[GitHub/mt8127/android_kernel_alcatel_ttab.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/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;
	void *ns;

	truncate_inode_pages(&inode->i_data, 0);
	clear_inode(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;
	ns = PROC_I(inode)->ns;
	if (ns_ops && ns)
		ns_ops->put(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 (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, 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_inode(file));
	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_inode(file));
	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_inode(file));
	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_inode(file));
	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_inode(file));
	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_inode(file));
	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_inode(file));
	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)->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)
{
	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);
	s->s_root = d_make_root(proc_get_inode(s, &proc_root));
	if (s->s_root)
		return 0;

	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	24
1da177e4 LT	25	#include <asm/uaccess.h>
1da177e4 LT	26
fee781e6	27	#include "internal.h"
1da177e4	28
8267952b	29	static void proc_evict_inode(struct inode *inode)
1da177e4 LT	30	{
1da177e4 LT	31	struct proc_dir_entry *de;
dfef6dcd	32	struct ctl_table_header *head;
6b4e306a	33	const struct proc_ns_operations *ns_ops;
bf056bfa	34	void *ns;
1da177e4	35
fef26658	36	truncate_inode_pages(&inode->i_data, 0);
dbd5768f	37	clear_inode(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 */
6b4e306a EB	52	ns_ops = PROC_I(inode)->ns_ops;
bf056bfa EB	53	ns = PROC_I(inode)->ns;
	54	if (ns_ops && ns)
	55	ns_ops->put(ns);
1da177e4 LT	56	}
1da177e4 LT	57
e18b890b	58	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	59
	60	static struct inode proc_alloc_inode(struct super_block sb)
	61	{
	62	struct proc_inode *ei;
	63	struct inode *inode;
	64
e94b1766	65	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	66	if (!ei)
1da177e4 LT	67	return NULL;
13b41b09	68	ei->pid = NULL;
aed7a6c4	69	ei->fd = 0;
1da177e4 LT	70	ei->op.proc_get_link = NULL;
1da177e4 LT	71	ei->pde = NULL;
9043476f AV	72	ei->sysctl = NULL;
9043476f AV	73	ei->sysctl_entry = NULL;
6b4e306a EB	74	ei->ns = NULL;
6b4e306a EB	75	ei->ns_ops = NULL;
1da177e4 LT	76	inode = &ei->vfs_inode;
	77	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	78	return inode;
	79	}
	80
fa0d7e3d	81	static void proc_i_callback(struct rcu_head *head)
1da177e4	82	{
fa0d7e3d	83	struct inode *inode = container_of(head, struct inode, i_rcu);
1da177e4 LT	84	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	85	}
	86
fa0d7e3d NP	87	static void proc_destroy_inode(struct inode *inode)
	88	{
	89	call_rcu(&inode->i_rcu, proc_i_callback);
	90	}
	91
51cc5068	92	static void init_once(void *foo)
1da177e4 LT	93	{
	94	struct proc_inode ei = (struct proc_inode ) foo;
	95
a35afb83	96	inode_init_once(&ei->vfs_inode);
1da177e4	97	}
20c2df83	98
5bcd7ff9	99	void __init proc_init_inodecache(void)
1da177e4 LT	100	{
	101	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	102	sizeof(struct proc_inode),
fffb60f9	103	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	104	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	105	init_once);
1da177e4 LT	106	}
1da177e4 LT	107
97412950 VK	108	static int proc_show_options(struct seq_file seq, struct dentry root)
97412950 VK	109	{
0499680a VK	110	struct super_block *sb = root->d_sb;
	111	struct pid_namespace *pid = sb->s_fs_info;
	112
dcb0f222 EB	113	if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
dcb0f222 EB	114	seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
0499680a VK	115	if (pid->hide_pid != 0)
	116	seq_printf(seq, ",hidepid=%u", pid->hide_pid);
	117
97412950 VK	118	return 0;
	119	}
	120
ee9b6d61	121	static const struct super_operations proc_sops = {
1da177e4 LT	122	.alloc_inode = proc_alloc_inode,
1da177e4 LT	123	.destroy_inode = proc_destroy_inode,
1da177e4	124	.drop_inode = generic_delete_inode,
8267952b	125	.evict_inode = proc_evict_inode,
1da177e4	126	.statfs = simple_statfs,
97412950 VK	127	.remount_fs = proc_remount,
97412950 VK	128	.show_options = proc_show_options,
1da177e4 LT	129	};
1da177e4 LT	130
881adb85	131	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	132	{
786d7e16 AD	133	pde->pde_users--;
	134	if (pde->pde_unload_completion && pde->pde_users == 0)
	135	complete(pde->pde_unload_completion);
881adb85 AD	136	}
881adb85 AD	137
3dec7f59	138	void pde_users_dec(struct proc_dir_entry *pde)
881adb85 AD	139	{
	140	spin_lock(&pde->pde_unload_lock);
	141	__pde_users_dec(pde);
786d7e16 AD	142	spin_unlock(&pde->pde_unload_lock);
	143	}
	144
	145	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	146	{
496ad9aa	147	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16 AD	148	loff_t rv = -EINVAL;
	149	loff_t (llseek)(struct file , loff_t, int);
	150
	151	spin_lock(&pde->pde_unload_lock);
	152	/*
	153	* remove_proc_entry() is going to delete PDE (as part of module
	154	* cleanup sequence). No new callers into module allowed.
	155	*/
	156	if (!pde->proc_fops) {
	157	spin_unlock(&pde->pde_unload_lock);
	158	return rv;
	159	}
	160	/*
	161	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	162	* complete.
	163	*/
	164	pde->pde_users++;
	165	/*
	166	* Save function pointer under lock, to protect against ->proc_fops
	167	* NULL'ifying right after ->pde_unload_lock is dropped.
	168	*/
	169	llseek = pde->proc_fops->llseek;
	170	spin_unlock(&pde->pde_unload_lock);
	171
	172	if (!llseek)
	173	llseek = default_llseek;
	174	rv = llseek(file, offset, whence);
	175
	176	pde_users_dec(pde);
	177	return rv;
	178	}
	179
	180	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	181	{
496ad9aa	182	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16 AD	183	ssize_t rv = -EIO;
	184	ssize_t (read)(struct file , char __user , size_t, loff_t );
	185
	186	spin_lock(&pde->pde_unload_lock);
	187	if (!pde->proc_fops) {
	188	spin_unlock(&pde->pde_unload_lock);
	189	return rv;
	190	}
	191	pde->pde_users++;
	192	read = pde->proc_fops->read;
	193	spin_unlock(&pde->pde_unload_lock);
	194
	195	if (read)
	196	rv = read(file, buf, count, ppos);
	197
	198	pde_users_dec(pde);
	199	return rv;
	200	}
	201
	202	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	203	{
496ad9aa	204	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16 AD	205	ssize_t rv = -EIO;
	206	ssize_t (write)(struct file , const char __user , size_t, loff_t );
	207
	208	spin_lock(&pde->pde_unload_lock);
	209	if (!pde->proc_fops) {
	210	spin_unlock(&pde->pde_unload_lock);
	211	return rv;
	212	}
	213	pde->pde_users++;
	214	write = pde->proc_fops->write;
	215	spin_unlock(&pde->pde_unload_lock);
	216
	217	if (write)
	218	rv = write(file, buf, count, ppos);
	219
	220	pde_users_dec(pde);
	221	return rv;
	222	}
	223
	224	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
	225	{
496ad9aa	226	struct proc_dir_entry *pde = PDE(file_inode(file));
dd23aae4	227	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	228	unsigned int (poll)(struct file , struct poll_table_struct *);
	229
	230	spin_lock(&pde->pde_unload_lock);
	231	if (!pde->proc_fops) {
	232	spin_unlock(&pde->pde_unload_lock);
	233	return rv;
	234	}
	235	pde->pde_users++;
	236	poll = pde->proc_fops->poll;
	237	spin_unlock(&pde->pde_unload_lock);
	238
	239	if (poll)
	240	rv = poll(file, pts);
	241
	242	pde_users_dec(pde);
	243	return rv;
	244	}
	245
	246	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	247	{
496ad9aa	248	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16	249	long rv = -ENOTTY;
b19dd42f	250	long (ioctl)(struct file , unsigned int, unsigned long);
786d7e16 AD	251
	252	spin_lock(&pde->pde_unload_lock);
	253	if (!pde->proc_fops) {
	254	spin_unlock(&pde->pde_unload_lock);
	255	return rv;
	256	}
	257	pde->pde_users++;
b19dd42f	258	ioctl = pde->proc_fops->unlocked_ioctl;
786d7e16 AD	259	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	260
b19dd42f AB	261	if (ioctl)
b19dd42f AB	262	rv = ioctl(file, cmd, arg);
786d7e16 AD	263
	264	pde_users_dec(pde);
	265	return rv;
	266	}
	267
	268	#ifdef CONFIG_COMPAT
	269	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	270	{
496ad9aa	271	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16 AD	272	long rv = -ENOTTY;
	273	long (compat_ioctl)(struct file , unsigned int, unsigned long);
	274
	275	spin_lock(&pde->pde_unload_lock);
	276	if (!pde->proc_fops) {
	277	spin_unlock(&pde->pde_unload_lock);
	278	return rv;
	279	}
	280	pde->pde_users++;
	281	compat_ioctl = pde->proc_fops->compat_ioctl;
	282	spin_unlock(&pde->pde_unload_lock);
	283
	284	if (compat_ioctl)
	285	rv = compat_ioctl(file, cmd, arg);
	286
	287	pde_users_dec(pde);
	288	return rv;
	289	}
	290	#endif
	291
	292	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
	293	{
496ad9aa	294	struct proc_dir_entry *pde = PDE(file_inode(file));
786d7e16 AD	295	int rv = -EIO;
	296	int (mmap)(struct file , struct vm_area_struct *);
	297
	298	spin_lock(&pde->pde_unload_lock);
	299	if (!pde->proc_fops) {
	300	spin_unlock(&pde->pde_unload_lock);
	301	return rv;
	302	}
	303	pde->pde_users++;
	304	mmap = pde->proc_fops->mmap;
	305	spin_unlock(&pde->pde_unload_lock);
	306
	307	if (mmap)
	308	rv = mmap(file, vma);
	309
	310	pde_users_dec(pde);
	311	return rv;
	312	}
	313
	314	static int proc_reg_open(struct inode inode, struct file file)
	315	{
	316	struct proc_dir_entry *pde = PDE(inode);
	317	int rv = 0;
	318	int (open)(struct inode , struct file *);
881adb85 AD	319	int (release)(struct inode , struct file *);
	320	struct pde_opener *pdeo;
	321
	322	/*
	323	* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
	324	* sequence. ->release won't be called because ->proc_fops will be
	325	* cleared. Depending on complexity of ->release, consequences vary.
	326	*
	327	* We can't wait for mercy when close will be done for real, it's
	328	* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
	329	* by hand in remove_proc_entry(). For this, save opener's credentials
	330	* for later.
	331	*/
	332	pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
	333	if (!pdeo)
	334	return -ENOMEM;
786d7e16 AD	335
	336	spin_lock(&pde->pde_unload_lock);
	337	if (!pde->proc_fops) {
	338	spin_unlock(&pde->pde_unload_lock);
881adb85	339	kfree(pdeo);
d2857e79	340	return -ENOENT;
786d7e16 AD	341	}
	342	pde->pde_users++;
	343	open = pde->proc_fops->open;
881adb85	344	release = pde->proc_fops->release;
786d7e16 AD	345	spin_unlock(&pde->pde_unload_lock);
	346
	347	if (open)
	348	rv = open(inode, file);
	349
881adb85 AD	350	spin_lock(&pde->pde_unload_lock);
	351	if (rv == 0 && release) {
	352	/* To know what to release. */
	353	pdeo->inode = inode;
	354	pdeo->file = file;
	355	/* Strictly for "too late" ->release in proc_reg_release(). */
	356	pdeo->release = release;
	357	list_add(&pdeo->lh, &pde->pde_openers);
	358	} else
	359	kfree(pdeo);
	360	__pde_users_dec(pde);
	361	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	362	return rv;
	363	}
	364
881adb85 AD	365	static struct pde_opener find_pde_opener(struct proc_dir_entry pde,
	366	struct inode inode, struct file file)
	367	{
	368	struct pde_opener *pdeo;
	369
	370	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
	371	if (pdeo->inode == inode && pdeo->file == file)
	372	return pdeo;
	373	}
	374	return NULL;
	375	}
	376
786d7e16 AD	377	static int proc_reg_release(struct inode inode, struct file file)
	378	{
	379	struct proc_dir_entry *pde = PDE(inode);
	380	int rv = 0;
	381	int (release)(struct inode , struct file *);
881adb85	382	struct pde_opener *pdeo;
786d7e16 AD	383
786d7e16 AD	384	spin_lock(&pde->pde_unload_lock);
881adb85	385	pdeo = find_pde_opener(pde, inode, file);
786d7e16	386	if (!pde->proc_fops) {
881adb85 AD	387	/*
	388	* Can't simply exit, __fput() will think that everything is OK,
	389	* and move on to freeing struct file. remove_proc_entry() will
	390	* find slacker in opener's list and will try to do non-trivial
	391	* things with struct file. Therefore, remove opener from list.
	392	*
	393	* But if opener is removed from list, who will ->release it?
	394	*/
	395	if (pdeo) {
	396	list_del(&pdeo->lh);
	397	spin_unlock(&pde->pde_unload_lock);
	398	rv = pdeo->release(inode, file);
	399	kfree(pdeo);
	400	} else
	401	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	402	return rv;
	403	}
	404	pde->pde_users++;
	405	release = pde->proc_fops->release;
881adb85 AD	406	if (pdeo) {
	407	list_del(&pdeo->lh);
	408	kfree(pdeo);
	409	}
786d7e16 AD	410	spin_unlock(&pde->pde_unload_lock);
	411
	412	if (release)
	413	rv = release(inode, file);
	414
	415	pde_users_dec(pde);
	416	return rv;
	417	}
	418
	419	static const struct file_operations proc_reg_file_ops = {
	420	.llseek = proc_reg_llseek,
	421	.read = proc_reg_read,
	422	.write = proc_reg_write,
	423	.poll = proc_reg_poll,
	424	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	425	#ifdef CONFIG_COMPAT
	426	.compat_ioctl = proc_reg_compat_ioctl,
	427	#endif
	428	.mmap = proc_reg_mmap,
	429	.open = proc_reg_open,
	430	.release = proc_reg_release,
	431	};
	432
778f3dd5 DM	433	#ifdef CONFIG_COMPAT
	434	static const struct file_operations proc_reg_file_ops_no_compat = {
	435	.llseek = proc_reg_llseek,
	436	.read = proc_reg_read,
	437	.write = proc_reg_write,
	438	.poll = proc_reg_poll,
	439	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	440	.mmap = proc_reg_mmap,
	441	.open = proc_reg_open,
	442	.release = proc_reg_release,
	443	};
	444	#endif
	445
6d1b6e4e	446	struct inode proc_get_inode(struct super_block sb, struct proc_dir_entry *de)
1da177e4 LT	447	{
	448	struct inode * inode;
	449
6d1b6e4e	450	inode = iget_locked(sb, de->low_ino);
1da177e4	451	if (!inode)
99b76233	452	return NULL;
a1d4aebb DH	453	if (inode->i_state & I_NEW) {
a1d4aebb DH	454	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
a1d4aebb	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	488	{
92d03285	489	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
1da177e4 LT	490	s->s_blocksize = 1024;
	491	s->s_blocksize_bits = 10;
	492	s->s_magic = PROC_SUPER_MAGIC;
	493	s->s_op = &proc_sops;
	494	s->s_time_gran = 1;
	495
135d5655	496	pde_get(&proc_root);
48fde701 AV	497	s->s_root = d_make_root(proc_get_inode(s, &proc_root));
	498	if (s->s_root)
	499	return 0;
1da177e4	500
1da177e4	501	printk("proc_read_super: get root inode failed\n");
135d5655	502	pde_put(&proc_root);
1da177e4 LT	503	return -ENOMEM;
1da177e4 LT	504	}