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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/suspend.h>#include <linux/reboot.h>#include <linux/string.h>#include <linux/device.h>#include <linux/miscdevice.h>#include <linux/mm.h>#include <linux/swap.h>#include <linux/swapops.h>#include <linux/pm.h>#include <linux/fs.h>#include <linux/compat.h>#include <linux/console.h>#include <linux/cpu.h>#include <linux/freezer.h>
#include <linux/uaccess.h>
#include "power.h"
static bool need_wait;
static struct snapshot_data { struct snapshot_handle handle; int swap; int mode; bool frozen; bool ready; bool platform_support; bool free_bitmaps; dev_t dev;} snapshot_state;
int is_hibernate_resume_dev(dev_t dev){ return hibernation_available() && snapshot_state.dev == dev;}
static int snapshot_open(struct inode *inode, struct file *filp){ struct snapshot_data *data; unsigned int sleep_flags; int error;
if (!hibernation_available()) return -EPERM;
sleep_flags = lock_system_sleep();
if (!hibernate_acquire()) { error = -EBUSY; goto Unlock; }
if ((filp->f_flags & O_ACCMODE) == O_RDWR) { hibernate_release(); error = -ENOSYS; goto Unlock; } nonseekable_open(inode, filp); data = &snapshot_state; filp->private_data = data; memset(&data->handle, 0, sizeof(struct snapshot_handle)); if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { /* Hibernating. The image device should be accessible. */ data->swap = pin_hibernation_swap_type(swsusp_resume_device, 0); data->mode = O_RDONLY; data->free_bitmaps = false; error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION); } else { /* * Resuming. We may need to wait for the image device to * appear. */ need_wait = true;
data->swap = -1; data->mode = O_WRONLY; error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE); if (!error) { error = create_basic_memory_bitmaps(); data->free_bitmaps = !error; } } if (error) { unpin_hibernation_swap_type(data->swap); hibernate_release(); }
data->frozen = false; data->ready = false; data->platform_support = false; data->dev = 0;
Unlock: unlock_system_sleep(sleep_flags);
return error;}
static int snapshot_release(struct inode *inode, struct file *filp){ struct snapshot_data *data; unsigned int sleep_flags;
sleep_flags = lock_system_sleep();
swsusp_free(); data = filp->private_data; data->dev = 0; free_all_swap_pages(data->swap); unpin_hibernation_swap_type(data->swap); if (data->frozen) { pm_restore_gfp_mask(); free_basic_memory_bitmaps(); thaw_processes(); } else if (data->free_bitmaps) { free_basic_memory_bitmaps(); } pm_notifier_call_chain(data->mode == O_RDONLY ? PM_POST_HIBERNATION : PM_POST_RESTORE); hibernate_release();
unlock_system_sleep(sleep_flags);
return 0;}
static ssize_t snapshot_read(struct file *filp, char __user *buf, size_t count, loff_t *offp){ loff_t pg_offp = *offp & ~PAGE_MASK; struct snapshot_data *data; unsigned int sleep_flags; ssize_t res;
sleep_flags = lock_system_sleep();
data = filp->private_data; if (!data->ready) { res = -ENODATA; goto Unlock; } if (!pg_offp) { /* on page boundary? */ res = snapshot_read_next(&data->handle); if (res <= 0) goto Unlock; } else { res = PAGE_SIZE - pg_offp; }
res = simple_read_from_buffer(buf, count, &pg_offp, data_of(data->handle), res); if (res > 0) *offp += res;
Unlock: unlock_system_sleep(sleep_flags);
return res;}
static ssize_t snapshot_write(struct file *filp, const char __user *buf, size_t count, loff_t *offp){ loff_t pg_offp = *offp & ~PAGE_MASK; struct snapshot_data *data; unsigned long sleep_flags; ssize_t res;
if (need_wait) { wait_for_device_probe(); need_wait = false; }
sleep_flags = lock_system_sleep();
data = filp->private_data;
if (!pg_offp) { res = snapshot_write_next(&data->handle); if (res <= 0) goto unlock; } else { res = PAGE_SIZE; }
if (!data_of(data->handle)) { res = -EINVAL; goto unlock; }
res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp, buf, count); if (res > 0) *offp += res;unlock: unlock_system_sleep(sleep_flags);
return res;}
struct compat_resume_swap_area { compat_loff_t offset; u32 dev;} __packed;
static int snapshot_set_swap_area(struct snapshot_data *data, void __user *argp){ sector_t offset; dev_t swdev;
if (swsusp_swap_in_use()) return -EPERM;
if (in_compat_syscall()) { struct compat_resume_swap_area swap_area;
if (copy_from_user(&swap_area, argp, sizeof(swap_area))) return -EFAULT; swdev = new_decode_dev(swap_area.dev); offset = swap_area.offset; } else { struct resume_swap_area swap_area;
if (copy_from_user(&swap_area, argp, sizeof(swap_area))) return -EFAULT; swdev = new_decode_dev(swap_area.dev); offset = swap_area.offset; }
/* * Unpin the swap device if a swap area was already * set by SNAPSHOT_SET_SWAP_AREA. */ unpin_hibernation_swap_type(data->swap);
/* * User space encodes device types as two-byte values, * so we need to recode them */ data->swap = pin_hibernation_swap_type(swdev, offset); if (data->swap < 0) return swdev ? -ENODEV : -EINVAL; data->dev = swdev; return 0;}
static long snapshot_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){ int error = 0; struct snapshot_data *data; loff_t size; sector_t offset;
if (need_wait) { wait_for_device_probe(); need_wait = false; }
if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) return -ENOTTY; if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) return -ENOTTY; if (!capable(CAP_SYS_ADMIN)) return -EPERM;
if (!mutex_trylock(&system_transition_mutex)) return -EBUSY;
lock_device_hotplug(); data = filp->private_data;
switch (cmd) {
case SNAPSHOT_FREEZE: if (data->frozen) break;
error = pm_sleep_fs_sync(); if (error) break;
error = freeze_processes(); if (error) break;
error = create_basic_memory_bitmaps(); if (error) thaw_processes(); else data->frozen = true;
break;
case SNAPSHOT_UNFREEZE: if (!data->frozen || data->ready) break; pm_restore_gfp_mask(); free_basic_memory_bitmaps(); data->free_bitmaps = false; thaw_processes(); data->frozen = false; break;
case SNAPSHOT_CREATE_IMAGE: if (data->mode != O_RDONLY || !data->frozen || data->ready) { error = -EPERM; break; } pm_restore_gfp_mask(); error = hibernation_snapshot(data->platform_support); if (!error) { error = put_user(in_suspend, (int __user *)arg); data->ready = !freezer_test_done && !error; freezer_test_done = false; } break;
case SNAPSHOT_ATOMIC_RESTORE: error = snapshot_write_finalize(&data->handle); if (error) break; if (data->mode != O_WRONLY || !data->frozen) { error = -EPERM; break; } if (!snapshot_image_loaded(&data->handle)) { error = -ENODATA; break; } error = hibernation_restore(data->platform_support); break;
case SNAPSHOT_FREE: swsusp_free(); memset(&data->handle, 0, sizeof(struct snapshot_handle)); data->ready = false; /* * It is necessary to thaw kernel threads here, because * SNAPSHOT_CREATE_IMAGE may be invoked directly after * SNAPSHOT_FREE. In that case, if kernel threads were not * thawed, the preallocation of memory carried out by * hibernation_snapshot() might run into problems (i.e. it * might fail or even deadlock). */ thaw_kernel_threads(); break;
case SNAPSHOT_PREF_IMAGE_SIZE: image_size = arg; break;
case SNAPSHOT_GET_IMAGE_SIZE: if (!data->ready) { error = -ENODATA; break; } size = snapshot_get_image_size(); size <<= PAGE_SHIFT; error = put_user(size, (loff_t __user *)arg); break;
case SNAPSHOT_AVAIL_SWAP_SIZE: size = count_swap_pages(data->swap, 1); size <<= PAGE_SHIFT; error = put_user(size, (loff_t __user *)arg); break;
case SNAPSHOT_ALLOC_SWAP_PAGE: if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { error = -ENODEV; break; } offset = alloc_swapdev_block(data->swap); if (offset) { offset <<= PAGE_SHIFT; error = put_user(offset, (loff_t __user *)arg); } else { error = -ENOSPC; } break;
case SNAPSHOT_FREE_SWAP_PAGES: if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { error = -ENODEV; break; } free_all_swap_pages(data->swap); break;
case SNAPSHOT_S2RAM: if (!data->frozen) { error = -EPERM; break; } /* * Tasks are frozen and the notifiers have been called with * PM_HIBERNATION_PREPARE */ error = suspend_devices_and_enter(PM_SUSPEND_MEM); data->ready = false; break;
case SNAPSHOT_PLATFORM_SUPPORT: data->platform_support = !!arg; break;
case SNAPSHOT_POWER_OFF: if (data->platform_support) error = hibernation_platform_enter(); break;
case SNAPSHOT_SET_SWAP_AREA: error = snapshot_set_swap_area(data, (void __user *)arg); break;
default: error = -ENOTTY;
}
unlock_device_hotplug(); mutex_unlock(&system_transition_mutex);
return error;}
#ifdef CONFIG_COMPATstatic longsnapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg){ BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
switch (cmd) { case SNAPSHOT_GET_IMAGE_SIZE: case SNAPSHOT_AVAIL_SWAP_SIZE: case SNAPSHOT_ALLOC_SWAP_PAGE: case SNAPSHOT_CREATE_IMAGE: case SNAPSHOT_SET_SWAP_AREA: return snapshot_ioctl(file, cmd, (unsigned long) compat_ptr(arg)); default: return snapshot_ioctl(file, cmd, arg); }}#endif /* CONFIG_COMPAT */
static const struct file_operations snapshot_fops = { .open = snapshot_open, .release = snapshot_release, .read = snapshot_read, .write = snapshot_write, .unlocked_ioctl = snapshot_ioctl,#ifdef CONFIG_COMPAT .compat_ioctl = snapshot_compat_ioctl,#endif};
static struct miscdevice snapshot_device = { .minor = SNAPSHOT_MINOR, .name = "snapshot", .fops = &snapshot_fops,};
static int __init snapshot_device_init(void){ return misc_register(&snapshot_device);};
device_initcall(snapshot_device_init);