tools/laptop/freefall/freefall.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Disk protection for HP/DELL machines.
   3  *
   4  * Copyright 2008 Eric Piel
   5  * Copyright 2009 Pavel Machek <pavel@ucw.cz>
   6  * Copyright 2012 Sonal Santan
   7  * Copyright 2014 Pali Rohár <pali@kernel.org>
   8  */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <fcntl.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include <string.h>
  17 #include <stdint.h>
  18 #include <errno.h>
  19 #include <signal.h>
  20 #include <sys/mman.h>
  21 #include <sched.h>
  22 #include <syslog.h>
  23
  24 static int noled;
  25 static char unload_heads_path[64];
  26 static char device_path[32];
  27 static const char app_name[] = "FREE FALL";
  28
  29 static int set_unload_heads_path(char *device)
  30 {
  31         if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
  32                 return -EINVAL;
  33         strncpy(device_path, device, sizeof(device_path) - 1);
  34
  35         snprintf(unload_heads_path, sizeof(unload_heads_path) - 1,
  36                                 "/sys/block/%s/device/unload_heads", device+5);
  37         return 0;
  38 }
  39
  40 static int valid_disk(void)
  41 {
  42         int fd = open(unload_heads_path, O_RDONLY);
  43
  44         if (fd < 0) {
  45                 perror(unload_heads_path);
  46                 return 0;
  47         }
  48
  49         close(fd);
  50         return 1;
  51 }
  52
  53 static void write_int(char *path, int i)
  54 {
  55         char buf[1024];
  56         int fd = open(path, O_RDWR);
  57
  58         if (fd < 0) {
  59                 perror("open");
  60                 exit(1);
  61         }
  62
  63         sprintf(buf, "%d", i);
  64
  65         if (write(fd, buf, strlen(buf)) != strlen(buf)) {
  66                 perror("write");
  67                 exit(1);
  68         }
  69
  70         close(fd);
  71 }
  72
  73 static void set_led(int on)
  74 {
  75         if (noled)
  76                 return;
  77         write_int("/sys/class/leds/hp::hddprotect/brightness", on);
  78 }
  79
  80 static void protect(int seconds)
  81 {
  82         const char *str = (seconds == 0) ? "Unparked" : "Parked";
  83
  84         write_int(unload_heads_path, seconds*1000);
  85         syslog(LOG_INFO, "%s %s disk head\n", str, device_path);
  86 }
  87
  88 static int on_ac(void)
  89 {
  90         /* /sys/class/power_supply/AC0/online */
  91         return 1;
  92 }
  93
  94 static int lid_open(void)
  95 {
  96         /* /proc/acpi/button/lid/LID/state */
  97         return 1;
  98 }
  99
 100 static void ignore_me(int signum)
 101 {
 102         protect(0);
 103         set_led(0);
 104 }
 105
 106 int main(int argc, char **argv)
 107 {
 108         int fd, ret;
 109         struct stat st;
 110         struct sched_param param;
 111
 112         if (argc == 1)
 113                 ret = set_unload_heads_path("/dev/sda");
 114         else if (argc == 2)
 115                 ret = set_unload_heads_path(argv[1]);
 116         else
 117                 ret = -EINVAL;
 118
 119         if (ret || !valid_disk()) {
 120                 fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
 121                                 argv[0]);
 122                 exit(1);
 123         }
 124
 125         fd = open("/dev/freefall", O_RDONLY);
 126         if (fd < 0) {
 127                 perror("/dev/freefall");
 128                 return EXIT_FAILURE;
 129         }
 130
 131         if (stat("/sys/class/leds/hp::hddprotect/brightness", &st))
 132                 noled = 1;
 133
 134         if (daemon(0, 0) != 0) {
 135                 perror("daemon");
 136                 return EXIT_FAILURE;
 137         }
 138
 139         openlog(app_name, LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
 140
 141         param.sched_priority = sched_get_priority_max(SCHED_FIFO);
 142         sched_setscheduler(0, SCHED_FIFO, &param);
 143         mlockall(MCL_CURRENT|MCL_FUTURE);
 144
 145         signal(SIGALRM, ignore_me);
 146
 147         for (;;) {
 148                 unsigned char count;
 149
 150                 ret = read(fd, &count, sizeof(count));
 151                 alarm(0);
 152                 if ((ret == -1) && (errno == EINTR)) {
 153                         /* Alarm expired, time to unpark the heads */
 154                         continue;
 155                 }
 156
 157                 if (ret != sizeof(count)) {
 158                         perror("read");
 159                         break;
 160                 }
 161
 162                 protect(21);
 163                 set_led(1);
 164                 if (1 || on_ac() || lid_open())
 165                         alarm(2);
 166                 else
 167                         alarm(20);
 168         }
 169
 170         closelog();
 171         close(fd);
 172         return EXIT_SUCCESS;
 173 }