EXTATTR(3) | NetBSD Library Functions Manual | EXTATTR(3)

# NAME

extattr_namespace_to_string, extattr_string_to_namespace — convert an extended attribute namespace identifier to a string and vice versa extattr_copy_file, extattr_copy_fd, extattr_copy_link, cpxattr, fcpxattr, lcpxattr — copy extended attributes from a file to another one

# LIBRARY

Standard C Library (libc, -lc)

# SYNOPSIS

#include <sys/extattr.h>

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

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

int
extattr_copy_file(const char *from, const char *to, int namespace);

int
extattr_copy_fd(int from_fd, int to_fd, int namespace);

int
extattr_copy_link(const char *from, const char *to, int namespace);

int
cpxattr(const char *from, const char *to);

int
fcpxattr(int from_fd, int to_fd);

int
lcpxattr(const char *from, const char *to);

# DESCRIPTION

The extattr_namespace_to_string() function converts a VFS extended attribute identifier to a human-readable string. The extattr_string_to_namespace() 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.

extattr_copy_file() copies extended attributes of namespace namespace from a file to another one. extattr_copy_fd() does the same using open file descriptors, and extattr_copy_link() does the same as extattr_copy_file() but operates on symbolic links themselves instead of their targets.

cpxattr(), fcpxattr(), and lcpxattr() respectively work the same was as extattr_copy_file(), extattr_copy_fd(), and extattr_copy_link(), but will copy extended attributes from all namespaces accessible to the user, silently skiping unaccessible namespaces.

Please note that none of the extended attribute copying functions are atomic.

# 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.

Extended attribute copying functions may also raise errors produced by extattr_list_file() and extattr_get_file().

# SEE ALSO

getextattr(1), extattr_get_file(2), extattr(9)

# HISTORY

Extended attribute support was developed as part of the TrustedBSD Project, and introduced in FreeBSD 5.0 and NetBSD 3.0. It was developed to support security extensions requiring additional labels to be associated with each file or directory.

January 2, 2004 | NetBSD 5.99