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 
set_unload_heads_path(char * device)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 
valid_disk(void)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 
write_int(char * path,int i)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 
set_led(int on)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 
protect(int seconds)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 
on_ac(void)88 static int on_ac(void)
89 {
90 	/* /sys/class/power_supply/AC0/online */
91 	return 1;
92 }
93 
lid_open(void)94 static int lid_open(void)
95 {
96 	/* /proc/acpi/button/lid/LID/state */
97 	return 1;
98 }
99 
ignore_me(int signum)100 static void ignore_me(int signum)
101 {
102 	protect(0);
103 	set_led(0);
104 }
105 
main(int argc,char ** argv)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 }
174