[GitHub/mt8127/android_kernel_alcatel_ttab.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 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;
	inode->i_uid = inode->i_gid = 0;
	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, filp, 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 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
	10	static struct dentry_operations proc_sys_dentry_operations;
	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	33	inode->i_mode = table->mode;
5c06fe77	34	inode->i_uid = inode->i_gid = 0;
9043476f AV	35	if (!table->child) {
	36	inode->i_mode \|= S_IFREG;
	37	inode->i_op = &proc_sys_inode_operations;
	38	inode->i_fop = &proc_sys_file_operations;
	39	} else {
	40	inode->i_mode \|= S_IFDIR;
	41	inode->i_nlink = 0;
	42	inode->i_op = &proc_sys_dir_operations;
	43	inode->i_fop = &proc_sys_dir_file_operations;
	44	}
77b14db5 EB	45	out:
	46	return inode;
	47	}
	48
9043476f	49	static struct ctl_table find_in_table(struct ctl_table p, struct qstr *name)
77b14db5 EB	50	{
77b14db5 EB	51	int len;
9043476f	52	for ( ; p->ctl_name \|\| p->procname; p++) {
77b14db5	53
9043476f	54	if (!p->procname)
77b14db5 EB	55	continue;
77b14db5 EB	56
9043476f	57	len = strlen(p->procname);
77b14db5 EB	58	if (len != name->len)
	59	continue;
	60
9043476f	61	if (memcmp(p->procname, name->name, len) != 0)
77b14db5 EB	62	continue;
	63
	64	/* I have a match */
9043476f	65	return p;
77b14db5 EB	66	}
	67	return NULL;
	68	}
	69
81324364	70	static struct ctl_table_header grab_header(struct inode inode)
77b14db5	71	{
9043476f AV	72	if (PROC_I(inode)->sysctl)
	73	return sysctl_head_grab(PROC_I(inode)->sysctl);
	74	else
	75	return sysctl_head_next(NULL);
	76	}
77b14db5	77
9043476f AV	78	static struct dentry proc_sys_lookup(struct inode dir, struct dentry *dentry,
	79	struct nameidata *nd)
	80	{
	81	struct ctl_table_header *head = grab_header(dir);
	82	struct ctl_table *table = PROC_I(dir)->sysctl_entry;
	83	struct ctl_table_header *h = NULL;
	84	struct qstr *name = &dentry->d_name;
	85	struct ctl_table *p;
	86	struct inode *inode;
	87	struct dentry *err = ERR_PTR(-ENOENT);
77b14db5	88
9043476f AV	89	if (IS_ERR(head))
9043476f AV	90	return ERR_CAST(head);
77b14db5	91
9043476f AV	92	if (table && !table->child) {
	93	WARN_ON(1);
	94	goto out;
77b14db5	95	}
77b14db5	96
9043476f	97	table = table ? table->child : head->ctl_table;
77b14db5	98
9043476f AV	99	p = find_in_table(table, name);
	100	if (!p) {
	101	for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
	102	if (h->attached_to != table)
	103	continue;
	104	p = find_in_table(h->attached_by, name);
	105	if (p)
	106	break;
	107	}
77b14db5	108	}
77b14db5	109
9043476f	110	if (!p)
77b14db5 EB	111	goto out;
	112
	113	err = ERR_PTR(-ENOMEM);
9043476f AV	114	inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
	115	if (h)
	116	sysctl_head_finish(h);
	117
77b14db5 EB	118	if (!inode)
	119	goto out;
	120
	121	err = NULL;
	122	dentry->d_op = &proc_sys_dentry_operations;
	123	d_add(dentry, inode);
	124
	125	out:
	126	sysctl_head_finish(head);
	127	return err;
	128	}
	129
7708bfb1 PE	130	static ssize_t proc_sys_call_handler(struct file filp, void __user buf,
7708bfb1 PE	131	size_t count, loff_t *ppos, int write)
77b14db5	132	{
9043476f AV	133	struct inode *inode = filp->f_path.dentry->d_inode;
	134	struct ctl_table_header *head = grab_header(inode);
	135	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
2a2da53b DH	136	ssize_t error;
2a2da53b DH	137	size_t res;
77b14db5	138
9043476f AV	139	if (IS_ERR(head))
9043476f AV	140	return PTR_ERR(head);
77b14db5 EB	141
	142	/*
	143	* At this point we know that the sysctl was not unregistered
	144	* and won't be until we finish.
	145	*/
	146	error = -EPERM;
d7321cd6	147	if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
77b14db5 EB	148	goto out;
77b14db5 EB	149
9043476f AV	150	/* if that can happen at all, it should be -EINVAL, not -EISDIR */
	151	error = -EINVAL;
	152	if (!table->proc_handler)
	153	goto out;
	154
77b14db5 EB	155	/* careful: calling conventions are nasty here */
77b14db5 EB	156	res = count;
7708bfb1	157	error = table->proc_handler(table, write, filp, buf, &res, ppos);
77b14db5 EB	158	if (!error)
	159	error = res;
	160	out:
	161	sysctl_head_finish(head);
	162
	163	return error;
	164	}
	165
7708bfb1	166	static ssize_t proc_sys_read(struct file filp, char __user buf,
77b14db5 EB	167	size_t count, loff_t *ppos)
77b14db5 EB	168	{
7708bfb1 PE	169	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
7708bfb1 PE	170	}
77b14db5	171
7708bfb1 PE	172	static ssize_t proc_sys_write(struct file filp, const char __user buf,
	173	size_t count, loff_t *ppos)
	174	{
	175	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
77b14db5 EB	176	}
	177
	178
	179	static int proc_sys_fill_cache(struct file filp, void dirent,
9043476f AV	180	filldir_t filldir,
	181	struct ctl_table_header *head,
	182	struct ctl_table *table)
77b14db5	183	{
77b14db5 EB	184	struct dentry child, dir = filp->f_path.dentry;
	185	struct inode *inode;
	186	struct qstr qname;
	187	ino_t ino = 0;
	188	unsigned type = DT_UNKNOWN;
77b14db5 EB	189
	190	qname.name = table->procname;
	191	qname.len = strlen(table->procname);
	192	qname.hash = full_name_hash(qname.name, qname.len);
	193
77b14db5 EB	194	child = d_lookup(dir, &qname);
77b14db5 EB	195	if (!child) {
9043476f AV	196	child = d_alloc(dir, &qname);
	197	if (child) {
	198	inode = proc_sys_make_inode(dir->d_sb, head, table);
	199	if (!inode) {
	200	dput(child);
	201	return -ENOMEM;
	202	} else {
	203	child->d_op = &proc_sys_dentry_operations;
	204	d_add(child, inode);
77b14db5	205	}
9043476f AV	206	} else {
9043476f AV	207	return -ENOMEM;
77b14db5 EB	208	}
77b14db5 EB	209	}
77b14db5	210	inode = child->d_inode;
9043476f AV	211	ino = inode->i_ino;
9043476f AV	212	type = inode->i_mode >> 12;
77b14db5	213	dput(child);
9043476f AV	214	return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
	215	}
	216
	217	static int scan(struct ctl_table_header head, ctl_table table,
	218	unsigned long pos, struct file file,
	219	void *dirent, filldir_t filldir)
	220	{
	221
	222	for (; table->ctl_name \|\| table->procname; table++, (*pos)++) {
	223	int res;
	224
	225	/* Can't do anything without a proc name */
	226	if (!table->procname)
	227	continue;
	228
	229	if (*pos < file->f_pos)
	230	continue;
	231
	232	res = proc_sys_fill_cache(file, dirent, filldir, head, table);
	233	if (res)
	234	return res;
	235
	236	file->f_pos = *pos + 1;
	237	}
	238	return 0;
77b14db5 EB	239	}
	240
	241	static int proc_sys_readdir(struct file filp, void dirent, filldir_t filldir)
	242	{
9043476f	243	struct dentry *dentry = filp->f_path.dentry;
77b14db5	244	struct inode *inode = dentry->d_inode;
9043476f AV	245	struct ctl_table_header *head = grab_header(inode);
	246	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
	247	struct ctl_table_header *h = NULL;
77b14db5	248	unsigned long pos;
9043476f AV	249	int ret = -EINVAL;
	250
	251	if (IS_ERR(head))
	252	return PTR_ERR(head);
77b14db5	253
9043476f AV	254	if (table && !table->child) {
9043476f AV	255	WARN_ON(1);
77b14db5	256	goto out;
9043476f AV	257	}
	258
	259	table = table ? table->child : head->ctl_table;
77b14db5 EB	260
	261	ret = 0;
	262	/* Avoid a switch here: arm builds fail with missing __cmpdi2 */
	263	if (filp->f_pos == 0) {
	264	if (filldir(dirent, ".", 1, filp->f_pos,
	265	inode->i_ino, DT_DIR) < 0)
	266	goto out;
	267	filp->f_pos++;
	268	}
	269	if (filp->f_pos == 1) {
	270	if (filldir(dirent, "..", 2, filp->f_pos,
	271	parent_ino(dentry), DT_DIR) < 0)
	272	goto out;
	273	filp->f_pos++;
	274	}
	275	pos = 2;
	276
9043476f AV	277	ret = scan(head, table, &pos, filp, dirent, filldir);
	278	if (ret)
	279	goto out;
77b14db5	280
9043476f AV	281	for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
9043476f AV	282	if (h->attached_to != table)
77b14db5	283	continue;
9043476f AV	284	ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
	285	if (ret) {
	286	sysctl_head_finish(h);
	287	break;
77b14db5 EB	288	}
	289	}
	290	ret = 1;
	291	out:
	292	sysctl_head_finish(head);
	293	return ret;
	294	}
	295
e6305c43	296	static int proc_sys_permission(struct inode *inode, int mask)
77b14db5 EB	297	{
	298	/*
	299	* sysctl entries that are not writeable,
	300	* are _NOT_ writeable, capabilities or not.
	301	*/
f696a365 MS	302	struct ctl_table_header *head;
f696a365 MS	303	struct ctl_table *table;
77b14db5 EB	304	int error;
77b14db5 EB	305
f696a365 MS	306	/* Executable files are not allowed under /proc/sys/ */
	307	if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
	308	return -EACCES;
	309
	310	head = grab_header(inode);
9043476f AV	311	if (IS_ERR(head))
9043476f AV	312	return PTR_ERR(head);
77b14db5	313
f696a365	314	table = PROC_I(inode)->sysctl_entry;
9043476f AV	315	if (!table) /* global root - r-xr-xr-x */
	316	error = mask & MAY_WRITE ? -EACCES : 0;
	317	else /* Use the permissions on the sysctl table entry */
	318	error = sysctl_perm(head->root, table, mask);
77b14db5	319
77b14db5 EB	320	sysctl_head_finish(head);
	321	return error;
	322	}
	323
	324	static int proc_sys_setattr(struct dentry dentry, struct iattr attr)
	325	{
	326	struct inode *inode = dentry->d_inode;
	327	int error;
	328
	329	if (attr->ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID))
	330	return -EPERM;
	331
	332	error = inode_change_ok(inode, attr);
9d0633cf JJ	333	if (!error)
9d0633cf JJ	334	error = inode_setattr(inode, attr);
77b14db5 EB	335
	336	return error;
	337	}
	338
9043476f AV	339	static int proc_sys_getattr(struct vfsmount mnt, struct dentry dentry, struct kstat *stat)
	340	{
	341	struct inode *inode = dentry->d_inode;
	342	struct ctl_table_header *head = grab_header(inode);
	343	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
	344
	345	if (IS_ERR(head))
	346	return PTR_ERR(head);
	347
	348	generic_fillattr(inode, stat);
	349	if (table)
	350	stat->mode = (stat->mode & S_IFMT) \| table->mode;
	351
	352	sysctl_head_finish(head);
	353	return 0;
	354	}
	355
77b14db5 EB	356	static const struct file_operations proc_sys_file_operations = {
	357	.read = proc_sys_read,
	358	.write = proc_sys_write,
9043476f AV	359	};
	360
	361	static const struct file_operations proc_sys_dir_file_operations = {
77b14db5	362	.readdir = proc_sys_readdir,
3222a3e5	363	.llseek = generic_file_llseek,
77b14db5 EB	364	};
77b14db5 EB	365
03a44825	366	static const struct inode_operations proc_sys_inode_operations = {
9043476f AV	367	.permission = proc_sys_permission,
	368	.setattr = proc_sys_setattr,
	369	.getattr = proc_sys_getattr,
	370	};
	371
	372	static const struct inode_operations proc_sys_dir_operations = {
77b14db5 EB	373	.lookup = proc_sys_lookup,
	374	.permission = proc_sys_permission,
	375	.setattr = proc_sys_setattr,
9043476f	376	.getattr = proc_sys_getattr,
77b14db5 EB	377	};
	378
	379	static int proc_sys_revalidate(struct dentry dentry, struct nameidata nd)
	380	{
9043476f AV	381	return !PROC_I(dentry->d_inode)->sysctl->unregistering;
	382	}
	383
	384	static int proc_sys_delete(struct dentry *dentry)
	385	{
	386	return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
	387	}
	388
	389	static int proc_sys_compare(struct dentry dir, struct qstr qstr,
	390	struct qstr *name)
	391	{
	392	struct dentry *dentry = container_of(qstr, struct dentry, d_name);
	393	if (qstr->len != name->len)
	394	return 1;
	395	if (memcmp(qstr->name, name->name, name->len))
	396	return 1;
	397	return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl);
77b14db5 EB	398	}
	399
	400	static struct dentry_operations proc_sys_dentry_operations = {
	401	.d_revalidate = proc_sys_revalidate,
9043476f AV	402	.d_delete = proc_sys_delete,
9043476f AV	403	.d_compare = proc_sys_compare,
77b14db5 EB	404	};
77b14db5 EB	405
1e0edd3f	406	int __init proc_sys_init(void)
77b14db5	407	{
e1675231 AD	408	struct proc_dir_entry *proc_sys_root;
e1675231 AD	409
77b14db5	410	proc_sys_root = proc_mkdir("sys", NULL);
9043476f AV	411	proc_sys_root->proc_iops = &proc_sys_dir_operations;
9043476f AV	412	proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
77b14db5 EB	413	proc_sys_root->nlink = 0;
	414	return 0;
	415	}