FCHOWN
Section: POSIX Programmer's Manual (3P)
Updated: 2017
Page Index
PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
fchown
--- change owner and group of a file
SYNOPSIS
#include <unistd.h>
int fchown(int fildes, uid_t owner, gid_t group);
DESCRIPTION
The
fchown()
function shall be equivalent to
chown()
except that the file whose owner and group are changed is
specified by the file descriptor
fildes.
RETURN VALUE
Upon successful completion,
fchown()
shall return 0. Otherwise, it shall return -1 and set
errno
to indicate the error.
ERRORS
The
fchown()
function shall fail if:
- EBADF
-
The
fildes
argument is not an open file descriptor.
- EPERM
-
The effective user ID does not match the owner of the file or the
process does not have appropriate privileges and _POSIX_CHOWN_RESTRICTED
indicates that such privilege is required.
- EROFS
-
The file referred to by
fildes
resides on a read-only file system.
The
fchown()
function may fail if:
- EINVAL
-
The owner or group ID is not a value supported by the implementation.
The
fildes
argument refers to a pipe or socket
or an
fattach()-ed
STREAM
and the implementation disallows execution of
fchown()
on a pipe.
- EIO
-
A physical I/O error has occurred.
- EINTR
-
The
fchown()
function was interrupted by a signal which was caught.
The following sections are informative.
EXAMPLES
Changing the Current Owner of a File
The following example shows how to change the owner of a file named
/home/cnd/mod1
to ``jones'' and the group to ``cnd''.
The numeric value for the user ID is obtained by extracting the user ID
from the user database entry associated with ``jones''. Similarly, the
numeric value for the group ID is obtained by extracting the group ID
from the group database entry associated with ``cnd''. This example
assumes the calling program has appropriate privileges.
-
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>
struct passwd *pwd;
struct group *grp;
int fildes;
...
fildes = open("/home/cnd/mod1", O_RDWR);
pwd = getpwnam("jones");
grp = getgrnam("cnd");
fchown(fildes, pwd->pw_uid, grp->gr_gid);
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
chown()
The Base Definitions volume of POSIX.1-2017,
<unistd.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .