1.\" Copyright 2019 The FreeBSD Foundation. 2.\" 3.\" This software was developed by Bora Ozarslan under sponsorship from 4.\" the FreeBSD Foundation. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' 16.\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd January 22, 2021 30.Dt ELFCTL 1 31.Os 32.Sh NAME 33.Nm elfctl 34.Nd change an ELF binary's feature control note 35.Sh SYNOPSIS 36.Nm 37.Op Fl h | Fl -help 38.Op Fl i 39.Op Fl l 40.Op Fl e Ar featurelist 41.Ar 42.Sh DESCRIPTION 43The 44.Nm 45utility modifies feature flags in the feature control note in an ELF binary. 46.Pp 47The options are as follows: 48.Bl -tag -width indent 49.It Fl h | Fl -help 50Print a usage message and exit. 51.It Fl i 52Ignore unknown feature flags in 53.Ar featurelist . 54.It Fl l 55List known ELF feature flags. 56.It Fl e Ar featurelist 57Edit features from the given comma separated list 58.Ar featurelist . 59.Ar featurelist 60starts with one of the three operations: 61.Dq Li + 62to turn on the features, 63.Dq Li - 64to turn off the features, 65.Dq Li = 66to only turn on the given features. 67A comma separated list of feature names or numeric values follows the 68operation. 69.El 70.Pp 71If 72.Fl e 73is not specified 74.Nm 75displays the status of each feature in the ELF note in each 76.Ar . 77.Sh EXIT STATUS 78Exit status is 0 on success, and 1 if the command 79fails if a file does not exist, is too short, 80or fails to find or edit features note. 81.Sh EXAMPLES 82The following is an example of a typical usage 83of the 84.Nm 85command: 86.Bd -literal -offset indent 87elfctl file 88elfctl -e +aslr file 89.Ed 90.Pp 91Features may be specified as numerical values: 92.Bd -literal -offset -indent 93elfctl -e =0x0001,0x0004 file 94.Ed 95.Pp 96Features may also be specified as a single combined value: 97.Bd -literal -offset -indent 98elfctl -e =0x5 file 99.Ed 100.Sh HISTORY 101.Nm 102first appeared in 103.Fx 12.2 . 104.Sh AUTHORS 105.Nm 106was written by 107.An Bora Ozarslan Mt borako.ozarslan@gmail.com 108under sponsorship from the 109.Fx Foundation. 110