CHOWN(2)CHOWN(2)NAME
chown, fchown, lchown - change owner and group of a file
C SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int chown (const char *path, uid_t owner, gid_t group);
int lchown (const char *path, uid_t owner, gid_t group);
int fchown (int fd, uid_t owner, gid_t group);
DESCRIPTION
Path points to a path name naming a file, and fd refers to the file
descriptor associated with a file. The owner ID and group ID of the
named file are set to the numeric values contained in owner and group
respectively. Note that lchown differs from chown in that it does not
follow symbolic links.
Only processes with effective user ID equal to the file owner or super-
user may change the ownership of a file.
However, if the variable restricted_chown is enabled [see intro(2) and
lboot(1M)] then only the super-user can change the owner of the file,
because if users were able to give files away, they could defeat the file
space accounting procedures. The owner of the file may change the group
ownership only to those groups of which he is a member.
If chown, lchown, or fchown is invoked by other than the super-user, the
set-user-ID and set-group-ID bits of the file mode, 04000 and 02000
respectively, will be cleared. Note that this has the side-effect of
disabling mandatory file/record locking.
Either the owner or group ID may be left unchanged by specifying it as
-1.
Upon successful completion, chown, lchown, and fchown mark for update the
st_ctime field [see stat(2)] of the file.
chown, and lchown, will fail and the owner and group of the named file
will remain unchanged if one or more of the following are true:
[ENOTDIR] A component of the path prefix is not a directory.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied on a component of the path
prefix.
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CHOWN(2)CHOWN(2)
[EPERM] The effective user ID does not match the owner of the
file and the effective user ID is not super-user.
[EPERM] restricted_chown is enabled and the effective user ID is
not the super-user.
[EINVAL] The owner or group value is out of the valid range of
-1, MAXUID.
[EROFS] The named file resides on a read-only file system.
[EFAULT] Path points outside the allocated address space of the
process.
[ELOOP] A path name lookup involved too many symbolic links.
[ENAMETOOLONG] The length of path exceeds {PATH_MAX}, or a pathname
component is longer than {NAME_MAX}.
fchown will fail if:
[EBADF] Fd does not refer to a valid descriptor.
[EINVAL] Fd refers to a socket, not a file. The owner or group
value is out of the valid range of -1, MAXUID.
SEE ALSOchown(1), chmod(2), fchmod(2)DIAGNOSTICS
Upon successful completion, a value of 0 is returned. Otherwise, a value
of -1 is returned and errno is set to indicate the error.
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