[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/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)
{
	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;
1da177e4	34
fef26658	35	truncate_inode_pages(&inode->i_data, 0);
8267952b	36	end_writeback(inode);
fef26658	37
99f89551	38	/* Stop tracking associated processes */
13b41b09	39	put_pid(PROC_I(inode)->pid);
1da177e4 LT	40
	41	/* Let go of any associated proc directory entry */
	42	de = PROC_I(inode)->pde;
99b76233	43	if (de)
135d5655	44	pde_put(de);
dfef6dcd AV	45	head = PROC_I(inode)->sysctl;
	46	if (head) {
	47	rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);
	48	sysctl_head_put(head);
	49	}
6b4e306a EB	50	/* Release any associated namespace */
	51	ns_ops = PROC_I(inode)->ns_ops;
	52	if (ns_ops && ns_ops->put)
	53	ns_ops->put(PROC_I(inode)->ns);
1da177e4 LT	54	}
1da177e4 LT	55
e18b890b	56	static struct kmem_cache * proc_inode_cachep;
1da177e4 LT	57
	58	static struct inode proc_alloc_inode(struct super_block sb)
	59	{
	60	struct proc_inode *ei;
	61	struct inode *inode;
	62
e94b1766	63	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
1da177e4 LT	64	if (!ei)
1da177e4 LT	65	return NULL;
13b41b09	66	ei->pid = NULL;
aed7a6c4	67	ei->fd = 0;
1da177e4 LT	68	ei->op.proc_get_link = NULL;
1da177e4 LT	69	ei->pde = NULL;
9043476f AV	70	ei->sysctl = NULL;
9043476f AV	71	ei->sysctl_entry = NULL;
6b4e306a EB	72	ei->ns = NULL;
6b4e306a EB	73	ei->ns_ops = NULL;
1da177e4 LT	74	inode = &ei->vfs_inode;
	75	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	76	return inode;
	77	}
	78
fa0d7e3d	79	static void proc_i_callback(struct rcu_head *head)
1da177e4	80	{
fa0d7e3d	81	struct inode *inode = container_of(head, struct inode, i_rcu);
1da177e4 LT	82	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	83	}
	84
fa0d7e3d NP	85	static void proc_destroy_inode(struct inode *inode)
	86	{
	87	call_rcu(&inode->i_rcu, proc_i_callback);
	88	}
	89
51cc5068	90	static void init_once(void *foo)
1da177e4 LT	91	{
	92	struct proc_inode ei = (struct proc_inode ) foo;
	93
a35afb83	94	inode_init_once(&ei->vfs_inode);
1da177e4	95	}
20c2df83	96
5bcd7ff9	97	void __init proc_init_inodecache(void)
1da177e4 LT	98	{
	99	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	100	sizeof(struct proc_inode),
fffb60f9	101	0, (SLAB_RECLAIM_ACCOUNT\|
040b5c6f	102	SLAB_MEM_SPREAD\|SLAB_PANIC),
20c2df83	103	init_once);
1da177e4 LT	104	}
1da177e4 LT	105
97412950 VK	106	static int proc_show_options(struct seq_file seq, struct dentry root)
97412950 VK	107	{
0499680a VK	108	struct super_block *sb = root->d_sb;
	109	struct pid_namespace *pid = sb->s_fs_info;
	110
	111	if (pid->pid_gid)
	112	seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid);
	113	if (pid->hide_pid != 0)
	114	seq_printf(seq, ",hidepid=%u", pid->hide_pid);
	115
97412950 VK	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	122	.drop_inode = generic_delete_inode,
8267952b	123	.evict_inode = proc_evict_inode,
1da177e4	124	.statfs = simple_statfs,
97412950 VK	125	.remount_fs = proc_remount,
97412950 VK	126	.show_options = proc_show_options,
1da177e4 LT	127	};
1da177e4 LT	128
881adb85	129	static void __pde_users_dec(struct proc_dir_entry *pde)
786d7e16	130	{
786d7e16 AD	131	pde->pde_users--;
	132	if (pde->pde_unload_completion && pde->pde_users == 0)
	133	complete(pde->pde_unload_completion);
881adb85 AD	134	}
881adb85 AD	135
3dec7f59	136	void pde_users_dec(struct proc_dir_entry *pde)
881adb85 AD	137	{
	138	spin_lock(&pde->pde_unload_lock);
	139	__pde_users_dec(pde);
786d7e16 AD	140	spin_unlock(&pde->pde_unload_lock);
	141	}
	142
	143	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	144	{
	145	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	146	loff_t rv = -EINVAL;
	147	loff_t (llseek)(struct file , loff_t, int);
	148
	149	spin_lock(&pde->pde_unload_lock);
	150	/*
	151	* remove_proc_entry() is going to delete PDE (as part of module
	152	* cleanup sequence). No new callers into module allowed.
	153	*/
	154	if (!pde->proc_fops) {
	155	spin_unlock(&pde->pde_unload_lock);
	156	return rv;
	157	}
	158	/*
	159	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	160	* complete.
	161	*/
	162	pde->pde_users++;
	163	/*
	164	* Save function pointer under lock, to protect against ->proc_fops
	165	* NULL'ifying right after ->pde_unload_lock is dropped.
	166	*/
	167	llseek = pde->proc_fops->llseek;
	168	spin_unlock(&pde->pde_unload_lock);
	169
	170	if (!llseek)
	171	llseek = default_llseek;
	172	rv = llseek(file, offset, whence);
	173
	174	pde_users_dec(pde);
	175	return rv;
	176	}
	177
	178	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	179	{
	180	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	181	ssize_t rv = -EIO;
	182	ssize_t (read)(struct file , char __user , size_t, loff_t );
	183
	184	spin_lock(&pde->pde_unload_lock);
	185	if (!pde->proc_fops) {
	186	spin_unlock(&pde->pde_unload_lock);
	187	return rv;
	188	}
	189	pde->pde_users++;
	190	read = pde->proc_fops->read;
	191	spin_unlock(&pde->pde_unload_lock);
	192
	193	if (read)
	194	rv = read(file, buf, count, ppos);
	195
	196	pde_users_dec(pde);
	197	return rv;
	198	}
	199
	200	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	201	{
	202	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	203	ssize_t rv = -EIO;
204	ssize_t (write)(struct file , const char __user , size_t, loff_t );
205
206	spin_lock(&pde->pde_unload_lock);
207	if (!pde->proc_fops) {
208	spin_unlock(&pde->pde_unload_lock);
209	return rv;
210	}
211	pde->pde_users++;
212	write = pde->proc_fops->write;
213	spin_unlock(&pde->pde_unload_lock);
214
215	if (write)
216	rv = write(file, buf, count, ppos);
217
218	pde_users_dec(pde);
219	return rv;
220	}
221
222	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
223	{
224	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
dd23aae4	225	unsigned int rv = DEFAULT_POLLMASK;
786d7e16 AD	226	unsigned int (poll)(struct file , struct poll_table_struct *);
	227
	228	spin_lock(&pde->pde_unload_lock);
	229	if (!pde->proc_fops) {
	230	spin_unlock(&pde->pde_unload_lock);
	231	return rv;
	232	}
	233	pde->pde_users++;
	234	poll = pde->proc_fops->poll;
	235	spin_unlock(&pde->pde_unload_lock);
	236
	237	if (poll)
	238	rv = poll(file, pts);
	239
	240	pde_users_dec(pde);
	241	return rv;
	242	}
	243
	244	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	245	{
	246	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	247	long rv = -ENOTTY;
b19dd42f	248	long (ioctl)(struct file , unsigned int, unsigned long);
786d7e16 AD	249
	250	spin_lock(&pde->pde_unload_lock);
	251	if (!pde->proc_fops) {
	252	spin_unlock(&pde->pde_unload_lock);
	253	return rv;
	254	}
	255	pde->pde_users++;
b19dd42f	256	ioctl = pde->proc_fops->unlocked_ioctl;
786d7e16 AD	257	spin_unlock(&pde->pde_unload_lock);
786d7e16 AD	258
b19dd42f AB	259	if (ioctl)
b19dd42f AB	260	rv = ioctl(file, cmd, arg);
786d7e16 AD	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);
d2857e79	338	return -ENOENT;
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
6d1b6e4e	444	struct inode proc_get_inode(struct super_block sb, struct proc_dir_entry *de)
1da177e4 LT	445	{
	446	struct inode * inode;
	447
6d1b6e4e	448	inode = iget_locked(sb, de->low_ino);
1da177e4	449	if (!inode)
99b76233	450	return NULL;
a1d4aebb DH	451	if (inode->i_state & I_NEW) {
	452	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	453	PROC_I(inode)->fd = 0;
	454	PROC_I(inode)->pde = de;
5e971dce AD	455
	456	if (de->mode) {
	457	inode->i_mode = de->mode;
	458	inode->i_uid = de->uid;
	459	inode->i_gid = de->gid;
	460	}
	461	if (de->size)
	462	inode->i_size = de->size;
	463	if (de->nlink)
bfe86848	464	set_nlink(inode, de->nlink);
5e971dce AD	465	if (de->proc_iops)
	466	inode->i_op = de->proc_iops;
	467	if (de->proc_fops) {
	468	if (S_ISREG(inode->i_mode)) {
778f3dd5	469	#ifdef CONFIG_COMPAT
5e971dce AD	470	if (!de->proc_fops->compat_ioctl)
	471	inode->i_fop =
	472	&proc_reg_file_ops_no_compat;
	473	else
778f3dd5	474	#endif
5e971dce AD	475	inode->i_fop = &proc_reg_file_ops;
	476	} else {
	477	inode->i_fop = de->proc_fops;
778f3dd5	478	}
786d7e16	479	}
a1d4aebb	480	unlock_new_inode(inode);
99b76233	481	} else
135d5655	482	pde_put(de);
1da177e4	483	return inode;
1da177e4 LT	484	}
1da177e4 LT	485
07543f5c	486	int proc_fill_super(struct super_block *s)
1da177e4	487	{
92d03285	488	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
1da177e4 LT	489	s->s_blocksize = 1024;
	490	s->s_blocksize_bits = 10;
	491	s->s_magic = PROC_SUPER_MAGIC;
	492	s->s_op = &proc_sops;
	493	s->s_time_gran = 1;
	494
135d5655	495	pde_get(&proc_root);
48fde701 AV	496	s->s_root = d_make_root(proc_get_inode(s, &proc_root));
	497	if (s->s_root)
	498	return 0;
1da177e4	499
1da177e4	500	printk("proc_read_super: get root inode failed\n");
135d5655	501	pde_put(&proc_root);
1da177e4 LT	502	return -ENOMEM;
1da177e4 LT	503	}