CHOWN(2) | System Calls Manual | CHOWN(2) |
chown
, fchown
,
lchown
, fchownat
—
change owner and group of a file
#include
<unistd.h>
int
chown
(const char *path,
uid_t owner, gid_t group);
int
fchown
(int fildes,
uid_t owner, gid_t group);
int
lchown
(const char *path,
uid_t owner, gid_t group);
int
fchownat
(int
fd, const char
*path, uid_t owner,
gid_t group,
int flag);
The owner ID and group ID of the file named by path or referenced by fildes is changed as specified by the arguments owner and group. The owner of a file may change the group to a group of which he or she is a member, but the change owner capability is restricted to the super-user.
The
chown
()
system call clears the set-user-id and set-group-id bits on the file. The
chown
() system call follows symbolic links to
operate on the target of the link rather than the link itself.
The
fchown
()
system call is particularly useful when used in conjunction with the file
locking primitives (see flock(2)).
The
lchown
()
system call is similar to chown
() but does not
follow symbolic links.
The
fchownat
()
system call is equivalent to the chown
() and
lchown
() except in the case where
path specifies a relative path. In this case the file
to be changed is determined relative to the directory associated with the
file descriptor fd instead of the current working
directory.
Values for flag are constructed by a
bitwise-inclusive OR of flags from the following list, defined in
<fcntl.h>
:
AT_SYMLINK_NOFOLLOW
AT_SYMLINK_NOFOLLOW_ANY
If
fchownat
()
is passed the special value AT_FDCWD
in the
fd parameter, the current working directory is used
and the behavior is identical to a call to chown
()
or lchown
() respectively, depending on whether or
not the AT_SYMLINK_NOFOLLOW
bit is set in the
flag argument.
One of the owner or group id's may be left unchanged by specifying it as -1.
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
The chown
() and
lchown
() system calls will fail if:
EACCES
]EFAULT
]ELOOP
]ELOOP
]ENAMETOOLONG
]ENOENT
]ENOTDIR
]The fchown
() system call will fail if:
EBADF
]EINVAL
]Any of these calls will fail if:
EINTR
]EIO
]EPERM
]EROFS
]In addition to the errors specified for
chown
() and lchown
(), the
fchownat
() system call may fail if:
EBADF
]AT_FDCWD
nor a valid file descriptor open for
searching.EINVAL
]ENOTDIR
]AT_FDCWD
nor a
file descriptor associated with a directory.The chown
() system call is expected to
conform to IEEE Std 1003.1-1990
(“POSIX.1”). The fchownat
()
system call is expected to conform to POSIX.1-2008 .
The chown
() function appeared in
Version 7 AT&T UNIX. The
fchown
() system call appeared in
4.2BSD.
The chown
() and
fchown
() system calls were changed to follow
symbolic links in 4.4BSD. The
lchown
() system call was added in
FreeBSD 3.0 to compensate for the loss of
functionality.
The fchownat
() system call appeared in OS
X 10.10
April 19, 1994 | macOS 14.6 |