From b8fa61d129429757d1ba66349f7a57b0f76f2c7e Mon Sep 17 00:00:00 2001
From: Bruce Evans <bde@FreeBSD.org>
Date: Fri, 28 Mar 1997 12:56:07 +0000
Subject: [PATCH] Added a setjmp() and a longjmp() so that an unexpected trap
 inside ddb isn't necessarily fatal.  You can now do silly things like `call
 vprint' and `show map' without losing control.

---
 sys/amd64/amd64/db_interface.c | 17 ++++++++++++++++-
 sys/i386/i386/db_interface.c   | 17 ++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/sys/amd64/amd64/db_interface.c b/sys/amd64/amd64/db_interface.c
index 6e56a9f523b6..c286027d53bd 100644
--- a/sys/amd64/amd64/db_interface.c
+++ b/sys/amd64/amd64/db_interface.c
@@ -23,7 +23,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- *	$Id$
+ *	$Id: db_interface.c,v 1.26 1997/02/22 09:32:14 peter Exp $
  */
 
 /*
@@ -44,6 +44,7 @@
 #include <vm/pmap.h>
 
 #include <ddb/ddb.h>
+
 #include <setjmp.h>
 
 static jmp_buf *db_nofault = 0;
@@ -53,6 +54,9 @@ extern void	gdb_handle_exception __P((db_regs_t *, int, int));
 
 db_regs_t ddb_regs;
 
+static jmp_buf	db_global_jmpbuf;
+static int	db_global_jmpbuf_valid;
+
 #ifdef __GNUC__
 #define	rss() ({u_short ss; __asm __volatile("movl %%ss,%0" : "=r" (ss)); ss;})
 #endif
@@ -107,6 +111,14 @@ kdb_trap(type, code, regs)
 		}
 	}
 
+	/*
+	 * This handles unexpected traps in ddb commands, including calls to
+	 * non-ddb functions.  db_nofault only applies to memory accesses by
+	 * internal ddb commands.
+	 */
+	if (db_global_jmpbuf_valid)
+	    longjmp(db_global_jmpbuf, 1);
+
 	/*
 	 * XXX We really should switch to a local stack here.
 	 */
@@ -122,10 +134,13 @@ kdb_trap(type, code, regs)
 
 	cnpollc(TRUE);
 
+	(void) setjmp(db_global_jmpbuf);
+	db_global_jmpbuf_valid = TRUE;
 	if (ddb_mode)
 	    db_trap(type, code);
 	else
 	    gdb_handle_exception(&ddb_regs, type, code);
+	db_global_jmpbuf_valid = FALSE;
 
 	cnpollc(FALSE);
 
diff --git a/sys/i386/i386/db_interface.c b/sys/i386/i386/db_interface.c
index 6e56a9f523b6..c286027d53bd 100644
--- a/sys/i386/i386/db_interface.c
+++ b/sys/i386/i386/db_interface.c
@@ -23,7 +23,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- *	$Id$
+ *	$Id: db_interface.c,v 1.26 1997/02/22 09:32:14 peter Exp $
  */
 
 /*
@@ -44,6 +44,7 @@
 #include <vm/pmap.h>
 
 #include <ddb/ddb.h>
+
 #include <setjmp.h>
 
 static jmp_buf *db_nofault = 0;
@@ -53,6 +54,9 @@ extern void	gdb_handle_exception __P((db_regs_t *, int, int));
 
 db_regs_t ddb_regs;
 
+static jmp_buf	db_global_jmpbuf;
+static int	db_global_jmpbuf_valid;
+
 #ifdef __GNUC__
 #define	rss() ({u_short ss; __asm __volatile("movl %%ss,%0" : "=r" (ss)); ss;})
 #endif
@@ -107,6 +111,14 @@ kdb_trap(type, code, regs)
 		}
 	}
 
+	/*
+	 * This handles unexpected traps in ddb commands, including calls to
+	 * non-ddb functions.  db_nofault only applies to memory accesses by
+	 * internal ddb commands.
+	 */
+	if (db_global_jmpbuf_valid)
+	    longjmp(db_global_jmpbuf, 1);
+
 	/*
 	 * XXX We really should switch to a local stack here.
 	 */
@@ -122,10 +134,13 @@ kdb_trap(type, code, regs)
 
 	cnpollc(TRUE);
 
+	(void) setjmp(db_global_jmpbuf);
+	db_global_jmpbuf_valid = TRUE;
 	if (ddb_mode)
 	    db_trap(type, code);
 	else
 	    gdb_handle_exception(&ddb_regs, type, code);
+	db_global_jmpbuf_valid = FALSE;
 
 	cnpollc(FALSE);