Rework ALSA card control events functions

Rework ALSA card control events subscription and handling to:
- Clean unnecessary part of codes.
- Increase reliability of ALSA control events polling callback.

Bug-AGL: SPEC-2749

Change-Id: I75dc90483254b1befdf83968c9032ec877c1d895
Signed-off-by: Jonathan Aillet <jonathan.aillet@iot.bzh>

1 files changed, 84 insertions, 66 deletions

diff --git a/alsa-binding/Alsa-RegEvt.c b/alsa-binding/Alsa-RegEvt.c
index 36bb590..c9ac5f1 100644
--- a/alsa-binding/Alsa-RegEvt.c
+++ b/alsa-binding/Alsa-RegEvt.c
@@ -32,15 +32,17 @@ typedef struct {
     snd_ctl_t *ctlDev;
     int mode;
     afb_event_t afbevt;
-} evtHandleT;
+} ctrlEvtHandleT;
 
 typedef struct {
-    int ucount;
-    int cardId;
-    evtHandleT *evtHandle;
+    ctrlEvtHandleT *evtHandle;
 } sndHandleT;
 
 typedef struct {
+    sndHandleT sndHandles[MAX_SND_CARD];
+} sndCardsT;
+
+typedef struct {
     int  cardid;
     char *devid;
     char *apiprefix;
@@ -86,11 +88,12 @@ OnErrorExit:
     return NULL;
 }
 
-// This routine is called when ALSA event are fired
 
+// This routine is called when ALSA control events are fired
 STATIC int sndCtlEventCB(sd_event_source* src, int fd, uint32_t revents, void* userData) {
     int err, ctlNumid;
-    evtHandleT *evtHandle = (evtHandleT*) userData;
+    sndHandleT *sndHandle = (sndHandleT *) userData;
+    ctrlEvtHandleT *evtHandle = (ctrlEvtHandleT*) sndHandle->evtHandle;
     snd_ctl_event_t *eventId;
     json_object *ctlEventJ;
     unsigned int mask;
@@ -104,7 +107,11 @@ STATIC int sndCtlEventCB(sd_event_source* src, int fd, uint32_t revents, void* u
     if ((revents & EPOLLERR) != 0) {
         AFB_ERROR("An error has been send by event loop polling, prevent new errors to be fired by deleting event src");
         sd_event_source_unref(src);
-        return -1;
+        afb_event_unref(sndHandle->evtHandle->afbevt);
+        snd_ctl_close(sndHandle->evtHandle->ctlDev);
+        free(sndHandle->evtHandle);
+        sndHandle->evtHandle = NULL;
+        goto OnErrorExit;
     }
 
     if ((revents & EPOLLHUP) != 0) {
@@ -113,7 +120,6 @@ STATIC int sndCtlEventCB(sd_event_source* src, int fd, uint32_t revents, void* u
     }
 
     if ((revents & EPOLLIN) != 0) {
-
         // initialise event structure on stack
         snd_ctl_event_alloca(&eventId);
         snd_ctl_elem_id_alloca(&elemId);
@@ -155,7 +161,6 @@ STATIC int sndCtlEventCB(sd_event_source* src, int fd, uint32_t revents, void* u
             json_object_object_add(ctlEventJ, "sub", json_object_new_int(subdev));
         }
 
-
         AFB_DEBUG("sndCtlEventCB=%s", json_object_get_string(ctlEventJ));
         afb_event_push(evtHandle->afbevt, ctlEventJ);
     }
@@ -164,105 +169,118 @@ ExitOnSucess:
     return 0;
 
 OnErrorExit:
-    AFB_WARNING("sndCtlEventCB: ignored unsupported event type");
-    return (0);
+    AFB_WARNING("sndCtlEventCB: Error detected");
+    return -1;
 }
 
-// Subscribe to every Alsa CtlEvent send by a given board
 
-PUBLIC void alsaEvtSubcribe(afb_req_t request) {
-    static sndHandleT sndHandles[MAX_SND_CARD];
-    evtHandleT *evtHandle = NULL;
+// Subscribe to every Alsa CtlEvent send by a given board
+STATIC afb_event_t alsaEvtSubscribeAlsaControlEvent(afb_req_t request, sndCardsT *sndCards, queryValuesT *queryValues) {
+    sndHandleT *currentSndHandle = NULL;
     snd_ctl_t *ctlDev = NULL;
-    int err, idx, cardId, idxFree = -1;
+    int err, cardId;
     snd_ctl_card_info_t *cardinfo;
-    queryValuesT queryValues;
-
-    json_object *queryJ = alsaCheckQuery(request, &queryValues);
-    if (!queryJ) goto OnErrorExit;
 
     // open control interface for devid
-    err = snd_ctl_open(&ctlDev, queryValues.devid, SND_CTL_READONLY);
+    err = snd_ctl_open(&ctlDev, queryValues->devid, SND_CTL_READONLY);
     if (err < 0) {
-        afb_req_fail_f(request, "devid-unknown", "SndCard devid=%s Not Found err=%s", queryValues.devid, snd_strerror(err));
+        afb_req_fail_f(request, "devid-unknown", "SndCard devid=%s Not Found err=%s", queryValues->devid, snd_strerror(err));
         goto OnErrorExit;
     }
 
     snd_ctl_card_info_alloca(&cardinfo);
-    if ((err = snd_ctl_card_info(ctlDev, cardinfo)) < 0) {
-        afb_req_fail_f(request, "devid-invalid", "SndCard devid=%s Not Found err=%s", queryValues.devid, snd_strerror(err));
+    err = snd_ctl_card_info(ctlDev, cardinfo);
+    if (err < 0) {
+        afb_req_fail_f(request, "devid-invalid", "SndCard devid=%s Not Found err=%s", queryValues->devid, snd_strerror(err));
         goto OnErrorExit;
     }
 
     cardId = snd_ctl_card_info_get_card(cardinfo);
 
-    // search for an existing subscription and mark 1st free slot
-    for (idx = 0; idx < MAX_SND_CARD; idx++) {
-        if (sndHandles[idx].ucount > 0 && cardId == sndHandles[idx].cardId) {
-            evtHandle = sndHandles[idx].evtHandle;
-            break;
-        } else if (idxFree == -1) idxFree = idx;
-    };
-
-    // if not subscription exist for the event let's create one
-    if (idx == MAX_SND_CARD) {
+    if(cardId < 0 || cardId >= MAX_SND_CARD) {
+        afb_req_fail_f(request, "devid-invalid", "SndCard cardId=%i invalid", cardId);
+        goto OnErrorExit;
+    }
 
-        // reach MAX_SND_CARD event registration
-        if (idxFree == -1) {
-            afb_req_fail_f(request, "register-toomany", "Cannot register new event Maxcard==%d", idx);
-            goto OnErrorExit;
-        }
+    currentSndHandle = &sndCards->sndHandles[cardId];
 
-        evtHandle = malloc(sizeof (evtHandleT));
-        evtHandle->ctlDev = ctlDev;
-        evtHandle->mode = queryValues.mode;
-        sndHandles[idxFree].ucount = 0;
-        sndHandles[idxFree].cardId = cardId;
-        sndHandles[idxFree].evtHandle = evtHandle;
+    // if not subscription exist for the event let's create one
+    if (! currentSndHandle->evtHandle) {
+        currentSndHandle->evtHandle = malloc(sizeof (ctrlEvtHandleT));
+        currentSndHandle->evtHandle->ctlDev = ctlDev;
+        currentSndHandle->evtHandle->mode = queryValues->mode;
 
         // subscribe for sndctl events attached to devid
-        err = snd_ctl_subscribe_events(evtHandle->ctlDev, 1);
+        err = snd_ctl_subscribe_events(currentSndHandle->evtHandle->ctlDev, 1);
         if (err < 0) {
-            afb_req_fail_f(request, "subscribe-fail", "Cannot subscribe events from devid=%s err=%d", queryValues.devid, err);
+            afb_req_fail_f(request, "subscribe-fail", "Cannot subscribe events from devid=%s err=%d", queryValues->devid, err);
             goto OnErrorExit;
         }
 
         // get pollfd attach to this sound board
-        snd_ctl_poll_descriptors(evtHandle->ctlDev, &evtHandle->pfds, 1);
+        snd_ctl_poll_descriptors(currentSndHandle->evtHandle->ctlDev, &currentSndHandle->evtHandle->pfds, 1);
 
         // register sound event to binder main loop
-        err = sd_event_add_io(afb_daemon_get_event_loop(), &evtHandle->src, evtHandle->pfds.fd, EPOLLIN, sndCtlEventCB, evtHandle);
+        err = sd_event_add_io(afb_daemon_get_event_loop(),
+                              &currentSndHandle->evtHandle->src,
+                              currentSndHandle->evtHandle->pfds.fd,
+                              EPOLLIN,
+                              sndCtlEventCB,
+                              currentSndHandle);
         if (err < 0) {
-            afb_req_fail_f(request, "register-mainloop", "Cannot hook events to mainloop devid=%s err=%d", queryValues.devid, err);
+            afb_req_fail_f(request, "register-mainloop", "Cannot hook events to mainloop devid=%s err=%d", queryValues->devid, err);
             goto OnErrorExit;
         }
 
         // create binder event attached to devid name
-        evtHandle->afbevt = afb_daemon_make_event(queryValues.devid);
-        if (!afb_event_is_valid(evtHandle->afbevt)) {
-            afb_req_fail_f(request, "register-event", "Cannot register new binder event name=%s", queryValues.devid);
+        currentSndHandle->evtHandle->afbevt = afb_daemon_make_event(queryValues->devid);
+        if (!afb_event_is_valid(currentSndHandle->evtHandle->afbevt)) {
+            afb_req_fail_f(request, "register-event", "Cannot register new binder event name=%s", queryValues->devid);
             goto OnErrorExit;
         }
+    }
+    else if (ctlDev) {
+        snd_ctl_close(ctlDev);
+    }
+
+    return currentSndHandle->evtHandle->afbevt;
+
+OnErrorExit:
+    if (ctlDev)
+        snd_ctl_close(ctlDev);
 
-        // everything looks OK let's move forward
-        idx = idxFree;
+    return NULL;
+}
+
+// Subscribe to alsacore event
+PUBLIC void alsaEvtSubcribe(afb_req_t request) {
+    static sndCardsT *sndCards = NULL;
+    afb_event_t eventToSubscribe;
+    int err;
+    queryValuesT queryValues;
+
+    json_object *queryJ;
+
+    if(! sndCards) {
+        sndCards = calloc(1, sizeof(sndCardsT));
     }
 
+    queryJ = alsaCheckQuery(request, &queryValues);
+    if (!queryJ) return;
+
+    eventToSubscribe = alsaEvtSubscribeAlsaControlEvent(request, sndCards, &queryValues);
+
+    if(! eventToSubscribe)
+        return;
+
     // subscribe to binder event
-    err = afb_req_subscribe(request, evtHandle->afbevt);
-    if (err != 0) {
-        afb_req_fail_f(request, "register-eventname", "Cannot subscribe binder event name=%s [invalid channel]", queryValues.devid);
-        goto OnErrorExit;
+    err = afb_req_subscribe(request, eventToSubscribe);
+    if (err) {
+        afb_req_fail_f(request, "register-eventname", "Cannot subscribe binder event");
+        return;
     }
 
-    // increase usage count and return success
-    sndHandles[idx].ucount++;
     afb_req_success(request, NULL, NULL);
-    return;
-
-OnErrorExit:
-    if (ctlDev) snd_ctl_close(ctlDev);
-    return;
 }
 
 // Subscribe to every Alsa CtlEvent send by a given board