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content / common / zygote / zygote_commands_linux.h [blame]

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_COMMON_ZYGOTE_ZYGOTE_COMMANDS_LINUX_H_
#define CONTENT_COMMON_ZYGOTE_ZYGOTE_COMMANDS_LINUX_H_

#include <stddef.h>

#include "base/posix/global_descriptors.h"

namespace content {

// Contents of the initial message sent from the zygote to the browser right
// after it starts.
static const char kZygoteBootMessage[] = "ZYGOTE_BOOT";

// Contents of the initial message sent from the zygote to the browser when it
// is ready to go.
static const char kZygoteHelloMessage[] = "ZYGOTE_OK";

// Message sent by zygote children to the browser so the browser can discover
// the sending child's process ID.
static const char kZygoteChildPingMessage[] = "CHILD_PING";

// Maximum allowable length for messages sent to the zygote.
const size_t kZygoteMaxMessageLength = 64 * 1024;
static_assert(kZygoteMaxMessageLength < 200 * 1024,
              "Raising kZygoteMaxMessageLength past the maximum single "
              "datagram size for a Unix domain socket will cause long "
              "messages to be silently truncated. See "
              "https://crbug.com/1278226. Values as low as 212992 have "
              "been observed in the wild.");

// File descriptors initialized by the Zygote Host
const int kZygoteSocketPairFd = base::GlobalDescriptors::kBaseDescriptor;

// These are the command codes used on the wire between the browser and the
// zygote.
enum {
  // Fork off a new renderer.
  kZygoteCommandFork = 0,

  // Reap a renderer child.
  kZygoteCommandReap = 1,

  // Check what happened to a child process.
  kZygoteCommandGetTerminationStatus = 2,

  // Read a bitmask of kSandboxLinux*
  kZygoteCommandGetSandboxStatus = 3,

  // Not a real zygote command, but a subcommand used during the zygote fork
  // protocol.  Sends the child's PID as seen from the browser process.
  kZygoteCommandForkRealPID = 4,

  // Reinitialize logging. Needed on ChromeOS, which switches to a log file
  // in the user's home directory once they log in.
  kZygoteCommandReinitializeLogging = 5
};

}  // namespace content

#endif  // CONTENT_COMMON_ZYGOTE_ZYGOTE_COMMANDS_LINUX_H_