/*
 * This file is part of the Trezor project, https://trezor.io/
 *
 * Copyright (C) 2017 Saleem Rashid <trezor@saleemrashid.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>

#include <libopencm3/stm32/flash.h>

#include "memory.h"
#include "oled.h"
#include "rng.h"
#include "setup.h"
#include "timer.h"

#define EMULATOR_FLASH_FILE "emulator.img"

#ifndef RANDOM_DEV_FILE
#define RANDOM_DEV_FILE "/dev/urandom"
#endif

uint8_t *emulator_flash_base = NULL;

uint32_t __stack_chk_guard;

static int random_fd = -1;

static void setup_urandom(void);
static void setup_flash(void);

void setup(void) {
  setup_urandom();
  setup_flash();
}

void __attribute__((noreturn)) shutdown(void) {
  sleep(5);
  exit(4);
}

void emulatorRandom(void *buffer, size_t size) {
  ssize_t n = 0, len = 0;
  do {
    n = read(random_fd, (char *)buffer + len, size - len);
    if (n < 0) {
      perror("Failed to read " RANDOM_DEV_FILE);
      exit(1);
    }
    len += n;
  } while (len != (ssize_t)size);
}

static void setup_urandom(void) {
  random_fd = open(RANDOM_DEV_FILE, O_RDONLY);
  if (random_fd < 0) {
    perror("Failed to open " RANDOM_DEV_FILE);
    exit(1);
  }
}

static void setup_flash(void) {
  int fd = open(EMULATOR_FLASH_FILE, O_RDWR | O_SYNC | O_CREAT, 0644);
  if (fd < 0) {
    perror("Failed to open flash emulation file");
    exit(1);
  }

  off_t length = lseek(fd, 0, SEEK_END);
  if (length < 0) {
    perror("Failed to read length of flash emulation file");
    exit(1);
  }

  emulator_flash_base =
      mmap(NULL, FLASH_TOTAL_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  if (emulator_flash_base == MAP_FAILED) {
    perror("Failed to map flash emulation file");
    exit(1);
  }

  if (length < FLASH_TOTAL_SIZE) {
    if (ftruncate(fd, FLASH_TOTAL_SIZE) != 0) {
      perror("Failed to initialize flash emulation file");
      exit(1);
    }

    /* Initialize the flash */
    flash_erase_all_sectors(FLASH_CR_PROGRAM_X32);
  }
}