// Copyright 2020 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 "services/device/hid/hid_service_fido.h"

#include <fcntl.h>
#include <poll.h>
#include <stdint.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

// TODO: remove once the missing guard in fido.h is fixed upstream.
extern "C" {
#include <fido.h>
}

#include <set>
#include <string>
#include <vector>

#include "base/bind.h"
#include "base/files/file.h"
#include "base/files/file_descriptor_watcher_posix.h"
#include "base/files/file_enumerator.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/posix/eintr_wrapper.h"
#include "base/task/thread_pool.h"
#include "base/single_thread_task_runner.h"
#include "base/stl_util.h"
#include "base/strings/pattern.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/sys_string_conversions.h"
#include "base/task/post_task.h"
#include "base/threading/scoped_blocking_call.h"
#include "base/threading/thread_task_runner_handle.h"
#include "components/device_event_log/device_event_log.h"
#include "services/device/hid/hid_connection_fido.h"

namespace device {

namespace {

struct ConnectParams {
  ConnectParams(scoped_refptr<HidDeviceInfo> device_info,
                HidService::ConnectCallback callback)
      : device_info(std::move(device_info)), callback(std::move(callback)),
        task_runner(base::ThreadTaskRunnerHandle::Get()),
        blocking_task_runner(base::ThreadPool::CreateSequencedTaskRunner(
            HidService::kBlockingTaskTraits)) {}
  ~ConnectParams() {}

  scoped_refptr<HidDeviceInfo> device_info;
  HidService::ConnectCallback callback;
  scoped_refptr<base::SequencedTaskRunner> task_runner;
  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner;
  base::ScopedFD fd;
};

void CreateConnection(std::unique_ptr<ConnectParams> params) {
  DCHECK(params->fd.is_valid());
  std::move(params->callback).Run(base::MakeRefCounted<HidConnectionFido>(
      std::move(params->device_info), std::move(params->fd),
      std::move(params->blocking_task_runner)));
}

void FinishOpen(std::unique_ptr<ConnectParams> params) {
  scoped_refptr<base::SequencedTaskRunner> task_runner = params->task_runner;

  task_runner->PostTask(FROM_HERE,
                        base::Bind(&CreateConnection, base::Passed(&params)));
}

bool terrible_ping_kludge(int fd, const std::string &path) {
  u_char data[256];
  int i, n;
  struct pollfd pfd;

  for (i = 0; i < 4; i++) {
    memset(data, 0, sizeof(data));
    /* broadcast channel ID */
    data[1] = 0xff;
    data[2] = 0xff;
    data[3] = 0xff;
    data[4] = 0xff;
    /* Ping command */
    data[5] = 0x81;
    /* One byte ping only, Vasili */
    data[6] = 0;
    data[7] = 1;
    HID_LOG(EVENT) << "send ping " << i << " " << path;
    if (write(fd, data, 64) == -1) {
      HID_PLOG(ERROR) << "write " << path;
      return false;
    }
    HID_LOG(EVENT) << "wait reply " << path;
    memset(&pfd, 0, sizeof(pfd));
    pfd.fd = fd;
    pfd.events = POLLIN;
    if ((n = poll(&pfd, 1, 100)) == -1) {
      HID_PLOG(EVENT) << "poll " << path;
      return false;
    } else if (n == 0) {
      HID_LOG(EVENT) << "timed out " << path;
      continue;
    }
    if (read(fd, data, 64) == -1) {
      HID_PLOG(ERROR) << "read " << path;
      return false;
    }
    /*
     * Ping isn't always supported on the broadcast channel,
     * so we might get an error, but we don't care - we're
     * synched now.
     */
    HID_LOG(EVENT) << "got reply " << path;
    return true;
  }
  HID_LOG(ERROR) << "no response " << path;
  return false;
}

void OpenOnBlockingThread(std::unique_ptr<ConnectParams> params) {
  base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
                                                base::BlockingType::MAY_BLOCK);
  scoped_refptr<base::SequencedTaskRunner> task_runner = params->task_runner;

  const auto &device_node = params->device_info->device_node();
  base::FilePath device_path(device_node);
  int flags =
      base::File::FLAG_OPEN | base::File::FLAG_READ | base::File::FLAG_WRITE;
  base::File device_file(device_path, flags);
  if (!device_file.IsValid()) {
    HID_LOG(EVENT) << "Failed to open '" << device_node << "': "
                   << base::File::ErrorToString(device_file.error_details());
    task_runner->PostTask(FROM_HERE, base::BindOnce(std::move(params->callback), nullptr));
    return;
  }
  if (!terrible_ping_kludge(device_file.GetPlatformFile(), device_node)) {
    HID_LOG(EVENT) << "Failed to ping " << device_node;
    task_runner->PostTask(FROM_HERE, base::BindOnce(std::move(params->callback), nullptr));
    return;
  }
  params->fd.reset(device_file.TakePlatformFile());
  FinishOpen(std::move(params));
}

// HID report descriptor for U2F interface. Copied from:
// https://chromium.googlesource.com/chromiumos/platform2/+/c6c7e4e54fce11932fedaa3ea10236bf75d85a2b%5E%21/u2fd/u2fhid.cc
// Apparently Chromium wants to see these bytes, but OpenBSD fido(4)
// devices prohibit USB_GET_REPORT_DESC ioctl that could be used to
// get the bytes from the USB device.
constexpr uint8_t kU2fReportDesc[] = {
    0x06, 0xD0, 0xF1, /* Usage Page (FIDO Alliance), FIDO_USAGE_PAGE */
    0x09, 0x01,       /* Usage (U2F HID Auth. Device) FIDO_USAGE_U2FHID */
    0xA1, 0x01,       /* Collection (Application), HID_APPLICATION */
    0x09, 0x20,       /*  Usage (Input Report Data), FIDO_USAGE_DATA_IN */
    0x15, 0x00,       /*  Logical Minimum (0) */
    0x26, 0xFF, 0x00, /*  Logical Maximum (255) */
    0x75, 0x08,       /*  Report Size (8) */
    0x95, 0x40,       /*  Report Count (64), HID_INPUT_REPORT_BYTES */
    0x81, 0x02,       /*  Input (Data, Var, Abs), Usage */
    0x09, 0x21,       /*  Usage (Output Report Data), FIDO_USAGE_DATA_OUT */
    0x15, 0x00,       /*  Logical Minimum (0) */
    0x26, 0xFF, 0x00, /*  Logical Maximum (255) */
    0x75, 0x08,       /*  Report Size (8) */
    0x95, 0x40,       /*  Report Count (64), HID_OUTPUT_REPORT_BYTES */
    0x91, 0x02,       /*  Output (Data, Var, Abs), Usage */
    0xC0              /* End Collection */
};

} // namespace

class HidServiceFido::BlockingTaskHelper {
public:
  BlockingTaskHelper(base::WeakPtr<HidServiceFido> service)
      : service_(std::move(service)),
        task_runner_(base::ThreadTaskRunnerHandle::Get()) {
    DETACH_FROM_SEQUENCE(sequence_checker_);
  }

  ~BlockingTaskHelper() = default;

  void Start() {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    base::ScopedBlockingCall scoped_blocking_call(
        FROM_HERE, base::BlockingType::MAY_BLOCK);

    fido_dev_info_t *devlist = NULL;
    fido_dev_t *dev = NULL;
    size_t devlist_len = 0, i;
    const char *path;
    int r;
    const int MAX_FIDO_DEVICES = 256;

    if ((devlist = fido_dev_info_new(MAX_FIDO_DEVICES)) == NULL) {
      HID_LOG(ERROR) << "fido_dev_info_new failed";
      goto out;
    }
    if ((r = fido_dev_info_manifest(devlist, MAX_FIDO_DEVICES, &devlist_len)) !=
        FIDO_OK) {
      HID_LOG(ERROR) << "fido_dev_info_manifest: " << fido_strerr(r);
      goto out;
    }

    HID_LOG(EVENT) << "fido_dev_info_manifest found " << devlist_len
                   << " device(s)";

    for (i = 0; i < devlist_len; i++) {
      const fido_dev_info_t *di = fido_dev_info_ptr(devlist, i);
      if (di == NULL) {
        HID_LOG(ERROR) << "fido_dev_info_ptr " << i << " failed";
        continue;
      }
      if ((path = fido_dev_info_path(di)) == NULL) {
        HID_LOG(ERROR) << "fido_dev_info_path " << i << " failed";
        continue;
      }
      HID_LOG(EVENT) << "trying device " << i << ": " << path;
      if ((dev = fido_dev_new()) == NULL) {
        HID_LOG(ERROR) << "fido_dev_new failed";
        continue;
      }
      if ((r = fido_dev_open(dev, path)) != FIDO_OK) {
        HID_LOG(ERROR) << "fido_dev_open failed " << path;
        fido_dev_free(&dev);
        continue;
      }
      OnDeviceAdded(di);
      fido_dev_close(dev);
      fido_dev_free(&dev);
    }

  out:
    if (devlist != NULL)
      fido_dev_info_free(&devlist, MAX_FIDO_DEVICES);

    task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&HidServiceFido::FirstEnumerationComplete, service_));
  }

  void OnDeviceAdded(const fido_dev_info_t *di) {
    auto null_as_empty = [](const char *r) -> std::string {
      return (r != nullptr) ? r : "";
    };
    std::string device_node(null_as_empty(fido_dev_info_path(di)));
    std::vector<uint8_t> report_descriptor(
        kU2fReportDesc, kU2fReportDesc + sizeof(kU2fReportDesc));
    scoped_refptr<HidDeviceInfo> device_info(new HidDeviceInfo(
        device_node, /*physical_device_id=*/"", fido_dev_info_vendor(di),
        fido_dev_info_product(di), null_as_empty(fido_dev_info_product_string(di)),
        null_as_empty(fido_dev_info_manufacturer_string(di)),
        device::mojom::HidBusType::kHIDBusTypeUSB, report_descriptor,
        device_node));

    task_runner_->PostTask(FROM_HERE, base::Bind(&HidServiceFido::AddDevice,
                                                 service_, device_info));
  }

  void OnDeviceRemoved(std::string device_node) {
    base::ScopedBlockingCall scoped_blocking_call(
        FROM_HERE, base::BlockingType::MAY_BLOCK);
    task_runner_->PostTask(FROM_HERE, base::Bind(&HidServiceFido::RemoveDevice,
                                                 service_, device_node));
  }

private:
  SEQUENCE_CHECKER(sequence_checker_);

  // This weak pointer is only valid when checked on this task runner.
  base::WeakPtr<HidServiceFido> service_;
  scoped_refptr<base::SequencedTaskRunner> task_runner_;

  DISALLOW_COPY_AND_ASSIGN(BlockingTaskHelper);
};

HidServiceFido::HidServiceFido()
    : task_runner_(base::ThreadTaskRunnerHandle::Get()),
      blocking_task_runner_(
          base::ThreadPool::CreateSequencedTaskRunner(kBlockingTaskTraits)),
      weak_factory_(this), helper_(std::make_unique<BlockingTaskHelper>(
                               weak_factory_.GetWeakPtr())) {
  blocking_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&BlockingTaskHelper::Start, base::Unretained(helper_.get())));
}

HidServiceFido::~HidServiceFido() {
  blocking_task_runner_->DeleteSoon(FROM_HERE, helper_.release());
}

base::WeakPtr<HidService> HidServiceFido::GetWeakPtr() {
  return weak_factory_.GetWeakPtr();
}

void HidServiceFido::Connect(const std::string &device_guid,
                             ConnectCallback callback) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);

  const auto &map_entry = devices().find(device_guid);
  if (map_entry == devices().end()) {
    base::ThreadTaskRunnerHandle::Get()->PostTask(
        FROM_HERE, base::BindOnce(std::move(callback), nullptr));
    return;
  }

  scoped_refptr<HidDeviceInfo> device_info = map_entry->second;

  auto params = std::make_unique<ConnectParams>(device_info, std::move(callback));

  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner =
      params->blocking_task_runner;
  blocking_task_runner->PostTask(
      FROM_HERE, base::Bind(&OpenOnBlockingThread, base::Passed(&params)));
}

} // namespace device