diff -ruN /usr/src/sys/sys/sysctl.h.orig sys/sys/sysctl.h
--- /usr/src/sys/sys/sysctl.h.orig	Fri Apr  7 10:40:38 2006
+++ sys/sys/sysctl.h	Mon Jun  5 20:53:21 2006
@@ -430,6 +430,7 @@
 #define	KERN_PROC_RGID		10	/* by real group id */
 #define	KERN_PROC_GID		11	/* by effective group id */
 #define	KERN_PROC_PATHNAME	12	/* path to executable */
+#define	KERN_PROC_JID		13	/* by effective jail id */
 #define	KERN_PROC_INC_THREAD	0x10	/*
 					 * modifier for pid, pgrp, tty,
 					 * uid, ruid, gid, rgid and proc
diff -ruN /usr/src/sys/kern/kern_proc.c.orig sys/kern/kern_proc.c
--- /usr/src/sys/kern/kern_proc.c.orig	Tue Jan 17 15:24:37 2006
+++ sys/kern/kern_proc.c	Tue Jun  6 10:19:28 2006
@@ -1084,6 +1084,15 @@
 				}
 				break;
 
+			case KERN_PROC_JID:
+				if (p->p_ucred == NULL || !jailed(p->p_ucred) ||
+				    jailed(curthread->td_ucred) ||
+				    p->p_ucred->cr_prison->pr_id != (int)name[0]) {
+					PROC_UNLOCK(p);
+					continue;
+				}
+				break;
+
 			case KERN_PROC_PROC:
 				break;
 
@@ -1300,6 +1309,9 @@
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PID, pid, CTLFLAG_RD, 
 	sysctl_kern_proc, "Process table");
 
+static SYSCTL_NODE(_kern_proc, KERN_PROC_JID, jid, CTLFLAG_RD, 
+	sysctl_kern_proc, "Process table");
+
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PROC, proc, CTLFLAG_RD,
 	sysctl_kern_proc, "Return process table, no threads");
 
@@ -1335,6 +1347,9 @@
 	CTLFLAG_RD, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_PID | KERN_PROC_INC_THREAD), pid_td,
+	CTLFLAG_RD, sysctl_kern_proc, "Process table");
+
+static SYSCTL_NODE(_kern_proc, (KERN_PROC_JID | KERN_PROC_INC_THREAD), jid_td,
 	CTLFLAG_RD, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_PROC | KERN_PROC_INC_THREAD), proc_td,
diff -ruN /usr/src/usr.bin/fstat/fstat.c.orig usr.bin/fstat/fstat.c
--- /usr/src/usr.bin/fstat/fstat.c.orig	Tue Jan 17 15:24:43 2006
+++ usr.bin/fstat/fstat.c	Tue Jun  6 07:59:06 2006
@@ -119,6 +119,7 @@
 
 int 	fsflg,	/* show files on same filesystem as file(s) argument */
 	pflg,	/* show files open by a particular pid */
+	jflg,	/* show files open by a particular jid */
 	uflg;	/* show files open by a particular (effective) user */
 int 	checkfile; /* true if restricting to particular files or filesystems */
 int	nflg;	/* (numerical) display f.s. and rdev as dev_t */
@@ -166,7 +167,7 @@
 	arg = 0;
 	what = KERN_PROC_ALL;
 	nlistf = memf = NULL;
-	while ((ch = getopt(argc, argv, "fmnp:u:vN:M:")) != -1)
+	while ((ch = getopt(argc, argv, "fmnp:u:vN:M:j:")) != -1)
 		switch((char)ch) {
 		case 'f':
 			fsflg = 1;
@@ -201,6 +202,16 @@
 			what = KERN_PROC_UID;
 			arg = passwd->pw_uid;
 			break;
+		case 'j':
+			if (jflg++)
+				usage();
+			if (!isdigit(*optarg)) {
+				warnx("-j requires a jail id");
+				usage();
+			}
+			what = KERN_PROC_JID;
+			arg = atoi(optarg);
+			break;
 		case 'v':
 			vflg = 1;
 			break;
@@ -942,6 +953,6 @@
 usage(void)
 {
 	(void)fprintf(stderr,
- "usage: fstat [-fmnv] [-M core] [-N system] [-p pid] [-u user] [file ...]\n");
+ "usage: fstat [-fmnv] [-M core] [-N system] [-p pid] [-j jid] [-u user] [file ...]\n");
 	exit(1);
 }
diff -ruN /usr/src/lib/libkvm/kvm_proc.c.orig lib/libkvm/kvm_proc.c
--- /usr/src/lib/libkvm/kvm_proc.c.orig	Fri Jun 24 08:37:04 2005
+++ lib/libkvm/kvm_proc.c	Mon Jun  5 21:00:49 2006
@@ -203,6 +203,11 @@
 			if (kp->ki_ruid != (uid_t)arg)
 				continue;
 			break;
+
+		case KERN_PROC_JID:
+			if (kp->ki_jid != (int)arg)
+				continue;
+			break;
 		}
 		/*
 		 * We're going to add another proc to the set.  If this