xref: /openbmc/linux/tools/laptop/freefall/freefall.c (revision 4f6cce39)
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 	if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
33 		return -EINVAL;
34 	strncpy(device_path, device, sizeof(device_path) - 1);
35 
36 	snprintf(unload_heads_path, sizeof(unload_heads_path) - 1,
37 				"/sys/block/%s/device/unload_heads", device+5);
38 	return 0;
39 }
40 
41 static int valid_disk(void)
42 {
43 	int fd = open(unload_heads_path, O_RDONLY);
44 
45 	if (fd < 0) {
46 		perror(unload_heads_path);
47 		return 0;
48 	}
49 
50 	close(fd);
51 	return 1;
52 }
53 
54 static void write_int(char *path, int i)
55 {
56 	char buf[1024];
57 	int fd = open(path, O_RDWR);
58 
59 	if (fd < 0) {
60 		perror("open");
61 		exit(1);
62 	}
63 
64 	sprintf(buf, "%d", i);
65 
66 	if (write(fd, buf, strlen(buf)) != strlen(buf)) {
67 		perror("write");
68 		exit(1);
69 	}
70 
71 	close(fd);
72 }
73 
74 static void set_led(int on)
75 {
76 	if (noled)
77 		return;
78 	write_int("/sys/class/leds/hp::hddprotect/brightness", on);
79 }
80 
81 static void protect(int seconds)
82 {
83 	const char *str = (seconds == 0) ? "Unparked" : "Parked";
84 
85 	write_int(unload_heads_path, seconds*1000);
86 	syslog(LOG_INFO, "%s %s disk head\n", str, device_path);
87 }
88 
89 static int on_ac(void)
90 {
91 	/* /sys/class/power_supply/AC0/online */
92 	return 1;
93 }
94 
95 static int lid_open(void)
96 {
97 	/* /proc/acpi/button/lid/LID/state */
98 	return 1;
99 }
100 
101 static void ignore_me(int signum)
102 {
103 	protect(0);
104 	set_led(0);
105 }
106 
107 int main(int argc, char **argv)
108 {
109 	int fd, ret;
110 	struct stat st;
111 	struct sched_param param;
112 
113 	if (argc == 1)
114 		ret = set_unload_heads_path("/dev/sda");
115 	else if (argc == 2)
116 		ret = set_unload_heads_path(argv[1]);
117 	else
118 		ret = -EINVAL;
119 
120 	if (ret || !valid_disk()) {
121 		fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
122 				argv[0]);
123 		exit(1);
124 	}
125 
126 	fd = open("/dev/freefall", O_RDONLY);
127 	if (fd < 0) {
128 		perror("/dev/freefall");
129 		return EXIT_FAILURE;
130 	}
131 
132 	if (stat("/sys/class/leds/hp::hddprotect/brightness", &st))
133 		noled = 1;
134 
135 	if (daemon(0, 0) != 0) {
136 		perror("daemon");
137 		return EXIT_FAILURE;
138 	}
139 
140 	openlog(app_name, LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
141 
142 	param.sched_priority = sched_get_priority_max(SCHED_FIFO);
143 	sched_setscheduler(0, SCHED_FIFO, &param);
144 	mlockall(MCL_CURRENT|MCL_FUTURE);
145 
146 	signal(SIGALRM, ignore_me);
147 
148 	for (;;) {
149 		unsigned char count;
150 
151 		ret = read(fd, &count, sizeof(count));
152 		alarm(0);
153 		if ((ret == -1) && (errno == EINTR)) {
154 			/* Alarm expired, time to unpark the heads */
155 			continue;
156 		}
157 
158 		if (ret != sizeof(count)) {
159 			perror("read");
160 			break;
161 		}
162 
163 		protect(21);
164 		set_led(1);
165 		if (1 || on_ac() || lid_open())
166 			alarm(2);
167 		else
168 			alarm(20);
169 	}
170 
171 	closelog();
172 	close(fd);
173 	return EXIT_SUCCESS;
174 }
175