Linux: refactor zygote support

http://code.google.com/p/chromium/wiki/LinuxZygote

  * Move Chrome specific bits out of base
  * Move away from the idea of reserved file descriptors (which don't really work
  with zygotes)
  * Load resources before forking renderers (means that we don't need
  communication between the zygote process and the renderers)
  * Make sure that gdb works against the browser again
  * Make sure that we have different ASLR between the renderers and the browser.

http://codereview.chromium.org/119335

(This is a reland. First landed in r18109, reverted in r18112.)


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18291 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 90 insertions, 0 deletions

diff --git a/chrome/browser/zygote_host_linux.cc b/chrome/browser/zygote_host_linux.cc
new file mode 100644
index 0000000..f56e6e93
--- /dev/null
+++ b/chrome/browser/zygote_host_linux.cc
@@ -0,0 +1,90 @@
+// Copyright (c) 2009 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 "chrome/browser/zygote_host_linux.h"
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "base/command_line.h"
+#include "base/eintr_wrapper.h"
+#include "base/logging.h"
+#include "base/path_service.h"
+#include "base/pickle.h"
+#include "base/process_util.h"
+#include "base/unix_domain_socket_posix.h"
+
+#include "chrome/common/chrome_switches.h"
+
+ZygoteHost::ZygoteHost() {
+  std::wstring chrome_path;
+  CHECK(PathService::Get(base::FILE_EXE, &chrome_path));
+  CommandLine cmd_line(chrome_path);
+
+  cmd_line.AppendSwitchWithValue(switches::kProcessType,
+                                 switches::kZygoteProcess);
+
+  int fds[2];
+  CHECK(socketpair(PF_UNIX, SOCK_SEQPACKET, 0, fds) == 0);
+  base::file_handle_mapping_vector fds_to_map;
+  fds_to_map.push_back(std::make_pair(fds[1], 3));
+
+  const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
+  if (browser_command_line.HasSwitch(switches::kZygoteCmdPrefix)) {
+    const std::wstring prefix =
+        browser_command_line.GetSwitchValue(switches::kZygoteCmdPrefix);
+    cmd_line.PrependWrapper(prefix);
+  }
+
+  base::ProcessHandle process;
+  base::LaunchApp(cmd_line.argv(), fds_to_map, false, &process);
+  CHECK(process != -1) << "Failed to launch zygote process";
+
+  close(fds[1]);
+  control_fd_ = fds[0];
+}
+
+ZygoteHost::~ZygoteHost() {
+  close(control_fd_);
+}
+
+pid_t ZygoteHost::ForkRenderer(
+    const std::vector<std::string>& argv,
+    const base::GlobalDescriptors::Mapping& mapping) {
+  Pickle pickle;
+
+  pickle.WriteInt(kCmdFork);
+  pickle.WriteInt(argv.size());
+  for (std::vector<std::string>::const_iterator
+       i = argv.begin(); i != argv.end(); ++i)
+    pickle.WriteString(*i);
+
+  pickle.WriteInt(mapping.size());
+
+  std::vector<int> fds;
+  for (base::GlobalDescriptors::Mapping::const_iterator
+       i = mapping.begin(); i != mapping.end(); ++i) {
+    pickle.WriteUInt32(i->first);
+    fds.push_back(i->second);
+  }
+
+  if (!base::SendMsg(control_fd_, pickle.data(), pickle.size(), fds))
+    return -1;
+
+  pid_t pid;
+  if (HANDLE_EINTR(read(control_fd_, &pid, sizeof(pid))) != sizeof(pid))
+    return -1;
+
+  return pid;
+}
+
+void ZygoteHost::EnsureProcessTerminated(pid_t process) {
+  Pickle pickle;
+
+  pickle.WriteInt(kCmdReap);
+  pickle.WriteInt(process);
+
+  HANDLE_EINTR(write(control_fd_, pickle.data(), pickle.size()));
+}