io(4) - NetBSD Manual Pages

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IO(4)                NetBSD/i386 Kernel Interfaces Manual                IO(4)


NAME
io -- I/O privilege file
DESCRIPTION
This device is obsolete and is provided for compatibility purposes only; use i386_iopl(2) instead. After opening /dev/io for writing the process is granted full I/O privi- leges; closing the returned file descriptor does not result in revocation of these privileges. The new I/O privileges can be useful in order to write userland programs that handle some hardware directly. The entire access control is handled by the file access permissions of /dev/io, so care should be taken in granting rights for this device. I/O privilege on access to /dev/io is only granted if the kernel was built with the COMPAT_10 option.
FILES
/dev/io
SEE ALSO
mem(4)
HISTORY
The io file appeared in NetBSD 1.0 after it was in the kernel for some time. NetBSD 9.0 January 1, 1996 NetBSD 9.0
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