CHOWN(2) — UNIX Programmer’s Manual

NAME

chown, fchown − change owner and group of a file

SYNOPSIS

chown(path, owner, group)
char ∗path;
int owner, group;

fchown(fd, owner, group)
int fd, owner, group;

DESCRIPTION

The file which is named by path or referenced by fd has its owner and group changed as specified. Only the super-user may execute this call, because if users were able to give files away, they could defeat the file-space accounting procedures.

On some systems, chown clears the set-user-id and set-group-id bits on the file to prevent accidental creation of set-user-id and set-group-id programs owned by the super-user.

Fchown is particularly useful when used in conjunction with the file locking primitives (see flock(2)).

Only one of the owner and group id’s may be set by specifying the other as −1.

RETURN VALUE

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 errno.

ERRORS

Chown will fail and the file will be unchanged if:

[EINVAL] The argument path does not refer to a file.

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

[ENOENT] The argument pathname is too long.

[EPERM] The argument contains a byte with the high-order bit set.

[ENOENT] The named file does not exist.

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

[EPERM] The effective user ID is not the super-user.

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

[EFAULT] Path points outside the process’s allocated address space.

[ELOOP] Too many symbolic links were encountered in translating the pathname.

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

Fchown will fail if:

[EBADF] Fd does not refer to a valid descriptor.

[EINVAL] Fd refers to a socket, not a file.