--- /dev/null
 +/* Disk protection for HP/DELL machines.
 + *
 + * Copyright 2008 Eric Piel
 + * Copyright 2009 Pavel Machek <pavel@ucw.cz>
 + * Copyright 2012 Sonal Santan
 + * Copyright 2014 Pali Rohár <pali.rohar@gmail.com>
 + *
 + * 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>
 +#include <syslog.h>
 +
 +static int noled;
 +static char unload_heads_path[64];
 +static char device_path[32];
 +static const char app_name[] = "FREE FALL";
 +
 +static 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) - 1);
++      devname[sizeof(devname) - 1] = '\0';
 +      strncpy(device_path, device, sizeof(device_path) - 1);
 +
 +      snprintf(unload_heads_path, sizeof(unload_heads_path) - 1,
 +                              "/sys/block/%s/device/unload_heads", devname);
 +      return 0;
 +}
 +
 +static 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;
 +}
 +
 +static 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);
 +}
 +
 +static void set_led(int on)
 +{
 +      if (noled)
 +              return;
 +      write_int("/sys/class/leds/hp::hddprotect/brightness", on);
 +}
 +
 +static void protect(int seconds)
 +{
 +      const char *str = (seconds == 0) ? "Unparked" : "Parked";
 +
 +      write_int(unload_heads_path, seconds*1000);
 +      syslog(LOG_INFO, "%s %s disk head\n", str, device_path);
 +}
 +
 +static int on_ac(void)
 +{
 +      /* /sys/class/power_supply/AC0/online */
 +      return 1;
 +}
 +
 +static int lid_open(void)
 +{
 +      /* /proc/acpi/button/lid/LID/state */
 +      return 1;
 +}
 +
 +static void ignore_me(int signum)
 +{
 +      protect(0);
 +      set_led(0);
 +}
 +
 +int main(int argc, char **argv)
 +{
 +      int fd, ret;
 +      struct stat st;
 +      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)\n",
 +                              argv[0]);
 +              exit(1);
 +      }
 +
 +      fd = open("/dev/freefall", O_RDONLY);
 +      if (fd < 0) {
 +              perror("/dev/freefall");
 +              return EXIT_FAILURE;
 +      }
 +
 +      if (stat("/sys/class/leds/hp::hddprotect/brightness", &st))
 +              noled = 1;
 +
 +      if (daemon(0, 0) != 0) {
 +              perror("daemon");
 +              return EXIT_FAILURE;
 +      }
 +
 +      openlog(app_name, LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
 +
 +      param.sched_priority = sched_get_priority_max(SCHED_FIFO);
 +      sched_setscheduler(0, SCHED_FIFO, ¶m);
 +      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);
 +      }
 +
 +      closelog();
 +      close(fd);
 +      return EXIT_SUCCESS;
 +}