" << num_fds;
+          for (size_t i = 0; i < num_fds; ++i)
+            close(reinterpret_cast<int*>(CMSG_DATA(hdr))[i]);
+          return;
+        }
+        DCHECK(!signal_fd.is_valid());
+        int fd = reinterpret_cast<int*>(CMSG_DATA(hdr))[0];
+        DCHECK_GE(fd, 0);  // The kernel should never send a negative fd.
+        signal_fd.reset(fd);
+      } else if (hdr->cmsg_type == SCM_CREDENTIALS) {
+        DCHECK_EQ(-1, crashing_pid);
+        const struct ucred *cred =
+            reinterpret_cast<struct ucred*>(CMSG_DATA(hdr));
+        crashing_pid = cred->pid;
+      }
+    }
+  }
+
+  if (bad_message) {
+    LOG(ERROR) << "Received death signal message with the wrong size;"
+               << " msg.msg_controllen:" << msg.msg_controllen
+               << " msg.msg_flags:" << msg.msg_flags
+               << " kCrashContextSize:" << kCrashContextSize
+               << " kControlMsgSize:" << kControlMsgSize;
+    return;
+  }
+  if (crashing_pid == -1 || !signal_fd.is_valid()) {
+    LOG(ERROR) << "Death signal message didn't contain all expected control"
+               << " messages";
+    return;
+  }
+
+  // The crashing TID set inside the compromised context via
+  // sys_gettid() in ExceptionHandler::HandleSignal might be wrong (if
+  // the kernel supports PID namespacing) and may need to be
+  // translated.
+  //
+  // We expect the crashing thread to be in sys_read(), waiting for us to
+  // write to |signal_fd|. Most newer kernels where we have the different pid
+  // namespaces also have /proc/[pid]/syscall, so we can look through
+  // |actual_crashing_pid|'s thread group and find the thread that's in the
+  // read syscall with the right arguments.
+
+  std::string expected_syscall_data;
+  // /proc/[pid]/syscall is formatted as follows:
+  // syscall_number arg1 ... arg6 sp pc
+  // but we just check syscall_number through arg3.
+  base::StringAppendF(&expected_syscall_data, "%d 0x%x %p 0x1 ",
+                      SYS_read, tid_fd, tid_buf_addr);
+  bool syscall_supported = false;
+  pid_t crashing_tid =
+      base::FindThreadIDWithSyscall(crashing_pid,
+                                    expected_syscall_data,
+                                    &syscall_supported);
+  if (crashing_tid == -1) {
+    // We didn't find the thread we want. Maybe it didn't reach
+    // sys_read() yet or the thread went away.  We'll just take a
+    // guess here and assume the crashing thread is the thread group
+    // leader.  If procfs syscall is not supported by the kernel, then
+    // we assume the kernel also does not support TID namespacing and
+    // trust the TID passed by the crashing process.
+    LOG(WARNING) << "Could not translate tid - assuming crashing thread is "
+        "thread group leader; syscall_supported=" << syscall_supported;
+    crashing_tid = crashing_pid;
+  }
+
+  ExceptionHandler::CrashContext* bad_context =
+      reinterpret_cast<ExceptionHandler::CrashContext*>(crash_context.get());
+  bad_context->tid = crashing_tid;
+
+  scoped_ptr<BreakpadInfo> info(new BreakpadInfo);
+
+  info->fd = -1;
+  info->process_type_length = process_type_.length();
+  // Freed in CrashDumpTask().
+  char* process_type_str = new char[info->process_type_length + 1];
+  process_type_.copy(process_type_str, info->process_type_length);
+  process_type_str[info->process_type_length] = '\0';
+  info->process_type = process_type_str;
+
+  // Memory released from scoped_ptrs below are also freed in CrashDumpTask().
+  info->crash_keys = crash_keys.release();
+#if defined(ADDRESS_SANITIZER)
+  asan_report[kMaxAsanReportSize] = '\0';
+  info->asan_report_str = asan_report.release();
+  info->asan_report_length = strlen(info->asan_report_str);
+#endif
+
+  info->process_start_time = uptime;
+  info->oom_size = oom_size;
+#if defined(OS_ANDROID)
+  // Nothing gets uploaded in android.
+  info->upload = false;
+#else
+  info->upload = upload_;
+#endif
+
+
+  BrowserThread::GetBlockingPool()->PostSequencedWorkerTask(
+      worker_pool_token_,
+      FROM_HERE,
+      base::Bind(&CrashHandlerHostLinux::WriteDumpFile,
+                 base::Unretained(this),
+                 base::Passed(&info),
+                 base::Passed(&crash_context),
+                 crashing_pid,
+                 signal_fd.release()));
+}
+
+void CrashHandlerHostLinux::WriteDumpFile(scoped_ptr<BreakpadInfo> info,
+                                          scoped_ptr<char[]> crash_context,
+                                          pid_t crashing_pid,
+                                          int signal_fd) {
+  DCHECK(BrowserThread::GetBlockingPool()->IsRunningSequenceOnCurrentThread(
+      worker_pool_token_));
+
+  // Set |info->distro| here because base::GetLinuxDistro() needs to run on a
+  // blocking thread.
+  std::string distro = base::GetLinuxDistro();
+  info->distro_length = distro.length();
+  // Freed in CrashDumpTask().
+  char* distro_str = new char[info->distro_length + 1];
+  distro.copy(distro_str, info->distro_length);
+  distro_str[info->distro_length] = '\0';
+  info->distro = distro_str;
+
+  base::FilePath dumps_path("/tmp");
+  PathService::Get(base::DIR_TEMP, &dumps_path);
+  if (!info->upload)
+    dumps_path = dumps_path_;
+  const std::string minidump_filename =
+      base::StringPrintf("%s/chromium-%s-minidump-%016" PRIx64 ".dmp",
+                         dumps_path.value().c_str(),
+                         process_type_.c_str(),
+                         base::RandUint64());
+
+  if (!google_breakpad::WriteMinidump(minidump_filename.c_str(),
+                                      kMaxMinidumpFileSize,
+                                      crashing_pid,
+                                      crash_context.get(),
+                                      kCrashContextSize,
+                                      google_breakpad::MappingList(),
+                                      google_breakpad::AppMemoryList())) {
+    LOG(ERROR) << "Failed to write crash dump for pid " << crashing_pid;
+  }
+#if defined(ADDRESS_SANITIZER)
+  // Create a temporary file holding the AddressSanitizer report.
+  const base::FilePath log_path =
+      base::FilePath(minidump_filename).ReplaceExtension("log");
+  base::WriteFile(log_path, info->asan_report_str, info->asan_report_length);
+#endif
+
+  // Freed in CrashDumpTask().
+  char* minidump_filename_str = new char[minidump_filename.length() + 1];
+  minidump_filename.copy(minidump_filename_str, minidump_filename.length());
+  minidump_filename_str[minidump_filename.length()] = '\0';
+  info->filename = minidump_filename_str;
+#if defined(ADDRESS_SANITIZER)
+  // Freed in CrashDumpTask().
+  char* minidump_log_filename_str = new char[minidump_filename.length() + 1];
+  minidump_filename.copy(minidump_log_filename_str, minidump_filename.length());
+  memcpy(minidump_log_filename_str + minidump_filename.length() - 3, "log", 3);
+  minidump_log_filename_str[minidump_filename.length()] = '\0';
+  info->log_filename = minidump_log_filename_str;
+#endif
+  info->pid = crashing_pid;
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&CrashHandlerHostLinux::QueueCrashDumpTask,
+                 base::Unretained(this),
+                 base::Passed(&info),
+                 signal_fd));
+}
+
+void CrashHandlerHostLinux::QueueCrashDumpTask(scoped_ptr<BreakpadInfo> info,
+                                               int signal_fd) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // Send the done signal to the process: it can exit now.
+  struct msghdr msg = {0};
+  struct iovec done_iov;
+  done_iov.iov_base = const_cast<char*>("\x42");
+  done_iov.iov_len = 1;
+  msg.msg_iov = &done_iov;
+  msg.msg_iovlen = 1;
+
+  HANDLE_EINTR(sendmsg(signal_fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL));
+  close(signal_fd);
+
+  uploader_thread_->task_runner()->PostTask(
+      FROM_HERE,
+      base::Bind(&CrashDumpTask, base::Unretained(this), base::Passed(&info)));
+}
+
+void CrashHandlerHostLinux::WillDestroyCurrentMessageLoop() {
+  file_descriptor_watcher_.StopWatchingFileDescriptor();
+
+  // If we are quitting and there are crash dumps in the queue, turn them into
+  // no-ops.
+  shutting_down_ = true;
+  uploader_thread_->Stop();
+}
+
+bool CrashHandlerHostLinux::IsShuttingDown() const {
+  return shutting_down_;
+}
+
+}  // namespace breakpad