mirror of https://github.com/mkerrisk/man-pages
144 lines
4.2 KiB
Groff
144 lines
4.2 KiB
Groff
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.\"
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.\" Extended attributes system calls manual pages
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.\"
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.\" (C) Andreas Gruenbacher, February 2001
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.\" (C) Silicon Graphics Inc, September 2001
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, write to the Free
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.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
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.\" USA.
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.\"
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.TH SETXATTR 2 "Extended Attributes" "Dec 2001" "Linux Programmer's Manual"
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.SH NAME
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setxattr, lsetxattr, fsetxattr \- set an extended attribute value
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.SH SYNOPSIS
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.fam C
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.nf
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.B #include <sys/types.h>
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.B #include <attr/xattr.h>
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.sp
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.BI "int setxattr (const char\ *" path ", const char\ *" name ",
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.BI "\t\t\t const void\ *" value ", size_t " size ", int " flags );
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.BI "int lsetxattr (const char\ *" path ", const char\ *" name ",
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.BI "\t\t\t const void\ *" value ", size_t " size ", int " flags );
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.BI "int fsetxattr (int " filedes ", const char\ *" name ",
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.BI "\t\t\t const void\ *" value ", size_t " size ", int " flags );
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.fi
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.fam T
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.SH DESCRIPTION
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Extended attributes are
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.IR name :\c
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.I value
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pairs associated with inodes (files, directories, symlinks, etc).
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They are extensions to the normal attributes which are associated
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with all inodes in the system (i.e. the
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.BR stat (2)
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data).
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A complete overview of extended attributes concepts can be found in
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.BR attr (5).
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.PP
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.B setxattr
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sets the
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.I value
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of the extended attribute identified by
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.I name
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and associated with the given
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.I path
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in the filesystem.
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The
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.I size
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of the
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.I value
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must be specified.
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.PP
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.B lsetxattr
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is identical to
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.BR setxattr ,
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except in the case of a symbolic link, where the extended attribute is
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set on the link itself, not the file that it refers to.
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.PP
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.B fsetxattr
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is identical to
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.BR setxattr ,
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only the extended attribute is set on the open file pointed to by
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.I filedes
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(as returned by
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.BR open (2))
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in place of
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.IR path .
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.PP
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An extended attribute name is a simple NULL-terminated string.
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The
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.I name
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includes a namespace prefix \- there may be several, disjoint
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namespaces associated with an individual inode.
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The
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.I value
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of an extended attribute is a chunk of arbitrary textual or
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binary data of specified length.
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.PP
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The
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.I flags
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parameter can be used to refine the semantics of the operation.
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XATTR_CREATE specifies a pure create, which fails if the named
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attribute exists already.
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XATTR_REPLACE specifies a pure replace operation, which fails if the
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named attribute does not already exist.
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By default (no flags), the extended attribute will be created if
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need be, or will simply replace the value if the attribute exists.
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.SH RETURN VALUE
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On success, zero is returned.
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On failure, \-1 is returned and
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.I errno
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is set appropriately.
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.PP
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If XATTR_CREATE is specified, and the attribute exists already,
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.I errno
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is set to EEXIST.
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If XATTR_REPLACE is specified, and the attribute does not exist,
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.I errno
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is set to ENOATTR.
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.PP
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If there is insufficient space remaining to store the extended attribute,
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.I errno
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is set to either ENOSPC, or EDQUOT if quota enforcement was the cause.
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.PP
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If extended attributes are not supported by the filesystem, or are disabled,
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.I errno
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is set to ENOTSUP.
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.PP
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The errors documented for the
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.BR stat (2)
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system call are also applicable here.
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.SH AUTHORS
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Andreas Gruenbacher,
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.RI < a.gruenbacher@computer.org >
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and the SGI XFS development team,
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.RI < linux-xfs@oss.sgi.com >.
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Please send any bug reports or comments to these addresses.
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.SH SEE ALSO
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.BR getfattr (1),
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.BR setfattr (1),
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.BR getxattr (2),
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.BR listxattr (2),
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.BR open (2),
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.BR removexattr (2),
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.BR stat (2),
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.BR attr (5)
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