Initial working version as independent repo

1 files changed, 395 insertions, 0 deletions

diff --git a/alsa-binding/Alsa-RegEvt.c b/alsa-binding/Alsa-RegEvt.c
new file mode 100644
index 0000000..41db207
--- /dev/null
+++ b/alsa-binding/Alsa-RegEvt.c
@@ -0,0 +1,395 @@
+/*
+ * AlsaLibMapping -- provide low level interface with ALSA lib (extracted from alsa-json-gateway code)
+ * Copyright (C) 2015,2016,2017, Fulup Ar Foll fulup@iot.bzh
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+
+ */
+
+#define _GNU_SOURCE  // needed for vasprintf
+
+#include "Alsa-ApiHat.h"
+
+// generic sndctrl event handle hook to event callback when pooling
+
+typedef struct {
+    struct pollfd pfds;
+    sd_event_source *src;
+    snd_ctl_t *ctlDev;
+    int mode;
+    struct afb_event afbevt;
+} evtHandleT;
+
+typedef struct {
+    int ucount;
+    int cardId;
+    evtHandleT *evtHandle;
+} sndHandleT;
+
+typedef struct {
+    char *devid;
+    char *apiprefix;
+    char *shortname;
+    char *longname;
+} cardRegistryT;
+
+cardRegistryT *cardRegistry[MAX_SND_CARD + 1];
+
+PUBLIC json_object *alsaCheckQuery(afb_req request, queryValuesT *queryValues) {
+
+    json_object *tmpJ;
+    int done;
+
+    // get query from request
+    json_object *queryInJ = afb_req_json(request);
+
+    done = json_object_object_get_ex(queryInJ, "devid", &tmpJ);
+    if (!done) {
+        afb_req_fail_f(request, "devid-missing", "Invalid query='%s'", json_object_get_string(queryInJ));
+        goto OnErrorExit;
+    }
+    queryValues->devid = json_object_get_string(tmpJ);
+
+    done = json_object_object_get_ex(queryInJ, "mode", &tmpJ);
+    if (!done) queryValues->mode = QUERY_QUIET; // default quiet
+    else queryValues->mode = json_object_get_int(tmpJ);
+
+    return queryInJ;
+
+OnErrorExit:
+    return NULL;
+}
+
+// This routine is called when ALSA event are fired
+
+STATIC int sndCtlEventCB(sd_event_source* src, int fd, uint32_t revents, void* userData) {
+    int err, ctlNumid;
+    evtHandleT *evtHandle = (evtHandleT*) userData;
+    snd_ctl_event_t *eventId;
+    json_object *ctlEventJ;
+    unsigned int mask;
+    int iface;
+    int device;
+    int subdev;
+    const char*ctlName;
+    ctlRequestT ctlRequest;
+    snd_ctl_elem_id_t *elemId;
+
+    if ((revents & EPOLLHUP) != 0) {
+        AFB_NOTICE("SndCtl hanghup [car disconnected]");
+        goto ExitOnSucess;
+    }
+
+    if ((revents & EPOLLIN) != 0) {
+
+        // initialise event structure on stack
+        snd_ctl_event_alloca(&eventId);
+        snd_ctl_elem_id_alloca(&elemId);
+
+        err = snd_ctl_read(evtHandle->ctlDev, eventId);
+        if (err < 0) goto OnErrorExit;
+
+        // we only process sndctrl element
+        if (snd_ctl_event_get_type(eventId) != SND_CTL_EVENT_ELEM) goto ExitOnSucess;
+
+        // we only process value changed events
+        mask = snd_ctl_event_elem_get_mask(eventId);
+        if (!(mask & SND_CTL_EVENT_MASK_VALUE)) goto ExitOnSucess;
+
+        snd_ctl_event_elem_get_id(eventId, elemId);
+
+        err = alsaGetSingleCtl(evtHandle->ctlDev, elemId, &ctlRequest, evtHandle->mode);
+        if (err) goto OnErrorExit;
+
+        // If CTL as a value use it as container for response
+        if (ctlRequest.valuesJ) ctlEventJ = ctlRequest.valuesJ;
+        else {
+            ctlEventJ = json_object_new_object();
+            ctlNumid = snd_ctl_event_elem_get_numid(eventId);
+            json_object_object_add(ctlEventJ, "id", json_object_new_int(ctlNumid));
+        }
+
+        if (evtHandle->mode >= QUERY_COMPACT) {
+            ctlName = snd_ctl_event_elem_get_name(eventId);
+            json_object_object_add(ctlEventJ, "name", json_object_new_string(ctlName));
+        }
+
+        if (evtHandle->mode >= QUERY_VERBOSE) {
+            iface = snd_ctl_event_elem_get_interface(eventId);
+            device = snd_ctl_event_elem_get_device(eventId);
+            subdev = snd_ctl_event_elem_get_subdevice(eventId);
+            json_object_object_add(ctlEventJ, "ifc", json_object_new_int(iface));
+            json_object_object_add(ctlEventJ, "dev", json_object_new_int(device));
+            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);
+    }
+
+ExitOnSucess:
+    return 0;
+
+OnErrorExit:
+    AFB_WARNING("sndCtlEventCB: ignored unsupported event type");
+    return (0);
+}
+
+// Subscribe to every Alsa CtlEvent send by a given board
+
+PUBLIC void alsaEvtSubcribe(afb_req request) {
+    static sndHandleT sndHandles[MAX_SND_CARD];
+    evtHandleT *evtHandle = NULL;
+    snd_ctl_t *ctlDev = NULL;
+    int err, idx, cardId, idxFree = -1;
+    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);
+    if (err < 0) {
+        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));
+        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) {
+
+        // 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;
+        }
+
+        evtHandle = malloc(sizeof (evtHandleT));
+        evtHandle->ctlDev = ctlDev;
+        evtHandle->mode = queryValues.mode;
+        sndHandles[idxFree].ucount = 0;
+        sndHandles[idxFree].cardId = cardId;
+        sndHandles[idxFree].evtHandle = evtHandle;
+
+        // subscribe for sndctl events attached to devid
+        err = snd_ctl_subscribe_events(evtHandle->ctlDev, 1);
+        if (err < 0) {
+            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);
+
+        // 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);
+        if (err < 0) {
+            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);
+            goto OnErrorExit;
+        }
+
+        // everything looks OK let's move forward
+        idx = idxFree;
+    }
+
+    // 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;
+    }
+
+    // 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
+
+STATIC json_object *alsaProbeCardId(afb_req request) {
+    char devid [10];
+    const char *ctlName, *shortname, *longname;
+    int card, err, index, idx;
+    json_object *responseJ;
+    snd_ctl_t *ctlDev;
+    snd_ctl_card_info_t *cardinfo;
+
+    const char *sndname = afb_req_value(request, "sndname");
+    if (sndname == NULL) {
+        afb_req_fail_f(request, "argument-missing", "sndname=SndCardName missing");
+        goto OnErrorExit;
+    }
+
+    // loop on potential card number
+    snd_ctl_card_info_alloca(&cardinfo);
+    for (card = 0; card < MAX_SND_CARD; card++) {
+
+        // build card devid and probe it
+        snprintf(devid, sizeof (devid), "hw:%i", card);
+
+        // open control interface for devid
+        err = snd_ctl_open(&ctlDev, devid, SND_CTL_READONLY);
+        if (err < 0) continue;
+
+        // extract sound card information
+        snd_ctl_card_info(ctlDev, cardinfo);
+        index = snd_ctl_card_info_get_card(cardinfo);
+        ctlName = snd_ctl_card_info_get_id(cardinfo);
+        shortname = snd_ctl_card_info_get_name(cardinfo);
+        longname = snd_ctl_card_info_get_longname(cardinfo);
+
+        // check if short|long name match
+        if (!strcmp(sndname, ctlName)) break;
+        if (!strcmp(sndname, shortname)) break;
+        if (!strcmp(sndname, longname)) break;
+    }
+
+    if (card == MAX_SND_CARD) {
+        afb_req_fail_f(request, "ctlDev-notfound", "Fail to find card with name=%s", sndname);
+        goto OnErrorExit;
+    }
+
+    // proxy ctlevent as a binder event
+    responseJ = json_object_new_object();
+    json_object_object_add(responseJ, "index", json_object_new_int(index));
+    json_object_object_add(responseJ, "devid", json_object_new_string(devid));
+    json_object_object_add(responseJ, "shortname", json_object_new_string(shortname));
+    json_object_object_add(responseJ, "longname", json_object_new_string(longname));
+
+    // search for a HAL binder card mapping name to api prefix
+    for (idx = 0; (idx < MAX_SND_CARD && cardRegistry[idx]); idx++) {
+        if (!strcmp(cardRegistry[idx]->shortname, shortname)) {
+            json_object_object_add(responseJ, "halapi", json_object_new_string(cardRegistry[idx]->apiprefix));
+            break;
+        }
+    }
+
+    return responseJ;
+
+OnErrorExit:
+    return NULL;
+}
+
+// Make alsaProbeCardId compatible with AFB request
+
+PUBLIC void alsaGetCardId(afb_req request) {
+
+    json_object *responseJ = alsaProbeCardId(request);
+    if (responseJ) afb_req_success(request, responseJ, NULL);
+}
+
+// Return list of active resgistrated HAL with corresponding sndcard
+
+PUBLIC void alsaActiveHal(afb_req request) {
+    json_object *responseJ = json_object_new_array();
+
+    for (int idx = 0; idx < MAX_SND_CARD; idx++) {
+        if (!cardRegistry[idx]) break;
+
+        json_object *haldevJ = json_object_new_object();
+        json_object_object_add(haldevJ, "api", json_object_new_string(cardRegistry[idx]->apiprefix));
+        if (cardRegistry[idx]->devid) json_object_object_add(haldevJ, "devid", json_object_new_string(cardRegistry[idx]->devid));
+        if (cardRegistry[idx]->shortname)json_object_object_add(haldevJ, "shortname", json_object_new_string(cardRegistry[idx]->shortname));
+        if (cardRegistry[idx]->longname) json_object_object_add(haldevJ, "longname", json_object_new_string(cardRegistry[idx]->longname));
+        json_object_array_add(responseJ, haldevJ);
+    }
+
+    afb_req_success(request, responseJ, NULL);
+}
+
+
+// Register loaded HAL with board Name and API prefix
+
+PUBLIC void alsaRegisterHal(afb_req request) {
+    static int index = 0;
+    json_object *responseJ;
+    const char *shortname, *apiPrefix;
+
+    apiPrefix = afb_req_value(request, "prefix");
+    if (apiPrefix == NULL) {
+        afb_req_fail_f(request, "argument-missing", "prefix=BindingApiPrefix missing");
+        goto OnErrorExit;
+    }
+
+    shortname = afb_req_value(request, "sndname");
+    if (shortname == NULL) {
+        afb_req_fail_f(request, "argument-missing", "sndname=SndCardName missing");
+        goto OnErrorExit;
+    }
+
+    if (index == MAX_SND_CARD) {
+        afb_req_fail_f(request, "alsahal-toomany", "Fail to register sndname=[%s]", shortname);
+        goto OnErrorExit;
+    }
+
+    // alsaGetCardId should be check to register only valid card
+    responseJ = alsaProbeCardId(request);
+    if (responseJ) {
+        json_object *tmpJ;
+        int done;
+
+        cardRegistry[index] = malloc(sizeof (cardRegistry));
+        cardRegistry[index]->apiprefix = strdup(apiPrefix);
+        cardRegistry[index]->shortname = strdup(shortname);
+
+        done = json_object_object_get_ex(responseJ, "devid", &tmpJ);
+        if (done) cardRegistry[index]->devid = strdup(json_object_get_string(tmpJ));
+        else cardRegistry[index]->devid = NULL;
+
+        done = json_object_object_get_ex(responseJ, "longname", &tmpJ);
+        if (done) cardRegistry[index]->longname = strdup(json_object_get_string(tmpJ));
+        else cardRegistry[index]->longname = NULL;
+
+        // make sure register close with a null value
+        index++;
+        cardRegistry[index] = NULL;
+
+        afb_req_success(request, responseJ, NULL);
+    }
+
+    // If OK return sound card Alsa ID+Info
+    return;
+
+OnErrorExit:
+    return;
+}
+