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 August 12, 2024 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". 58If a user is specified (via 59.Fl u 60or 61.Fl U ) , 62commands are run from that (possibly jailed) user's directory. 63.It Fl u Ar username 64The user name from host environment as whom the 65.Ar command 66should run. 67This is the default. 68.It Fl U Ar username 69The user name from jailed environment as whom the 70.Ar command 71should run. 72.El 73.Sh EXAMPLES 74.Ss Example 1 : Open a shell in a jail 75The following command specifies a jail by its name and utilizes the current 76user's shell: 77.Pp 78.Dl # jexec name 79.Pp 80It is also possible to specify a jail by its jid: 81.Pp 82.Dl # jexec JID 83.Ss Example 2 : Run a single command without opening a shell 84The following command runs 85.Ql uname -a 86in a jail called 87.Dq name . 88Since a command is specified explicitly, 89.Nm 90does not spawn an interactive shell. 91Instead, 92.Nm 93executes the specified command directly. 94.Pp 95.Dl # jexec name uname -a 96.Ss Example 3 : Open a shell in a jail with a clean environment 97The following command opens a 98.Xr sh 1 99shell in a jail with a clean environment: 100.Pp 101.Dl # jexec -l name sh 102.Ss Example 4 : Open a shell in a jail with the login command 103The following command utilizes 104.Xr login 1 105to access the jail, submitting an audit record, and displaying the 106user's last login, system copyright, and 107.Xr motd 5 108message: 109.Pp 110.Dl # jexec -l name login -f root 111.Sh SEE ALSO 112.Xr jail_attach 2 , 113.Xr jail 8 , 114.Xr jls 8 115.Sh HISTORY 116The 117.Nm 118utility was added in 119.Fx 5.1 . 120.Sh BUGS 121If the jail is not identified by 122.Ar jid 123there is a possible race in between the lookup of the jail 124and executing the command inside the jail. 125Giving a 126.Ar jid 127has a similar race as another process can stop the jail and 128start another one after the user looked up the 129.Ar jid . 130