LXR linux/Documentation/laptops/hpfall.c

   1/* Disk protection for HP machines.
   2 *
   3 * Copyright 2008 Eric Piel
   4 * Copyright 2009 Pavel Machek <pavel@ucw.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
  22char unload_heads_path[64];
  23
  24int 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}
  36int 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
  48void 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
  64void set_led(int on)
  65{
  66        write_int("/sys/class/leds/hp::hddprotect/brightness", on);
  67}
  68
  69void protect(int seconds)
  70{
  71        write_int(unload_heads_path, seconds*1000);
  72}
  73
  74int on_ac(void)
  75{
  76//      /sys/class/power_supply/AC0/online
  77}
  78
  79int lid_open(void)
  80{
  81//      /proc/acpi/button/lid/LID/state
  82}
  83
  84void ignore_me(void)
  85{
  86        protect(0);
  87        set_led(0);
  88}
  89
  90int 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}
 147