| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/xattr_acl.c |
| 3 | * |
| 4 | * Almost all from linux/fs/ext2/acl.c: |
| 5 | * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org> |
| 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); |