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 long snapshot_ioctl(struct file *filp, unsigned int cmd, 199 unsigned long arg) 200 { 201 int error = 0; 202 struct snapshot_data *data; 203 loff_t size; 204 sector_t offset; 205 206 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 207 return -ENOTTY; 208 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 209 return -ENOTTY; 210 if (!capable(CAP_SYS_ADMIN)) 211 return -EPERM; 212 213 if (!mutex_trylock(&pm_mutex)) 214 return -EBUSY; 215 216 data = filp->private_data; 217 218 switch (cmd) { 219 220 case SNAPSHOT_FREEZE: 221 if (data->frozen) 222 break; 223 224 printk("Syncing filesystems ... "); 225 sys_sync(); 226 printk("done.\n"); 227 228 error = usermodehelper_disable(); 229 if (error) 230 break; 231 232 error = freeze_processes(); 233 if (error) { 234 thaw_processes(); 235 usermodehelper_enable(); 236 } 237 if (!error) 238 data->frozen = 1; 239 break; 240 241 case SNAPSHOT_UNFREEZE: 242 if (!data->frozen || data->ready) 243 break; 244 thaw_processes(); 245 usermodehelper_enable(); 246 data->frozen = 0; 247 break; 248 249 case SNAPSHOT_CREATE_IMAGE: 250 case SNAPSHOT_ATOMIC_SNAPSHOT: 251 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 252 error = -EPERM; 253 break; 254 } 255 error = hibernation_snapshot(data->platform_support); 256 if (!error) 257 error = put_user(in_suspend, (int __user *)arg); 258 if (!error) 259 data->ready = 1; 260 break; 261 262 case SNAPSHOT_ATOMIC_RESTORE: 263 snapshot_write_finalize(&data->handle); 264 if (data->mode != O_WRONLY || !data->frozen || 265 !snapshot_image_loaded(&data->handle)) { 266 error = -EPERM; 267 break; 268 } 269 error = hibernation_restore(data->platform_support); 270 break; 271 272 case SNAPSHOT_FREE: 273 swsusp_free(); 274 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 275 data->ready = 0; 276 break; 277 278 case SNAPSHOT_PREF_IMAGE_SIZE: 279 case SNAPSHOT_SET_IMAGE_SIZE: 280 image_size = arg; 281 break; 282 283 case SNAPSHOT_GET_IMAGE_SIZE: 284 if (!data->ready) { 285 error = -ENODATA; 286 break; 287 } 288 size = snapshot_get_image_size(); 289 size <<= PAGE_SHIFT; 290 error = put_user(size, (loff_t __user *)arg); 291 break; 292 293 case SNAPSHOT_AVAIL_SWAP_SIZE: 294 case SNAPSHOT_AVAIL_SWAP: 295 size = count_swap_pages(data->swap, 1); 296 size <<= PAGE_SHIFT; 297 error = put_user(size, (loff_t __user *)arg); 298 break; 299 300 case SNAPSHOT_ALLOC_SWAP_PAGE: 301 case SNAPSHOT_GET_SWAP_PAGE: 302 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 303 error = -ENODEV; 304 break; 305 } 306 offset = alloc_swapdev_block(data->swap); 307 if (offset) { 308 offset <<= PAGE_SHIFT; 309 error = put_user(offset, (loff_t __user *)arg); 310 } else { 311 error = -ENOSPC; 312 } 313 break; 314 315 case SNAPSHOT_FREE_SWAP_PAGES: 316 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 317 error = -ENODEV; 318 break; 319 } 320 free_all_swap_pages(data->swap); 321 break; 322 323 case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */ 324 if (!swsusp_swap_in_use()) { 325 /* 326 * User space encodes device types as two-byte values, 327 * so we need to recode them 328 */ 329 if (old_decode_dev(arg)) { 330 data->swap = swap_type_of(old_decode_dev(arg), 331 0, NULL); 332 if (data->swap < 0) 333 error = -ENODEV; 334 } else { 335 data->swap = -1; 336 error = -EINVAL; 337 } 338 } else { 339 error = -EPERM; 340 } 341 break; 342 343 case SNAPSHOT_S2RAM: 344 if (!data->frozen) { 345 error = -EPERM; 346 break; 347 } 348 /* 349 * Tasks are frozen and the notifiers have been called with 350 * PM_HIBERNATION_PREPARE 351 */ 352 error = suspend_devices_and_enter(PM_SUSPEND_MEM); 353 break; 354 355 case SNAPSHOT_PLATFORM_SUPPORT: 356 data->platform_support = !!arg; 357 break; 358 359 case SNAPSHOT_POWER_OFF: 360 if (data->platform_support) 361 error = hibernation_platform_enter(); 362 break; 363 364 case SNAPSHOT_PMOPS: /* This ioctl is deprecated */ 365 error = -EINVAL; 366 367 switch (arg) { 368 369 case PMOPS_PREPARE: 370 data->platform_support = 1; 371 error = 0; 372 break; 373 374 case PMOPS_ENTER: 375 if (data->platform_support) 376 error = hibernation_platform_enter(); 377 break; 378 379 case PMOPS_FINISH: 380 if (data->platform_support) 381 error = 0; 382 break; 383 384 default: 385 printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg); 386 387 } 388 break; 389 390 case SNAPSHOT_SET_SWAP_AREA: 391 if (swsusp_swap_in_use()) { 392 error = -EPERM; 393 } else { 394 struct resume_swap_area swap_area; 395 dev_t swdev; 396 397 error = copy_from_user(&swap_area, (void __user *)arg, 398 sizeof(struct resume_swap_area)); 399 if (error) { 400 error = -EFAULT; 401 break; 402 } 403 404 /* 405 * User space encodes device types as two-byte values, 406 * so we need to recode them 407 */ 408 swdev = old_decode_dev(swap_area.dev); 409 if (swdev) { 410 offset = swap_area.offset; 411 data->swap = swap_type_of(swdev, offset, NULL); 412 if (data->swap < 0) 413 error = -ENODEV; 414 } else { 415 data->swap = -1; 416 error = -EINVAL; 417 } 418 } 419 break; 420 421 default: 422 error = -ENOTTY; 423 424 } 425 426 mutex_unlock(&pm_mutex); 427 428 return error; 429 } 430 431 static const struct file_operations snapshot_fops = { 432 .open = snapshot_open, 433 .release = snapshot_release, 434 .read = snapshot_read, 435 .write = snapshot_write, 436 .llseek = no_llseek, 437 .unlocked_ioctl = snapshot_ioctl, 438 }; 439 440 static struct miscdevice snapshot_device = { 441 .minor = SNAPSHOT_MINOR, 442 .name = "snapshot", 443 .fops = &snapshot_fops, 444 }; 445 446 static int __init snapshot_device_init(void) 447 { 448 return misc_register(&snapshot_device); 449 }; 450 451 device_initcall(snapshot_device_init); 452