[net-next-2.6.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)
{
	lock_kernel();
	if (!atomic_read(&de->count)) {
		printk("de_put: entry %s already free!\n", de->name);
		unlock_kernel();
		return;
	}

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

/*
 * 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);
}

int __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);
	return 0;
}

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);
	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	lock_kernel();
	39	if (!atomic_read(&de->count)) {
	40	printk("de_put: entry %s already free!\n", de->name);
1da177e4	41	unlock_kernel();
5e971dce	42	return;
1da177e4	43	}
5e971dce AD	44
	45	if (atomic_dec_and_test(&de->count))
	46	free_proc_entry(de);
	47	unlock_kernel();
1da177e4 LT	48	}
	49
	50	/*
	51	* Decrement the use count of the proc_dir_entry.
	52	*/
	53	static void proc_delete_inode(struct inode *inode)
	54	{
	55	struct proc_dir_entry *de;
1da177e4	56
fef26658 MF	57	truncate_inode_pages(&inode->i_data, 0);
fef26658 MF	58
99f89551	59	/* Stop tracking associated processes */
13b41b09	60	put_pid(PROC_I(inode)->pid);
1da177e4 LT	61
	62	/* Let go of any associated proc directory entry */
	63	de = PROC_I(inode)->pde;
	64	if (de) {
	65	if (de->owner)
	66	module_put(de->owner);
	67	de_put(de);
	68	}
9043476f AV	69	if (PROC_I(inode)->sysctl)
9043476f AV	70	sysctl_head_put(PROC_I(inode)->sysctl);
1da177e4 LT	71	clear_inode(inode);
	72	}
	73
	74	struct vfsmount *proc_mnt;
	75
e18b890b	76	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	77
	78	static struct inode proc_alloc_inode(struct super_block sb)
	79	{
	80	struct proc_inode *ei;
	81	struct inode *inode;
	82
e94b1766	83	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	84	if (!ei)
1da177e4 LT	85	return NULL;
13b41b09	86	ei->pid = NULL;
aed7a6c4	87	ei->fd = 0;
1da177e4 LT	88	ei->op.proc_get_link = NULL;
1da177e4 LT	89	ei->pde = NULL;
9043476f AV	90	ei->sysctl = NULL;
9043476f AV	91	ei->sysctl_entry = NULL;
1da177e4 LT	92	inode = &ei->vfs_inode;
	93	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	94	return inode;
	95	}
	96
	97	static void proc_destroy_inode(struct inode *inode)
	98	{
	99	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	100	}
	101
51cc5068	102	static void init_once(void *foo)
1da177e4 LT	103	{
	104	struct proc_inode ei = (struct proc_inode ) foo;
	105
a35afb83	106	inode_init_once(&ei->vfs_inode);
1da177e4	107	}
20c2df83	108
1da177e4 LT	109	int __init proc_init_inodecache(void)
	110	{
	111	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	112	sizeof(struct proc_inode),
fffb60f9	113	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	114	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	115	init_once);
1da177e4 LT	116	return 0;
	117	}
	118
ee9b6d61	119	static const struct super_operations proc_sops = {
1da177e4 LT	120	.alloc_inode = proc_alloc_inode,
1da177e4 LT	121	.destroy_inode = proc_destroy_inode,
1da177e4 LT	122	.drop_inode = generic_delete_inode,
	123	.delete_inode = proc_delete_inode,
	124	.statfs = simple_statfs,
1da177e4 LT	125	};
1da177e4 LT	126
881adb85	127	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	128	{
786d7e16 AD	129	pde->pde_users--;
	130	if (pde->pde_unload_completion && pde->pde_users == 0)
	131	complete(pde->pde_unload_completion);
881adb85 AD	132	}
	133
	134	static void pde_users_dec(struct proc_dir_entry *pde)
	135	{
	136	spin_lock(&pde->pde_unload_lock);
	137	__pde_users_dec(pde);
786d7e16 AD	138	spin_unlock(&pde->pde_unload_lock);
	139	}
	140
	141	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	142	{
	143	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	144	loff_t rv = -EINVAL;
	145	loff_t (llseek)(struct file , loff_t, int);
	146
	147	spin_lock(&pde->pde_unload_lock);
	148	/*
	149	* remove_proc_entry() is going to delete PDE (as part of module
	150	* cleanup sequence). No new callers into module allowed.
	151	*/
	152	if (!pde->proc_fops) {
	153	spin_unlock(&pde->pde_unload_lock);
	154	return rv;
	155	}
	156	/*
	157	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	158	* complete.
	159	*/
	160	pde->pde_users++;
	161	/*
	162	* Save function pointer under lock, to protect against ->proc_fops
	163	* NULL'ifying right after ->pde_unload_lock is dropped.
	164	*/
	165	llseek = pde->proc_fops->llseek;
	166	spin_unlock(&pde->pde_unload_lock);
	167
	168	if (!llseek)
	169	llseek = default_llseek;
	170	rv = llseek(file, offset, whence);
	171
	172	pde_users_dec(pde);
	173	return rv;
	174	}
	175
	176	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	177	{
	178	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	179	ssize_t rv = -EIO;
	180	ssize_t (read)(struct file , char __user , size_t, loff_t );
	181
	182	spin_lock(&pde->pde_unload_lock);
	183	if (!pde->proc_fops) {
	184	spin_unlock(&pde->pde_unload_lock);
	185	return rv;
	186	}
	187	pde->pde_users++;
	188	read = pde->proc_fops->read;
	189	spin_unlock(&pde->pde_unload_lock);
	190
	191	if (read)
	192	rv = read(file, buf, count, ppos);
	193
	194	pde_users_dec(pde);
	195	return rv;
	196	}
	197
	198	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	199	{
	200	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	201	ssize_t rv = -EIO;
202	ssize_t (write)(struct file , const char __user , size_t, loff_t );
203
204	spin_lock(&pde->pde_unload_lock);
205	if (!pde->proc_fops) {
206	spin_unlock(&pde->pde_unload_lock);
207	return rv;
208	}
209	pde->pde_users++;
210	write = pde->proc_fops->write;
211	spin_unlock(&pde->pde_unload_lock);
212
213	if (write)
214	rv = write(file, buf, count, ppos);
215
216	pde_users_dec(pde);
217	return rv;
218	}
219
220	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
221	{
222	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
dd23aae4	223	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	224	unsigned int (poll)(struct file , struct poll_table_struct *);
	225
	226	spin_lock(&pde->pde_unload_lock);
	227	if (!pde->proc_fops) {
	228	spin_unlock(&pde->pde_unload_lock);
	229	return rv;
	230	}
	231	pde->pde_users++;
	232	poll = pde->proc_fops->poll;
	233	spin_unlock(&pde->pde_unload_lock);
	234
	235	if (poll)
	236	rv = poll(file, pts);
	237
	238	pde_users_dec(pde);
	239	return rv;
	240	}
	241
	242	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	243	{
	244	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	245	long rv = -ENOTTY;
	246	long (unlocked_ioctl)(struct file , unsigned int, unsigned long);
	247	int (ioctl)(struct inode , struct file *, unsigned int, unsigned long);
	248
	249	spin_lock(&pde->pde_unload_lock);
	250	if (!pde->proc_fops) {
	251	spin_unlock(&pde->pde_unload_lock);
	252	return rv;
	253	}
	254	pde->pde_users++;
	255	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
	256	ioctl = pde->proc_fops->ioctl;
	257	spin_unlock(&pde->pde_unload_lock);
	258
	259	if (unlocked_ioctl) {
	260	rv = unlocked_ioctl(file, cmd, arg);
	261	if (rv == -ENOIOCTLCMD)
	262	rv = -EINVAL;
	263	} else if (ioctl) {
	264	lock_kernel();
	265	rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
	266	unlock_kernel();
	267	}
	268
	269	pde_users_dec(pde);
	270	return rv;
	271	}
	272
	273	#ifdef CONFIG_COMPAT
	274	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	275	{
	276	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	277	long rv = -ENOTTY;
	278	long (compat_ioctl)(struct file , unsigned int, unsigned long);
	279
	280	spin_lock(&pde->pde_unload_lock);
	281	if (!pde->proc_fops) {
	282	spin_unlock(&pde->pde_unload_lock);
	283	return rv;
	284	}
	285	pde->pde_users++;
	286	compat_ioctl = pde->proc_fops->compat_ioctl;
	287	spin_unlock(&pde->pde_unload_lock);
288
289	if (compat_ioctl)
290	rv = compat_ioctl(file, cmd, arg);
291
292	pde_users_dec(pde);
293	return rv;
294	}
295	#endif
296
297	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
298	{
299	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
300	int rv = -EIO;
301	int (mmap)(struct file , struct vm_area_struct *);
302
303	spin_lock(&pde->pde_unload_lock);
304	if (!pde->proc_fops) {
305	spin_unlock(&pde->pde_unload_lock);
306	return rv;
307	}
308	pde->pde_users++;
309	mmap = pde->proc_fops->mmap;
310	spin_unlock(&pde->pde_unload_lock);
311
312	if (mmap)
313	rv = mmap(file, vma);
314
315	pde_users_dec(pde);
316	return rv;
317	}
318
319	static int proc_reg_open(struct inode inode, struct file file)
320	{
321	struct proc_dir_entry *pde = PDE(inode);
322	int rv = 0;
323	int (open)(struct inode , struct file *);
881adb85 AD	324	int (release)(struct inode , struct file *);
	325	struct pde_opener *pdeo;
	326
	327	/*
	328	* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	329	* sequence. ->release won't be called because ->proc_fops will be
	330	* cleared. Depending on complexity of ->release, consequences vary.
	331	*
	332	* We can't wait for mercy when close will be done for real, it's
	333	* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	334	* by hand in remove_proc_entry(). For this, save opener's credentials
	335	* for later.
	336	*/
	337	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	338	if (!pdeo)
	339	return -ENOMEM;
786d7e16 AD	340
	341	spin_lock(&pde->pde_unload_lock);
	342	if (!pde->proc_fops) {
	343	spin_unlock(&pde->pde_unload_lock);
881adb85	344	kfree(pdeo);
300b994b	345	return -EINVAL;
786d7e16 AD	346	}
	347	pde->pde_users++;
	348	open = pde->proc_fops->open;
881adb85	349	release = pde->proc_fops->release;
786d7e16 AD	350	spin_unlock(&pde->pde_unload_lock);
	351
	352	if (open)
	353	rv = open(inode, file);
	354
881adb85 AD	355	spin_lock(&pde->pde_unload_lock);
	356	if (rv == 0 && release) {
	357	/* To know what to release. */
	358	pdeo->inode = inode;
	359	pdeo->file = file;
	360	/* Strictly for "too late" ->release in proc_reg_release(). */
	361	pdeo->release = release;
	362	list_add(&pdeo->lh, &pde->pde_openers);
	363	} else
	364	kfree(pdeo);
	365	__pde_users_dec(pde);
	366	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	367	return rv;
	368	}
	369
881adb85 AD	370	static struct pde_opener find_pde_opener(struct proc_dir_entry pde,
	371	struct inode inode, struct file file)
	372	{
	373	struct pde_opener *pdeo;
	374
	375	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	376	if (pdeo->inode == inode && pdeo->file == file)
	377	return pdeo;
	378	}
	379	return NULL;
	380	}
	381
786d7e16 AD	382	static int proc_reg_release(struct inode inode, struct file file)
	383	{
	384	struct proc_dir_entry *pde = PDE(inode);
	385	int rv = 0;
	386	int (release)(struct inode , struct file *);
881adb85	387	struct pde_opener *pdeo;
786d7e16 AD	388
786d7e16 AD	389	spin_lock(&pde->pde_unload_lock);
881adb85	390	pdeo = find_pde_opener(pde, inode, file);
786d7e16	391	if (!pde->proc_fops) {
881adb85 AD	392	/*
	393	* Can't simply exit, __fput() will think that everything is OK,
	394	* and move on to freeing struct file. remove_proc_entry() will
	395	* find slacker in opener's list and will try to do non-trivial
	396	* things with struct file. Therefore, remove opener from list.
	397	*
	398	* But if opener is removed from list, who will ->release it?
	399	*/
	400	if (pdeo) {
	401	list_del(&pdeo->lh);
	402	spin_unlock(&pde->pde_unload_lock);
	403	rv = pdeo->release(inode, file);
	404	kfree(pdeo);
	405	} else
	406	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	407	return rv;
	408	}
	409	pde->pde_users++;
	410	release = pde->proc_fops->release;
881adb85 AD	411	if (pdeo) {
	412	list_del(&pdeo->lh);
	413	kfree(pdeo);
	414	}
786d7e16 AD	415	spin_unlock(&pde->pde_unload_lock);
	416
	417	if (release)
	418	rv = release(inode, file);
	419
	420	pde_users_dec(pde);
	421	return rv;
	422	}
	423
	424	static const struct file_operations proc_reg_file_ops = {
	425	.llseek = proc_reg_llseek,
	426	.read = proc_reg_read,
	427	.write = proc_reg_write,
	428	.poll = proc_reg_poll,
	429	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	430	#ifdef CONFIG_COMPAT
	431	.compat_ioctl = proc_reg_compat_ioctl,
	432	#endif
	433	.mmap = proc_reg_mmap,
	434	.open = proc_reg_open,
	435	.release = proc_reg_release,
	436	};
	437
778f3dd5 DM	438	#ifdef CONFIG_COMPAT
	439	static const struct file_operations proc_reg_file_ops_no_compat = {
	440	.llseek = proc_reg_llseek,
	441	.read = proc_reg_read,
	442	.write = proc_reg_write,
	443	.poll = proc_reg_poll,
	444	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	445	.mmap = proc_reg_mmap,
	446	.open = proc_reg_open,
	447	.release = proc_reg_release,
	448	};
	449	#endif
	450
1da177e4 LT	451	struct inode proc_get_inode(struct super_block sb, unsigned int ino,
	452	struct proc_dir_entry *de)
	453	{
	454	struct inode * inode;
	455
5e971dce	456	if (!try_module_get(de->owner))
e9543659 KK	457	goto out_mod;
e9543659 KK	458
a1d4aebb	459	inode = iget_locked(sb, ino);
1da177e4	460	if (!inode)
e9543659	461	goto out_ino;
a1d4aebb DH	462	if (inode->i_state & I_NEW) {
	463	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	464	PROC_I(inode)->fd = 0;
	465	PROC_I(inode)->pde = de;
5e971dce AD	466
	467	if (de->mode) {
	468	inode->i_mode = de->mode;
	469	inode->i_uid = de->uid;
	470	inode->i_gid = de->gid;
	471	}
	472	if (de->size)
	473	inode->i_size = de->size;
	474	if (de->nlink)
	475	inode->i_nlink = de->nlink;
	476	if (de->proc_iops)
	477	inode->i_op = de->proc_iops;
	478	if (de->proc_fops) {
	479	if (S_ISREG(inode->i_mode)) {
778f3dd5	480	#ifdef CONFIG_COMPAT
5e971dce AD	481	if (!de->proc_fops->compat_ioctl)
	482	inode->i_fop =
	483	&proc_reg_file_ops_no_compat;
	484	else
778f3dd5	485	#endif
5e971dce AD	486	inode->i_fop = &proc_reg_file_ops;
	487	} else {
	488	inode->i_fop = de->proc_fops;
778f3dd5	489	}
786d7e16	490	}
a1d4aebb	491	unlock_new_inode(inode);
c4185a0e DL	492	} else
c4185a0e DL	493	module_put(de->owner);
1da177e4 LT	494	return inode;
1da177e4 LT	495
e9543659	496	out_ino:
5e971dce	497	module_put(de->owner);
e9543659	498	out_mod:
e9543659	499	return NULL;
1da177e4 LT	500	}
1da177e4 LT	501
07543f5c	502	int proc_fill_super(struct super_block *s)
1da177e4 LT	503	{
	504	struct inode * root_inode;
	505
92d03285	506	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
1da177e4 LT	507	s->s_blocksize = 1024;
	508	s->s_blocksize_bits = 10;
	509	s->s_magic = PROC_SUPER_MAGIC;
	510	s->s_op = &proc_sops;
	511	s->s_time_gran = 1;
	512
7695650a	513	de_get(&proc_root);
1da177e4 LT	514	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
	515	if (!root_inode)
	516	goto out_no_root;
1da177e4 LT	517	root_inode->i_uid = 0;
	518	root_inode->i_gid = 0;
	519	s->s_root = d_alloc_root(root_inode);
	520	if (!s->s_root)
	521	goto out_no_root;
	522	return 0;
	523
	524	out_no_root:
	525	printk("proc_read_super: get root inode failed\n");
	526	iput(root_inode);
7695650a	527	de_put(&proc_root);
1da177e4 LT	528	return -ENOMEM;
1da177e4 LT	529	}