/* * 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/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);