1.\" 2.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.Dd October 7, 2023 27.Dt JEXEC 8 28.Os 29.Sh NAME 30.Nm jexec 31.Nd "execute a command inside an existing jail" 32.Sh SYNOPSIS 33.Nm 34.Op Fl l 35.Op Fl u Ar username | Fl U Ar username 36.Ar jail Op Ar command ... 37.Sh DESCRIPTION 38The 39.Nm 40utility executes 41.Ar command 42inside the 43.Ar jail 44identified by its jid or name. 45If 46.Ar command 47is not specified then the user's shell is used. 48.Pp 49The following options are available: 50.Bl -tag -width indent 51.It Fl l 52Execute in a clean environment. 53The environment is discarded except for 54.Ev HOME , SHELL , TERM , USER , 55and anything from the login class capability database for the user. 56.Ev PATH 57is set to "/bin:/usr/bin". 58.It Fl u Ar username 59The user name from host environment as whom the 60.Ar command 61should run. 62This is the default. 63.It Fl U Ar username 64The user name from jailed environment as whom the 65.Ar command 66should run. 67.El 68.Sh EXAMPLES 69.Ss Example 1 : Open a shell in a jail 70The following command specifies a jail by its name and utilizes the current 71user's shell: 72.Pp 73.Dl # jexec name 74.Pp 75It is also possible to specify a jail by its jid: 76.Pp 77.Dl # jexec JID 78.Ss Example 2 : Run a single command without opening a shell 79The following command runs 80.Ql uname -a 81in a jail called 82.Dq name . 83Since a command is specified explicitly, 84.Nm 85does not spawn an interactive shell. 86Instead, 87.Nm 88executes the specified command directly. 89.Pp 90.Dl # jexec name uname -a 91.Ss Example 3 : Open a shell in a jail with a clean environment 92The following command opens a 93.Xr sh 1 94shell in a jail with a clean environment: 95.Pp 96.Dl # jexec -l name sh 97.Ss Example 4 : Open a shell in a jail with the login command 98The following command utilizes 99.Xr login 1 100to access the jail, submitting an audit record, and displaying the 101user's last login, system copyright, and 102.Xr motd 5 103message: 104.Pp 105.Dl # jexec -l name login -f root 106.Sh SEE ALSO 107.Xr jail_attach 2 , 108.Xr jail 8 , 109.Xr jls 8 110.Sh HISTORY 111The 112.Nm 113utility was added in 114.Fx 5.1 . 115.Sh BUGS 116If the jail is not identified by 117.Ar jid 118there is a possible race in between the lookup of the jail 119and executing the command inside the jail. 120Giving a 121.Ar jid 122has a similar race as another process can stop the jail and 123start another one after the user looked up the 124.Ar jid . 125