.\" Copyright (C) Andreas Gruenbacher, February 2001

.\" Copyright (C) Silicon Graphics Inc, September 2001

.\"

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.\"

.TH GETXATTR 2 2017-03-13 "Linux" "Linux Programmer's Manual"

.SH NAME

getxattr, lgetxattr, fgetxattr \- retrieve an extended attribute value

.SH SYNOPSIS

.fam C

.nf

.B #include <sys/types.h>

.B #include <sys/xattr.h>

.PP

.BI "ssize_t getxattr(const char\ *" path ", const char\ *" name ,

.BI "                 void\ *" value ", size_t " size );

.BI "ssize_t lgetxattr(const char\ *" path ", const char\ *" name ,

.BI "                 void\ *" value ", size_t " size );

.BI "ssize_t fgetxattr(int " fd ", const char\ *" name ,

.BI "                 void\ *" value ", size_t " size );

.fi

.fam T

.SH DESCRIPTION

Extended attributes are

.IR name :\c

.I value

pairs associated with inodes (files, directories, symbolic links, etc.).

They are extensions to the normal attributes which are associated

with all inodes in the system (i.e., the

.BR stat (2)

data).

A complete overview of extended attributes concepts can be found in

.BR xattr (7).

.PP

.BR getxattr ()

retrieves the value of the extended attribute identified by

.I name

and associated with the given

.I path

in the filesystem.

The attribute value is placed in the buffer pointed to by

.IR value ;

.I size

specifies the size of that buffer.

The return value of the call is the number of bytes placed in

.IR value .

.PP

.BR lgetxattr ()

is identical to

.BR getxattr (),

except in the case of a symbolic link, where the link itself is

interrogated, not the file that it refers to.

.PP

.BR fgetxattr ()

is identical to

.BR getxattr (),

only the open file referred to by

.I fd

(as returned by

.BR open (2))

is interrogated in place of

.IR path .

.PP

An extended attribute

.I name

is a null-terminated string.

The name includes a namespace prefix; there may be several, disjoint

namespaces associated with an individual inode.

The value of an extended attribute is a chunk of arbitrary textual or

binary data that was assigned using

.BR setxattr (2).

.PP

If

.I size

is specified as zero, these calls return the current size of the

named extended attribute (and leave

.I value

unchanged).

This can be used to determine the size of the buffer that

should be supplied in a subsequent call.

(But, bear in mind that there is a possibility that the

attribute value may change between the two calls,

so that it is still necessary to check the return status

from the second call.)

.SH RETURN VALUE

On success, these calls return a nonnegative value which is

the size (in bytes) of the extended attribute value.

On failure, \-1 is returned and

.I errno

is set appropriately.

.SH ERRORS

.TP

.B E2BIG

The size of the attribute value is larger than the maximum size allowed; the

attribute cannot be retrieved.

This can happen on filesystems that support

very large attribute values such as NFSv4, for example.

.TP

.B ENOATTR

The named attribute does not exist, or the process has no access to

this attribute.

.RB ( ENOATTR

is defined to be a synonym for

.BR ENODATA

in

.IR <attr/xattr.h> .)

.TP

.B ENOTSUP

Extended attributes are not supported by the filesystem, or are disabled.

.TP

.B ERANGE

The

.I size

of the

.I value

buffer is too small to hold the result.

.PP

In addition, the errors documented in

.BR stat (2)

can also occur.

.SH VERSIONS

These system calls have been available on Linux since kernel 2.4;

glibc support is provided since version 2.3.

.SH CONFORMING TO

These system calls are Linux-specific.

.\" .SH AUTHORS

.\" Andreas Gruenbacher,

.\" .RI < a.gruenbacher@computer.org >

.\" and the SGI XFS development team,

.\" .RI < linux-xfs@oss.sgi.com >.

.\" Please send any bug reports or comments to these addresses.

.SH EXAMPLE

See

.BR listxattr (2).

.SH SEE ALSO

.BR getfattr (1),

.BR setfattr (1),

.BR listxattr (2),

.BR open (2),

.BR removexattr (2),

.BR setxattr (2),

.BR stat (2),

.BR symlink (7),

.BR xattr (7)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.