vbx/src/keyvibe_input.c

#include "utils.h"
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <fcntl.h>
#include <getopt.h>
#include <poll.h>
#include <pthread.h>
#include <unistd.h>

#include <libevdev/libevdev.h>
#include <libinput.h>
#include <libudev.h>

#include "config.h"

#define MAX_BUFFER_LENGTH 512

enum error_code {
  NO_ERROR,
  UDEV_FAILED,
  LIBINPUT_FAILED,
  SEAT_FAILED,
  PERMISSION_FAILED
};

struct input_handler_data {
  struct udev *udev;
  struct libinput *libinput;
};

static void *handle_input(void *user_data) {
  struct input_handler_data *input_handler_data = user_data;
  char line[MAX_BUFFER_LENGTH];
  while (fgets(line, MAX_BUFFER_LENGTH, stdin) != NULL) {
    if (strcmp(line, "stop\n") == 0) {
      libinput_unref(input_handler_data->libinput);
      udev_unref(input_handler_data->udev);
      exit(EXIT_SUCCESS);
    }
  }
  return NULL;
}

static int open_restricted(const char *path, int flags, void *user_data) {
  (void)user_data;
  int fd = open(path, flags);
  if (fd < 0)
    errorf("Failed to open %s because of %s.\n", path, strerror(errno));
  return fd < 0 ? -errno : fd;
}

static void close_restricted(int fd, void *user_data) {
  (void)user_data;
  close(fd);
}

static const struct libinput_interface interface = {
    .open_restricted = open_restricted, .close_restricted = close_restricted};

static int print_key_event(struct libinput_event *event) {
  struct libinput_event_keyboard *keyboard =
      libinput_event_get_keyboard_event(event);
  enum libinput_event_type event_type = libinput_event_get_type(event);
  uint32_t time_stamp = libinput_event_keyboard_get_time(keyboard);
  uint32_t key_code = libinput_event_keyboard_get_key(keyboard);
  const char *key_name = libevdev_event_code_get_name(EV_KEY, key_code);
  key_name = key_name ? key_name : "null";
  enum libinput_key_state state_code =
      libinput_event_keyboard_get_key_state(keyboard);
  const char *state_name =
      state_code == LIBINPUT_KEY_STATE_PRESSED ? "PRESSED" : "RELEASED";
  return printf("{\"event_name\": \"KEYBOARD_KEY\", \"event_type\": %d, "
                "\"time_stamp\": %d, \"key_name\": \"%s\", \"key_code\": %d, "
                "\"state_name\": \"%s\", \"state_code\": %d}\n",
                event_type, time_stamp, key_name, key_code, state_name,
                state_code);
}

static int print_button_event(struct libinput_event *event) {
  struct libinput_event_pointer *pointer =
      libinput_event_get_pointer_event(event);
  enum libinput_event_type event_type = libinput_event_get_type(event);
  uint32_t time_stamp = libinput_event_pointer_get_time(pointer);
  uint32_t button_code = libinput_event_pointer_get_button(pointer);
  const char *button_name = libevdev_event_code_get_name(EV_KEY, button_code);
  enum libinput_button_state state_code =
      libinput_event_pointer_get_button_state(pointer);
  const char *state_name =
      state_code == LIBINPUT_BUTTON_STATE_PRESSED ? "PRESSED" : "RELEASED";
  return printf("{\"event_name\": \"POINTER_BUTTON\", \"event_type\": %d, "
                "\"time_stamp\": %d, \"key_name\": \"%s\", \"key_code\": %d, "
                "\"state_name\": \"%s\", \"state_code\": %d}\n",
                event_type, time_stamp, button_name, button_code, state_name,
                state_code);
}

static int handle_events(struct libinput *libinput) {
  int result = -1;
  struct libinput_event *event;
  if (libinput_dispatch(libinput) < 0)
    return result;
  while ((event = libinput_get_event(libinput)) != NULL) {
    switch (libinput_event_get_type(event)) {
    case LIBINPUT_EVENT_KEYBOARD_KEY:
      print_key_event(event);
      break;
    case LIBINPUT_EVENT_POINTER_BUTTON:
      print_button_event(event);
      break;
    default:
      break;
    }
    fflush(stdout);
    libinput_event_destroy(event);
    result = 0;
  }
  return result;
}

static int run_mainloop(struct libinput *libinput) {
  struct pollfd fd;
  fd.fd = libinput_get_fd(libinput);
  fd.events = POLLIN;
  fd.revents = 0;
  if (handle_events(libinput) != 0)
    return errorf("Expected device added events on startup but got none. Maybe "
                  "you don't have the right permissions?\n");
  while (poll(&fd, 1, -1) > -1)
    handle_events(libinput);
  return 0;
}

void print_help(char *program_name) {
  printf("The backend of Show Me The Key.\n");
  printf("Version " PROJECT_VERSION ".\n");
  printf("Usage: %s [OPTION…]\n", program_name);
  printf("Options:\n");
  printf("\t-h, --help\tDisplay help then exit.\n");
  printf("\t-v, --version\tDisplay version then exit.\n");
  printf("Warning: This is the backend and is not designed to run by users. "
         "You should run the frontend of Show Me The Key, and the frontend "
         "will run this.\n");
}

int main(int argc, char *argv[]) {
  const struct option long_options[] = {{"version", no_argument, 0, 'v'},
                                        {"help", no_argument, 0, 'h'},
                                        {NULL, 0, NULL, 0}};
  int option_index = 0;
  int opt = 0;
  while ((opt = getopt_long(argc, argv, "vh", long_options, &option_index)) !=
         -1) {
    switch (opt) {
    case 0:
      break;
    case 'v':
      printf(PROJECT_VERSION "\n");
      return 0;
    case 'h':
      print_help(argv[0]);
      return 0;
    case '?':
      break;
    default:
      errorf("%s: Invalid option `-%c`.\n", argv[0], opt);
      break;
    }
  }
  struct udev *udev = udev_new();
  if (udev == NULL)
    return errorf("Failed to initialize udev.\n");
  struct libinput *libinput =
      libinput_udev_create_context(&interface, NULL, udev);
  if (!libinput)
    return errorf("Failed to initialize libinput from udev.\n");
  if (libinput_udev_assign_seat(libinput, "seat0") != 0) {
    errorf("Failed to set seat.\n");
    libinput_unref(libinput);
    udev_unref(udev);
    return SEAT_FAILED;
  }
  pthread_t input_handler;
  struct input_handler_data input_handler_data = {udev, libinput};
  pthread_create(&input_handler, NULL, handle_input, &input_handler_data);
  if (run_mainloop(libinput) < 0)
    return PERMISSION_FAILED;
  libinput_unref(libinput);
  udev_unref(udev);
  return NO_ERROR;
}