man2/ioperm.2

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   3 .\" Copyright (c) 1993 Michael Haardt
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   5 .\" Fri Apr  2 11:32:09 MET DST 1993
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  27 .\" Modified Sat Jul 24 15:12:05 1993 by Rik Faith <faith@cs.unc.edu>
  28 .\" Modified Tue Aug  1 16:27    1995 by Jochen Karrer
  29 .\"                              <cip307@cip.physik.uni-wuerzburg.de>
  30 .\" Modified Tue Oct 22 08:11:14 EDT 1996 by Eric S. Raymond <esr@thyrsus.com>
  31 .\" Modified Mon Feb 15 17:28:41 CET 1999 by Andries E. Brouwer <aeb@cwi.nl>
  32 .\" Modified, 27 May 2004, Michael Kerrisk <mtk-manpages@gmx.net>
  33 .\"     Added notes on capability requirements
  34 .\"
  35 .TH IOPERN 2 2004-05-27 "Linux 2.6.6" "Linux Programmer's Manual"
  36 .SH NAME
  37 ioperm \- set port input/output permissions
  38 .SH SYNOPSIS
  39 .B #include <unistd.h>
  40 /* for libc5 */
  41 .br
  42 .B #include <sys/io.h>
  43 /* for glibc */
  44 .sp
  45 .BI "int ioperm(unsigned long " from ", unsigned long " num ", int " turn_on );
  46 .SH DESCRIPTION
  47 \fBIoperm\fP sets the port access permission bits for the process for
  48 \fInum\fP bytes starting from port address \fBfrom\fP to the value
  49 \fBturn_on\fP.  The use of \fBioperm\fP() requires root privileges.
  50
  51 Only the first 0x3ff I/O ports can be specified in this manner.  For more
  52 ports, the
  53 .BR iopl ()
  54 function must be used.
  55 Permissions are not inherited on fork, but on exec they are. This is
  56 useful for giving port access permissions to non-privileged tasks.
  57
  58 This call is mostly for the i386 architecture.
  59 On many other architectures it does not exist or will always
  60 return an error.
  61 .SH "RETURN VALUE"
  62 On success, zero is returned.  On error, \-1 is returned, and
  63 .I errno
  64 is set appropriately.
  65 .SH ERRORS
  66 .TP
  67 .B EINVAL
  68 Invalid values for
  69 .I from
  70 or
  71 .IR num .
  72 .TP
  73 .B EIO
  74 (on ppc) This call is not supported.
  75 .TP
  76 .B EPERM
  77 The calling process has insufficient privilege to call
  78 .BR ioperm ();
  79 the
  80 .B CAP_SYS_RAWIO
  81 capability is required.
  82 .SH "CONFORMING TO"
  83 \fBioperm\fP() is Linux specific and should not be used in programs
  84 intended to be portable.
  85 .SH NOTES
  86 Libc5 treats it as a system call and has a prototype in
  87 .IR <unistd.h> .
  88 Glibc1 does not have a prototype. Glibc2 has a prototype both in
  89 .I <sys/io.h>
  90 and in
  91 .IR <sys/perm.h> .
  92 Avoid the latter, it is available on i386 only.
  93 .SH "SEE ALSO"
  94 .BR iopl (2),
  95 .BR capabilities (7)