fs/proc/inode.c - hafnium/third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/proc/inode.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */

 #include <linux/cache.h>
 #include <linux/time.h>
 #include <linux/proc_fs.h>
 #include <linux/kernel.h>
 #include <linux/pid_namespace.h>
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/stat.h>
 #include <linux/completion.h>
 #include <linux/poll.h>
 #include <linux/printk.h>
 #include <linux/file.h>
 #include <linux/limits.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/sysctl.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/mount.h>

 #include <linux/uaccess.h>

 #include "internal.h"

 static void proc_evict_inode(struct inode *inode)
 {
 	struct proc_dir_entry *de;
 	struct ctl_table_header *head;

 	truncate_inode_pages_final(&inode->i_data);
 	clear_inode(inode);

 	/* Stop tracking associated processes */
 	put_pid(PROC_I(inode)->pid);

 	/* Let go of any associated proc directory entry */
 	de = PDE(inode);
 	if (de)
 		pde_put(de);

 	head = PROC_I(inode)->sysctl;
 	if (head) {
 		RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL);
 		proc_sys_evict_inode(inode, head);
 	}
 }

 static struct kmem_cache *proc_inode_cachep __ro_after_init;
 static struct kmem_cache *pde_opener_cache __ro_after_init;

 static struct inode *proc_alloc_inode(struct super_block *sb)
 {
 	struct proc_inode *ei;

 	ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
 	if (!ei)
 		return NULL;
 	ei->pid = NULL;
 	ei->fd = 0;
 	ei->op.proc_get_link = NULL;
 	ei->pde = NULL;
 	ei->sysctl = NULL;
 	ei->sysctl_entry = NULL;
 	ei->ns_ops = NULL;
 	return &ei->vfs_inode;
 }

 static void proc_free_inode(struct inode *inode)
 {
 	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
 }

 static void init_once(void *foo)
 {
 	struct proc_inode *ei = (struct proc_inode *) foo;

 	inode_init_once(&ei->vfs_inode);
 }

 void __init proc_init_kmemcache(void)
 {
 	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
 					     sizeof(struct proc_inode),
 					     0, (SLAB_RECLAIM_ACCOUNT|
 						SLAB_MEM_SPREAD|SLAB_ACCOUNT|
 						SLAB_PANIC),
 					     init_once);
 	pde_opener_cache =
 		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
 				  SLAB_ACCOUNT|SLAB_PANIC, NULL);
 	proc_dir_entry_cache = kmem_cache_create_usercopy(
 		"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
 		offsetof(struct proc_dir_entry, inline_name),
 		SIZEOF_PDE_INLINE_NAME, NULL);
 	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
 }

 static int proc_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct super_block *sb = root->d_sb;
 	struct pid_namespace *pid = sb->s_fs_info;

 	if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
 		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
 	if (pid->hide_pid != HIDEPID_OFF)
 		seq_printf(seq, ",hidepid=%u", pid->hide_pid);

 	return 0;
 }

 const struct super_operations proc_sops = {
 	.alloc_inode	= proc_alloc_inode,
 	.free_inode	= proc_free_inode,
 	.drop_inode	= generic_delete_inode,
 	.evict_inode	= proc_evict_inode,
 	.statfs		= simple_statfs,
 	.show_options	= proc_show_options,
 };

 enum {BIAS = -1U<<31};

 static inline int use_pde(struct proc_dir_entry *pde)
 {
 	return likely(atomic_inc_unless_negative(&pde->in_use));
 }

 static void unuse_pde(struct proc_dir_entry *pde)
 {
 	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
 		complete(pde->pde_unload_completion);
 }

 /* pde is locked on entry, unlocked on exit */
 static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
 {
 	/*
 	 * close() (proc_reg_release()) can't delete an entry and proceed:
 	 * ->release hook needs to be available at the right moment.
 	 *
 	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
 	 * "struct file" needs to be available at the right moment.
 	 *
 	 * Therefore, first process to enter this function does ->release() and
 	 * signals its completion to the other process which does nothing.
 	 */
 	if (pdeo->closing) {
 		/* somebody else is doing that, just wait */
 		DECLARE_COMPLETION_ONSTACK(c);
 		pdeo->c = &c;
 		spin_unlock(&pde->pde_unload_lock);
 		wait_for_completion(&c);
 	} else {
 		struct file *file;
 		struct completion *c;

 		pdeo->closing = true;
 		spin_unlock(&pde->pde_unload_lock);
 		file = pdeo->file;
 		pde->proc_fops->release(file_inode(file), file);
 		spin_lock(&pde->pde_unload_lock);
 		/* After ->release. */
 		list_del(&pdeo->lh);
 		c = pdeo->c;
 		spin_unlock(&pde->pde_unload_lock);
 		if (unlikely(c))
 			complete(c);
 		kmem_cache_free(pde_opener_cache, pdeo);
 	}
 }

 void proc_entry_rundown(struct proc_dir_entry *de)
 {
 	DECLARE_COMPLETION_ONSTACK(c);
 	/* Wait until all existing callers into module are done. */
 	de->pde_unload_completion = &c;
 	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
 		wait_for_completion(&c);

 	/* ->pde_openers list can't grow from now on. */

 	spin_lock(&de->pde_unload_lock);
 	while (!list_empty(&de->pde_openers)) {
 		struct pde_opener *pdeo;
 		pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
 		close_pdeo(de, pdeo);
 		spin_lock(&de->pde_unload_lock);
 	}
 	spin_unlock(&de->pde_unload_lock);
 }

 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	loff_t rv = -EINVAL;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, llseek) llseek;

 		llseek = pde->proc_fops->llseek;
 		if (!llseek)
 			llseek = default_llseek;
 		rv = llseek(file, offset, whence);
 		unuse_pde(pde);
 	}
 	return rv;
 }

 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	ssize_t rv = -EIO;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, read) read;

 		read = pde->proc_fops->read;
 		if (read)
 			rv = read(file, buf, count, ppos);
 		unuse_pde(pde);
 	}
 	return rv;
 }

 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	ssize_t rv = -EIO;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, write) write;

 		write = pde->proc_fops->write;
 		if (write)
 			rv = write(file, buf, count, ppos);
 		unuse_pde(pde);
 	}
 	return rv;
 }

 static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	__poll_t rv = DEFAULT_POLLMASK;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, poll) poll;

 		poll = pde->proc_fops->poll;
 		if (poll)
 			rv = poll(file, pts);
 		unuse_pde(pde);
 	}
 	return rv;
 }

 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	long rv = -ENOTTY;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, unlocked_ioctl) ioctl;

 		ioctl = pde->proc_fops->unlocked_ioctl;
 		if (ioctl)
 			rv = ioctl(file, cmd, arg);
 		unuse_pde(pde);
 	}
 	return rv;
 }

 #ifdef CONFIG_COMPAT
 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	long rv = -ENOTTY;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, compat_ioctl) compat_ioctl;

 		compat_ioctl = pde->proc_fops->compat_ioctl;
 		if (compat_ioctl)
 			rv = compat_ioctl(file, cmd, arg);
 		unuse_pde(pde);
 	}
 	return rv;
 }
 #endif

 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	int rv = -EIO;
 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, mmap) mmap;

 		mmap = pde->proc_fops->mmap;
 		if (mmap)
 			rv = mmap(file, vma);
 		unuse_pde(pde);
 	}
 	return rv;
 }

 static unsigned long
 proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
 			   unsigned long len, unsigned long pgoff,
 			   unsigned long flags)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
 	unsigned long rv = -EIO;

 	if (use_pde(pde)) {
 		typeof_member(struct file_operations, get_unmapped_area) get_area;

 		get_area = pde->proc_fops->get_unmapped_area;
 #ifdef CONFIG_MMU
 		if (!get_area)
 			get_area = current->mm->get_unmapped_area;
 #endif

 		if (get_area)
 			rv = get_area(file, orig_addr, len, pgoff, flags);
 		else
 			rv = orig_addr;
 		unuse_pde(pde);
 	}
 	return rv;
 }

 static int proc_reg_open(struct inode *inode, struct file *file)
 {
 	struct proc_dir_entry *pde = PDE(inode);
 	int rv = 0;
 	typeof_member(struct file_operations, open) open;
 	typeof_member(struct file_operations, release) release;
 	struct pde_opener *pdeo;

 	/*
 	 * Ensure that
 	 * 1) PDE's ->release hook will be called no matter what
 	 *    either normally by close()/->release, or forcefully by
 	 *    rmmod/remove_proc_entry.
 	 *
 	 * 2) rmmod isn't blocked by opening file in /proc and sitting on
 	 *    the descriptor (including "rmmod foo </proc/foo" scenario).
 	 *
 	 * Save every "struct file" with custom ->release hook.
 	 */
 	if (!use_pde(pde))
 		return -ENOENT;

 	release = pde->proc_fops->release;
 	if (release) {
 		pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
 		if (!pdeo) {
 			rv = -ENOMEM;
 			goto out_unuse;
 		}
 	}

 	open = pde->proc_fops->open;
 	if (open)
 		rv = open(inode, file);

 	if (release) {
 		if (rv == 0) {
 			/* To know what to release. */
 			pdeo->file = file;
 			pdeo->closing = false;
 			pdeo->c = NULL;
 			spin_lock(&pde->pde_unload_lock);
 			list_add(&pdeo->lh, &pde->pde_openers);
 			spin_unlock(&pde->pde_unload_lock);
 		} else
 			kmem_cache_free(pde_opener_cache, pdeo);
 	}

 out_unuse:
 	unuse_pde(pde);
 	return rv;
 }

 static int proc_reg_release(struct inode *inode, struct file *file)
 {
 	struct proc_dir_entry *pde = PDE(inode);
 	struct pde_opener *pdeo;
 	spin_lock(&pde->pde_unload_lock);
 	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
 		if (pdeo->file == file) {
 			close_pdeo(pde, pdeo);
 			return 0;
 		}
 	}
 	spin_unlock(&pde->pde_unload_lock);
 	return 0;
 }

 static const struct file_operations proc_reg_file_ops = {
 	.llseek		= proc_reg_llseek,
 	.read		= proc_reg_read,
 	.write		= proc_reg_write,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= proc_reg_compat_ioctl,
 #endif
 	.mmap		= proc_reg_mmap,
 	.get_unmapped_area = proc_reg_get_unmapped_area,
 	.open		= proc_reg_open,
 	.release	= proc_reg_release,
 };

 #ifdef CONFIG_COMPAT
 static const struct file_operations proc_reg_file_ops_no_compat = {
 	.llseek		= proc_reg_llseek,
 	.read		= proc_reg_read,
 	.write		= proc_reg_write,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
 	.mmap		= proc_reg_mmap,
 	.get_unmapped_area = proc_reg_get_unmapped_area,
 	.open		= proc_reg_open,
 	.release	= proc_reg_release,
 };
 #endif

 static void proc_put_link(void *p)
 {
 	unuse_pde(p);
 }

 static const char *proc_get_link(struct dentry *dentry,
 				 struct inode *inode,
 				 struct delayed_call *done)
 {
 	struct proc_dir_entry *pde = PDE(inode);
 	if (!use_pde(pde))
 		return ERR_PTR(-EINVAL);
 	set_delayed_call(done, proc_put_link, pde);
 	return pde->data;
 }

 const struct inode_operations proc_link_inode_operations = {
 	.get_link	= proc_get_link,
 };

 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
 {
 	struct inode *inode = new_inode_pseudo(sb);

 	if (inode) {
 		inode->i_ino = de->low_ino;
 		inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 		PROC_I(inode)->pde = de;

 		if (is_empty_pde(de)) {
 			make_empty_dir_inode(inode);
 			return inode;
 		}
 		if (de->mode) {
 			inode->i_mode = de->mode;
 			inode->i_uid = de->uid;
 			inode->i_gid = de->gid;
 		}
 		if (de->size)
 			inode->i_size = de->size;
 		if (de->nlink)
 			set_nlink(inode, de->nlink);
 		WARN_ON(!de->proc_iops);
 		inode->i_op = de->proc_iops;
 		if (de->proc_fops) {
 			if (S_ISREG(inode->i_mode)) {
 #ifdef CONFIG_COMPAT
 				if (!de->proc_fops->compat_ioctl)
 					inode->i_fop =
 						&proc_reg_file_ops_no_compat;
 				else
 #endif
 					inode->i_fop = &proc_reg_file_ops;
 			} else {
 				inode->i_fop = de->proc_fops;
 			}
 		}
 	} else
 	       pde_put(de);
 	return inode;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* linux/fs/proc/inode.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*/

	#include <linux/cache.h>
	#include <linux/time.h>
	#include <linux/proc_fs.h>
	#include <linux/kernel.h>
	#include <linux/pid_namespace.h>
	#include <linux/mm.h>
	#include <linux/string.h>
	#include <linux/stat.h>
	#include <linux/completion.h>
	#include <linux/poll.h>
	#include <linux/printk.h>
	#include <linux/file.h>
	#include <linux/limits.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/sysctl.h>
	#include <linux/seq_file.h>
	#include <linux/slab.h>
	#include <linux/mount.h>

	#include <linux/uaccess.h>

	#include "internal.h"

	static void proc_evict_inode(struct inode *inode)
	{
	struct proc_dir_entry *de;
	struct ctl_table_header *head;

	truncate_inode_pages_final(&inode->i_data);
	clear_inode(inode);

	/* Stop tracking associated processes */
	put_pid(PROC_I(inode)->pid);

	/* Let go of any associated proc directory entry */
	de = PDE(inode);
	if (de)
	pde_put(de);

	head = PROC_I(inode)->sysctl;
	if (head) {
	RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL);
	proc_sys_evict_inode(inode, head);
	}
	}

	static struct kmem_cache *proc_inode_cachep __ro_after_init;
	static struct kmem_cache *pde_opener_cache __ro_after_init;

	static struct inode proc_alloc_inode(struct super_block sb)
	{
	struct proc_inode *ei;

	ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
	if (!ei)
	return NULL;
	ei->pid = NULL;
	ei->fd = 0;
	ei->op.proc_get_link = NULL;
	ei->pde = NULL;
	ei->sysctl = NULL;
	ei->sysctl_entry = NULL;
	ei->ns_ops = NULL;
	return &ei->vfs_inode;
	}

	static void proc_free_inode(struct inode *inode)
	{
	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	}

	static void init_once(void *foo)
	{
	struct proc_inode ei = (struct proc_inode ) foo;

	inode_init_once(&ei->vfs_inode);
	}

	void __init proc_init_kmemcache(void)
	{
	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	sizeof(struct proc_inode),
	0, (SLAB_RECLAIM_ACCOUNT\|
	SLAB_MEM_SPREAD\|SLAB_ACCOUNT\|
	SLAB_PANIC),
	init_once);
	pde_opener_cache =
	kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
	SLAB_ACCOUNT\|SLAB_PANIC, NULL);
	proc_dir_entry_cache = kmem_cache_create_usercopy(
	"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
	offsetof(struct proc_dir_entry, inline_name),
	SIZEOF_PDE_INLINE_NAME, NULL);
	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
	}

	static int proc_show_options(struct seq_file seq, struct dentry root)
	{
	struct super_block *sb = root->d_sb;
	struct pid_namespace *pid = sb->s_fs_info;

	if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
	seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
	if (pid->hide_pid != HIDEPID_OFF)
	seq_printf(seq, ",hidepid=%u", pid->hide_pid);

	return 0;
	}

	const struct super_operations proc_sops = {
	.alloc_inode = proc_alloc_inode,
	.free_inode = proc_free_inode,
	.drop_inode = generic_delete_inode,
	.evict_inode = proc_evict_inode,
	.statfs = simple_statfs,
	.show_options = proc_show_options,
	};

	enum {BIAS = -1U<<31};

	static inline int use_pde(struct proc_dir_entry *pde)
	{
	return likely(atomic_inc_unless_negative(&pde->in_use));
	}

	static void unuse_pde(struct proc_dir_entry *pde)
	{
	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
	complete(pde->pde_unload_completion);
	}

	/* pde is locked on entry, unlocked on exit */
	static void close_pdeo(struct proc_dir_entry pde, struct pde_opener pdeo)
	{
	/*
	* close() (proc_reg_release()) can't delete an entry and proceed:
	* ->release hook needs to be available at the right moment.
	*
	* rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
	* "struct file" needs to be available at the right moment.
	*
	* Therefore, first process to enter this function does ->release() and
	* signals its completion to the other process which does nothing.
	*/
	if (pdeo->closing) {
	/* somebody else is doing that, just wait */
	DECLARE_COMPLETION_ONSTACK(c);
	pdeo->c = &c;
	spin_unlock(&pde->pde_unload_lock);
	wait_for_completion(&c);
	} else {
	struct file *file;
	struct completion *c;

	pdeo->closing = true;
	spin_unlock(&pde->pde_unload_lock);
	file = pdeo->file;
	pde->proc_fops->release(file_inode(file), file);
	spin_lock(&pde->pde_unload_lock);
	/* After ->release. */
	list_del(&pdeo->lh);
	c = pdeo->c;
	spin_unlock(&pde->pde_unload_lock);
	if (unlikely(c))
	complete(c);
	kmem_cache_free(pde_opener_cache, pdeo);
	}
	}

	void proc_entry_rundown(struct proc_dir_entry *de)
	{
	DECLARE_COMPLETION_ONSTACK(c);
	/* Wait until all existing callers into module are done. */
	de->pde_unload_completion = &c;
	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
	wait_for_completion(&c);

	/* ->pde_openers list can't grow from now on. */

	spin_lock(&de->pde_unload_lock);
	while (!list_empty(&de->pde_openers)) {
	struct pde_opener *pdeo;
	pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
	close_pdeo(de, pdeo);
	spin_lock(&de->pde_unload_lock);
	}
	spin_unlock(&de->pde_unload_lock);
	}

	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	loff_t rv = -EINVAL;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, llseek) llseek;

	llseek = pde->proc_fops->llseek;
	if (!llseek)
	llseek = default_llseek;
	rv = llseek(file, offset, whence);
	unuse_pde(pde);
	}
	return rv;
	}

	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	ssize_t rv = -EIO;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, read) read;

	read = pde->proc_fops->read;
	if (read)
	rv = read(file, buf, count, ppos);
	unuse_pde(pde);
	}
	return rv;
	}

	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	ssize_t rv = -EIO;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, write) write;

	write = pde->proc_fops->write;
	if (write)
	rv = write(file, buf, count, ppos);
	unuse_pde(pde);
	}
	return rv;
	}

	static __poll_t proc_reg_poll(struct file file, struct poll_table_struct pts)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	__poll_t rv = DEFAULT_POLLMASK;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, poll) poll;

	poll = pde->proc_fops->poll;
	if (poll)
	rv = poll(file, pts);
	unuse_pde(pde);
	}
	return rv;
	}

	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	long rv = -ENOTTY;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, unlocked_ioctl) ioctl;

	ioctl = pde->proc_fops->unlocked_ioctl;
	if (ioctl)
	rv = ioctl(file, cmd, arg);
	unuse_pde(pde);
	}
	return rv;
	}

	#ifdef CONFIG_COMPAT
	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	long rv = -ENOTTY;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, compat_ioctl) compat_ioctl;

	compat_ioctl = pde->proc_fops->compat_ioctl;
	if (compat_ioctl)
	rv = compat_ioctl(file, cmd, arg);
	unuse_pde(pde);
	}
	return rv;
	}
	#endif

	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	int rv = -EIO;
	if (use_pde(pde)) {
	typeof_member(struct file_operations, mmap) mmap;

	mmap = pde->proc_fops->mmap;
	if (mmap)
	rv = mmap(file, vma);
	unuse_pde(pde);
	}
	return rv;
	}

	static unsigned long
	proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
	unsigned long len, unsigned long pgoff,
	unsigned long flags)
	{
	struct proc_dir_entry *pde = PDE(file_inode(file));
	unsigned long rv = -EIO;

	if (use_pde(pde)) {
	typeof_member(struct file_operations, get_unmapped_area) get_area;

	get_area = pde->proc_fops->get_unmapped_area;
	#ifdef CONFIG_MMU
	if (!get_area)
	get_area = current->mm->get_unmapped_area;
	#endif

	if (get_area)
	rv = get_area(file, orig_addr, len, pgoff, flags);
	else
	rv = orig_addr;
	unuse_pde(pde);
	}
	return rv;
	}

	static int proc_reg_open(struct inode inode, struct file file)
	{
	struct proc_dir_entry *pde = PDE(inode);
	int rv = 0;
	typeof_member(struct file_operations, open) open;
	typeof_member(struct file_operations, release) release;
	struct pde_opener *pdeo;

	/*
	* Ensure that
	* 1) PDE's ->release hook will be called no matter what
	* either normally by close()/->release, or forcefully by
	* rmmod/remove_proc_entry.
	*
	* 2) rmmod isn't blocked by opening file in /proc and sitting on
	* the descriptor (including "rmmod foo </proc/foo" scenario).
	*
	* Save every "struct file" with custom ->release hook.
	*/
	if (!use_pde(pde))
	return -ENOENT;

	release = pde->proc_fops->release;
	if (release) {
	pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
	if (!pdeo) {
	rv = -ENOMEM;
	goto out_unuse;
	}
	}

	open = pde->proc_fops->open;
	if (open)
	rv = open(inode, file);

	if (release) {
	if (rv == 0) {
	/* To know what to release. */
	pdeo->file = file;
	pdeo->closing = false;
	pdeo->c = NULL;
	spin_lock(&pde->pde_unload_lock);
	list_add(&pdeo->lh, &pde->pde_openers);
	spin_unlock(&pde->pde_unload_lock);
	} else
	kmem_cache_free(pde_opener_cache, pdeo);
	}

	out_unuse:
	unuse_pde(pde);
	return rv;
	}

	static int proc_reg_release(struct inode inode, struct file file)
	{
	struct proc_dir_entry *pde = PDE(inode);
	struct pde_opener *pdeo;
	spin_lock(&pde->pde_unload_lock);
	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	if (pdeo->file == file) {
	close_pdeo(pde, pdeo);
	return 0;
	}
	}
	spin_unlock(&pde->pde_unload_lock);
	return 0;
	}

	static const struct file_operations proc_reg_file_ops = {
	.llseek = proc_reg_llseek,
	.read = proc_reg_read,
	.write = proc_reg_write,
	.poll = proc_reg_poll,
	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	#ifdef CONFIG_COMPAT
	.compat_ioctl = proc_reg_compat_ioctl,
	#endif
	.mmap = proc_reg_mmap,
	.get_unmapped_area = proc_reg_get_unmapped_area,
	.open = proc_reg_open,
	.release = proc_reg_release,
	};

	#ifdef CONFIG_COMPAT
	static const struct file_operations proc_reg_file_ops_no_compat = {
	.llseek = proc_reg_llseek,
	.read = proc_reg_read,
	.write = proc_reg_write,
	.poll = proc_reg_poll,
	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	.mmap = proc_reg_mmap,
	.get_unmapped_area = proc_reg_get_unmapped_area,
	.open = proc_reg_open,
	.release = proc_reg_release,
	};
	#endif

	static void proc_put_link(void *p)
	{
	unuse_pde(p);
	}

	static const char proc_get_link(struct dentry dentry,
	struct inode *inode,
	struct delayed_call *done)
	{
	struct proc_dir_entry *pde = PDE(inode);
	if (!use_pde(pde))
	return ERR_PTR(-EINVAL);
	set_delayed_call(done, proc_put_link, pde);
	return pde->data;
	}

	const struct inode_operations proc_link_inode_operations = {
	.get_link = proc_get_link,
	};

	struct inode proc_get_inode(struct super_block sb, struct proc_dir_entry *de)
	{
	struct inode *inode = new_inode_pseudo(sb);

	if (inode) {
	inode->i_ino = de->low_ino;
	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
	PROC_I(inode)->pde = de;

	if (is_empty_pde(de)) {
	make_empty_dir_inode(inode);
	return inode;
	}
	if (de->mode) {
	inode->i_mode = de->mode;
	inode->i_uid = de->uid;
	inode->i_gid = de->gid;
	}
	if (de->size)
	inode->i_size = de->size;
	if (de->nlink)
	set_nlink(inode, de->nlink);
	WARN_ON(!de->proc_iops);
	inode->i_op = de->proc_iops;
	if (de->proc_fops) {
	if (S_ISREG(inode->i_mode)) {
	#ifdef CONFIG_COMPAT
	if (!de->proc_fops->compat_ioctl)
	inode->i_fop =
	&proc_reg_file_ops_no_compat;
	else
	#endif
	inode->i_fop = &proc_reg_file_ops;
	} else {
	inode->i_fop = de->proc_fops;
	}
	}
	} else
	pde_put(de);
	return inode;
	}