Convert the ast_channel data structure over to the astobj2 framework.

There is a lot that could be said about this, but the patch is a big 
improvement for performance, stability, code maintainability, 
and ease of future code development.

The channel list is no longer an unsorted linked list.  The main container 
for channels is an astobj2 hash table.  All of the code related to searching 
for channels or iterating active channels has been rewritten.  Let n be 
the number of active channels.  Iterating the channel list has gone from 
O(n^2) to O(n).  Searching for a channel by name went from O(n) to O(1).  
Searching for a channel by extension is still O(n), but uses a new method 
for doing so, which is more efficient.

The ast_channel object is now a reference counted object.  The benefits 
here are plentiful.  Some benefits directly related to issues in the 
previous code include:

1) When threads other than the channel thread owning a channel wanted 
   access to a channel, it had to hold the lock on it to ensure that it didn't 
   go away.  This is no longer a requirement.  Holding a reference is 
   sufficient.

2) There are places that now require less dealing with channel locks.

3) There are places where channel locks are held for much shorter periods 
   of time.

4) There are places where dealing with more than one channel at a time becomes 
   _MUCH_ easier.  ChanSpy is a great example of this.  Writing code in the 
   future that deals with multiple channels will be much easier.

Some additional information regarding channel locking and reference count 
handling can be found in channel.h, where a new section has been added that 
discusses some of the rules associated with it.

Mark Michelson also assisted with the development of this patch.  He did the 
conversion of ChanSpy and introduced a new API, ast_autochan, which makes it 
much easier to deal with holding on to a channel pointer for an extended period 
of time and having it get automatically updated if the channel gets masqueraded.
Mark was also a huge help in the code review process.

Thanks to David Vossel for his assistance with this branch, as well.  David 
did the conversion of the DAHDIScan application by making it become a wrapper 
for ChanSpy internally.

The changes come from the svn/asterisk/team/russell/ast_channel_ao2 branch.

Review: http://reviewboard.digium.com/r/203/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@190423 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 240 insertions, 210 deletions

diff --git a/apps/app_chanspy.c b/apps/app_chanspy.c
index 9d087c4d1..07eac74a2 100644
--- a/apps/app_chanspy.c
+++ b/apps/app_chanspy.c
@@ -50,6 +50,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/module.h"
 #include "asterisk/lock.h"
 #include "asterisk/options.h"
+#include "asterisk/autochan.h"
 
 #define AST_NAME_STRLEN 256
 #define NUM_SPYGROUPS 128
@@ -141,6 +142,16 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 						name of the last channel that was spied on will be stored
 						in the <variable>SPY_CHANNEL</variable> variable.</para>
 					</option>
+					<option name="x">
+						<argument name="digit" required="true">
+							<para>Specify a DTMF digit that can be used to exit the application.</para>
+						</argument>
+					</option>
+					<option name="c">
+						<argument name="digit" required="true">
+							<para>Specify a DTMF digit that can be used to spy on the next available channel.</para>
+						</argument>
+					</option>
 					<option name="e">
 						<argument name="ext" required="true" />
 						<para>Enable <emphasis>enforced</emphasis> mode, so the spying channel can
@@ -262,6 +273,16 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 						name of the last channel that was spied on will be stored
 						in the <variable>SPY_CHANNEL</variable> variable.</para>
 					</option>
+					<option name="x">
+						<argument name="digit" required="true">
+							<para>Specify a DTMF digit that can be used to exit the application.</para>
+						</argument>
+					</option>
+					<option name="c">
+						<argument name="digit" required="true">
+							<para>Specify a DTMF digit that can be used to spy on the next available channel.</para>
+						</argument>
+					</option>
 					<option name="e">
 						<argument name="ext" required="true" />
 						<para>Enable <emphasis>enforced</emphasis> mode, so the spying channel can
@@ -287,12 +308,29 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 			<ref type="application">ChanSpy</ref>
 		</see-also>
 	</application>
-
+	
+	<application name="DAHDIScan" language="en_US">
+		<synopsis>
+			Scan DAHDI channels to monitor calls.
+		</synopsis>
+		<syntax>
+			<parameter name="group">
+				<para>Limit scanning to a channel <replaceable>group</replaceable> by setting this option.</para>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Allows a call center manager to monitor DAHDI channels in a
+			convenient way.  Use <literal>#</literal> to select the next channel and use <literal>*</literal> to exit.</para>
+		</description>
+	</application>
  ***/
+
 static const char *app_chan = "ChanSpy";
 
 static const char *app_ext = "ExtenSpy";
 
+static const char *app_dahdiscan = "DAHDIScan";
+
 enum {
 	OPTION_QUIET             = (1 << 0),    /* Quiet, no announcement */
 	OPTION_BRIDGED           = (1 << 1),    /* Only look at bridged calls */
@@ -307,7 +345,10 @@ enum {
 	OPTION_NOTECH            = (1 << 10),   /* Skip technology name playback */
 	OPTION_BARGE             = (1 << 11),   /* Barge mode (whisper to both channels) */
 	OPTION_NAME              = (1 << 12),   /* Say the name of the person on whom we will spy */
-	OPTION_DTMF_SWITCH_MODES = (1 << 13),   /*Allow numeric DTMF to switch between chanspy modes */
+	OPTION_DTMF_SWITCH_MODES = (1 << 13),   /* Allow numeric DTMF to switch between chanspy modes */
+	OPTION_DTMF_EXIT         = (1 << 14),	/* Set DTMF to exit, added for DAHDIScan integration */
+	OPTION_DTMF_CYCLE        = (1 << 15),	/* Custom DTMF for cycling next avaliable channel, (default is '*') */
+	OPTION_DAHDI_SCAN        = (1 << 16),	/* Scan groups in DAHDIScan mode */
 } chanspy_opt_flags;
 
 enum {
@@ -316,6 +357,8 @@ enum {
 	OPT_ARG_RECORD,
 	OPT_ARG_ENFORCED,
 	OPT_ARG_NAME,
+	OPT_ARG_EXIT,
+	OPT_ARG_CYCLE,
 	OPT_ARG_ARRAY_SIZE,
 } chanspy_opt_args;
 
@@ -334,10 +377,10 @@ AST_APP_OPTIONS(spy_opts, {
 	AST_APP_OPTION('s', OPTION_NOTECH),
 	AST_APP_OPTION_ARG('n', OPTION_NAME, OPT_ARG_NAME),
 	AST_APP_OPTION('d', OPTION_DTMF_SWITCH_MODES),
+	AST_APP_OPTION_ARG('x', OPTION_DTMF_EXIT, OPT_ARG_EXIT),
+	AST_APP_OPTION_ARG('c', OPTION_DTMF_CYCLE, OPT_ARG_CYCLE),
 });
 
-static int next_unique_id_to_use = 0;
-
 struct chanspy_translation_helper {
 	/* spy data */
 	struct ast_audiohook spy_audiohook;
@@ -347,6 +390,12 @@ struct chanspy_translation_helper {
 	int volfactor;
 };
 
+struct spy_dtmf_options {
+	char exit;
+	char cycle;
+	char volume;
+};
+
 static void *spy_alloc(struct ast_channel *chan, void *data)
 {
 	/* just store the data pointer in the channel structure */
@@ -399,27 +448,21 @@ static struct ast_generator spygen = {
 	.generate = spy_generate,
 };
 
-static int start_spying(struct ast_channel *chan, const char *spychan_name, struct ast_audiohook *audiohook)
+static int start_spying(struct ast_autochan *autochan, const char *spychan_name, struct ast_audiohook *audiohook)
 {
 	int res = 0;
 	struct ast_channel *peer = NULL;
 
-	ast_log(LOG_NOTICE, "Attaching %s to %s\n", spychan_name, chan->name);
+	ast_log(LOG_NOTICE, "Attaching %s to %s\n", spychan_name, autochan->chan->name);
 
-	res = ast_audiohook_attach(chan, audiohook);
+	res = ast_audiohook_attach(autochan->chan, audiohook);
 
-	if (!res && ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan))) { 
+	if (!res && ast_test_flag(autochan->chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(autochan->chan))) {
 		ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);
 	}
 	return res;
 }
 
-struct chanspy_ds {
-	struct ast_channel *chan;
-	char unique_id[20];
-	ast_mutex_t lock;
-};
-
 static void change_spy_mode(const char digit, struct ast_flags *flags)
 {
 	if (digit == '4') {
@@ -434,8 +477,9 @@ static void change_spy_mode(const char digit, struct ast_flags *flags)
 	}
 }
 
-static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chanspy_ds, 
-	int *volfactor, int fd, struct ast_flags *flags, char *exitcontext) 
+static int channel_spy(struct ast_channel *chan, struct ast_autochan *spyee_autochan,
+	int *volfactor, int fd, struct spy_dtmf_options *user_options, struct ast_flags *flags,
+	char *exitcontext)
 {
 	struct chanspy_translation_helper csth;
 	int running = 0, res, x = 0;
@@ -443,32 +487,22 @@ static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chansp
 	char *name;
 	struct ast_frame *f;
 	struct ast_silence_generator *silgen = NULL;
-	struct ast_channel *spyee = NULL, *spyee_bridge = NULL;
+	struct ast_autochan *spyee_bridge_autochan = NULL;
 	const char *spyer_name;
 
 	ast_channel_lock(chan);
 	spyer_name = ast_strdupa(chan->name);
 	ast_channel_unlock(chan);
 
-	ast_mutex_lock(&spyee_chanspy_ds->lock);
-	if (spyee_chanspy_ds->chan) {
-		spyee = spyee_chanspy_ds->chan;
-		ast_channel_lock(spyee);
-	}
-	ast_mutex_unlock(&spyee_chanspy_ds->lock);
-
-	if (!spyee) {
-		return 0;
-	}
-
 	/* We now hold the channel lock on spyee */
 
-	if (ast_check_hangup(chan) || ast_check_hangup(spyee)) {
-		ast_channel_unlock(spyee);
+	if (ast_check_hangup(chan) || ast_check_hangup(spyee_autochan->chan)) {
 		return 0;
 	}
 
-	name = ast_strdupa(spyee->name);
+	ast_channel_lock(spyee_autochan->chan);
+	name = ast_strdupa(spyee_autochan->chan->name);
+	ast_channel_unlock(spyee_autochan->chan);
 
 	ast_verb(2, "Spying on channel %s\n", name);
 	manager_event(EVENT_FLAG_CALL, "ChanSpyStart",
@@ -480,26 +514,23 @@ static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chansp
 
 	ast_audiohook_init(&csth.spy_audiohook, AST_AUDIOHOOK_TYPE_SPY, "ChanSpy");
 
-	if (start_spying(spyee, spyer_name, &csth.spy_audiohook)) {
+	if (start_spying(spyee_autochan, spyer_name, &csth.spy_audiohook)) {
 		ast_audiohook_destroy(&csth.spy_audiohook);
-		ast_channel_unlock(spyee);
 		return 0;
 	}
 
- 	ast_audiohook_init(&csth.whisper_audiohook, AST_AUDIOHOOK_TYPE_WHISPER, "ChanSpy");
+	ast_audiohook_init(&csth.whisper_audiohook, AST_AUDIOHOOK_TYPE_WHISPER, "ChanSpy");
 	ast_audiohook_init(&csth.bridge_whisper_audiohook, AST_AUDIOHOOK_TYPE_WHISPER, "Chanspy");
-  	if (start_spying(spyee, spyer_name, &csth.whisper_audiohook)) {
-		ast_log(LOG_WARNING, "Unable to attach whisper audiohook to spyee %s. Whisper mode disabled!\n", spyee->name);
+	if (start_spying(spyee_autochan, spyer_name, &csth.whisper_audiohook)) {
+		ast_log(LOG_WARNING, "Unable to attach whisper audiohook to spyee %s. Whisper mode disabled!\n", name);
 	}
-	if ((spyee_bridge = ast_bridged_channel(spyee))) {
-		ast_channel_lock(spyee_bridge);
-		if (start_spying(spyee_bridge, spyer_name, &csth.bridge_whisper_audiohook)) {
-			ast_log(LOG_WARNING, "Unable to attach barge audiohook on spyee %s. Barge mode disabled!\n", spyee->name);
+	if ((spyee_bridge_autochan = ast_autochan_setup(ast_bridged_channel(spyee_autochan->chan)))) {
+		ast_channel_lock(spyee_bridge_autochan->chan);
+		if (start_spying(spyee_bridge_autochan, spyer_name, &csth.bridge_whisper_audiohook)) {
+			ast_log(LOG_WARNING, "Unable to attach barge audiohook on spyee %s. Barge mode disabled!\n", name);
 		}
-		ast_channel_unlock(spyee_bridge);
+		ast_channel_unlock(spyee_bridge_autochan->chan);
 	}
-	ast_channel_unlock(spyee);
-	spyee = NULL;
 
 	ast_channel_lock(chan);
 	ast_set_flag(chan, AST_FLAG_END_DTMF_ONLY);
@@ -589,10 +620,13 @@ static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chansp
 			}
 		}
 
-		if (res == '*') {
+		if (res == user_options->cycle) {
 			running = 0;
 			break;
-		} else if (res == '#') {
+		} else if (res == user_options->exit) {
+			running = -2;
+			break;
+		} else if (res == user_options->volume) {
 			if (!ast_strlen_zero(inp)) {
 				running = atoi(inp);
 				break;
@@ -632,128 +666,45 @@ static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chansp
 	ast_audiohook_detach(&csth.spy_audiohook);
 	ast_audiohook_unlock(&csth.spy_audiohook);
 	ast_audiohook_destroy(&csth.spy_audiohook);
-	
+
+	if (spyee_bridge_autochan) {
+		ast_autochan_destroy(spyee_bridge_autochan);
+	}
+
 	ast_verb(2, "Done Spying on channel %s\n", name);
 	manager_event(EVENT_FLAG_CALL, "ChanSpyStop", "SpyeeChannel: %s\r\n", name);
 
 	return running;
 }
 
-/*!
- * \note This relies on the embedded lock to be recursive, as it may be called
- * due to a call to chanspy_ds_free with the lock held there.
- */
-static void chanspy_ds_destroy(void *data)
-{
-	struct chanspy_ds *chanspy_ds = data;
-
-	/* Setting chan to be NULL is an atomic operation, but we don't want this
-	 * value to change while this lock is held.  The lock is held elsewhere
-	 * while it performs non-atomic operations with this channel pointer */
-
-	ast_mutex_lock(&chanspy_ds->lock);
-	chanspy_ds->chan = NULL;
-	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)
-{
-	if (!chanspy_ds)
-		return NULL;
-
-	ast_mutex_lock(&chanspy_ds->lock);
-	if (chanspy_ds->chan) {
-		struct ast_datastore *datastore;
-		struct ast_channel *chan;
-
-		chan = chanspy_ds->chan;
-
-		ast_channel_lock(chan);
-		if ((datastore = ast_channel_datastore_find(chan, &chanspy_ds_info, chanspy_ds->unique_id))) {
-			ast_channel_datastore_remove(chan, datastore);
-			/* chanspy_ds->chan is NULL after this call */
-			chanspy_ds_destroy(datastore->data);
-			datastore->data = NULL;
-			ast_datastore_free(datastore);
-		}
-		ast_channel_unlock(chan);
-	}
-	ast_mutex_unlock(&chanspy_ds->lock);
-
-	return NULL;
-}
-
-/*! \note Returns the channel in the chanspy_ds locked as well as the chanspy_ds locked */
-static struct chanspy_ds *setup_chanspy_ds(struct ast_channel *chan, struct chanspy_ds *chanspy_ds)
+static struct ast_autochan *next_channel(struct ast_channel_iterator *iter,
+		struct ast_autochan *autochan, struct ast_channel *chan)
 {
-	struct ast_datastore *datastore = NULL;
-
-	ast_mutex_lock(&chanspy_ds->lock);
+	struct ast_channel *next;
+	const size_t pseudo_len = strlen("DAHDI/pseudo");
 
-	if (!(datastore = ast_datastore_alloc(&chanspy_ds_info, chanspy_ds->unique_id))) {
-		ast_mutex_unlock(&chanspy_ds->lock);
-		chanspy_ds = chanspy_ds_free(chanspy_ds);
-		ast_channel_unlock(chan);
+	if (!iter) {
 		return NULL;
 	}
-	
-	chanspy_ds->chan = chan;
-	datastore->data = chanspy_ds;
-	ast_channel_datastore_add(chan, datastore);
-
-	return chanspy_ds;
-}
-
-static struct chanspy_ds *next_channel(struct ast_channel *chan,
-	const struct ast_channel *last, const char *spec,
-	const char *exten, const char *context, struct chanspy_ds *chanspy_ds)
-{
-	struct ast_channel *next;
-	const size_t pseudo_len = strlen("DAHDI/pseudo");
 
 redo:
-	if (!ast_strlen_zero(spec))
-		next = ast_walk_channel_by_name_prefix_locked(last, spec, strlen(spec));
-	else if (!ast_strlen_zero(exten))
-		next = ast_walk_channel_by_exten_locked(last, exten, context);
-	else
-		next = ast_channel_walk_locked(last);
-
-	if (!next)
+	if (!(next = ast_channel_iterator_next(iter))) {
 		return NULL;
+	}
 
 	if (!strncmp(next->name, "DAHDI/pseudo", pseudo_len)) {
-		last = next;
-		ast_channel_unlock(next);
 		goto redo;
 	} else if (next == chan) {
-		last = next;
-		ast_channel_unlock(next);
 		goto redo;
 	}
 
-	return setup_chanspy_ds(next, chanspy_ds);
+	return ast_autochan_setup(next);
 }
 
 static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
-	int volfactor, const int fd, const char *mygroup, const char *myenforced,
-	const char *spec, const char *exten, const char *context, const char *mailbox,
-	const char *name_context)
+	int volfactor, const int fd, struct spy_dtmf_options *user_options,
+	const char *mygroup, const char *myenforced, const char *spec, const char *exten,
+	const char *context, const char *mailbox, const char *name_context)
 {
 	char nameprefix[AST_NAME_STRLEN];
 	char peer_name[AST_NAME_STRLEN + 5];
@@ -764,7 +715,7 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 	char *ptr;
 	int num;
 	int num_spyed_upon = 1;
-	struct chanspy_ds chanspy_ds = { 0, };
+	struct ast_channel_iterator *iter = NULL;
 
 	if (ast_test_flag(flags, OPTION_EXIT)) {
 		const char *c;
@@ -779,10 +730,6 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 		ast_channel_unlock(chan);
 	}
 
-	ast_mutex_init(&chanspy_ds.lock);
-
-	snprintf(chanspy_ds.unique_id, sizeof(chanspy_ds.unique_id), "%d", ast_atomic_fetchadd_int(&next_unique_id_to_use, +1));
-
 	if (chan->_state != AST_STATE_UP)
 		ast_answer(chan);
 
@@ -791,8 +738,8 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 	waitms = 100;
 
 	for (;;) {
-		struct chanspy_ds *peer_chanspy_ds = NULL, *next_chanspy_ds = NULL;
-		struct ast_channel *prev = NULL, *peer = NULL;
+		struct ast_autochan *autochan = NULL, *next_autochan = NULL;
+		struct ast_channel *prev = NULL;
 
 		if (!ast_test_flag(flags, OPTION_QUIET) && num_spyed_upon) {
 			res = ast_streamfile(chan, "beep", chan->language);
@@ -813,6 +760,19 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 			}
 		}
 
+		/* Set up the iterator we'll be using during this call */
+		if (!ast_strlen_zero(spec)) {
+			iter = ast_channel_iterator_by_name_new(0, spec, strlen(spec));
+		} else if (!ast_strlen_zero(exten)) {
+			iter = ast_channel_iterator_by_exten_new(0, exten, context);
+		} else {
+			iter = ast_channel_iterator_all_new(0);
+		}
+
+		if (!iter) {
+			return -1;
+		}
+
 		res = ast_waitfordigit(chan, waitms);
 		if (res < 0) {
 			ast_clear_flag(chan, AST_FLAG_SPYING);
@@ -832,38 +792,30 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 		waitms = 100;
 		num_spyed_upon = 0;
 
-		for (peer_chanspy_ds = next_channel(chan, prev, spec, exten, context, &chanspy_ds);
-		     peer_chanspy_ds;
-			 chanspy_ds_free(peer_chanspy_ds), prev = peer,
-		     peer_chanspy_ds = next_chanspy_ds ? next_chanspy_ds : 
-			 	next_channel(chan, prev, spec, exten, context, &chanspy_ds), next_chanspy_ds = NULL) {
+		for (autochan = next_channel(iter, autochan, chan);
+		     autochan;
+			 prev = autochan->chan, ast_autochan_destroy(autochan),
+		     autochan = next_autochan ? next_autochan : 
+				next_channel(iter, autochan, chan), next_autochan = NULL) {
 			int igrp = !mygroup;
 			int ienf = !myenforced;
 			char *s;
 
-			peer = peer_chanspy_ds->chan;
-
-			ast_mutex_unlock(&peer_chanspy_ds->lock);
-
-			if (peer == prev) {
-				ast_channel_unlock(peer);
-				chanspy_ds_free(peer_chanspy_ds);
+			if (autochan->chan == prev) {
+				ast_autochan_destroy(autochan);
 				break;
 			}
 
 			if (ast_check_hangup(chan)) {
-				ast_channel_unlock(peer);
-				chanspy_ds_free(peer_chanspy_ds);
+				ast_autochan_destroy(autochan);
 				break;
 			}
 
-			if (ast_test_flag(flags, OPTION_BRIDGED) && !ast_bridged_channel(peer)) {
-				ast_channel_unlock(peer);
+			if (ast_test_flag(flags, OPTION_BRIDGED) && !ast_bridged_channel(autochan->chan)) {
 				continue;
 			}
 
-			if (ast_check_hangup(peer) || ast_test_flag(peer, AST_FLAG_SPYING)) {
-				ast_channel_unlock(peer);
+			if (ast_check_hangup(autochan->chan) || ast_test_flag(autochan->chan, AST_FLAG_SPYING)) {
 				continue;
 			}
 
@@ -874,14 +826,22 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 				char dup_mygroup[512];
 				char *groups[NUM_SPYGROUPS];
 				char *mygroups[NUM_SPYGROUPS];
-				const char *group;
+				const char *group = NULL;
 				int x;
 				int y;
 				ast_copy_string(dup_mygroup, mygroup, sizeof(dup_mygroup));
 				num_mygroups = ast_app_separate_args(dup_mygroup, ':', mygroups,
 					ARRAY_LEN(mygroups));
 
-				if ((group = pbx_builtin_getvar_helper(peer, "SPYGROUP"))) {
+				/* Before dahdi scan was part of chanspy, it would use the "GROUP" variable 
+				 * rather than "SPYGROUP", this check is done to preserve expected behavior */
+				if (ast_test_flag(flags, OPTION_DAHDI_SCAN)) {
+					group = pbx_builtin_getvar_helper(autochan->chan, "GROUP");
+				} else {
+					group = pbx_builtin_getvar_helper(autochan->chan, "SPYGROUP");
+				}
+
+				if (!ast_strlen_zero(group)) {
 					ast_copy_string(dup_group, group, sizeof(dup_group));
 					num_groups = ast_app_separate_args(dup_group, ':', groups,
 						ARRAY_LEN(groups));
@@ -898,10 +858,8 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 			}
 
 			if (!igrp) {
-				ast_channel_unlock(peer);
 				continue;
 			}
-
 			if (myenforced) {
 				char ext[AST_CHANNEL_NAME + 3];
 				char buffer[512];
@@ -909,7 +867,7 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 
 				snprintf(buffer, sizeof(buffer) - 1, ":%s:", myenforced);
 
-				ast_copy_string(ext + 1, peer->name, sizeof(ext) - 1);
+				ast_copy_string(ext + 1, autochan->chan->name, sizeof(ext) - 1);
 				if ((end = strchr(ext, '-'))) {
 					*end++ = ':';
 					*end = '\0';
@@ -927,18 +885,13 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 			}
 
 			strcpy(peer_name, "spy-");
-			strncat(peer_name, peer->name, AST_NAME_STRLEN - 4 - 1);
+			strncat(peer_name, autochan->chan->name, AST_NAME_STRLEN - 4 - 1);
 			ptr = strchr(peer_name, '/');
 			*ptr++ = '\0';
 			ptr = strsep(&ptr, "-");
 
 			for (s = peer_name; s < ptr; s++)
 				*s = tolower(*s);
-			/* We have to unlock the peer channel here to avoid a deadlock.
-			 * So, when we need to dereference it again, we have to lock the 
-			 * datastore and get the pointer from there to see if the channel 
-			 * is still valid. */
-			ast_channel_unlock(peer);
 
 			if (!ast_test_flag(flags, OPTION_QUIET)) {
 				if (ast_test_flag(flags, OPTION_NAME)) {
@@ -954,7 +907,7 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 								res = ast_waitstream(chan, "");
 							}
 							if (res) {
-								chanspy_ds_free(peer_chanspy_ds);
+								ast_autochan_destroy(autochan);
 								break;
 							}
 						} else {
@@ -966,42 +919,38 @@ static int common_exec(struct ast_channel *chan, struct ast_flags *flags,
 				}
 			}
 
-			res = channel_spy(chan, peer_chanspy_ds, &volfactor, fd, flags, exitcontext);
-			num_spyed_upon++;	
+			res = channel_spy(chan, autochan, &volfactor, fd, user_options, flags, exitcontext);
+			num_spyed_upon++;
 
 			if (res == -1) {
-				chanspy_ds_free(peer_chanspy_ds);
+				ast_autochan_destroy(autochan);
 				goto exit;
 			} else if (res == -2) {
 				res = 0;
-				chanspy_ds_free(peer_chanspy_ds);
+				ast_autochan_destroy(autochan);
 				goto exit;
 			} else if (res > 1 && spec) {
 				struct ast_channel *next;
 
 				snprintf(nameprefix, AST_NAME_STRLEN, "%s/%d", spec, res);
 
-				if ((next = ast_get_channel_by_name_prefix_locked(nameprefix, strlen(nameprefix)))) {
-					peer_chanspy_ds = chanspy_ds_free(peer_chanspy_ds);
-					next_chanspy_ds = setup_chanspy_ds(next, &chanspy_ds);
+				if ((next = ast_channel_get_by_name_prefix(nameprefix, strlen(nameprefix)))) {
+					next_autochan = ast_autochan_setup(next);
+					next = ast_channel_unref(next);
 				} else {
 					/* stay on this channel, if it is still valid */
-
-					ast_mutex_lock(&peer_chanspy_ds->lock);
-					if (peer_chanspy_ds->chan) {
-						ast_channel_lock(peer_chanspy_ds->chan);
-						next_chanspy_ds = peer_chanspy_ds;
-						peer_chanspy_ds = NULL;
+					if (!ast_check_hangup(autochan->chan)) {
+						next_autochan = ast_autochan_setup(autochan->chan);
 					} else {
 						/* the channel is gone */
-						ast_mutex_unlock(&peer_chanspy_ds->lock);
-						next_chanspy_ds = NULL;
+						next_autochan = NULL;
 					}
 				}
-
-				peer = NULL;
 			}
 		}
+
+		iter = ast_channel_iterator_destroy(iter);
+
 		if (res == -1 || ast_check_hangup(chan))
 			break;
 	}
@@ -1011,10 +960,6 @@ exit:
 
 	ast_channel_setoption(chan, AST_OPTION_TXGAIN, &zero_volume, sizeof(zero_volume), 0);
 
-	ast_mutex_lock(&chanspy_ds.lock);
-	ast_mutex_unlock(&chanspy_ds.lock);
-	ast_mutex_destroy(&chanspy_ds.lock);
-
 	return res;
 }
 
@@ -1025,6 +970,11 @@ static int chanspy_exec(struct ast_channel *chan, void *data)
 	char *recbase = NULL;
 	int fd = 0;
 	struct ast_flags flags;
+	struct spy_dtmf_options user_options = {
+		.cycle = '*',
+		.volume = '#',
+		.exit = '\0',
+	};
 	int oldwf = 0;
 	int volfactor = 0;
 	int res;
@@ -1043,6 +993,7 @@ static int chanspy_exec(struct ast_channel *chan, void *data)
 		args.spec = NULL;
 
 	if (args.options) {
+		char tmp;
 		ast_app_parse_options(spy_opts, &flags, opts, args.options);
 		if (ast_test_flag(&flags, OPTION_GROUP))
 			mygroup = opts[OPT_ARG_GROUP];
@@ -1051,6 +1002,24 @@ static int chanspy_exec(struct ast_channel *chan, void *data)
 			!(recbase = opts[OPT_ARG_RECORD]))
 			recbase = "chanspy";
 
+		if (ast_test_flag(&flags, OPTION_DTMF_EXIT) && opts[OPT_ARG_EXIT]) {
+			tmp = opts[OPT_ARG_EXIT][0];
+			if (strchr("0123456789*#", tmp) && tmp != '\0') {
+				user_options.exit = tmp;
+			} else {
+				ast_log(LOG_NOTICE, "Argument for option 'x' must be a valid DTMF digit.");
+			}
+		}
+
+		if (ast_test_flag(&flags, OPTION_DTMF_CYCLE) && opts[OPT_ARG_CYCLE]) {
+			tmp = opts[OPT_ARG_CYCLE][0];
+			if (strchr("0123456789*#", tmp) && tmp != '\0') {
+				user_options.cycle = tmp;
+			} else {
+				ast_log(LOG_NOTICE, "Argument for option 'c' must be a valid DTMF digit.");
+			}
+		}
+
 		if (ast_test_flag(&flags, OPTION_VOLUME) && opts[OPT_ARG_VOLUME]) {
 			int vol;
 
@@ -1065,7 +1034,7 @@ static int chanspy_exec(struct ast_channel *chan, void *data)
 
 		if (ast_test_flag(&flags, OPTION_ENFORCED))
 			myenforced = opts[OPT_ARG_ENFORCED];
-		
+
 		if (ast_test_flag(&flags, OPTION_NAME)) {
 			if (!ast_strlen_zero(opts[OPT_ARG_NAME])) {
 				char *delimiter;
@@ -1078,10 +1047,9 @@ static int chanspy_exec(struct ast_channel *chan, void *data)
 				}
 			}
 		}
-
-
-	} else
+	} else {
 		ast_clear_flag(&flags, AST_FLAGS_ALL);
+	}
 
 	oldwf = chan->writeformat;
 	if (ast_set_write_format(chan, AST_FORMAT_SLINEAR) < 0) {
@@ -1099,7 +1067,7 @@ static int chanspy_exec(struct ast_channel *chan, void *data)
 		}
 	}
 
-	res = common_exec(chan, &flags, volfactor, fd, mygroup, myenforced, args.spec, NULL, NULL, mailbox, name_context);
+	res = common_exec(chan, &flags, volfactor, fd, &user_options, mygroup, myenforced, args.spec, NULL, NULL, mailbox, name_context);
 
 	if (fd)
 		close(fd);
@@ -1117,6 +1085,11 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 	char *recbase = NULL;
 	int fd = 0;
 	struct ast_flags flags;
+	struct spy_dtmf_options user_options = {
+		.cycle = '*',
+		.volume = '#',
+		.exit = '\0',
+	};
 	int oldwf = 0;
 	int volfactor = 0;
 	int res;
@@ -1141,6 +1114,7 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 
 	if (args.options) {
 		char *opts[OPT_ARG_ARRAY_SIZE];
+		char tmp;
 
 		ast_app_parse_options(spy_opts, &flags, opts, args.options);
 		if (ast_test_flag(&flags, OPTION_GROUP))
@@ -1150,6 +1124,24 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 			!(recbase = opts[OPT_ARG_RECORD]))
 			recbase = "chanspy";
 
+		if (ast_test_flag(&flags, OPTION_DTMF_EXIT) && opts[OPT_ARG_EXIT]) {
+			tmp = opts[OPT_ARG_EXIT][0];
+			if (strchr("0123456789*#", tmp) && tmp != '\0') {
+				user_options.exit = tmp;
+			} else {
+				ast_log(LOG_NOTICE, "Argument for option 'x' must be a valid DTMF digit.");
+			}
+		}
+
+		if (ast_test_flag(&flags, OPTION_DTMF_CYCLE) && opts[OPT_ARG_CYCLE]) {
+			tmp = opts[OPT_ARG_CYCLE][0];
+			if (strchr("0123456789*#", tmp) && tmp != '\0') {
+				user_options.cycle = tmp;
+			} else {
+				ast_log(LOG_NOTICE, "Argument for option 'c' must be a valid DTMF digit.");
+			}
+		}
+
 		if (ast_test_flag(&flags, OPTION_VOLUME) && opts[OPT_ARG_VOLUME]) {
 			int vol;
 
@@ -1162,7 +1154,6 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 		if (ast_test_flag(&flags, OPTION_PRIVATE))
 			ast_set_flag(&flags, OPTION_WHISPER);
 
-		
 		if (ast_test_flag(&flags, OPTION_NAME)) {
 			if (!ast_strlen_zero(opts[OPT_ARG_NAME])) {
 				char *delimiter;
@@ -1176,8 +1167,9 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 			}
 		}
 
-	} else
+	} else {
 		ast_clear_flag(&flags, AST_FLAGS_ALL);
+	}
 
 	oldwf = chan->writeformat;
 	if (ast_set_write_format(chan, AST_FORMAT_SLINEAR) < 0) {
@@ -1196,7 +1188,7 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 	}
 
 
-	res = common_exec(chan, &flags, volfactor, fd, mygroup, NULL, NULL, exten, args.context, mailbox, name_context);
+	res = common_exec(chan, &flags, volfactor, fd, &user_options, mygroup, NULL, NULL, exten, args.context, mailbox, name_context);
 
 	if (fd)
 		close(fd);
@@ -1207,12 +1199,49 @@ static int extenspy_exec(struct ast_channel *chan, void *data)
 	return res;
 }
 
+static int dahdiscan_exec(struct ast_channel *chan, void *data)
+{
+	const char *spec = "DAHDI";
+	struct ast_flags flags;
+	struct spy_dtmf_options user_options = {
+		.cycle = '#',
+		.volume = '\0',
+		.exit = '*',
+	};
+	int oldwf = 0;
+	int res;
+	char *mygroup = NULL;
+
+	ast_clear_flag(&flags, AST_FLAGS_ALL);
+
+	if (!ast_strlen_zero(data)) {
+		mygroup = ast_strdupa(data);
+	}
+	ast_set_flag(&flags, OPTION_DTMF_EXIT);
+	ast_set_flag(&flags, OPTION_DTMF_CYCLE);
+	ast_set_flag(&flags, OPTION_DAHDI_SCAN);
+
+	oldwf = chan->writeformat;
+	if (ast_set_write_format(chan, AST_FORMAT_SLINEAR) < 0) {
+		ast_log(LOG_ERROR, "Could Not Set Write Format.\n");
+		return -1;
+	}
+
+	res = common_exec(chan, &flags, 0, 0, &user_options, mygroup, NULL, spec, NULL, NULL, NULL, NULL);
+
+	if (oldwf && ast_set_write_format(chan, oldwf) < 0)
+		ast_log(LOG_ERROR, "Could Not Set Write Format.\n");
+
+	return res;
+}
+
 static int unload_module(void)
 {
 	int res = 0;
 
 	res |= ast_unregister_application(app_chan);
 	res |= ast_unregister_application(app_ext);
+	res |= ast_unregister_application(app_dahdiscan);
 
 	return res;
 }
@@ -1223,6 +1252,7 @@ static int load_module(void)
 
 	res |= ast_register_application_xml(app_chan, chanspy_exec);
 	res |= ast_register_application_xml(app_ext, extenspy_exec);
+	res |= ast_register_application_xml(app_dahdiscan, dahdiscan_exec);
 
 	return res;
 }