[linux.git] / fs / xattr_acl.c

/*
 * linux/fs/xattr_acl.c
 *
 * Almost all from linux/fs/ext2/acl.c:
 * Copyright (C) 2001 by Andreas Gruenbacher, <[email protected]>
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>


/*
 * Convert from extended attribute to in-memory representation.
 */
struct posix_acl *
posix_acl_from_xattr(const void *value, size_t size)
{
	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
	int count;
	struct posix_acl *acl;
	struct posix_acl_entry *acl_e;

	if (!value)
		return NULL;
	if (size < sizeof(posix_acl_xattr_header))
		 return ERR_PTR(-EINVAL);
	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
		return ERR_PTR(-EOPNOTSUPP);

	count = posix_acl_xattr_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	
	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	acl_e = acl->a_entries;
	
	for (end = entry + count; entry != end; acl_e++, entry++) {
		acl_e->e_tag  = le16_to_cpu(entry->e_tag);
		acl_e->e_perm = le16_to_cpu(entry->e_perm);

		switch(acl_e->e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				acl_e->e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				acl_e->e_id = le32_to_cpu(entry->e_id);
				break;

			default:
				goto fail;
		}
	}
	return acl;

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

/*
 * Convert from in-memory to extended attribute representation.
 */
int
posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size)
{
	posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
	posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
	int real_size, n;

	real_size = posix_acl_xattr_size(acl->a_count);
	if (!buffer)
		return real_size;
	if (real_size > size)
		return -ERANGE;
	
	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);

	for (n=0; n < acl->a_count; n++, ext_entry++) {
		ext_entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
		ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
		ext_entry->e_id   = cpu_to_le32(acl->a_entries[n].e_id);
	}
	return real_size;
}
EXPORT_SYMBOL (posix_acl_to_xattr);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/xattr_acl.c
	3	*
	4	* Almost all from linux/fs/ext2/acl.c:
	5	* Copyright (C) 2001 by Andreas Gruenbacher, <[email protected]>
	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/sched.h>
	10	#include <linux/slab.h>
	11	#include <linux/fs.h>
	12	#include <linux/posix_acl_xattr.h>
	13
	14
	15	/*
	16	* Convert from extended attribute to in-memory representation.
	17	*/
	18	struct posix_acl *
	19	posix_acl_from_xattr(const void *value, size_t size)
	20	{
	21	posix_acl_xattr_header header = (posix_acl_xattr_header )value;
	22	posix_acl_xattr_entry entry = (posix_acl_xattr_entry )(header+1), *end;
	23	int count;
	24	struct posix_acl *acl;
	25	struct posix_acl_entry *acl_e;
	26
	27	if (!value)
	28	return NULL;
	29	if (size < sizeof(posix_acl_xattr_header))
	30	return ERR_PTR(-EINVAL);
	31	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
	32	return ERR_PTR(-EOPNOTSUPP);
	33
	34	count = posix_acl_xattr_count(size);
	35	if (count < 0)
	36	return ERR_PTR(-EINVAL);
	37	if (count == 0)
	38	return NULL;
	39
	40	acl = posix_acl_alloc(count, GFP_KERNEL);
	41	if (!acl)
	42	return ERR_PTR(-ENOMEM);
	43	acl_e = acl->a_entries;
	44
	45	for (end = entry + count; entry != end; acl_e++, entry++) {
	46	acl_e->e_tag = le16_to_cpu(entry->e_tag);
	47	acl_e->e_perm = le16_to_cpu(entry->e_perm);
	48
	49	switch(acl_e->e_tag) {
	50	case ACL_USER_OBJ:
	51	case ACL_GROUP_OBJ:
	52	case ACL_MASK:
	53	case ACL_OTHER:
	54	acl_e->e_id = ACL_UNDEFINED_ID;
	55	break;
	56
	57	case ACL_USER:
	58	case ACL_GROUP:
	59	acl_e->e_id = le32_to_cpu(entry->e_id);
	60	break;
	61
	62	default:
	63	goto fail;
	64	}
65	}
66	return acl;
67
68	fail:
69	posix_acl_release(acl);
70	return ERR_PTR(-EINVAL);
71	}
72	EXPORT_SYMBOL (posix_acl_from_xattr);
73
74	/*
75	* Convert from in-memory to extended attribute representation.
76	*/
77	int
78	posix_acl_to_xattr(const struct posix_acl acl, void buffer, size_t size)
79	{
80	posix_acl_xattr_header ext_acl = (posix_acl_xattr_header )buffer;
81	posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
82	int real_size, n;
83
84	real_size = posix_acl_xattr_size(acl->a_count);
85	if (!buffer)
86	return real_size;
87	if (real_size > size)
88	return -ERANGE;
89
90	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
91
92	for (n=0; n < acl->a_count; n++, ext_entry++) {
93	ext_entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
94	ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
95	ext_entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
96	}
97	return real_size;
98	}
99	EXPORT_SYMBOL (posix_acl_to_xattr);