[deliverable/linux.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)
		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);
}

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
	       de_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;
	
	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;
99b76233	61	if (de)
1da177e4	62	de_put(de);
9043476f AV	63	if (PROC_I(inode)->sysctl)
9043476f AV	64	sysctl_head_put(PROC_I(inode)->sysctl);
1da177e4 LT	65	clear_inode(inode);
	66	}
	67
	68	struct vfsmount *proc_mnt;
	69
e18b890b	70	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	71
	72	static struct inode proc_alloc_inode(struct super_block sb)
	73	{
	74	struct proc_inode *ei;
	75	struct inode *inode;
	76
e94b1766	77	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	78	if (!ei)
1da177e4 LT	79	return NULL;
13b41b09	80	ei->pid = NULL;
aed7a6c4	81	ei->fd = 0;
1da177e4 LT	82	ei->op.proc_get_link = NULL;
1da177e4 LT	83	ei->pde = NULL;
9043476f AV	84	ei->sysctl = NULL;
9043476f AV	85	ei->sysctl_entry = NULL;
1da177e4 LT	86	inode = &ei->vfs_inode;
	87	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	88	return inode;
	89	}
	90
	91	static void proc_destroy_inode(struct inode *inode)
	92	{
	93	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	94	}
	95
51cc5068	96	static void init_once(void *foo)
1da177e4 LT	97	{
	98	struct proc_inode ei = (struct proc_inode ) foo;
	99
a35afb83	100	inode_init_once(&ei->vfs_inode);
1da177e4	101	}
20c2df83	102
5bcd7ff9	103	void __init proc_init_inodecache(void)
1da177e4 LT	104	{
	105	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	106	sizeof(struct proc_inode),
fffb60f9	107	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	108	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	109	init_once);
1da177e4 LT	110	}
1da177e4 LT	111
ee9b6d61	112	static const struct super_operations proc_sops = {
1da177e4 LT	113	.alloc_inode = proc_alloc_inode,
1da177e4 LT	114	.destroy_inode = proc_destroy_inode,
1da177e4 LT	115	.drop_inode = generic_delete_inode,
	116	.delete_inode = proc_delete_inode,
	117	.statfs = simple_statfs,
1da177e4 LT	118	};
1da177e4 LT	119
881adb85	120	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	121	{
786d7e16 AD	122	pde->pde_users--;
	123	if (pde->pde_unload_completion && pde->pde_users == 0)
	124	complete(pde->pde_unload_completion);
881adb85 AD	125	}
881adb85 AD	126
3dec7f59	127	void pde_users_dec(struct proc_dir_entry *pde)
881adb85 AD	128	{
	129	spin_lock(&pde->pde_unload_lock);
	130	__pde_users_dec(pde);
786d7e16 AD	131	spin_unlock(&pde->pde_unload_lock);
	132	}
	133
	134	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	135	{
	136	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	137	loff_t rv = -EINVAL;
	138	loff_t (llseek)(struct file , loff_t, int);
	139
	140	spin_lock(&pde->pde_unload_lock);
	141	/*
	142	* remove_proc_entry() is going to delete PDE (as part of module
	143	* cleanup sequence). No new callers into module allowed.
	144	*/
	145	if (!pde->proc_fops) {
	146	spin_unlock(&pde->pde_unload_lock);
	147	return rv;
	148	}
	149	/*
	150	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	151	* complete.
	152	*/
	153	pde->pde_users++;
	154	/*
	155	* Save function pointer under lock, to protect against ->proc_fops
	156	* NULL'ifying right after ->pde_unload_lock is dropped.
	157	*/
	158	llseek = pde->proc_fops->llseek;
	159	spin_unlock(&pde->pde_unload_lock);
	160
	161	if (!llseek)
	162	llseek = default_llseek;
	163	rv = llseek(file, offset, whence);
	164
	165	pde_users_dec(pde);
	166	return rv;
	167	}
	168
	169	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	170	{
	171	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	172	ssize_t rv = -EIO;
	173	ssize_t (read)(struct file , char __user , size_t, loff_t );
	174
	175	spin_lock(&pde->pde_unload_lock);
	176	if (!pde->proc_fops) {
	177	spin_unlock(&pde->pde_unload_lock);
	178	return rv;
	179	}
	180	pde->pde_users++;
	181	read = pde->proc_fops->read;
	182	spin_unlock(&pde->pde_unload_lock);
	183
	184	if (read)
	185	rv = read(file, buf, count, ppos);
	186
	187	pde_users_dec(pde);
	188	return rv;
	189	}
	190
	191	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	192	{
	193	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	194	ssize_t rv = -EIO;
195	ssize_t (write)(struct file , const char __user , size_t, loff_t );
196
197	spin_lock(&pde->pde_unload_lock);
198	if (!pde->proc_fops) {
199	spin_unlock(&pde->pde_unload_lock);
200	return rv;
201	}
202	pde->pde_users++;
203	write = pde->proc_fops->write;
204	spin_unlock(&pde->pde_unload_lock);
205
206	if (write)
207	rv = write(file, buf, count, ppos);
208
209	pde_users_dec(pde);
210	return rv;
211	}
212
213	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
214	{
215	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
dd23aae4	216	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	217	unsigned int (poll)(struct file , struct poll_table_struct *);
	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	poll = pde->proc_fops->poll;
	226	spin_unlock(&pde->pde_unload_lock);
	227
	228	if (poll)
	229	rv = poll(file, pts);
	230
	231	pde_users_dec(pde);
	232	return rv;
	233	}
	234
	235	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	236	{
	237	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	238	long rv = -ENOTTY;
	239	long (unlocked_ioctl)(struct file , unsigned int, unsigned long);
	240	int (ioctl)(struct inode , struct file *, unsigned int, unsigned long);
	241
	242	spin_lock(&pde->pde_unload_lock);
	243	if (!pde->proc_fops) {
	244	spin_unlock(&pde->pde_unload_lock);
	245	return rv;
	246	}
	247	pde->pde_users++;
	248	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
	249	ioctl = pde->proc_fops->ioctl;
	250	spin_unlock(&pde->pde_unload_lock);
	251
	252	if (unlocked_ioctl) {
	253	rv = unlocked_ioctl(file, cmd, arg);
	254	if (rv == -ENOIOCTLCMD)
	255	rv = -EINVAL;
	256	} else if (ioctl) {
	257	lock_kernel();
	258	rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
	259	unlock_kernel();
	260	}
	261
	262	pde_users_dec(pde);
	263	return rv;
	264	}
	265
	266	#ifdef CONFIG_COMPAT
	267	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	268	{
	269	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	270	long rv = -ENOTTY;
	271	long (compat_ioctl)(struct file , unsigned int, unsigned long);
	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	compat_ioctl = pde->proc_fops->compat_ioctl;
	280	spin_unlock(&pde->pde_unload_lock);
281
282	if (compat_ioctl)
283	rv = compat_ioctl(file, cmd, arg);
284
285	pde_users_dec(pde);
286	return rv;
287	}
288	#endif
289
290	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
291	{
292	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
293	int rv = -EIO;
294	int (mmap)(struct file , struct vm_area_struct *);
295
296	spin_lock(&pde->pde_unload_lock);
297	if (!pde->proc_fops) {
298	spin_unlock(&pde->pde_unload_lock);
299	return rv;
300	}
301	pde->pde_users++;
302	mmap = pde->proc_fops->mmap;
303	spin_unlock(&pde->pde_unload_lock);
304
305	if (mmap)
306	rv = mmap(file, vma);
307
308	pde_users_dec(pde);
309	return rv;
310	}
311
312	static int proc_reg_open(struct inode inode, struct file file)
313	{
314	struct proc_dir_entry *pde = PDE(inode);
315	int rv = 0;
316	int (open)(struct inode , struct file *);
881adb85 AD	317	int (release)(struct inode , struct file *);
	318	struct pde_opener *pdeo;
	319
	320	/*
	321	* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	322	* sequence. ->release won't be called because ->proc_fops will be
	323	* cleared. Depending on complexity of ->release, consequences vary.
	324	*
	325	* We can't wait for mercy when close will be done for real, it's
	326	* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	327	* by hand in remove_proc_entry(). For this, save opener's credentials
	328	* for later.
	329	*/
	330	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	331	if (!pdeo)
	332	return -ENOMEM;
786d7e16 AD	333
	334	spin_lock(&pde->pde_unload_lock);
	335	if (!pde->proc_fops) {
	336	spin_unlock(&pde->pde_unload_lock);
881adb85	337	kfree(pdeo);
300b994b	338	return -EINVAL;
786d7e16 AD	339	}
	340	pde->pde_users++;
	341	open = pde->proc_fops->open;
881adb85	342	release = pde->proc_fops->release;
786d7e16 AD	343	spin_unlock(&pde->pde_unload_lock);
	344
	345	if (open)
	346	rv = open(inode, file);
	347
881adb85 AD	348	spin_lock(&pde->pde_unload_lock);
	349	if (rv == 0 && release) {
	350	/* To know what to release. */
	351	pdeo->inode = inode;
	352	pdeo->file = file;
	353	/* Strictly for "too late" ->release in proc_reg_release(). */
	354	pdeo->release = release;
	355	list_add(&pdeo->lh, &pde->pde_openers);
	356	} else
	357	kfree(pdeo);
	358	__pde_users_dec(pde);
	359	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	360	return rv;
	361	}
	362
881adb85 AD	363	static struct pde_opener find_pde_opener(struct proc_dir_entry pde,
	364	struct inode inode, struct file file)
	365	{
	366	struct pde_opener *pdeo;
	367
	368	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	369	if (pdeo->inode == inode && pdeo->file == file)
	370	return pdeo;
	371	}
	372	return NULL;
	373	}
	374
786d7e16 AD	375	static int proc_reg_release(struct inode inode, struct file file)
	376	{
	377	struct proc_dir_entry *pde = PDE(inode);
	378	int rv = 0;
	379	int (release)(struct inode , struct file *);
881adb85	380	struct pde_opener *pdeo;
786d7e16 AD	381
786d7e16 AD	382	spin_lock(&pde->pde_unload_lock);
881adb85	383	pdeo = find_pde_opener(pde, inode, file);
786d7e16	384	if (!pde->proc_fops) {
881adb85 AD	385	/*
	386	* Can't simply exit, __fput() will think that everything is OK,
	387	* and move on to freeing struct file. remove_proc_entry() will
	388	* find slacker in opener's list and will try to do non-trivial
	389	* things with struct file. Therefore, remove opener from list.
	390	*
	391	* But if opener is removed from list, who will ->release it?
	392	*/
	393	if (pdeo) {
	394	list_del(&pdeo->lh);
	395	spin_unlock(&pde->pde_unload_lock);
	396	rv = pdeo->release(inode, file);
	397	kfree(pdeo);
	398	} else
	399	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	400	return rv;
	401	}
	402	pde->pde_users++;
	403	release = pde->proc_fops->release;
881adb85 AD	404	if (pdeo) {
	405	list_del(&pdeo->lh);
	406	kfree(pdeo);
	407	}
786d7e16 AD	408	spin_unlock(&pde->pde_unload_lock);
	409
	410	if (release)
	411	rv = release(inode, file);
	412
	413	pde_users_dec(pde);
	414	return rv;
	415	}
	416
	417	static const struct file_operations proc_reg_file_ops = {
	418	.llseek = proc_reg_llseek,
	419	.read = proc_reg_read,
	420	.write = proc_reg_write,
	421	.poll = proc_reg_poll,
	422	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	423	#ifdef CONFIG_COMPAT
	424	.compat_ioctl = proc_reg_compat_ioctl,
	425	#endif
	426	.mmap = proc_reg_mmap,
	427	.open = proc_reg_open,
	428	.release = proc_reg_release,
	429	};
	430
778f3dd5 DM	431	#ifdef CONFIG_COMPAT
	432	static const struct file_operations proc_reg_file_ops_no_compat = {
	433	.llseek = proc_reg_llseek,
	434	.read = proc_reg_read,
	435	.write = proc_reg_write,
	436	.poll = proc_reg_poll,
	437	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	438	.mmap = proc_reg_mmap,
	439	.open = proc_reg_open,
	440	.release = proc_reg_release,
	441	};
	442	#endif
	443
1da177e4 LT	444	struct inode proc_get_inode(struct super_block sb, unsigned int ino,
	445	struct proc_dir_entry *de)
	446	{
	447	struct inode * inode;
	448
a1d4aebb	449	inode = iget_locked(sb, ino);
1da177e4	450	if (!inode)
99b76233	451	return NULL;
a1d4aebb DH	452	if (inode->i_state & I_NEW) {
	453	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	454	PROC_I(inode)->fd = 0;
	455	PROC_I(inode)->pde = de;
5e971dce AD	456
	457	if (de->mode) {
	458	inode->i_mode = de->mode;
	459	inode->i_uid = de->uid;
	460	inode->i_gid = de->gid;
	461	}
	462	if (de->size)
	463	inode->i_size = de->size;
	464	if (de->nlink)
	465	inode->i_nlink = de->nlink;
	466	if (de->proc_iops)
	467	inode->i_op = de->proc_iops;
	468	if (de->proc_fops) {
	469	if (S_ISREG(inode->i_mode)) {
778f3dd5	470	#ifdef CONFIG_COMPAT
5e971dce AD	471	if (!de->proc_fops->compat_ioctl)
	472	inode->i_fop =
	473	&proc_reg_file_ops_no_compat;
	474	else
778f3dd5	475	#endif
5e971dce AD	476	inode->i_fop = &proc_reg_file_ops;
	477	} else {
	478	inode->i_fop = de->proc_fops;
778f3dd5	479	}
786d7e16	480	}
a1d4aebb	481	unlock_new_inode(inode);
99b76233	482	} else
cac71121	483	de_put(de);
1da177e4	484	return inode;
1da177e4 LT	485	}
1da177e4 LT	486
07543f5c	487	int proc_fill_super(struct super_block *s)
1da177e4 LT	488	{
	489	struct inode * root_inode;
	490
92d03285	491	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
1da177e4 LT	492	s->s_blocksize = 1024;
	493	s->s_blocksize_bits = 10;
	494	s->s_magic = PROC_SUPER_MAGIC;
	495	s->s_op = &proc_sops;
	496	s->s_time_gran = 1;
	497
7695650a	498	de_get(&proc_root);
1da177e4 LT	499	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
	500	if (!root_inode)
	501	goto out_no_root;
1da177e4 LT	502	root_inode->i_uid = 0;
	503	root_inode->i_gid = 0;
	504	s->s_root = d_alloc_root(root_inode);
	505	if (!s->s_root)
	506	goto out_no_root;
	507	return 0;
	508
	509	out_no_root:
	510	printk("proc_read_super: get root inode failed\n");
	511	iput(root_inode);
7695650a	512	de_put(&proc_root);
1da177e4 LT	513	return -ENOMEM;
1da177e4 LT	514	}