host/commands/assemble_cvd/boot_config.cc

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "host/commands/assemble_cvd/boot_config.h"

#include <fstream>
#include <sstream>
#include <string>

#include <sys/stat.h>

#include <android-base/logging.h>
#include <android-base/strings.h>
#include <gflags/gflags.h>

#include "common/libs/utils/environment.h"
#include "common/libs/utils/files.h"
#include "common/libs/utils/size_utils.h"
#include "common/libs/utils/subprocess.h"
#include "host/libs/config/bootconfig_args.h"
#include "host/libs/config/cuttlefish_config.h"
#include "host/libs/config/kernel_args.h"
#include "host/libs/vm_manager/crosvm_manager.h"
#include "host/libs/vm_manager/vm_manager.h"

using cuttlefish::vm_manager::CrosvmManager;

DECLARE_bool(pause_in_bootloader);
DECLARE_string(vm_manager);

// Taken from external/avb/avbtool.py; this define is not in the headers
#define MAX_AVB_METADATA_SIZE 69632ul

namespace cuttlefish {
namespace {

size_t WriteEnvironment(const CuttlefishConfig& config,
                        const std::string& kernel_args,
                        const std::string& env_path) {
  std::ostringstream env;

  if (!kernel_args.empty()) {
    env << "uenvcmd=setenv bootargs \"$cbootargs " << kernel_args << "\" && ";
  } else {
    env << "uenvcmd=setenv bootargs \"$cbootargs\" && ";
  }
  if (FLAGS_pause_in_bootloader) {
    env << "if test $paused -ne 1; then paused=1; else run bootcmd_android; fi";
  } else {
    env << "run bootcmd_android";
  }
  env << '\0';
  if (!config.boot_slot().empty()) {
    env << "android_slot_suffix=_" << config.boot_slot() << '\0';
  }
  env << '\0';

  std::string env_str = env.str();
  std::ofstream file_out(env_path.c_str(), std::ios::binary);
  file_out << env_str;

  if (!file_out.good()) {
    return 0;
  }

  return env_str.length();
}

}  // namespace

class InitBootloaderEnvPartitionImpl : public InitBootloaderEnvPartition {
 public:
  INJECT(InitBootloaderEnvPartitionImpl(
      const CuttlefishConfig& config,
      const CuttlefishConfig::InstanceSpecific& instance))
      : config_(config), instance_(instance) {}

  // SetupFeature
  std::string Name() const override { return "InitBootloaderEnvPartitionImpl"; }
  bool Enabled() const override { return !config_.protected_vm(); }

 private:
  std::unordered_set<SetupFeature*> Dependencies() const override { return {}; }
  bool Setup() override {
    auto boot_env_image_path = instance_.uboot_env_image_path();
    auto tmp_boot_env_image_path = boot_env_image_path + ".tmp";
    auto uboot_env_path = instance_.PerInstancePath("mkenvimg_input");
    auto kernel_cmdline =
        android::base::Join(KernelCommandLineFromConfig(config_), " ");
    // If the bootconfig isn't supported in the guest kernel, the bootconfig
    // args need to be passed in via the uboot env. This won't be an issue for
    // protect kvm which is running a kernel with bootconfig support.
    if (!config_.bootconfig_supported()) {
      auto bootconfig_args = android::base::Join(
          BootconfigArgsFromConfig(config_, instance_), " ");
      // "androidboot.hardware" kernel parameter has changed to "hardware" in
      // bootconfig and needs to be replaced before being used in the kernel
      // cmdline.
      bootconfig_args = android::base::StringReplace(
          bootconfig_args, " hardware=", " androidboot.hardware=", true);
      // TODO(b/182417593): Until we pass the module parameters through
      // modules.options, we pass them through bootconfig using
      // 'kernel.<key>=<value>' But if we don't support bootconfig, we need to
      // rename them back to the old cmdline version
      bootconfig_args =
          android::base::StringReplace(bootconfig_args, " kernel.", " ", true);
      kernel_cmdline += " ";
      kernel_cmdline += bootconfig_args;
    }
    if (!WriteEnvironment(config_, kernel_cmdline, uboot_env_path)) {
      LOG(ERROR) << "Unable to write out plaintext env '" << uboot_env_path
                 << ".'";
      return false;
    }

    auto mkimage_path = HostBinaryPath("mkenvimage_slim");
    Command cmd(mkimage_path);
    cmd.AddParameter("-output_path");
    cmd.AddParameter(tmp_boot_env_image_path);
    cmd.AddParameter("-input_path");
    cmd.AddParameter(uboot_env_path);
    int success = cmd.Start().Wait();
    if (success != 0) {
      LOG(ERROR) << "Unable to run mkenvimage_slim. Exited with status "
                 << success;
      return false;
    }

    const off_t boot_env_size_bytes = AlignToPowerOf2(
        MAX_AVB_METADATA_SIZE + 4096, PARTITION_SIZE_SHIFT);

    auto avbtool_path = HostBinaryPath("avbtool");
    Command boot_env_hash_footer_cmd(avbtool_path);
    boot_env_hash_footer_cmd.AddParameter("add_hash_footer");
    boot_env_hash_footer_cmd.AddParameter("--image");
    boot_env_hash_footer_cmd.AddParameter(tmp_boot_env_image_path);
    boot_env_hash_footer_cmd.AddParameter("--partition_size");
    boot_env_hash_footer_cmd.AddParameter(boot_env_size_bytes);
    boot_env_hash_footer_cmd.AddParameter("--partition_name");
    boot_env_hash_footer_cmd.AddParameter("uboot_env");
    boot_env_hash_footer_cmd.AddParameter("--key");
    boot_env_hash_footer_cmd.AddParameter(
        DefaultHostArtifactsPath("etc/cvd_avb_testkey.pem"));
    boot_env_hash_footer_cmd.AddParameter("--algorithm");
    boot_env_hash_footer_cmd.AddParameter("SHA256_RSA4096");
    success = boot_env_hash_footer_cmd.Start().Wait();
    if (success != 0) {
      LOG(ERROR) << "Unable to run append hash footer. Exited with status "
                 << success;
      return false;
    }

    if (!FileExists(boot_env_image_path) ||
        ReadFile(boot_env_image_path) != ReadFile(tmp_boot_env_image_path)) {
      if (!RenameFile(tmp_boot_env_image_path, boot_env_image_path)) {
        LOG(ERROR) << "Unable to delete the old env image.";
        return false;
      }
      LOG(DEBUG) << "Updated bootloader environment image.";
    } else {
      RemoveFile(tmp_boot_env_image_path);
    }

    return true;
  }

  const CuttlefishConfig& config_;
  const CuttlefishConfig::InstanceSpecific& instance_;
};

fruit::Component<fruit::Required<const CuttlefishConfig,
                                 const CuttlefishConfig::InstanceSpecific>,
                 InitBootloaderEnvPartition>
InitBootloaderEnvPartitionComponent() {
  return fruit::createComponent()
      .bind<InitBootloaderEnvPartition, InitBootloaderEnvPartitionImpl>()
      .addMultibinding<SetupFeature, InitBootloaderEnvPartition>();
}

} // namespace cuttlefish