[linux-2.6-block.git] / fs / proc / inode.c

/*
 *  linux/fs/proc/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/completion.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/limits.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/sysctl.h>

#include <asm/system.h>
#include <asm/uaccess.h>

#include "internal.h"

static void proc_delete_inode(struct inode *inode)
{
	struct proc_dir_entry *de;

	truncate_inode_pages(&inode->i_data, 0);

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

	/* Let go of any associated proc directory entry */
	de = PROC_I(inode)->pde;
	if (de)
		pde_put(de);
	if (PROC_I(inode)->sysctl)
		sysctl_head_put(PROC_I(inode)->sysctl);
	clear_inode(inode);
}

struct vfsmount *proc_mnt;

static struct kmem_cache * proc_inode_cachep;

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

	ei = (struct proc_inode *)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;
	inode = &ei->vfs_inode;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	return inode;
}

static void proc_destroy_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_inodecache(void)
{
	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
					     sizeof(struct proc_inode),
					     0, (SLAB_RECLAIM_ACCOUNT|
						SLAB_MEM_SPREAD|SLAB_PANIC),
					     init_once);
}

static const struct super_operations proc_sops = {
	.alloc_inode	= proc_alloc_inode,
	.destroy_inode	= proc_destroy_inode,
	.drop_inode	= generic_delete_inode,
	.delete_inode	= proc_delete_inode,
	.statfs		= simple_statfs,
};

static void __pde_users_dec(struct proc_dir_entry *pde)
{
	pde->pde_users--;
	if (pde->pde_unload_completion && pde->pde_users == 0)
		complete(pde->pde_unload_completion);
}

void pde_users_dec(struct proc_dir_entry *pde)
{
	spin_lock(&pde->pde_unload_lock);
	__pde_users_dec(pde);
	spin_unlock(&pde->pde_unload_lock);
}

static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	loff_t rv = -EINVAL;
	loff_t (*llseek)(struct file *, loff_t, int);

	spin_lock(&pde->pde_unload_lock);
	/*
	 * remove_proc_entry() is going to delete PDE (as part of module
	 * cleanup sequence). No new callers into module allowed.
	 */
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	/*
	 * Bump refcount so that remove_proc_entry will wail for ->llseek to
	 * complete.
	 */
	pde->pde_users++;
	/*
	 * Save function pointer under lock, to protect against ->proc_fops
	 * NULL'ifying right after ->pde_unload_lock is dropped.
	 */
	llseek = pde->proc_fops->llseek;
	spin_unlock(&pde->pde_unload_lock);

	if (!llseek)
		llseek = default_llseek;
	rv = llseek(file, offset, whence);

	pde_users_dec(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->f_path.dentry->d_inode);
	ssize_t rv = -EIO;
	ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	read = pde->proc_fops->read;
	spin_unlock(&pde->pde_unload_lock);

	if (read)
		rv = read(file, buf, count, ppos);

	pde_users_dec(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->f_path.dentry->d_inode);
	ssize_t rv = -EIO;
	ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	write = pde->proc_fops->write;
	spin_unlock(&pde->pde_unload_lock);

	if (write)
		rv = write(file, buf, count, ppos);

	pde_users_dec(pde);
	return rv;
}

static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	unsigned int rv = DEFAULT_POLLMASK;
	unsigned int (*poll)(struct file *, struct poll_table_struct *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	poll = pde->proc_fops->poll;
	spin_unlock(&pde->pde_unload_lock);

	if (poll)
		rv = poll(file, pts);

	pde_users_dec(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->f_path.dentry->d_inode);
	long rv = -ENOTTY;
	long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long);
	int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
	ioctl = pde->proc_fops->ioctl;
	spin_unlock(&pde->pde_unload_lock);

	if (unlocked_ioctl) {
		rv = unlocked_ioctl(file, cmd, arg);
		if (rv == -ENOIOCTLCMD)
			rv = -EINVAL;
	} else if (ioctl) {
		lock_kernel();
		rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
		unlock_kernel();
	}

	pde_users_dec(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->f_path.dentry->d_inode);
	long rv = -ENOTTY;
	long (*compat_ioctl)(struct file *, unsigned int, unsigned long);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	compat_ioctl = pde->proc_fops->compat_ioctl;
	spin_unlock(&pde->pde_unload_lock);

	if (compat_ioctl)
		rv = compat_ioctl(file, cmd, arg);

	pde_users_dec(pde);
	return rv;
}
#endif

static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	int rv = -EIO;
	int (*mmap)(struct file *, struct vm_area_struct *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	mmap = pde->proc_fops->mmap;
	spin_unlock(&pde->pde_unload_lock);

	if (mmap)
		rv = mmap(file, vma);

	pde_users_dec(pde);
	return rv;
}

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

	/*
	 * What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	 * sequence. ->release won't be called because ->proc_fops will be
	 * cleared. Depending on complexity of ->release, consequences vary.
	 *
	 * We can't wait for mercy when close will be done for real, it's
	 * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	 * by hand in remove_proc_entry(). For this, save opener's credentials
	 * for later.
	 */
	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	if (!pdeo)
		return -ENOMEM;

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
		spin_unlock(&pde->pde_unload_lock);
		kfree(pdeo);
		return -EINVAL;
	}
	pde->pde_users++;
	open = pde->proc_fops->open;
	release = pde->proc_fops->release;
	spin_unlock(&pde->pde_unload_lock);

	if (open)
		rv = open(inode, file);

	spin_lock(&pde->pde_unload_lock);
	if (rv == 0 && release) {
		/* To know what to release. */
		pdeo->inode = inode;
		pdeo->file = file;
		/* Strictly for "too late" ->release in proc_reg_release(). */
		pdeo->release = release;
		list_add(&pdeo->lh, &pde->pde_openers);
	} else
		kfree(pdeo);
	__pde_users_dec(pde);
	spin_unlock(&pde->pde_unload_lock);
	return rv;
}

static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde,
					struct inode *inode, struct file *file)
{
	struct pde_opener *pdeo;

	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
		if (pdeo->inode == inode && pdeo->file == file)
			return pdeo;
	}
	return NULL;
}

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

	spin_lock(&pde->pde_unload_lock);
	pdeo = find_pde_opener(pde, inode, file);
	if (!pde->proc_fops) {
		/*
		 * Can't simply exit, __fput() will think that everything is OK,
		 * and move on to freeing struct file. remove_proc_entry() will
		 * find slacker in opener's list and will try to do non-trivial
		 * things with struct file. Therefore, remove opener from list.
		 *
		 * But if opener is removed from list, who will ->release it?
		 */
		if (pdeo) {
			list_del(&pdeo->lh);
			spin_unlock(&pde->pde_unload_lock);
			rv = pdeo->release(inode, file);
			kfree(pdeo);
		} else
			spin_unlock(&pde->pde_unload_lock);
		return rv;
	}
	pde->pde_users++;
	release = pde->proc_fops->release;
	if (pdeo) {
		list_del(&pdeo->lh);
		kfree(pdeo);
	}
	spin_unlock(&pde->pde_unload_lock);

	if (release)
		rv = release(inode, file);

	pde_users_dec(pde);
	return rv;
}

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,
	.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,
	.open		= proc_reg_open,
	.release	= proc_reg_release,
};
#endif

struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
				struct proc_dir_entry *de)
{
	struct inode * inode;

	inode = iget_locked(sb, ino);
	if (!inode)
		return NULL;
	if (inode->i_state & I_NEW) {
		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
		PROC_I(inode)->fd = 0;
		PROC_I(inode)->pde = de;

		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)
			inode->i_nlink = de->nlink;
		if (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;
			}
		}
		unlock_new_inode(inode);
	} else
	       pde_put(de);
	return inode;
}			

int proc_fill_super(struct super_block *s)
{
	struct inode * root_inode;

	s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = PROC_SUPER_MAGIC;
	s->s_op = &proc_sops;
	s->s_time_gran = 1;
	
	pde_get(&proc_root);
	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
	if (!root_inode)
		goto out_no_root;
	root_inode->i_uid = 0;
	root_inode->i_gid = 0;
	s->s_root = d_alloc_root(root_inode);
	if (!s->s_root)
		goto out_no_root;
	return 0;

out_no_root:
	printk("proc_read_super: get root inode failed\n");
	iput(root_inode);
	pde_put(&proc_root);
	return -ENOMEM;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/proc/inode.c
	3	*
	4	* Copyright (C) 1991, 1992 Linus Torvalds
	5	*/
	6
	7	#include <linux/time.h>
	8	#include <linux/proc_fs.h>
	9	#include <linux/kernel.h>
	10	#include <linux/mm.h>
	11	#include <linux/string.h>
	12	#include <linux/stat.h>
786d7e16	13	#include <linux/completion.h>
dd23aae4	14	#include <linux/poll.h>
1da177e4 LT	15	#include <linux/file.h>
	16	#include <linux/limits.h>
	17	#include <linux/init.h>
	18	#include <linux/module.h>
	19	#include <linux/smp_lock.h>
9043476f	20	#include <linux/sysctl.h>
1da177e4 LT	21
	22	#include <asm/system.h>
	23	#include <asm/uaccess.h>
	24
fee781e6	25	#include "internal.h"
1da177e4	26
1da177e4 LT	27	static void proc_delete_inode(struct inode *inode)
	28	{
	29	struct proc_dir_entry *de;
1da177e4	30
fef26658 MF	31	truncate_inode_pages(&inode->i_data, 0);
fef26658 MF	32
99f89551	33	/* Stop tracking associated processes */
13b41b09	34	put_pid(PROC_I(inode)->pid);
1da177e4 LT	35
	36	/* Let go of any associated proc directory entry */
	37	de = PROC_I(inode)->pde;
99b76233	38	if (de)
135d5655	39	pde_put(de);
9043476f AV	40	if (PROC_I(inode)->sysctl)
9043476f AV	41	sysctl_head_put(PROC_I(inode)->sysctl);
1da177e4 LT	42	clear_inode(inode);
	43	}
	44
	45	struct vfsmount *proc_mnt;
	46
e18b890b	47	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	48
	49	static struct inode proc_alloc_inode(struct super_block sb)
	50	{
	51	struct proc_inode *ei;
	52	struct inode *inode;
	53
e94b1766	54	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	55	if (!ei)
1da177e4 LT	56	return NULL;
13b41b09	57	ei->pid = NULL;
aed7a6c4	58	ei->fd = 0;
1da177e4 LT	59	ei->op.proc_get_link = NULL;
1da177e4 LT	60	ei->pde = NULL;
9043476f AV	61	ei->sysctl = NULL;
9043476f AV	62	ei->sysctl_entry = NULL;
1da177e4 LT	63	inode = &ei->vfs_inode;
	64	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	65	return inode;
	66	}
	67
	68	static void proc_destroy_inode(struct inode *inode)
	69	{
	70	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	71	}
	72
51cc5068	73	static void init_once(void *foo)
1da177e4 LT	74	{
	75	struct proc_inode ei = (struct proc_inode ) foo;
	76
a35afb83	77	inode_init_once(&ei->vfs_inode);
1da177e4	78	}
20c2df83	79
5bcd7ff9	80	void __init proc_init_inodecache(void)
1da177e4 LT	81	{
	82	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	83	sizeof(struct proc_inode),
fffb60f9	84	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	85	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	86	init_once);
1da177e4 LT	87	}
1da177e4 LT	88
ee9b6d61	89	static const struct super_operations proc_sops = {
1da177e4 LT	90	.alloc_inode = proc_alloc_inode,
1da177e4 LT	91	.destroy_inode = proc_destroy_inode,
1da177e4 LT	92	.drop_inode = generic_delete_inode,
	93	.delete_inode = proc_delete_inode,
	94	.statfs = simple_statfs,
1da177e4 LT	95	};
1da177e4 LT	96
881adb85	97	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	98	{
786d7e16 AD	99	pde->pde_users--;
	100	if (pde->pde_unload_completion && pde->pde_users == 0)
	101	complete(pde->pde_unload_completion);
881adb85 AD	102	}
881adb85 AD	103
3dec7f59	104	void pde_users_dec(struct proc_dir_entry *pde)
881adb85 AD	105	{
	106	spin_lock(&pde->pde_unload_lock);
	107	__pde_users_dec(pde);
786d7e16 AD	108	spin_unlock(&pde->pde_unload_lock);
	109	}
	110
	111	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	112	{
	113	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	114	loff_t rv = -EINVAL;
	115	loff_t (llseek)(struct file , loff_t, int);
	116
	117	spin_lock(&pde->pde_unload_lock);
	118	/*
	119	* remove_proc_entry() is going to delete PDE (as part of module
	120	* cleanup sequence). No new callers into module allowed.
	121	*/
	122	if (!pde->proc_fops) {
	123	spin_unlock(&pde->pde_unload_lock);
	124	return rv;
	125	}
	126	/*
	127	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	128	* complete.
	129	*/
	130	pde->pde_users++;
	131	/*
	132	* Save function pointer under lock, to protect against ->proc_fops
	133	* NULL'ifying right after ->pde_unload_lock is dropped.
	134	*/
	135	llseek = pde->proc_fops->llseek;
	136	spin_unlock(&pde->pde_unload_lock);
	137
	138	if (!llseek)
	139	llseek = default_llseek;
	140	rv = llseek(file, offset, whence);
	141
	142	pde_users_dec(pde);
	143	return rv;
	144	}
	145
	146	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	147	{
	148	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	149	ssize_t rv = -EIO;
	150	ssize_t (read)(struct file , char __user , size_t, loff_t );
	151
	152	spin_lock(&pde->pde_unload_lock);
	153	if (!pde->proc_fops) {
	154	spin_unlock(&pde->pde_unload_lock);
	155	return rv;
	156	}
	157	pde->pde_users++;
	158	read = pde->proc_fops->read;
	159	spin_unlock(&pde->pde_unload_lock);
	160
	161	if (read)
	162	rv = read(file, buf, count, ppos);
	163
	164	pde_users_dec(pde);
	165	return rv;
	166	}
	167
	168	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	169	{
	170	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	171	ssize_t rv = -EIO;
172	ssize_t (write)(struct file , const char __user , size_t, loff_t );
173
174	spin_lock(&pde->pde_unload_lock);
175	if (!pde->proc_fops) {
176	spin_unlock(&pde->pde_unload_lock);
177	return rv;
178	}
179	pde->pde_users++;
180	write = pde->proc_fops->write;
181	spin_unlock(&pde->pde_unload_lock);
182
183	if (write)
184	rv = write(file, buf, count, ppos);
185
186	pde_users_dec(pde);
187	return rv;
188	}
189
190	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
191	{
192	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
dd23aae4	193	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	194	unsigned int (poll)(struct file , struct poll_table_struct *);
	195
	196	spin_lock(&pde->pde_unload_lock);
	197	if (!pde->proc_fops) {
	198	spin_unlock(&pde->pde_unload_lock);
	199	return rv;
	200	}
	201	pde->pde_users++;
	202	poll = pde->proc_fops->poll;
	203	spin_unlock(&pde->pde_unload_lock);
	204
	205	if (poll)
	206	rv = poll(file, pts);
	207
	208	pde_users_dec(pde);
	209	return rv;
	210	}
	211
	212	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	213	{
	214	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	215	long rv = -ENOTTY;
	216	long (unlocked_ioctl)(struct file , unsigned int, unsigned long);
	217	int (ioctl)(struct inode , struct file *, unsigned int, unsigned long);
	218
	219	spin_lock(&pde->pde_unload_lock);
	220	if (!pde->proc_fops) {
	221	spin_unlock(&pde->pde_unload_lock);
	222	return rv;
	223	}
	224	pde->pde_users++;
	225	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
	226	ioctl = pde->proc_fops->ioctl;
	227	spin_unlock(&pde->pde_unload_lock);
	228
	229	if (unlocked_ioctl) {
	230	rv = unlocked_ioctl(file, cmd, arg);
	231	if (rv == -ENOIOCTLCMD)
	232	rv = -EINVAL;
	233	} else if (ioctl) {
	234	lock_kernel();
	235	rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
	236	unlock_kernel();
	237	}
	238
	239	pde_users_dec(pde);
	240	return rv;
	241	}
	242
	243	#ifdef CONFIG_COMPAT
	244	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	245	{
	246	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	247	long rv = -ENOTTY;
	248	long (compat_ioctl)(struct file , unsigned int, unsigned long);
	249
	250	spin_lock(&pde->pde_unload_lock);
	251	if (!pde->proc_fops) {
	252	spin_unlock(&pde->pde_unload_lock);
	253	return rv;
	254	}
	255	pde->pde_users++;
	256	compat_ioctl = pde->proc_fops->compat_ioctl;
	257	spin_unlock(&pde->pde_unload_lock);
258
259	if (compat_ioctl)
260	rv = compat_ioctl(file, cmd, arg);
261
262	pde_users_dec(pde);
263	return rv;
264	}
265	#endif
266
267	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
268	{
269	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
270	int rv = -EIO;
271	int (mmap)(struct file , struct vm_area_struct *);
272
273	spin_lock(&pde->pde_unload_lock);
274	if (!pde->proc_fops) {
275	spin_unlock(&pde->pde_unload_lock);
276	return rv;
277	}
278	pde->pde_users++;
279	mmap = pde->proc_fops->mmap;
280	spin_unlock(&pde->pde_unload_lock);
281
282	if (mmap)
283	rv = mmap(file, vma);
284
285	pde_users_dec(pde);
286	return rv;
287	}
288
289	static int proc_reg_open(struct inode inode, struct file file)
290	{
291	struct proc_dir_entry *pde = PDE(inode);
292	int rv = 0;
293	int (open)(struct inode , struct file *);
881adb85 AD	294	int (release)(struct inode , struct file *);
	295	struct pde_opener *pdeo;
	296
	297	/*
	298	* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	299	* sequence. ->release won't be called because ->proc_fops will be
	300	* cleared. Depending on complexity of ->release, consequences vary.
	301	*
	302	* We can't wait for mercy when close will be done for real, it's
	303	* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	304	* by hand in remove_proc_entry(). For this, save opener's credentials
	305	* for later.
	306	*/
	307	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	308	if (!pdeo)
	309	return -ENOMEM;
786d7e16 AD	310
	311	spin_lock(&pde->pde_unload_lock);
	312	if (!pde->proc_fops) {
	313	spin_unlock(&pde->pde_unload_lock);
881adb85	314	kfree(pdeo);
300b994b	315	return -EINVAL;
786d7e16 AD	316	}
	317	pde->pde_users++;
	318	open = pde->proc_fops->open;
881adb85	319	release = pde->proc_fops->release;
786d7e16 AD	320	spin_unlock(&pde->pde_unload_lock);
	321
	322	if (open)
	323	rv = open(inode, file);
	324
881adb85 AD	325	spin_lock(&pde->pde_unload_lock);
	326	if (rv == 0 && release) {
	327	/* To know what to release. */
	328	pdeo->inode = inode;
	329	pdeo->file = file;
	330	/* Strictly for "too late" ->release in proc_reg_release(). */
	331	pdeo->release = release;
	332	list_add(&pdeo->lh, &pde->pde_openers);
	333	} else
	334	kfree(pdeo);
	335	__pde_users_dec(pde);
	336	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	337	return rv;
	338	}
	339
881adb85 AD	340	static struct pde_opener find_pde_opener(struct proc_dir_entry pde,
	341	struct inode inode, struct file file)
	342	{
	343	struct pde_opener *pdeo;
	344
	345	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	346	if (pdeo->inode == inode && pdeo->file == file)
	347	return pdeo;
	348	}
	349	return NULL;
	350	}
	351
786d7e16 AD	352	static int proc_reg_release(struct inode inode, struct file file)
	353	{
	354	struct proc_dir_entry *pde = PDE(inode);
	355	int rv = 0;
	356	int (release)(struct inode , struct file *);
881adb85	357	struct pde_opener *pdeo;
786d7e16 AD	358
786d7e16 AD	359	spin_lock(&pde->pde_unload_lock);
881adb85	360	pdeo = find_pde_opener(pde, inode, file);
786d7e16	361	if (!pde->proc_fops) {
881adb85 AD	362	/*
	363	* Can't simply exit, __fput() will think that everything is OK,
	364	* and move on to freeing struct file. remove_proc_entry() will
	365	* find slacker in opener's list and will try to do non-trivial
	366	* things with struct file. Therefore, remove opener from list.
	367	*
	368	* But if opener is removed from list, who will ->release it?
	369	*/
	370	if (pdeo) {
	371	list_del(&pdeo->lh);
	372	spin_unlock(&pde->pde_unload_lock);
	373	rv = pdeo->release(inode, file);
	374	kfree(pdeo);
	375	} else
	376	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	377	return rv;
	378	}
	379	pde->pde_users++;
	380	release = pde->proc_fops->release;
881adb85 AD	381	if (pdeo) {
	382	list_del(&pdeo->lh);
	383	kfree(pdeo);
	384	}
786d7e16 AD	385	spin_unlock(&pde->pde_unload_lock);
	386
	387	if (release)
	388	rv = release(inode, file);
	389
	390	pde_users_dec(pde);
	391	return rv;
	392	}
	393
	394	static const struct file_operations proc_reg_file_ops = {
	395	.llseek = proc_reg_llseek,
	396	.read = proc_reg_read,
	397	.write = proc_reg_write,
	398	.poll = proc_reg_poll,
	399	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	400	#ifdef CONFIG_COMPAT
	401	.compat_ioctl = proc_reg_compat_ioctl,
	402	#endif
	403	.mmap = proc_reg_mmap,
	404	.open = proc_reg_open,
	405	.release = proc_reg_release,
	406	};
	407
778f3dd5 DM	408	#ifdef CONFIG_COMPAT
	409	static const struct file_operations proc_reg_file_ops_no_compat = {
	410	.llseek = proc_reg_llseek,
	411	.read = proc_reg_read,
	412	.write = proc_reg_write,
	413	.poll = proc_reg_poll,
	414	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	415	.mmap = proc_reg_mmap,
	416	.open = proc_reg_open,
	417	.release = proc_reg_release,
	418	};
	419	#endif
	420
1da177e4 LT	421	struct inode proc_get_inode(struct super_block sb, unsigned int ino,
	422	struct proc_dir_entry *de)
	423	{
	424	struct inode * inode;
	425
a1d4aebb	426	inode = iget_locked(sb, ino);
1da177e4	427	if (!inode)
99b76233	428	return NULL;
a1d4aebb DH	429	if (inode->i_state & I_NEW) {
	430	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	431	PROC_I(inode)->fd = 0;
	432	PROC_I(inode)->pde = de;
5e971dce AD	433
	434	if (de->mode) {
	435	inode->i_mode = de->mode;
	436	inode->i_uid = de->uid;
	437	inode->i_gid = de->gid;
	438	}
	439	if (de->size)
	440	inode->i_size = de->size;
	441	if (de->nlink)
	442	inode->i_nlink = de->nlink;
	443	if (de->proc_iops)
	444	inode->i_op = de->proc_iops;
	445	if (de->proc_fops) {
	446	if (S_ISREG(inode->i_mode)) {
778f3dd5	447	#ifdef CONFIG_COMPAT
5e971dce AD	448	if (!de->proc_fops->compat_ioctl)
	449	inode->i_fop =
	450	&proc_reg_file_ops_no_compat;
	451	else
778f3dd5	452	#endif
5e971dce AD	453	inode->i_fop = &proc_reg_file_ops;
	454	} else {
	455	inode->i_fop = de->proc_fops;
778f3dd5	456	}
786d7e16	457	}
a1d4aebb	458	unlock_new_inode(inode);
99b76233	459	} else
135d5655	460	pde_put(de);
1da177e4	461	return inode;
1da177e4 LT	462	}
1da177e4 LT	463
07543f5c	464	int proc_fill_super(struct super_block *s)
1da177e4 LT	465	{
	466	struct inode * root_inode;
	467
92d03285	468	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
1da177e4 LT	469	s->s_blocksize = 1024;
	470	s->s_blocksize_bits = 10;
	471	s->s_magic = PROC_SUPER_MAGIC;
	472	s->s_op = &proc_sops;
	473	s->s_time_gran = 1;
	474
135d5655	475	pde_get(&proc_root);
1da177e4 LT	476	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
	477	if (!root_inode)
	478	goto out_no_root;
1da177e4 LT	479	root_inode->i_uid = 0;
	480	root_inode->i_gid = 0;
	481	s->s_root = d_alloc_root(root_inode);
	482	if (!s->s_root)
	483	goto out_no_root;
	484	return 0;
	485
	486	out_no_root:
	487	printk("proc_read_super: get root inode failed\n");
	488	iput(root_inode);
135d5655	489	pde_put(&proc_root);
1da177e4 LT	490	return -ENOMEM;
1da177e4 LT	491	}