man2/ioperm.2

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   3 .\" Copyright (c) 1993 Michael Haardt
   4 .\" (michael@moria.de)
   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 \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.
  50 If \fBturn_on\fP is non-zero, the calling process must be privileged
  51 .RB ( CAP_SYS_RAWIO ).
  52
  53 Only the first 0x3ff I/O ports can be specified in this manner.
  54 For more ports, the
  55 .BR iopl ()
  56 function must be used.
  57 Permissions are not inherited on
  58 .BR fork (),
  59 but on
  60 .BR exec ()
  61 they are.
  62 This is useful for giving port access permissions to non-privileged tasks.
  63
  64 This call is mostly for the i386 architecture.
  65 On many other architectures it does not exist or will always
  66 return an error.
  67 .SH "RETURN VALUE"
  68 On success, zero is returned.
  69 On error, \-1 is returned, and
  70 .I errno
  71 is set appropriately.
  72 .SH ERRORS
  73 .TP
  74 .B EINVAL
  75 Invalid values for
  76 .I from
  77 or
  78 .IR num .
  79 .TP
  80 .B EIO
  81 (on ppc) This call is not supported.
  82 .TP
  83 .B ENOMEM
  84 .\" Could not allocate I/O bitmap.
  85 Out of memory.
  86 .TP
  87 .B EPERM
  88 The calling process has insufficient privilege.
  89 .SH "CONFORMING TO"
  90 \fBioperm\fP() is Linux specific and should not be used in programs
  91 intended to be portable.
  92 .SH NOTES
  93 Libc5 treats it as a system call and has a prototype in
  94 .IR <unistd.h> .
  95 Glibc1 does not have a prototype.
  96 Glibc2 has a prototype both in
  97 .I <sys/io.h>
  98 and in
  99 .IR <sys/perm.h> .
 100 Avoid the latter, it is available on i386 only.
 101 .SH "SEE ALSO"
 102 .BR iopl (2),
 103 .BR capabilities (7)