diff --git a/usr.sbin/jail/jail.8 b/usr.sbin/jail/jail.8
index 6fb5fdfa0623..0e98914795a2 100644
--- a/usr.sbin/jail/jail.8
+++ b/usr.sbin/jail/jail.8
@@ -1,1475 +1,1473 @@
 .\" Copyright (c) 2000, 2003 Robert N. M. Watson
 .\" Copyright (c) 2008-2012 James Gritton
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\"
 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\" $FreeBSD$
-.\"
 .Dd August 26, 2023
 .Dt JAIL 8
 .Os
 .Sh NAME
 .Nm jail
 .Nd "manage system jails"
 .Sh SYNOPSIS
 .Ss From Configuration File
 .Nm
 .Op Fl cm
 .Op Fl dqv
 .Op Fl f Ar conf_file
 .Op Fl p Ar limit
 .Op Ar jail
 .Nm
 .Op Fl r
 .Op Fl qv
 .Op Fl f Ar conf_file
 .Op Fl p Ar limit
 .Op Cm * | Ar jail ...
 .Ss Without Configuration File
 .Nm
 .Op Fl cm
 .Op Fl dhilqv
 .Op Fl J Ar jid_file
 .Op Fl u Ar username
 .Op Fl U Ar username
 .Ar param Ns = Ns Ar value ...
 .Op Cm command Ns = Ns Ar command ...
 .Nm
 .Op Fl rR
 .Op Fl qv
 .Op Cm * | Ar jail ...
 .Ss Show Parameters
 .Nm
 .Op Fl f Ar conf_file
 .Fl e
 .Ar separator
 .Ss Backward Compatibility
 .Nm
 .Op Fl dhilqv
 .Op Fl J Ar jid_file
 .Op Fl u Ar username
 .Op Fl U Ar username
 .Op Fl n Ar jailname
 .Op Fl s Ar securelevel
 .Ar path hostname ip Ns Op Cm \&, Ns Ar ...
 .Ar command ...
 .Sh DESCRIPTION
 The
 .Nm
 utility creates new jails, or modifies or removes existing jails.
 It can also print a list of configured jails and their parameters.
 A jail
 .Pq or Dq prison
 is specified via parameters on the command line, or in the
 .Xr jail.conf 5
 file.
 .Pp
 At least one of the options
 .Fl c ,
 .Fl e ,
 .Fl m
 or
 .Fl r
 must be specified.
 These options are used alone or in combination to describe the operation to
 perform:
 .Bl -tag -width indent
 .It Fl c
 Create a new jail.
 The jail
 .Va jid
 and
 .Va name
 parameters (if specified on the command line)
 must not refer to an existing jail.
 .It Fl e Ar separator
 Exhibit a list of all configured non-wildcard jails and their parameters.
 No jail creation, modification or removal performed if this option is used.
 The
 .Ar separator
 string is used to separate parameters.
 Use
 .Xr jls 8
 utility to list running jails.
 .It Fl m
 Modify an existing jail.
 One of the
 .Va jid
 or
 .Va name
 parameters must exist and refer to an existing jail.
 Some parameters may not be changed on a running jail.
 .It Fl r
 Remove the
 .Ar jail
 specified by jid or name.
 All jailed processes are killed, and all jails that are
 children of this jail are also
 removed.
 .It Fl rc
 Restart an existing jail.
 The jail is first removed and then re-created, as if
 .Dq Nm Fl r
 and
 .Dq Nm Fl c
 were run in succession.
 .It Fl cm
 Create a jail if it does not exist, or modify the jail if it does exist.
 .It Fl mr
 Modify an existing jail.
 The jail may be restarted if necessary to modify parameters than could
 not otherwise be changed.
 .It Fl cmr
 Create a jail if it doesn't exist, or modify (and possibly restart) the
 jail if it does exist.
 .El
 .Pp
 Other available options are:
 .Bl -tag -width indent
 .It Fl d
 Allow making changes to a dying jail, equivalent to the
 .Va allow.dying
 parameter.
 .It Fl f Ar conf_file
 Use configuration file
 .Ar conf_file
 instead of the default
 .Pa /etc/jail.conf .
 .It Fl h
 Resolve the
 .Va host.hostname
 parameter (or
 .Va hostname )
 and add all IP addresses returned by the resolver
 to the list of addresses for this jail.
 This is equivalent to the
 .Va ip_hostname
 parameter.
 .It Fl i
 Output (only) the jail identifier of the newly created jail(s).
 This implies the
 .Fl q
 option.
 .It Fl J Ar jid_file
 Write a
 .Ar jid_file
 file, containing the parameters used to start the jail.
 .It Fl l
 Run commands in a clean environment.
 This is deprecated and is equivalent to the exec.clean parameter.
 .It Fl n Ar jailname
 Set the jail's name.
 This is deprecated and is equivalent to the
 .Va name
 parameter.
 .It Fl p Ar limit
 Limit the number of commands from
 .Va  exec.*
 that can run simultaneously.
 .It Fl q
 Suppress the message printed whenever a jail is created, modified or removed.
 Only error messages will be printed.
 .It Fl R
 A variation of the
 .Fl r
 option that removes an existing jail without using the configuration file.
 No removal-related parameters for this jail will be used \(em the jail will
 simply be removed.
 .It Fl s Ar securelevel
 Set the
 .Va kern.securelevel
 MIB entry to the specified value inside the newly created jail.
 This is deprecated and is equivalent to the
 .Va securelevel
 parameter.
 .It Fl u Ar username
 The user name from host environment as whom jailed commands should run.
 This is deprecated and is equivalent to the
 .Va exec.jail_user
 and
 .Va exec.system_jail_user
 parameters.
 .It Fl U Ar username
 The user name from the jailed environment as whom jailed commands should run.
 This is deprecated and is equivalent to the
 .Va exec.jail_user
 parameter.
 .It Fl v
 Print a message on every operation, such as running commands and
 mounting filesystems.
 .El
 .Pp
 If no arguments are given after the options, the operation (except
 remove) will be performed on all jails specified in the
 .Xr jail.conf 5
 file.
 A single argument of a jail name will operate only on the specified jail.
 The
 .Fl r
 and
 .Fl R
 options can also remove running jails that aren't in the
 .Xr jail.conf 5
 file, specified by name or jid.
 .Pp
 An argument of
 .Dq *
 is a wildcard that will operate on all jails, regardless of whether
 they appear in
 .Xr jail.conf 5 ;
 this is the surest way for
 .Fl r
 to remove all jails.
 If hierarchical jails exist, a partial-matching wildcard definition may
 be specified.
 For example, an argument of
 .Dq foo.*
 would apply to jails with names like
 .Dq foo.bar
 and
 .Dq foo.bar.baz .
 .Pp
 A jail may also be specified via parameters directly on the command line in
 .Dq name=value
 form, ignoring the contents of
 .Xr jail.conf 5 .
 For backward compatibility, the command line may also have four fixed
 parameters, without names:
 .Ar path ,
 .Ar hostname ,
 .Ar ip ,
 and
 .Ar command .
 .Ss Jail Parameters
 Parameters in the
 .Xr jail.conf 5
 file, or on the command line, are generally of the form
 .Dq name=value .
 Some parameters are boolean, and do not have a value but are set by the
 name alone with or without a
 .Dq no
 prefix, e.g.
 .Va persist
 or
 .Va nopersist .
 They can also be given the values
 .Dq true
 and
 .Dq false .
 Other parameters may have more than one value, specified as a
 comma-separated list or with
 .Dq +=
 in the configuration file (see
 .Xr jail.conf 5
 for details).
 .Pp
 The
 .Nm
 utility recognizes two classes of parameters.
 There are the true jail
 parameters that are passed to the kernel when the jail is created,
 which can be seen with
 .Xr jls 8 ,
 and can (usually) be changed with
 .Dq Nm Fl m .
 Then there are pseudo-parameters that are only used by
 .Nm
 itself.
 .Pp
 Jails have a set of core parameters, and kernel modules can add their own
 jail parameters.
 The current set of available parameters can be retrieved via
 .Dq Nm sysctl Fl d Va security.jail.param .
 Any parameters not set will be given default values, often based on the
 current environment.
 The core parameters are:
 .Bl -tag -width indent
 .It Va jid
 The jail identifier.
 This will be assigned automatically to a new jail (or can be explicitly
 set), and can be used to identify the jail for later modification, or
 for such commands as
 .Xr jls 8
 or
 .Xr jexec 8 .
 .It Va name
 The jail name.
 This is an arbitrary string that identifies a jail (except it may not
 contain a
 .Sq \&. ) .
 Like the
 .Va jid ,
 it can be passed to later
 .Nm
 commands, or to
 .Xr jls 8
 or
 .Xr jexec 8 .
 If no
 .Va name
 is supplied, a default is assumed that is the same as the
 .Va jid .
 The
 .Va name
 parameter is implied by the
 .Xr jail.conf 5
 file format, and need not be explicitly set when using the configuration
 file.
 .It Va path
 The directory which is to be the root of the jail.
 Any commands run inside the jail, either by
 .Nm
 or from
 .Xr jexec 8 ,
 are run from this directory.
 .It Va ip4.addr
 A list of IPv4 addresses assigned to the jail.
 If this is set, the jail is restricted to using only these addresses.
 Any attempts to use other addresses fail, and attempts to use wildcard
 addresses silently use the jailed address instead.
 For IPv4 the first address given will be used as the source address
 when source address selection on unbound sockets cannot find a better
 match.
 It is only possible to start multiple jails with the same IP address
 if none of the jails has more than this single overlapping IP address
 assigned to itself.
 .It Va ip4.saddrsel
 A boolean option to change the formerly mentioned behaviour and disable
 IPv4 source address selection for the jail in favour of the primary
 IPv4 address of the jail.
 Source address selection is enabled by default for all jails and the
 .Va ip4.nosaddrsel
 setting of a parent jail is not inherited for any child jails.
 .It Va ip4
 Control the availability of IPv4 addresses.
 Possible values are
 .Dq inherit
 to allow unrestricted access to all system addresses,
 .Dq new
 to restrict addresses via
 .Va ip4.addr ,
 and
 .Dq disable
 to stop the jail from using IPv4 entirely.
 Setting the
 .Va ip4.addr
 parameter implies a value of
 .Dq new .
 .It Va ip6.addr , Va ip6.saddrsel , Va ip6
 A set of IPv6 options for the jail, the counterparts to
 .Va ip4.addr ,
 .Va ip4.saddrsel
 and
 .Va ip4
 above.
 .It Va vnet
 Create the jail with its own virtual network stack,
 with its own network interfaces, addresses, routing table, etc.
 The kernel must have been compiled with the
 .Sy VIMAGE option
 for this to be available.
 Possible values are
 .Dq inherit
 to use the system network stack, possibly with restricted IP addresses,
 and
 .Dq new
 to create a new network stack.
 .It Va host.hostname
 The hostname of the jail.
 Other similar parameters are
 .Va host.domainname ,
 .Va host.hostuuid
 and
 .Va host.hostid .
 .It Va host
 Set the origin of hostname and related information.
 Possible values are
 .Dq inherit
 to use the system information and
 .Dq new
 for the jail to use the information from the above fields.
 Setting any of the above fields implies a value of
 .Dq new .
 .It Va securelevel
 The value of the jail's
 .Va kern.securelevel
 sysctl.
 A jail never has a lower securelevel than its parent system, but by
 setting this parameter it may have a higher one.
 If the system securelevel is changed, any jail securelevels will be at
 least as secure.
 .It Va devfs_ruleset
 The number of the devfs ruleset that is enforced for mounting devfs in
 this jail.
 A value of zero (default) means no ruleset is enforced.
 Descendant jails inherit the parent jail's devfs ruleset enforcement.
 Mounting devfs inside a jail is possible only if the
 .Va allow.mount
 and
 .Va allow.mount.devfs
 permissions are effective and
 .Va enforce_statfs
 is set to a value lower than 2.
 Devfs rules and rulesets cannot be viewed or modified from inside a jail.
 .Pp
 NOTE: It is important that only appropriate device nodes in devfs be
 exposed to a jail; access to disk devices in the jail may permit processes
 in the jail to bypass the jail sandboxing by modifying files outside of
 the jail.
 See
 .Xr devfs 8
 for information on how to use devfs rules to limit access to entries
 in the per-jail devfs.
 A simple devfs ruleset for jails is available as ruleset #4 in
 .Pa /etc/defaults/devfs.rules .
 .It Va children.max
 The number of child jails allowed to be created by this jail (or by
 other jails under this jail).
 This limit is zero by default, indicating the jail is not allowed to
 create child jails.
 See the
 .Sx "Hierarchical Jails"
 section for more information.
 .It Va children.cur
 The number of descendants of this jail, including its own child jails
 and any jails created under them.
 .It Va enforce_statfs
 This determines what information processes in a jail are able to get
 about mount points.
 It affects the behaviour of the following syscalls:
 .Xr statfs 2 ,
 .Xr fstatfs 2 ,
 .Xr getfsstat 2 ,
 and
 .Xr fhstatfs 2
 (as well as similar compatibility syscalls).
 When set to 0, all mount points are available without any restrictions.
 When set to 1, only mount points below the jail's chroot directory are
 visible.
 In addition to that, the path to the jail's chroot directory is removed
 from the front of their pathnames.
 When set to 2 (default), above syscalls can operate only on a mount-point
 where the jail's chroot directory is located.
 .It Va persist
 Setting this boolean parameter allows a jail to exist without any
 processes.
 Normally, a command is run as part of jail creation, and then the jail
 is destroyed as its last process exits.
 A new jail must have either the
 .Va persist
 parameter or
 .Va exec.start
 or
 .Va command
 pseudo-parameter set.
 .It Va cpuset.id
 The ID of the cpuset associated with this jail (read-only).
 .It Va dying
 This is true if the jail is in the process of shutting down (read-only).
 .It Va parent
 The
 .Va jid
 of the parent of this jail, or zero if this is a top-level jail
 (read-only).
 .It Va osrelease
 The string for the jail's
 .Va kern.osrelease
 sysctl and uname -r.
 .It Va osreldate
 The number for the jail's
 .Va kern.osreldate
 and uname -K.
 .It Va allow.*
 Some restrictions of the jail environment may be set on a per-jail
 basis.
 With the exception of
 .Va allow.set_hostname
 and
 .Va allow.reserved_ports ,
 these boolean parameters are off by default.
 .Bl -tag -width indent
 .It Va allow.set_hostname
 The jail's hostname may be changed via
 .Xr hostname 1
 or
 .Xr sethostname 3 .
 .It Va allow.sysvipc
 A process within the jail has access to System V IPC primitives.
 This is deprecated in favor of the per-module parameters (see below).
 When this parameter is set, it is equivalent to setting
 .Va sysvmsg ,
 .Va sysvsem ,
 and
 .Va sysvshm
 all to
 .Dq inherit .
 .It Va allow.raw_sockets
 The jail root is allowed to create raw sockets.
 Setting this parameter allows utilities like
 .Xr ping 8
 and
 .Xr traceroute 8
 to operate inside the jail.
 If this is set, the source IP addresses are enforced to comply
 with the IP address bound to the jail, regardless of whether or not
 the
 .Dv IP_HDRINCL
 flag has been set on the socket.
 Since raw sockets can be used to configure and interact with various
 network subsystems, extra caution should be used where privileged access
 to jails is given out to untrusted parties.
 .It Va allow.chflags
 Normally, privileged users inside a jail are treated as unprivileged by
 .Xr chflags 2 .
 When this parameter is set, such users are treated as privileged, and
 may manipulate system file flags subject to the usual constraints on
 .Va kern.securelevel .
 .It Va allow.mount
 privileged users inside the jail will be able to mount and unmount file
 system types marked as jail-friendly.
 The
 .Xr lsvfs 1
 command can be used to find file system types available for mount from
 within a jail.
 This permission is effective only if
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.devfs
 privileged users inside the jail will be able to mount and unmount the
 devfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 The devfs ruleset should be restricted from the default by using the
 .Va devfs_ruleset
 option.
 .It Va allow.quotas
 The jail root may administer quotas on the jail's filesystem(s).
 This includes filesystems that the jail may share with other jails or
 with non-jailed parts of the system.
 .It Va allow.read_msgbuf
 Jailed users may read the kernel message buffer.
 If the
 .Va security.bsd.unprivileged_read_msgbuf
 MIB entry is zero, this will be restricted to the root user.
 .It Va allow.socket_af
 Sockets within a jail are normally restricted to IPv4, IPv6, local
 (UNIX), and route.  This allows access to other protocol stacks that
 have not had jail functionality added to them.
 .It Va allow.mlock
 Locking or unlocking physical pages in memory are normally not available
 within a jail.
 When this parameter is set, users may
 .Xr mlock 2
 or
 .Xr munlock 2
 memory subject to
 .Va security.bsd.unprivileged_mlock
 and resource limits.
 .It Va allow.nfsd
 The
 .Xr mountd 8 ,
 .Xr nfsd 8 ,
 .Xr nfsuserd 8 ,
 .Xr gssd 8
 and
 .Xr rpc.tlsservd 8
 daemons are permitted to run inside a properly configured vnet-enabled jail.
 The jail's root must be a file system mount point and
 .Va enforce_statfs
 must not be set to 0, so that
 .Xr mountd 8
 can export file systems visible within the jail.
 .Va enforce_statfs
 must be set to 1 if file systems mounted under the
 jail's file system need to be exported by
 .Xr mount 8 .
 For exporting only the jail's file system, a setting of 2
 is sufficient.
 If the kernel configuration does not include the
 .Sy NFSD
 option,
 .Pa nfsd.ko
 must be loaded outside of the jails.
 This is normally done by adding
 .Dq nfsd
 to
 .Va kld_list
 in the
 .Xr rc.conf 5
 file outside of the jails.
 Similarily, if the
 .Xr gssd 8
 is to be run in a jail, either the kernel
 .Sy KGSSAPI
 option needs to be specified or
 .Dq kgssapi
 and
 .Dq kgssapi_krb5
 need to be in
 .Va kld_list
 in the
 .Xr rc.conf 5
 file outside of the jails.
 .It Va allow.reserved_ports
 The jail root may bind to ports lower than 1024.
 .It Va allow.unprivileged_proc_debug
 Unprivileged processes in the jail may use debugging facilities.
 .It Va allow.suser
 The value of the jail's
 .Va security.bsd.suser_enabled
 sysctl.
 The super-user will be disabled automatically if its parent system has it
 disabled.
 The super-user is enabled by default.
 .El
 .El
 .Pp
 Kernel modules may add their own parameters, which only exist when the
 module is loaded.
 These are typically headed under a parameter named after the module,
 with values of
 .Dq inherit
 to give the jail full use of the module,
 .Dq new
 to encapsulate the jail in some module-specific way,
 and
 .Dq disable
 to make the module unavailable to the jail.
 There also may be other parameters to define jail behavior within the module.
 Module-specific parameters include:
 .Bl -tag -width indent
 .It Va allow.mount.fdescfs
 privileged users inside the jail will be able to mount and unmount the
 fdescfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.fusefs
 privileged users inside the jail will be able to mount and unmount 
 fuse-based file systems.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.nullfs
 privileged users inside the jail will be able to mount and unmount the
 nullfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.procfs
 privileged users inside the jail will be able to mount and unmount the
 procfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.linprocfs
 privileged users inside the jail will be able to mount and unmount the
 linprocfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.linsysfs
 privileged users inside the jail will be able to mount and unmount the
 linsysfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.tmpfs
 privileged users inside the jail will be able to mount and unmount the
 tmpfs file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 .It Va allow.mount.zfs
 privileged users inside the jail will be able to mount and unmount the
 ZFS file system.
 This permission is effective only together with
 .Va allow.mount
 and only when
 .Va enforce_statfs
 is set to a value lower than 2.
 See
 .Xr zfs 8
 for information on how to configure the ZFS filesystem to operate from
 within a jail.
 .It Va allow.vmm
 The jail may access
 .Xr vmm 4 .
 This flag is only available when the
 .Xr vmm 4
 kernel module is loaded.
 .It Va linux
 Determine how a jail's Linux emulation environment appears.
 A value of
 .Dq inherit
 will keep the same environment, and
 .Dq new
 will give the jail its own environment (still originally inherited when
 the jail is created).
 .It Va linux.osname , linux.osrelease , linux.oss_version
 The Linux OS name, OS release, and OSS version associated with this jail.
 .It Va sysvmsg
 Allow access to SYSV IPC message primitives.
 If set to
 .Dq inherit ,
 all IPC objects on the system are visible to this jail, whether they
 were created by the jail itself, the base system, or other jails.
 If set to
 .Dq new ,
 the jail will have its own key namespace, and can only see the objects
 that it has created;
 the system (or parent jail) has access to the jail's objects, but not to
 its keys.
 If set to
 .Dq disable ,
 the jail cannot perform any sysvmsg-related system calls.
 .It Va sysvsem, sysvshm
 Allow access to SYSV IPC semaphore and shared memory primitives, in the
 same manner as
 .Va sysvmsg.
 .El
 .Pp
 There are pseudo-parameters that are not passed to the kernel, but are
 used by
 .Nm
 to set up the jail environment, often by running specified commands
 when jails are created or removed.
 The
 .Va exec.*
 command parameters are
 .Xr sh 1
 command lines that are run in either the system or jail environment.
 They may be given multiple values, which would run the specified
 commands in sequence.
 All commands must succeed (return a zero exit status), or the jail will
 not be created or removed, as appropriate.
 .Pp
 The pseudo-parameters are:
 .Bl -tag -width indent
 .It Va exec.prepare
 Command(s) to run in the system environment to prepare a jail for creation.
 These commands are executed before assigning IP addresses and mounting
 filesystems, so they may be used to create a new jail filesystem if it does
 not already exist.
 .It Va exec.prestart
 Command(s) to run in the system environment before a jail is created.
 .It Va exec.created
 Command(s) to run in the system environment right after a jail has been
 created, but before commands (or services) get executed in the jail.
 .It Va exec.start
 Command(s) to run in the jail environment when a jail is created.
 A typical command to run is
 .Dq sh /etc/rc .
 .It Va command
 A synonym for
 .Va exec.start
 for use when specifying a jail directly on the command line.
 Unlike other parameters whose value is a single string,
 .Va command
 uses the remainder of the
 .Nm
 command line as its own arguments.
 .It Va exec.poststart
 Command(s) to run in the system environment after a jail is created,
 and after any
 .Va exec.start
 commands have completed.
 .It Va exec.prestop
 Command(s) to run in the system environment before a jail is removed.
 .It Va exec.stop
 Command(s) to run in the jail environment before a jail is removed,
 and after any
 .Va exec.prestop
 commands have completed.
 A typical command to run is
 .Dq sh /etc/rc.shutdown jail .
 .It Va exec.poststop
 Command(s) to run in the system environment after a jail is removed.
 .It Va exec.release
 Command(s) to run in the system environment after all other actions are done.
 These commands are executed after unmounting filesystems and removing IP
 addresses, so they may be used to remove a jail filesystem if it is no longer
 needed.
 .It Va exec.clean
 Run commands in a clean environment.
 The environment is discarded except for
 .Ev HOME , SHELL , TERM
 and
 .Ev USER .
 .Ev HOME
 and
 .Ev SHELL
 are set to the target login's default values.
 .Ev USER
 is set to the target login.
 .Ev TERM
 is imported from the current environment.
 The environment variables from the login class capability database for the
 target login are also set.
 .It Va exec.jail_user
 The user to run commands as, when running in the jail environment.
 The default is to run the commands as the current user.
 .It Va exec.system_jail_user
 This boolean option looks for the
 .Va exec.jail_user
 in the system
 .Xr passwd 5
 file, instead of in the jail's file.
 .It Va exec.system_user
 The user to run commands as, when running in the system environment.
 The default is to run the commands as the current user.
 .It Va exec.timeout
 The maximum amount of time to wait for a command to complete, in
 seconds.
 If a command is still running after this timeout has passed,
 the jail will not be created or removed, as appropriate.
 .It Va exec.consolelog
 A file to direct command output (stdout and stderr) to.
 .It Va exec.fib
 The FIB (routing table) to set when running commands inside the jail.
 .It Va stop.timeout
 The maximum amount of time to wait for a jail's processes to exit
 after sending them a
 .Dv SIGTERM
 signal (which happens after the
 .Va exec.stop
 commands have completed).
 After this many seconds have passed, the jail will be removed, which
 will kill any remaining processes.
 If this is set to zero, no
 .Dv SIGTERM
 is sent and the jail is immediately removed.
 The default is 10 seconds.
 .It Va interface
 A network interface to add the jail's IP addresses
 .Va ( ip4.addr
 and
 .Va ip6.addr )
 to.
 An alias for each address will be added to the interface before the
 jail is created, and will be removed from the interface after the
 jail is removed.
 .It Va ip4.addr
 In addition to the IP addresses that are passed to the kernel, an
 interface, netmask and additional parameters (as supported by
 .Xr ifconfig 8 Ns )
 may also be specified, in the form
 .Dq Ar interface Ns | Ns Ar ip-address Ns / Ns Ar netmask param ... .
 If an interface is given before the IP address, an alias for the address
 will be added to that interface, as it is with the
 .Va interface
 parameter.
 If a netmask in either dotted-quad or CIDR form is given
 after an IP address, it will be used when adding the IP alias.
 If additional parameters are specified then they will also be used when
 adding the IP alias.
 .It Va ip6.addr
 In addition to the IP addresses that are passed to the kernel,
 an interface, prefix and additional parameters (as supported by
 .Xr ifconfig 8 Ns )
 may also be specified, in the form
 .Dq Ar interface Ns | Ns Ar ip-address Ns / Ns Ar prefix param ... .
 .It Va vnet.interface
 A network interface to give to a vnet-enabled jail after is it created.
 The interface will automatically be released when the jail is removed.
 .It Va ip_hostname
 Resolve the
 .Va host.hostname
 parameter and add all IP addresses returned by the resolver
 to the list of addresses
 .Po Va ip4.addr
 or
 .Va ip6.addr Pc
 for this jail.
 This may affect default address selection for outgoing IPv4 connections
 from jails.
 The address first returned by the resolver for each address family
 will be used as the primary address.
 .It Va mount
 A filesystem to mount before creating the jail (and to unmount after
 removing it), given as a single
 .Xr fstab 5
 line.
 .It Va mount.fstab
 An
 .Xr fstab 5
 format file containing filesystems to mount before creating a jail.
 .It Va mount.devfs
 Mount a
 .Xr devfs 5
 filesystem on the chrooted
 .Pa /dev
 directory, and apply the ruleset in the
 .Va devfs_ruleset
 parameter (or a default of ruleset 4: devfsrules_jail)
 to restrict the devices visible inside the jail.
 .It Va mount.fdescfs
 Mount a
 .Xr fdescfs 5
 filesystem on the chrooted
 .Pa /dev/fd
 directory.
 .It Va mount.procfs
 Mount a
 .Xr procfs 5
 filesystem on the chrooted
 .Pa /proc
 directory.
 .It Va allow.dying
 Allow making changes to a
 .Va dying
 jail.
 .It Va depend
 Specify a jail (or jails) that this jail depends on.
 When this jail is to be created, any jail(s) it depends on must already exist.
 If not, they will be created automatically, up to the completion of the last
 .Va exec.poststart
 command, before any action will taken to create this jail.
 When jails are removed the opposite is true:
 this jail will be removed, up to the last
 .Va exec.poststop
 command, before any jail(s) it depends on are stopped.
 .El
 .Sh EXAMPLES
 Jails are typically set up using one of two philosophies: either to
 constrain a specific application (possibly running with privilege), or
 to create a
 .Dq "virtual system image"
 running a variety of daemons and services.
 In both cases, a fairly complete file system install of
 .Fx
 is
 required, so as to provide the necessary command line tools, daemons,
 libraries, application configuration files, etc.
 However, for a virtual server configuration, a fair amount of
 additional work is required so as to replace the
 .Dq boot
 process.
 This manual page documents the configuration steps necessary to support
 either of these steps, although the configuration steps may need to be
 refined based on local requirements.
 .Ss "Setting up a Jail Directory Tree"
 To set up a jail directory tree containing an entire
 .Fx
 distribution, the following
 .Xr sh 1
 command script can be used:
 .Bd -literal -offset indent
 D=/here/is/the/jail
 cd /usr/src
 mkdir -p $D
 make world DESTDIR=$D
 make distribution DESTDIR=$D
 .Ed
 .Pp
 In many cases this example would put far more in the jail than needed.
 In the other extreme case a jail might contain only one file:
 the executable to be run in the jail.
 .Pp
 We recommend experimentation, and caution that it is a lot easier to
 start with a
 .Dq fat
 jail and remove things until it stops working,
 than it is to start with a
 .Dq thin
 jail and add things until it works.
 .Ss "Setting Up a Jail"
 Do what was described in
 .Sx "Setting Up a Jail Directory Tree"
 to build the jail directory tree.
 For the sake of this example, we will
 assume you built it in
 .Pa /data/jail/testjail ,
 for a jail named
 .Dq testjail .
 Substitute below as needed with your
 own directory, IP address, and hostname.
 .Ss "Setting up the Host Environment"
 First, set up the real system's environment to be
 .Dq jail-friendly .
 For consistency, we will refer to the parent box as the
 .Dq "host environment" ,
 and to the jailed virtual machine as the
 .Dq "jail environment" .
 Since jails are implemented using IP aliases, one of the first things to do
 is to disable IP services on the host system that listen on all local
 IP addresses for a service.
 If a network service is present in the host environment that binds all
 available IP addresses rather than specific IP addresses, it may service
 requests sent to jail IP addresses if the jail did not bind the port.
 This means changing
 .Xr inetd 8
 to only listen on the
 appropriate IP address, and so forth.
 Add the following to
 .Pa /etc/rc.conf
 in the host environment:
 .Bd -literal -offset indent
 sendmail_enable="NO"
 inetd_flags="-wW -a 192.0.2.23"
 rpcbind_enable="NO"
 .Ed
 .Pp
 .Li 192.0.2.23
 is the native IP address for the host system, in this example.
 Daemons that run out of
 .Xr inetd 8
 can be easily configured to use only the specified host IP address.
 Other daemons
 will need to be manually configured \(em for some this is possible through
 .Xr rc.conf 5
 flags entries; for others it is necessary to modify per-application
 configuration files, or to recompile the application.
 The following frequently deployed services must have their individual
 configuration files modified to limit the application to listening
 to a specific IP address:
 .Pp
 To configure
 .Xr sshd 8 ,
 it is necessary to modify
 .Pa /etc/ssh/sshd_config .
 .Pp
 To configure
 .Xr sendmail 8 ,
 it is necessary to modify
 .Pa /etc/mail/sendmail.cf .
 .Pp
 In addition, a number of services must be recompiled in order to run
 them in the host environment.
 This includes most applications providing services using
 .Xr rpc 3 ,
 such as
 .Xr rpcbind 8 ,
 .Xr nfsd 8 ,
 and
 .Xr mountd 8 .
 In general, applications for which it is not possible to specify which
 IP address to bind should not be run in the host environment unless they
 should also service requests sent to jail IP addresses.
 Attempting to serve
 NFS from the host environment may also cause confusion, and cannot be
 easily reconfigured to use only specific IPs, as some NFS services are
 hosted directly from the kernel.
 Any third-party network software running
 in the host environment should also be checked and configured so that it
 does not bind all IP addresses, which would result in those services also
 appearing to be offered by the jail environments.
 .Pp
 Once
 these daemons have been disabled or fixed in the host environment, it is
 best to reboot so that all daemons are in a known state, to reduce the
 potential for confusion later (such as finding that when you send mail
 to a jail, and its sendmail is down, the mail is delivered to the host,
 etc.).
 .Ss "Configuring the Jail"
 Start any jail for the first time without configuring the network
 interface so that you can clean it up a little and set up accounts.
 As
 with any machine (virtual or not), you will need to set a root password, time
 zone, etc.
 Some of these steps apply only if you intend to run a full virtual server
 inside the jail; others apply both for constraining a particular application
 or for running a virtual server.
 .Pp
 Start a shell in the jail:
 .Bd -literal -offset indent
 jail -c path=/data/jail/testjail mount.devfs \\
 	host.hostname=testhostname ip4.addr=192.0.2.100 \\
 	command=/bin/sh
 .Ed
 .Pp
 Assuming no errors, you will end up with a shell prompt within the jail.
 You can now run
 .Xr bsdconfig 8
 and do the post-install configuration to set various configuration options,
 or perform these actions manually by editing
 .Pa /etc/rc.conf ,
 etc.
 .Pp
 .Bl -bullet -offset indent -compact
 .It
 Configure
 .Pa /etc/resolv.conf
 so that name resolution within the jail will work correctly.
 .It
 Run
 .Xr newaliases 1
 to quell
 .Xr sendmail 8
 warnings.
 .It
 Set a root password, probably different from the real host system.
 .It
 Set the timezone.
 .It
 Add accounts for users in the jail environment.
 .It
 Install any packages the environment requires.
 .El
 .Pp
 You may also want to perform any package-specific configuration (web servers,
 SSH servers, etc), patch up
 .Pa /etc/syslog.conf
 so it logs as you would like, etc.
 If you are not using a virtual server, you may wish to modify
 .Xr syslogd 8
 in the host environment to listen on the syslog socket in the jail
 environment; in this example, the syslog socket would be stored in
 .Pa /data/jail/testjail/var/run/log .
 .Pp
 Exit from the shell, and the jail will be shut down.
 .Ss "Starting the Jail"
 You are now ready to restart the jail and bring up the environment with
 all of its daemons and other programs.
 Create an entry for the jail in
 .Pa /etc/jail.conf :
 .Bd -literal -offset indent
 testjail {
 	path = /tmp/jail/testjail;
 	mount.devfs;
 	host.hostname = testhostname;
 	ip4.addr = 192.0.2.100;
 	interface = em0;
 	exec.start = "/bin/sh /etc/rc";
 	exec.stop = "/bin/sh /etc/rc.shutdown jail";
 }
 .Ed
 .Pp
 To start a virtual server environment,
 .Pa /etc/rc
 is run to launch various daemons and services, and
 .Pa /etc/rc.shutdown
 is run to shut them down when the jail is removed.
 If you are running a single application in the jail,
 substitute the command used to start the application for
 .Dq /bin/sh /etc/rc ;
 there may be some script available to cleanly shut down the application,
 or it may be sufficient to go without a stop command, and have
 .Nm
 send
 .Dv SIGTERM
 to the application.
 .Pp
 Start the jail by running:
 .Bd -literal -offset indent
 jail -c testjail
 .Ed
 .Pp
 A few warnings may be produced; however, it should all work properly.
 You should be able to see
 .Xr inetd 8 ,
 .Xr syslogd 8 ,
 and other processes running within the jail using
 .Xr ps 1 ,
 with the
 .Ql J
 flag appearing beside jailed processes.
 To see an active list of jails, use
 .Xr jls 8 .
 If
 .Xr sshd 8
 is enabled in the jail environment, you should be able to
 .Xr ssh 1
 to the hostname or IP address of the jailed environment, and log
 in using the accounts you created previously.
 .Pp
 It is possible to have jails started at boot time.
 Please refer to the
 .Dq jail_*
 variables in
 .Xr rc.conf 5
 for more information.
 .Ss "Managing the Jail"
 Normal machine shutdown commands, such as
 .Xr halt 8 ,
 .Xr reboot 8 ,
 and
 .Xr shutdown 8 ,
 cannot be used successfully within the jail.
 To kill all processes from within a jail, you may use one of the
 following commands, depending on what you want to accomplish:
 .Bd -literal -offset indent
 kill -TERM -1
 kill -KILL -1
 .Ed
 .Pp
 This will send the
 .Dv SIGTERM
 or
 .Dv SIGKILL
 signals to all processes in the jail \(em be careful not to run this from
 the host environment!
 Once all of the jail's processes have died, unless the jail was created
 with the
 .Va persist
 parameter, the jail will be removed.
 Depending on
 the intended use of the jail, you may also want to run
 .Pa /etc/rc.shutdown
 from within the jail.
 .Pp
 To shut down the jail from the outside, simply remove it with:
 .Bd -literal -offset indent
 jail -r
 .Ed
 .Pp
 which will run any commands specified by
 .Va exec.stop ,
 and then send
 .Dv SIGTERM
 and eventually
 .Dv SIGKILL
 to any remaining jailed processes.
 .Pp
 The
 .Pa /proc/ Ns Ar pid Ns Pa /status
 file contains, as its last field, the name of the jail in which the
 process runs, or
 .Dq Li -
 to indicate that the process is not running within a jail.
 The
 .Xr ps 1
 command also shows a
 .Ql J
 flag for processes in a jail.
 .Pp
 You can also list/kill processes based on their jail ID.
 To show processes and their jail ID, use the following command:
 .Pp
 .Dl "ps ax -o pid,jid,args"
 .Pp
 To show and then kill processes in jail number 3 use the following commands:
 .Bd -literal -offset indent
 pgrep -lfj 3
 pkill -j 3
 .Ed
 or:
 .Pp
 .Dl "killall -j 3"
 .Ss "Jails and File Systems"
 It is not possible to
 .Xr mount 8
 or
 .Xr umount 8
 any file system inside a jail unless the file system is marked
 jail-friendly, the jail's
 .Va allow.mount
 parameter is set, and the jail's
 .Va enforce_statfs
 parameter is lower than 2.
 .Pp
 Multiple jails sharing the same file system can influence each other.
 For example, a user in one jail can fill the file system,
 leaving no space for processes in the other jail.
 Trying to use
 .Xr quota 1
 to prevent this will not work either, as the file system quotas
 are not aware of jails but only look at the user and group IDs.
 This means the same user ID in two jails share a single file
 system quota.
 One would need to use one file system per jail to make this work.
 .Ss "Sysctl MIB Entries"
 The read-only entry
 .Va security.jail.jailed
 can be used to determine if a process is running inside a jail (value
 is one) or not (value is zero).
 .Pp
 The variable
 .Va security.jail.jail_max_af_ips
 determines how may address per address family a jail may have.
 The default is 255.
 .Pp
 Some MIB variables have per-jail settings.
 Changes to these variables by a jailed process do not affect the host
 environment, only the jail environment.
 These variables are
 .Va kern.securelevel ,
 .Va security.bsd.suser_enabled ,
 .Va kern.hostname ,
 .Va kern.domainname ,
 .Va kern.hostid ,
 and
 .Va kern.hostuuid .
 .Ss "Hierarchical Jails"
 By setting a jail's
 .Va children.max
 parameter, processes within a jail may be able to create jails of their own.
 These child jails are kept in a hierarchy, with jails only able to see and/or
 modify the jails they created (or those jails' children).
 Each jail has a read-only
 .Va parent
 parameter, containing the
 .Va jid
 of the jail that created it; a
 .Va jid
 of 0 indicates the jail is a child of the current jail (or is a top-level
 jail if the current process isn't jailed).
 .Pp
 Jailed processes are not allowed to confer greater permissions than they
 themselves are given, e.g., if a jail is created with
 .Va allow.nomount ,
 it is not able to create a jail with
 .Va allow.mount
 set.
 Similarly, such restrictions as
 .Va ip4.addr
 and
 .Va securelevel
 may not be bypassed in child jails.
 .Pp
 A child jail may in turn create its own child jails if its own
 .Va children.max
 parameter is set (remember it is zero by default).
 These jails are visible to and can be modified by their parent and all
 ancestors.
 .Pp
 Jail names reflect this hierarchy, with a full name being an MIB-type string
 separated by dots.
 For example, if a base system process creates a jail
 .Dq foo ,
 and a process under that jail creates another jail
 .Dq bar ,
 then the second jail will be seen as
 .Dq foo.bar
 in the base system (though it is only seen as
 .Dq bar
 to any processes inside jail
 .Dq foo ) .
 Jids on the other hand exist in a single space, and each jail must have a
 unique jid.
 .Pp
 Like the names, a child jail's
 .Va path
 appears relative to its creator's own
 .Va path .
 This is by virtue of the child jail being created in the chrooted
 environment of the first jail.
 .Sh SEE ALSO
 .Xr killall 1 ,
 .Xr lsvfs 1 ,
 .Xr newaliases 1 ,
 .Xr pgrep 1 ,
 .Xr pkill 1 ,
 .Xr ps 1 ,
 .Xr quota 1 ,
 .Xr jail_set 2 ,
 .Xr vmm 4 ,
 .Xr devfs 5 ,
 .Xr fdescfs 5 ,
 .Xr jail.conf 5 ,
 .Xr linprocfs 5 ,
 .Xr linsysfs 5 ,
 .Xr procfs 5 ,
 .Xr rc.conf 5 ,
 .Xr sysctl.conf 5 ,
 .Xr bsdconfig 8 ,
 .Xr chroot 8 ,
 .Xr devfs 8 ,
 .Xr halt 8 ,
 .Xr ifconfig 8 ,
 .Xr inetd 8 ,
 .Xr jexec 8 ,
 .Xr jls 8 ,
 .Xr mount 8 ,
 .Xr mountd 8 ,
 .Xr nfsd 8 ,
 .Xr reboot 8 ,
 .Xr rpcbind 8 ,
 .Xr sendmail 8 ,
 .Xr shutdown 8 ,
 .Xr sysctl 8 ,
 .Xr syslogd 8 ,
 .Xr umount 8
 .Sh HISTORY
 The
 .Nm
 utility appeared in
 .Fx 4.0 .
 Hierarchical/extensible jails were introduced in
 .Fx 8.0 .
 The configuration file was introduced in
 .Fx 9.1 .
 .Sh AUTHORS
 .An -nosplit
 The jail feature was written by
 .An Poul-Henning Kamp
 for R&D Associates
 who contributed it to
 .Fx .
 .Pp
 .An Robert Watson
 wrote the extended documentation, found a few bugs, added
 a few new features, and cleaned up the userland jail environment.
 .Pp
 .An Bjoern A. Zeeb
 added multi-IP jail support for IPv4 and IPv6 based on a patch
 originally done by
 .An Pawel Jakub Dawidek
 for IPv4.
 .Pp
 .An James Gritton
 added the extensible jail parameters, hierarchical jails,
 and the configuration file.
 .Sh BUGS
 It might be a good idea to add an
 address alias flag such that daemons listening on all IPs
 .Pq Dv INADDR_ANY
 will not bind on that address, which would facilitate building a safe
 host environment such that host daemons do not impose on services offered
 from within jails.
 Currently, the simplest answer is to minimize services
 offered on the host, possibly limiting it to services offered from
 .Xr inetd 8
 which is easily configurable.
 .Sh NOTES
 Great care should be taken when managing directories visible within the jail.
 For example, if a jailed process has its current working directory set to a
 directory that is moved out of the jail's chroot, then the process may gain
 access to the file space outside of the jail.
 It is recommended that directories always be copied, rather than moved, out
 of a jail.
 .Pp
 In addition, there are several ways in which an unprivileged user
 outside the jail can cooperate with a privileged user inside the jail
 and thereby obtain elevated privileges in the host environment.
 Most of these attacks can be mitigated by ensuring that the jail root
 is not accessible to unprivileged users in the host environment.
 Regardless, as a general rule, untrusted users with privileged access
 to a jail should not be given access to the host environment.