Documentation/hwmon/hpfall.c

   1 /* Disk protection for HP machines.
   2  *
   3  * Copyright 2008 Eric Piel
   4  * Copyright 2009 Pavel Machek <pavel@suse.cz>
   5  *
   6  * GPLv2.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <unistd.h>
  12 #include <fcntl.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <string.h>
  16 #include <stdint.h>
  17 #include <errno.h>
  18 #include <signal.h>
  19
  20 void write_int(char *path, int i)
  21 {
  22         char buf[1024];
  23         int fd = open(path, O_RDWR);
  24         if (fd < 0) {
  25                 perror("open");
  26                 exit(1);
  27         }
  28         sprintf(buf, "%d", i);
  29         if (write(fd, buf, strlen(buf)) != strlen(buf)) {
  30                 perror("write");
  31                 exit(1);
  32         }
  33         close(fd);
  34 }
  35
  36 void set_led(int on)
  37 {
  38         write_int("/sys/class/leds/hp::hddprotect/brightness", on);
  39 }
  40
  41 void protect(int seconds)
  42 {
  43         write_int("/sys/block/sda/device/unload_heads", seconds*1000);
  44 }
  45
  46 int on_ac(void)
  47 {
  48 //      /sys/class/power_supply/AC0/online
  49 }
  50
  51 int lid_open(void)
  52 {
  53 //      /proc/acpi/button/lid/LID/state
  54 }
  55
  56 void ignore_me(void)
  57 {
  58         protect(0);
  59         set_led(0);
  60
  61 }
  62
  63 int main(int argc, char* argv[])
  64 {
  65        int fd, ret;
  66
  67        fd = open("/dev/freefall", O_RDONLY);
  68        if (fd < 0) {
  69                perror("open");
  70                return EXIT_FAILURE;
  71        }
  72
  73         signal(SIGALRM, ignore_me);
  74
  75        for (;;) {
  76                unsigned char count;
  77
  78                ret = read(fd, &count, sizeof(count));
  79                alarm(0);
  80                if ((ret == -1) && (errno == EINTR)) {
  81                        /* Alarm expired, time to unpark the heads */
  82                        continue;
  83                }
  84
  85                if (ret != sizeof(count)) {
  86                        perror("read");
  87                        break;
  88                }
  89
  90                protect(21);
  91                set_led(1);
  92                if (1 || on_ac() || lid_open()) {
  93                        alarm(2);
  94                } else {
  95                        alarm(20);
  96                }
  97        }
  98
  99        close(fd);
 100        return EXIT_SUCCESS;
 101 }