Root/kernel/power/user.c

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
57static 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
66atomic_t snapshot_device_available = ATOMIC_INIT(1);
67
68static 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        free_basic_memory_bitmaps();
118        atomic_inc(&snapshot_device_available);
119    }
120    data->frozen = 0;
121    data->ready = 0;
122    data->platform_support = 0;
123
124 Unlock:
125    mutex_unlock(&pm_mutex);
126
127    return error;
128}
129
130static int snapshot_release(struct inode *inode, struct file *filp)
131{
132    struct snapshot_data *data;
133
134    mutex_lock(&pm_mutex);
135
136    swsusp_free();
137    free_basic_memory_bitmaps();
138    data = filp->private_data;
139    free_all_swap_pages(data->swap);
140    if (data->frozen) {
141        pm_restore_gfp_mask();
142        thaw_processes();
143    }
144    pm_notifier_call_chain(data->mode == O_RDONLY ?
145            PM_POST_HIBERNATION : PM_POST_RESTORE);
146    atomic_inc(&snapshot_device_available);
147
148    mutex_unlock(&pm_mutex);
149
150    return 0;
151}
152
153static ssize_t snapshot_read(struct file *filp, char __user *buf,
154                             size_t count, loff_t *offp)
155{
156    struct snapshot_data *data;
157    ssize_t res;
158    loff_t pg_offp = *offp & ~PAGE_MASK;
159
160    mutex_lock(&pm_mutex);
161
162    data = filp->private_data;
163    if (!data->ready) {
164        res = -ENODATA;
165        goto Unlock;
166    }
167    if (!pg_offp) { /* on page boundary? */
168        res = snapshot_read_next(&data->handle);
169        if (res <= 0)
170            goto Unlock;
171    } else {
172        res = PAGE_SIZE - pg_offp;
173    }
174
175    res = simple_read_from_buffer(buf, count, &pg_offp,
176            data_of(data->handle), res);
177    if (res > 0)
178        *offp += res;
179
180 Unlock:
181    mutex_unlock(&pm_mutex);
182
183    return res;
184}
185
186static ssize_t snapshot_write(struct file *filp, const char __user *buf,
187                              size_t count, loff_t *offp)
188{
189    struct snapshot_data *data;
190    ssize_t res;
191    loff_t pg_offp = *offp & ~PAGE_MASK;
192
193    mutex_lock(&pm_mutex);
194
195    data = filp->private_data;
196
197    if (!pg_offp) {
198        res = snapshot_write_next(&data->handle);
199        if (res <= 0)
200            goto unlock;
201    } else {
202        res = PAGE_SIZE - pg_offp;
203    }
204
205    res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
206            buf, count);
207    if (res > 0)
208        *offp += res;
209unlock:
210    mutex_unlock(&pm_mutex);
211
212    return res;
213}
214
215static void snapshot_deprecated_ioctl(unsigned int cmd)
216{
217    if (printk_ratelimit())
218        printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
219                "be removed soon, update your suspend-to-disk "
220                "utilities\n",
221                __builtin_return_address(0), cmd);
222}
223
224static long snapshot_ioctl(struct file *filp, unsigned int cmd,
225                            unsigned long arg)
226{
227    int error = 0;
228    struct snapshot_data *data;
229    loff_t size;
230    sector_t offset;
231
232    if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
233        return -ENOTTY;
234    if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
235        return -ENOTTY;
236    if (!capable(CAP_SYS_ADMIN))
237        return -EPERM;
238
239    if (!mutex_trylock(&pm_mutex))
240        return -EBUSY;
241
242    data = filp->private_data;
243
244    switch (cmd) {
245
246    case SNAPSHOT_FREEZE:
247        if (data->frozen)
248            break;
249
250        printk("Syncing filesystems ... ");
251        sys_sync();
252        printk("done.\n");
253
254        error = usermodehelper_disable();
255        if (error)
256            break;
257
258        error = freeze_processes();
259        if (error) {
260            thaw_processes();
261            usermodehelper_enable();
262        }
263        if (!error)
264            data->frozen = 1;
265        break;
266
267    case SNAPSHOT_UNFREEZE:
268        if (!data->frozen || data->ready)
269            break;
270        pm_restore_gfp_mask();
271        thaw_processes();
272        usermodehelper_enable();
273        data->frozen = 0;
274        break;
275
276    case SNAPSHOT_ATOMIC_SNAPSHOT:
277        snapshot_deprecated_ioctl(cmd);
278    case SNAPSHOT_CREATE_IMAGE:
279        if (data->mode != O_RDONLY || !data->frozen || data->ready) {
280            error = -EPERM;
281            break;
282        }
283        pm_restore_gfp_mask();
284        error = hibernation_snapshot(data->platform_support);
285        if (!error)
286            error = put_user(in_suspend, (int __user *)arg);
287        if (!error)
288            data->ready = 1;
289        break;
290
291    case SNAPSHOT_ATOMIC_RESTORE:
292        snapshot_write_finalize(&data->handle);
293        if (data->mode != O_WRONLY || !data->frozen ||
294            !snapshot_image_loaded(&data->handle)) {
295            error = -EPERM;
296            break;
297        }
298        error = hibernation_restore(data->platform_support);
299        break;
300
301    case SNAPSHOT_FREE:
302        swsusp_free();
303        memset(&data->handle, 0, sizeof(struct snapshot_handle));
304        data->ready = 0;
305        break;
306
307    case SNAPSHOT_SET_IMAGE_SIZE:
308        snapshot_deprecated_ioctl(cmd);
309    case SNAPSHOT_PREF_IMAGE_SIZE:
310        image_size = arg;
311        break;
312
313    case SNAPSHOT_GET_IMAGE_SIZE:
314        if (!data->ready) {
315            error = -ENODATA;
316            break;
317        }
318        size = snapshot_get_image_size();
319        size <<= PAGE_SHIFT;
320        error = put_user(size, (loff_t __user *)arg);
321        break;
322
323    case SNAPSHOT_AVAIL_SWAP:
324        snapshot_deprecated_ioctl(cmd);
325    case SNAPSHOT_AVAIL_SWAP_SIZE:
326        size = count_swap_pages(data->swap, 1);
327        size <<= PAGE_SHIFT;
328        error = put_user(size, (loff_t __user *)arg);
329        break;
330
331    case SNAPSHOT_GET_SWAP_PAGE:
332        snapshot_deprecated_ioctl(cmd);
333    case SNAPSHOT_ALLOC_SWAP_PAGE:
334        if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
335            error = -ENODEV;
336            break;
337        }
338        offset = alloc_swapdev_block(data->swap);
339        if (offset) {
340            offset <<= PAGE_SHIFT;
341            error = put_user(offset, (loff_t __user *)arg);
342        } else {
343            error = -ENOSPC;
344        }
345        break;
346
347    case SNAPSHOT_FREE_SWAP_PAGES:
348        if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
349            error = -ENODEV;
350            break;
351        }
352        free_all_swap_pages(data->swap);
353        break;
354
355    case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
356        snapshot_deprecated_ioctl(cmd);
357        if (!swsusp_swap_in_use()) {
358            /*
359             * User space encodes device types as two-byte values,
360             * so we need to recode them
361             */
362            if (old_decode_dev(arg)) {
363                data->swap = swap_type_of(old_decode_dev(arg),
364                            0, NULL);
365                if (data->swap < 0)
366                    error = -ENODEV;
367            } else {
368                data->swap = -1;
369                error = -EINVAL;
370            }
371        } else {
372            error = -EPERM;
373        }
374        break;
375
376    case SNAPSHOT_S2RAM:
377        if (!data->frozen) {
378            error = -EPERM;
379            break;
380        }
381        /*
382         * Tasks are frozen and the notifiers have been called with
383         * PM_HIBERNATION_PREPARE
384         */
385        error = suspend_devices_and_enter(PM_SUSPEND_MEM);
386        data->ready = 0;
387        break;
388
389    case SNAPSHOT_PLATFORM_SUPPORT:
390        data->platform_support = !!arg;
391        break;
392
393    case SNAPSHOT_POWER_OFF:
394        if (data->platform_support)
395            error = hibernation_platform_enter();
396        break;
397
398    case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
399        snapshot_deprecated_ioctl(cmd);
400        error = -EINVAL;
401
402        switch (arg) {
403
404        case PMOPS_PREPARE:
405            data->platform_support = 1;
406            error = 0;
407            break;
408
409        case PMOPS_ENTER:
410            if (data->platform_support)
411                error = hibernation_platform_enter();
412            break;
413
414        case PMOPS_FINISH:
415            if (data->platform_support)
416                error = 0;
417            break;
418
419        default:
420            printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
421
422        }
423        break;
424
425    case SNAPSHOT_SET_SWAP_AREA:
426        if (swsusp_swap_in_use()) {
427            error = -EPERM;
428        } else {
429            struct resume_swap_area swap_area;
430            dev_t swdev;
431
432            error = copy_from_user(&swap_area, (void __user *)arg,
433                    sizeof(struct resume_swap_area));
434            if (error) {
435                error = -EFAULT;
436                break;
437            }
438
439            /*
440             * User space encodes device types as two-byte values,
441             * so we need to recode them
442             */
443            swdev = new_decode_dev(swap_area.dev);
444            if (swdev) {
445                offset = swap_area.offset;
446                data->swap = swap_type_of(swdev, offset, NULL);
447                if (data->swap < 0)
448                    error = -ENODEV;
449            } else {
450                data->swap = -1;
451                error = -EINVAL;
452            }
453        }
454        break;
455
456    default:
457        error = -ENOTTY;
458
459    }
460
461    mutex_unlock(&pm_mutex);
462
463    return error;
464}
465
466static const struct file_operations snapshot_fops = {
467    .open = snapshot_open,
468    .release = snapshot_release,
469    .read = snapshot_read,
470    .write = snapshot_write,
471    .llseek = no_llseek,
472    .unlocked_ioctl = snapshot_ioctl,
473};
474
475static struct miscdevice snapshot_device = {
476    .minor = SNAPSHOT_MINOR,
477    .name = "snapshot",
478    .fops = &snapshot_fops,
479};
480
481static int __init snapshot_device_init(void)
482{
483    return misc_register(&snapshot_device);
484};
485
486device_initcall(snapshot_device_init);
487

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