[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"

struct proc_dir_entry *de_get(struct proc_dir_entry *de)
{
	atomic_inc(&de->count);
	return de;
}

/*
 * Decrements the use count and checks for deferred deletion.
 */
void de_put(struct proc_dir_entry *de)
{
	if (!atomic_read(&de->count)) {
		printk("de_put: entry %s already free!\n", de->name);
		return;
	}

	if (atomic_dec_and_test(&de->count))
		free_proc_entry(de);
}

/*
 * Decrement the use count of the proc_dir_entry.
 */
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) {
		if (de->owner)
			module_put(de->owner);
		de_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);
}

static 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;

	if (!try_module_get(de->owner))
		goto out_mod;

	inode = iget_locked(sb, ino);
	if (!inode)
		goto out_ino;
	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 {
	       module_put(de->owner);
	       de_put(de);
	}
	return inode;

out_ino:
	module_put(de->owner);
out_mod:
	return NULL;
}			

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;
	
	de_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);
	de_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
7695650a	27	struct proc_dir_entry de_get(struct proc_dir_entry de)
1da177e4	28	{
5e971dce	29	atomic_inc(&de->count);
1da177e4 LT	30	return de;
	31	}
	32
	33	/*
	34	* Decrements the use count and checks for deferred deletion.
	35	*/
7695650a	36	void de_put(struct proc_dir_entry *de)
1da177e4	37	{
5e971dce AD	38	if (!atomic_read(&de->count)) {
5e971dce AD	39	printk("de_put: entry %s already free!\n", de->name);
5e971dce	40	return;
1da177e4	41	}
5e971dce AD	42
	43	if (atomic_dec_and_test(&de->count))
	44	free_proc_entry(de);
1da177e4 LT	45	}
	46
	47	/*
	48	* Decrement the use count of the proc_dir_entry.
	49	*/
	50	static void proc_delete_inode(struct inode *inode)
	51	{
	52	struct proc_dir_entry *de;
1da177e4	53
fef26658 MF	54	truncate_inode_pages(&inode->i_data, 0);
fef26658 MF	55
99f89551	56	/* Stop tracking associated processes */
13b41b09	57	put_pid(PROC_I(inode)->pid);
1da177e4 LT	58
	59	/* Let go of any associated proc directory entry */
	60	de = PROC_I(inode)->pde;
	61	if (de) {
	62	if (de->owner)
	63	module_put(de->owner);
	64	de_put(de);
	65	}
9043476f AV	66	if (PROC_I(inode)->sysctl)
9043476f AV	67	sysctl_head_put(PROC_I(inode)->sysctl);
1da177e4 LT	68	clear_inode(inode);
	69	}
	70
	71	struct vfsmount *proc_mnt;
	72
e18b890b	73	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	74
	75	static struct inode proc_alloc_inode(struct super_block sb)
	76	{
	77	struct proc_inode *ei;
	78	struct inode *inode;
	79
e94b1766	80	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	81	if (!ei)
1da177e4 LT	82	return NULL;
13b41b09	83	ei->pid = NULL;
aed7a6c4	84	ei->fd = 0;
1da177e4 LT	85	ei->op.proc_get_link = NULL;
1da177e4 LT	86	ei->pde = NULL;
9043476f AV	87	ei->sysctl = NULL;
9043476f AV	88	ei->sysctl_entry = NULL;
1da177e4 LT	89	inode = &ei->vfs_inode;
	90	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	91	return inode;
	92	}
	93
	94	static void proc_destroy_inode(struct inode *inode)
	95	{
	96	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	97	}
	98
51cc5068	99	static void init_once(void *foo)
1da177e4 LT	100	{
	101	struct proc_inode ei = (struct proc_inode ) foo;
	102
a35afb83	103	inode_init_once(&ei->vfs_inode);
1da177e4	104	}
20c2df83	105
5bcd7ff9	106	void __init proc_init_inodecache(void)
1da177e4 LT	107	{
	108	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	109	sizeof(struct proc_inode),
fffb60f9	110	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	111	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	112	init_once);
1da177e4 LT	113	}
1da177e4 LT	114
ee9b6d61	115	static const struct super_operations proc_sops = {
1da177e4 LT	116	.alloc_inode = proc_alloc_inode,
1da177e4 LT	117	.destroy_inode = proc_destroy_inode,
1da177e4 LT	118	.drop_inode = generic_delete_inode,
	119	.delete_inode = proc_delete_inode,
	120	.statfs = simple_statfs,
1da177e4 LT	121	};
1da177e4 LT	122
881adb85	123	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	124	{
786d7e16 AD	125	pde->pde_users--;
	126	if (pde->pde_unload_completion && pde->pde_users == 0)
	127	complete(pde->pde_unload_completion);
881adb85 AD	128	}
	129
	130	static void pde_users_dec(struct proc_dir_entry *pde)
	131	{
	132	spin_lock(&pde->pde_unload_lock);
	133	__pde_users_dec(pde);
786d7e16 AD	134	spin_unlock(&pde->pde_unload_lock);
	135	}
	136
	137	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	138	{
	139	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	140	loff_t rv = -EINVAL;
	141	loff_t (llseek)(struct file , loff_t, int);
	142
	143	spin_lock(&pde->pde_unload_lock);
	144	/*
	145	* remove_proc_entry() is going to delete PDE (as part of module
	146	* cleanup sequence). No new callers into module allowed.
	147	*/
	148	if (!pde->proc_fops) {
	149	spin_unlock(&pde->pde_unload_lock);
	150	return rv;
	151	}
	152	/*
	153	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	154	* complete.
	155	*/
	156	pde->pde_users++;
	157	/*
	158	* Save function pointer under lock, to protect against ->proc_fops
	159	* NULL'ifying right after ->pde_unload_lock is dropped.
	160	*/
	161	llseek = pde->proc_fops->llseek;
	162	spin_unlock(&pde->pde_unload_lock);
	163
	164	if (!llseek)
	165	llseek = default_llseek;
	166	rv = llseek(file, offset, whence);
	167
	168	pde_users_dec(pde);
	169	return rv;
	170	}
	171
	172	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	173	{
	174	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	175	ssize_t rv = -EIO;
	176	ssize_t (read)(struct file , char __user , size_t, loff_t );
	177
	178	spin_lock(&pde->pde_unload_lock);
	179	if (!pde->proc_fops) {
	180	spin_unlock(&pde->pde_unload_lock);
	181	return rv;
	182	}
	183	pde->pde_users++;
	184	read = pde->proc_fops->read;
	185	spin_unlock(&pde->pde_unload_lock);
	186
	187	if (read)
	188	rv = read(file, buf, count, ppos);
	189
	190	pde_users_dec(pde);
	191	return rv;
	192	}
	193
	194	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	195	{
	196	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	197	ssize_t rv = -EIO;
198	ssize_t (write)(struct file , const char __user , size_t, loff_t );
199
200	spin_lock(&pde->pde_unload_lock);
201	if (!pde->proc_fops) {
202	spin_unlock(&pde->pde_unload_lock);
203	return rv;
204	}
205	pde->pde_users++;
206	write = pde->proc_fops->write;
207	spin_unlock(&pde->pde_unload_lock);
208
209	if (write)
210	rv = write(file, buf, count, ppos);
211
212	pde_users_dec(pde);
213	return rv;
214	}
215
216	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
217	{
218	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
dd23aae4	219	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	220	unsigned int (poll)(struct file , struct poll_table_struct *);
	221
	222	spin_lock(&pde->pde_unload_lock);
	223	if (!pde->proc_fops) {
	224	spin_unlock(&pde->pde_unload_lock);
	225	return rv;
	226	}
	227	pde->pde_users++;
	228	poll = pde->proc_fops->poll;
	229	spin_unlock(&pde->pde_unload_lock);
	230
	231	if (poll)
	232	rv = poll(file, pts);
	233
	234	pde_users_dec(pde);
	235	return rv;
	236	}
	237
	238	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	239	{
	240	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	241	long rv = -ENOTTY;
	242	long (unlocked_ioctl)(struct file , unsigned int, unsigned long);
	243	int (ioctl)(struct inode , struct file *, unsigned int, unsigned long);
	244
	245	spin_lock(&pde->pde_unload_lock);
	246	if (!pde->proc_fops) {
	247	spin_unlock(&pde->pde_unload_lock);
	248	return rv;
	249	}
	250	pde->pde_users++;
	251	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
	252	ioctl = pde->proc_fops->ioctl;
	253	spin_unlock(&pde->pde_unload_lock);
	254
	255	if (unlocked_ioctl) {
	256	rv = unlocked_ioctl(file, cmd, arg);
	257	if (rv == -ENOIOCTLCMD)
	258	rv = -EINVAL;
	259	} else if (ioctl) {
	260	lock_kernel();
	261	rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
	262	unlock_kernel();
	263	}
	264
	265	pde_users_dec(pde);
	266	return rv;
	267	}
	268
	269	#ifdef CONFIG_COMPAT
	270	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	271	{
	272	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	273	long rv = -ENOTTY;
	274	long (compat_ioctl)(struct file , unsigned int, unsigned long);
	275
	276	spin_lock(&pde->pde_unload_lock);
	277	if (!pde->proc_fops) {
	278	spin_unlock(&pde->pde_unload_lock);
	279	return rv;
	280	}
	281	pde->pde_users++;
	282	compat_ioctl = pde->proc_fops->compat_ioctl;
	283	spin_unlock(&pde->pde_unload_lock);
284
285	if (compat_ioctl)
286	rv = compat_ioctl(file, cmd, arg);
287
288	pde_users_dec(pde);
289	return rv;
290	}
291	#endif
292
293	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
294	{
295	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
296	int rv = -EIO;
297	int (mmap)(struct file , struct vm_area_struct *);
298
299	spin_lock(&pde->pde_unload_lock);
300	if (!pde->proc_fops) {
301	spin_unlock(&pde->pde_unload_lock);
302	return rv;
303	}
304	pde->pde_users++;
305	mmap = pde->proc_fops->mmap;
306	spin_unlock(&pde->pde_unload_lock);
307
308	if (mmap)
309	rv = mmap(file, vma);
310
311	pde_users_dec(pde);
312	return rv;
313	}
314
315	static int proc_reg_open(struct inode inode, struct file file)
316	{
317	struct proc_dir_entry *pde = PDE(inode);
318	int rv = 0;
319	int (open)(struct inode , struct file *);
881adb85 AD	320	int (release)(struct inode , struct file *);
	321	struct pde_opener *pdeo;
	322
	323	/*
	324	* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	325	* sequence. ->release won't be called because ->proc_fops will be
	326	* cleared. Depending on complexity of ->release, consequences vary.
	327	*
	328	* We can't wait for mercy when close will be done for real, it's
	329	* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	330	* by hand in remove_proc_entry(). For this, save opener's credentials
	331	* for later.
	332	*/
	333	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	334	if (!pdeo)
	335	return -ENOMEM;
786d7e16 AD	336
	337	spin_lock(&pde->pde_unload_lock);
	338	if (!pde->proc_fops) {
	339	spin_unlock(&pde->pde_unload_lock);
881adb85	340	kfree(pdeo);
300b994b	341	return -EINVAL;
786d7e16 AD	342	}
	343	pde->pde_users++;
	344	open = pde->proc_fops->open;
881adb85	345	release = pde->proc_fops->release;
786d7e16 AD	346	spin_unlock(&pde->pde_unload_lock);
	347
	348	if (open)
	349	rv = open(inode, file);
	350
881adb85 AD	351	spin_lock(&pde->pde_unload_lock);
	352	if (rv == 0 && release) {
	353	/* To know what to release. */
	354	pdeo->inode = inode;
	355	pdeo->file = file;
	356	/* Strictly for "too late" ->release in proc_reg_release(). */
	357	pdeo->release = release;
	358	list_add(&pdeo->lh, &pde->pde_openers);
	359	} else
	360	kfree(pdeo);
	361	__pde_users_dec(pde);
	362	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	363	return rv;
	364	}
	365
881adb85 AD	366	static struct pde_opener find_pde_opener(struct proc_dir_entry pde,
	367	struct inode inode, struct file file)
	368	{
	369	struct pde_opener *pdeo;
	370
	371	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	372	if (pdeo->inode == inode && pdeo->file == file)
	373	return pdeo;
	374	}
	375	return NULL;
	376	}
	377
786d7e16 AD	378	static int proc_reg_release(struct inode inode, struct file file)
	379	{
	380	struct proc_dir_entry *pde = PDE(inode);
	381	int rv = 0;
	382	int (release)(struct inode , struct file *);
881adb85	383	struct pde_opener *pdeo;
786d7e16 AD	384
786d7e16 AD	385	spin_lock(&pde->pde_unload_lock);
881adb85	386	pdeo = find_pde_opener(pde, inode, file);
786d7e16	387	if (!pde->proc_fops) {
881adb85 AD	388	/*
	389	* Can't simply exit, __fput() will think that everything is OK,
	390	* and move on to freeing struct file. remove_proc_entry() will
	391	* find slacker in opener's list and will try to do non-trivial
	392	* things with struct file. Therefore, remove opener from list.
	393	*
	394	* But if opener is removed from list, who will ->release it?
	395	*/
	396	if (pdeo) {
	397	list_del(&pdeo->lh);
	398	spin_unlock(&pde->pde_unload_lock);
	399	rv = pdeo->release(inode, file);
	400	kfree(pdeo);
	401	} else
	402	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	403	return rv;
	404	}
	405	pde->pde_users++;
	406	release = pde->proc_fops->release;
881adb85 AD	407	if (pdeo) {
	408	list_del(&pdeo->lh);
	409	kfree(pdeo);
	410	}
786d7e16 AD	411	spin_unlock(&pde->pde_unload_lock);
	412
	413	if (release)
	414	rv = release(inode, file);
	415
	416	pde_users_dec(pde);
	417	return rv;
	418	}
	419
	420	static const struct file_operations proc_reg_file_ops = {
	421	.llseek = proc_reg_llseek,
	422	.read = proc_reg_read,
	423	.write = proc_reg_write,
	424	.poll = proc_reg_poll,
	425	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	426	#ifdef CONFIG_COMPAT
	427	.compat_ioctl = proc_reg_compat_ioctl,
	428	#endif
	429	.mmap = proc_reg_mmap,
	430	.open = proc_reg_open,
	431	.release = proc_reg_release,
	432	};
	433
778f3dd5 DM	434	#ifdef CONFIG_COMPAT
	435	static const struct file_operations proc_reg_file_ops_no_compat = {
	436	.llseek = proc_reg_llseek,
	437	.read = proc_reg_read,
	438	.write = proc_reg_write,
	439	.poll = proc_reg_poll,
	440	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	441	.mmap = proc_reg_mmap,
	442	.open = proc_reg_open,
	443	.release = proc_reg_release,
	444	};
	445	#endif
	446
1da177e4 LT	447	struct inode proc_get_inode(struct super_block sb, unsigned int ino,
	448	struct proc_dir_entry *de)
	449	{
	450	struct inode * inode;
	451
5e971dce	452	if (!try_module_get(de->owner))
e9543659 KK	453	goto out_mod;
e9543659 KK	454
a1d4aebb	455	inode = iget_locked(sb, ino);
1da177e4	456	if (!inode)
e9543659	457	goto out_ino;
a1d4aebb DH	458	if (inode->i_state & I_NEW) {
	459	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	460	PROC_I(inode)->fd = 0;
	461	PROC_I(inode)->pde = de;
5e971dce AD	462
	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)
	471	inode->i_nlink = de->nlink;
	472	if (de->proc_iops)
	473	inode->i_op = de->proc_iops;
	474	if (de->proc_fops) {
	475	if (S_ISREG(inode->i_mode)) {
778f3dd5	476	#ifdef CONFIG_COMPAT
5e971dce AD	477	if (!de->proc_fops->compat_ioctl)
	478	inode->i_fop =
	479	&proc_reg_file_ops_no_compat;
	480	else
778f3dd5	481	#endif
5e971dce AD	482	inode->i_fop = &proc_reg_file_ops;
	483	} else {
	484	inode->i_fop = de->proc_fops;
778f3dd5	485	}
786d7e16	486	}
a1d4aebb	487	unlock_new_inode(inode);
cac71121	488	} else {
c4185a0e	489	module_put(de->owner);
cac71121 KS	490	de_put(de);
cac71121 KS	491	}
1da177e4 LT	492	return inode;
1da177e4 LT	493
e9543659	494	out_ino:
5e971dce	495	module_put(de->owner);
e9543659	496	out_mod:
e9543659	497	return NULL;
1da177e4 LT	498	}
1da177e4 LT	499
07543f5c	500	int proc_fill_super(struct super_block *s)
1da177e4 LT	501	{
	502	struct inode * root_inode;
	503
92d03285	504	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
1da177e4 LT	505	s->s_blocksize = 1024;
	506	s->s_blocksize_bits = 10;
	507	s->s_magic = PROC_SUPER_MAGIC;
	508	s->s_op = &proc_sops;
	509	s->s_time_gran = 1;
	510
7695650a	511	de_get(&proc_root);
1da177e4 LT	512	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
	513	if (!root_inode)
	514	goto out_no_root;
1da177e4 LT	515	root_inode->i_uid = 0;
	516	root_inode->i_gid = 0;
	517	s->s_root = d_alloc_root(root_inode);
	518	if (!s->s_root)
	519	goto out_no_root;
	520	return 0;
	521
	522	out_no_root:
	523	printk("proc_read_super: get root inode failed\n");
	524	iput(root_inode);
7695650a	525	de_put(&proc_root);
1da177e4 LT	526	return -ENOMEM;
1da177e4 LT	527	}