LXR linux/tools/laptop/freefall/freefall.c

   1/* Disk protection for HP/DELL machines.
   2 *
   3 * Copyright 2008 Eric Piel
   4 * Copyright 2009 Pavel Machek <pavel@ucw.cz>
   5 * Copyright 2012 Sonal Santan
   6 * Copyright 2014 Pali Rohár <pali.rohar@gmail.com>
   7 *
   8 * GPLv2.
   9 */
  10
  11#include <stdio.h>
  12#include <stdlib.h>
  13#include <unistd.h>
  14#include <fcntl.h>
  15#include <sys/stat.h>
  16#include <sys/types.h>
  17#include <string.h>
  18#include <stdint.h>
  19#include <errno.h>
  20#include <signal.h>
  21#include <sys/mman.h>
  22#include <sched.h>
  23#include <syslog.h>
  24
  25static int noled;
  26static char unload_heads_path[64];
  27static char device_path[32];
  28static const char app_name[] = "FREE FALL";
  29
  30static int set_unload_heads_path(char *device)
  31{
  32        if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
  33                return -EINVAL;
  34        strncpy(device_path, device, sizeof(device_path) - 1);
  35
  36        snprintf(unload_heads_path, sizeof(unload_heads_path) - 1,
  37                                "/sys/block/%s/device/unload_heads", device+5);
  38        return 0;
  39}
  40
  41static int valid_disk(void)
  42{
  43        int fd = open(unload_heads_path, O_RDONLY);
  44
  45        if (fd < 0) {
  46                perror(unload_heads_path);
  47                return 0;
  48        }
  49
  50        close(fd);
  51        return 1;
  52}
  53
  54static void write_int(char *path, int i)
  55{
  56        char buf[1024];
  57        int fd = open(path, O_RDWR);
  58
  59        if (fd < 0) {
  60                perror("open");
  61                exit(1);
  62        }
  63
  64        sprintf(buf, "%d", i);
  65
  66        if (write(fd, buf, strlen(buf)) != strlen(buf)) {
  67                perror("write");
  68                exit(1);
  69        }
  70
  71        close(fd);
  72}
  73
  74static void set_led(int on)
  75{
  76        if (noled)
  77                return;
  78        write_int("/sys/class/leds/hp::hddprotect/brightness", on);
  79}
  80
  81static void protect(int seconds)
  82{
  83        const char *str = (seconds == 0) ? "Unparked" : "Parked";
  84
  85        write_int(unload_heads_path, seconds*1000);
  86        syslog(LOG_INFO, "%s %s disk head\n", str, device_path);
  87}
  88
  89static int on_ac(void)
  90{
  91        /* /sys/class/power_supply/AC0/online */
  92        return 1;
  93}
  94
  95static int lid_open(void)
  96{
  97        /* /proc/acpi/button/lid/LID/state */
  98        return 1;
  99}
 100
 101static void ignore_me(int signum)
 102{
 103        protect(0);
 104        set_led(0);
 105}
 106
 107int main(int argc, char **argv)
 108{
 109        int fd, ret;
 110        struct stat st;
 111        struct sched_param param;
 112
 113        if (argc == 1)
 114                ret = set_unload_heads_path("/dev/sda");
 115        else if (argc == 2)
 116                ret = set_unload_heads_path(argv[1]);
 117        else
 118                ret = -EINVAL;
 119
 120        if (ret || !valid_disk()) {
 121                fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
 122                                argv[0]);
 123                exit(1);
 124        }
 125
 126        fd = open("/dev/freefall", O_RDONLY);
 127        if (fd < 0) {
 128                perror("/dev/freefall");
 129                return EXIT_FAILURE;
 130        }
 131
 132        if (stat("/sys/class/leds/hp::hddprotect/brightness", &st))
 133                noled = 1;
 134
 135        if (daemon(0, 0) != 0) {
 136                perror("daemon");
 137                return EXIT_FAILURE;
 138        }
 139
 140        openlog(app_name, LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
 141
 142        param.sched_priority = sched_get_priority_max(SCHED_FIFO);
 143        sched_setscheduler(0, SCHED_FIFO, &param);
 144        mlockall(MCL_CURRENT|MCL_FUTURE);
 145
 146        signal(SIGALRM, ignore_me);
 147
 148        for (;;) {
 149                unsigned char count;
 150
 151                ret = read(fd, &count, sizeof(count));
 152                alarm(0);
 153                if ((ret == -1) && (errno == EINTR)) {
 154                        /* Alarm expired, time to unpark the heads */
 155                        continue;
 156                }
 157
 158                if (ret != sizeof(count)) {
 159                        perror("read");
 160                        break;
 161                }
 162
 163                protect(21);
 164                set_led(1);
 165                if (1 || on_ac() || lid_open())
 166                        alarm(2);
 167                else
 168                        alarm(20);
 169        }
 170
 171        closelog();
 172        close(fd);
 173        return EXIT_SUCCESS;
 174}
 175