xref: /freebsd/lib/libc/posix1e/extattr.3 (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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2.\" Copyright (c) 2001 Dima Dorfman <dd@FreeBSD.org>
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26.\" $FreeBSD$
27.\"
28.Dd June 24, 2001
29.Dt EXTATTR 3
30.Os
31.Sh NAME
32.Nm extattr_namespace_to_string ,
33.Nm extattr_string_to_namespace
34.Nd convert an extended attribute namespace identifier to a string and
35vice versa
36.Sh LIBRARY
37.Lb libutil
38.Sh SYNOPSIS
39.In sys/extattr.h
40.In libutil.h
41.Ft int
42.Fn extattr_namespace_to_string "int attrnamespace" "char **string"
43.Ft int
44.Fn extattr_string_to_namespace "const char *string" "int *attrnamespace"
45.Sh DESCRIPTION
46The
47.Fn extattr_namespace_to_string
48function converts a VFS extended attribute identifier to a human-readable
49string;
50the
51.Fn extattr_string_to_namespace
52function undoes the aforementioned operation,
53and converts a human-readable string representing a namespace to a
54namespace identifier.
55Although a file system may implement arbitrary namespaces,
56these functions only support the
57.Dv EXTATTR_NAMESPACE_USER
58.Pq Dq user
59and
60.Dv EXTATTR_NAMESPACE_SYSTEM
61.Pq Dq system
62namespaces,
63which are defined in
64.Xr extattr 9 .
65.Pp
66These functions are meant to be used in error reporting and other
67interactive tasks.
68For example,
69instead of printing the integer identifying an extended attribute in
70an error message,
71a program might use
72.Fn extattr_namespace_to_string
73to obtain a human-readable representation.
74Likewise,
75instead of requiring a user to enter the integer representing a namespace,
76an interactive program might ask for a name and use
77.Fn extattr_string_to_namespace
78to get the desired identifier.
79.Sh RETURN VALUES
80If any of the calls are unsuccessful, the value \-1 is returned
81and the global variable
82.Va errno
83is set to indicate the error.
84.Sh ERRORS
85.Bl -tag -width Er
86.It Bq Er EINVAL
87The requested namespace could not be identified.
88.El
89.Sh SEE ALSO
90.Xr extattr 2 ,
91.Xr getextattr 8 ,
92.Xr setextattr 8 ,
93.Xr extattr 9
94.Sh HISTORY
95Extended attribute support was developed as part of the
96.Tn TrustedBSD
97Project, and introduced in
98.Fx 5.0 .
99It was developed to support security extensions requiring additional labels
100to be associated with each file or directory.
101