From a42bf8cc9250f875f6d26ca7cd2d81e2ea8821d8 Mon Sep 17 00:00:00 2001
From: Richard Mudgett <rmudgett@digium.com>
Date: Wed, 25 May 2011 16:50:38 +0000
Subject: Merged revisions 320796 via svnmerge from
 https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r320796 | rmudgett | 2011-05-25 11:23:11 -0500 (Wed, 25 May 2011) | 17 lines

  Give zombies a safe channel driver to use.

  Recent crashes from zombie channels suggests that they need a safe home to
  goto.  When a masquerade happens, the physical part of the zombie channel
  is hungup.  The hangup normally sets the channel private pointer to NULL.
  If someone then blindly does a callback to the channel driver, a crash is
  likely because the private pointer is NULL.

  The masquerade now sets the channel technology of zombie channels to the
  kill channel driver.

  Related to the following issues:
  (issue #19116)
  (issue #19310)

  Review: https://reviewboard.asterisk.org/r/1224/
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@320820 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
 main/features.c | 53 +++++------------------------------------------------
 1 file changed, 5 insertions(+), 48 deletions(-)

(limited to 'main/features.c')

diff --git a/main/features.c b/main/features.c
index 1bb86fc30..e8e9164d3 100644
--- a/main/features.c
+++ b/main/features.c
@@ -477,59 +477,16 @@ struct ast_dial_features {
 	int is_caller;
 };
 
-#if defined(ATXFER_NULL_TECH)
-static struct ast_frame *null_read(struct ast_channel *chan)
-{
-	/* Hangup channel. */
-	return NULL;
-}
-
-static struct ast_frame *null_exception(struct ast_channel *chan)
-{
-	/* Hangup channel. */
-	return NULL;
-}
-
-static int null_write(struct ast_channel *chan, struct ast_frame *frame)
-{
-	/* Hangup channel. */
-	return -1;
-}
-
-static int null_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
-{
-	/* No problem fixing up the channel. */
-	return 0;
-}
-
-static int null_hangup(struct ast_channel *chan)
-{
-	chan->tech_pvt = NULL;
-	return 0;
-}
-
-static const struct ast_channel_tech null_tech = {
-	.type = "NULL",
-	.description = "NULL channel driver for atxfer",
-	.capabilities = -1,
-	.read = null_read,
-	.exception = null_exception,
-	.write = null_write,
-	.fixup = null_fixup,
-	.hangup = null_hangup,
-};
-#endif	/* defined(ATXFER_NULL_TECH) */
-
 #if defined(ATXFER_NULL_TECH)
 /*!
  * \internal
- * \brief Set the channel technology to the NULL technology.
+ * \brief Set the channel technology to the kill technology.
  *
  * \param chan Channel to change technology.
  *
  * \return Nothing
  */
-static void set_null_chan_tech(struct ast_channel *chan)
+static void set_kill_chan_tech(struct ast_channel *chan)
 {
 	int idx;
 
@@ -546,8 +503,8 @@ static void set_null_chan_tech(struct ast_channel *chan)
 		chan->tech_pvt = NULL;
 	}
 
-	/* Install the NULL technology and wake up anyone waiting on it. */
-	chan->tech = &null_tech;
+	/* Install the kill technology and wake up anyone waiting on it. */
+	chan->tech = &ast_kill_tech;
 	for (idx = 0; idx < AST_MAX_FDS; ++idx) {
 		switch (idx) {
 		case AST_ALERT_FD:
@@ -3146,7 +3103,7 @@ static struct ast_channel *feature_request_and_dial(struct ast_channel *caller,
 				 * Get rid of caller's physical technology so it is free for
 				 * other calls.
 				 */
-				set_null_chan_tech(caller);
+				set_kill_chan_tech(caller);
 #endif	/* defined(ATXFER_NULL_TECH) */
 			} else {
 				/* caller is not hungup so monitor it. */
-- 
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