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 #include <sys/mman.h>
  20 #include <sched.h>
  21
  22 char unload_heads_path[64];
  23
  24 int set_unload_heads_path(char *device)
  25 {
  26         char devname[64];
  27
  28         if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
  29                 return -EINVAL;
  30         strncpy(devname, device + 5, sizeof(devname));
  31
  32         snprintf(unload_heads_path, sizeof(unload_heads_path),
  33                                 "/sys/block/%s/device/unload_heads", devname);
  34         return 0;
  35 }
  36 int valid_disk(void)
  37 {
  38         int fd = open(unload_heads_path, O_RDONLY);
  39         if (fd < 0) {
  40                 perror(unload_heads_path);
  41                 return 0;
  42         }
  43
  44         close(fd);
  45         return 1;
  46 }
  47
  48 void write_int(char *path, int i)
  49 {
  50         char buf[1024];
  51         int fd = open(path, O_RDWR);
  52         if (fd < 0) {
  53                 perror("open");
  54                 exit(1);
  55         }
  56         sprintf(buf, "%d", i);
  57         if (write(fd, buf, strlen(buf)) != strlen(buf)) {
  58                 perror("write");
  59                 exit(1);
  60         }
  61         close(fd);
  62 }
  63
  64 void set_led(int on)
  65 {
  66         write_int("/sys/class/leds/hp::hddprotect/brightness", on);
  67 }
  68
  69 void protect(int seconds)
  70 {
  71         write_int(unload_heads_path, seconds*1000);
  72 }
  73
  74 int on_ac(void)
  75 {
  76 //      /sys/class/power_supply/AC0/online
  77 }
  78
  79 int lid_open(void)
  80 {
  81 //      /proc/acpi/button/lid/LID/state
  82 }
  83
  84 void ignore_me(void)
  85 {
  86         protect(0);
  87         set_led(0);
  88 }
  89
  90 int main(int argc, char **argv)
  91 {
  92         int fd, ret;
  93         struct sched_param param;
  94
  95         if (argc == 1)
  96                 ret = set_unload_heads_path("/dev/sda");
  97         else if (argc == 2)
  98                 ret = set_unload_heads_path(argv[1]);
  99         else
 100                 ret = -EINVAL;
 101
 102         if (ret || !valid_disk()) {
 103                 fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
 104                                 argv[0]);
 105                 exit(1);
 106         }
 107
 108         fd = open("/dev/freefall", O_RDONLY);
 109         if (fd < 0) {
 110                 perror("/dev/freefall");
 111                 return EXIT_FAILURE;
 112         }
 113
 114         daemon(0, 0);
 115         param.sched_priority = sched_get_priority_max(SCHED_FIFO);
 116         sched_setscheduler(0, SCHED_FIFO, &param);
 117         mlockall(MCL_CURRENT|MCL_FUTURE);
 118
 119         signal(SIGALRM, ignore_me);
 120
 121         for (;;) {
 122                 unsigned char count;
 123
 124                 ret = read(fd, &count, sizeof(count));
 125                 alarm(0);
 126                 if ((ret == -1) && (errno == EINTR)) {
 127                         /* Alarm expired, time to unpark the heads */
 128                         continue;
 129                 }
 130
 131                 if (ret != sizeof(count)) {
 132                         perror("read");
 133                         break;
 134                 }
 135
 136                 protect(21);
 137                 set_led(1);
 138                 if (1 || on_ac() || lid_open())
 139                         alarm(2);
 140                 else
 141                         alarm(20);
 142         }
 143
 144         close(fd);
 145         return EXIT_SUCCESS;
 146 }