Add support for AVIRT

Leverage the new AVIRT driver for a more secure, more dynamically
configurable loopback sound driver.

To use, replace the file smixer-4a-default.json with
smixer-4a-avirt.json, at /usr/libexec/agl/smixer/etc.
The snd-avirt drivers are installed in AGL by default as of 6.99.2.

The existing snd-aloop configuration is not broken by this change.

Change-Id: I827636656c109a7393ad77997e05069a2462ea46
Signed-off-by: Mark Farrugia <mark.farrugia@fiberdyne.com.au>

1 files changed, 22 insertions, 11 deletions

diff --git a/plugins/alsa/alsa-api-mixer.c b/plugins/alsa/alsa-api-mixer.c
index e892b2f..ebb8c25 100644
--- a/plugins/alsa/alsa-api-mixer.c
+++ b/plugins/alsa/alsa-api-mixer.c
@@ -27,6 +27,9 @@ static struct cds_list_head mixerList;
 
 static void MixerDelete(SoftMixerT * mixer);
 
+// AVIRT: temporary loops JSON
+static json_object *LoopsJ = NULL;
+
 static void MixerExit() {
 	SoftMixerT *mixer, *tmp;
 	printf("%s !\n", __func__);
@@ -575,13 +578,6 @@ STATIC void MixerAttachVerb(afb_req_t request) {
 
 	mixer->transaction = transaction;
 
-    AFB_API_INFO(mixer->api, "%s set LOOPS", __func__);
-
-    if (loopsJ) {
-        error = ApiLoopAttach(mixer, request, uid, loopsJ);
-		if (error) goto fail;
-    }
-    
 	AFB_API_INFO(mixer->api, "%s set PLAYBACKS", __func__);
 
     if (playbacksJ) {
@@ -616,6 +612,16 @@ STATIC void MixerAttachVerb(afb_req_t request) {
         json_object_object_add(responseJ, "zone", resultJ);
     }
 
+    // In AVIRT mode, we require both the loops and streams JSON objects to
+    // construct the loopbacks, so when the loops are set, but the streams
+    // are not, we need to save the loops until the streams are given to us
+    if (streamsJ && (loopsJ || LoopsJ)) {
+        AFB_API_INFO(mixer->api, "%s set LOOPS/AVIRT", __func__);
+        error = ApiLoopAttach(mixer, request, uid,
+                              ((loopsJ) ? loopsJ : LoopsJ), streamsJ);
+        if (error) goto fail_loop;
+    }
+
     AFB_API_INFO(mixer->api, "%s set RAMPS", __func__);
 
     if (rampsJ) {
@@ -657,12 +663,12 @@ fail_ramp:
 	// TODO remove created ramps
 fail_zone:
 	// TODO remove created zone
+fail_loop:
+	// TODO remove created loops
 fail_source:
 	// TODO remove created sources
 fail_sink:
 	// TODO remove created sinks
-fail_loop:
-	// TODO remove created loops
 fail:
 
 	if (mixer->transaction)
@@ -734,9 +740,14 @@ CTLP_CAPI(MixerAttach, source, argsJ, responseJ) {
         if (error) goto OnErrorExit;
     }
 
-    if (loopsJ) {
-        error = ApiLoopAttach(mixer, NULL, uid, loopsJ);
+    // In AVIRT mode, we require both the loops and streams JSON objects to
+    // construct the loopbacks, so when the loops are set, but the streams
+    // are not, we need to save the loops until the streams are given to us
+    if (loopsJ && streamsJ) {
+        error = ApiLoopAttach(mixer, NULL, uid, loopsJ, streamsJ);
         if (error) goto OnErrorExit;
+    } else {
+      LoopsJ = loopsJ;
     }
 
     if (zonesJ) {