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@(#)chown.2 8.4 (Berkeley) 4/19/94
.Dd April 19, 1994 .Dt CHOWN 2 .Os BSD 4 .Sh NAME .Nm chown , .Nm fchown .Nd change owner and group of a file .Sh SYNOPSIS .Fd #include <unistd.h> .Ft int .Fn chown "const char *path" "uid_t owner" "gid_t group" .Ft int .Fn fchown "int fd" "uid_t owner" "uid_t group" .Sh DESCRIPTION The owner ID and group ID of the file named by .Fa path or referenced by .Fa fd is changed as specified by the arguments .Fa owner and .Fa group . The owner of a file may change the .Fa group to a group of which he or she is a member, but the change .Fa owner capability is restricted to the super-user.
p .Fn Chown 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.
p .Fn Fchown is particularly useful when used in conjunction with the file locking primitives (see .Xr flock 2 ) .
p One of the owner or group id's may be left unchanged by specifying it as -1. .Sh RETURN VALUES Zero is returned if the operation was successful; -1 is returned if an error occurs, with a more specific error code being placed in the global variable .Va errno . .Sh ERRORS .Fn Chown will fail and the file will be unchanged if: l -tag -width Er t Bq Er ENOTDIR A component of the path prefix is not a directory. t Bq Er EINVAL The pathname contains a character with the high-order bit set. t Bq Er ENAMETOOLONG A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. t Bq Er ENOENT The named file does not exist. t Bq Er EACCES Search permission is denied for a component of the path prefix. t Bq Er ELOOP Too many symbolic links were encountered in translating the pathname. t Bq Er EPERM The effective user ID is not the super-user. t Bq Er EROFS The named file resides on a read-only file system. t Bq Er EFAULT .Fa Path points outside the process's allocated address space. t Bq Er EIO An I/O error occurred while reading from or writing to the file system. .El
p .Fn Fchown will fail if: l -tag -width Er t Bq Er EBADF .Fa Fd does not refer to a valid descriptor. t Bq Er EINVAL .Fa Fd refers to a socket, not a file. t Bq Er EPERM The effective user ID is not the super-user. t Bq Er EROFS The named file resides on a read-only file system. t Bq Er EIO An I/O error occurred while reading from or writing to the file system. .El .Sh SEE ALSO .Xr chown 8 , .Xr chgrp 1 , .Xr chmod 2 , .Xr flock 2 .Sh STANDARDS .Fn Chown is expected to conform to IEEE Std 1003.1-1988
q Dq Tn POSIX . .Sh HISTORY The .Fn fchown function call appeared in x 4.2 .
p The .Fn chown and .Fn fchown functions were changed to follow symbolic links in x 4.4 .