Added sysctl security.jail.jailed.

It returns 1 is process is inside of jail and 0 if it is not.
Information if we are in jail or not is not a secret, there is plenty of
ways to discover it. Many people are using own hack to check this and
this will be a legal way from now on.

It will be great if our starting scripts will take advantage of this sysctl
to allow clean "boot" inside jail.

Approved by:	rwatson, scottl (mentor)

1 files changed, 13 insertions, 0 deletions

diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c
index b867935..5893a3e 100644
--- a/sys/kern/kern_jail.c
+++ b/sys/kern/kern_jail.c
@@ -490,3 +490,16 @@ retry:
 
 SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD,
     NULL, 0, sysctl_jail_list, "S", "List of active jails");
+
+static int
+sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
+{
+	int error, injail;
+
+	injail = jailed(req->td->td_ucred);
+	error = SYSCTL_OUT(req, &injail, sizeof(injail));
+
+	return (error);
+}
+SYSCTL_PROC(_security_jail, OID_AUTO, jailed, CTLTYPE_INT | CTLFLAG_RD,
+    NULL, 0, sysctl_jail_jailed, "I", "Process in jail?");