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// Copyright 2015 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 <memory>
#include "base/files/file_path.h"
#include "base/files/scoped_file.h"
#include "base/macros.h"
#include "base/process/launch.h"
#include "sandbox/sandbox_export.h"
namespace sandbox {
// Helper class to use the setuid sandbox. This class is to be used
// before launching the setuid helper.
// This class is difficult to use. It has been created by refactoring very old
// code scathered through the Chromium code base.
// A typical use for "A" launching a sandboxed process "B" would be:
// 1. A calls SetupLaunchEnvironment()
// 2. A sets up a base::CommandLine and then amends it with
// PrependWrapper() (or manually, by relying on GetSandboxBinaryPath()).
// 3. A uses SetupLaunchOptions() to arrange for a dummy descriptor for the
// setuid sandbox ABI.
// 4. A launches B with base::LaunchProcess, using the amended
// base::CommandLine.
// (The remaining steps are described within setuid_sandbox_client.h.)
class SANDBOX_EXPORT SetuidSandboxHost {
// All instantation should go through this factory method.
static SetuidSandboxHost* Create();
// The setuid sandbox may still be disabled via the environment.
// This is tracked in
bool IsDisabledViaEnvironment();
// Get the sandbox binary path. This method knows about the
// CHROME_DEVEL_SANDBOX environment variable used for user-managed builds. If
// the sandbox binary cannot be found, it will return an empty FilePath.
base::FilePath GetSandboxBinaryPath();
// Modify |cmd_line| to launch via the setuid sandbox. Crash if the setuid
// sandbox binary cannot be found. |cmd_line| must not be NULL.
void PrependWrapper(base::CommandLine* cmd_line);
// Set-up the launch options for launching via the setuid sandbox. Caller is
// responsible for keeping |dummy_fd| alive until LaunchProcess() completes.
// |options| must not be NULL. This function will append to
// options->fds_to_remap so the caller should take care to append rather than
// overwrite if it has additional FDs.
// (Keeping |dummy_fd| alive is an unfortunate historical artifact of the
// chrome-sandbox ABI.)
void SetupLaunchOptions(base::LaunchOptions* options,
base::ScopedFD* dummy_fd);
// Set-up the environment. This should be done prior to launching the setuid
// helper.
void SetupLaunchEnvironment();
explicit SetuidSandboxHost(std::unique_ptr<base::Environment> env);
// Holds the environment. Will never be NULL.
std::unique_ptr<base::Environment> env_;
} // namespace sandbox