1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" from: @(#)fork.2 6.5 (Berkeley) 3/10/91 29.\" $NetBSD: i386_get_ldt.2,v 1.13 2003/08/07 16:42:00 agc Exp $ 30.\" 31.Dd September 20, 1993 32.Dt I386_GET_LDT 2 i386 33.Os 34.Sh NAME 35.Nm i386_get_ldt , 36.Nm i386_set_ldt 37.Nd manage i386 per-process Local Descriptor Table entries 38.Sh LIBRARY 39.Lb libi386 40.Sh SYNOPSIS 41.In sys/types.h 42.In machine/segments.h 43.In machine/sysarch.h 44.Ft int 45.Fn i386_get_ldt "int start_sel" "union descriptor *descs" "int num_sels" 46.Ft int 47.Fn i386_set_ldt "int start_sel" "union descriptor *descs" "int num_sels" 48.Sh DESCRIPTION 49.Fn i386_get_ldt 50will return the list of i386 descriptors that the process has in its 51LDT. 52.Fn i386_set_ldt 53will set a list of i386 descriptors for the current process in its 54LDT. 55Both routines accept a starting selector number 56.Fa start_sel 57, an array of memory that 58will contain the descriptors to be set or returned 59.Fa descs 60, and the number of entries to set or return 61.Fa num_sels . 62.Pp 63The argument 64.Fa descs 65can be either segment_descriptor or gate_descriptor and are defined in 66.Fd \*[Lt]i386/segments.h\*[Gt] . 67These structures are defined by the architecture 68as disjoint bit-fields, so care must be taken in constructing them. 69.Sh RETURN VALUES 70Upon successful completion, 71.Fn i386_get_ldt 72returns the number of descriptors currently in the LDT. 73.Fn i386_set_ldt 74returns the first selector set. 75Otherwise, a value of \-1 is returned and the global 76variable 77.Va errno 78is set to indicate the error. 79.Sh ERRORS 80.Fn i386_get_ldt 81and 82.Fn i386_set_ldt 83will fail if: 84.Bl -tag -width [EINVAL] 85.It Bq Er EINVAL 86An inappropriate parameter was used for 87.Fa start_sel 88or 89.Fa num_sels . 90.It Bq Er EACCES 91The caller attempted to use a descriptor that would 92circumvent protection or cause a failure. 93.El 94.Sh REFERENCES 95i386 Microprocessor Programmer's Reference Manual, Intel 96.Sh WARNING 97You can really hose your process using this. 98