hpfall.c

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/* Disk protection for HP machines.
 *
 * Copyright 2008 Eric Piel
 * Copyright 2009 Pavel Machek <[email protected]>
 *
 * 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>

char unload_heads_path[64];

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));

    snprintf(unload_heads_path, sizeof(unload_heads_path),
                "/sys/block/%s/device/unload_heads", devname);
    return 0;
}
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;
}

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);
}

void set_led(int on)
{
    write_int("/sys/class/leds/hp::hddprotect/brightness", on);
}

void protect(int seconds)
{
    write_int(unload_heads_path, seconds*1000);
}

int on_ac(void)
{
//  /sys/class/power_supply/AC0/online
}

int lid_open(void)
{
//  /proc/acpi/button/lid/LID/state
}

void ignore_me(void)
{
    protect(0);
    set_led(0);
}

int main(int argc, char **argv)
{
    int fd, ret;
    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;
    }

    daemon(0, 0);
    param.sched_priority = sched_get_priority_max(SCHED_FIFO);
    sched_setscheduler(0, SCHED_FIFO, &param);
    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);
    }

    close(fd);
    return EXIT_SUCCESS;
}