NAME

extattr_namespace_to_string, extattr_string_to_namespace —

convert an extended attribute namespace identifier to a string and vice versa

LIBRARY

System Utilities Library (libutil, -lutil)

SYNOPSIS

#include <sys/extattr.h>
#include <libutil.h>

int
extattr_namespace_to_string(int attrnamespace, char **string);

int
extattr_string_to_namespace(const char *string, int *attrnamespace);

DESCRIPTION

The extattr_namespace_to_string() function converts a VFS extended attribute identifier to a human-readable string; the extattr_string_to_namespace() function undoes the aforementioned operation, and converts a human-readable string representing a namespace to a namespace identifier. Although a file system may implement arbitrary namespaces, these functions only support the EXTATTR_NAMESPACE_USER (“user”) and EXTATTR_NAMESPACE_SYSTEM (“system”) namespaces, which are defined in extattr(9).

These functions are meant to be used in error reporting and other interactive tasks. For example, instead of printing the integer identifying an extended attribute in an error message, a program might use extattr_namespace_to_string() to obtain a human-readable representation. Likewise, instead of requiring a user to enter the integer representing a namespace, an interactive program might ask for a name and use extattr_string_to_namespace() to get the desired identifier.

RETURN VALUES

If any of the calls are unsuccessful, the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

[EINVAL]: The requested namespace could not be identified.

HISTORY

Extended attribute support was developed as part of the TrustedBSD Project, and introduced in FreeBSD 5.0. It was developed to support security extensions requiring additional labels to be associated with each file or directory.