From bf5bfe45abafa8fdd4e3622caba07996e593ee28 Mon Sep 17 00:00:00 2001
From: Peter Wemm <peter@FreeBSD.org>
Date: Wed, 24 Jan 1996 18:11:23 +0000
Subject: [PATCH] proc.h: Add PHOLD()/PRELE() macros to ensure the U area is
 not swapped while doing ptrace/procfs in it. ptrace.h: uncomment
 PT_ATTACH/PT_DETACH, I am committing code to do this.

---
 sys/sys/proc.h   | 9 ++++++++-
 sys/sys/ptrace.h | 4 +---
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 49b1b525b3d8..c276b879aa31 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)proc.h	8.8 (Berkeley) 1/21/94
- * $Id: proc.h,v 1.17 1995/03/16 18:16:22 bde Exp $
+ * $Id: proc.h,v 1.18 1995/07/13 08:48:03 davidg Exp $
  */
 
 #ifndef _SYS_PROC_H_
@@ -234,6 +234,13 @@ struct	pcred {
 		FREE(s, M_SESSION);					\
 }
 
+/* hold process U-area in memory, normally for ptrace/procfs work */
+#define PHOLD(p) {							\
+	if ((p)->p_lock++ == 0 && ((p)->p_flag & P_INMEM) == 0)	\
+		faultin(p);						\
+}
+#define PRELE(p)	(--(p)->p_lock)
+
 extern struct proc *pidhash[];		/* In param.c. */
 extern struct pgrp *pgrphash[];		/* In param.c. */
 extern struct proc *curproc;		/* Current running proc. */
diff --git a/sys/sys/ptrace.h b/sys/sys/ptrace.h
index 9c6c15945a9b..55b176e0ceeb 100644
--- a/sys/sys/ptrace.h
+++ b/sys/sys/ptrace.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ptrace.h	8.2 (Berkeley) 1/4/94
- * $Id: ptrace.h,v 1.3 1994/08/08 13:00:27 davidg Exp $
+ * $Id: ptrace.h,v 1.4 1995/03/16 18:16:23 bde Exp $
  */
 
 #ifndef	_SYS_PTRACE_H_
@@ -48,10 +48,8 @@
 #define	PT_KILL		8	/* kill the child process */
 #define	PT_STEP		9	/* single step the child */
 
-#ifdef notdef
 #define	PT_ATTACH	10	/* trace some running process */
 #define	PT_DETACH	11	/* stop tracing a process */
-#endif
 
 #define	PT_FIRSTMACH	32	/* for machine-specific requests */
 #include <machine/ptrace.h>	/* machine-specific requests, if any */