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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)fork.2 6.5 (Berkeley) 3/10/91 33.\" $NetBSD: i386_get_ldt.2,v 1.11 2002/10/02 10:39:14 wiz Exp $ 34.\" 35.Dd September 20, 1993 36.Dt I386_GET_LDT 2 i386 37.Os 38.Sh NAME 39.Nm i386_get_ldt , 40.Nm i386_set_ldt 41.Nd manage i386 per-process Local Descriptor Table entries 42.Sh LIBRARY 43.Lb libi386 44.Sh SYNOPSIS 45.Fd #include \*[Lt]sys/types.h\*[Gt] 46.Fd #include \*[Lt]machine/segments.h\*[Gt] 47.Fd #include \*[Lt]machine/sysarch.h\*[Gt] 48.Ft int 49.Fn i386_get_ldt "int start_sel" "union descriptor *descs" "int num_sels" 50.Ft int 51.Fn i386_set_ldt "int start_sel" "union descriptor *descs" "int num_sels" 52.Sh DESCRIPTION 53.Fn i386_get_ldt 54will return the list of i386 descriptors that the process has in its 55LDT. 56.Fn i386_set_ldt 57will set a list of i386 descriptors for the current process in its 58LDT. 59Both routines accept a starting selector number 60.Fa start_sel 61, an array of memory that 62will contain the descriptors to be set or returned 63.Fa descs 64, and the number of entries to set or return 65.Fa num_sels . 66.Pp 67The argument 68.Fa descs 69can be either segment_descriptor or gate_descriptor and are defined in 70.Fd \*[Lt]i386/segments.h\*[Gt] . 71These structures are defined by the architecture 72as disjoint bit-fields, so care must be taken in constructing them. 73.Sh RETURN VALUES 74Upon successful completion, 75.Fn i386_get_ldt 76returns the number of descriptors currently in the LDT. 77.Fn i386_set_ldt 78returns the first selector set. 79Otherwise, a value of \-1 is returned and the global 80variable 81.Va errno 82is set to indicate the error. 83.Sh ERRORS 84.Fn i386_get_ldt 85and 86.Fn i386_set_ldt 87will fail if: 88.Bl -tag -width [EINVAL] 89.It Bq Er EINVAL 90An inappropriate parameter was used for 91.Fa start_sel 92or 93.Fa num_sels . 94.It Bq Er EACCES 95The caller attempted to use a descriptor that would 96circumvent protection or cause a failure. 97.El 98.Sh REFERENCES 99i386 Microprocessor Programmer's Reference Manual, Intel 100.Sh WARNING 101You can really hose your process using this. 102