Add sysctl variables for the Linuxulator. These reside under `compat.linux' as

discussed on current.

The following variables are defined (for now):

    osname (defaults to "Linux")
        Allow users to change the name of the OS as returned by uname(2),
        specially added for all those Linux Netscape users and statistics
        maniacs :-) We now have what we all wanted!

    osrelease (defaults to "2.2.5")
        Allow users to change the version of the OS as returned by uname(2).
        Since -current supports glibc2.1 now, change the default to 2.2.5
        (was 2.0.36).

    oss_version (defaults to 198144 [0x030600])
        This one will be used by the OSS_GETVERSION ioctl (PR 12917) which I
        can commit now that we have the MIB. The default version number is the
        lowest version possible with the current 'encoding'.

A note about imprisoned processes (see jail(2)):
  These variables are copy-on-write (as suggested by phk). This means that
  imprisoned processes will use the system wide value unless it is written/set
  by the process. From that moment on, a copy local to the prison will be
  used.

A note about the implementation:
  I choose to add a single pointer to struct prison, because I didn't like the
  idea of changing struct prison every time I come up with a new variable. As
  a side effect, the extra storage is only needed when a variable is set from
  within the prison. This also minimizes kernel bloat when the Linuxulator is
  not used; both compiled in or as a module.

Reviewed by: bde (first version only) and phk

1 files changed, 5 insertions, 2 deletions

diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 91a7461..10a54ac 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_exit.c	8.7 (Berkeley) 2/12/94
- * $Id: kern_exit.c,v 1.80 1999/04/28 11:36:52 phk Exp $
+ * $Id: kern_exit.c,v 1.81 1999/06/07 20:37:29 msmith Exp $
  */
 
 #include "opt_compat.h"
@@ -508,8 +508,11 @@ loop:
 			/*
 			 * Destroy empty prisons
 			 */
-			if (p->p_prison && !--p->p_prison->pr_ref)
+			if (p->p_prison && !--p->p_prison->pr_ref) {
+				if (p->p_prison->pr_linux != NULL)
+					FREE(p->p_prison->pr_linux, M_PRISON);
 				FREE(p->p_prison, M_PRISON);
+			}
 
 			/*
 			 * Finally finished with old proc entry.