HP-UX Reference (11i v3 07/02) - 2 System Calls (vol 5)

c
chown(2) chown(2)
NAME
chown(), fchown(), lchown() - change owner and group of a file
SYNOPSIS
#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 fildes, uid_t owner, gid_t group);
DESCRIPTION
The chown() system call changes the user and group ownership of a file. path points to the path name of
a file.
chown() sets the owner ID and group ID of the file to the numeric values contained in owner and
group respectively. A value of
UID_NO_CHANGE
or GID_NO_CHANGE
can be specified in owner or group
to leave unchanged the file’s owner ID or group ID, respectively. Note that owner and group should be less
than
UID_MAX (see limits(5)).
The group ownership of a file can be changed to any group in the current process’s access list or to the real
or effective group ID of the current process. If privilege groups are supported and the user has the
CHOWN
privilege, the file can be given to any group.
If the path given to chown() contains a symbolic link as the last element, this link is traversed and path
name resolution continues. chown() changes the owner and group of the symbolic link’s target, rather
than the owner and group of the link.
The fchown() system call functions exactly like chown(), except that it operates on a file descriptor
instead of a path name. fildes is a file descriptor.
The lchown() system call sets the owner ID and group ID of the named file just as
chown() does,
except in the case where the named file is a symbolic link. In this case,
lchown() changes the owner and
group of the symbolic link file itself.
Access Control Lists - HFS File Systems Only
A user can allow or deny specific individuals and groups access to a file by using the file’s access control list
(see acl(5)). When using
chown() in conjunction with HFS ACLs, if the new owner and/or group does not
have an optional ACL entry corresponding to user
.% and/or %.group in the file’s access control list, the
file’s access permission bits remain unchanged. However, if the new owner and/or group is already desig-
nated by an optional ACL entry of user
.% and/or %.group,
chown() sets the file’s permission bits (and
the three basic ACL entries) to the permissions contained in that entry.
Access Control Lists - JFS File Systems Only
A user can allow or deny specific individuals and groups access to a file by using the file’s access control list
(see aclv(5)). When using
chown() in conjunction with JFS ACLs, if the new owner and/or group of a file
have optional ACL entries corresponding to
user:uid:perm and/or group:gid:perm in the file’s access
control list, those entries remain in the ACL but no longer have any effect, being superseded by the file’s
user::perm and/or group::perm entries.
Security Restrictions
Only processes with an effective user ID equal to the file owner or a user with the OWNER privilege can
change the ownership of a file. If privilege groups are supported, the owner of a file can change the owner-
ship only as a member of a privilege group allowing CHOWN, as set up by the setprivgrp command (see
setprivgrp(1M)). All users get the CHOWN privilege by default.
When a process changes the ownership or group of a file, the file system may clear the set-user-ID and set-
group-ID bits.
See privileges(5) for more information about privileged access on systems that support fine-grained
privileges.
RETURN VALUE
chown() and fchown() return the following values:
0 Successful completion.
-1 Failure. The owner and group of the file remain unchanged. errno is set to indicate the error.
HP-UX 11i Version 3: February 2007 − 1 − Hewlett-Packard Company 65