/*
 * Copyright (C) 2012 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 "adb_install.h"

#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/unique_fd.h>

#include "common.h"
#include "fuse_sideload.h"
#include "install.h"
#include "ui.h"

static void set_usb_driver(bool enabled) {
  // USB configfs doesn't use /s/c/a/a/enable.
  if (android::base::GetBoolProperty("sys.usb.configfs", false)) {
    return;
  }

  static constexpr const char* USB_DRIVER_CONTROL = "/sys/class/android_usb/android0/enable";
  android::base::unique_fd fd(open(USB_DRIVER_CONTROL, O_WRONLY));
  if (fd == -1) {
    PLOG(ERROR) << "Failed to open driver control";
    return;
  }
  // Not using android::base::WriteStringToFile since that will open with O_CREAT and give EPERM
  // when USB_DRIVER_CONTROL doesn't exist. When it gives EPERM, we don't know whether that's due
  // to non-existent USB_DRIVER_CONTROL or indeed a permission issue.
  if (!android::base::WriteStringToFd(enabled ? "1" : "0", fd)) {
    PLOG(ERROR) << "Failed to set driver control";
  }
}

static void stop_adbd() {
  ui->Print("Stopping adbd...\n");
  android::base::SetProperty("ctl.stop", "adbd");
  set_usb_driver(false);
}

static void maybe_restart_adbd() {
  if (is_ro_debuggable()) {
    ui->Print("Restarting adbd...\n");
    set_usb_driver(true);
    android::base::SetProperty("ctl.start", "adbd");
  }
}

int apply_from_adb(bool* wipe_cache) {
  modified_flash = true;

  stop_adbd();
  set_usb_driver(true);

  ui->Print(
      "\n\nNow send the package you want to apply\n"
      "to the device with \"adb sideload <filename>\"...\n");

  pid_t child;
  if ((child = fork()) == 0) {
    execl("/sbin/recovery", "recovery", "--adbd", nullptr);
    _exit(EXIT_FAILURE);
  }

  // How long (in seconds) we wait for the host to start sending us a package, before timing out.
  static constexpr int ADB_INSTALL_TIMEOUT = 300;

  // FUSE_SIDELOAD_HOST_PATHNAME will start to exist once the host connects and starts serving a
  // package. Poll for its appearance. (Note that inotify doesn't work with FUSE.)
  int result = INSTALL_ERROR;
  int status;
  bool waited = false;
  for (int i = 0; i < ADB_INSTALL_TIMEOUT; ++i) {
    if (waitpid(child, &status, WNOHANG) != 0) {
      result = INSTALL_ERROR;
      waited = true;
      break;
    }

    struct stat st;
    if (stat(FUSE_SIDELOAD_HOST_PATHNAME, &st) != 0) {
      if (errno == ENOENT && i < ADB_INSTALL_TIMEOUT - 1) {
        sleep(1);
        continue;
      } else {
        ui->Print("\nTimed out waiting for package.\n\n");
        result = INSTALL_ERROR;
        kill(child, SIGKILL);
        break;
      }
    }
    result = install_package(FUSE_SIDELOAD_HOST_PATHNAME, wipe_cache, false, 0);
    break;
  }

  if (!waited) {
    // Calling stat() on this magic filename signals the minadbd subprocess to shut down.
    struct stat st;
    stat(FUSE_SIDELOAD_HOST_EXIT_PATHNAME, &st);

    // TODO: there should be a way to cancel waiting for a package (by pushing some button combo on
    // the device). For now you just have to 'adb sideload' a file that's not a valid package, like
    // "/dev/null".
    waitpid(child, &status, 0);
  }

  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
    if (WEXITSTATUS(status) == 3) {
      ui->Print("\nYou need adb 1.0.32 or newer to sideload\nto this device.\n\n");
    } else if (!WIFSIGNALED(status)) {
      ui->Print("\n(adbd status %d)\n", WEXITSTATUS(status));
    }
  }

  set_usb_driver(false);
  maybe_restart_adbd();

  return result;
}