Update from https://crrev.com/302630

sandbox/linux/syscall_broker/broker_process.cc

Index: sandbox/linux/syscall_broker/broker_process.cc
diff --git a/sandbox/linux/syscall_broker/broker_process.cc b/sandbox/linux/syscall_broker/broker_process.cc
new file mode 100644
index 0000000000000000000000000000000000000000..66b7660af071412d3047aa16f32905d6ea722fdd
--- /dev/null
+++ b/sandbox/linux/syscall_broker/broker_process.cc
@@ -0,0 +1,124 @@
+// Copyright (c) 2012 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 "sandbox/linux/syscall_broker/broker_process.h"
+
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/process/process_metrics.h"
+#include "build/build_config.h"
+#include "sandbox/linux/syscall_broker/broker_client.h"
+#include "sandbox/linux/syscall_broker/broker_host.h"
+
+namespace sandbox {
+
+BrokerProcess::BrokerProcess(int denied_errno,
+                             const std::vector<std::string>& allowed_r_files,
+                             const std::vector<std::string>& allowed_w_files,
+                             bool fast_check_in_client,
+                             bool quiet_failures_for_tests)
+    : initialized_(false),
+      is_child_(false),
+      fast_check_in_client_(fast_check_in_client),
+      quiet_failures_for_tests_(quiet_failures_for_tests),
+      broker_pid_(-1),
+      policy_(denied_errno, allowed_r_files, allowed_w_files),
+      ipc_socketpair_(-1) {
+}
+
+BrokerProcess::~BrokerProcess() {
+  if (initialized_ && ipc_socketpair_ != -1) {
+    // Closing the socket should be enough to notify the child to die,
+    // unless it has been duplicated.
+    PCHECK(0 == IGNORE_EINTR(close(ipc_socketpair_)));
+    PCHECK(0 == kill(broker_pid_, SIGKILL));
+    siginfo_t process_info;
+    // Reap the child.
+    int ret = HANDLE_EINTR(waitid(P_PID, broker_pid_, &process_info, WEXITED));
+    PCHECK(0 == ret);
+  }
+}
+
+bool BrokerProcess::Init(
+    const base::Callback<bool(void)>& broker_process_init_callback) {
+  CHECK(!initialized_);
+  int socket_pair[2];
+  // Use SOCK_SEQPACKET, because we need to preserve message boundaries
+  // but we also want to be notified (recvmsg should return and not block)
+  // when the connection has been broken (one of the processes died).
+  if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, socket_pair)) {
+    LOG(ERROR) << "Failed to create socketpair";
+    return false;
+  }
+
+#if !defined(THREAD_SANITIZER)
+  DCHECK_EQ(1, base::GetNumberOfThreads(base::GetCurrentProcessHandle()));
+#endif
+  int child_pid = fork();
+  if (child_pid == -1) {
+    close(socket_pair[0]);
+    close(socket_pair[1]);
+    return false;
+  }
+  if (child_pid) {
+    // We are the parent and we have just forked our broker process.
+    close(socket_pair[0]);
+    // We should only be able to write to the IPC channel. We'll always send
+    // a new file descriptor to receive the reply on.
+    shutdown(socket_pair[1], SHUT_RD);
+    ipc_socketpair_ = socket_pair[1];
+    is_child_ = false;
+    broker_pid_ = child_pid;
+    broker_client_.reset(
+        new syscall_broker::BrokerClient(policy_,
+                                         ipc_socketpair_,
+                                         fast_check_in_client_,
+                                         quiet_failures_for_tests_));
+    initialized_ = true;
+    return true;
+  } else {
+    // We are the broker.
+    close(socket_pair[1]);
+    // We should only be able to read from this IPC channel. We will send our
+    // replies on a new file descriptor attached to the requests.
+    shutdown(socket_pair[0], SHUT_WR);
+    ipc_socketpair_ = socket_pair[0];
+    is_child_ = true;
+    CHECK(broker_process_init_callback.Run());
+    syscall_broker::BrokerHost broker_host(policy_, ipc_socketpair_);
+    initialized_ = true;
+    for (;;) {
+      broker_host.HandleRequest();
+    }
+    _exit(1);
+  }
+  NOTREACHED();
+}
+
+int BrokerProcess::Access(const char* pathname, int mode) const {
+  RAW_CHECK(initialized_);
+  return broker_client_->Access(pathname, mode);
+}
+
+int BrokerProcess::Open(const char* pathname, int flags) const {
+  RAW_CHECK(initialized_);
+  return broker_client_->Open(pathname, flags);
+}
+
+}  // namespace sandbox.