blob: 0ee5636a48cc384d0aefc8419d63c0df7bfe7484 [file] [log] [blame]
// Copyright 2014 The Chromium OS 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 <grp.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <base/files/file_path.h>
#include <base/files/file_util.h>
#include <base/logging.h>
#include <base/memory/scoped_ptr.h>
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>
#include <chromeos/ui/chromium_command_builder.h>
#include <chromeos/ui/util.h>
#include <chromeos/ui/x_server_runner.h>
using chromeos::ui::ChromiumCommandBuilder;
using chromeos::ui::XServerRunner;
using chromeos::ui::util::EnsureDirectoryExists;
using chromeos::ui::util::SetPermissions;
namespace {
// Authority file used for running the X server.
const char kXauthPath[] = "/var/run/x11.auth";
// Path to the app_shell binary.
const char kAppShellPath[] = "/opt/google/chrome/app_shell";
// Directory where data files are written at build time.
const char kReadonlyDataPath[] = "/usr/share/app_shell";
// Subdirectory under $DATA_DIR where user data should be stored.
const char kUserSubdir[] = "user";
// Files in $DATA_DIR or kReadonlyDataPath containing the ID of the app that
// should be loaded and the name of a preferred network to connect to.
const char kAppIdFile[] = "app_id";
const char kPreferredNetworkFile[] = "preferred_network";
// Subdirectory under $DATA_DIR or kReadonlyDataPath from which an app is loaded
// if kAppIdFile doesn't exist.
const char kAppSubdir[] = "app";
// Returns the first of the following paths that exists:
// - a file named |filename| within |stateful_dir|
// - a file named |filename| within |readonly_dir|
// - failing that, an empty path
base::FilePath GetDataPath(const base::FilePath& stateful_dir,
const base::FilePath& readonly_dir,
const std::string& filename) {
base::FilePath stateful_path = stateful_dir.Append(filename);
if (base::PathExists(stateful_path))
return stateful_path;
base::FilePath readonly_path = readonly_dir.Append(filename);
if (base::PathExists(readonly_path))
return readonly_path;
return base::FilePath();
// Calls GetDataPath() and reads the file to |data_out|.
// Returns true on success.
bool ReadData(const base::FilePath& stateful_dir,
const base::FilePath& readonly_dir,
const std::string& filename,
std::string* data_out) {
base::FilePath path = GetDataPath(stateful_dir, readonly_dir, filename);
return !path.empty() ? base::ReadFileToString(path, data_out) : false;
// Adds app_shell-specific flags.
void AddAppShellFlags(ChromiumCommandBuilder* builder) {
const base::FilePath stateful_dir(builder->ReadEnvVar("DATA_DIR"));
const base::FilePath readonly_dir(kReadonlyDataPath);
// Set --data-path to tell app_shell where to store user data.
const base::FilePath user_path = stateful_dir.Append(kUserSubdir);
CHECK(EnsureDirectoryExists(user_path, builder->uid(), builder->gid(), 0700));
builder->AddArg("--data-path=" + user_path.value());
std::string app_id;
if (ReadData(stateful_dir, readonly_dir, kAppIdFile, &app_id)) {
base::TrimWhitespaceASCII(app_id, base::TRIM_ALL, &app_id);
builder->AddArg("--app-shell-app-id=" + app_id);
} else {
const base::FilePath app_path =
GetDataPath(stateful_dir, readonly_dir, kAppSubdir);
if (!app_path.empty())
builder->AddArg("--app-shell-app-path=" + app_path.value());
std::string network;
if (ReadData(stateful_dir, readonly_dir, kPreferredNetworkFile, &network)) {
base::TrimWhitespaceASCII(network, base::TRIM_ALL, &network);
builder->AddArg("--app-shell-preferred-network=" + network);
// Replaces the currently-running process with app_shell.
void ExecAppShell(const ChromiumCommandBuilder& builder) {
if (setpriority(PRIO_PROCESS, 0, -20) != 0)
PLOG(WARNING) << "setpriority() failed";
PCHECK(initgroups(ChromiumCommandBuilder::kUser, builder.gid()) == 0);
PCHECK(setgid(builder.gid()) == 0);
PCHECK(setuid(builder.uid()) == 0);
PCHECK(clearenv() == 0);
for (ChromiumCommandBuilder::StringMap::const_iterator it =
it != builder.environment_variables().end(); ++it) {
PCHECK(setenv(it->first.c_str(), it->second.c_str(), 1) == 0);
const size_t kMaxArgs = 64;
CHECK_LE(builder.arguments().size(), kMaxArgs);
// One extra pointer for the initial command and one for the terminating NULL.
char* argv[kMaxArgs + 2];
for (size_t i = 0; i < arraysize(argv); ++i)
argv[i] = nullptr;
argv[0] = const_cast<char*>(kAppShellPath);
for (size_t i = 0; i < builder.arguments().size(); ++i)
argv[i + 1] = const_cast<char*>(builder.arguments()[i].c_str());
PCHECK(execv(argv[0], argv) == 0);
} // namespace
int main(int argc, char** argv) {
ChromiumCommandBuilder builder;
// Start the X server in the background before doing more-expensive setup.
scoped_ptr<XServerRunner> x_runner;
const base::FilePath xauth_path(kXauthPath);
const bool using_x11 = builder.UseFlagIsSet("X");
if (using_x11) {
x_runner.reset(new XServerRunner);
XServerRunner::kDefaultUser, XServerRunner::kDefaultVt,
builder.is_developer_end_user(), xauth_path));
builder.SetUpChromium(using_x11 ? xauth_path : base::FilePath());
if (using_x11)
// Do not add setup code below this point. Potentially-expensive work should
// be done between StartServer() and WaitForServer().
// This call never returns.
return 1;