summaryrefslogtreecommitdiffstats
path: root/Documentation/laptops/freefall.c
blob: aab2ff09e86842aec48ba0d61b7972f4cae1f4c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/* Disk protection for HP/DELL machines.
 *
 * Copyright 2008 Eric Piel
 * Copyright 2009 Pavel Machek <pavel@ucw.cz>
 * Copyright 2012 Sonal Santan
 * Copyright 2014 Pali Rohár <pali.rohar@gmail.com>
 *
 * 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>
#include <syslog.h>

static int noled;
static char unload_heads_path[64];
static char device_path[32];
static const char app_name[] = "FREE FALL";

static 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) - 1);
	strncpy(device_path, device, sizeof(device_path) - 1);

	snprintf(unload_heads_path, sizeof(unload_heads_path) - 1,
				"/sys/block/%s/device/unload_heads", devname);
	return 0;
}

static 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;
}

static 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);
}

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

static void protect(int seconds)
{
	const char *str = (seconds == 0) ? "Unparked" : "Parked";

	write_int(unload_heads_path, seconds*1000);
	syslog(LOG_INFO, "%s %s disk head\n", str, device_path);
}

static int on_ac(void)
{
	/* /sys/class/power_supply/AC0/online */
	return 1;
}

static int lid_open(void)
{
	/* /proc/acpi/button/lid/LID/state */
	return 1;
}

static void ignore_me(int signum)
{
	protect(0);
	set_led(0);
}

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

	if (stat("/sys/class/leds/hp::hddprotect/brightness", &st))
		noled = 1;

	if (daemon(0, 0) != 0) {
		perror("daemon");
		return EXIT_FAILURE;
	}

	openlog(app_name, LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);

	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);
	}

	closelog();
	close(fd);
	return EXIT_SUCCESS;
}