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chown(2)                    BSD System Calls Manual                   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
     fchown(int fildes, uid_t owner, gid_t group);

     int
     lchown(const char *path, uid_t owner, gid_t group);


DESCRIPTION

     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 to prevent accidental or mischievous creation of set-user-id and
     set-group-id programs if not executed by the super-user.  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 sym-
     bolic links.

     One of the owner or group id's may be left unchanged by specifying it as
     -1.


RETURN VALUES

     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.


ERRORS

     The chown() and lchown() system calls will fail if:

     [EACCES]           Search permission is denied for a component of the
                        path prefix.

     [EFAULT]           The path argument points outside the process's allo-
                        cated address space.

     [ELOOP]            Too many symbolic links are encountered in translating
                        the pathname.  This is taken to be indicative of a
                        looping symbolic link.

     [ENAMETOOLONG]     A component of a pathname exceeded 255 characters, or
                        an entire path name exceeded 1023 characters.

     [ENOENT]           A component of path does not exist.

     [ENOTDIR]          A component of the path prefix is not a directory.

     The fchown() system call will fail if:

     [EBADF]            The fildes argument does not refer to a valid descrip-
                        tor.

     [EINVAL]           The fildes argument refers to a socket, not a file.

     Any of these calls will fail if:

     [EINTR]            Its execution is interrupted by a signal.

     [EIO]              An I/O error occurs while reading from or writing to
                        the file system.

     [EPERM]            The effective user ID does not match the owner of the
                        file and the calling process does not have appropriate
                        (i.e., root) privileges.

     [EROFS]            The named file resides on a read-only file system.


SEE ALSO

     chgrp(1), chmod(2), flock(2), chown(8)


STANDARDS

     The chown() system call is expected to conform to ISO/IEC 9945-1:1990
     (``POSIX.1'').


HISTORY

     The chown() function appeared in Version 7 AT&T UNIX.  The fchown() sys-
     tem 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.

BSD                             April 19, 1994                             BSD

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