[src/trunk]: src/sys/ddb Don't overflow DDB command history. Coyote Point ch...

[tls <tls%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/50dff3cd249b
branches:  trunk
changeset: 757460:50dff3cd249b
user:      tls <tls%NetBSD.org@localhost>
date:      Mon Aug 30 19:23:25 2010 +0000

description:
Don't overflow DDB command history.  Coyote Point changelist description:

DDB is flakey.  The command history wanders past the bounds.  Way
past.  When it hits some boolean that indicates a.out format symbol
tables are to be used, and here is the pointer to the function, the
call thru the NULL function pointer renders the debug session entirely
unsatisfactory, outcome wise.

diffstat:

 sys/ddb/db_input.c |  62 +++++++++++++++++++++++++++++------------------------
 1 files changed, 34 insertions(+), 28 deletions(-)

diffs (124 lines):

diff -r a508809563eb -r 50dff3cd249b sys/ddb/db_input.c
--- a/sys/ddb/db_input.c        Mon Aug 30 18:29:52 2010 +0000
+++ b/sys/ddb/db_input.c        Mon Aug 30 19:23:25 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_input.c,v 1.23 2009/03/07 22:02:17 ad Exp $ */
+/*     $NetBSD: db_input.c,v 1.24 2010/08/30 19:23:25 tls Exp $        */
 
 /*
  * Mach Operating System
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_input.c,v 1.23 2009/03/07 22:02:17 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_input.c,v 1.24 2010/08/30 19:23:25 tls Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddbparam.h"
@@ -63,7 +63,6 @@
 static char    *db_le;         /* one past last character */
 #if DDB_HISTORY_SIZE != 0
 static char    db_history[DDB_HISTORY_SIZE];   /* start of history buffer */
-static int     db_history_size = DDB_HISTORY_SIZE;/* size of history buffer */
 static char    *db_history_curr = db_history;  /* start of current line */
 static char    *db_history_last = db_history;  /* start of last line */
 static char    *db_history_prev = (char *) 0;  /* start of previous line */
@@ -131,21 +130,31 @@
 }
 
 #if DDB_HISTORY_SIZE != 0
-#define INC_DB_CURR() \
-       do { \
-                db_history_curr++; \
-                if (db_history_curr > db_history + db_history_size - 1) \
-                        db_history_curr = db_history; \
-       } while (/*CONSTCOND*/ 0)
-#define DEC_DB_CURR() \
-       do { \
-                db_history_curr--; \
-                if (db_history_curr < db_history) \
-                    db_history_curr = db_history + \
-                    db_history_size - 1; \
-       } while (/*CONSTCOND*/ 0)
+
+#define INC_DB_CURR() do {                                             \
+       ++db_history_curr;                                              \
+       if (db_history_curr > db_history + DDB_HISTORY_SIZE - 1)        \
+           db_history_curr = db_history;                               \
+    } while (0)
+#define DEC_DB_CURR() do {                                             \
+       --db_history_curr;                                              \
+       if (db_history_curr < db_history)                               \
+           db_history_curr = db_history + DDB_HISTORY_SIZE - 1;        \
+    } while (0)
 #endif
 
+static inline void db_hist_put(int c)
+{
+       KASSERT(&db_history[0]  <= db_history_last);
+       KASSERT(db_history_last <= &db_history[DDB_HISTORY_SIZE-1]);
+
+       *db_history_last++ = c;
+
+       if (db_history_last > &db_history[DDB_HISTORY_SIZE-1])
+           db_history_last = db_history;
+}
+       
+
 /* returns true at end-of-line */
 static int
 db_inputchar(int c)
@@ -239,7 +248,7 @@
                        for (p = db_history_curr, db_le = db_lbuf_start;
                             *p; ) {
                                *db_le++ = *p++;
-                               if (p == db_history + db_history_size) {
+                               if (p >= db_history + DDB_HISTORY_SIZE) {
                                        p = db_history;
                                }
                        }
@@ -261,8 +270,7 @@
                                for (p = db_history_curr,
                                     db_le = db_lbuf_start; *p;) {
                                        *db_le++ = *p++;
-                                       if (p == db_history +
-                                           db_history_size) {
+                                       if (p >= db_history + DDB_HISTORY_SIZE) {
                                                p = db_history;
                                        }
                                }
@@ -291,10 +299,10 @@
                             pc != db_le && *pp; pp++, pc++) {
                                if (*pp != *pc)
                                        break;
-                               if (++pp == db_history + db_history_size) {
+                               if (++pp >= db_history + DDB_HISTORY_SIZE) {
                                        pp = db_history;
                                }
-                               if (++pc == db_history + db_history_size) {
+                               if (++pc >= db_history + DDB_HISTORY_SIZE) {
                                        pc = db_history;
                                }
                        }
@@ -307,15 +315,13 @@
                }
                if (db_le != db_lbuf_start) {
                        char *p;
+
                        db_history_prev = db_history_last;
-                       for (p = db_lbuf_start; p != db_le; p++) {
-                               *db_history_last++ = *p;
-                               if (db_history_last == db_history +
-                                   db_history_size) {
-                                       db_history_last = db_history;
-                               }
+
+                       for (p = db_lbuf_start; p != db_le; ) {
+                               db_hist_put(*p++);
                        }
-                       *db_history_last++ = '\0';
+                       db_hist_put(0);
                }
                db_history_curr = db_history_last;
 #endif