From efa3b46cdf271628589bde513984e5f5da7458e7 Mon Sep 17 00:00:00 2001
From: Russell Bryant <russell@russellbryant.com>
Date: Thu, 13 Mar 2008 21:38:16 +0000
Subject: [PATCH] Fix another issue that was causing crashes in chanspy.  This
 introduces a new datastore callback, called chan_fixup().  The concept is
 exactly like the fixup callback that is used in the channel technology
 interface.  This callback gets called when the owning channel changes due to
 a masquerade.  Before this was introduced, if a masquerade happened on a
 channel being spyed on, the channel pointer in the datastore became invalid.

(closes issue #12187)
(reported by, and lots of testing from atis)
(props to file for the help with ideas)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@108583 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
 apps/app_chanspy.c         | 10 ++++++++++
 include/asterisk/channel.h | 15 +++++++++++++++
 main/channel.c             |  8 +++++++-
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/apps/app_chanspy.c b/apps/app_chanspy.c
index f2951c3d59..41e658037a 100644
--- a/apps/app_chanspy.c
+++ b/apps/app_chanspy.c
@@ -390,9 +390,19 @@ static void chanspy_ds_destroy(void *data)
 	ast_mutex_unlock(&chanspy_ds->lock);
 }
 
+static void chanspy_ds_chan_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
+{
+	struct chanspy_ds *chanspy_ds = data;
+	
+	ast_mutex_lock(&chanspy_ds->lock);
+	chanspy_ds->chan = new_chan;
+	ast_mutex_unlock(&chanspy_ds->lock);
+}
+
 static const struct ast_datastore_info chanspy_ds_info = {
 	.type = "chanspy",
 	.destroy = chanspy_ds_destroy,
+	.chan_fixup = chanspy_ds_chan_fixup,
 };
 
 static struct chanspy_ds *chanspy_ds_free(struct chanspy_ds *chanspy_ds)
diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index 429308ee06..1172274f78 100644
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -154,6 +154,21 @@ struct ast_datastore_info {
 	const char *type;		/*!< Type of data store */
 	void *(*duplicate)(void *data); /*!< Duplicate item data (used for inheritance) */
 	void (*destroy)(void *data);	/*!< Destroy function */
+	/*!
+	 * \brief Fix up channel references
+	 *
+	 * \arg data The datastore data
+	 * \arg old_chan The old channel owning the datastore
+	 * \arg new_chan The new channel owning the datastore
+	 *
+	 * This is exactly like the fixup callback of the channel technology interface.
+	 * It allows a datastore to fix any pointers it saved to the owning channel
+	 * in case that the owning channel has changed.  Generally, this would happen
+	 * when the datastore is set to be inherited, and a masquerade occurs.
+	 *
+	 * \return nothing.
+	 */
+	void (*chan_fixup)(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
 };
 
 /*! \brief Structure for a channel data store */
diff --git a/main/channel.c b/main/channel.c
index 198e9faf73..bef5602436 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -3494,8 +3494,14 @@ int ast_do_masquerade(struct ast_channel *original)
 
 	ast_app_group_update(clone, original);
 	/* Move data stores over */
-	if (AST_LIST_FIRST(&clone->datastores))
+	if (AST_LIST_FIRST(&clone->datastores)) {
+		struct ast_datastore *ds;
 		AST_LIST_APPEND_LIST(&original->datastores, &clone->datastores, entry);
+		AST_LIST_TRAVERSE(&original->datastores, ds, entry) {
+			if (ds->info->chan_fixup)
+				ds->info->chan_fixup(ds->data, clone, original);
+		}
+	}
 
 	clone_variables(original, clone);
 	/* Presense of ADSI capable CPE follows clone */