[net-next-2.6.git] / fs / proc / proc_sysctl.c

/*
 * /proc/sys support
 */
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include "internal.h"

static const struct dentry_operations proc_sys_dentry_operations;
static const struct file_operations proc_sys_file_operations;
static const struct inode_operations proc_sys_inode_operations;
static const struct file_operations proc_sys_dir_file_operations;
static const struct inode_operations proc_sys_dir_operations;

static struct inode *proc_sys_make_inode(struct super_block *sb,
		struct ctl_table_header *head, struct ctl_table *table)
{
	struct inode *inode;
	struct proc_inode *ei;

	inode = new_inode(sb);
	if (!inode)
		goto out;

	sysctl_head_get(head);
	ei = PROC_I(inode);
	ei->sysctl = head;
	ei->sysctl_entry = table;

	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	inode->i_flags |= S_PRIVATE; /* tell selinux to ignore this inode */
	inode->i_mode = table->mode;
	if (!table->child) {
		inode->i_mode |= S_IFREG;
		inode->i_op = &proc_sys_inode_operations;
		inode->i_fop = &proc_sys_file_operations;
	} else {
		inode->i_mode |= S_IFDIR;
		inode->i_nlink = 0;
		inode->i_op = &proc_sys_dir_operations;
		inode->i_fop = &proc_sys_dir_file_operations;
	}
out:
	return inode;
}

static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
{
	int len;
	for ( ; p->ctl_name || p->procname; p++) {

		if (!p->procname)
			continue;

		len = strlen(p->procname);
		if (len != name->len)
			continue;

		if (memcmp(p->procname, name->name, len) != 0)
			continue;

		/* I have a match */
		return p;
	}
	return NULL;
}

static struct ctl_table_header *grab_header(struct inode *inode)
{
	if (PROC_I(inode)->sysctl)
		return sysctl_head_grab(PROC_I(inode)->sysctl);
	else
		return sysctl_head_next(NULL);
}

static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
					struct nameidata *nd)
{
	struct ctl_table_header *head = grab_header(dir);
	struct ctl_table *table = PROC_I(dir)->sysctl_entry;
	struct ctl_table_header *h = NULL;
	struct qstr *name = &dentry->d_name;
	struct ctl_table *p;
	struct inode *inode;
	struct dentry *err = ERR_PTR(-ENOENT);

	if (IS_ERR(head))
		return ERR_CAST(head);

	if (table && !table->child) {
		WARN_ON(1);
		goto out;
	}

	table = table ? table->child : head->ctl_table;

	p = find_in_table(table, name);
	if (!p) {
		for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
			if (h->attached_to != table)
				continue;
			p = find_in_table(h->attached_by, name);
			if (p)
				break;
		}
	}

	if (!p)
		goto out;

	err = ERR_PTR(-ENOMEM);
	inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
	if (h)
		sysctl_head_finish(h);

	if (!inode)
		goto out;

	err = NULL;
	dentry->d_op = &proc_sys_dentry_operations;
	d_add(dentry, inode);

out:
	sysctl_head_finish(head);
	return err;
}

static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
		size_t count, loff_t *ppos, int write)
{
	struct inode *inode = filp->f_path.dentry->d_inode;
	struct ctl_table_header *head = grab_header(inode);
	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
	ssize_t error;
	size_t res;

	if (IS_ERR(head))
		return PTR_ERR(head);

	/*
	 * At this point we know that the sysctl was not unregistered
	 * and won't be until we finish.
	 */
	error = -EPERM;
	if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
		goto out;

	/* if that can happen at all, it should be -EINVAL, not -EISDIR */
	error = -EINVAL;
	if (!table->proc_handler)
		goto out;

	/* careful: calling conventions are nasty here */
	res = count;
	error = table->proc_handler(table, write, buf, &res, ppos);
	if (!error)
		error = res;
out:
	sysctl_head_finish(head);

	return error;
}

static ssize_t proc_sys_read(struct file *filp, char __user *buf,
				size_t count, loff_t *ppos)
{
	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
}

static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
				size_t count, loff_t *ppos)
{
	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
}


static int proc_sys_fill_cache(struct file *filp, void *dirent,
				filldir_t filldir,
				struct ctl_table_header *head,
				struct ctl_table *table)
{
	struct dentry *child, *dir = filp->f_path.dentry;
	struct inode *inode;
	struct qstr qname;
	ino_t ino = 0;
	unsigned type = DT_UNKNOWN;

	qname.name = table->procname;
	qname.len  = strlen(table->procname);
	qname.hash = full_name_hash(qname.name, qname.len);

	child = d_lookup(dir, &qname);
	if (!child) {
		child = d_alloc(dir, &qname);
		if (child) {
			inode = proc_sys_make_inode(dir->d_sb, head, table);
			if (!inode) {
				dput(child);
				return -ENOMEM;
			} else {
				child->d_op = &proc_sys_dentry_operations;
				d_add(child, inode);
			}
		} else {
			return -ENOMEM;
		}
	}
	inode = child->d_inode;
	ino  = inode->i_ino;
	type = inode->i_mode >> 12;
	dput(child);
	return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
}

static int scan(struct ctl_table_header *head, ctl_table *table,
		unsigned long *pos, struct file *file,
		void *dirent, filldir_t filldir)
{

	for (; table->ctl_name || table->procname; table++, (*pos)++) {
		int res;

		/* Can't do anything without a proc name */
		if (!table->procname)
			continue;

		if (*pos < file->f_pos)
			continue;

		res = proc_sys_fill_cache(file, dirent, filldir, head, table);
		if (res)
			return res;

		file->f_pos = *pos + 1;
	}
	return 0;
}

static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
	struct dentry *dentry = filp->f_path.dentry;
	struct inode *inode = dentry->d_inode;
	struct ctl_table_header *head = grab_header(inode);
	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
	struct ctl_table_header *h = NULL;
	unsigned long pos;
	int ret = -EINVAL;

	if (IS_ERR(head))
		return PTR_ERR(head);

	if (table && !table->child) {
		WARN_ON(1);
		goto out;
	}

	table = table ? table->child : head->ctl_table;

	ret = 0;
	/* Avoid a switch here: arm builds fail with missing __cmpdi2 */
	if (filp->f_pos == 0) {
		if (filldir(dirent, ".", 1, filp->f_pos,
				inode->i_ino, DT_DIR) < 0)
			goto out;
		filp->f_pos++;
	}
	if (filp->f_pos == 1) {
		if (filldir(dirent, "..", 2, filp->f_pos,
				parent_ino(dentry), DT_DIR) < 0)
			goto out;
		filp->f_pos++;
	}
	pos = 2;

	ret = scan(head, table, &pos, filp, dirent, filldir);
	if (ret)
		goto out;

	for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
		if (h->attached_to != table)
			continue;
		ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
		if (ret) {
			sysctl_head_finish(h);
			break;
		}
	}
	ret = 1;
out:
	sysctl_head_finish(head);
	return ret;
}

static int proc_sys_permission(struct inode *inode, int mask)
{
	/*
	 * sysctl entries that are not writeable,
	 * are _NOT_ writeable, capabilities or not.
	 */
	struct ctl_table_header *head;
	struct ctl_table *table;
	int error;

	/* Executable files are not allowed under /proc/sys/ */
	if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
		return -EACCES;

	head = grab_header(inode);
	if (IS_ERR(head))
		return PTR_ERR(head);

	table = PROC_I(inode)->sysctl_entry;
	if (!table) /* global root - r-xr-xr-x */
		error = mask & MAY_WRITE ? -EACCES : 0;
	else /* Use the permissions on the sysctl table entry */
		error = sysctl_perm(head->root, table, mask);

	sysctl_head_finish(head);
	return error;
}

static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
{
	struct inode *inode = dentry->d_inode;
	int error;

	if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
		return -EPERM;

	error = inode_change_ok(inode, attr);
	if (!error)
		error = inode_setattr(inode, attr);

	return error;
}

static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
	struct inode *inode = dentry->d_inode;
	struct ctl_table_header *head = grab_header(inode);
	struct ctl_table *table = PROC_I(inode)->sysctl_entry;

	if (IS_ERR(head))
		return PTR_ERR(head);

	generic_fillattr(inode, stat);
	if (table)
		stat->mode = (stat->mode & S_IFMT) | table->mode;

	sysctl_head_finish(head);
	return 0;
}

static const struct file_operations proc_sys_file_operations = {
	.read		= proc_sys_read,
	.write		= proc_sys_write,
};

static const struct file_operations proc_sys_dir_file_operations = {
	.readdir	= proc_sys_readdir,
	.llseek		= generic_file_llseek,
};

static const struct inode_operations proc_sys_inode_operations = {
	.permission	= proc_sys_permission,
	.setattr	= proc_sys_setattr,
	.getattr	= proc_sys_getattr,
};

static const struct inode_operations proc_sys_dir_operations = {
	.lookup		= proc_sys_lookup,
	.permission	= proc_sys_permission,
	.setattr	= proc_sys_setattr,
	.getattr	= proc_sys_getattr,
};

static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
{
	return !PROC_I(dentry->d_inode)->sysctl->unregistering;
}

static int proc_sys_delete(struct dentry *dentry)
{
	return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
}

static int proc_sys_compare(struct dentry *dir, struct qstr *qstr,
			    struct qstr *name)
{
	struct dentry *dentry = container_of(qstr, struct dentry, d_name);
	if (qstr->len != name->len)
		return 1;
	if (memcmp(qstr->name, name->name, name->len))
		return 1;
	return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl);
}

static const struct dentry_operations proc_sys_dentry_operations = {
	.d_revalidate	= proc_sys_revalidate,
	.d_delete	= proc_sys_delete,
	.d_compare	= proc_sys_compare,
};

int __init proc_sys_init(void)
{
	struct proc_dir_entry *proc_sys_root;

	proc_sys_root = proc_mkdir("sys", NULL);
	proc_sys_root->proc_iops = &proc_sys_dir_operations;
	proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
	proc_sys_root->nlink = 0;
	return 0;
}
Commit	Line	Data
77b14db5 EB	1	/*
	2	* /proc/sys support
	3	*/
1e0edd3f	4	#include <linux/init.h>
77b14db5 EB	5	#include <linux/sysctl.h>
	6	#include <linux/proc_fs.h>
	7	#include <linux/security.h>
	8	#include "internal.h"
	9
d72f71eb	10	static const struct dentry_operations proc_sys_dentry_operations;
77b14db5	11	static const struct file_operations proc_sys_file_operations;
03a44825	12	static const struct inode_operations proc_sys_inode_operations;
9043476f AV	13	static const struct file_operations proc_sys_dir_file_operations;
9043476f AV	14	static const struct inode_operations proc_sys_dir_operations;
77b14db5	15
9043476f AV	16	static struct inode proc_sys_make_inode(struct super_block sb,
9043476f AV	17	struct ctl_table_header head, struct ctl_table table)
77b14db5 EB	18	{
77b14db5 EB	19	struct inode *inode;
9043476f	20	struct proc_inode *ei;
77b14db5	21
9043476f	22	inode = new_inode(sb);
77b14db5 EB	23	if (!inode)
	24	goto out;
	25
9043476f	26	sysctl_head_get(head);
77b14db5	27	ei = PROC_I(inode);
9043476f AV	28	ei->sysctl = head;
	29	ei->sysctl_entry = table;
	30
77b14db5	31	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
86a71dbd	32	inode->i_flags \|= S_PRIVATE; /* tell selinux to ignore this inode */
9043476f AV	33	inode->i_mode = table->mode;
	34	if (!table->child) {
	35	inode->i_mode \|= S_IFREG;
	36	inode->i_op = &proc_sys_inode_operations;
	37	inode->i_fop = &proc_sys_file_operations;
	38	} else {
	39	inode->i_mode \|= S_IFDIR;
	40	inode->i_nlink = 0;
	41	inode->i_op = &proc_sys_dir_operations;
	42	inode->i_fop = &proc_sys_dir_file_operations;
	43	}
77b14db5 EB	44	out:
	45	return inode;
	46	}
	47
9043476f	48	static struct ctl_table find_in_table(struct ctl_table p, struct qstr *name)
77b14db5 EB	49	{
77b14db5 EB	50	int len;
9043476f	51	for ( ; p->ctl_name \|\| p->procname; p++) {
77b14db5	52
9043476f	53	if (!p->procname)
77b14db5 EB	54	continue;
77b14db5 EB	55
9043476f	56	len = strlen(p->procname);
77b14db5 EB	57	if (len != name->len)
	58	continue;
	59
9043476f	60	if (memcmp(p->procname, name->name, len) != 0)
77b14db5 EB	61	continue;
	62
	63	/* I have a match */
9043476f	64	return p;
77b14db5 EB	65	}
	66	return NULL;
	67	}
	68
81324364	69	static struct ctl_table_header grab_header(struct inode inode)
77b14db5	70	{
9043476f AV	71	if (PROC_I(inode)->sysctl)
	72	return sysctl_head_grab(PROC_I(inode)->sysctl);
	73	else
	74	return sysctl_head_next(NULL);
	75	}
77b14db5	76
9043476f AV	77	static struct dentry proc_sys_lookup(struct inode dir, struct dentry *dentry,
	78	struct nameidata *nd)
	79	{
	80	struct ctl_table_header *head = grab_header(dir);
	81	struct ctl_table *table = PROC_I(dir)->sysctl_entry;
	82	struct ctl_table_header *h = NULL;
	83	struct qstr *name = &dentry->d_name;
	84	struct ctl_table *p;
	85	struct inode *inode;
	86	struct dentry *err = ERR_PTR(-ENOENT);
77b14db5	87
9043476f AV	88	if (IS_ERR(head))
9043476f AV	89	return ERR_CAST(head);
77b14db5	90
9043476f AV	91	if (table && !table->child) {
	92	WARN_ON(1);
	93	goto out;
77b14db5	94	}
77b14db5	95
9043476f	96	table = table ? table->child : head->ctl_table;
77b14db5	97
9043476f AV	98	p = find_in_table(table, name);
	99	if (!p) {
	100	for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
	101	if (h->attached_to != table)
	102	continue;
	103	p = find_in_table(h->attached_by, name);
	104	if (p)
	105	break;
	106	}
77b14db5	107	}
77b14db5	108
9043476f	109	if (!p)
77b14db5 EB	110	goto out;
	111
	112	err = ERR_PTR(-ENOMEM);
9043476f AV	113	inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
	114	if (h)
	115	sysctl_head_finish(h);
	116
77b14db5 EB	117	if (!inode)
	118	goto out;
	119
	120	err = NULL;
	121	dentry->d_op = &proc_sys_dentry_operations;
	122	d_add(dentry, inode);
	123
	124	out:
	125	sysctl_head_finish(head);
	126	return err;
	127	}
	128
7708bfb1 PE	129	static ssize_t proc_sys_call_handler(struct file filp, void __user buf,
7708bfb1 PE	130	size_t count, loff_t *ppos, int write)
77b14db5	131	{
9043476f AV	132	struct inode *inode = filp->f_path.dentry->d_inode;
	133	struct ctl_table_header *head = grab_header(inode);
	134	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
2a2da53b DH	135	ssize_t error;
2a2da53b DH	136	size_t res;
77b14db5	137
9043476f AV	138	if (IS_ERR(head))
9043476f AV	139	return PTR_ERR(head);
77b14db5 EB	140
	141	/*
	142	* At this point we know that the sysctl was not unregistered
	143	* and won't be until we finish.
	144	*/
	145	error = -EPERM;
d7321cd6	146	if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
77b14db5 EB	147	goto out;
77b14db5 EB	148
9043476f AV	149	/* if that can happen at all, it should be -EINVAL, not -EISDIR */
	150	error = -EINVAL;
	151	if (!table->proc_handler)
	152	goto out;
	153
77b14db5 EB	154	/* careful: calling conventions are nasty here */
77b14db5 EB	155	res = count;
8d65af78	156	error = table->proc_handler(table, write, buf, &res, ppos);
77b14db5 EB	157	if (!error)
	158	error = res;
	159	out:
	160	sysctl_head_finish(head);
	161
	162	return error;
	163	}
	164
7708bfb1	165	static ssize_t proc_sys_read(struct file filp, char __user buf,
77b14db5 EB	166	size_t count, loff_t *ppos)
77b14db5 EB	167	{
7708bfb1 PE	168	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
7708bfb1 PE	169	}
77b14db5	170
7708bfb1 PE	171	static ssize_t proc_sys_write(struct file filp, const char __user buf,
	172	size_t count, loff_t *ppos)
	173	{
	174	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
77b14db5 EB	175	}
	176
	177
	178	static int proc_sys_fill_cache(struct file filp, void dirent,
9043476f AV	179	filldir_t filldir,
	180	struct ctl_table_header *head,
	181	struct ctl_table *table)
77b14db5	182	{
77b14db5 EB	183	struct dentry child, dir = filp->f_path.dentry;
	184	struct inode *inode;
	185	struct qstr qname;
	186	ino_t ino = 0;
	187	unsigned type = DT_UNKNOWN;
77b14db5 EB	188
	189	qname.name = table->procname;
	190	qname.len = strlen(table->procname);
	191	qname.hash = full_name_hash(qname.name, qname.len);
	192
77b14db5 EB	193	child = d_lookup(dir, &qname);
77b14db5 EB	194	if (!child) {
9043476f AV	195	child = d_alloc(dir, &qname);
	196	if (child) {
	197	inode = proc_sys_make_inode(dir->d_sb, head, table);
	198	if (!inode) {
	199	dput(child);
	200	return -ENOMEM;
	201	} else {
	202	child->d_op = &proc_sys_dentry_operations;
	203	d_add(child, inode);
77b14db5	204	}
9043476f AV	205	} else {
9043476f AV	206	return -ENOMEM;
77b14db5 EB	207	}
77b14db5 EB	208	}
77b14db5	209	inode = child->d_inode;
9043476f AV	210	ino = inode->i_ino;
9043476f AV	211	type = inode->i_mode >> 12;
77b14db5	212	dput(child);
9043476f AV	213	return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
	214	}
	215
	216	static int scan(struct ctl_table_header head, ctl_table table,
	217	unsigned long pos, struct file file,
	218	void *dirent, filldir_t filldir)
	219	{
	220
	221	for (; table->ctl_name \|\| table->procname; table++, (*pos)++) {
	222	int res;
	223
	224	/* Can't do anything without a proc name */
	225	if (!table->procname)
	226	continue;
	227
	228	if (*pos < file->f_pos)
	229	continue;
	230
	231	res = proc_sys_fill_cache(file, dirent, filldir, head, table);
	232	if (res)
	233	return res;
	234
	235	file->f_pos = *pos + 1;
	236	}
	237	return 0;
77b14db5 EB	238	}
	239
	240	static int proc_sys_readdir(struct file filp, void dirent, filldir_t filldir)
	241	{
9043476f	242	struct dentry *dentry = filp->f_path.dentry;
77b14db5	243	struct inode *inode = dentry->d_inode;
9043476f AV	244	struct ctl_table_header *head = grab_header(inode);
	245	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
	246	struct ctl_table_header *h = NULL;
77b14db5	247	unsigned long pos;
9043476f AV	248	int ret = -EINVAL;
	249
	250	if (IS_ERR(head))
	251	return PTR_ERR(head);
77b14db5	252
9043476f AV	253	if (table && !table->child) {
9043476f AV	254	WARN_ON(1);
77b14db5	255	goto out;
9043476f AV	256	}
	257
	258	table = table ? table->child : head->ctl_table;
77b14db5 EB	259
	260	ret = 0;
	261	/* Avoid a switch here: arm builds fail with missing __cmpdi2 */
	262	if (filp->f_pos == 0) {
	263	if (filldir(dirent, ".", 1, filp->f_pos,
	264	inode->i_ino, DT_DIR) < 0)
	265	goto out;
	266	filp->f_pos++;
	267	}
	268	if (filp->f_pos == 1) {
	269	if (filldir(dirent, "..", 2, filp->f_pos,
	270	parent_ino(dentry), DT_DIR) < 0)
	271	goto out;
	272	filp->f_pos++;
	273	}
	274	pos = 2;
	275
9043476f AV	276	ret = scan(head, table, &pos, filp, dirent, filldir);
	277	if (ret)
	278	goto out;
77b14db5	279
9043476f AV	280	for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
9043476f AV	281	if (h->attached_to != table)
77b14db5	282	continue;
9043476f AV	283	ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
	284	if (ret) {
	285	sysctl_head_finish(h);
	286	break;
77b14db5 EB	287	}
	288	}
	289	ret = 1;
	290	out:
	291	sysctl_head_finish(head);
	292	return ret;
	293	}
	294
e6305c43	295	static int proc_sys_permission(struct inode *inode, int mask)
77b14db5 EB	296	{
	297	/*
	298	* sysctl entries that are not writeable,
	299	* are _NOT_ writeable, capabilities or not.
	300	*/
f696a365 MS	301	struct ctl_table_header *head;
f696a365 MS	302	struct ctl_table *table;
77b14db5 EB	303	int error;
77b14db5 EB	304
f696a365 MS	305	/* Executable files are not allowed under /proc/sys/ */
	306	if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
	307	return -EACCES;
	308
	309	head = grab_header(inode);
9043476f AV	310	if (IS_ERR(head))
9043476f AV	311	return PTR_ERR(head);
77b14db5	312
f696a365	313	table = PROC_I(inode)->sysctl_entry;
9043476f AV	314	if (!table) /* global root - r-xr-xr-x */
	315	error = mask & MAY_WRITE ? -EACCES : 0;
	316	else /* Use the permissions on the sysctl table entry */
	317	error = sysctl_perm(head->root, table, mask);
77b14db5	318
77b14db5 EB	319	sysctl_head_finish(head);
	320	return error;
	321	}
	322
	323	static int proc_sys_setattr(struct dentry dentry, struct iattr attr)
	324	{
	325	struct inode *inode = dentry->d_inode;
	326	int error;
	327
	328	if (attr->ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID))
	329	return -EPERM;
	330
	331	error = inode_change_ok(inode, attr);
9d0633cf JJ	332	if (!error)
9d0633cf JJ	333	error = inode_setattr(inode, attr);
77b14db5 EB	334
	335	return error;
	336	}
	337
9043476f AV	338	static int proc_sys_getattr(struct vfsmount mnt, struct dentry dentry, struct kstat *stat)
	339	{
	340	struct inode *inode = dentry->d_inode;
	341	struct ctl_table_header *head = grab_header(inode);
	342	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
	343
	344	if (IS_ERR(head))
	345	return PTR_ERR(head);
	346
	347	generic_fillattr(inode, stat);
	348	if (table)
	349	stat->mode = (stat->mode & S_IFMT) \| table->mode;
	350
	351	sysctl_head_finish(head);
	352	return 0;
	353	}
	354
77b14db5 EB	355	static const struct file_operations proc_sys_file_operations = {
	356	.read = proc_sys_read,
	357	.write = proc_sys_write,
9043476f AV	358	};
	359
	360	static const struct file_operations proc_sys_dir_file_operations = {
77b14db5	361	.readdir = proc_sys_readdir,
3222a3e5	362	.llseek = generic_file_llseek,
77b14db5 EB	363	};
77b14db5 EB	364
03a44825	365	static const struct inode_operations proc_sys_inode_operations = {
9043476f AV	366	.permission = proc_sys_permission,
	367	.setattr = proc_sys_setattr,
	368	.getattr = proc_sys_getattr,
	369	};
	370
	371	static const struct inode_operations proc_sys_dir_operations = {
77b14db5 EB	372	.lookup = proc_sys_lookup,
	373	.permission = proc_sys_permission,
	374	.setattr = proc_sys_setattr,
9043476f	375	.getattr = proc_sys_getattr,
77b14db5 EB	376	};
	377
	378	static int proc_sys_revalidate(struct dentry dentry, struct nameidata nd)
	379	{
9043476f AV	380	return !PROC_I(dentry->d_inode)->sysctl->unregistering;
	381	}
	382
	383	static int proc_sys_delete(struct dentry *dentry)
	384	{
	385	return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
	386	}
	387
	388	static int proc_sys_compare(struct dentry dir, struct qstr qstr,
	389	struct qstr *name)
	390	{
	391	struct dentry *dentry = container_of(qstr, struct dentry, d_name);
	392	if (qstr->len != name->len)
	393	return 1;
	394	if (memcmp(qstr->name, name->name, name->len))
	395	return 1;
	396	return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl);
77b14db5 EB	397	}
77b14db5 EB	398
d72f71eb	399	static const struct dentry_operations proc_sys_dentry_operations = {
77b14db5	400	.d_revalidate = proc_sys_revalidate,
9043476f AV	401	.d_delete = proc_sys_delete,
9043476f AV	402	.d_compare = proc_sys_compare,
77b14db5 EB	403	};
77b14db5 EB	404
1e0edd3f	405	int __init proc_sys_init(void)
77b14db5	406	{
e1675231 AD	407	struct proc_dir_entry *proc_sys_root;
e1675231 AD	408
77b14db5	409	proc_sys_root = proc_mkdir("sys", NULL);
9043476f AV	410	proc_sys_root->proc_iops = &proc_sys_dir_operations;
9043476f AV	411	proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
77b14db5 EB	412	proc_sys_root->nlink = 0;
	413	return 0;
	414	}