1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
154 lines
4.5 KiB
Groff
154 lines
4.5 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)chown.2 8.4 (Berkeley) 4/19/94
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.\" $FreeBSD$
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.\"
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.Dd April 19, 1994
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.Dt CHOWN 2
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.Os BSD 4
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.Sh NAME
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.Nm chown ,
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.Nm fchown
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.Nd change owner and group of a file
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.Sh SYNOPSIS
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.Fd #include <unistd.h>
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.Ft int
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.Fn chown "const char *path" "uid_t owner" "gid_t group"
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.Ft int
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.Fn fchown "int fd" "uid_t owner" "gid_t group"
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.Sh DESCRIPTION
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The owner ID and group ID of the file
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named by
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.Fa path
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or referenced by
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.Fa fd
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is changed as specified by the arguments
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.Fa owner
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and
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.Fa group .
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The owner of a file may change the
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.Fa group
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to a group of which
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he or she is a member,
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but the change
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.Fa owner
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capability is restricted to the super-user.
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.Pp
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.Fn Chown
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clears the set-user-id and set-group-id bits
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on the file
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to prevent accidental or mischievous creation of
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set-user-id and set-group-id programs if not executed
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by the super-user.
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.Pp
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.Fn Fchown
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is particularly useful when used in conjunction
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with the file locking primitives (see
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.Xr flock 2 ) .
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.Pp
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One of the owner or group id's
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may be left unchanged by specifying it as -1.
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.Sh RETURN VALUES
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Zero is returned if the operation was successful;
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-1 is returned if an error occurs, with a more specific
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error code being placed in the global variable
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.Va errno .
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.Sh ERRORS
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.Fn Chown
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will fail and the file will be unchanged if:
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.Bl -tag -width Er
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.It Bq Er ENOTDIR
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A component of the path prefix is not a directory.
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.It Bq Er ENAMETOOLONG
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A component of a pathname exceeded 255 characters,
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or an entire path name exceeded 1023 characters.
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.It Bq Er ENOENT
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The named file does not exist.
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.It Bq Er EACCES
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Search permission is denied for a component of the path prefix.
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.It Bq Er ELOOP
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Too many symbolic links were encountered in translating the pathname.
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.It Bq Er EPERM
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The effective user ID is not the super-user.
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.It Bq Er EROFS
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The named file resides on a read-only file system.
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.It Bq Er EFAULT
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.Fa Path
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points outside the process's allocated address space.
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.It Bq Er EIO
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An I/O error occurred while reading from or writing to the file system.
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.El
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.Pp
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.Fn Fchown
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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.Fa Fd
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does not refer to a valid descriptor.
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.It Bq Er EINVAL
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.Fa Fd
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refers to a socket, not a file.
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.It Bq Er EPERM
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The effective user ID is not the super-user.
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.It Bq Er EROFS
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The named file resides on a read-only file system.
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.It Bq Er EIO
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An I/O error occurred while reading from or writing to the file system.
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.El
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.Sh SEE ALSO
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.Xr chown 8 ,
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.Xr chgrp 1 ,
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.Xr chmod 2 ,
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.Xr flock 2
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.Sh STANDARDS
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The
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.Fn chown
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function call is expected to conform to
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.St -p1003.1-90 .
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.Sh HISTORY
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A
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.Fn chown
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function call appeared in
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.At v7 .
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The
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.Fn fchown
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function call
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appeared in
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.Bx 4.2 .
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.Pp
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The
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.Fn chown
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and
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.Fn fchown
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functions were changed to follow symbolic links in
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.Bx 4.4 .
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