[net-next-2.6.git] / fs / generic_acl.c

/*
 * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
 *
 * This file is released under the GPL.
 *
 * Generic ACL support for in-memory filesystems.
 */

#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/generic_acl.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>


static size_t
generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
		const char *name, size_t name_len, int type)
{
	struct posix_acl *acl;
	const char *xname;
	size_t size;

	acl = get_cached_acl(dentry->d_inode, type);
	if (!acl)
		return 0;
	posix_acl_release(acl);

	switch (type) {
	case ACL_TYPE_ACCESS:
		xname = POSIX_ACL_XATTR_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		xname = POSIX_ACL_XATTR_DEFAULT;
		break;
	default:
		return 0;
	}
	size = strlen(xname) + 1;
	if (list && size <= list_size)
		memcpy(list, xname, size);
	return size;
}

static int
generic_acl_get(struct dentry *dentry, const char *name, void *buffer,
		     size_t size, int type)
{
	struct posix_acl *acl;
	int error;

	if (strcmp(name, "") != 0)
		return -EINVAL;

	acl = get_cached_acl(dentry->d_inode, type);
	if (!acl)
		return -ENODATA;
	error = posix_acl_to_xattr(acl, buffer, size);
	posix_acl_release(acl);

	return error;
}

static int
generic_acl_set(struct dentry *dentry, const char *name, const void *value,
		     size_t size, int flags, int type)
{
	struct inode *inode = dentry->d_inode;
	struct posix_acl *acl = NULL;
	int error;

	if (strcmp(name, "") != 0)
		return -EINVAL;
	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!is_owner_or_cap(inode))
		return -EPERM;
	if (value) {
		acl = posix_acl_from_xattr(value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
	}
	if (acl) {
		mode_t mode;

		error = posix_acl_valid(acl);
		if (error)
			goto failed;
		switch (type) {
		case ACL_TYPE_ACCESS:
			mode = inode->i_mode;
			error = posix_acl_equiv_mode(acl, &mode);
			if (error < 0)
				goto failed;
			inode->i_mode = mode;
			if (error == 0) {
				posix_acl_release(acl);
				acl = NULL;
			}
			break;
		case ACL_TYPE_DEFAULT:
			if (!S_ISDIR(inode->i_mode)) {
				error = -EINVAL;
				goto failed;
			}
			break;
		}
	}
	set_cached_acl(inode, type, acl);
	error = 0;
failed:
	posix_acl_release(acl);
	return error;
}

/**
 * generic_acl_init  -  Take care of acl inheritance at @inode create time
 *
 * Files created inside a directory with a default ACL inherit the
 * directory's default ACL.
 */
int
generic_acl_init(struct inode *inode, struct inode *dir)
{
	struct posix_acl *acl = NULL;
	mode_t mode = inode->i_mode;
	int error;

	inode->i_mode = mode & ~current_umask();
	if (!S_ISLNK(inode->i_mode))
		acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
	if (acl) {
		struct posix_acl *clone;

		if (S_ISDIR(inode->i_mode)) {
			clone = posix_acl_clone(acl, GFP_KERNEL);
			error = -ENOMEM;
			if (!clone)
				goto cleanup;
			set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
			posix_acl_release(clone);
		}
		clone = posix_acl_clone(acl, GFP_KERNEL);
		error = -ENOMEM;
		if (!clone)
			goto cleanup;
		error = posix_acl_create_masq(clone, &mode);
		if (error >= 0) {
			inode->i_mode = mode;
			if (error > 0)
				set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
		}
		posix_acl_release(clone);
	}
	error = 0;

cleanup:
	posix_acl_release(acl);
	return error;
}

/**
 * generic_acl_chmod  -  change the access acl of @inode upon chmod()
 *
 * A chmod also changes the permissions of the owner, group/mask, and
 * other ACL entries.
 */
int
generic_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
	int error = 0;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
	if (acl) {
		clone = posix_acl_clone(acl, GFP_KERNEL);
		posix_acl_release(acl);
		if (!clone)
			return -ENOMEM;
		error = posix_acl_chmod_masq(clone, inode->i_mode);
		if (!error)
			set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
		posix_acl_release(clone);
	}
	return error;
}

int
generic_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS);

	if (acl) {
		int error = posix_acl_permission(inode, acl, mask);
		posix_acl_release(acl);
		return error;
	}
	return -EAGAIN;
}

struct xattr_handler generic_acl_access_handler = {
	.prefix = POSIX_ACL_XATTR_ACCESS,
	.flags	= ACL_TYPE_ACCESS,
	.list	= generic_acl_list,
	.get	= generic_acl_get,
	.set	= generic_acl_set,
};

struct xattr_handler generic_acl_default_handler = {
	.prefix = POSIX_ACL_XATTR_DEFAULT,
	.flags	= ACL_TYPE_DEFAULT,
	.list	= generic_acl_list,
	.get	= generic_acl_get,
	.set	= generic_acl_set,
};
Commit	Line	Data
f0c8bd16	1	/*
f0c8bd16 AG	2	* (C) 2005 Andreas Gruenbacher <agruen@suse.de>
	3	*
	4	* This file is released under the GPL.
1c7c474c CH	5	*
1c7c474c CH	6	* Generic ACL support for in-memory filesystems.
f0c8bd16 AG	7	*/
	8
	9	#include <linux/sched.h>
	10	#include <linux/fs.h>
	11	#include <linux/generic_acl.h>
1c7c474c CH	12	#include <linux/posix_acl.h>
1c7c474c CH	13	#include <linux/posix_acl_xattr.h>
f0c8bd16	14
1c7c474c CH	15
	16	static size_t
	17	generic_acl_list(struct dentry dentry, char list, size_t list_size,
	18	const char *name, size_t name_len, int type)
f0c8bd16 AG	19	{
f0c8bd16 AG	20	struct posix_acl *acl;
1c7c474c	21	const char *xname;
f0c8bd16 AG	22	size_t size;
f0c8bd16 AG	23
1c7c474c	24	acl = get_cached_acl(dentry->d_inode, type);
f0c8bd16 AG	25	if (!acl)
	26	return 0;
	27	posix_acl_release(acl);
	28
1c7c474c CH	29	switch (type) {
	30	case ACL_TYPE_ACCESS:
	31	xname = POSIX_ACL_XATTR_ACCESS;
	32	break;
	33	case ACL_TYPE_DEFAULT:
	34	xname = POSIX_ACL_XATTR_DEFAULT;
	35	break;
	36	default:
	37	return 0;
f0c8bd16	38	}
1c7c474c	39	size = strlen(xname) + 1;
f0c8bd16	40	if (list && size <= list_size)
1c7c474c	41	memcpy(list, xname, size);
f0c8bd16 AG	42	return size;
	43	}
	44
1c7c474c CH	45	static int
	46	generic_acl_get(struct dentry dentry, const char name, void *buffer,
	47	size_t size, int type)
f0c8bd16 AG	48	{
	49	struct posix_acl *acl;
	50	int error;
	51
1c7c474c CH	52	if (strcmp(name, "") != 0)
	53	return -EINVAL;
	54
	55	acl = get_cached_acl(dentry->d_inode, type);
f0c8bd16 AG	56	if (!acl)
	57	return -ENODATA;
	58	error = posix_acl_to_xattr(acl, buffer, size);
	59	posix_acl_release(acl);
	60
	61	return error;
	62	}
	63
1c7c474c CH	64	static int
	65	generic_acl_set(struct dentry dentry, const char name, const void *value,
	66	size_t size, int flags, int type)
f0c8bd16	67	{
1c7c474c	68	struct inode *inode = dentry->d_inode;
f0c8bd16 AG	69	struct posix_acl *acl = NULL;
	70	int error;
	71
1c7c474c CH	72	if (strcmp(name, "") != 0)
1c7c474c CH	73	return -EINVAL;
f0c8bd16 AG	74	if (S_ISLNK(inode->i_mode))
f0c8bd16 AG	75	return -EOPNOTSUPP;
3bd858ab	76	if (!is_owner_or_cap(inode))
f0c8bd16 AG	77	return -EPERM;
	78	if (value) {
	79	acl = posix_acl_from_xattr(value, size);
	80	if (IS_ERR(acl))
	81	return PTR_ERR(acl);
	82	}
	83	if (acl) {
	84	mode_t mode;
	85
	86	error = posix_acl_valid(acl);
	87	if (error)
	88	goto failed;
1c7c474c CH	89	switch (type) {
	90	case ACL_TYPE_ACCESS:
	91	mode = inode->i_mode;
	92	error = posix_acl_equiv_mode(acl, &mode);
	93	if (error < 0)
	94	goto failed;
	95	inode->i_mode = mode;
	96	if (error == 0) {
	97	posix_acl_release(acl);
	98	acl = NULL;
	99	}
	100	break;
	101	case ACL_TYPE_DEFAULT:
	102	if (!S_ISDIR(inode->i_mode)) {
	103	error = -EINVAL;
	104	goto failed;
	105	}
	106	break;
f0c8bd16 AG	107	}
f0c8bd16 AG	108	}
1c7c474c	109	set_cached_acl(inode, type, acl);
f0c8bd16 AG	110	error = 0;
	111	failed:
	112	posix_acl_release(acl);
	113	return error;
	114	}
	115
	116	/**
	117	* generic_acl_init - Take care of acl inheritance at @inode create time
f0c8bd16 AG	118	*
	119	* Files created inside a directory with a default ACL inherit the
	120	* directory's default ACL.
	121	*/
	122	int
1c7c474c	123	generic_acl_init(struct inode inode, struct inode dir)
f0c8bd16 AG	124	{
	125	struct posix_acl *acl = NULL;
	126	mode_t mode = inode->i_mode;
	127	int error;
	128
ce3b0f8d	129	inode->i_mode = mode & ~current_umask();
f0c8bd16	130	if (!S_ISLNK(inode->i_mode))
1c7c474c	131	acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
f0c8bd16 AG	132	if (acl) {
	133	struct posix_acl *clone;
	134
	135	if (S_ISDIR(inode->i_mode)) {
	136	clone = posix_acl_clone(acl, GFP_KERNEL);
	137	error = -ENOMEM;
	138	if (!clone)
	139	goto cleanup;
1c7c474c	140	set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
f0c8bd16 AG	141	posix_acl_release(clone);
	142	}
	143	clone = posix_acl_clone(acl, GFP_KERNEL);
	144	error = -ENOMEM;
	145	if (!clone)
	146	goto cleanup;
	147	error = posix_acl_create_masq(clone, &mode);
	148	if (error >= 0) {
	149	inode->i_mode = mode;
	150	if (error > 0)
1c7c474c	151	set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
f0c8bd16 AG	152	}
	153	posix_acl_release(clone);
	154	}
	155	error = 0;
	156
	157	cleanup:
	158	posix_acl_release(acl);
	159	return error;
	160	}
	161
	162	/**
	163	* generic_acl_chmod - change the access acl of @inode upon chmod()
f0c8bd16 AG	164	*
	165	* A chmod also changes the permissions of the owner, group/mask, and
	166	* other ACL entries.
	167	*/
	168	int
1c7c474c	169	generic_acl_chmod(struct inode *inode)
f0c8bd16 AG	170	{
	171	struct posix_acl acl, clone;
	172	int error = 0;
	173
	174	if (S_ISLNK(inode->i_mode))
	175	return -EOPNOTSUPP;
1c7c474c	176	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
f0c8bd16 AG	177	if (acl) {
	178	clone = posix_acl_clone(acl, GFP_KERNEL);
	179	posix_acl_release(acl);
	180	if (!clone)
	181	return -ENOMEM;
	182	error = posix_acl_chmod_masq(clone, inode->i_mode);
	183	if (!error)
1c7c474c	184	set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
f0c8bd16 AG	185	posix_acl_release(clone);
	186	}
	187	return error;
	188	}
1c7c474c CH	189
	190	int
	191	generic_check_acl(struct inode *inode, int mask)
	192	{
	193	struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
	194
	195	if (acl) {
	196	int error = posix_acl_permission(inode, acl, mask);
	197	posix_acl_release(acl);
	198	return error;
	199	}
	200	return -EAGAIN;
	201	}
	202
	203	struct xattr_handler generic_acl_access_handler = {
	204	.prefix = POSIX_ACL_XATTR_ACCESS,
	205	.flags = ACL_TYPE_ACCESS,
	206	.list = generic_acl_list,
	207	.get = generic_acl_get,
	208	.set = generic_acl_set,
	209	};
	210
	211	struct xattr_handler generic_acl_default_handler = {
	212	.prefix = POSIX_ACL_XATTR_DEFAULT,
	213	.flags = ACL_TYPE_DEFAULT,
	214	.list = generic_acl_list,
	215	.get = generic_acl_get,
	216	.set = generic_acl_set,
	217	};