unplugged-system/system/apex/apexd/apexd_main.cpp

/*
 * 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.
 */

#define LOG_TAG "apexd"

#include <strings.h>
#include <sys/stat.h>

#include <ApexProperties.sysprop.h>
#include <android-base/logging.h>

#include "apexd.h"
#include "apexd_checkpoint_vold.h"
#include "apexd_lifecycle.h"
#include "apexservice.h"

#include <android-base/properties.h>

#define APEXD_LOG_UNLIMIT
#ifdef  APEXD_LOG_UNLIMIT
#include <fcntl.h>
#include <android-base/chrono_utils.h>
#include <android-base/parseint.h>
using android::base::boot_clock;
#include <utils/Mutex.h>
#endif //APEXD_LOG_UNLIMIT

namespace {

using android::base::SetDefaultTag;

int HandleSubcommand(char** argv) {
  if (strcmp("--bootstrap", argv[1]) == 0) {
    SetDefaultTag("apexd-bootstrap");
    LOG(INFO) << "Bootstrap subcommand detected";
    return android::apex::OnBootstrap();
  }

  if (strcmp("--unmount-all", argv[1]) == 0) {
    SetDefaultTag("apexd-unmount-all");
    LOG(INFO) << "Unmount all subcommand detected";
    return android::apex::UnmountAll();
  }

  if (strcmp("--otachroot-bootstrap", argv[1]) == 0) {
    SetDefaultTag("apexd-otachroot");
    LOG(INFO) << "OTA chroot bootstrap subcommand detected";
    return android::apex::OnOtaChrootBootstrap();
  }

  if (strcmp("--snapshotde", argv[1]) == 0) {
    SetDefaultTag("apexd-snapshotde");
    LOG(INFO) << "Snapshot DE subcommand detected";
    // Need to know if checkpointing is enabled so that a prerestore snapshot
    // can be taken if it's not.
    android::base::Result<android::apex::VoldCheckpointInterface>
        vold_service_st = android::apex::VoldCheckpointInterface::Create();
    if (!vold_service_st.ok()) {
      LOG(ERROR) << "Could not retrieve vold service: "
                 << vold_service_st.error();
    } else {
      android::apex::InitializeVold(&*vold_service_st);
    }

    int result = android::apex::SnapshotOrRestoreDeUserData();

    if (result == 0) {
      // Notify other components (e.g. init) that all APEXs are ready to be used
      // Note that it's important that the binder service is registered at this
      // point, since other system services might depend on it.
      android::apex::OnAllPackagesReady();
    }
    return result;
  }

  if (strcmp("--vm", argv[1]) == 0) {
    SetDefaultTag("apexd-vm");
    LOG(INFO) << "VM subcommand detected";
    return android::apex::OnStartInVmMode();
  }

  LOG(ERROR) << "Unknown subcommand: " << argv[1];
  return 1;
}

void InstallSigtermSignalHandler() {
  struct sigaction action = {};
  action.sa_handler = [](int /*signal*/) {
    // Handle SIGTERM gracefully.
    // By default, when SIGTERM is received a process will exit with non-zero
    // exit code, which will trigger reboot_on_failure handler if one is
    // defined. This doesn't play well with userspace reboot which might
    // terminate apexd with SIGTERM if apexd was running at the moment of
    // userspace reboot, hence this custom handler to exit gracefully.
    _exit(0);
  };
  sigaction(SIGTERM, &action, nullptr);
}

}  // namespace

#ifdef  APEXD_LOG_UNLIMIT
#if defined(__linux__)

static int kmsg_fd_ulimit = -1;
static uint64_t log_time;
static unsigned int log_printed = 0;
#define DEFAULT_RATELIMIT_INTERVALMS 5000
#define DEFAULT_RATELIMIT_BURST 9
static android::Mutex kmsg_mutex;

static int OpenKmsg_ulimit() {
  android::Mutex::Autolock _l(kmsg_mutex);

  uint64_t nowms = std::chrono::duration_cast<std::chrono::milliseconds>(boot_clock::now().time_since_epoch()).count();

  if (kmsg_fd_ulimit == -1) {
    kmsg_fd_ulimit = TEMP_FAILURE_RETRY(open("/dev/kmsg", O_WRONLY | O_CLOEXEC));
    log_time = nowms;
    log_printed = 0;
  }

  if (log_printed >= DEFAULT_RATELIMIT_BURST) {
    int newfd;
    newfd = TEMP_FAILURE_RETRY(open("/dev/kmsg", O_WRONLY | O_CLOEXEC));

    if (newfd >= 0) {
       close(kmsg_fd_ulimit);
       kmsg_fd_ulimit = newfd;
       log_time = nowms;
       log_printed = 0;
    }
  }
  if (nowms >= log_time + DEFAULT_RATELIMIT_INTERVALMS) {
    log_time = nowms;
    log_printed = 0;
  }

  log_printed++;

  return kmsg_fd_ulimit;
}

static void KernelLogLine_ulimit(const char* msg, int length, android::base::LogSeverity severity,
                          const char* tag) {
  // clang-format off
  static constexpr int kLogSeverityToKernelLogLevel[] = {
      [android::base::VERBOSE] = 7,              // KERN_DEBUG (there is no verbose kernel log
                                                 //             level)
      [android::base::DEBUG] = 7,                // KERN_DEBUG
      [android::base::INFO] = 6,                 // KERN_INFO
      [android::base::WARNING] = 4,              // KERN_WARNING
      [android::base::ERROR] = 3,                // KERN_ERROR
      [android::base::FATAL_WITHOUT_ABORT] = 2,  // KERN_CRIT
      [android::base::FATAL] = 2,                // KERN_CRIT
  };
  // clang-format on
  static_assert(arraysize(kLogSeverityToKernelLogLevel) == android::base::FATAL + 1,
                "Mismatch in size of kLogSeverityToKernelLogLevel and values in LogSeverity");

  int klog_fd = OpenKmsg_ulimit();
  if (klog_fd == -1) return;

  int level = kLogSeverityToKernelLogLevel[severity];

  // The kernel's printk buffer is only |1024 - PREFIX_MAX| bytes, where
  // PREFIX_MAX could be 48 or 32.
  // Reference: kernel/printk/printk.c
  static constexpr int LOG_LINE_MAX = 1024 - 48;
  char buf[LOG_LINE_MAX] __attribute__((__uninitialized__));
  size_t size = snprintf(buf, sizeof(buf), "<%d>%s: %.*s\n", level, tag, length, msg);
  TEMP_FAILURE_RETRY(write(klog_fd, buf, std::min(size, sizeof(buf))));

  if (size > sizeof(buf)) {
    size_t truncated = size - sizeof(buf);
    size = snprintf(
        buf, sizeof(buf),
        "<%d>%s: **previous message missing %zu bytes** %zu-byte message too long for printk\n",
        level, tag, truncated, size);
    TEMP_FAILURE_RETRY(write(klog_fd, buf, std::min(size, sizeof(buf))));
  }
}

template <typename F, typename... Args>
static void SplitByLines_ulimit(const char* msg, const F& log_function, Args&&... args) {
  const char* newline = strchr(msg, '\n');
  while (newline != nullptr) {
    log_function(msg, newline - msg, args...);
    msg = newline + 1;
    newline = strchr(msg, '\n');
  }

  log_function(msg, -1, args...);
}

void KernelLogger_ulimit(android::base::LogId, android::base::LogSeverity severity, const char* tag,
                  const char*, unsigned int, const char* full_message) {
  SplitByLines_ulimit(full_message, KernelLogLine_ulimit, severity, tag);
}
#endif //defined(__linux__)
#endif //APEXD_LOG_UNLIMIT

int main(int /*argc*/, char** argv) {
#ifndef APEXD_LOG_UNLIMIT
  android::base::InitLogging(argv, &android::base::KernelLogger);
#else
  android::base::InitLogging(argv, &KernelLogger_ulimit);
#endif //APEXD_LOG_UNLIMIT
  // TODO(b/158468454): add a -v flag or an external setting to change severity.
  android::base::SetMinimumLogSeverity(android::base::INFO);

  // set umask to 022 so that files/dirs created are accessible to other
  // processes e.g.) /apex/apex-info-list.xml is supposed to be read by other
  // processes
  umask(022);

  InstallSigtermSignalHandler();

  android::apex::SetConfig(android::apex::kDefaultConfig);

  android::apex::ApexdLifecycle& lifecycle =
      android::apex::ApexdLifecycle::GetInstance();
  bool booting = lifecycle.IsBooting();

  const bool has_subcommand = argv[1] != nullptr;
  if (!android::sysprop::ApexProperties::updatable().value_or(false)) {
    if (!has_subcommand) {
      if (!booting) {
        // We've finished booting, but for some reason somebody tried to start
        // apexd. Simply exit.
        return 0;
      }

      LOG(INFO) << "This device does not support updatable APEX. Exiting";
      // Mark apexd as activated so that init can proceed.
      android::apex::OnAllPackagesActivated(/*is_bootstrap=*/false);
    } else if (strcmp("--snapshotde", argv[1]) == 0) {
      LOG(INFO) << "This device does not support updatable APEX. Exiting";
      // mark apexd as ready
      android::apex::OnAllPackagesReady();
    } else if (strcmp("--otachroot-bootstrap", argv[1]) == 0) {
      SetDefaultTag("apexd-otachroot");
      LOG(INFO) << "OTA chroot bootstrap subcommand detected";
      return android::apex::ActivateFlattenedApex();
    } else if (strcmp("--bootstrap", argv[1]) == 0) {
      LOG(INFO) << "Bootstrap subcommand detected";
      return android::apex::ActivateFlattenedApex();
    }
    return 0;
  }

  if (has_subcommand) {
    return HandleSubcommand(argv);
  }

  android::base::Result<android::apex::VoldCheckpointInterface>
      vold_service_st = android::apex::VoldCheckpointInterface::Create();
  android::apex::VoldCheckpointInterface* vold_service = nullptr;
  if (!vold_service_st.ok()) {
    LOG(ERROR) << "Could not retrieve vold service: "
               << vold_service_st.error();
  } else {
    vold_service = &*vold_service_st;
  }
  android::apex::Initialize(vold_service);

  if (booting) {
    if (auto res = android::apex::MigrateSessionsDirIfNeeded(); !res.ok()) {
      LOG(ERROR) << "Failed to migrate sessions to /metadata partition : "
                 << res.error();
    }
    android::apex::OnStart();
  } else {
    // TODO(b/172911822): Trying to use data apex related ApexFileRepository
    //  apis without initializing it should throw error. Also, unit tests should
    //  not pass without initialization.
    // TODO(b/172911822): Consolidate this with Initialize() when
    //  ApexFileRepository can act as cache and re-scanning is not expensive
    android::apex::InitializeDataApex();
  }
  // start apexservice before ApexdLifecycle::WaitForBootStatus which waits for
  // IApexService::markBootComplete().
  android::apex::binder::CreateAndRegisterService();
  android::apex::binder::StartThreadPool();

  if (booting) {
    // Notify other components (e.g. init) that all APEXs are correctly mounted
    // and activated (but are not yet ready to be used). Configuration based on
    // activated APEXs may be performed at this point, but use of APEXs
    // themselves should wait for the ready status instead, which is set when
    // the "--snapshotde" subcommand is received and snapshot/restore is
    // complete.
    android::apex::OnAllPackagesActivated(/*is_bootstrap=*/false);
    lifecycle.WaitForBootStatus(android::apex::RevertActiveSessionsAndReboot);
    // Run cleanup routine on boot complete.
    // This should run before AllowServiceShutdown() to prevent
    // service_manager killing apexd in the middle of the cleanup.
    android::apex::BootCompletedCleanup();
  }

  android::apex::binder::AllowServiceShutdown();

  android::apex::binder::JoinThreadPool();
  return 1;
}