ioperm — set port input/output permissions
#include <sys/io.h> /* for glibc */
int
ioperm( |
unsigned long from, |
| unsigned long num, | |
int turn_on); |
ioperm() sets the port
access permission bits for the calling thread for num bits starting from port
address from. If
turn_on is nonzero,
then permission for the specified bits is enabled; otherwise
it is disabled. If turn_on is nonzero, the calling
thread must be privileged (CAP_SYS_RAWIO).
Before Linux 2.6.8, only the first 0x3ff I/O ports could
be specified in this manner. For more ports, the iopl(2) system call had to
be used (with a level argument of 3). Since
Linux 2.6.8, 65,536 I/O ports can be specified.
Permissions are inherited by the child created by fork(2) (but see NOTES). Permissions are preserved across execve(2); this is useful for giving port access permissions to unprivileged programs.
This call is mostly for the i386 architecture. On many other architectures it does not exist or will always return an error.
On success, zero is returned. On error, −1 is
returned, and errno is set
appropriately.
Invalid values for from or num.
(on PowerPC) This call is not supported.
Out of memory.
The calling thread has insufficient privilege.
ioperm() is Linux-specific
and should not be used in programs intended to be
portable.
The /proc/ioports file shows
the I/O ports that are currently allocated on the system.
Before Linux 2.4, permissions were not inherited by a child created by fork(2).
Glibc has an ioperm()
prototype both in <sys/io.h>
and in <sys/perm.h>
Avoid the latter, it is available on i386 only.
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright (c) 1993 Michael Haardt (michaelmoria.de) Fri Apr 2 11:32:09 MET DST 1993 %%%LICENSE_START(GPLv2+_DOC_FULL) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, see <http://www.gnu.org/licenses/>. %%%LICENSE_END Modified Sat Jul 24 15:12:05 1993 by Rik Faith <faithcs.unc.edu> Modified Tue Aug 1 16:27 1995 by Jochen Karrer <cip307cip.physik.uni-wuerzburg.de> Modified Tue Oct 22 08:11:14 EDT 1996 by Eric S. Raymond <esrthyrsus.com> Modified Mon Feb 15 17:28:41 CET 1999 by Andries E. Brouwer <aebcwi.nl> Modified, 27 May 2004, Michael Kerrisk <mtk.manpagesgmail.com> Added notes on capability requirements |