Manual Pages  — REVOKE

revoke – revoke file access

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES ERRORS SEE ALSO HISTORY BUGS

Standard C Library (libc, -lc)

#include <unistd.h>

int
revoke(const char *path);

The revoke() system call invalidates all current open file descriptors in the system for the file named by path. Subsequent operations on any such descriptors fail, with the exceptions that a read() from a character device file which has been revoked returns a count of zero (end of file), and a close() system call will succeed. If the file is a special file for a device which is open, the device close function is called as if all open references to the file had been closed using a special close method which does not block.

Access to a file may be revoked only by its owner or the super user. The revoke() system call is currently supported only for block and character special device files. It is normally used to prepare a terminal device for a new login session, preventing any access by a previous user of the terminal.

The revoke function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

Access to the named file is revoked unless one of the following:

[ENOTDIR]
	A component of the path prefix is not a directory.
[ENAMETOOLONG]
	A component of a pathname exceeded 255 characters, or an entire path name exceeded 1024 characters.
[ENOENT]
	The named file or a component of the path name does not exist.
[EACCES]
	Search permission is denied for a component of the path prefix.
[ELOOP]
	Too many symbolic links were encountered in translating the pathname.
[EFAULT]
	The path argument points outside the process's allocated address space.
[EINVAL]
	The implementation does not support the revoke() operation on the named file.
[EPERM]
	The caller is neither the owner of the file nor the super user.

The revoke() system call first appeared in BSD 4.3 Reno .

The non-blocking close method is only correctly implemented for terminal devices.