xref: /linux/kernel/power/user.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5) 
1 /*
2  * linux/kernel/power/user.c
3  *
4  * This file provides the user space interface for software suspend/resume.
5  *
6  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
7  *
8  * This file is released under the GPLv2.
9  *
10  */
11 
12 #include <linux/suspend.h>
13 #include <linux/syscalls.h>
14 #include <linux/reboot.h>
15 #include <linux/string.h>
16 #include <linux/device.h>
17 #include <linux/miscdevice.h>
18 #include <linux/mm.h>
19 #include <linux/swap.h>
20 #include <linux/swapops.h>
21 #include <linux/pm.h>
22 #include <linux/fs.h>
23 #include <linux/console.h>
24 #include <linux/cpu.h>
25 #include <linux/freezer.h>
26 #include <scsi/scsi_scan.h>
27 
28 #include <asm/uaccess.h>
29 
30 #include "power.h"
31 
32 /*
33  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
34  * will be removed in the future.  They are only preserved here for
35  * compatibility with existing userland utilities.
36  */
37 #define SNAPSHOT_SET_SWAP_FILE	_IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
38 #define SNAPSHOT_PMOPS		_IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
39 
40 #define PMOPS_PREPARE	1
41 #define PMOPS_ENTER	2
42 #define PMOPS_FINISH	3
43 
44 /*
45  * NOTE: The following ioctl definitions are wrong and have been replaced with
46  * correct ones.  They are only preserved here for compatibility with existing
47  * userland utilities and will be removed in the future.
48  */
49 #define SNAPSHOT_ATOMIC_SNAPSHOT	_IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
50 #define SNAPSHOT_SET_IMAGE_SIZE		_IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
51 #define SNAPSHOT_AVAIL_SWAP		_IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
52 #define SNAPSHOT_GET_SWAP_PAGE		_IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
53 
54 
55 #define SNAPSHOT_MINOR	231
56 
57 static struct snapshot_data {
58 	struct snapshot_handle handle;
59 	int swap;
60 	int mode;
61 	char frozen;
62 	char ready;
63 	char platform_support;
64 } snapshot_state;
65 
66 atomic_t snapshot_device_available = ATOMIC_INIT(1);
67 
68 static int snapshot_open(struct inode *inode, struct file *filp)
69 {
70 	struct snapshot_data *data;
71 	int error;
72 
73 	mutex_lock(&pm_mutex);
74 
75 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
76 		error = -EBUSY;
77 		goto Unlock;
78 	}
79 
80 	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
81 		atomic_inc(&snapshot_device_available);
82 		error = -ENOSYS;
83 		goto Unlock;
84 	}
85 	if(create_basic_memory_bitmaps()) {
86 		atomic_inc(&snapshot_device_available);
87 		error = -ENOMEM;
88 		goto Unlock;
89 	}
90 	nonseekable_open(inode, filp);
91 	data = &snapshot_state;
92 	filp->private_data = data;
93 	memset(&data->handle, 0, sizeof(struct snapshot_handle));
94 	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
95 		/* Hibernating.  The image device should be accessible. */
96 		data->swap = swsusp_resume_device ?
97 			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
98 		data->mode = O_RDONLY;
99 		error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
100 		if (error)
101 			pm_notifier_call_chain(PM_POST_HIBERNATION);
102 	} else {
103 		/*
104 		 * Resuming.  We may need to wait for the image device to
105 		 * appear.
106 		 */
107 		wait_for_device_probe();
108 		scsi_complete_async_scans();
109 
110 		data->swap = -1;
111 		data->mode = O_WRONLY;
112 		error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
113 		if (error)
114 			pm_notifier_call_chain(PM_POST_RESTORE);
115 	}
116 	if (error)
117 		atomic_inc(&snapshot_device_available);
118 	data->frozen = 0;
119 	data->ready = 0;
120 	data->platform_support = 0;
121 
122  Unlock:
123 	mutex_unlock(&pm_mutex);
124 
125 	return error;
126 }
127 
128 static int snapshot_release(struct inode *inode, struct file *filp)
129 {
130 	struct snapshot_data *data;
131 
132 	mutex_lock(&pm_mutex);
133 
134 	swsusp_free();
135 	free_basic_memory_bitmaps();
136 	data = filp->private_data;
137 	free_all_swap_pages(data->swap);
138 	if (data->frozen)
139 		thaw_processes();
140 	pm_notifier_call_chain(data->mode == O_WRONLY ?
141 			PM_POST_HIBERNATION : PM_POST_RESTORE);
142 	atomic_inc(&snapshot_device_available);
143 
144 	mutex_unlock(&pm_mutex);
145 
146 	return 0;
147 }
148 
149 static ssize_t snapshot_read(struct file *filp, char __user *buf,
150                              size_t count, loff_t *offp)
151 {
152 	struct snapshot_data *data;
153 	ssize_t res;
154 
155 	mutex_lock(&pm_mutex);
156 
157 	data = filp->private_data;
158 	if (!data->ready) {
159 		res = -ENODATA;
160 		goto Unlock;
161 	}
162 	res = snapshot_read_next(&data->handle, count);
163 	if (res > 0) {
164 		if (copy_to_user(buf, data_of(data->handle), res))
165 			res = -EFAULT;
166 		else
167 			*offp = data->handle.offset;
168 	}
169 
170  Unlock:
171 	mutex_unlock(&pm_mutex);
172 
173 	return res;
174 }
175 
176 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
177                               size_t count, loff_t *offp)
178 {
179 	struct snapshot_data *data;
180 	ssize_t res;
181 
182 	mutex_lock(&pm_mutex);
183 
184 	data = filp->private_data;
185 	res = snapshot_write_next(&data->handle, count);
186 	if (res > 0) {
187 		if (copy_from_user(data_of(data->handle), buf, res))
188 			res = -EFAULT;
189 		else
190 			*offp = data->handle.offset;
191 	}
192 
193 	mutex_unlock(&pm_mutex);
194 
195 	return res;
196 }
197 
198 static void snapshot_deprecated_ioctl(unsigned int cmd)
199 {
200 	if (printk_ratelimit())
201 		printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
202 				"be removed soon, update your suspend-to-disk "
203 				"utilities\n",
204 				__builtin_return_address(0), cmd);
205 }
206 
207 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
208 							unsigned long arg)
209 {
210 	int error = 0;
211 	struct snapshot_data *data;
212 	loff_t size;
213 	sector_t offset;
214 
215 	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
216 		return -ENOTTY;
217 	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
218 		return -ENOTTY;
219 	if (!capable(CAP_SYS_ADMIN))
220 		return -EPERM;
221 
222 	if (!mutex_trylock(&pm_mutex))
223 		return -EBUSY;
224 
225 	data = filp->private_data;
226 
227 	switch (cmd) {
228 
229 	case SNAPSHOT_FREEZE:
230 		if (data->frozen)
231 			break;
232 
233 		printk("Syncing filesystems ... ");
234 		sys_sync();
235 		printk("done.\n");
236 
237 		error = usermodehelper_disable();
238 		if (error)
239 			break;
240 
241 		error = freeze_processes();
242 		if (error) {
243 			thaw_processes();
244 			usermodehelper_enable();
245 		}
246 		if (!error)
247 			data->frozen = 1;
248 		break;
249 
250 	case SNAPSHOT_UNFREEZE:
251 		if (!data->frozen || data->ready)
252 			break;
253 		thaw_processes();
254 		usermodehelper_enable();
255 		data->frozen = 0;
256 		break;
257 
258 	case SNAPSHOT_ATOMIC_SNAPSHOT:
259 		snapshot_deprecated_ioctl(cmd);
260 	case SNAPSHOT_CREATE_IMAGE:
261 		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
262 			error = -EPERM;
263 			break;
264 		}
265 		error = hibernation_snapshot(data->platform_support);
266 		if (!error)
267 			error = put_user(in_suspend, (int __user *)arg);
268 		if (!error)
269 			data->ready = 1;
270 		break;
271 
272 	case SNAPSHOT_ATOMIC_RESTORE:
273 		snapshot_write_finalize(&data->handle);
274 		if (data->mode != O_WRONLY || !data->frozen ||
275 		    !snapshot_image_loaded(&data->handle)) {
276 			error = -EPERM;
277 			break;
278 		}
279 		error = hibernation_restore(data->platform_support);
280 		break;
281 
282 	case SNAPSHOT_FREE:
283 		swsusp_free();
284 		memset(&data->handle, 0, sizeof(struct snapshot_handle));
285 		data->ready = 0;
286 		break;
287 
288 	case SNAPSHOT_SET_IMAGE_SIZE:
289 		snapshot_deprecated_ioctl(cmd);
290 	case SNAPSHOT_PREF_IMAGE_SIZE:
291 		image_size = arg;
292 		break;
293 
294 	case SNAPSHOT_GET_IMAGE_SIZE:
295 		if (!data->ready) {
296 			error = -ENODATA;
297 			break;
298 		}
299 		size = snapshot_get_image_size();
300 		size <<= PAGE_SHIFT;
301 		error = put_user(size, (loff_t __user *)arg);
302 		break;
303 
304 	case SNAPSHOT_AVAIL_SWAP:
305 		snapshot_deprecated_ioctl(cmd);
306 	case SNAPSHOT_AVAIL_SWAP_SIZE:
307 		size = count_swap_pages(data->swap, 1);
308 		size <<= PAGE_SHIFT;
309 		error = put_user(size, (loff_t __user *)arg);
310 		break;
311 
312 	case SNAPSHOT_GET_SWAP_PAGE:
313 		snapshot_deprecated_ioctl(cmd);
314 	case SNAPSHOT_ALLOC_SWAP_PAGE:
315 		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
316 			error = -ENODEV;
317 			break;
318 		}
319 		offset = alloc_swapdev_block(data->swap);
320 		if (offset) {
321 			offset <<= PAGE_SHIFT;
322 			error = put_user(offset, (loff_t __user *)arg);
323 		} else {
324 			error = -ENOSPC;
325 		}
326 		break;
327 
328 	case SNAPSHOT_FREE_SWAP_PAGES:
329 		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
330 			error = -ENODEV;
331 			break;
332 		}
333 		free_all_swap_pages(data->swap);
334 		break;
335 
336 	case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
337 		snapshot_deprecated_ioctl(cmd);
338 		if (!swsusp_swap_in_use()) {
339 			/*
340 			 * User space encodes device types as two-byte values,
341 			 * so we need to recode them
342 			 */
343 			if (old_decode_dev(arg)) {
344 				data->swap = swap_type_of(old_decode_dev(arg),
345 							0, NULL);
346 				if (data->swap < 0)
347 					error = -ENODEV;
348 			} else {
349 				data->swap = -1;
350 				error = -EINVAL;
351 			}
352 		} else {
353 			error = -EPERM;
354 		}
355 		break;
356 
357 	case SNAPSHOT_S2RAM:
358 		if (!data->frozen) {
359 			error = -EPERM;
360 			break;
361 		}
362 		/*
363 		 * Tasks are frozen and the notifiers have been called with
364 		 * PM_HIBERNATION_PREPARE
365 		 */
366 		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
367 		break;
368 
369 	case SNAPSHOT_PLATFORM_SUPPORT:
370 		data->platform_support = !!arg;
371 		break;
372 
373 	case SNAPSHOT_POWER_OFF:
374 		if (data->platform_support)
375 			error = hibernation_platform_enter();
376 		break;
377 
378 	case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
379 		snapshot_deprecated_ioctl(cmd);
380 		error = -EINVAL;
381 
382 		switch (arg) {
383 
384 		case PMOPS_PREPARE:
385 			data->platform_support = 1;
386 			error = 0;
387 			break;
388 
389 		case PMOPS_ENTER:
390 			if (data->platform_support)
391 				error = hibernation_platform_enter();
392 			break;
393 
394 		case PMOPS_FINISH:
395 			if (data->platform_support)
396 				error = 0;
397 			break;
398 
399 		default:
400 			printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
401 
402 		}
403 		break;
404 
405 	case SNAPSHOT_SET_SWAP_AREA:
406 		if (swsusp_swap_in_use()) {
407 			error = -EPERM;
408 		} else {
409 			struct resume_swap_area swap_area;
410 			dev_t swdev;
411 
412 			error = copy_from_user(&swap_area, (void __user *)arg,
413 					sizeof(struct resume_swap_area));
414 			if (error) {
415 				error = -EFAULT;
416 				break;
417 			}
418 
419 			/*
420 			 * User space encodes device types as two-byte values,
421 			 * so we need to recode them
422 			 */
423 			swdev = new_decode_dev(swap_area.dev);
424 			if (swdev) {
425 				offset = swap_area.offset;
426 				data->swap = swap_type_of(swdev, offset, NULL);
427 				if (data->swap < 0)
428 					error = -ENODEV;
429 			} else {
430 				data->swap = -1;
431 				error = -EINVAL;
432 			}
433 		}
434 		break;
435 
436 	default:
437 		error = -ENOTTY;
438 
439 	}
440 
441 	mutex_unlock(&pm_mutex);
442 
443 	return error;
444 }
445 
446 static const struct file_operations snapshot_fops = {
447 	.open = snapshot_open,
448 	.release = snapshot_release,
449 	.read = snapshot_read,
450 	.write = snapshot_write,
451 	.llseek = no_llseek,
452 	.unlocked_ioctl = snapshot_ioctl,
453 };
454 
455 static struct miscdevice snapshot_device = {
456 	.minor = SNAPSHOT_MINOR,
457 	.name = "snapshot",
458 	.fops = &snapshot_fops,
459 };
460 
461 static int __init snapshot_device_init(void)
462 {
463 	return misc_register(&snapshot_device);
464 };
465 
466 device_initcall(snapshot_device_init);
467