Add support for the arbitrary named jail parameters used by jail_set(2)

and jail_get(2).  Jail(8) can now create jails using a "name=value"
format instead of just specifying a limited set of fixed parameters; it
can also modify parameters of existing jails.  Jls(8) can display all
parameters of jails, or a specified set of parameters.  The available
parameters are gathered from the kernel, and not hard-coded into these
programs.

Small patches on killall(1) and jexec(8) to support jail names with
jail_get(2).

Approved by:	bz (mentor)

8 files changed, 1586 insertions, 820 deletions

diff --git a/usr.sbin/jail/jail.8 b/usr.sbin/jail/jail.8
index 3a0767e..ee6ea0e 100644
--- a/usr.sbin/jail/jail.8
+++ b/usr.sbin/jail/jail.8
@@ -1,5 +1,6 @@
 .\"
 .\" Copyright (c) 2000, 2003 Robert N. M. Watson
+.\" Copyright (c) 2008 James Gritton
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -33,49 +34,67 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 24, 2009
+.Dd May 27, 2009
 .Dt JAIL 8
 .Os
 .Sh NAME
 .Nm jail
-.Nd "imprison process and its descendants"
+.Nd "create or modify a system jail"
 .Sh SYNOPSIS
 .Nm
+.Op Fl dhi
+.Op Fl J Ar jid_file
+.Op Fl l u Ar username | Fl U Ar username
+.Op Fl c | m
+.Op Ar parameter=value ...
+.Br
+.Nm
 .Op Fl hi
 .Op Fl n Ar jailname
 .Op Fl J Ar jid_file
 .Op Fl s Ar securelevel
 .Op Fl l u Ar username | Fl U Ar username
-.Ar path hostname [ip[,..]] command ...
+.Op Ar path hostname [ip[,..]] command ...
+.Br
+.Nm
+.Op Fl r Ar jail
 .Sh DESCRIPTION
 The
 .Nm
-utility imprisons a process and all future descendants.
+utility creates a new jail or modifies an existing jail, optionally
+imprisoning the current process (and future descendants) inside it.
 .Pp
 The options are as follows:
-.Bl -tag -width ".Fl u Ar username"
+.Bl -tag -width indent
+.It Fl d
+Allow making changes to a
+.Va
+dying jail.
 .It Fl h
-Resolve
-.Va hostname
+Resolve the
+.Va host.hostname
+parameter (or
+.Va hostname )
 and add all IP addresses returned by the resolver
 to the list of
-.Va ip-addresses
-for this prison.
+.Va ip
+addresses for this prison.
 This may affect default address selection for outgoing IPv4 connections
 of prisons.
 The address first returned by the resolver for each address family
 will be used as primary address.
-See
-.Va ip-addresses
-further down for details.
+See the
+.Va ip4.addr
+and
+.Va ip6.addr
+parameters further down for details.
 .It Fl i
 Output the jail identifier of the newly created jail.
 .It Fl n Ar jailname
-Assign and administrative name to the jail that can be used for management
-or auditing purposes.
-The system will
-.Sy not enforce
-the name to be unique.
+Set the jail's name.
+This is deprecated and is equivalent to setting the
+.Va name
+parameter.
 .It Fl J Ar jid_file
 Write a
 .Ar jid_file
@@ -98,9 +117,12 @@ is imported from the current environment.
 The environment variables from the login class capability database for the
 target login are also set.
 .It Fl s Ar securelevel
-Sets the
+Set the
 .Va kern.securelevel
-sysctl variable to the specified value inside the newly created jail.
+MIB entry to the specified value inside the newly created jail.
+This is deprecated and is equivalent to setting the
+.Va securelevel
+parameter.
 .It Fl u Ar username
 The user name from host environment as whom the
 .Ar command
@@ -109,20 +131,241 @@ should run.
 The user name from jailed environment as whom the
 .Ar command
 should run.
-.It Ar path
+.It Fl c
+Create a new jail.
+The
+.Va jid
+and
+.Va name
+parameters (if specified) must not refer to an existing jail.
+.It Fl m
+Modify an existing jail.
+One of the
+.Va jid
+or
+.Va name
+parameters must exist and refer to an existing jail.
+.It Fl cm
+Create a jail if it does not exist, or modify a jail if it does exist.
+.It Fl r
+Remove the
+.Ar jail
+specified by jid or name.
+All jailed processes are killed, and all children of this jail are also
+removed.
+.El
+.Pp
+At least one of the
+.Fl c ,
+.Fl m
+or
+.Fl r
+options must be specified.
+.Pp
+.Ar Parameters
+are listed in
+.Dq name=value
+form, following the options.
+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 .
+Any parameters not set will be given default values, often based on the
+current environment.
+.Pp
+The pseudo-parameter
+.Va command
+specifies that the current process should enter the new (or modified) jail,
+and run the specified command.
+It must be the last parameter specified, because it includes not only
+the value following the
+.Sq =
+sign, but also passes the rest of the arguments to the command.
+.Pp
+Instead of supplying named
+.Ar parameters ,
+four fixed parameters may be supplied in order on the command line:
+.Ar path ,
+.Ar hostname ,
+.Ar ip ,
+and
+.Ar command .
+As the
+.Va jid
+and
+.Va name
+parameters aren't in this list, this mode will always create a new jail, and
+the
+.Fl c
+and
+.Fl o
+options don't apply (and must not exist).
+.Pp
+Jails have a set a core parameters, and 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 .
+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 .
+.It Va path
 Directory which is to be the root of the prison.
-.It Ar hostname
-Hostname of the prison.
-.It Ar ip-addresses
-None, one or more IPv4 and IPv6 addresses assigned to the prison.
-The first address of each address family that was assigned to the jail will
-be used as the source address in case source address selection on unbound
-sockets cannot find a better match.
+The
+.Va command
+(if any) is run from this directory, as are commands from
+.Xr jexec 8 .
+.It Va ip4.addr
+A comma-separated list of IPv4 addresses assigned to the prison.
+If this is set, the jail is restricted to using only these address.
+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 kept used as the source address
+in case 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 for the address family in question.
-.It Ar command
-Pathname of the program which is to be executed.
+assigned to itself.
+.Pp
+A list of zero elements (an empty string) will stop the jail from using IPv4
+entirely; setting the boolean parameter
+.Ar noip4
+will not restrict the jail at all.
+.It Va ip6.addr
+A list of IPv6 addresses assigned to the prison, the counterpart to
+.Ar ip4.addr
+above.
+.It Va host.hostname
+Hostname of the prison.
+If not specified, a jail will use the system hostname.
+.It Va securelevel
+The value of the jail's
+.Va kern.securelevel
+sysctl.
+A jail never has a lower securelevel than the default 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 enforce_statfs
+This determines which 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 jail is destroyed as its last process exits.
+A new jail must have either the
+.Va persist
+parameter or
+.Va command
+pseudo-parameter set.
+.It Va cpuset
+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 allow.*
+Some restrictions of the jail environment may be set on a per-jail
+basis.
+With the exception of
+.Va allow.set_hostname ,
+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.
+In the current jail implementation, System V primitives share a single
+namespace across the host and jail environments, meaning that processes
+within a jail would be able to communicate with (and potentially interfere
+with) processes outside of the jail, and in other jails.
+.It Va allow.raw_sockets
+The prison root is allowed to create raw sockets.
+Setting this parameter allows utilities like
+.Xr ping 8
+and
+.Xr traceroute 8
+to operate inside the prison.
+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, priveleged 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.
+.It Va allow.quotas
+The prison 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.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.jails
+The prison root may create child jails under this jail.  See the
+.Va "Hierarchical Jails"
+section for more information.
+.El
 .El
 .Pp
 Jails are typically set up using one of two philosophies: either to
@@ -142,10 +385,6 @@ process.
 This manual page documents the configuration steps necessary to support
 either of these steps, although the configuration steps may be
 refined based on local requirements.
-.Pp
-Please see the
-.Xr jail 2
-man page for further details.
 .Sh EXAMPLES
 .Ss "Setting up a Jail Directory Tree"
 To set up a jail directory tree containing an entire
@@ -289,7 +528,10 @@ or for running a virtual server.
 .Pp
 Start a shell in the jail:
 .Pp
-.Dl "jail /data/jail/192.0.2.100 testhostname 192.0.2.100 /bin/sh"
+.Bd -literal -offset indent
+jail path=/data/jail/192.0.2.100 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
@@ -359,20 +601,11 @@ To do this, first bring up the
 virtual host interface, and then start the jail's
 .Pa /etc/rc
 script from within the jail.
-.Pp
-NOTE: If you plan to allow untrusted users to have root access inside the
-jail, you may wish to consider setting the
-.Va security.jail.set_hostname_allowed
-sysctl variable to 0.
-Please see the management discussion later in this document as to why this
-may be a good idea.
-If you do decide to set this variable,
-it must be set before starting any jails, and once each boot.
 .Bd -literal -offset indent
 ifconfig ed0 inet alias 192.0.2.100/32
 mount -t procfs proc /data/jail/192.0.2.100/proc
-jail /data/jail/192.0.2.100 testhostname 192.0.2.100 \\
-	/bin/sh /etc/rc
+jail path=/data/jail/192.0.2.100 host.hostname=testhostname \\
+	ip4=addr.192.0.2.100 command=/bin/sh /etc/rc
 .Ed
 .Pp
 A few warnings will be produced, because most
@@ -442,10 +675,15 @@ To kill processes from outside the jail, use the
 utility in conjunction with the one of the
 .Xr kill 1
 commands above.
+You may also remove the jail with
+.Nm
+.Ar -r ,
+which will killall the jail's processes with
+.Dv SIGKILL .
 .Pp
 The
 .Pa /proc/ Ns Ar pid Ns Pa /status
-file contains, as its last field, the hostname of the jail in which the
+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.
@@ -454,20 +692,6 @@ The
 command also shows a
 .Ql J
 flag for processes in a jail.
-However, the hostname for a jail may be, by
-default, modified from within the jail, so the
-.Pa /proc
-status entry is unreliable by default.
-To disable the setting of the hostname
-from within a jail, set the
-.Va security.jail.set_hostname_allowed
-sysctl variable in the host environment to 0, which will affect all jails.
-You can have this sysctl set on each boot using
-.Xr sysctl.conf 5 .
-Just add the following line to
-.Pa /etc/sysctl.conf :
-.Pp
-.Dl security.jail.set_hostname_allowed=0
 .Pp
 You can also list/kill processes based on their jail ID.
 To show processes and their jail ID, use the following command:
@@ -488,12 +712,9 @@ It is not possible to
 or
 .Xr umount 8
 any file system inside a jail unless the file system is marked
-jail-friendly.
-See
-.Va security.jail.mount_allowed
-in the
-.Va "Sysctl MIB Entries"
-section.
+jail-friendly and the jail's
+.Va allow.mount
+parameter is set.
 .Pp
 Multiple jails sharing the same file system can influence each other.
 For example a user in one jail can fill the file system also
@@ -506,132 +727,77 @@ This means the same user ID in two jails share the same file
 system quota.
 One would need to use one file system per jail to make this working.
 .Ss "Sysctl MIB Entries"
-Certain aspects of the jail containments environment may be modified from
-the host environment using
-.Xr sysctl 8
-MIB variables.
-Currently, these variables affect all jails on the system, although in
-the future this functionality may be finer grained.
-.Bl -tag -width XXX
-.It Va security.jail.allow_raw_sockets
-This MIB entry determines whether or not prison root is allowed to
-create raw sockets.
-Setting this MIB to 1 allows utilities like
-.Xr ping 8
-and
-.Xr traceroute 8
-to operate inside the prison.
-If this MIB
-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.
-As such,
-by default this option is disabled.
-.It Va security.jail.enforce_statfs
-This MIB entry determines which 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 security.jail.set_hostname_allowed
-This MIB entry determines whether or not processes within a jail are
-allowed to change their hostname via
-.Xr hostname 1
-or
-.Xr sethostname 3 .
-In the current jail implementation, the ability to set the hostname from
-within the jail can impact management tools relying on the accuracy of jail
-information in
-.Pa /proc .
-As such, this should be disabled in environments where privileged access to
-jails is given out to untrusted parties.
-.It Va security.jail.socket_unixiproute_only
-The jail functionality binds an IPv4 address to each jail, and limits
-access to other network addresses in the IPv4 space that may be available
-in the host environment.
-However, jail is not currently able to limit access to other network
-protocol stacks that have not had jail functionality added to them.
-As such, by default, processes within jails may only access protocols
-in the following domains:
-.Dv PF_LOCAL , PF_INET ,
-and
-.Dv PF_ROUTE ,
-permitting them access to
-.Ux
-domain sockets,
-IPv4 addresses, and routing sockets.
-To enable access to other domains, this MIB variable may be set to
-0.
-.It Va security.jail.sysvipc_allowed
-This MIB entry determines whether or not processes within a jail have access
-to System V IPC primitives.
-In the current jail implementation, System V primitives share a single
-namespace across the host and jail environments, meaning that processes
-within a jail would be able to communicate with (and potentially interfere
-with) processes outside of the jail, and in other jails.
-As such, this functionality is disabled by default, but can be enabled
-by setting this MIB entry to 1.
-.It Va security.jail.chflags_allowed
-This MIB entry determines how a privileged user inside a jail will be
-treated by
-.Xr chflags 2 .
-If zero, such users are treated as unprivileged, and are unable to set
-or clear system file flags; if non-zero, such users are treated as
-privileged, and may manipulate system file flags subject to the usual
-constraints on
-.Va kern.securelevel .
-.It Va security.jail.mount_allowed
-This MIB entry determines if a privileged user inside a 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 functionality is disabled by default, but can be enabled by setting this
-MIB entry to 1.
-.It Va security.jail.jail_max_af_ips
-This MIB entry determines how may address per address family a prison
-may have. The default is 255.
-.El
-.Pp
-The read-only sysctl variable
+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
-.Va security.jail.list
-MIB entry is read-only and it returns an array of
-.Vt "struct xprison"
-defined in
-.In sys/jail.h .
-It is recommended to use the
-.Xr jls 8
-utility to see current active list of jails.
+The variable
+.Va security.jail.max_af_ips
+determines how may address per address family a prison may have.
+The default is 255.
 .Pp
-There are currently two MIB related variables that have per-jail settings.
+There are currently two MIB variables that have per-jail settings.
 Changes to these variables by a jailed process do not effect the host
 environment, only the jail environment.
 The variables are
 .Va kern.securelevel
 and
 .Va kern.hostname .
+.Ss "Hierarchical Jails"
+By setting a jail's
+.Va allow.jails
+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 allow.jails
+parameter is set (remember it is off 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
+is 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 ,
@@ -641,7 +807,7 @@ and
 .Xr ps 1 ,
 .Xr quota 1 ,
 .Xr chroot 2 ,
-.Xr jail 2 ,
+.Xr jail_set 2 ,
 .Xr jail_attach 2 ,
 .Xr procfs 5 ,
 .Xr rc.conf 5 ,
@@ -665,6 +831,8 @@ The
 .Nm
 utility appeared in
 .Fx 4.0 .
+Hierarchical/extensible jails were introduced in
+.Fx 8.0 .
 .Sh AUTHORS
 .An -nosplit
 The jail feature was written by
@@ -683,6 +851,9 @@ 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 and hierchical jails.
 .Sh BUGS
 Jail currently lacks the ability to allow access to
 specific jail information via
diff --git a/usr.sbin/jail/jail.c b/usr.sbin/jail/jail.c
index 518ded0..672c306 100644
--- a/usr.sbin/jail/jail.c
+++ b/usr.sbin/jail/jail.c
@@ -1,5 +1,6 @@
 /*-
  * Copyright (c) 1999 Poul-Henning Kamp.
+ * Copyright (c) 2009 James Gritton
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -29,50 +30,53 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/jail.h>
-#include <sys/queue.h>
 #include <sys/socket.h>
 #include <sys/sysctl.h>
-#include <sys/types.h>
+#include <sys/uio.h>
 
-#include <netinet/in.h>
 #include <arpa/inet.h>
-#include <netdb.h>
+#include <netinet/in.h>
 
+#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <grp.h>
 #include <login_cap.h>
+#include <netdb.h>
 #include <paths.h>
 #include <pwd.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <strings.h>
 #include <string.h>
 #include <unistd.h>
 
-static void		usage(void);
-static int		add_addresses(struct addrinfo *);
-static struct in_addr	*copy_addr4(void);
+#define	SJPARAM		"security.jail.param"
+#define	ERRMSG_SIZE	256
+
+struct param {
+	struct iovec name;
+	struct iovec value;
+};
+
+static struct param *params;
+static char **param_values;
+static int nparams;
+
+static char *ip4_addr;
 #ifdef INET6
-static struct in6_addr	*copy_addr6(void);
+static char *ip6_addr;
 #endif
 
-extern char	**environ;
-
-struct addr4entry {
-	STAILQ_ENTRY(addr4entry)	addr4entries;
-	struct in_addr			ip4;
-	int				count;
-};
-struct addr6entry {
-	STAILQ_ENTRY(addr6entry)	addr6entries;
+static void add_ip_addr(char **addrp, char *newaddr);
 #ifdef INET6
-	struct in6_addr			ip6;
+static void add_ip_addr46(char *newaddr);
 #endif
-	int				count;
-};
-STAILQ_HEAD(addr4head, addr4entry) addr4 = STAILQ_HEAD_INITIALIZER(addr4);
-STAILQ_HEAD(addr6head, addr6entry) addr6 = STAILQ_HEAD_INITIALIZER(addr6);
+static void add_ip_addrinfo(int ai_flags, char *value);
+static void quoted_print(FILE *fp, char *str);
+static void set_param(const char *name, char *value);
+static void usage(void);
+
+extern char **environ;
 
 #define GET_USER_INFO do {						\
 	pwd = getpwnam(username);					\
@@ -94,25 +98,28 @@ int
 main(int argc, char **argv)
 {
 	login_cap_t *lcap = NULL;
-	struct jail j;
+	struct iovec rparams[2];
 	struct passwd *pwd = NULL;
 	gid_t groups[NGROUPS];
-	int ch, error, i, ngroups, securelevel;
-	int hflag, iflag, Jflag, lflag, uflag, Uflag;
-	char path[PATH_MAX], *jailname, *ep, *username, *JidFile, *ip;
+	int ch, cmdarg, i, jail_set_flags, jid, ngroups;
+	int hflag, iflag, Jflag, lflag, rflag, uflag, Uflag;
+	char *ep, *jailname, *securelevel, *username, *JidFile;
+	char errmsg[ERRMSG_SIZE];
 	static char *cleanenv;
 	const char *shell, *p = NULL;
-	long ltmp;
 	FILE *fp;
-	struct addrinfo hints, *res0;
 
-	hflag = iflag = Jflag = lflag = uflag = Uflag = 0;
-	securelevel = -1;
-	jailname = username = JidFile = cleanenv = NULL;
+	hflag = iflag = Jflag = lflag = rflag = uflag = Uflag =
+	    jail_set_flags = 0;
+	cmdarg = jid = -1;
+	jailname = securelevel = username = JidFile = cleanenv = NULL;
 	fp = NULL;
 
-	while ((ch = getopt(argc, argv, "hiln:s:u:U:J:")) != -1) {
+	while ((ch = getopt(argc, argv, "cdhilmn:r:s:u:U:J:")) != -1) {
 		switch (ch) {
+		case 'd':
+			jail_set_flags |= JAIL_DYING;
+			break;
 		case 'h':
 			hflag = 1;
 			break;
@@ -127,10 +134,7 @@ main(int argc, char **argv)
 			jailname = optarg;
 			break;
 		case 's':
-			ltmp = strtol(optarg, &ep, 0);
-			if (*ep || ep == optarg || ltmp > INT_MAX || !ltmp)
-				errx(1, "invalid securelevel: `%s'", optarg);
-			securelevel = ltmp;
+			securelevel = optarg;
 			break;
 		case 'u':
 			username = optarg;
@@ -143,13 +147,39 @@ main(int argc, char **argv)
 		case 'l':
 			lflag = 1;
 			break;
+		case 'c':
+			jail_set_flags |= JAIL_CREATE;
+			break;
+		case 'm':
+			jail_set_flags |= JAIL_UPDATE;
+			break;
+		case 'r':
+			jid = strtoul(optarg, &ep, 10);
+			if (!*optarg || *ep) {
+				*(const void **)&rparams[0].iov_base = "name";
+				rparams[0].iov_len = sizeof("name");
+				rparams[1].iov_base = optarg;
+				rparams[1].iov_len = strlen(optarg) + 1;
+				jid = jail_get(rparams, 2, 0);
+				if (jid < 0)
+					errx(1, "unknown jail: %s", optarg);
+			}
+			rflag = 1;
+			break;
 		default:
 			usage();
 		}
 	}
 	argc -= optind;
 	argv += optind;
-	if (argc < 4)
+	if (rflag) {
+		if (argc > 0 || iflag || Jflag || lflag || uflag || Uflag)
+			usage();
+		if (jail_remove(jid) < 0)
+			err(1, "jail_remove");
+		exit (0);
+	}
+	if (argc == 0)
 		usage();
 	if (uflag && Uflag)
 		usage();
@@ -157,92 +187,118 @@ main(int argc, char **argv)
 		usage();
 	if (uflag)
 		GET_USER_INFO;
-	if (realpath(argv[0], path) == NULL)
-		err(1, "realpath: %s", argv[0]);
-	if (chdir(path) != 0)
-		err(1, "chdir: %s", path);
-	/* Initialize struct jail. */
-	memset(&j, 0, sizeof(j));
-	j.version = JAIL_API_VERSION;
-	j.path = path;
-	j.hostname = argv[1];
-	if (jailname != NULL)
-		j.jailname = jailname;
-
-	/* Handle IP addresses. If requested resolve hostname too. */
-	bzero(&hints, sizeof(struct addrinfo));
-	hints.ai_protocol = IPPROTO_TCP;
-	hints.ai_socktype = SOCK_STREAM;
-	if (JAIL_API_VERSION < 2)
-		hints.ai_family = PF_INET;
-	else
-		hints.ai_family = PF_UNSPEC;
-	/* Handle hostname. */
-	if (hflag != 0) {
-		error = getaddrinfo(j.hostname, NULL, &hints, &res0);
-		if (error != 0)
-			errx(1, "failed to handle hostname: %s",
-			    gai_strerror(error));
-		error = add_addresses(res0);
-		freeaddrinfo(res0);
-		if (error != 0)
-			errx(1, "failed to add addresses.");
-	}
-	/* Handle IP addresses. */
-	hints.ai_flags = AI_NUMERICHOST;
-	ip = strtok(argv[2], ",");
-	while (ip != NULL) {
-		error = getaddrinfo(ip, NULL, &hints, &res0);
-		if (error != 0)
-			errx(1, "failed to handle ip: %s", gai_strerror(error));
-		error = add_addresses(res0);
-		freeaddrinfo(res0);
-		if (error != 0)
-			errx(1, "failed to add addresses.");
-		ip = strtok(NULL, ",");
-	}
-	/* Count IP addresses and add them to struct jail. */
-	if (!STAILQ_EMPTY(&addr4)) {
-		j.ip4s = STAILQ_FIRST(&addr4)->count;
-		j.ip4 = copy_addr4();
-		if (j.ip4s > 0 && j.ip4 == NULL)
-			errx(1, "copy_addr4()");
-	}
+
+	/*
+	 * If the first argument (path) starts with a slash, and the third
+	 * argument (IP address) starts with a digit, it is likely to be
+	 * an old-style fixed-parameter command line.
+	 */
+	if (jailname)
+		set_param("name", jailname);
+	if (securelevel)
+		set_param("securelevel", securelevel);
+	if (jail_set_flags) {
+		for (i = 0; i < argc; i++) {
+			if (!strncmp(argv[i], "command=", 8)) {
+				cmdarg = i;
+				argv[cmdarg] += 8;
+				jail_set_flags |= JAIL_ATTACH;
+				break;
+			}
+			if (hflag) {
+				if (!strncmp(argv[i], "ip4.addr=", 9)) {
+					add_ip_addr(&ip4_addr, argv[i] + 9);
+					break;
+				}
 #ifdef INET6
-	if (!STAILQ_EMPTY(&addr6)) {
-		j.ip6s = STAILQ_FIRST(&addr6)->count;
-		j.ip6 = copy_addr6();
-		if (j.ip6s > 0 && j.ip6 == NULL)
-			errx(1, "copy_addr6()");
+				if (!strncmp(argv[i], "ip6.addr=", 9)) {
+					add_ip_addr(&ip6_addr, argv[i] + 9);
+					break;
+				}
+#endif
+				if (!strncmp(argv[i], "host.hostname=", 14))
+					add_ip_addrinfo(0, argv[i] + 14);
+			}
+			set_param(NULL, argv[i]);
+		}
+	} else {
+		if (argc < 4 || argv[0][0] != '/')
+			errx(1, "%s\n%s",
+			   "no -c or -m, so this must be an old-style command.",
+			   "But it doesn't look like one.");
+		set_param("path", argv[0]);
+		set_param("host.hostname", argv[1]);
+		if (hflag)
+			add_ip_addrinfo(0, argv[1]);
+#ifdef INET6
+		add_ip_addr46(argv[2]);
+#else
+		add_ip_addr(&ip4_addr, argv[2]);
+#endif
+		cmdarg = 3;
 	}
-#endif 
+	if (ip4_addr != NULL)
+		set_param("ip4.addr", ip4_addr);
+#ifdef INET6
+	if (ip6_addr != NULL)
+		set_param("ip6.addr", ip6_addr);
+#endif
+	errmsg[0] = 0;
+	set_param("errmsg", errmsg);
 
 	if (Jflag) {
 		fp = fopen(JidFile, "w");
 		if (fp == NULL)
 			errx(1, "Could not create JidFile: %s", JidFile);
 	}
-	i = jail(&j);
-	if (i == -1)
-		err(1, "syscall failed with");
+	jid = jail_set(&params->name, 2 * nparams,
+	    jail_set_flags ? jail_set_flags : JAIL_CREATE | JAIL_ATTACH);
+	if (jid < 0) {
+		if (errmsg[0] != '\0')
+			errx(1, "%s", errmsg);
+		err(1, "jail_set");
+	}
 	if (iflag) {
-		printf("%d\n", i);
+		printf("%d\n", jid);
 		fflush(stdout);
 	}
 	if (Jflag) {
-		if (fp != NULL) {
-			fprintf(fp, "%d\t%s\t%s\t%s\t%s\n",
-			    i, j.path, j.hostname, argv[2], argv[3]);
-			(void)fclose(fp);
+		if (jail_set_flags) {
+			fprintf(fp, "jid=%d", jid);
+			for (i = 0; i < nparams; i++)
+				if (strcmp(params[i].name.iov_base, "jid") &&
+				    strcmp(params[i].name.iov_base, "errmsg")) {
+					fprintf(fp, " %s",
+					    (char *)params[i].name.iov_base);
+					if (param_values[i]) {
+						putc('=', fp);
+						quoted_print(fp,
+						    param_values[i]);
+					}
+				}
+			fprintf(fp, "\n");
 		} else {
-			errx(1, "Could not write JidFile: %s", JidFile);
+			for (i = 0; i < nparams; i++)
+				if (!strcmp(params[i].name.iov_base, "path"))
+					break;
+#ifdef INET6
+			fprintf(fp, "%d\t%s\t%s\t%s%s%s\t%s\n",
+			    jid, i < nparams
+			    ? (char *)params[i].value.iov_base : argv[0],
+			    argv[1], ip4_addr ? ip4_addr : "",
+			    ip4_addr && ip4_addr[0] && ip6_addr && ip6_addr[0]
+			    ? "," : "", ip6_addr ? ip6_addr : "", argv[3]);
+#else
+			fprintf(fp, "%d\t%s\t%s\t%s\t%s\n",
+			    jid, i < nparams
+			    ? (char *)params[i].value.iov_base : argv[0],
+			    argv[1], ip4_addr ? ip4_addr : "", argv[3]);
+#endif
 		}
+		(void)fclose(fp);
 	}
-	if (securelevel > 0) {
-		if (sysctlbyname("kern.securelevel", NULL, 0, &securelevel,
-		    sizeof(securelevel)))
-			err(1, "Can not set securelevel to %d", securelevel);
-	}
+	if (cmdarg < 0)
+		exit(0);
 	if (username != NULL) {
 		if (Uflag)
 			GET_USER_INFO;
@@ -272,158 +328,328 @@ main(int argc, char **argv)
 		if (p)
 			setenv("TERM", p, 1);
 	}
-	if (execv(argv[3], argv + 3) != 0)
-		err(1, "execv: %s", argv[3]);
-	exit(0);
+	execvp(argv[cmdarg], argv + cmdarg);
+	err(1, "execvp: %s", argv[cmdarg]);
 }
 
 static void
-usage(void)
+add_ip_addr(char **addrp, char *value)
 {
+	int addrlen;
+	char *addr;
+
+	if (!*addrp) {
+		*addrp = strdup(value);
+		if (!*addrp)
+			err(1, "malloc");
+	} else if (value[0]) {
+		addrlen = strlen(*addrp) + strlen(value) + 2;
+		addr = malloc(addrlen);
+		if (!addr)
+			err(1, "malloc");
+		snprintf(addr, addrlen, "%s,%s", *addrp, value);
+		free(*addrp);
+		*addrp = addr;
+	}
+}
 
-	(void)fprintf(stderr, "%s%s%s\n",
-	     "usage: jail [-hi] [-n jailname] [-J jid_file] ",
-	     "[-s securelevel] [-l -u username | -U username] ",
-	     "path hostname [ip[,..]] command ...");
-	exit(1);
+#ifdef INET6
+static void
+add_ip_addr46(char *value)
+{
+	char *p, *np;
+
+	if (!value[0]) {
+		add_ip_addr(&ip4_addr, value);
+		add_ip_addr(&ip6_addr, value);
+		return;
+	}
+	for (p = value;; p = np + 1)
+	{
+		np = strchr(p, ',');
+		if (np)
+			*np = '\0';
+		add_ip_addrinfo(AI_NUMERICHOST, p);
+		if (!np)
+			break;
+	}
 }
+#endif
 
-static int
-add_addresses(struct addrinfo *res0)
+static void
+add_ip_addrinfo(int ai_flags, char *value)
 {
+	struct addrinfo hints, *ai0, *ai;
+	struct in_addr addr4;
 	int error;
-	struct addrinfo *res;
-	struct addr4entry *a4p;
-	struct sockaddr_in *sai;
+	char avalue4[INET_ADDRSTRLEN];
 #ifdef INET6
-	struct addr6entry *a6p;
-	struct sockaddr_in6 *sai6;
+	struct in6_addr addr6;
+	char avalue6[INET6_ADDRSTRLEN];
 #endif
-	int count;
 
-	error = 0;
-	for (res = res0; res && error == 0; res = res->ai_next) {
-		switch (res->ai_family) {
+	/* Look up the hostname (or get the address) */
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_socktype = SOCK_STREAM;
+#ifdef INET6
+	hints.ai_family = PF_UNSPEC;
+#else
+	hints.ai_family = PF_INET;
+#endif
+	hints.ai_flags = ai_flags;
+	error = getaddrinfo(value, NULL, &hints, &ai0);
+	if (error != 0)
+		errx(1, "hostname %s: %s", value, gai_strerror(error));
+	
+	/* Convert the addresses to ASCII so set_param can convert them back. */
+	for (ai = ai0; ai; ai = ai->ai_next)
+		switch (ai->ai_family) {
 		case AF_INET:
-			sai = (struct sockaddr_in *)(void *)res->ai_addr;
-			STAILQ_FOREACH(a4p, &addr4, addr4entries) {
-			    if (bcmp(&sai->sin_addr, &a4p->ip4,
-				sizeof(struct in_addr)) == 0) {
-				    err(1, "Ignoring duplicate IPv4 address.");
-				    break;
-			    }
-			}
-			a4p = (struct addr4entry *) malloc(
-			    sizeof(struct addr4entry));
-			if (a4p == NULL) {
-				error = 1;
-				break;
-			}
-			bzero(a4p, sizeof(struct addr4entry));
-			bcopy(&sai->sin_addr, &a4p->ip4,
-			    sizeof(struct in_addr));
-			if (!STAILQ_EMPTY(&addr4))
-				count = STAILQ_FIRST(&addr4)->count;
-			else
-				count = 0;
-			STAILQ_INSERT_TAIL(&addr4, a4p, addr4entries);
-			STAILQ_FIRST(&addr4)->count = count + 1;
+			memcpy(&addr4, &((struct sockaddr_in *)
+			    (void *)ai->ai_addr)->sin_addr, sizeof(addr4));
+			if (inet_ntop(AF_INET, &addr4, avalue4,
+			    INET_ADDRSTRLEN) == NULL)
+				err(1, "inet_ntop");
+			add_ip_addr(&ip4_addr, avalue4);
 			break;
 #ifdef INET6
 		case AF_INET6:
-			sai6 = (struct sockaddr_in6 *)(void *)res->ai_addr;
-			STAILQ_FOREACH(a6p, &addr6, addr6entries) {
-			    if (bcmp(&sai6->sin6_addr, &a6p->ip6,
-				sizeof(struct in6_addr)) == 0) {
-				    err(1, "Ignoring duplicate IPv6 address.");
-				    break;
-			    }
-			}
-			a6p = (struct addr6entry *) malloc(
-			    sizeof(struct addr6entry));
-			if (a6p == NULL) {
-				error = 1;
-				break;
-			}
-			bzero(a6p, sizeof(struct addr6entry));
-			bcopy(&sai6->sin6_addr, &a6p->ip6,
-			    sizeof(struct in6_addr));
-			if (!STAILQ_EMPTY(&addr6))
-				count = STAILQ_FIRST(&addr6)->count;
-			else
-				count = 0;
-			STAILQ_INSERT_TAIL(&addr6, a6p, addr6entries);
-			STAILQ_FIRST(&addr6)->count = count + 1;
+			memcpy(&addr6, &((struct sockaddr_in6 *)
+			    (void *)ai->ai_addr)->sin6_addr, sizeof(addr6));
+			if (inet_ntop(AF_INET6, &addr6, avalue6,
+			    INET6_ADDRSTRLEN) == NULL)
+				err(1, "inet_ntop");
+			add_ip_addr(&ip6_addr, avalue6);
 			break;
 #endif
-		default:
-			err(1, "Address family %d not supported. Ignoring.\n",
-			    res->ai_family);
-			break;
 		}
-	}
-
-	return (error);
+	freeaddrinfo(ai0);
 }
 
-static struct in_addr *
-copy_addr4(void)
+static void
+quoted_print(FILE *fp, char *str)
 {
-	size_t len;
-	struct in_addr *ip4s, *p, ia;
-	struct addr4entry *a4p;
+	int c, qc;
+	char *p = str;
 
-	if (STAILQ_EMPTY(&addr4))
-		return NULL;
-
-	len = STAILQ_FIRST(&addr4)->count * sizeof(struct in_addr);
-
-	ip4s = p = (struct in_addr *)malloc(len);
-	if (ip4s == NULL)
-	return (NULL);
-
-	bzero(p, len);
-
-	while (!STAILQ_EMPTY(&addr4)) {
-		a4p = STAILQ_FIRST(&addr4);
-		STAILQ_REMOVE_HEAD(&addr4, addr4entries);
-		ia.s_addr = a4p->ip4.s_addr;
-		bcopy(&ia, p, sizeof(struct in_addr));
-		p++;
-		free(a4p);
+	/* An empty string needs quoting. */
+	if (!*p) {
+		fputs("\"\"", fp);
+		return;
 	}
 
-	return (ip4s);
+	/*
+	 * The value will be surrounded by quotes if it contains spaces
+	 * or quotes.
+	 */
+	qc = strchr(p, '\'') ? '"'
+	    : strchr(p, '"') ? '\''
+	    : strchr(p, ' ') || strchr(p, '\t') ? '"'
+	    : 0;
+	if (qc)
+		putc(qc, fp);
+	while ((c = *p++)) {
+		if (c == '\\' || c == qc)
+			putc('\\', fp);
+		putc(c, fp);
+	}
+	if (qc)
+		putc(qc, fp);
 }
 
-#ifdef INET6
-static struct in6_addr *
-copy_addr6(void)
+static void
+set_param(const char *name, char *value)
 {
-	size_t len;
-	struct in6_addr *ip6s, *p;
-	struct addr6entry *a6p;
-
-	if (STAILQ_EMPTY(&addr6))
-		return NULL;
-
-	len = STAILQ_FIRST(&addr6)->count * sizeof(struct in6_addr);
-
-	ip6s = p = (struct in6_addr *)malloc(len);
-	if (ip6s == NULL)
-		return (NULL);
+	struct param *param;
+	char *ep, *p;
+	size_t buflen, mlen;
+	int i, nval, mib[CTL_MAXNAME];
+	struct {
+		int i;
+		char s[MAXPATHLEN];
+	} buf;
+
+	static int paramlistsize;
+
+	/* Separate the name from the value, if not done already. */
+	if (name == NULL) {
+		name = value;
+		if ((value = strchr(value, '=')))
+			*value++ = '\0';
+	}
 
-	bzero(p, len);
+	/* Check for repeat parameters */
+	for (i = 0; i < nparams; i++)
+		if (!strcmp(name, params[i].name.iov_base)) {
+			memcpy(params + i, params + i + 1,
+			    (--nparams - i) * sizeof(struct param));
+			break;
+		}
 
-	while (!STAILQ_EMPTY(&addr6)) {
-		a6p = STAILQ_FIRST(&addr6);
-		STAILQ_REMOVE_HEAD(&addr6, addr6entries);
-		bcopy(&a6p->ip6, p, sizeof(struct in6_addr));
-		p++;
-		free(a6p);
+	/* Make sure there is room for the new param record. */
+	if (!nparams) {
+		paramlistsize = 32;
+		params = malloc(paramlistsize * sizeof(*params));
+		param_values = malloc(paramlistsize * sizeof(*param_values));
+		if (params == NULL || param_values == NULL)
+			err(1, "malloc");
+	} else if (nparams >= paramlistsize) {
+		paramlistsize *= 2;
+		params = realloc(params, paramlistsize * sizeof(*params));
+		param_values = realloc(param_values,
+		    paramlistsize * sizeof(*param_values));
+		if (params == NULL)
+			err(1, "realloc");
 	}
 
-	return (ip6s);
-}
+	/* Look up the paramter. */
+	param_values[nparams] = value;
+	param = params + nparams++;
+	*(const void **)&param->name.iov_base = name;
+	param->name.iov_len = strlen(name) + 1;
+	/* Trivial values - no value or errmsg. */
+	if (value == NULL) {
+		param->value.iov_base = NULL;
+		param->value.iov_len = 0;
+		return;
+	}
+	if (!strcmp(name, "errmsg")) {
+		param->value.iov_base = value;
+		param->value.iov_len = ERRMSG_SIZE;
+		return;
+	}
+	mib[0] = 0;
+	mib[1] = 3;
+	snprintf(buf.s, sizeof(buf.s), SJPARAM ".%s", name);
+	mlen = sizeof(mib) - 2 * sizeof(int);
+	if (sysctl(mib, 2, mib + 2, &mlen, buf.s, strlen(buf.s)) < 0)
+		errx(1, "unknown parameter: %s", name);
+	mib[1] = 4;
+	buflen = sizeof(buf);
+	if (sysctl(mib, (mlen / sizeof(int)) + 2, &buf, &buflen, NULL, 0) < 0)
+		err(1, "sysctl(0.4.%s)", name);
+	/*
+	 * See if this is an array type.
+	 * Treat non-arrays as an array of one.
+	 */
+	p = strchr(buf.s, '\0');
+	nval = 1;
+	if (p - 2 >= buf.s && !strcmp(p - 2, ",a")) {
+		if (value[0] == '\0' ||
+		    (value[0] == '-' && value[1] == '\0')) {
+			param->value.iov_base = value;
+			param->value.iov_len = 0;
+			return;
+		}
+		p[-2] = 0;
+		for (p = strchr(value, ','); p; p = strchr(p + 1, ',')) {
+			*p = '\0';
+			nval++;
+		}
+	}
+	
+	/* Set the values according to the parameter type. */
+	switch (buf.i & CTLTYPE) {
+	case CTLTYPE_INT:
+	case CTLTYPE_UINT:
+		param->value.iov_len = nval * sizeof(int);
+		break;
+	case CTLTYPE_LONG:
+	case CTLTYPE_ULONG:
+		param->value.iov_len = nval * sizeof(long);
+		break;
+	case CTLTYPE_STRUCT:
+		if (!strcmp(buf.s, "S,in_addr"))
+			param->value.iov_len = nval * sizeof(struct in_addr);
+#ifdef INET6
+		else if (!strcmp(buf.s, "S,in6_addr"))
+			param->value.iov_len = nval * sizeof(struct in6_addr);
+#endif
+		else
+			errx(1, "%s: unknown parameter structure (%s)",
+			    name, buf.s);
+		break;
+	case CTLTYPE_STRING:
+		if (!strcmp(name, "path")) {
+			param->value.iov_base = malloc(MAXPATHLEN);
+			if (param->value.iov_base == NULL)
+				err(1, "malloc");
+			if (realpath(value, param->value.iov_base) == NULL)
+				err(1, "%s: realpath(%s)", name, value);
+			if (chdir(param->value.iov_base) != 0)
+				err(1, "chdir: %s",
+				    (char *)param->value.iov_base);
+		} else
+			param->value.iov_base = value;
+		param->value.iov_len = strlen(param->value.iov_base) + 1;
+		return;
+	default:
+		errx(1, "%s: unknown parameter type %d (%s)",
+		    name, buf.i, buf.s);
+	}
+	param->value.iov_base = malloc(param->value.iov_len);
+	for (i = 0; i < nval; i++) {
+		switch (buf.i & CTLTYPE) {
+		case CTLTYPE_INT:
+			((int *)param->value.iov_base)[i] =
+			    strtol(value, &ep, 10);
+			if (ep[0] != '\0')
+				errx(1, "%s: non-integer value \"%s\"",
+				    name, value);
+			break;
+		case CTLTYPE_UINT:
+			((unsigned *)param->value.iov_base)[i] =
+			    strtoul(value, &ep, 10);
+			if (ep[0] != '\0')
+				errx(1, "%s: non-integer value \"%s\"",
+				    name, value);
+			break;
+		case CTLTYPE_LONG:
+			((long *)param->value.iov_base)[i] =
+			    strtol(value, &ep, 10);
+			if (ep[0] != '\0')
+			    errx(1, "%s: non-integer value \"%s\"",
+				name, value);
+			break;
+		case CTLTYPE_ULONG:
+			((unsigned long *)param->value.iov_base)[i] =
+			    strtoul(value, &ep, 10);
+			if (ep[0] != '\0')
+			    errx(1, "%s: non-integer value \"%s\"",
+				name, value);
+			break;
+		case CTLTYPE_STRUCT:
+			if (!strcmp(buf.s, "S,in_addr")) {
+				if (inet_pton(AF_INET, value,
+				    &((struct in_addr *)
+				    param->value.iov_base)[i]) != 1)
+					errx(1, "%s: not an IPv4 address: %s",
+					    name, value);
+			}
+#ifdef INET6
+			else if (!strcmp(buf.s, "S,in6_addr")) {
+				if (inet_pton(AF_INET6, value,
+				    &((struct in6_addr *)
+				    param->value.iov_base)[i]) != 1)
+					errx(1, "%s: not an IPv6 address: %s",
+					    name, value);
+			}
 #endif
+		}
+		if (i > 0)
+			value[-1] = ',';
+		value = strchr(value, '\0') + 1;
+	}
+}
 
+static void
+usage(void)
+{
+
+	(void)fprintf(stderr,
+	    "usage: jail [-d] [-h] [-i] [-J jid_file] "
+			"[-l -u username | -U username]\n"
+	    "            [-c | -m] param=value ... [command=command ...]\n"
+	    "       jail [-r jail]\n");
+	exit(1);
+}
diff --git a/usr.sbin/jexec/Makefile b/usr.sbin/jexec/Makefile
index 049ccd4..2bf817c 100644
--- a/usr.sbin/jexec/Makefile
+++ b/usr.sbin/jexec/Makefile
@@ -6,6 +6,4 @@ DPADD=	${LIBUTIL}
 LDADD=	-lutil
 WARNS?=	6
 
-CFLAGS+= -DSUPPORT_OLD_XPRISON
-
 .include <bsd.prog.mk>
diff --git a/usr.sbin/jexec/jexec.8 b/usr.sbin/jexec/jexec.8
index bdda23d..a98af67 100644
--- a/usr.sbin/jexec/jexec.8
+++ b/usr.sbin/jexec/jexec.8
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 29, 2008
+.Dd May 27, 2009
 .Dt JEXEC 8
 .Os
 .Sh NAME
@@ -34,36 +34,18 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl u Ar username | Fl U Ar username
-.Op Fl n Ar jailname
-.Ar jid command ...
+.Ar jail command ...
 .Sh DESCRIPTION
 The
 .Nm
 utility executes
 .Ar command
-inside the jail identified by either
-.Ar jailname
-or
-.Ar jid
-or both.
-.Pp
-If the jail cannot be identified uniquely by the given parameters,
-an error message is printed.
-.Nm
-will also check the state of the jail (once supported) to be
-.Dv ALIVE
-and ignore jails in other states.
-The mandatory argument
-.Ar jid
-is the unique jail identifier as given by
-.Xr jls 8 .
-In case you only want to match on other criteria, give an empty string.
+inside the
+.Ar jail
+identified by its jid or name.
 .Pp
 The following options are available:
 .Bl -tag -width indent
-.It Fl n Ar jailname
-The name of the jail, if given upon creation of the jail.
-This is not the hostname of the jail.
 .It Fl u Ar username
 The user name from host environment as whom the
 .Ar command
diff --git a/usr.sbin/jexec/jexec.c b/usr.sbin/jexec/jexec.c
index 7237b5a..e86657bf 100644
--- a/usr.sbin/jexec/jexec.c
+++ b/usr.sbin/jexec/jexec.c
@@ -29,12 +29,16 @@
 
 #include <sys/param.h>
 #include <sys/jail.h>
+#include <sys/socket.h>
 #include <sys/sysctl.h>
+#include <sys/uio.h>
 
+#include <arpa/inet.h>
 #include <netinet/in.h>
 
 #include <err.h>
 #include <errno.h>
+#include <limits.h>
 #include <login_cap.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -44,153 +48,6 @@
 
 static void	usage(void);
 
-#ifdef SUPPORT_OLD_XPRISON
-static
-char *lookup_xprison_v1(void *p, char *end, int *id)
-{
-	struct xprison_v1 *xp;
-
-	if (id == NULL)
-		errx(1, "Internal error. Invalid ID pointer.");
-
-	if ((char *)p + sizeof(struct xprison_v1) > end)
-		errx(1, "Invalid length for jail");
-
-	xp = (struct xprison_v1 *)p;
-
-	*id = xp->pr_id;
-	return ((char *)(xp + 1));
-}
-#endif
-
-static
-char *lookup_xprison_v3(void *p, char *end, int *id, char *jailname)
-{
-	struct xprison *xp;
-	char *q;
-	int ok;
-
-	if (id == NULL)
-		errx(1, "Internal error. Invalid ID pointer.");
-
-	if ((char *)p + sizeof(struct xprison) > end)
-		errx(1, "Invalid length for jail");
-
-	xp = (struct xprison *)p;
-	ok = 1;
-
-	/* Jail state and name. */
-	if (xp->pr_state < 0 || xp->pr_state >=
-	    (int)((sizeof(prison_states) / sizeof(struct prison_state))))
-		errx(1, "Invalid jail state.");
-	else if (xp->pr_state != PRISON_STATE_ALIVE)
-		ok = 0;
-	if (jailname != NULL) {
-		if (xp->pr_name[0] == '\0')
-			ok = 0;
-		else if (strcmp(jailname, xp->pr_name) != 0)
-			ok = 0;
-	}
-
-	q = (char *)(xp + 1);
-	/* IPv4 addresses. */
-	q += (xp->pr_ip4s * sizeof(struct in_addr));
-	if ((char *)q > end)
-		errx(1, "Invalid length for jail");
-	/* IPv6 addresses. */
-	q += (xp->pr_ip6s * sizeof(struct in6_addr));
-	if ((char *)q > end)
-		errx(1, "Invalid length for jail");
-
-	if (ok)
-		*id = xp->pr_id;
-	return (q);
-}
-
-static int
-lookup_jail(int jid, char *jailname)
-{
-	size_t i, j, len;
-	void *p, *q;
-	int version, id, xid, count;
-
-	if (sysctlbyname("security.jail.list", NULL, &len, NULL, 0) == -1)
-		err(1, "sysctlbyname(): security.jail.list");
-
-	j = len;
-	for (i = 0; i < 4; i++) {
-		if (len == 0)
-			return (-1);
-		p = q = malloc(len);
-		if (p == NULL)
-			err(1, "malloc()");
-
-		if (sysctlbyname("security.jail.list", q, &len, NULL, 0) == -1) {
-			if (errno == ENOMEM) {
-				free(p);
-				p = NULL;
-				len += j;
-				continue;
-			}
-			err(1, "sysctlbyname(): security.jail.list");
-		}
-		break;
-	}
-	if (p == NULL)
-		err(1, "sysctlbyname(): security.jail.list");
-	if (len < sizeof(int))
-		errx(1, "This is no prison. Kernel and userland out of sync?");
-	version = *(int *)p;
-	if (version > XPRISON_VERSION)
-		errx(1, "Sci-Fi prison. Kernel/userland out of sync?");
-
-	count = 0;
-	xid = -1;
-	for (; q != NULL && (char *)q + sizeof(int) < (char *)p + len;) {
-		version = *(int *)q;
-		if (version > XPRISON_VERSION)
-			errx(1, "Sci-Fi prison. Kernel/userland out of sync?");
-		id = -1;
-		switch (version) {
-#ifdef SUPPORT_OLD_XPRISON
-		case 1:
-			if (jailname != NULL)
-				errx(1, "Version 1 prisons did not "
-				    "support jail names.");
-			q = lookup_xprison_v1(q, (char *)p + len, &id);
-			break;
-		case 2:
-			errx(1, "Version 2 was used by multi-IPv4 jail "
-			    "implementations that never made it into the "
-			    "official kernel.");
-			/* NOTREACHED */
-			break;
-#endif
-		case 3:
-			q = lookup_xprison_v3(q, (char *)p + len, &id, jailname);
-			break;
-		default:
-			errx(1, "Prison unknown. Kernel/userland out of sync?");
-			/* NOTREACHED */
-			break;
-		}
-		/* Possible match; see if we have a jail ID to match as well.  */
-		if (id > 0 && (jid <= 0 || id == jid)) {
-			xid = id;
-			count++;
-		}
-	}
-
-	free(p);
-
-	if (count == 1)
-		return (xid);
-	else if (count > 1)
-		errx(1, "Could not uniquely identify the jail.");
-	else
-		return (-1);
-}
-
 #define GET_USER_INFO do {						\
 	pwd = getpwnam(username);					\
 	if (pwd == NULL) {						\
@@ -210,21 +67,20 @@ lookup_jail(int jid, char *jailname)
 int
 main(int argc, char *argv[])
 {
+	struct iovec params[2];
 	int jid;
 	login_cap_t *lcap = NULL;
 	struct passwd *pwd = NULL;
 	gid_t groups[NGROUPS];
 	int ch, ngroups, uflag, Uflag;
-	char *jailname, *username;
-
+	char *ep, *username;
 	ch = uflag = Uflag = 0;
-	jailname = username = NULL;
-	jid = -1;
+	username = NULL;
 
-	while ((ch = getopt(argc, argv, "i:n:u:U:")) != -1) {
+	while ((ch = getopt(argc, argv, "nu:U:")) != -1) {
 		switch (ch) {
 		case 'n':
-			jailname = optarg;
+			/* Specified name, now unused */
 			break;
 		case 'u':
 			username = optarg;
@@ -242,22 +98,20 @@ main(int argc, char *argv[])
 	argv += optind;
 	if (argc < 2)
 		usage();
-	if (strlen(argv[0]) > 0) {
-		jid = (int)strtol(argv[0], NULL, 10);
-		if (errno)
-			err(1, "Unable to parse jail ID.");
-	}
-	if (jid <= 0 && jailname == NULL) {
-		fprintf(stderr, "Neither jail ID nor jail name given.\n");
-		usage();
-	}
 	if (uflag && Uflag)
 		usage();
 	if (uflag)
 		GET_USER_INFO;
-	jid = lookup_jail(jid, jailname);
-	if (jid <= 0)
-		errx(1, "Cannot identify jail.");
+	jid = strtoul(argv[0], &ep, 10);
+	if (!*argv[0] || *ep) {
+		*(const void **)&params[0].iov_base = "name";
+		params[0].iov_len = sizeof("name");
+		params[1].iov_base = argv[0];
+		params[1].iov_len = strlen(argv[0]) + 1;
+		jid = jail_get(params, 2, 0);
+		if (jid < 0)
+			errx(1, "Unknown jail: %s", argv[0]);
+	}
 	if (jail_attach(jid) == -1)
 		err(1, "jail_attach(): %d", jid);
 	if (chdir("/") == -1)
@@ -283,8 +137,7 @@ static void
 usage(void)
 {
 
-	fprintf(stderr, "%s%s\n",
-		"usage: jexec [-u username | -U username]",
-		" [-n jailname] jid command ...");
+	fprintf(stderr, "%s\n",
+		"usage: jexec [-u username | -U username] jail command ...");
 	exit(1); 
 }
diff --git a/usr.sbin/jls/Makefile b/usr.sbin/jls/Makefile
index 01294bd..3968946 100644
--- a/usr.sbin/jls/Makefile
+++ b/usr.sbin/jls/Makefile
@@ -4,6 +4,4 @@ PROG=	jls
 MAN=	jls.8
 WARNS?=	6
 
-CFLAGS+= -DSUPPORT_OLD_XPRISON
-
 .include <bsd.prog.mk>
diff --git a/usr.sbin/jls/jls.8 b/usr.sbin/jls/jls.8
index aff9848..c0eed8d 100644
--- a/usr.sbin/jls/jls.8
+++ b/usr.sbin/jls/jls.8
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 29, 2008
+.Dd May 27, 2009
 .Dt JLS 8
 .Os
 .Sh NAME
@@ -33,38 +33,68 @@
 .Nd "list jails"
 .Sh SYNOPSIS
 .Nm
-.Op Fl av
+.Op Fl dhnqsv
+.Op Fl j Ar jail
+.Op Ar parameter ...
 .Sh DESCRIPTION
 The
 .Nm
-utility lists all jails.
-By default only active jails are listed.
+utility lists all active jails, or the specified jail.
+Each jail is represented by one row which contains space-separated values of
+the listed
+.Ar parameters ,
+including the pseudo-parameter
+.Va all
+which will show all available jail parameters.
+A list of available parameters can be retrieved via
+.Dq Nm sysctl Fl d Va security.jail.param .
+See
+.Xr jail 8
+for a description of some core parameters.
 .Pp
-The options are as follows:
-.Bl -tag -width ".Fl a"
-.It Fl a
-Show jails in all states, not only active ones.
-.It Fl v
-Show more verbose information.
-This also lists cpusets, jail state, multi-IP, etc. instead of the
-classic single-IP jail output.
-.El
+If no
+.Ar parameters
+are given, the following four columns will be printed:
+jail identifier (jid), IP address (ip4.addr), hostname (host.hostname),
+and path (path).
 .Pp
-Each jail is represented by rows which, depending on
-.Fl v ,
-contain the following columns:
-.Bl -item -offset indent -compact
-.It
-jail identifier (JID), hostname and path
-.It
-jail state and name
-.It
-jail cpuset
-.It
-followed by one IP adddress per line.
+The following options are available:
+.Bl -tag -width indent
+.It Fl d
+List
+.Va dying
+as well as active jails.
+.It Fl h
+Print a header line containing the parameters listed.
+If no parameters are given on the command line, the default output always
+contains a header.
+.It Fl n
+Print parameters in
+.Dq name=value
+format, where each parameter is preceded by its name.
+This option is ignored for the default four-column output.
+.It Fl q
+Put quotes around parameters if they contain spaces or quotes, or are
+the empty string.
+.It Fl c
+Print parameters suitable for passing to
+.Xr jail 8 ,
+skipping read-only and unused parameters.
+Implies
+.Fl nq .
+.It Fl v
+Print a multiple-line summary per jail, with the following parameters:
+jail identifier (jid), hostname (host.hostname), path (path),
+jail name (name), jail state (dying), cpuset ID (cpuset),
+IP address(es) (ip4.addr and ip6.addr).
+.It Fl j Ar jail
+The jid or name of the
+.Ar jail
+to list.
+Without this option, all active jails will be listed.
 .El
 .Sh SEE ALSO
-.Xr jail 2 ,
+.Xr jail_get 2 ,
 .Xr jail 8 ,
 .Xr jexec 8
 .Sh HISTORY
@@ -72,3 +102,5 @@ The
 .Nm
 utility was added in
 .Fx 5.1 .
+Extensible jail parameters were introduced in
+.Fx 8.0 .
diff --git a/usr.sbin/jls/jls.c b/usr.sbin/jls/jls.c
index 95f17d4..cc8dabd 100644
--- a/usr.sbin/jls/jls.c
+++ b/usr.sbin/jls/jls.c
@@ -1,6 +1,7 @@
 /*-
  * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
  * Copyright (c) 2008 Bjoern A. Zeeb <bz@FreeBSD.org>
+ * Copyright (c) 2009 James Gritton <jamie@FreeBSD.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -23,18 +24,20 @@
  * 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.
- *
- * $FreeBSD$
  */
 
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
 #include <sys/param.h>
-#include <sys/types.h>
 #include <sys/jail.h>
+#include <sys/socket.h>
 #include <sys/sysctl.h>
+#include <sys/uio.h>
 
-#include <sys/socket.h>
-#include <netinet/in.h>
 #include <arpa/inet.h>
+#include <netinet/in.h>
+
 #include <err.h>
 #include <errno.h>
 #include <limits.h>
@@ -43,215 +46,718 @@
 #include <string.h>
 #include <unistd.h>
 
-#define	FLAG_A		0x00001
-#define	FLAG_V		0x00002
+#define	SJPARAM		"security.jail.param"
+#define	ARRAY_SLOP	5
+
+#define	CTLTYPE_BOOL	(CTLTYPE + 1)
+#define	CTLTYPE_NOBOOL	(CTLTYPE + 2)
+#define	CTLTYPE_IPADDR	(CTLTYPE + 3)
+#define	CTLTYPE_IP6ADDR	(CTLTYPE + 4)
+
+#define	PARAM_KEY	0x01
+#define	PARAM_USER	0x02
+#define	PARAM_ARRAY	0x04
+#define	PARAM_OPT	0x08
+#define	PARAM_WR	0x10
+
+#define	PRINT_DEFAULT	0x01
+#define	PRINT_HEADER	0x02
+#define	PRINT_NAMEVAL	0x04
+#define	PRINT_QUOTED	0x08
+#define	PRINT_SKIP	0x10
+#define	PRINT_VERBOSE	0x20
+
+struct param {
+	char	*name;
+	void	*value;
+	size_t	 size;
+	int	 type;
+	unsigned flags;
+	int	 noparent;
+};
+
+struct iovec2 {
+	struct iovec	name;
+	struct iovec	value;
+};
+
+static struct param *params;
+static int nparams;
+static char errmsg[256];
+
+static int add_param(const char *name, void *value, unsigned flags);
+static int get_param(const char *name, struct param *param);
+static int sort_param(const void *a, const void *b);
+static char *noname(const char *name);
+static char *nononame(const char *name);
+static int print_jail(int pflags, int jflags);
+static void quoted_print(char *str, int len);
 
-#ifdef SUPPORT_OLD_XPRISON
-static
-char *print_xprison_v1(void *p, char *end, unsigned flags)
+int
+main(int argc, char **argv)
 {
-	struct xprison_v1 *xp;
-	struct in_addr in;
-
-	if ((char *)p + sizeof(struct xprison_v1) > end)
-		errx(1, "Invalid length for jail");
-
-	xp = (struct xprison_v1 *)p;
-	if (flags & FLAG_V) {
-		printf("%6d  %-29.29s %.74s\n",
-			xp->pr_id, xp->pr_host, xp->pr_path);
-		/* We are not printing an empty line here for state and name. */
-		/* We are not printing an empty line here for cpusetid. */
-		/* IPv4 address. */
-		in.s_addr = htonl(xp->pr_ip);
-		printf("%6s  %-15.15s\n", "", inet_ntoa(in));
+	char *dot, *ep, *jname, *nname;
+	int c, i, jflags, jid, lastjid, pflags, spc;
+
+	jname = NULL;
+	pflags = jflags = jid = 0;
+	while ((c = getopt(argc, argv, "adj:hnqsv")) >= 0)
+		switch (c) {
+		case 'a':
+		case 'd':
+			jflags |= JAIL_DYING;
+			break;
+		case 'j':
+			jid = strtoul(optarg, &ep, 10);
+			if (!*optarg || *ep)
+				jname = optarg;
+			break;
+		case 'h':
+			pflags = (pflags & ~PRINT_SKIP) | PRINT_HEADER;
+			break;
+		case 'n':
+			pflags = (pflags & ~PRINT_VERBOSE) | PRINT_NAMEVAL;
+			break;
+		case 'q':
+			pflags |= PRINT_QUOTED;
+			break;
+		case 's':
+			pflags = (pflags & ~(PRINT_HEADER | PRINT_VERBOSE)) |
+			    PRINT_NAMEVAL | PRINT_QUOTED | PRINT_SKIP;
+			break;
+		case 'v':
+			pflags = (pflags & ~(PRINT_NAMEVAL | PRINT_SKIP)) |
+			    PRINT_VERBOSE;
+			break;
+		default:
+			errx(1, "usage: jls [-dhnqv] [-j jail] [param ...]");
+		}
+
+	/* Add the parameters to print. */
+	if (optind == argc) {
+		if (pflags & PRINT_VERBOSE) {
+			add_param("jid", NULL, PARAM_USER);
+			add_param("host.hostname", NULL, PARAM_USER);
+			add_param("path", NULL, PARAM_USER);
+			add_param("name", NULL, PARAM_USER);
+			add_param("dying", NULL, PARAM_USER);
+			add_param("cpuset", NULL, PARAM_USER);
+			add_param("ip4.addr", NULL, PARAM_USER);
+			add_param("ip6.addr", NULL, PARAM_USER | PARAM_OPT);
+		} else {
+			pflags = (pflags &
+			    ~(PRINT_NAMEVAL | PRINT_SKIP | PRINT_VERBOSE)) |
+			    PRINT_DEFAULT;
+			add_param("jid", NULL, PARAM_USER);
+			add_param("ip4.addr", NULL, PARAM_USER);
+			add_param("host.hostname", NULL, PARAM_USER);
+			add_param("path", NULL, PARAM_USER);
+		}
+	} else
+		while (optind < argc)
+			add_param(argv[optind++], NULL, PARAM_USER);
+
+	if (pflags & PRINT_SKIP) {
+		/* Check for parameters with boolean parents. */
+		for (i = 0; i < nparams; i++) {
+			if ((params[i].flags & PARAM_USER) &&
+			    (dot = strchr(params[i].name, '.'))) {
+				*dot = 0;
+				nname = noname(params[i].name);
+				*dot = '.';
+				params[i].noparent =
+				    add_param(nname, NULL, PARAM_OPT);
+				free(nname);
+			}
+		}
+	}
+
+	/* Add the index key and errmsg parameters. */
+	if (jid != 0)
+		add_param("jid", &jid, PARAM_KEY);
+	else if (jname != NULL)
+		add_param("name", jname, PARAM_KEY);
+	else
+		add_param("lastjid", &lastjid, PARAM_KEY);
+	add_param("errmsg", errmsg, PARAM_KEY);
+
+	/* Print a header line if requested. */
+	if (pflags & PRINT_VERBOSE)
+		printf("   JID  Hostname                      Path\n"
+		       "        Name                          State\n"
+		       "        CPUSetID\n"
+		       "        IP Address(es)\n");
+	else if (pflags & PRINT_DEFAULT)
+		printf("   JID  IP Address      "
+		       "Hostname                      Path\n");
+	else if (pflags & PRINT_HEADER) {
+		for (i = spc = 0; i < nparams; i++)
+			if (params[i].flags & PARAM_USER) {
+				if (spc)
+					putchar(' ');
+				else
+					spc = 1;
+				fputs(params[i].name, stdout);
+			}
+		putchar('\n');
+	}
+
+	/* Fetch the jail(s) and print the paramters. */
+	if (jid != 0 || jname != NULL) {
+		if (print_jail(pflags, jflags) < 0) {
+			if (errmsg[0])
+				errx(1, "%s", errmsg);
+			err(1, "jail_get");
+		}
 	} else {
-		printf("%6d  %-15.15s %-29.29s %.74s\n",
-		    xp->pr_id, inet_ntoa(in), xp->pr_host, xp->pr_path);
+		for (lastjid = 0;
+		     (lastjid = print_jail(pflags, jflags)) >= 0; )
+			;
+		if (errno != 0 && errno != ENOENT) {
+			if (errmsg[0])
+				errx(1, "%s", errmsg);
+			err(1, "jail_get");
+		}
 	}
 
-	return ((char *)(xp + 1));
+	return (0);
 }
-#endif
 
-static
-char *print_xprison_v3(void *p, char *end, unsigned flags)
+static int
+add_param(const char *name, void *value, unsigned flags)
 {
-	struct xprison *xp;
-	struct in_addr *iap, in;
-	struct in6_addr *ia6p;
-	char buf[INET6_ADDRSTRLEN];
-	const char *state;
-	char *q;
-	uint32_t i;
-
-	if ((char *)p + sizeof(struct xprison) > end)
-		errx(1, "Invalid length for jail");
-	xp = (struct xprison *)p;
-
-	if (xp->pr_state < 0 || xp->pr_state >= (int)
-	    ((sizeof(prison_states) / sizeof(struct prison_state))))
-		state = "(bogus)";
-	else
-		state = prison_states[xp->pr_state].state_name;
-
-	/* See if we should print non-ACTIVE jails. No? */
-	if ((flags & FLAG_A) == 0 && strcmp(state, "ALIVE")) {
-		q = (char *)(xp + 1);
-		q += (xp->pr_ip4s * sizeof(struct in_addr));
-		if (q > end)
-			errx(1, "Invalid length for jail");
-		q += (xp->pr_ip6s * sizeof(struct in6_addr));
-		if (q > end)
-			errx(1, "Invalid length for jail");
-		return (q);
+	struct param *param;
+	char *nname;
+	size_t mlen1, mlen2, buflen;
+	int mib1[CTL_MAXNAME], mib2[CTL_MAXNAME - 2];
+	int i, tnparams;
+	char buf[MAXPATHLEN];
+
+	static int paramlistsize;
+
+	/* The pseudo-parameter "all" scans the list of available parameters. */
+	if (!strcmp(name, "all")) {
+		tnparams = nparams;
+		mib1[0] = 0;
+		mib1[1] = 2;
+		mlen1 = CTL_MAXNAME - 2;
+		if (sysctlnametomib(SJPARAM, mib1 + 2, &mlen1) < 0)
+			err(1, "sysctlnametomib(" SJPARAM ")");
+		for (;;) {
+			/* Get the next parameter. */
+			mlen2 = sizeof(mib2);
+			if (sysctl(mib1, mlen1 + 2, mib2, &mlen2, NULL, 0) < 0)
+				err(1, "sysctl(0.2)");
+			if (mib2[0] != mib1[2] || mib2[1] != mib1[3] ||
+			    mib2[2] != mib1[4])
+				break;
+			/* Convert it to an ascii name. */
+			memcpy(mib1 + 2, mib2, mlen2);
+			mlen1 = mlen2 / sizeof(int);
+			mib1[1] = 1;
+			buflen = sizeof(buf);
+			if (sysctl(mib1, mlen1 + 2, buf, &buflen, NULL, 0) < 0)
+				err(1, "sysctl(0.1)");
+			add_param(buf + sizeof(SJPARAM), NULL, flags);
+			/*
+			 * Convert nobool parameters to bool if their
+			 * counterpart is a node, ortherwise discard them.
+			 */
+			param = &params[nparams - 1];
+			if (param->type == CTLTYPE_NOBOOL) {
+				nname = nononame(param->name);
+				if (get_param(nname, param) >= 0 &&
+				    param->type != CTLTYPE_NODE) {
+					free(nname);
+					nparams--;
+				} else {
+					free(param->name);
+					param->name = nname;
+					param->type = CTLTYPE_BOOL;
+					param->size = sizeof(int);
+					param->value = NULL;
+				}
+			}
+			mib1[1] = 2;
+		}
+
+		qsort(params + tnparams, (size_t)(nparams - tnparams),
+		    sizeof(struct param), sort_param);
+		return -1;
+	}
+
+	/* Check for repeat parameters. */
+	for (i = 0; i < nparams; i++)
+		if (!strcmp(name, params[i].name)) {
+			params[i].value = value;
+			params[i].flags |= flags;
+			return i;
+		}
+
+	/* Make sure there is room for the new param record. */
+	if (!nparams) {
+		paramlistsize = 32;
+		params = malloc(paramlistsize * sizeof(*params));
+		if (params == NULL)
+			err(1, "malloc");
+	} else if (nparams >= paramlistsize) {
+		paramlistsize *= 2;
+		params = realloc(params, paramlistsize * sizeof(*params));
+		if (params == NULL)
+			err(1, "realloc");
+	}
+
+	/* Look up the parameter. */
+	param = params + nparams++;
+	memset(param, 0, sizeof *param);
+	param->name = strdup(name);
+	if (param->name == NULL)
+		err(1, "strdup");
+	param->flags = flags;
+	param->noparent = -1;
+	/* We have to know about pseudo-parameters without asking. */
+	if (!strcmp(param->name, "lastjid")) {
+		param->type = CTLTYPE_INT;
+		param->size = sizeof(int);
+		goto got_type;
+	}
+	if (!strcmp(param->name, "errmsg")) {
+		param->type = CTLTYPE_STRING;
+		param->size = sizeof(errmsg);
+		goto got_type;
+	}
+	if (get_param(name, param) < 0) {
+		if (errno != ENOENT)
+			err(1, "sysctl(0.3.%s)", name);
+		/* See if this the "no" part of an existing boolean. */
+		if ((nname = nononame(name))) {
+			i = get_param(nname, param);
+			free(nname);
+			if (i >= 0 && param->type == CTLTYPE_BOOL) {
+				param->type = CTLTYPE_NOBOOL;
+				goto got_type;
+			}
+		}
+		if (flags & PARAM_OPT) {
+			nparams--;
+			return -1;
+		}
+		errx(1, "unknown parameter: %s", name);
+	}
+	if (param->type == CTLTYPE_NODE) {
+		/*
+		 * A node isn't normally a parameter, but may be a boolean
+		 * if its "no" counterpart exists.
+		 */
+		nname = noname(name);
+		i = get_param(nname, param);
+		free(nname);
+		if (i >= 0 && param->type == CTLTYPE_NOBOOL) {
+			param->type = CTLTYPE_BOOL;
+			goto got_type;
+		}
+		errx(1, "unknown parameter: %s", name);
 	}
 
-	if (flags & FLAG_V)
-		printf("%6d  %-29.29s %.74s\n",
-			xp->pr_id, xp->pr_host, xp->pr_path);
-
-	/* Jail state and name. */
-	if (flags & FLAG_V)
-		printf("%6s  %-29.29s %.74s\n",
-		    "", (xp->pr_name[0] != '\0') ? xp->pr_name : "", state);
-
-	/* cpusetid. */
-	if (flags & FLAG_V)
-		printf("%6s  %-6d\n",
-		    "", xp->pr_cpusetid);
-
-	q = (char *)(xp + 1);
-	/* IPv4 addresses. */
-	iap = (struct in_addr *)(void *)q;
-	q += (xp->pr_ip4s * sizeof(struct in_addr));
-	if (q > end)
-		errx(1, "Invalid length for jail");
-	in.s_addr = 0;
-	for (i = 0; i < xp->pr_ip4s; i++) {
-		if (i == 0 || flags & FLAG_V)
-			in.s_addr = iap[i].s_addr;
-		if (flags & FLAG_V)
-			printf("%6s  %-15.15s\n", "", inet_ntoa(in));
+ got_type:
+	param->value = value;
+	return param - params;
+}
+
+static int
+get_param(const char *name, struct param *param)
+{
+	char *p;
+	size_t buflen, mlen;
+	int mib[CTL_MAXNAME];
+	struct {
+		int i;
+		char s[MAXPATHLEN];
+	} buf;
+
+	/* Look up the MIB. */
+	mib[0] = 0;
+	mib[1] = 3;
+	snprintf(buf.s, sizeof(buf.s), SJPARAM ".%s", name);
+	mlen = sizeof(mib) - 2 * sizeof(int);
+	if (sysctl(mib, 2, mib + 2, &mlen, buf.s, strlen(buf.s)) < 0)
+		return (-1);
+	/* Get the type and size. */
+	mib[1] = 4;
+	buflen = sizeof(buf);
+	if (sysctl(mib, (mlen / sizeof(int)) + 2, &buf, &buflen, NULL, 0) < 0)
+		err(1, "sysctl(0.4.%s)", name);
+	param->type = buf.i & CTLTYPE;
+	if (buf.i & (CTLFLAG_WR | CTLFLAG_TUN))
+		param->flags |= PARAM_WR;
+	p = strchr(buf.s, '\0');
+	if (p - 2 >= buf.s && !strcmp(p - 2, ",a")) {
+		p[-2] = 0;
+		param->flags |= PARAM_ARRAY;
 	}
-	/* IPv6 addresses. */
-	ia6p = (struct in6_addr *)(void *)q;
-	q += (xp->pr_ip6s * sizeof(struct in6_addr));
-	if (q > end)
-		errx(1, "Invalid length for jail");
-	for (i = 0; i < xp->pr_ip6s; i++) {
-		if (flags & FLAG_V) {
-			inet_ntop(AF_INET6, &ia6p[i], buf, sizeof(buf));
-			printf("%6s  %s\n", "", buf);
+	switch (param->type) {
+	case CTLTYPE_INT:
+		/* An integer parameter might be a boolean. */
+		if (buf.s[0] == 'B')
+			param->type = buf.s[1] == 'N'
+			    ? CTLTYPE_NOBOOL : CTLTYPE_BOOL;
+	case CTLTYPE_UINT:
+		param->size = sizeof(int);
+		break;
+	case CTLTYPE_LONG:
+	case CTLTYPE_ULONG:
+		param->size = sizeof(long);
+		break;
+	case CTLTYPE_STRUCT:
+		if (!strcmp(buf.s, "S,in_addr")) {
+			param->type = CTLTYPE_IPADDR;
+			param->size = sizeof(struct in_addr);
+		} else if (!strcmp(buf.s, "S,in6_addr")) {
+			param->type = CTLTYPE_IP6ADDR;
+			param->size = sizeof(struct in6_addr);
 		}
+		break;
+	case CTLTYPE_STRING:
+		buf.s[0] = 0;
+		sysctl(mib + 2, mlen / sizeof(int), buf.s, &buflen, NULL, 0);
+		param->size = strtoul(buf.s, NULL, 10);
+		if (param->size == 0)
+			param->size = BUFSIZ;
 	}
+	return (0);
+}
 
-	/* If requested print the old style single line version. */
-	if (!(flags & FLAG_V))
-		printf("%6d  %-15.15s %-29.29s %.74s\n",
-		    xp->pr_id, (in.s_addr) ? inet_ntoa(in) : "",
-		    xp->pr_host, xp->pr_path);
+static int
+sort_param(const void *a, const void *b)
+{
+	const struct param *parama, *paramb;
+	char *ap, *bp;
 
-	return (q);
+	/* Put top-level parameters first. */
+	parama = a;
+	paramb = b;
+	ap = strchr(parama->name, '.');
+	bp = strchr(paramb->name, '.');
+	if (ap && !bp)
+		return (1);
+	if (bp && !ap)
+		return (-1);
+	return (strcmp(parama->name, paramb->name));
 }
 
-static void
-usage(void)
+static char *
+noname(const char *name)
 {
+	char *nname, *p;
 
-	(void)fprintf(stderr, "usage: jls [-av]\n");
-	exit(1);
+	nname = malloc(strlen(name) + 3);
+	if (nname == NULL)
+		err(1, "malloc");
+	p = strrchr(name, '.');
+	if (p != NULL)
+		sprintf(nname, "%.*s.no%s", (int)(p - name), name, p + 1);
+	else
+		sprintf(nname, "no%s", name);
+	return nname;
 }
 
-int
-main(int argc, char *argv[])
-{ 
-	int ch, version;
-	unsigned flags;
-	size_t i, j, len;
-	void *p, *q;
+static char *
+nononame(const char *name)
+{
+	char *nname, *p;
 
-	flags = 0;
-	while ((ch = getopt(argc, argv, "av")) != -1) {
-		switch (ch) {
-		case 'a':
-			flags |= FLAG_A;
-			break;
-		case 'v':
-			flags |= FLAG_V;
-			break;
-		default:
-			usage();
+	p = strrchr(name, '.');
+	if (strncmp(p ? p + 1 : name, "no", 2))
+		return NULL;
+	nname = malloc(strlen(name) - 1);
+	if (nname == NULL)
+		err(1, "malloc");
+	if (p != NULL)
+		sprintf(nname, "%.*s.%s", (int)(p - name), name, p + 3);
+	else
+		strcpy(nname, name + 2);
+	return nname;
+}
+
+static int
+print_jail(int pflags, int jflags)
+{
+	char *nname;
+	int i, ai, jid, count, sanity, spc;
+	char ipbuf[INET6_ADDRSTRLEN];
+
+	static struct iovec2 *iov, *aiov;
+	static int narray, nkey;
+
+	/* Set up the parameter list(s) the first time around. */
+	if (iov == NULL) {
+		iov = malloc(nparams * sizeof(struct iovec2));
+		if (iov == NULL)
+			err(1, "malloc");
+		for (i = narray = 0; i < nparams; i++) {
+			iov[i].name.iov_base = params[i].name;
+			iov[i].name.iov_len = strlen(params[i].name) + 1;
+			iov[i].value.iov_base = params[i].value;
+			iov[i].value.iov_len =
+			    params[i].type == CTLTYPE_STRING &&
+			    params[i].value != NULL &&
+			    ((char *)params[i].value)[0] != '\0'
+			    ? strlen(params[i].value) + 1 : params[i].size;
+			if (params[i].flags & (PARAM_KEY | PARAM_ARRAY)) {
+				narray++;
+				if (params[i].flags & PARAM_KEY)
+					nkey++;
+			}
+		}
+		if (narray > nkey) {
+			aiov = malloc(narray * sizeof(struct iovec2));
+			if (aiov == NULL)
+				err(1, "malloc");
+			for (i = ai = 0; i < nparams; i++)
+				if (params[i].flags &
+				    (PARAM_KEY | PARAM_ARRAY))
+					aiov[ai++] = iov[i];
 		}
 	}
-	argc -= optind;
-	argv += optind;
-
-	if (sysctlbyname("security.jail.list", NULL, &len, NULL, 0) == -1)
-		err(1, "sysctlbyname(): security.jail.list");
-
-	j = len;
-	for (i = 0; i < 4; i++) {
-		if (len <= 0)
-			exit(0);	
-		p = q = malloc(len);
-		if (p == NULL)
-			err(1, "malloc()");
-
-		if (sysctlbyname("security.jail.list", q, &len, NULL, 0) == -1) {
-			if (errno == ENOMEM) {
-				free(p);
-				p = NULL;
-				len += j;
-				continue;
+	/* If there are array parameters, find their sizes. */
+	if (aiov != NULL) {
+		for (ai = 0; ai < narray; ai++)
+			if (aiov[ai].value.iov_base == NULL)
+				aiov[ai].value.iov_len = 0;
+		if (jail_get((struct iovec *)aiov, 2 * narray, jflags) < 0)
+			return (-1);
+	}
+	/* Allocate storage for all parameters. */
+	for (i = ai = 0; i < nparams; i++) {
+		if (params[i].flags & (PARAM_KEY | PARAM_ARRAY)) {
+			if (params[i].flags & PARAM_ARRAY) {
+				iov[i].value.iov_len = aiov[ai].value.iov_len +
+				    ARRAY_SLOP * params[i].size;
+				iov[i].value.iov_base =
+				    malloc(iov[i].value.iov_len);
 			}
-			err(1, "sysctlbyname(): security.jail.list");
-		}
-		break;
+			ai++;
+		} else
+			iov[i].value.iov_base = malloc(params[i].size);
+		if (iov[i].value.iov_base == NULL)
+			err(1, "malloc");
+		if (params[i].value == NULL)
+			memset(iov[i].value.iov_base, 0, iov[i].value.iov_len);
 	}
-	if (p == NULL)
-		err(1, "sysctlbyname(): security.jail.list");
-	if (len < sizeof(int))
-		errx(1, "This is no prison. Kernel and userland out of sync?");
-	version = *(int *)p;
-	if (version > XPRISON_VERSION)
-		errx(1, "Sci-Fi prison. Kernel/userland out of sync?");
-
-	if (flags & FLAG_V) {
-		printf("   JID  Hostname                      Path\n");
-		printf("        Name                          State\n");
-		printf("        CPUSetID\n");
-		printf("        IP Address(es)\n");
-	} else {
-		printf("   JID  IP Address      Hostname"
-		    "                      Path\n");
+	/*
+	 * Get the actual prison.  If there are array elements, retry a few
+	 * times in case the size changed from under us.
+	 */
+	if ((jid = jail_get((struct iovec *)iov, 2 * nparams, jflags)) < 0) {
+		if (errno != EINVAL || aiov == NULL || errmsg[0])
+			return (-1);
+		for (sanity = 0;; sanity++) {
+			if (sanity == 10)
+				return (-1);
+			for (ai = 0; ai < narray; ai++)
+				if (params[i].flags & PARAM_ARRAY)
+					aiov[ai].value.iov_len = 0;
+			if (jail_get((struct iovec *)iov, 2 * narray, jflags) <
+			    0)
+				return (-1);
+			for (i = ai = 0; i < nparams; i++) {
+				if (!(params[i].flags &
+				    (PARAM_KEY | PARAM_ARRAY)))
+					continue;
+				if (params[i].flags & PARAM_ARRAY) {
+					iov[i].value.iov_len =
+					    aiov[ai].value.iov_len +
+					    ARRAY_SLOP * params[i].size;
+					iov[i].value.iov_base =
+					    realloc(iov[i].value.iov_base,
+					    iov[i].value.iov_len);
+					if (iov[i].value.iov_base == NULL)
+						err(1, "malloc");
+				}
+				ai++;
+			}
+		}
 	}
-	for (; q != NULL && (char *)q + sizeof(int) < (char *)p + len;) {
-		version = *(int *)q;
-		if (version > XPRISON_VERSION)
-			errx(1, "Sci-Fi prison. Kernel/userland out of sync?");
-		switch (version) {
-#ifdef SUPPORT_OLD_XPRISON
-		case 1:
-			q = print_xprison_v1(q, (char *)p + len, flags);
-			break;
-		case 2:
-			errx(1, "Version 2 was used by multi-IPv4 jail "
-			    "implementations that never made it into the "
-			    "official kernel.");
-			/* NOTREACHED */
-			break;
-#endif
-		case 3:
-			q = print_xprison_v3(q, (char *)p + len, flags);
-			break;
-		default:
-			errx(1, "Prison unknown. Kernel/userland out of sync?");
-			/* NOTREACHED */
-			break;
+	if (pflags & PRINT_VERBOSE) {
+		printf("%6d  %-29.29s %.74s\n"
+		       "%6s  %-29.29s %.74s\n"
+		       "%6s  %-6d\n",
+		    *(int *)iov[0].value.iov_base,
+		    (char *)iov[1].value.iov_base,
+		    (char *)iov[2].value.iov_base,
+		    "",
+		    (char *)iov[3].value.iov_base,
+		    *(int *)iov[4].value.iov_base ? "DYING" : "ACTIVE",
+		    "",
+		    *(int *)iov[5].value.iov_base);
+		count = iov[6].value.iov_len / sizeof(struct in_addr);
+		for (ai = 0; ai < count; ai++)
+			if (inet_ntop(AF_INET,
+			    &((struct in_addr *)iov[6].value.iov_base)[ai],
+			    ipbuf, sizeof(ipbuf)) == NULL)
+				err(1, "inet_ntop");
+			else
+				printf("%6s  %-15.15s\n", "", ipbuf);
+		if (!strcmp(params[7].name, "ip6.addr")) {
+			count = iov[7].value.iov_len / sizeof(struct in6_addr);
+			for (ai = 0; ai < count; ai++)
+				if (inet_ntop(AF_INET6, &((struct in_addr *)
+				    iov[7].value.iov_base)[ai],
+				    ipbuf, sizeof(ipbuf)) == NULL)
+					err(1, "inet_ntop");
+				else
+					printf("%6s  %-15.15s\n", "", ipbuf);
 		}
+	} else if (pflags & PRINT_DEFAULT)
+		printf("%6d  %-15.15s %-29.29s %.74s\n",
+		    *(int *)iov[0].value.iov_base,
+		    iov[1].value.iov_len == 0 ? "-"
+		    : inet_ntoa(*(struct in_addr *)iov[1].value.iov_base),
+		    (char *)iov[2].value.iov_base,
+		    (char *)iov[3].value.iov_base);
+	else {
+		for (i = spc = 0; i < nparams; i++) {
+			if (!(params[i].flags & PARAM_USER))
+				continue;
+			if ((pflags & PRINT_SKIP) &&
+			    ((!(params[i].flags & PARAM_WR)) ||
+			     (params[i].noparent >= 0 &&
+			      *(int *)iov[params[i].noparent].value.iov_base)))
+				continue;
+			if (spc)
+				putchar(' ');
+			else
+				spc = 1;
+			if (pflags & PRINT_NAMEVAL) {
+				/*
+				 * Generally "name=value", but for booleans
+				 * either "name" or "noname".
+				 */
+				switch (params[i].type) {
+				case CTLTYPE_BOOL:
+					if (*(int *)iov[i].value.iov_base)
+						printf("%s", params[i].name);
+					else {
+						nname = noname(params[i].name);
+						printf("%s", nname);
+						free(nname);
+					}
+					break;
+				case CTLTYPE_NOBOOL:
+					if (*(int *)iov[i].value.iov_base)
+						printf("%s", params[i].name);
+					else {
+						nname =
+						    nononame(params[i].name);
+						printf("%s", nname);
+						free(nname);
+					}
+					break;
+				default:
+					printf("%s=", params[i].name);
+				}
+			}
+			count = params[i].flags & PARAM_ARRAY
+			    ? iov[i].value.iov_len / params[i].size : 1;
+			if (count == 0) {
+				if (pflags & PRINT_QUOTED)
+					printf("\"\"");
+				else if (!(pflags & PRINT_NAMEVAL))
+					putchar('-');
+			}
+			for (ai = 0; ai < count; ai++) {
+				if (ai > 0)
+					putchar(',');
+				switch (params[i].type) {
+				case CTLTYPE_INT:
+					printf("%d", ((int *)
+					    iov[i].value.iov_base)[ai]);
+					break;
+				case CTLTYPE_UINT:
+					printf("%u", ((int *)
+					    iov[i].value.iov_base)[ai]);
+					break;
+				case CTLTYPE_IPADDR:
+					if (inet_ntop(AF_INET,
+					    &((struct in_addr *)
+					    iov[i].value.iov_base)[ai],
+					    ipbuf, sizeof(ipbuf)) == NULL)
+						err(1, "inet_ntop");
+					else
+						printf("%s", ipbuf);
+					break;
+				case CTLTYPE_IP6ADDR:
+					if (inet_ntop(AF_INET6,
+					    &((struct in6_addr *)
+					    iov[i].value.iov_base)[ai],
+					    ipbuf, sizeof(ipbuf)) == NULL)
+						err(1, "inet_ntop");
+					else
+						printf("%s", ipbuf);
+					break;
+				case CTLTYPE_LONG:
+					printf("%ld", ((long *)
+					    iov[i].value.iov_base)[ai]);
+				case CTLTYPE_ULONG:
+					printf("%lu", ((long *)
+					    iov[i].value.iov_base)[ai]);
+					break;
+				case CTLTYPE_STRING:
+					if (pflags & PRINT_QUOTED)
+						quoted_print((char *)
+						    iov[i].value.iov_base,
+						    params[i].size);
+					else
+						printf("%.*s",
+						    (int)params[i].size,
+						    (char *)
+						    iov[i].value.iov_base);
+					break;
+				case CTLTYPE_BOOL:
+				case CTLTYPE_NOBOOL:
+					if (!(pflags & PRINT_NAMEVAL))
+						printf(((int *)
+						    iov[i].value.iov_base)[ai]
+						    ? "true" : "false");
+				}
+			}
+		}
+		putchar('\n');
 	}
+	for (i = 0; i < nparams; i++)
+		if (params[i].value == NULL)
+			free(iov[i].value.iov_base);
+	return (jid);
+}
+
+static void
+quoted_print(char *str, int len)
+{
+	int c, qc;
+	char *p = str;
+	char *ep = str + len;
 
-	free(p);
-	exit(0);
+	/* An empty string needs quoting. */
+	if (!*p) {
+		fputs("\"\"", stdout);
+		return;
+	}
+
+	/*
+	 * The value will be surrounded by quotes if it contains spaces
+	 * or quotes.
+	 */
+	qc = strchr(p, '\'') ? '"'
+	    : strchr(p, '"') ? '\''
+	    : strchr(p, ' ') || strchr(p, '\t') ? '"'
+	    : 0;
+	if (qc)
+		putchar(qc);
+	while (p < ep && (c = *p++)) {
+		if (c == '\\' || c == qc)
+			putchar('\\');
+		putchar(c);
+	}
+	if (qc)
+		putchar(qc);
 }