About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / laptops / freefall.c




Custom Search

Based on kernel version 3.16. Page generated on 2014-08-06 21:40 EST.

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	
25	static int noled;
26	static char unload_heads_path[64];
27	static char device_path[32];
28	static const char app_name[] = "FREE FALL";
29	
30	static int set_unload_heads_path(char *device)
31	{
32		char devname[64];
33	
34		if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
35			return -EINVAL;
36		strncpy(devname, device + 5, sizeof(devname) - 1);
37		strncpy(device_path, device, sizeof(device_path) - 1);
38	
39		snprintf(unload_heads_path, sizeof(unload_heads_path) - 1,
40					"/sys/block/%s/device/unload_heads", devname);
41		return 0;
42	}
43	
44	static int valid_disk(void)
45	{
46		int fd = open(unload_heads_path, O_RDONLY);
47	
48		if (fd < 0) {
49			perror(unload_heads_path);
50			return 0;
51		}
52	
53		close(fd);
54		return 1;
55	}
56	
57	static void write_int(char *path, int i)
58	{
59		char buf[1024];
60		int fd = open(path, O_RDWR);
61	
62		if (fd < 0) {
63			perror("open");
64			exit(1);
65		}
66	
67		sprintf(buf, "%d", i);
68	
69		if (write(fd, buf, strlen(buf)) != strlen(buf)) {
70			perror("write");
71			exit(1);
72		}
73	
74		close(fd);
75	}
76	
77	static void set_led(int on)
78	{
79		if (noled)
80			return;
81		write_int("/sys/class/leds/hp::hddprotect/brightness", on);
82	}
83	
84	static void protect(int seconds)
85	{
86		const char *str = (seconds == 0) ? "Unparked" : "Parked";
87	
88		write_int(unload_heads_path, seconds*1000);
89		syslog(LOG_INFO, "%s %s disk head\n", str, device_path);
90	}
91	
92	static int on_ac(void)
93	{
94		/* /sys/class/power_supply/AC0/online */
95		return 1;
96	}
97	
98	static int lid_open(void)
99	{
100		/* /proc/acpi/button/lid/LID/state */
101		return 1;
102	}
103	
104	static void ignore_me(int signum)
105	{
106		protect(0);
107		set_led(0);
108	}
109	
110	int main(int argc, char **argv)
111	{
112		int fd, ret;
113		struct stat st;
114		struct sched_param param;
115	
116		if (argc == 1)
117			ret = set_unload_heads_path("/dev/sda");
118		else if (argc == 2)
119			ret = set_unload_heads_path(argv[1]);
120		else
121			ret = -EINVAL;
122	
123		if (ret || !valid_disk()) {
124			fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
125					argv[0]);
126			exit(1);
127		}
128	
129		fd = open("/dev/freefall", O_RDONLY);
130		if (fd < 0) {
131			perror("/dev/freefall");
132			return EXIT_FAILURE;
133		}
134	
135		if (stat("/sys/class/leds/hp::hddprotect/brightness", &st))
136			noled = 1;
137	
138		if (daemon(0, 0) != 0) {
139			perror("daemon");
140			return EXIT_FAILURE;
141		}
142	
143		openlog(app_name, LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
144	
145		param.sched_priority = sched_get_priority_max(SCHED_FIFO);
146		sched_setscheduler(0, SCHED_FIFO, &param);
147		mlockall(MCL_CURRENT|MCL_FUTURE);
148	
149		signal(SIGALRM, ignore_me);
150	
151		for (;;) {
152			unsigned char count;
153	
154			ret = read(fd, &count, sizeof(count));
155			alarm(0);
156			if ((ret == -1) && (errno == EINTR)) {
157				/* Alarm expired, time to unpark the heads */
158				continue;
159			}
160	
161			if (ret != sizeof(count)) {
162				perror("read");
163				break;
164			}
165	
166			protect(21);
167			set_led(1);
168			if (1 || on_ac() || lid_open())
169				alarm(2);
170			else
171				alarm(20);
172		}
173	
174		closelog();
175		close(fd);
176		return EXIT_SUCCESS;
177	}
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.