[linux-2.6-block.git] / fs / ext3 / acl.c

/*
 * linux/fs/ext3/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include "ext3.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext3_acl_from_disk(const void *value, size_t size)
{
	const char *end = (char *)value + size;
	int n, count;
	struct posix_acl *acl;

	if (!value)
		return NULL;
	if (size < sizeof(ext3_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext3_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT3_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext3_acl_header);
	count = ext3_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	acl = posix_acl_alloc(count, GFP_NOFS);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	for (n=0; n < count; n++) {
		ext3_acl_entry *entry =
			(ext3_acl_entry *)value;
		if ((char *)value + sizeof(ext3_acl_entry_short) > end)
			goto fail;
		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
		switch(acl->a_entries[n].e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				value = (char *)value +
					sizeof(ext3_acl_entry_short);
				break;

			case ACL_USER:
				value = (char *)value + sizeof(ext3_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_uid =
					make_kuid(&init_user_ns,
						  le32_to_cpu(entry->e_id));
				break;
			case ACL_GROUP:
				value = (char *)value + sizeof(ext3_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_gid =
					make_kgid(&init_user_ns,
						  le32_to_cpu(entry->e_id));
				break;

			default:
				goto fail;
		}
	}
	if (value != end)
		goto fail;
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

/*
 * Convert from in-memory to filesystem representation.
 */
static void *
ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext3_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext3_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
			sizeof(ext3_acl_entry), GFP_NOFS);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext3_acl_header);
	for (n=0; n < acl->a_count; n++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
		ext3_acl_entry *entry = (ext3_acl_entry *)e;
		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
		entry->e_perm = cpu_to_le16(acl_e->e_perm);
		switch(acl_e->e_tag) {
			case ACL_USER:
				entry->e_id = cpu_to_le32(
					from_kuid(&init_user_ns, acl_e->e_uid));
				e += sizeof(ext3_acl_entry);
				break;
			case ACL_GROUP:
				entry->e_id = cpu_to_le32(
					from_kgid(&init_user_ns, acl_e->e_gid));
				e += sizeof(ext3_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext3_acl_entry_short);
				break;

			default:
				goto fail;
		}
	}
	return (char *)ext_acl;

fail:
	kfree(ext_acl);
	return ERR_PTR(-EINVAL);
}

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: don't care
 */
struct posix_acl *
ext3_get_acl(struct inode *inode, int type)
{
	int name_index;
	char *value = NULL;
	struct posix_acl *acl;
	int retval;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}

	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_NOFS);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext3_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext3_acl_from_disk(value, retval);
	else if (retval == -ENODATA || retval == -ENOSYS)
		acl = NULL;
	else
		acl = ERR_PTR(retval);
	kfree(value);

	if (!IS_ERR(acl))
		set_cached_acl(inode, type, acl);

	return acl;
}

/*
 * Set the access or default ACL of an inode.
 *
 * inode->i_mutex: down unless called from ext3_new_inode
 */
static int
__ext3_set_acl(handle_t *handle, struct inode *inode, int type,
	     struct posix_acl *acl)
{
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
			if (acl) {
				error = posix_acl_equiv_mode(acl, &inode->i_mode);
				if (error < 0)
					return error;
				else {
					inode->i_ctime = CURRENT_TIME_SEC;
					ext3_mark_inode_dirty(handle, inode);
					if (error == 0)
						acl = NULL;
				}
			}
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
	if (acl) {
		value = ext3_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext3_xattr_set_handle(handle, inode, name_index, "",
				      value, size, 0);

	kfree(value);

	if (!error)
		set_cached_acl(inode, type, acl);

	return error;
}

int
ext3_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	handle_t *handle;
	int error, retries = 0;

retry:
	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
	if (IS_ERR(handle))
		return PTR_ERR(handle);
	error = __ext3_set_acl(handle, inode, type, acl);
	ext3_journal_stop(handle);
	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
	return error;
}

/*
 * Initialize the ACLs of a new inode. Called from ext3_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
{
	struct posix_acl *default_acl, *acl;
	int error;

	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	if (error)
		return error;

	if (default_acl) {
		error = __ext3_set_acl(handle, inode, ACL_TYPE_DEFAULT,
				       default_acl);
		posix_acl_release(default_acl);
	}
	if (acl) {
		if (!error)
			error = __ext3_set_acl(handle, inode, ACL_TYPE_ACCESS,
					       acl);
		posix_acl_release(acl);
	}
	return error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext3/acl.c
	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
	5	*/
	6
4613ad18	7	#include "ext3.h"
1da177e4 LT	8	#include "xattr.h"
	9	#include "acl.h"
	10
	11	/*
	12	* Convert from filesystem to in-memory representation.
	13	*/
	14	static struct posix_acl *
	15	ext3_acl_from_disk(const void *value, size_t size)
	16	{
	17	const char end = (char )value + size;
	18	int n, count;
	19	struct posix_acl *acl;
	20
	21	if (!value)
	22	return NULL;
	23	if (size < sizeof(ext3_acl_header))
	24	return ERR_PTR(-EINVAL);
	25	if (((ext3_acl_header *)value)->a_version !=
	26	cpu_to_le32(EXT3_ACL_VERSION))
	27	return ERR_PTR(-EINVAL);
	28	value = (char *)value + sizeof(ext3_acl_header);
	29	count = ext3_acl_count(size);
	30	if (count < 0)
	31	return ERR_PTR(-EINVAL);
	32	if (count == 0)
	33	return NULL;
c587f0c0	34	acl = posix_acl_alloc(count, GFP_NOFS);
1da177e4 LT	35	if (!acl)
	36	return ERR_PTR(-ENOMEM);
	37	for (n=0; n < count; n++) {
	38	ext3_acl_entry *entry =
	39	(ext3_acl_entry *)value;
	40	if ((char *)value + sizeof(ext3_acl_entry_short) > end)
	41	goto fail;
	42	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	43	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	44	switch(acl->a_entries[n].e_tag) {
	45	case ACL_USER_OBJ:
	46	case ACL_GROUP_OBJ:
	47	case ACL_MASK:
	48	case ACL_OTHER:
	49	value = (char *)value +
	50	sizeof(ext3_acl_entry_short);
1da177e4 LT	51	break;
	52
	53	case ACL_USER:
af84df93 EB	54	value = (char *)value + sizeof(ext3_acl_entry);
	55	if ((char *)value > end)
	56	goto fail;
	57	acl->a_entries[n].e_uid =
	58	make_kuid(&init_user_ns,
	59	le32_to_cpu(entry->e_id));
	60	break;
1da177e4 LT	61	case ACL_GROUP:
	62	value = (char *)value + sizeof(ext3_acl_entry);
	63	if ((char *)value > end)
	64	goto fail;
af84df93 EB	65	acl->a_entries[n].e_gid =
	66	make_kgid(&init_user_ns,
	67	le32_to_cpu(entry->e_id));
1da177e4 LT	68	break;
	69
	70	default:
	71	goto fail;
	72	}
	73	}
	74	if (value != end)
	75	goto fail;
	76	return acl;
	77
	78	fail:
	79	posix_acl_release(acl);
	80	return ERR_PTR(-EINVAL);
	81	}
	82
	83	/*
	84	* Convert from in-memory to filesystem representation.
	85	*/
	86	static void *
	87	ext3_acl_to_disk(const struct posix_acl acl, size_t size)
	88	{
	89	ext3_acl_header *ext_acl;
	90	char *e;
	91	size_t n;
	92
	93	*size = ext3_acl_size(acl->a_count);
f52720ca	94	ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
c587f0c0	95	sizeof(ext3_acl_entry), GFP_NOFS);
1da177e4 LT	96	if (!ext_acl)
	97	return ERR_PTR(-ENOMEM);
	98	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
	99	e = (char *)ext_acl + sizeof(ext3_acl_header);
	100	for (n=0; n < acl->a_count; n++) {
af84df93	101	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
1da177e4	102	ext3_acl_entry entry = (ext3_acl_entry )e;
af84df93 EB	103	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	104	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	105	switch(acl_e->e_tag) {
1da177e4	106	case ACL_USER:
af84df93 EB	107	entry->e_id = cpu_to_le32(
	108	from_kuid(&init_user_ns, acl_e->e_uid));
	109	e += sizeof(ext3_acl_entry);
	110	break;
1da177e4	111	case ACL_GROUP:
af84df93 EB	112	entry->e_id = cpu_to_le32(
af84df93 EB	113	from_kgid(&init_user_ns, acl_e->e_gid));
1da177e4 LT	114	e += sizeof(ext3_acl_entry);
	115	break;
	116
	117	case ACL_USER_OBJ:
	118	case ACL_GROUP_OBJ:
	119	case ACL_MASK:
	120	case ACL_OTHER:
	121	e += sizeof(ext3_acl_entry_short);
	122	break;
	123
	124	default:
	125	goto fail;
	126	}
	127	}
	128	return (char *)ext_acl;
	129
	130	fail:
	131	kfree(ext_acl);
	132	return ERR_PTR(-EINVAL);
	133	}
	134
1da177e4 LT	135	/*
	136	* Inode operation get_posix_acl().
	137	*
1b1dcc1b	138	* inode->i_mutex: don't care
1da177e4	139	*/
4e34e719	140	struct posix_acl *
1da177e4 LT	141	ext3_get_acl(struct inode *inode, int type)
1da177e4 LT	142	{
1da177e4 LT	143	int name_index;
	144	char *value = NULL;
	145	struct posix_acl *acl;
	146	int retval;
	147
073aaa1b AV	148	switch (type) {
	149	case ACL_TYPE_ACCESS:
	150	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	151	break;
	152	case ACL_TYPE_DEFAULT:
	153	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	154	break;
	155	default:
	156	BUG();
1da177e4	157	}
073aaa1b	158
1da177e4 LT	159	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
1da177e4 LT	160	if (retval > 0) {
c587f0c0	161	value = kmalloc(retval, GFP_NOFS);
1da177e4 LT	162	if (!value)
	163	return ERR_PTR(-ENOMEM);
	164	retval = ext3_xattr_get(inode, name_index, "", value, retval);
	165	}
	166	if (retval > 0)
	167	acl = ext3_acl_from_disk(value, retval);
	168	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	169	acl = NULL;
	170	else
	171	acl = ERR_PTR(retval);
	172	kfree(value);
	173
073aaa1b AV	174	if (!IS_ERR(acl))
073aaa1b AV	175	set_cached_acl(inode, type, acl);
1da177e4	176
1da177e4 LT	177	return acl;
	178	}
	179
	180	/*
	181	* Set the access or default ACL of an inode.
	182	*
1b1dcc1b	183	* inode->i_mutex: down unless called from ext3_new_inode
1da177e4 LT	184	*/
1da177e4 LT	185	static int
64e178a7	186	__ext3_set_acl(handle_t handle, struct inode inode, int type,
1da177e4 LT	187	struct posix_acl *acl)
1da177e4 LT	188	{
1da177e4 LT	189	int name_index;
1da177e4 LT	190	void *value = NULL;
dfa08592	191	size_t size = 0;
1da177e4 LT	192	int error;
1da177e4 LT	193
1da177e4 LT	194	switch(type) {
	195	case ACL_TYPE_ACCESS:
	196	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	197	if (acl) {
d6952123	198	error = posix_acl_equiv_mode(acl, &inode->i_mode);
1da177e4 LT	199	if (error < 0)
	200	return error;
	201	else {
30e2bab2	202	inode->i_ctime = CURRENT_TIME_SEC;
1da177e4 LT	203	ext3_mark_inode_dirty(handle, inode);
	204	if (error == 0)
	205	acl = NULL;
	206	}
	207	}
	208	break;
	209
	210	case ACL_TYPE_DEFAULT:
	211	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	212	if (!S_ISDIR(inode->i_mode))
	213	return acl ? -EACCES : 0;
	214	break;
	215
	216	default:
	217	return -EINVAL;
	218	}
e9ad5620	219	if (acl) {
1da177e4 LT	220	value = ext3_acl_to_disk(acl, &size);
	221	if (IS_ERR(value))
	222	return (int)PTR_ERR(value);
	223	}
	224
	225	error = ext3_xattr_set_handle(handle, inode, name_index, "",
	226	value, size, 0);
	227
	228	kfree(value);
1da177e4	229
073aaa1b AV	230	if (!error)
	231	set_cached_acl(inode, type, acl);
	232
1da177e4 LT	233	return error;
	234	}
	235
1da177e4	236	int
64e178a7	237	ext3_set_acl(struct inode inode, struct posix_acl acl, int type)
1da177e4	238	{
bc26ab5f	239	handle_t *handle;
64e178a7	240	int error, retries = 0;
1da177e4	241
bc26ab5f	242	retry:
64e178a7 CH	243	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
	244	if (IS_ERR(handle))
	245	return PTR_ERR(handle);
	246	error = __ext3_set_acl(handle, inode, type, acl);
bc26ab5f	247	ext3_journal_stop(handle);
64e178a7	248	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
bc26ab5f	249	goto retry;
1da177e4 LT	250	return error;
	251	}
	252
	253	/*
64e178a7 CH	254	* Initialize the ACLs of a new inode. Called from ext3_new_inode.
	255	*
	256	* dir->i_mutex: down
	257	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4	258	*/
64e178a7 CH	259	int
64e178a7 CH	260	ext3_init_acl(handle_t handle, struct inode inode, struct inode *dir)
1da177e4	261	{
64e178a7	262	struct posix_acl default_acl, acl;
1da177e4 LT	263	int error;
1da177e4 LT	264
64e178a7 CH	265	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	266	if (error)
	267	return error;
1da177e4	268
64e178a7 CH	269	if (default_acl) {
	270	error = __ext3_set_acl(handle, inode, ACL_TYPE_DEFAULT,
	271	default_acl);
	272	posix_acl_release(default_acl);
	273	}
	274	if (acl) {
	275	if (!error)
	276	error = __ext3_set_acl(handle, inode, ACL_TYPE_ACCESS,
	277	acl);
	278	posix_acl_release(acl);
	279	}
1da177e4 LT	280	return error;
1da177e4 LT	281	}