[linux-2.6-block.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;
	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;
}
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;
3d3d35b1	71	ei->ns_ops = NULL;
230f72e9	72	return &ei->vfs_inode;
1da177e4 LT	73	}
1da177e4 LT	74
4aa6b55c	75	static void proc_free_inode(struct inode *inode)
1da177e4 LT	76	{
	77	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	78	}
	79
51cc5068	80	static void init_once(void *foo)
1da177e4 LT	81	{
	82	struct proc_inode ei = (struct proc_inode ) foo;
	83
a35afb83	84	inode_init_once(&ei->vfs_inode);
1da177e4	85	}
20c2df83	86
195b8cf0	87	void __init proc_init_kmemcache(void)
1da177e4 LT	88	{
	89	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	90	sizeof(struct proc_inode),
fffb60f9	91	0, (SLAB_RECLAIM_ACCOUNT\|
5d097056 VD	92	SLAB_MEM_SPREAD\|SLAB_ACCOUNT\|
5d097056 VD	93	SLAB_PANIC),
20c2df83	94	init_once);
195b8cf0 AD	95	pde_opener_cache =
195b8cf0 AD	96	kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
2acddbe8	97	SLAB_ACCOUNT\|SLAB_PANIC, NULL);
b4884f23	98	proc_dir_entry_cache = kmem_cache_create_usercopy(
2d6e4e82 AD	99	"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
	100	offsetof(struct proc_dir_entry, inline_name),
	101	SIZEOF_PDE_INLINE_NAME, NULL);
	102	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
1da177e4 LT	103	}
1da177e4 LT	104
97412950 VK	105	static int proc_show_options(struct seq_file seq, struct dentry root)
97412950 VK	106	{
0499680a VK	107	struct super_block *sb = root->d_sb;
	108	struct pid_namespace *pid = sb->s_fs_info;
	109
dcb0f222 EB	110	if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
dcb0f222 EB	111	seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
796f571b	112	if (pid->hide_pid != HIDEPID_OFF)
0499680a VK	113	seq_printf(seq, ",hidepid=%u", pid->hide_pid);
0499680a VK	114
97412950 VK	115	return 0;
	116	}
	117
60a3c3a5	118	const struct super_operations proc_sops = {
1da177e4	119	.alloc_inode = proc_alloc_inode,
4aa6b55c	120	.free_inode = proc_free_inode,
1da177e4	121	.drop_inode = generic_delete_inode,
8267952b	122	.evict_inode = proc_evict_inode,
1da177e4	123	.statfs = simple_statfs,
97412950	124	.show_options = proc_show_options,
1da177e4 LT	125	};
1da177e4 LT	126
866ad9a7 AV	127	enum {BIAS = -1U<<31};
	128
	129	static inline int use_pde(struct proc_dir_entry *pde)
	130	{
15b158b4	131	return likely(atomic_inc_unless_negative(&pde->in_use));
881adb85 AD	132	}
881adb85 AD	133
866ad9a7	134	static void unuse_pde(struct proc_dir_entry *pde)
881adb85	135	{
15b158b4	136	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
05c0ae21	137	complete(pde->pde_unload_completion);
786d7e16 AD	138	}
786d7e16 AD	139
2f897424	140	/* pde is locked on entry, unlocked on exit */
ca469f35 AV	141	static void close_pdeo(struct proc_dir_entry pde, struct pde_opener pdeo)
ca469f35 AV	142	{
492b2da6 AD	143	/*
	144	* close() (proc_reg_release()) can't delete an entry and proceed:
	145	* ->release hook needs to be available at the right moment.
	146	*
	147	* rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
	148	* "struct file" needs to be available at the right moment.
	149	*
	150	* Therefore, first process to enter this function does ->release() and
	151	* signals its completion to the other process which does nothing.
	152	*/
05c0ae21	153	if (pdeo->closing) {
ca469f35	154	/* somebody else is doing that, just wait */
05c0ae21 AV	155	DECLARE_COMPLETION_ONSTACK(c);
05c0ae21 AV	156	pdeo->c = &c;
ca469f35	157	spin_unlock(&pde->pde_unload_lock);
05c0ae21	158	wait_for_completion(&c);
ca469f35 AV	159	} else {
ca469f35 AV	160	struct file *file;
2f897424 AD	161	struct completion *c;
2f897424 AD	162
f5887c71	163	pdeo->closing = true;
ca469f35 AV	164	spin_unlock(&pde->pde_unload_lock);
	165	file = pdeo->file;
	166	pde->proc_fops->release(file_inode(file), file);
	167	spin_lock(&pde->pde_unload_lock);
492b2da6	168	/* After ->release. */
06a0c417	169	list_del(&pdeo->lh);
2f897424 AD	170	c = pdeo->c;
	171	spin_unlock(&pde->pde_unload_lock);
	172	if (unlikely(c))
	173	complete(c);
195b8cf0	174	kmem_cache_free(pde_opener_cache, pdeo);
05c0ae21	175	}
ca469f35 AV	176	}
ca469f35 AV	177
866ad9a7	178	void proc_entry_rundown(struct proc_dir_entry *de)
786d7e16	179	{
05c0ae21	180	DECLARE_COMPLETION_ONSTACK(c);
866ad9a7	181	/* Wait until all existing callers into module are done. */
05c0ae21 AV	182	de->pde_unload_completion = &c;
	183	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
	184	wait_for_completion(&c);
786d7e16	185
492b2da6 AD	186	/* ->pde_openers list can't grow from now on. */
492b2da6 AD	187
05c0ae21	188	spin_lock(&de->pde_unload_lock);
866ad9a7 AV	189	while (!list_empty(&de->pde_openers)) {
866ad9a7 AV	190	struct pde_opener *pdeo;
866ad9a7	191	pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
ca469f35	192	close_pdeo(de, pdeo);
2f897424	193	spin_lock(&de->pde_unload_lock);
866ad9a7 AV	194	}
866ad9a7 AV	195	spin_unlock(&de->pde_unload_lock);
786d7e16 AD	196	}
786d7e16 AD	197
866ad9a7 AV	198	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	199	{
	200	struct proc_dir_entry *pde = PDE(file_inode(file));
	201	loff_t rv = -EINVAL;
	202	if (use_pde(pde)) {
9af27b28 AD	203	typeof_member(struct file_operations, llseek) llseek;
9af27b28 AD	204
866ad9a7 AV	205	llseek = pde->proc_fops->llseek;
	206	if (!llseek)
	207	llseek = default_llseek;
	208	rv = llseek(file, offset, whence);
	209	unuse_pde(pde);
	210	}
786d7e16 AD	211	return rv;
	212	}
	213
866ad9a7	214	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
786d7e16	215	{
496ad9aa	216	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	217	ssize_t rv = -EIO;
866ad9a7	218	if (use_pde(pde)) {
9af27b28 AD	219	typeof_member(struct file_operations, read) read;
9af27b28 AD	220
866ad9a7 AV	221	read = pde->proc_fops->read;
	222	if (read)
	223	rv = read(file, buf, count, ppos);
	224	unuse_pde(pde);
786d7e16	225	}
866ad9a7 AV	226	return rv;
866ad9a7 AV	227	}
786d7e16	228
866ad9a7 AV	229	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
866ad9a7 AV	230	{
866ad9a7 AV	231	struct proc_dir_entry *pde = PDE(file_inode(file));
	232	ssize_t rv = -EIO;
	233	if (use_pde(pde)) {
9af27b28 AD	234	typeof_member(struct file_operations, write) write;
9af27b28 AD	235
866ad9a7 AV	236	write = pde->proc_fops->write;
	237	if (write)
	238	rv = write(file, buf, count, ppos);
	239	unuse_pde(pde);
	240	}
786d7e16 AD	241	return rv;
	242	}
	243
076ccb76	244	static __poll_t proc_reg_poll(struct file file, struct poll_table_struct pts)
786d7e16	245	{
496ad9aa	246	struct proc_dir_entry *pde = PDE(file_inode(file));
e6c8adca	247	__poll_t rv = DEFAULT_POLLMASK;
866ad9a7	248	if (use_pde(pde)) {
9af27b28 AD	249	typeof_member(struct file_operations, poll) poll;
9af27b28 AD	250
866ad9a7 AV	251	poll = pde->proc_fops->poll;
	252	if (poll)
	253	rv = poll(file, pts);
	254	unuse_pde(pde);
786d7e16	255	}
786d7e16 AD	256	return rv;
	257	}
	258
	259	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	260	{
496ad9aa	261	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	262	long rv = -ENOTTY;
866ad9a7	263	if (use_pde(pde)) {
9af27b28 AD	264	typeof_member(struct file_operations, unlocked_ioctl) ioctl;
9af27b28 AD	265
866ad9a7 AV	266	ioctl = pde->proc_fops->unlocked_ioctl;
	267	if (ioctl)
	268	rv = ioctl(file, cmd, arg);
	269	unuse_pde(pde);
786d7e16	270	}
786d7e16 AD	271	return rv;
	272	}
	273
	274	#ifdef CONFIG_COMPAT
	275	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	276	{
496ad9aa	277	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	278	long rv = -ENOTTY;
866ad9a7	279	if (use_pde(pde)) {
9af27b28 AD	280	typeof_member(struct file_operations, compat_ioctl) compat_ioctl;
9af27b28 AD	281
866ad9a7 AV	282	compat_ioctl = pde->proc_fops->compat_ioctl;
	283	if (compat_ioctl)
	284	rv = compat_ioctl(file, cmd, arg);
	285	unuse_pde(pde);
786d7e16	286	}
786d7e16 AD	287	return rv;
	288	}
	289	#endif
	290
	291	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
	292	{
496ad9aa	293	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	294	int rv = -EIO;
866ad9a7	295	if (use_pde(pde)) {
9af27b28 AD	296	typeof_member(struct file_operations, mmap) mmap;
9af27b28 AD	297
866ad9a7 AV	298	mmap = pde->proc_fops->mmap;
	299	if (mmap)
	300	rv = mmap(file, vma);
	301	unuse_pde(pde);
786d7e16	302	}
786d7e16 AD	303	return rv;
	304	}
	305
5721cf84 HD	306	static unsigned long
	307	proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
	308	unsigned long len, unsigned long pgoff,
	309	unsigned long flags)
c4fe2448 AD	310	{
c4fe2448 AD	311	struct proc_dir_entry *pde = PDE(file_inode(file));
2cbe3b0a	312	unsigned long rv = -EIO;
ae5758a1	313
c4fe2448	314	if (use_pde(pde)) {
9af27b28	315	typeof_member(struct file_operations, get_unmapped_area) get_area;
ae5758a1 JB	316
ae5758a1 JB	317	get_area = pde->proc_fops->get_unmapped_area;
fad1a86e	318	#ifdef CONFIG_MMU
ae5758a1 JB	319	if (!get_area)
ae5758a1 JB	320	get_area = current->mm->get_unmapped_area;
fad1a86e	321	#endif
ae5758a1	322
5721cf84 HD	323	if (get_area)
5721cf84 HD	324	rv = get_area(file, orig_addr, len, pgoff, flags);
ae5758a1 JB	325	else
ae5758a1 JB	326	rv = orig_addr;
c4fe2448 AD	327	unuse_pde(pde);
	328	}
	329	return rv;
	330	}
	331
786d7e16 AD	332	static int proc_reg_open(struct inode inode, struct file file)
	333	{
	334	struct proc_dir_entry *pde = PDE(inode);
	335	int rv = 0;
9af27b28 AD	336	typeof_member(struct file_operations, open) open;
9af27b28 AD	337	typeof_member(struct file_operations, release) release;
881adb85 AD	338	struct pde_opener *pdeo;
	339
	340	/*
492b2da6 AD	341	* Ensure that
	342	* 1) PDE's ->release hook will be called no matter what
	343	* either normally by close()/->release, or forcefully by
	344	* rmmod/remove_proc_entry.
	345	*
	346	* 2) rmmod isn't blocked by opening file in /proc and sitting on
	347	* the descriptor (including "rmmod foo </proc/foo" scenario).
881adb85	348	*
492b2da6	349	* Save every "struct file" with custom ->release hook.
881adb85	350	*/
e7a6e291	351	if (!use_pde(pde))
d2857e79	352	return -ENOENT;
e7a6e291	353
881adb85	354	release = pde->proc_fops->release;
e7a6e291	355	if (release) {
195b8cf0	356	pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
e7a6e291 AD	357	if (!pdeo) {
	358	rv = -ENOMEM;
	359	goto out_unuse;
	360	}
	361	}
786d7e16	362
e7a6e291	363	open = pde->proc_fops->open;
786d7e16 AD	364	if (open)
	365	rv = open(inode, file);
	366
e7a6e291 AD	367	if (release) {
	368	if (rv == 0) {
	369	/* To know what to release. */
	370	pdeo->file = file;
	371	pdeo->closing = false;
	372	pdeo->c = NULL;
	373	spin_lock(&pde->pde_unload_lock);
	374	list_add(&pdeo->lh, &pde->pde_openers);
	375	spin_unlock(&pde->pde_unload_lock);
	376	} else
195b8cf0	377	kmem_cache_free(pde_opener_cache, pdeo);
e7a6e291	378	}
05c0ae21	379
e7a6e291	380	out_unuse:
05c0ae21	381	unuse_pde(pde);
786d7e16 AD	382	return rv;
	383	}
	384
	385	static int proc_reg_release(struct inode inode, struct file file)
	386	{
	387	struct proc_dir_entry *pde = PDE(inode);
881adb85	388	struct pde_opener *pdeo;
786d7e16	389	spin_lock(&pde->pde_unload_lock);
ca469f35 AV	390	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	391	if (pdeo->file == file) {
	392	close_pdeo(pde, pdeo);
2f897424	393	return 0;
ca469f35	394	}
881adb85	395	}
786d7e16	396	spin_unlock(&pde->pde_unload_lock);
ca469f35	397	return 0;
786d7e16 AD	398	}
	399
	400	static const struct file_operations proc_reg_file_ops = {
	401	.llseek = proc_reg_llseek,
	402	.read = proc_reg_read,
	403	.write = proc_reg_write,
	404	.poll = proc_reg_poll,
	405	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	406	#ifdef CONFIG_COMPAT
	407	.compat_ioctl = proc_reg_compat_ioctl,
	408	#endif
	409	.mmap = proc_reg_mmap,
c4fe2448	410	.get_unmapped_area = proc_reg_get_unmapped_area,
786d7e16 AD	411	.open = proc_reg_open,
	412	.release = proc_reg_release,
	413	};
	414
778f3dd5 DM	415	#ifdef CONFIG_COMPAT
	416	static const struct file_operations proc_reg_file_ops_no_compat = {
	417	.llseek = proc_reg_llseek,
	418	.read = proc_reg_read,
	419	.write = proc_reg_write,
	420	.poll = proc_reg_poll,
	421	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	422	.mmap = proc_reg_mmap,
c4fe2448	423	.get_unmapped_area = proc_reg_get_unmapped_area,
778f3dd5 DM	424	.open = proc_reg_open,
	425	.release = proc_reg_release,
	426	};
	427	#endif
	428
fceef393 AV	429	static void proc_put_link(void *p)
	430	{
	431	unuse_pde(p);
	432	}
	433
6b255391	434	static const char proc_get_link(struct dentry dentry,
fceef393 AV	435	struct inode *inode,
fceef393 AV	436	struct delayed_call *done)
7e0e953b	437	{
6b255391	438	struct proc_dir_entry *pde = PDE(inode);
15b158b4	439	if (!use_pde(pde))
7e0e953b	440	return ERR_PTR(-EINVAL);
fceef393	441	set_delayed_call(done, proc_put_link, pde);
680baacb	442	return pde->data;
7e0e953b AV	443	}
7e0e953b AV	444
7e0e953b	445	const struct inode_operations proc_link_inode_operations = {
6b255391	446	.get_link = proc_get_link,
7e0e953b AV	447	};
7e0e953b AV	448
6d1b6e4e	449	struct inode proc_get_inode(struct super_block sb, struct proc_dir_entry *de)
1da177e4	450	{
51f0885e	451	struct inode *inode = new_inode_pseudo(sb);
1da177e4	452
51f0885e LT	453	if (inode) {
51f0885e LT	454	inode->i_ino = de->low_ino;
078cd827	455	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
a1d4aebb	456	PROC_I(inode)->pde = de;
5e971dce	457
eb6d38d5 EB	458	if (is_empty_pde(de)) {
	459	make_empty_dir_inode(inode);
	460	return inode;
	461	}
5e971dce AD	462	if (de->mode) {
	463	inode->i_mode = de->mode;
	464	inode->i_uid = de->uid;
	465	inode->i_gid = de->gid;
	466	}
	467	if (de->size)
	468	inode->i_size = de->size;
	469	if (de->nlink)
bfe86848	470	set_nlink(inode, de->nlink);
b6cdc731 AV	471	WARN_ON(!de->proc_iops);
b6cdc731 AV	472	inode->i_op = de->proc_iops;
5e971dce AD	473	if (de->proc_fops) {
5e971dce AD	474	if (S_ISREG(inode->i_mode)) {
778f3dd5	475	#ifdef CONFIG_COMPAT
5e971dce AD	476	if (!de->proc_fops->compat_ioctl)
	477	inode->i_fop =
	478	&proc_reg_file_ops_no_compat;
	479	else
778f3dd5	480	#endif
5e971dce AD	481	inode->i_fop = &proc_reg_file_ops;
	482	} else {
	483	inode->i_fop = de->proc_fops;
778f3dd5	484	}
786d7e16	485	}
99b76233	486	} else
135d5655	487	pde_put(de);
1da177e4	488	return inode;
d3d009cb	489	}