--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docs/jexec.c	Fri Aug 15 15:43:38 2008 +0000
@@ -0,0 +1,82 @@
+/*-
+ * Copyright (c) 2004 Joerg Sonnenberger <joerg@bec.de>
+ * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
+ * 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: src/usr.sbin/jexec/jexec.c,v 1.2 2003/07/04 19:14:27 bmilekic Exp $
+ * $DragonFly: src/usr.sbin/jexec/jexec.c,v 1.1 2005/01/31 22:29:59 joerg Exp $
+ */
+
+#include <sys/param.h>
+#include <sys/jail.h>
+
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static int	getjailid(const char *str);
+static void	usage(void);
+
+int
+main(int argc, char **argv)
+{
+	int jid;
+
+	if (argc < 3)
+		usage();
+	jid = getjailid(argv[1]);
+	if (jail_attach(jid) == -1)
+		err(1, "jail_attach(%d) failed", jid);
+	if (chdir("/") == -1)
+		err(1, "chdir(\"/\") failed");
+	if (execvp(argv[2], argv + 2) == -1)
+		err(1, "execvp(%s) failed", argv[2]);
+	exit(0);
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: jexec jid command [...]\n");
+	exit(1); 
+}
+
+static int
+getjailid(const char *str)
+{
+	long v;
+	char *ep;
+
+	errno = 0;
+	v = strtol(str, &ep, 10);
+	if (v < INT_MIN || v > INT_MAX || errno == ERANGE)
+		errc(1, ERANGE, "invalid jail id", str);
+	if (ep == str || *ep != '\0')
+		errx(1, "cannot parse jail id: %s.", str);
+
+	return((int)(v));
+}
+