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 IOPERM 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 .BR ioperm ()
  48 sets the port access permission bits for the process for
  49 \fInum\fP bytes starting from port address \fBfrom\fP to the value
  50 \fBturn_on\fP.
  51 If \fBturn_on\fP is non-zero, the calling process must be privileged
  52 .RB ( CAP_SYS_RAWIO ).
  53
  54 Only the first 0x3ff I/O ports can be specified in this manner.
  55 For more ports, the
  56 .BR iopl (2)
  57 system call must be used.
  58 Permissions are not inherited on
  59 .BR fork (2),
  60 but on
  61 .BR execve (2)
  62 they are.
  63 This is useful for giving port access permissions to non-privileged tasks.
  64
  65 This call is mostly for the i386 architecture.
  66 On many other architectures it does not exist or will always
  67 return an error.
  68 .SH "RETURN VALUE"
  69 On success, zero is returned.
  70 On error, \-1 is returned, and
  71 .I errno
  72 is set appropriately.
  73 .SH ERRORS
  74 .TP
  75 .B EINVAL
  76 Invalid values for
  77 .I from
  78 or
  79 .IR num .
  80 .TP
  81 .B EIO
  82 (on ppc) This call is not supported.
  83 .TP
  84 .B ENOMEM
  85 .\" Could not allocate I/O bitmap.
  86 Out of memory.
  87 .TP
  88 .B EPERM
  89 The calling process has insufficient privilege.
  90 .SH "CONFORMING TO"
  91 .BR ioperm ()
  92 is Linux specific and should not be used in programs
  93 intended to be portable.
  94 .SH NOTES
  95 Libc5 treats it as a system call and has a prototype in
  96 .IR <unistd.h> .
  97 Glibc1 does not have a prototype.
  98 Glibc2 has a prototype both in
  99 .I <sys/io.h>
 100 and in
 101 .IR <sys/perm.h> .
 102 Avoid the latter, it is available on i386 only.
 103 .SH "SEE ALSO"
 104 .BR iopl (2),
 105 .BR capabilities (7)