2bace8b951
Improve the example code to be at least useable, as in not causing harm (as shown below). Code can still be improved further, but this adds some basic safeguards. 1. hpfall *MUST* mlockall(MCL_CURRENT|MCL_FUTURE); itself! Since the Program sits and waits most of the time it becomes very likely swapped out. If it gets woken up when the laptop drops from the table while it is swapped out it actually triggers harddrive activity! 2. Daemonize hpfall using 'daemon(0,0)' (quick and dirty). 3. Give hpfall realtime priority. Should give a chance that it has less latency when woken up. Signed-off-by: Christian Thaeter <ct@pipapo.org> Signed-off-by: Frans Pop <elendil@planet.nl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
108 lines
1.7 KiB
C
108 lines
1.7 KiB
C
/* Disk protection for HP machines.
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*
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* Copyright 2008 Eric Piel
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* Copyright 2009 Pavel Machek <pavel@suse.cz>
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*
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* GPLv2.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <string.h>
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#include <stdint.h>
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#include <errno.h>
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#include <signal.h>
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#include <sys/mman.h>
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#include <sched.h>
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void write_int(char *path, int i)
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{
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char buf[1024];
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int fd = open(path, O_RDWR);
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if (fd < 0) {
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perror("open");
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exit(1);
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}
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sprintf(buf, "%d", i);
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if (write(fd, buf, strlen(buf)) != strlen(buf)) {
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perror("write");
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exit(1);
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}
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close(fd);
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}
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void set_led(int on)
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{
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write_int("/sys/class/leds/hp::hddprotect/brightness", on);
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}
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void protect(int seconds)
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{
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write_int("/sys/block/sda/device/unload_heads", seconds*1000);
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}
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int on_ac(void)
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{
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// /sys/class/power_supply/AC0/online
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}
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int lid_open(void)
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{
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// /proc/acpi/button/lid/LID/state
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}
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void ignore_me(void)
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{
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protect(0);
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set_led(0);
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}
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int main(int argc, char *argv[])
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{
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int fd, ret;
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struct sched_param param;
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fd = open("/dev/freefall", O_RDONLY);
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if (fd < 0) {
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perror("open");
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return EXIT_FAILURE;
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}
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daemon(0, 0);
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param.sched_priority = sched_get_priority_max(SCHED_FIFO);
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sched_setscheduler(0, SCHED_FIFO, ¶m);
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mlockall(MCL_CURRENT|MCL_FUTURE);
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signal(SIGALRM, ignore_me);
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for (;;) {
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unsigned char count;
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ret = read(fd, &count, sizeof(count));
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alarm(0);
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if ((ret == -1) && (errno == EINTR)) {
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/* Alarm expired, time to unpark the heads */
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continue;
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}
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if (ret != sizeof(count)) {
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perror("read");
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break;
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}
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protect(21);
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set_led(1);
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if (1 || on_ac() || lid_open())
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alarm(2);
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else
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alarm(20);
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}
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close(fd);
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return EXIT_SUCCESS;
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}
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