[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/pid_namespace.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/completion.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/limits.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sysctl.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/mount.h>

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

#include "internal.h"

static void proc_evict_inode(struct inode *inode)
{
	struct proc_dir_entry *de;
	struct ctl_table_header *head;
	const struct proc_ns_operations *ns_ops;

	truncate_inode_pages(&inode->i_data, 0);
	end_writeback(inode);

	/* 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);
	head = PROC_I(inode)->sysctl;
	if (head) {
		rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);
		sysctl_head_put(head);
	}
	/* Release any associated namespace */
	ns_ops = PROC_I(inode)->ns_ops;
	if (ns_ops && ns_ops->put)
		ns_ops->put(PROC_I(inode)->ns);
}

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;
	ei->ns = NULL;
	ei->ns_ops = NULL;
	inode = &ei->vfs_inode;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	return inode;
}

static void proc_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
}

static void proc_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, proc_i_callback);
}

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 int proc_show_options(struct seq_file *seq, struct dentry *root)
{
	struct super_block *sb = root->d_sb;
	struct pid_namespace *pid = sb->s_fs_info;

	if (pid->pid_gid)
		seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid);
	if (pid->hide_pid != 0)
		seq_printf(seq, ",hidepid=%u", pid->hide_pid);

	return 0;
}

static const struct super_operations proc_sops = {
	.alloc_inode	= proc_alloc_inode,
	.destroy_inode	= proc_destroy_inode,
	.drop_inode	= generic_delete_inode,
	.evict_inode	= proc_evict_inode,
	.statfs		= simple_statfs,
	.remount_fs	= proc_remount,
	.show_options	= proc_show_options,
};

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 (*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++;
	ioctl = pde->proc_fops->unlocked_ioctl;
	spin_unlock(&pde->pde_unload_lock);

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

	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 -ENOENT;
	}
	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, struct proc_dir_entry *de)
{
	struct inode * inode;

	inode = iget_locked(sb, de->low_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)
			set_nlink(inode, 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);
	if (!root_inode)
		goto out_no_root;
	s->s_root = d_alloc_root(root_inode);
	if (!s->s_root) {
		iput(root_inode);
		goto out_no_root;
	}
	return 0;

out_no_root:
	printk("proc_read_super: get root inode failed\n");
	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>
97412950	10	#include <linux/pid_namespace.h>
1da177e4 LT	11	#include <linux/mm.h>
	12	#include <linux/string.h>
	13	#include <linux/stat.h>
786d7e16	14	#include <linux/completion.h>
dd23aae4	15	#include <linux/poll.h>
1da177e4 LT	16	#include <linux/file.h>
	17	#include <linux/limits.h>
	18	#include <linux/init.h>
	19	#include <linux/module.h>
9043476f	20	#include <linux/sysctl.h>
97412950	21	#include <linux/seq_file.h>
5a0e3ad6	22	#include <linux/slab.h>
97412950	23	#include <linux/mount.h>
1da177e4 LT	24
	25	#include <asm/system.h>
	26	#include <asm/uaccess.h>
	27
fee781e6	28	#include "internal.h"
1da177e4	29
8267952b	30	static void proc_evict_inode(struct inode *inode)
1da177e4 LT	31	{
1da177e4 LT	32	struct proc_dir_entry *de;
dfef6dcd	33	struct ctl_table_header *head;
6b4e306a	34	const struct proc_ns_operations *ns_ops;
1da177e4	35
fef26658	36	truncate_inode_pages(&inode->i_data, 0);
8267952b	37	end_writeback(inode);
fef26658	38
99f89551	39	/* Stop tracking associated processes */
13b41b09	40	put_pid(PROC_I(inode)->pid);
1da177e4 LT	41
	42	/* Let go of any associated proc directory entry */
	43	de = PROC_I(inode)->pde;
99b76233	44	if (de)
135d5655	45	pde_put(de);
dfef6dcd AV	46	head = PROC_I(inode)->sysctl;
	47	if (head) {
	48	rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);
	49	sysctl_head_put(head);
	50	}
6b4e306a EB	51	/* Release any associated namespace */
	52	ns_ops = PROC_I(inode)->ns_ops;
	53	if (ns_ops && ns_ops->put)
	54	ns_ops->put(PROC_I(inode)->ns);
1da177e4 LT	55	}
1da177e4 LT	56
e18b890b	57	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	58
	59	static struct inode proc_alloc_inode(struct super_block sb)
	60	{
	61	struct proc_inode *ei;
	62	struct inode *inode;
	63
e94b1766	64	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	65	if (!ei)
1da177e4 LT	66	return NULL;
13b41b09	67	ei->pid = NULL;
aed7a6c4	68	ei->fd = 0;
1da177e4 LT	69	ei->op.proc_get_link = NULL;
1da177e4 LT	70	ei->pde = NULL;
9043476f AV	71	ei->sysctl = NULL;
9043476f AV	72	ei->sysctl_entry = NULL;
6b4e306a EB	73	ei->ns = NULL;
6b4e306a EB	74	ei->ns_ops = NULL;
1da177e4 LT	75	inode = &ei->vfs_inode;
	76	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	77	return inode;
	78	}
	79
fa0d7e3d	80	static void proc_i_callback(struct rcu_head *head)
1da177e4	81	{
fa0d7e3d	82	struct inode *inode = container_of(head, struct inode, i_rcu);
1da177e4 LT	83	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	84	}
	85
fa0d7e3d NP	86	static void proc_destroy_inode(struct inode *inode)
	87	{
	88	call_rcu(&inode->i_rcu, proc_i_callback);
	89	}
	90
51cc5068	91	static void init_once(void *foo)
1da177e4 LT	92	{
	93	struct proc_inode ei = (struct proc_inode ) foo;
	94
a35afb83	95	inode_init_once(&ei->vfs_inode);
1da177e4	96	}
20c2df83	97
5bcd7ff9	98	void __init proc_init_inodecache(void)
1da177e4 LT	99	{
	100	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	101	sizeof(struct proc_inode),
fffb60f9	102	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	103	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	104	init_once);
1da177e4 LT	105	}
1da177e4 LT	106
97412950 VK	107	static int proc_show_options(struct seq_file seq, struct dentry root)
97412950 VK	108	{
0499680a VK	109	struct super_block *sb = root->d_sb;
	110	struct pid_namespace *pid = sb->s_fs_info;
	111
	112	if (pid->pid_gid)
	113	seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid);
	114	if (pid->hide_pid != 0)
	115	seq_printf(seq, ",hidepid=%u", pid->hide_pid);
	116
97412950 VK	117	return 0;
	118	}
	119
ee9b6d61	120	static const struct super_operations proc_sops = {
1da177e4 LT	121	.alloc_inode = proc_alloc_inode,
1da177e4 LT	122	.destroy_inode = proc_destroy_inode,
1da177e4	123	.drop_inode = generic_delete_inode,
8267952b	124	.evict_inode = proc_evict_inode,
1da177e4	125	.statfs = simple_statfs,
97412950 VK	126	.remount_fs = proc_remount,
97412950 VK	127	.show_options = proc_show_options,
1da177e4 LT	128	};
1da177e4 LT	129
881adb85	130	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	131	{
786d7e16 AD	132	pde->pde_users--;
	133	if (pde->pde_unload_completion && pde->pde_users == 0)
	134	complete(pde->pde_unload_completion);
881adb85 AD	135	}
881adb85 AD	136
3dec7f59	137	void pde_users_dec(struct proc_dir_entry *pde)
881adb85 AD	138	{
	139	spin_lock(&pde->pde_unload_lock);
	140	__pde_users_dec(pde);
786d7e16 AD	141	spin_unlock(&pde->pde_unload_lock);
	142	}
	143
	144	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	145	{
	146	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	147	loff_t rv = -EINVAL;
	148	loff_t (llseek)(struct file , loff_t, int);
	149
	150	spin_lock(&pde->pde_unload_lock);
	151	/*
	152	* remove_proc_entry() is going to delete PDE (as part of module
	153	* cleanup sequence). No new callers into module allowed.
	154	*/
	155	if (!pde->proc_fops) {
	156	spin_unlock(&pde->pde_unload_lock);
	157	return rv;
	158	}
	159	/*
	160	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	161	* complete.
	162	*/
	163	pde->pde_users++;
	164	/*
	165	* Save function pointer under lock, to protect against ->proc_fops
	166	* NULL'ifying right after ->pde_unload_lock is dropped.
	167	*/
	168	llseek = pde->proc_fops->llseek;
	169	spin_unlock(&pde->pde_unload_lock);
	170
	171	if (!llseek)
	172	llseek = default_llseek;
	173	rv = llseek(file, offset, whence);
	174
	175	pde_users_dec(pde);
	176	return rv;
	177	}
	178
	179	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	180	{
	181	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	182	ssize_t rv = -EIO;
	183	ssize_t (read)(struct file , char __user , size_t, loff_t );
	184
	185	spin_lock(&pde->pde_unload_lock);
	186	if (!pde->proc_fops) {
	187	spin_unlock(&pde->pde_unload_lock);
	188	return rv;
	189	}
	190	pde->pde_users++;
	191	read = pde->proc_fops->read;
	192	spin_unlock(&pde->pde_unload_lock);
	193
	194	if (read)
	195	rv = read(file, buf, count, ppos);
	196
	197	pde_users_dec(pde);
	198	return rv;
	199	}
	200
	201	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	202	{
	203	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	204	ssize_t rv = -EIO;
205	ssize_t (write)(struct file , const char __user , size_t, loff_t );
206
207	spin_lock(&pde->pde_unload_lock);
208	if (!pde->proc_fops) {
209	spin_unlock(&pde->pde_unload_lock);
210	return rv;
211	}
212	pde->pde_users++;
213	write = pde->proc_fops->write;
214	spin_unlock(&pde->pde_unload_lock);
215
216	if (write)
217	rv = write(file, buf, count, ppos);
218
219	pde_users_dec(pde);
220	return rv;
221	}
222
223	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
224	{
225	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
dd23aae4	226	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	227	unsigned int (poll)(struct file , struct poll_table_struct *);
	228
	229	spin_lock(&pde->pde_unload_lock);
	230	if (!pde->proc_fops) {
	231	spin_unlock(&pde->pde_unload_lock);
	232	return rv;
	233	}
	234	pde->pde_users++;
	235	poll = pde->proc_fops->poll;
	236	spin_unlock(&pde->pde_unload_lock);
	237
	238	if (poll)
	239	rv = poll(file, pts);
	240
	241	pde_users_dec(pde);
	242	return rv;
	243	}
	244
	245	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	246	{
	247	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	248	long rv = -ENOTTY;
b19dd42f	249	long (ioctl)(struct file , unsigned int, unsigned long);
786d7e16 AD	250
	251	spin_lock(&pde->pde_unload_lock);
	252	if (!pde->proc_fops) {
	253	spin_unlock(&pde->pde_unload_lock);
	254	return rv;
	255	}
	256	pde->pde_users++;
b19dd42f	257	ioctl = pde->proc_fops->unlocked_ioctl;
786d7e16 AD	258	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	259
b19dd42f AB	260	if (ioctl)
b19dd42f AB	261	rv = ioctl(file, cmd, arg);
786d7e16 AD	262
	263	pde_users_dec(pde);
	264	return rv;
	265	}
	266
	267	#ifdef CONFIG_COMPAT
	268	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	269	{
	270	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	271	long rv = -ENOTTY;
	272	long (compat_ioctl)(struct file , unsigned int, unsigned long);
	273
	274	spin_lock(&pde->pde_unload_lock);
	275	if (!pde->proc_fops) {
	276	spin_unlock(&pde->pde_unload_lock);
	277	return rv;
	278	}
	279	pde->pde_users++;
	280	compat_ioctl = pde->proc_fops->compat_ioctl;
	281	spin_unlock(&pde->pde_unload_lock);
	282
	283	if (compat_ioctl)
	284	rv = compat_ioctl(file, cmd, arg);
	285
	286	pde_users_dec(pde);
	287	return rv;
	288	}
	289	#endif
	290
	291	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
	292	{
	293	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	294	int rv = -EIO;
	295	int (mmap)(struct file , struct vm_area_struct *);
	296
	297	spin_lock(&pde->pde_unload_lock);
	298	if (!pde->proc_fops) {
	299	spin_unlock(&pde->pde_unload_lock);
	300	return rv;
	301	}
	302	pde->pde_users++;
	303	mmap = pde->proc_fops->mmap;
	304	spin_unlock(&pde->pde_unload_lock);
	305
	306	if (mmap)
	307	rv = mmap(file, vma);
	308
	309	pde_users_dec(pde);
	310	return rv;
	311	}
	312
	313	static int proc_reg_open(struct inode inode, struct file file)
	314	{
	315	struct proc_dir_entry *pde = PDE(inode);
	316	int rv = 0;
	317	int (open)(struct inode , struct file *);
881adb85 AD	318	int (release)(struct inode , struct file *);
	319	struct pde_opener *pdeo;
	320
	321	/*
	322	* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	323	* sequence. ->release won't be called because ->proc_fops will be
	324	* cleared. Depending on complexity of ->release, consequences vary.
	325	*
	326	* We can't wait for mercy when close will be done for real, it's
	327	* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	328	* by hand in remove_proc_entry(). For this, save opener's credentials
	329	* for later.
	330	*/
	331	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	332	if (!pdeo)
	333	return -ENOMEM;
786d7e16 AD	334
	335	spin_lock(&pde->pde_unload_lock);
	336	if (!pde->proc_fops) {
	337	spin_unlock(&pde->pde_unload_lock);
881adb85	338	kfree(pdeo);
d2857e79	339	return -ENOENT;
786d7e16 AD	340	}
	341	pde->pde_users++;
	342	open = pde->proc_fops->open;
881adb85	343	release = pde->proc_fops->release;
786d7e16 AD	344	spin_unlock(&pde->pde_unload_lock);
	345
	346	if (open)
	347	rv = open(inode, file);
	348
881adb85 AD	349	spin_lock(&pde->pde_unload_lock);
	350	if (rv == 0 && release) {
	351	/* To know what to release. */
	352	pdeo->inode = inode;
	353	pdeo->file = file;
	354	/* Strictly for "too late" ->release in proc_reg_release(). */
	355	pdeo->release = release;
	356	list_add(&pdeo->lh, &pde->pde_openers);
	357	} else
	358	kfree(pdeo);
	359	__pde_users_dec(pde);
	360	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	361	return rv;
	362	}
	363
881adb85 AD	364	static struct pde_opener find_pde_opener(struct proc_dir_entry pde,
	365	struct inode inode, struct file file)
	366	{
	367	struct pde_opener *pdeo;
	368
	369	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	370	if (pdeo->inode == inode && pdeo->file == file)
	371	return pdeo;
	372	}
	373	return NULL;
	374	}
	375
786d7e16 AD	376	static int proc_reg_release(struct inode inode, struct file file)
	377	{
	378	struct proc_dir_entry *pde = PDE(inode);
	379	int rv = 0;
	380	int (release)(struct inode , struct file *);
881adb85	381	struct pde_opener *pdeo;
786d7e16 AD	382
786d7e16 AD	383	spin_lock(&pde->pde_unload_lock);
881adb85	384	pdeo = find_pde_opener(pde, inode, file);
786d7e16	385	if (!pde->proc_fops) {
881adb85 AD	386	/*
	387	* Can't simply exit, __fput() will think that everything is OK,
	388	* and move on to freeing struct file. remove_proc_entry() will
	389	* find slacker in opener's list and will try to do non-trivial
	390	* things with struct file. Therefore, remove opener from list.
	391	*
	392	* But if opener is removed from list, who will ->release it?
	393	*/
	394	if (pdeo) {
	395	list_del(&pdeo->lh);
	396	spin_unlock(&pde->pde_unload_lock);
	397	rv = pdeo->release(inode, file);
	398	kfree(pdeo);
	399	} else
	400	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	401	return rv;
	402	}
	403	pde->pde_users++;
	404	release = pde->proc_fops->release;
881adb85 AD	405	if (pdeo) {
	406	list_del(&pdeo->lh);
	407	kfree(pdeo);
	408	}
786d7e16 AD	409	spin_unlock(&pde->pde_unload_lock);
	410
	411	if (release)
	412	rv = release(inode, file);
	413
	414	pde_users_dec(pde);
	415	return rv;
	416	}
	417
	418	static const struct file_operations proc_reg_file_ops = {
	419	.llseek = proc_reg_llseek,
	420	.read = proc_reg_read,
	421	.write = proc_reg_write,
	422	.poll = proc_reg_poll,
	423	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	424	#ifdef CONFIG_COMPAT
	425	.compat_ioctl = proc_reg_compat_ioctl,
	426	#endif
	427	.mmap = proc_reg_mmap,
	428	.open = proc_reg_open,
	429	.release = proc_reg_release,
	430	};
	431
778f3dd5 DM	432	#ifdef CONFIG_COMPAT
	433	static const struct file_operations proc_reg_file_ops_no_compat = {
	434	.llseek = proc_reg_llseek,
	435	.read = proc_reg_read,
	436	.write = proc_reg_write,
	437	.poll = proc_reg_poll,
	438	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	439	.mmap = proc_reg_mmap,
	440	.open = proc_reg_open,
	441	.release = proc_reg_release,
	442	};
	443	#endif
	444
6d1b6e4e	445	struct inode proc_get_inode(struct super_block sb, struct proc_dir_entry *de)
1da177e4 LT	446	{
	447	struct inode * inode;
	448
6d1b6e4e	449	inode = iget_locked(sb, de->low_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)
bfe86848	465	set_nlink(inode, de->nlink);
5e971dce AD	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
135d5655	483	pde_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
135d5655	498	pde_get(&proc_root);
6d1b6e4e	499	root_inode = proc_get_inode(s, &proc_root);
1da177e4 LT	500	if (!root_inode)
1da177e4 LT	501	goto out_no_root;
1da177e4	502	s->s_root = d_alloc_root(root_inode);
6b4231e2 AV	503	if (!s->s_root) {
6b4231e2 AV	504	iput(root_inode);
1da177e4	505	goto out_no_root;
6b4231e2	506	}
1da177e4 LT	507	return 0;
	508
	509	out_no_root:
	510	printk("proc_read_super: get root inode failed\n");
135d5655	511	pde_put(&proc_root);
1da177e4 LT	512	return -ENOMEM;
1da177e4 LT	513	}