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/*
* linux/fs/xattr_acl.c
*
* Almost all from linux/fs/ext2/acl.c:
* Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfp.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_NOFS);
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);
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