/* Disk protection for HP machines.
   *
   * Copyright 2008 Eric Piel

   * Copyright 2009 Pavel Machek <pavel@ucw.cz>

   *
   * GPLv2.
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <string.h>
  #include <stdint.h>
  #include <errno.h>
  #include <signal.h>

  #include <sys/mman.h>
  #include <sched.h>

  char unload_heads_path[64];
  
  int set_unload_heads_path(char *device)
  {
  	char devname[64];
  
  	if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
  		return -EINVAL;
  	strncpy(devname, device + 5, sizeof(devname));
  
  	snprintf(unload_heads_path, sizeof(unload_heads_path),
  				"/sys/block/%s/device/unload_heads", devname);
  	return 0;
  }
  int valid_disk(void)
  {
  	int fd = open(unload_heads_path, O_RDONLY);
  	if (fd < 0) {
  		perror(unload_heads_path);
  		return 0;
  	}
  
  	close(fd);
  	return 1;
  }

  void write_int(char *path, int i)
  {
  	char buf[1024];
  	int fd = open(path, O_RDWR);
  	if (fd < 0) {
  		perror("open");
  		exit(1);
  	}
  	sprintf(buf, "%d", i);
  	if (write(fd, buf, strlen(buf)) != strlen(buf)) {
  		perror("write");
  		exit(1);
  	}
  	close(fd);
  }
  
  void set_led(int on)
  {
  	write_int("/sys/class/leds/hp::hddprotect/brightness", on);
  }
  
  void protect(int seconds)
  {

  	write_int(unload_heads_path, seconds*1000);

  }
  
  int on_ac(void)
  {
  //	/sys/class/power_supply/AC0/online
  }
  
  int lid_open(void)
  {
  //	/proc/acpi/button/lid/LID/state
  }
  
  void ignore_me(void)
  {
  	protect(0);
  	set_led(0);

  }

  int main(int argc, char **argv)

  {

  	int fd, ret;

  	struct sched_param param;

  	if (argc == 1)
  		ret = set_unload_heads_path("/dev/sda");
  	else if (argc == 2)
  		ret = set_unload_heads_path(argv[1]);
  	else
  		ret = -EINVAL;
  
  	if (ret || !valid_disk()) {
  		fprintf(stderr, "usage: %s <device> (default: /dev/sda)
  ",
  				argv[0]);
  		exit(1);
  	}

  	fd = open("/dev/freefall", O_RDONLY);
  	if (fd < 0) {

  		perror("/dev/freefall");

  		return EXIT_FAILURE;
  	}

  	daemon(0, 0);
  	param.sched_priority = sched_get_priority_max(SCHED_FIFO);
  	sched_setscheduler(0, SCHED_FIFO, &param);
  	mlockall(MCL_CURRENT|MCL_FUTURE);

  	signal(SIGALRM, ignore_me);

  	for (;;) {
  		unsigned char count;
  
  		ret = read(fd, &count, sizeof(count));
  		alarm(0);
  		if ((ret == -1) && (errno == EINTR)) {
  			/* Alarm expired, time to unpark the heads */
  			continue;
  		}
  
  		if (ret != sizeof(count)) {
  			perror("read");
  			break;
  		}
  
  		protect(21);
  		set_led(1);
  		if (1 || on_ac() || lid_open())
  			alarm(2);
  		else
  			alarm(20);
  	}

  	close(fd);
  	return EXIT_SUCCESS;

  }