From 0b96b98294901442de8196e21fff7c5fd79750ef Mon Sep 17 00:00:00 2001
From: Justus Winter <justus@gnupg.org>
Date: Sat, 12 Aug 2017 13:29:56 +0200
Subject: ddb: Add magic variable $mapXX.

Maps '$mapXX' to a VM map structure address.  @var{xx} is a task
identification number printed by a @code{show all tasks} command.

* ddb/db_task_thread.c (db_get_map): New function.
* ddb/db_task_thread.h (db_get_map): New declaration.
* ddb/db_variables.c (db_vars): Add new variable.
* doc/mach.texi: Document this.
---
 ddb/db_task_thread.c | 25 +++++++++++++++++++++++++
 ddb/db_task_thread.h |  6 ++++++
 ddb/db_variables.c   |  2 ++
 doc/mach.texi        |  5 +++++
 4 files changed, 38 insertions(+)

diff --git a/ddb/db_task_thread.c b/ddb/db_task_thread.c
index 7927e674..f7fbb805 100644
--- a/ddb/db_task_thread.c
+++ b/ddb/db_task_thread.c
@@ -303,4 +303,29 @@ db_get_task_thread(
 	return;
 }
 
+/*
+ * convert $mapXXX type DDB variable to map address
+ */
+void
+db_get_map(struct db_variable *vp,
+	   db_expr_t *valuep,
+	   int flag,
+	   db_var_aux_param_t ap)
+{
+  task_t task;
+
+  if (flag != DB_VAR_GET) {
+    db_error("Cannot set to $map variable\n");
+    /* NOTREACHED */
+  }
+
+  if ((task = db_lookup_task_id(ap->suffix[0])) == TASK_NULL) {
+    db_printf("no such map($map%d)\n", ap->suffix[0]);
+    db_error(0);
+    /* NOTREACHED */
+  }
+
+  *valuep = (db_expr_t) task->map;
+}
+
 #endif /* MACH_KDB */
diff --git a/ddb/db_task_thread.h b/ddb/db_task_thread.h
index cbb36802..55ab4f53 100644
--- a/ddb/db_task_thread.h
+++ b/ddb/db_task_thread.h
@@ -64,4 +64,10 @@ db_get_task_thread(
 	int			flag,
 	db_var_aux_param_t	ap);
 
+extern void
+db_get_map(struct db_variable *vp,
+	   db_expr_t *valuep,
+	   int flag,
+	   db_var_aux_param_t ap);
+
 #endif  /* _DDB_DB_TASK_THREAD_H_ */
diff --git a/ddb/db_variables.c b/ddb/db_variables.c
index 4442ccbc..0fd9bad0 100644
--- a/ddb/db_variables.c
+++ b/ddb/db_variables.c
@@ -61,6 +61,8 @@ struct db_variable db_vars[] = {
 	{ "thread",	0,			db_set_default_thread	},
 	{ "task",	0,			db_get_task_thread,
 	  1,		2,			-1,	-1		},
+	{ "map",	0,			db_get_map,
+	  1,		1,			-1,	-1		},
 	{ "work",	&db_work[0],		FCN_NULL,
 	  1,		1,			0,	DB_NWORK-1	},
 	{ "arg",	0,			db_arg_variable,
diff --git a/doc/mach.texi b/doc/mach.texi
index b2357b81..913e8bbd 100644
--- a/doc/mach.texi
+++ b/doc/mach.texi
@@ -7155,6 +7155,11 @@ Task or thread structure address.  @var{xx} and @var{yy} are task and
 thread identification numbers printed by a @code{show all threads}
 command respectively.  This variable is read only.
 
+@item map@var{xx}
+VM map structure address.  @var{xx} is a task identification number
+printed by a @code{show all tasks} command.  This variable is read
+only.
+
 @item thread
 The default target thread.  The value is used when @code{t} option is
 specified without explicit thread structure address parameter in command
-- 
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