[mirror_ubuntu-jammy-kernel.git] / fs / proc / inode.c

// 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;
	INIT_HLIST_NODE(&ei->sibling_inodes);
	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_ops->proc_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 proc_ops, proc_lseek) lseek;

		lseek = pde->proc_ops->proc_lseek;
		if (!lseek)
			lseek = default_llseek;
		rv = lseek(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 proc_ops, proc_read) read;

		read = pde->proc_ops->proc_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 proc_ops, proc_write) write;

		write = pde->proc_ops->proc_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 proc_ops, proc_poll) poll;

		poll = pde->proc_ops->proc_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 proc_ops, proc_ioctl) ioctl;

		ioctl = pde->proc_ops->proc_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 proc_ops, proc_compat_ioctl) compat_ioctl;

		compat_ioctl = pde->proc_ops->proc_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 proc_ops, proc_mmap) mmap;

		mmap = pde->proc_ops->proc_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 proc_ops, proc_get_unmapped_area) get_area;

		get_area = pde->proc_ops->proc_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 proc_ops, proc_open) open;
	typeof_member(struct proc_ops, proc_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_ops->proc_release;
	if (release) {
		pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
		if (!pdeo) {
			rv = -ENOMEM;
			goto out_unuse;
		}
	}

	open = pde->proc_ops->proc_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);

		if (S_ISREG(inode->i_mode)) {
			inode->i_op = de->proc_iops;
			inode->i_fop = &proc_reg_file_ops;
#ifdef CONFIG_COMPAT
			if (!de->proc_ops->proc_compat_ioctl) {
				inode->i_fop = &proc_reg_file_ops_no_compat;
			}
#endif
		} else if (S_ISDIR(inode->i_mode)) {
			inode->i_op = de->proc_iops;
			inode->i_fop = de->proc_dir_ops;
		} else if (S_ISLNK(inode->i_mode)) {
			inode->i_op = de->proc_iops;
			inode->i_fop = NULL;
		} else
			BUG();
	} else
	       pde_put(de);
	return inode;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/proc/inode.c
	4	*
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*/
	7
efb1a57d	8	#include <linux/cache.h>
1da177e4 LT	9	#include <linux/time.h>
	10	#include <linux/proc_fs.h>
	11	#include <linux/kernel.h>
97412950	12	#include <linux/pid_namespace.h>
1da177e4 LT	13	#include <linux/mm.h>
	14	#include <linux/string.h>
	15	#include <linux/stat.h>
786d7e16	16	#include <linux/completion.h>
dd23aae4	17	#include <linux/poll.h>
87ebdc00	18	#include <linux/printk.h>
1da177e4 LT	19	#include <linux/file.h>
	20	#include <linux/limits.h>
	21	#include <linux/init.h>
	22	#include <linux/module.h>
9043476f	23	#include <linux/sysctl.h>
97412950	24	#include <linux/seq_file.h>
5a0e3ad6	25	#include <linux/slab.h>
97412950	26	#include <linux/mount.h>
1da177e4	27
7c0f6ba6	28	#include <linux/uaccess.h>
1da177e4	29
fee781e6	30	#include "internal.h"
1da177e4	31
8267952b	32	static void proc_evict_inode(struct inode *inode)
1da177e4 LT	33	{
1da177e4 LT	34	struct proc_dir_entry *de;
dfef6dcd	35	struct ctl_table_header *head;
1da177e4	36
91b0abe3	37	truncate_inode_pages_final(&inode->i_data);
dbd5768f	38	clear_inode(inode);
fef26658	39
99f89551	40	/* Stop tracking associated processes */
13b41b09	41	put_pid(PROC_I(inode)->pid);
1da177e4 LT	42
1da177e4 LT	43	/* Let go of any associated proc directory entry */
6bee55f9	44	de = PDE(inode);
99b76233	45	if (de)
135d5655	46	pde_put(de);
d6cffbbe	47
dfef6dcd AV	48	head = PROC_I(inode)->sysctl;
dfef6dcd AV	49	if (head) {
1c44dbc8	50	RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL);
d6cffbbe	51	proc_sys_evict_inode(inode, head);
dfef6dcd	52	}
1da177e4 LT	53	}
1da177e4 LT	54
efb1a57d	55	static struct kmem_cache *proc_inode_cachep __ro_after_init;
195b8cf0	56	static struct kmem_cache *pde_opener_cache __ro_after_init;
1da177e4 LT	57
	58	static struct inode proc_alloc_inode(struct super_block sb)
	59	{
	60	struct proc_inode *ei;
1da177e4	61
f245e1c1	62	ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	63	if (!ei)
1da177e4 LT	64	return NULL;
13b41b09	65	ei->pid = NULL;
aed7a6c4	66	ei->fd = 0;
1da177e4 LT	67	ei->op.proc_get_link = NULL;
1da177e4 LT	68	ei->pde = NULL;
9043476f AV	69	ei->sysctl = NULL;
9043476f AV	70	ei->sysctl_entry = NULL;
0afa5ca8	71	INIT_HLIST_NODE(&ei->sibling_inodes);
3d3d35b1	72	ei->ns_ops = NULL;
230f72e9	73	return &ei->vfs_inode;
1da177e4 LT	74	}
1da177e4 LT	75
4aa6b55c	76	static void proc_free_inode(struct inode *inode)
1da177e4 LT	77	{
	78	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	79	}
	80
51cc5068	81	static void init_once(void *foo)
1da177e4 LT	82	{
	83	struct proc_inode ei = (struct proc_inode ) foo;
	84
a35afb83	85	inode_init_once(&ei->vfs_inode);
1da177e4	86	}
20c2df83	87
195b8cf0	88	void __init proc_init_kmemcache(void)
1da177e4 LT	89	{
	90	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	91	sizeof(struct proc_inode),
fffb60f9	92	0, (SLAB_RECLAIM_ACCOUNT\|
5d097056 VD	93	SLAB_MEM_SPREAD\|SLAB_ACCOUNT\|
5d097056 VD	94	SLAB_PANIC),
20c2df83	95	init_once);
195b8cf0 AD	96	pde_opener_cache =
195b8cf0 AD	97	kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
2acddbe8	98	SLAB_ACCOUNT\|SLAB_PANIC, NULL);
b4884f23	99	proc_dir_entry_cache = kmem_cache_create_usercopy(
2d6e4e82 AD	100	"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
	101	offsetof(struct proc_dir_entry, inline_name),
	102	SIZEOF_PDE_INLINE_NAME, NULL);
	103	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
1da177e4 LT	104	}
1da177e4 LT	105
97412950 VK	106	static int proc_show_options(struct seq_file seq, struct dentry root)
97412950 VK	107	{
0499680a VK	108	struct super_block *sb = root->d_sb;
	109	struct pid_namespace *pid = sb->s_fs_info;
	110
dcb0f222 EB	111	if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
dcb0f222 EB	112	seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
796f571b	113	if (pid->hide_pid != HIDEPID_OFF)
0499680a VK	114	seq_printf(seq, ",hidepid=%u", pid->hide_pid);
0499680a VK	115
97412950 VK	116	return 0;
	117	}
	118
60a3c3a5	119	const struct super_operations proc_sops = {
1da177e4	120	.alloc_inode = proc_alloc_inode,
4aa6b55c	121	.free_inode = proc_free_inode,
1da177e4	122	.drop_inode = generic_delete_inode,
8267952b	123	.evict_inode = proc_evict_inode,
1da177e4	124	.statfs = simple_statfs,
97412950	125	.show_options = proc_show_options,
1da177e4 LT	126	};
1da177e4 LT	127
866ad9a7 AV	128	enum {BIAS = -1U<<31};
	129
	130	static inline int use_pde(struct proc_dir_entry *pde)
	131	{
15b158b4	132	return likely(atomic_inc_unless_negative(&pde->in_use));
881adb85 AD	133	}
881adb85 AD	134
866ad9a7	135	static void unuse_pde(struct proc_dir_entry *pde)
881adb85	136	{
15b158b4	137	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
05c0ae21	138	complete(pde->pde_unload_completion);
786d7e16 AD	139	}
786d7e16 AD	140
2f897424	141	/* pde is locked on entry, unlocked on exit */
ca469f35 AV	142	static void close_pdeo(struct proc_dir_entry pde, struct pde_opener pdeo)
ca469f35 AV	143	{
492b2da6 AD	144	/*
	145	* close() (proc_reg_release()) can't delete an entry and proceed:
	146	* ->release hook needs to be available at the right moment.
	147	*
	148	* rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
	149	* "struct file" needs to be available at the right moment.
	150	*
	151	* Therefore, first process to enter this function does ->release() and
	152	* signals its completion to the other process which does nothing.
	153	*/
05c0ae21	154	if (pdeo->closing) {
ca469f35	155	/* somebody else is doing that, just wait */
05c0ae21 AV	156	DECLARE_COMPLETION_ONSTACK(c);
05c0ae21 AV	157	pdeo->c = &c;
ca469f35	158	spin_unlock(&pde->pde_unload_lock);
05c0ae21	159	wait_for_completion(&c);
ca469f35 AV	160	} else {
ca469f35 AV	161	struct file *file;
2f897424 AD	162	struct completion *c;
2f897424 AD	163
f5887c71	164	pdeo->closing = true;
ca469f35 AV	165	spin_unlock(&pde->pde_unload_lock);
ca469f35 AV	166	file = pdeo->file;
d56c0d45	167	pde->proc_ops->proc_release(file_inode(file), file);
ca469f35	168	spin_lock(&pde->pde_unload_lock);
492b2da6	169	/* After ->release. */
06a0c417	170	list_del(&pdeo->lh);
2f897424 AD	171	c = pdeo->c;
	172	spin_unlock(&pde->pde_unload_lock);
	173	if (unlikely(c))
	174	complete(c);
195b8cf0	175	kmem_cache_free(pde_opener_cache, pdeo);
05c0ae21	176	}
ca469f35 AV	177	}
ca469f35 AV	178
866ad9a7	179	void proc_entry_rundown(struct proc_dir_entry *de)
786d7e16	180	{
05c0ae21	181	DECLARE_COMPLETION_ONSTACK(c);
866ad9a7	182	/* Wait until all existing callers into module are done. */
05c0ae21 AV	183	de->pde_unload_completion = &c;
	184	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
	185	wait_for_completion(&c);
786d7e16	186
492b2da6 AD	187	/* ->pde_openers list can't grow from now on. */
492b2da6 AD	188
05c0ae21	189	spin_lock(&de->pde_unload_lock);
866ad9a7 AV	190	while (!list_empty(&de->pde_openers)) {
866ad9a7 AV	191	struct pde_opener *pdeo;
866ad9a7	192	pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
ca469f35	193	close_pdeo(de, pdeo);
2f897424	194	spin_lock(&de->pde_unload_lock);
866ad9a7 AV	195	}
866ad9a7 AV	196	spin_unlock(&de->pde_unload_lock);
786d7e16 AD	197	}
786d7e16 AD	198
866ad9a7 AV	199	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	200	{
	201	struct proc_dir_entry *pde = PDE(file_inode(file));
	202	loff_t rv = -EINVAL;
	203	if (use_pde(pde)) {
d56c0d45	204	typeof_member(struct proc_ops, proc_lseek) lseek;
9af27b28	205
d56c0d45 AD	206	lseek = pde->proc_ops->proc_lseek;
	207	if (!lseek)
	208	lseek = default_llseek;
	209	rv = lseek(file, offset, whence);
866ad9a7 AV	210	unuse_pde(pde);
866ad9a7 AV	211	}
786d7e16 AD	212	return rv;
	213	}
	214
866ad9a7	215	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
786d7e16	216	{
496ad9aa	217	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	218	ssize_t rv = -EIO;
866ad9a7	219	if (use_pde(pde)) {
d56c0d45	220	typeof_member(struct proc_ops, proc_read) read;
9af27b28	221
d56c0d45	222	read = pde->proc_ops->proc_read;
866ad9a7 AV	223	if (read)
	224	rv = read(file, buf, count, ppos);
	225	unuse_pde(pde);
786d7e16	226	}
866ad9a7 AV	227	return rv;
866ad9a7 AV	228	}
786d7e16	229
866ad9a7 AV	230	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
866ad9a7 AV	231	{
866ad9a7 AV	232	struct proc_dir_entry *pde = PDE(file_inode(file));
	233	ssize_t rv = -EIO;
	234	if (use_pde(pde)) {
d56c0d45	235	typeof_member(struct proc_ops, proc_write) write;
9af27b28	236
d56c0d45	237	write = pde->proc_ops->proc_write;
866ad9a7 AV	238	if (write)
	239	rv = write(file, buf, count, ppos);
	240	unuse_pde(pde);
	241	}
786d7e16 AD	242	return rv;
	243	}
	244
076ccb76	245	static __poll_t proc_reg_poll(struct file file, struct poll_table_struct pts)
786d7e16	246	{
496ad9aa	247	struct proc_dir_entry *pde = PDE(file_inode(file));
e6c8adca	248	__poll_t rv = DEFAULT_POLLMASK;
866ad9a7	249	if (use_pde(pde)) {
d56c0d45	250	typeof_member(struct proc_ops, proc_poll) poll;
9af27b28	251
d56c0d45	252	poll = pde->proc_ops->proc_poll;
866ad9a7 AV	253	if (poll)
	254	rv = poll(file, pts);
	255	unuse_pde(pde);
786d7e16	256	}
786d7e16 AD	257	return rv;
	258	}
	259
	260	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	261	{
496ad9aa	262	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	263	long rv = -ENOTTY;
866ad9a7	264	if (use_pde(pde)) {
d56c0d45	265	typeof_member(struct proc_ops, proc_ioctl) ioctl;
9af27b28	266
d56c0d45	267	ioctl = pde->proc_ops->proc_ioctl;
866ad9a7 AV	268	if (ioctl)
	269	rv = ioctl(file, cmd, arg);
	270	unuse_pde(pde);
786d7e16	271	}
786d7e16 AD	272	return rv;
	273	}
	274
	275	#ifdef CONFIG_COMPAT
	276	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	277	{
496ad9aa	278	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	279	long rv = -ENOTTY;
866ad9a7	280	if (use_pde(pde)) {
d56c0d45	281	typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
9af27b28	282
d56c0d45	283	compat_ioctl = pde->proc_ops->proc_compat_ioctl;
866ad9a7 AV	284	if (compat_ioctl)
	285	rv = compat_ioctl(file, cmd, arg);
	286	unuse_pde(pde);
786d7e16	287	}
786d7e16 AD	288	return rv;
	289	}
	290	#endif
	291
	292	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
	293	{
496ad9aa	294	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	295	int rv = -EIO;
866ad9a7	296	if (use_pde(pde)) {
d56c0d45	297	typeof_member(struct proc_ops, proc_mmap) mmap;
9af27b28	298
d56c0d45	299	mmap = pde->proc_ops->proc_mmap;
866ad9a7 AV	300	if (mmap)
	301	rv = mmap(file, vma);
	302	unuse_pde(pde);
786d7e16	303	}
786d7e16 AD	304	return rv;
	305	}
	306
5721cf84 HD	307	static unsigned long
	308	proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
	309	unsigned long len, unsigned long pgoff,
	310	unsigned long flags)
c4fe2448 AD	311	{
c4fe2448 AD	312	struct proc_dir_entry *pde = PDE(file_inode(file));
2cbe3b0a	313	unsigned long rv = -EIO;
ae5758a1	314
c4fe2448	315	if (use_pde(pde)) {
d56c0d45	316	typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
ae5758a1	317
d56c0d45	318	get_area = pde->proc_ops->proc_get_unmapped_area;
fad1a86e	319	#ifdef CONFIG_MMU
ae5758a1 JB	320	if (!get_area)
ae5758a1 JB	321	get_area = current->mm->get_unmapped_area;
fad1a86e	322	#endif
ae5758a1	323
5721cf84 HD	324	if (get_area)
5721cf84 HD	325	rv = get_area(file, orig_addr, len, pgoff, flags);
ae5758a1 JB	326	else
ae5758a1 JB	327	rv = orig_addr;
c4fe2448 AD	328	unuse_pde(pde);
	329	}
	330	return rv;
	331	}
	332
786d7e16 AD	333	static int proc_reg_open(struct inode inode, struct file file)
	334	{
	335	struct proc_dir_entry *pde = PDE(inode);
	336	int rv = 0;
d56c0d45 AD	337	typeof_member(struct proc_ops, proc_open) open;
d56c0d45 AD	338	typeof_member(struct proc_ops, proc_release) release;
881adb85 AD	339	struct pde_opener *pdeo;
	340
	341	/*
492b2da6 AD	342	* Ensure that
	343	* 1) PDE's ->release hook will be called no matter what
	344	* either normally by close()/->release, or forcefully by
	345	* rmmod/remove_proc_entry.
	346	*
	347	* 2) rmmod isn't blocked by opening file in /proc and sitting on
	348	* the descriptor (including "rmmod foo </proc/foo" scenario).
881adb85	349	*
492b2da6	350	* Save every "struct file" with custom ->release hook.
881adb85	351	*/
e7a6e291	352	if (!use_pde(pde))
d2857e79	353	return -ENOENT;
e7a6e291	354
d56c0d45	355	release = pde->proc_ops->proc_release;
e7a6e291	356	if (release) {
195b8cf0	357	pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
e7a6e291 AD	358	if (!pdeo) {
	359	rv = -ENOMEM;
	360	goto out_unuse;
	361	}
	362	}
786d7e16	363
d56c0d45	364	open = pde->proc_ops->proc_open;
786d7e16 AD	365	if (open)
	366	rv = open(inode, file);
	367
e7a6e291 AD	368	if (release) {
	369	if (rv == 0) {
	370	/* To know what to release. */
	371	pdeo->file = file;
	372	pdeo->closing = false;
	373	pdeo->c = NULL;
	374	spin_lock(&pde->pde_unload_lock);
	375	list_add(&pdeo->lh, &pde->pde_openers);
	376	spin_unlock(&pde->pde_unload_lock);
	377	} else
195b8cf0	378	kmem_cache_free(pde_opener_cache, pdeo);
e7a6e291	379	}
05c0ae21	380
e7a6e291	381	out_unuse:
05c0ae21	382	unuse_pde(pde);
786d7e16 AD	383	return rv;
	384	}
	385
	386	static int proc_reg_release(struct inode inode, struct file file)
	387	{
	388	struct proc_dir_entry *pde = PDE(inode);
881adb85	389	struct pde_opener *pdeo;
786d7e16	390	spin_lock(&pde->pde_unload_lock);
ca469f35 AV	391	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	392	if (pdeo->file == file) {
	393	close_pdeo(pde, pdeo);
2f897424	394	return 0;
ca469f35	395	}
881adb85	396	}
786d7e16	397	spin_unlock(&pde->pde_unload_lock);
ca469f35	398	return 0;
786d7e16 AD	399	}
	400
	401	static const struct file_operations proc_reg_file_ops = {
	402	.llseek = proc_reg_llseek,
	403	.read = proc_reg_read,
	404	.write = proc_reg_write,
	405	.poll = proc_reg_poll,
	406	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	407	#ifdef CONFIG_COMPAT
	408	.compat_ioctl = proc_reg_compat_ioctl,
	409	#endif
	410	.mmap = proc_reg_mmap,
c4fe2448	411	.get_unmapped_area = proc_reg_get_unmapped_area,
786d7e16 AD	412	.open = proc_reg_open,
	413	.release = proc_reg_release,
	414	};
	415
778f3dd5 DM	416	#ifdef CONFIG_COMPAT
	417	static const struct file_operations proc_reg_file_ops_no_compat = {
	418	.llseek = proc_reg_llseek,
	419	.read = proc_reg_read,
	420	.write = proc_reg_write,
	421	.poll = proc_reg_poll,
	422	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	423	.mmap = proc_reg_mmap,
c4fe2448	424	.get_unmapped_area = proc_reg_get_unmapped_area,
778f3dd5 DM	425	.open = proc_reg_open,
	426	.release = proc_reg_release,
	427	};
	428	#endif
	429
fceef393 AV	430	static void proc_put_link(void *p)
	431	{
	432	unuse_pde(p);
	433	}
	434
6b255391	435	static const char proc_get_link(struct dentry dentry,
fceef393 AV	436	struct inode *inode,
fceef393 AV	437	struct delayed_call *done)
7e0e953b	438	{
6b255391	439	struct proc_dir_entry *pde = PDE(inode);
15b158b4	440	if (!use_pde(pde))
7e0e953b	441	return ERR_PTR(-EINVAL);
fceef393	442	set_delayed_call(done, proc_put_link, pde);
680baacb	443	return pde->data;
7e0e953b AV	444	}
7e0e953b AV	445
7e0e953b	446	const struct inode_operations proc_link_inode_operations = {
6b255391	447	.get_link = proc_get_link,
7e0e953b AV	448	};
7e0e953b AV	449
6d1b6e4e	450	struct inode proc_get_inode(struct super_block sb, struct proc_dir_entry *de)
1da177e4	451	{
51f0885e	452	struct inode *inode = new_inode_pseudo(sb);
1da177e4	453
51f0885e LT	454	if (inode) {
51f0885e LT	455	inode->i_ino = de->low_ino;
078cd827	456	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
a1d4aebb	457	PROC_I(inode)->pde = de;
5e971dce	458
eb6d38d5 EB	459	if (is_empty_pde(de)) {
	460	make_empty_dir_inode(inode);
	461	return inode;
	462	}
5e971dce AD	463	if (de->mode) {
	464	inode->i_mode = de->mode;
	465	inode->i_uid = de->uid;
	466	inode->i_gid = de->gid;
	467	}
	468	if (de->size)
	469	inode->i_size = de->size;
	470	if (de->nlink)
bfe86848	471	set_nlink(inode, de->nlink);
d56c0d45 AD	472
	473	if (S_ISREG(inode->i_mode)) {
	474	inode->i_op = de->proc_iops;
	475	inode->i_fop = &proc_reg_file_ops;
778f3dd5	476	#ifdef CONFIG_COMPAT
d56c0d45 AD	477	if (!de->proc_ops->proc_compat_ioctl) {
d56c0d45 AD	478	inode->i_fop = &proc_reg_file_ops_no_compat;
778f3dd5	479	}
d56c0d45 AD	480	#endif
	481	} else if (S_ISDIR(inode->i_mode)) {
	482	inode->i_op = de->proc_iops;
	483	inode->i_fop = de->proc_dir_ops;
	484	} else if (S_ISLNK(inode->i_mode)) {
	485	inode->i_op = de->proc_iops;
	486	inode->i_fop = NULL;
	487	} else
	488	BUG();
99b76233	489	} else
135d5655	490	pde_put(de);
1da177e4	491	return inode;
d3d009cb	492	}