fbbd9655e5
Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
269 lines
6.4 KiB
Groff
269 lines
6.4 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993, 1994
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)chown.2 8.4 (Berkeley) 4/19/94
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd April 10, 2008
|
|
.Dt CHOWN 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm chown ,
|
|
.Nm fchown ,
|
|
.Nm lchown ,
|
|
.Nm fchownat
|
|
.Nd change owner and group of a file
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In unistd.h
|
|
.Ft int
|
|
.Fn chown "const char *path" "uid_t owner" "gid_t group"
|
|
.Ft int
|
|
.Fn fchown "int fd" "uid_t owner" "gid_t group"
|
|
.Ft int
|
|
.Fn lchown "const char *path" "uid_t owner" "gid_t group"
|
|
.Ft int
|
|
.Fn fchownat "int fd" "const char *path" "uid_t owner" "gid_t group" "int flag"
|
|
.Sh DESCRIPTION
|
|
The owner ID and group ID of the file
|
|
named by
|
|
.Fa path
|
|
or referenced by
|
|
.Fa fd
|
|
is changed as specified by the arguments
|
|
.Fa owner
|
|
and
|
|
.Fa group .
|
|
The owner of a file may change the
|
|
.Fa group
|
|
to a group of which
|
|
he or she is a member,
|
|
but the change
|
|
.Fa owner
|
|
capability is restricted to the super-user.
|
|
.Pp
|
|
The
|
|
.Fn chown
|
|
system call
|
|
clears the set-user-id and set-group-id bits
|
|
on the file
|
|
to prevent accidental or mischievous creation of
|
|
set-user-id and set-group-id programs if not executed
|
|
by the super-user.
|
|
The
|
|
.Fn chown
|
|
system call
|
|
follows symbolic links to operate on the target of the link
|
|
rather than the link itself.
|
|
.Pp
|
|
The
|
|
.Fn fchown
|
|
system call
|
|
is particularly useful when used in conjunction
|
|
with the file locking primitives (see
|
|
.Xr flock 2 ) .
|
|
.Pp
|
|
The
|
|
.Fn lchown
|
|
system call is similar to
|
|
.Fn chown
|
|
but does not follow symbolic links.
|
|
.Pp
|
|
The
|
|
.Fn fchownat
|
|
system call is equivalent to the
|
|
.Fn chown
|
|
and
|
|
.Fn lchown
|
|
except in the case where
|
|
.Fa path
|
|
specifies a relative path.
|
|
In this case the file to be changed is determined relative to the directory
|
|
associated with the file descriptor
|
|
.Fa fd
|
|
instead of the current working directory.
|
|
.Pp
|
|
Values for
|
|
.Fa flag
|
|
are constructed by a bitwise-inclusive OR of flags from the following
|
|
list, defined in
|
|
.In fcntl.h :
|
|
.Bl -tag -width indent
|
|
.It Dv AT_SYMLINK_NOFOLLOW
|
|
If
|
|
.Fa path
|
|
names a symbolic link, ownership of the symbolic link is changed.
|
|
.El
|
|
.Pp
|
|
If
|
|
.Fn fchownat
|
|
is passed the special value
|
|
.Dv AT_FDCWD
|
|
in the
|
|
.Fa fd
|
|
parameter, the current working directory is used and the behavior is identical
|
|
to a call to
|
|
.Fn chown
|
|
or
|
|
.Fn lchown
|
|
respectively, depending on whether or not the
|
|
.Dv AT_SYMLINK_NOFOLLOW
|
|
bit is set in the
|
|
.Fa flag
|
|
argument.
|
|
.Pp
|
|
One of the owner or group id's
|
|
may be left unchanged by specifying it as -1.
|
|
.Sh RETURN VALUES
|
|
.Rv -std
|
|
.Sh ERRORS
|
|
The
|
|
.Fn chown
|
|
and
|
|
.Fn lchown
|
|
will fail and the file will be unchanged if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOTDIR
|
|
A component of the path prefix is not a directory.
|
|
.It Bq Er ENAMETOOLONG
|
|
A component of a pathname exceeded 255 characters,
|
|
or an entire path name exceeded 1023 characters.
|
|
.It Bq Er ENOENT
|
|
The named file does not exist.
|
|
.It Bq Er EACCES
|
|
Search permission is denied for a component of the path prefix.
|
|
.It Bq Er ELOOP
|
|
Too many symbolic links were encountered in translating the pathname.
|
|
.It Bq Er EPERM
|
|
The operation would change the ownership, but the effective user ID is not the
|
|
super-user.
|
|
.It Bq Er EPERM
|
|
The named file has its immutable or append-only flag set, see the
|
|
.Xr chflags 2
|
|
manual page for more information.
|
|
.It Bq Er EROFS
|
|
The named file resides on a read-only file system.
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa path
|
|
argument
|
|
points outside the process's allocated address space.
|
|
.It Bq Er EIO
|
|
An I/O error occurred while reading from or writing to the file system.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn fchown
|
|
system call will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
The
|
|
.Fa fd
|
|
argument
|
|
does not refer to a valid descriptor.
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa fd
|
|
argument
|
|
refers to a socket, not a file.
|
|
.It Bq Er EPERM
|
|
The effective user ID is not the super-user.
|
|
.It Bq Er EROFS
|
|
The named file resides on a read-only file system.
|
|
.It Bq Er EIO
|
|
An I/O error occurred while reading from or writing to the file system.
|
|
.El
|
|
.Pp
|
|
In addition to the errors specified for
|
|
.Fn chown
|
|
and
|
|
.Fn lchown ,
|
|
the
|
|
.Fn fchownat
|
|
system call may fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
The
|
|
.Fa path
|
|
argument does not specify an absolute path and the
|
|
.Fa fd
|
|
argument is neither
|
|
.Dv AT_FDCWD
|
|
nor a valid file descriptor open for searching.
|
|
.It Bq Er EINVAL
|
|
The value of the
|
|
.Fa flag
|
|
argument is not valid.
|
|
.It Bq Er ENOTDIR
|
|
The
|
|
.Fa path
|
|
argument is not an absolute path and
|
|
.Fa fd
|
|
is neither
|
|
.Dv AT_FDCWD
|
|
nor a file descriptor associated with a directory.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr chgrp 1 ,
|
|
.Xr chflags 2 ,
|
|
.Xr chmod 2 ,
|
|
.Xr flock 2 ,
|
|
.Xr chown 8
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn chown
|
|
system call is expected to conform to
|
|
.St -p1003.1-90 .
|
|
The
|
|
.Fn fchownat
|
|
system call follows The Open Group Extended API Set 2 specification.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn chown
|
|
function appeared in
|
|
.At v7 .
|
|
The
|
|
.Fn fchown
|
|
system call appeared in
|
|
.Bx 4.2 .
|
|
.Pp
|
|
The
|
|
.Fn chown
|
|
system call was changed to follow symbolic links in
|
|
.Bx 4.4 .
|
|
The
|
|
.Fn lchown
|
|
system call was added in
|
|
.Fx 3.0
|
|
to compensate for the loss of functionality.
|
|
.Pp
|
|
The
|
|
.Fn fchownat
|
|
system call appeared in
|
|
.Fx 8.0 .
|