[linux.git] / fs / generic_acl.c

/*
 * (C) 2005 Andreas Gruenbacher <[email protected]>
 *
 * This file is released under the GPL.
 *
 * Generic ACL support for in-memory filesystems.
 */

#include <linux/sched.h>
#include <linux/gfp.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;
}

const 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,
};

const 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 <[email protected]>
	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>
5a0e3ad6	10	#include <linux/gfp.h>
f0c8bd16 AG	11	#include <linux/fs.h>
f0c8bd16 AG	12	#include <linux/generic_acl.h>
1c7c474c CH	13	#include <linux/posix_acl.h>
1c7c474c CH	14	#include <linux/posix_acl_xattr.h>
f0c8bd16	15
1c7c474c CH	16
	17	static size_t
	18	generic_acl_list(struct dentry dentry, char list, size_t list_size,
	19	const char *name, size_t name_len, int type)
f0c8bd16 AG	20	{
f0c8bd16 AG	21	struct posix_acl *acl;
1c7c474c	22	const char *xname;
f0c8bd16 AG	23	size_t size;
f0c8bd16 AG	24
1c7c474c	25	acl = get_cached_acl(dentry->d_inode, type);
f0c8bd16 AG	26	if (!acl)
	27	return 0;
	28	posix_acl_release(acl);
	29
1c7c474c CH	30	switch (type) {
	31	case ACL_TYPE_ACCESS:
	32	xname = POSIX_ACL_XATTR_ACCESS;
	33	break;
	34	case ACL_TYPE_DEFAULT:
	35	xname = POSIX_ACL_XATTR_DEFAULT;
	36	break;
	37	default:
	38	return 0;
f0c8bd16	39	}
1c7c474c	40	size = strlen(xname) + 1;
f0c8bd16	41	if (list && size <= list_size)
1c7c474c	42	memcpy(list, xname, size);
f0c8bd16 AG	43	return size;
	44	}
	45
1c7c474c CH	46	static int
	47	generic_acl_get(struct dentry dentry, const char name, void *buffer,
	48	size_t size, int type)
f0c8bd16 AG	49	{
	50	struct posix_acl *acl;
	51	int error;
	52
1c7c474c CH	53	if (strcmp(name, "") != 0)
	54	return -EINVAL;
	55
	56	acl = get_cached_acl(dentry->d_inode, type);
f0c8bd16 AG	57	if (!acl)
	58	return -ENODATA;
	59	error = posix_acl_to_xattr(acl, buffer, size);
	60	posix_acl_release(acl);
	61
	62	return error;
	63	}
	64
1c7c474c CH	65	static int
	66	generic_acl_set(struct dentry dentry, const char name, const void *value,
	67	size_t size, int flags, int type)
f0c8bd16	68	{
1c7c474c	69	struct inode *inode = dentry->d_inode;
f0c8bd16 AG	70	struct posix_acl *acl = NULL;
	71	int error;
	72
1c7c474c CH	73	if (strcmp(name, "") != 0)
1c7c474c CH	74	return -EINVAL;
f0c8bd16 AG	75	if (S_ISLNK(inode->i_mode))
f0c8bd16 AG	76	return -EOPNOTSUPP;
3bd858ab	77	if (!is_owner_or_cap(inode))
f0c8bd16 AG	78	return -EPERM;
	79	if (value) {
	80	acl = posix_acl_from_xattr(value, size);
	81	if (IS_ERR(acl))
	82	return PTR_ERR(acl);
	83	}
	84	if (acl) {
	85	mode_t mode;
	86
	87	error = posix_acl_valid(acl);
	88	if (error)
	89	goto failed;
1c7c474c CH	90	switch (type) {
	91	case ACL_TYPE_ACCESS:
	92	mode = inode->i_mode;
	93	error = posix_acl_equiv_mode(acl, &mode);
	94	if (error < 0)
	95	goto failed;
	96	inode->i_mode = mode;
	97	if (error == 0) {
	98	posix_acl_release(acl);
	99	acl = NULL;
	100	}
	101	break;
	102	case ACL_TYPE_DEFAULT:
	103	if (!S_ISDIR(inode->i_mode)) {
	104	error = -EINVAL;
	105	goto failed;
	106	}
	107	break;
f0c8bd16 AG	108	}
f0c8bd16 AG	109	}
1c7c474c	110	set_cached_acl(inode, type, acl);
f0c8bd16 AG	111	error = 0;
	112	failed:
	113	posix_acl_release(acl);
	114	return error;
	115	}
	116
	117	/**
	118	* generic_acl_init - Take care of acl inheritance at @inode create time
f0c8bd16 AG	119	*
	120	* Files created inside a directory with a default ACL inherit the
	121	* directory's default ACL.
	122	*/
	123	int
1c7c474c	124	generic_acl_init(struct inode inode, struct inode dir)
f0c8bd16 AG	125	{
	126	struct posix_acl *acl = NULL;
	127	mode_t mode = inode->i_mode;
	128	int error;
	129
ce3b0f8d	130	inode->i_mode = mode & ~current_umask();
f0c8bd16	131	if (!S_ISLNK(inode->i_mode))
1c7c474c	132	acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
f0c8bd16 AG	133	if (acl) {
	134	struct posix_acl *clone;
	135
	136	if (S_ISDIR(inode->i_mode)) {
	137	clone = posix_acl_clone(acl, GFP_KERNEL);
	138	error = -ENOMEM;
	139	if (!clone)
	140	goto cleanup;
1c7c474c	141	set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
f0c8bd16 AG	142	posix_acl_release(clone);
	143	}
	144	clone = posix_acl_clone(acl, GFP_KERNEL);
	145	error = -ENOMEM;
	146	if (!clone)
	147	goto cleanup;
	148	error = posix_acl_create_masq(clone, &mode);
	149	if (error >= 0) {
	150	inode->i_mode = mode;
	151	if (error > 0)
1c7c474c	152	set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
f0c8bd16 AG	153	}
	154	posix_acl_release(clone);
	155	}
	156	error = 0;
	157
	158	cleanup:
	159	posix_acl_release(acl);
	160	return error;
	161	}
	162
	163	/**
	164	* generic_acl_chmod - change the access acl of @inode upon chmod()
f0c8bd16 AG	165	*
	166	* A chmod also changes the permissions of the owner, group/mask, and
	167	* other ACL entries.
	168	*/
	169	int
1c7c474c	170	generic_acl_chmod(struct inode *inode)
f0c8bd16 AG	171	{
	172	struct posix_acl acl, clone;
	173	int error = 0;
	174
	175	if (S_ISLNK(inode->i_mode))
	176	return -EOPNOTSUPP;
1c7c474c	177	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
f0c8bd16 AG	178	if (acl) {
	179	clone = posix_acl_clone(acl, GFP_KERNEL);
	180	posix_acl_release(acl);
	181	if (!clone)
	182	return -ENOMEM;
	183	error = posix_acl_chmod_masq(clone, inode->i_mode);
	184	if (!error)
1c7c474c	185	set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
f0c8bd16 AG	186	posix_acl_release(clone);
	187	}
	188	return error;
	189	}
1c7c474c CH	190
	191	int
	192	generic_check_acl(struct inode *inode, int mask)
	193	{
	194	struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
	195
	196	if (acl) {
	197	int error = posix_acl_permission(inode, acl, mask);
	198	posix_acl_release(acl);
	199	return error;
	200	}
	201	return -EAGAIN;
	202	}
	203
bb435453	204	const struct xattr_handler generic_acl_access_handler = {
1c7c474c CH	205	.prefix = POSIX_ACL_XATTR_ACCESS,
	206	.flags = ACL_TYPE_ACCESS,
	207	.list = generic_acl_list,
	208	.get = generic_acl_get,
	209	.set = generic_acl_set,
	210	};
	211
bb435453	212	const struct xattr_handler generic_acl_default_handler = {
1c7c474c CH	213	.prefix = POSIX_ACL_XATTR_DEFAULT,
	214	.flags = ACL_TYPE_DEFAULT,
	215	.list = generic_acl_list,
	216	.get = generic_acl_get,
	217	.set = generic_acl_set,
	218	};