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-rw-r--r--Alsa/core-binding/AlsaLibMapping.c723
1 files changed, 723 insertions, 0 deletions
diff --git a/Alsa/core-binding/AlsaLibMapping.c b/Alsa/core-binding/AlsaLibMapping.c
new file mode 100644
index 0000000..e4f27c9
--- /dev/null
+++ b/Alsa/core-binding/AlsaLibMapping.c
@@ -0,0 +1,723 @@
+/*
+ * 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.
+
+ References:
+ https://github.com/fulup-bzh/AlsaJsonGateway (original code)
+ http://alsa-lib.sourcearchive.com/documentation/1.0.20/modules.html
+ http://alsa-lib.sourcearchive.com/documentation/1.0.8/group__Control_gd48d44da8e3bfe150e928267008b8ff5.html
+ http://alsa.opensrc.org/HowTo_access_a_mixer_control
+ https://github.com/gch1p/alsa-volume-monitor/blob/master/main.c
+
+*/
+
+#define _GNU_SOURCE // needed for vasprintf
+
+#include <alsa/asoundlib.h>
+#include "AlsaLibMapping.h"
+
+#include <systemd/sd-event.h>
+
+// generic structure to pass parsed query values
+typedef struct {
+ const char *devid;
+ int numid;
+ int quiet;
+} queryValuesT;
+
+// generic sndctrl event handle hook to event callback when pooling
+typedef struct {
+ struct pollfd pfds;
+ sd_event_source *src;
+ snd_ctl_t *ctl;
+ struct afb_event afbevt;
+} evtHandleT;
+
+typedef struct {
+ int cardid;
+ int ucount;
+ evtHandleT *evtHandle;
+} sndHandleT;
+
+
+
+
+STATIC json_object *DB2StringJsonOject (long dB) {
+ char label [20];
+ if (dB < 0) {
+ snprintf(label, sizeof(label), "-%li.%02lidB", -dB / 100, -dB % 100);
+ } else {
+ snprintf(label, sizeof(label), "%li.%02lidB", dB / 100, dB % 100);
+ }
+
+ // json function takes care of string copy
+ return (json_object_new_string (label));
+}
+
+
+// Direct port from amixer TLV decode routine. This code is too complex for me.
+// I hopefully did not break it when porting it.
+
+STATIC json_object *decodeTlv(unsigned int *tlv, unsigned int tlv_size) {
+ char label[20];
+ unsigned int type = tlv[0];
+ unsigned int size;
+ unsigned int idx = 0;
+ const char *chmap_type = NULL;
+ json_object * decodeTlvJson = json_object_new_object();
+
+ if (tlv_size < (unsigned int) (2 * sizeof (unsigned int))) {
+ printf("TLV size error!\n");
+ return NULL;
+ }
+ type = tlv[idx++];
+ size = tlv[idx++];
+ tlv_size -= (unsigned int) (2 * sizeof (unsigned int));
+ if (size > tlv_size) {
+ fprintf(stderr, "TLV size error (%i, %i, %i)!\n", type, size, tlv_size);
+ return NULL;
+ }
+ switch (type) {
+
+ case SND_CTL_TLVT_CONTAINER:
+ {
+ json_object * containerJson = json_object_new_array();
+
+ size += (unsigned int) (sizeof (unsigned int) - 1);
+ size /= (unsigned int) (sizeof (unsigned int));
+ while (idx < size) {
+ json_object *embedJson;
+
+ if (tlv[idx + 1] > (size - idx) * sizeof (unsigned int)) {
+ fprintf(stderr, "TLV size error in compound!\n");
+ return NULL;
+ }
+ embedJson = decodeTlv(tlv + idx, tlv[idx + 1] + 8);
+ json_object_array_add(containerJson, embedJson);
+ idx += (unsigned int) (2 + (tlv[idx + 1] + sizeof (unsigned int) - 1) / sizeof (unsigned int));
+ }
+ json_object_object_add(decodeTlvJson, "container", containerJson);
+ break;
+ }
+
+ case SND_CTL_TLVT_DB_SCALE:
+ {
+ json_object * dbscaleJson = json_object_new_object();
+
+ if (size != 2 * sizeof (unsigned int)) {
+ json_object * arrayJson = json_object_new_array();
+ while (size > 0) {
+ snprintf(label, sizeof (label), "0x%08x,", tlv[idx++]);
+ json_object_array_add(arrayJson, json_object_new_string(label));
+ size -= (unsigned int) sizeof (unsigned int);
+ }
+ json_object_object_add(dbscaleJson, "array", arrayJson);
+ } else {
+ json_object_object_add(dbscaleJson, "min", DB2StringJsonOject((int) tlv[2]));
+ json_object_object_add(dbscaleJson, "step", DB2StringJsonOject(tlv[3] & 0xffff));
+ json_object_object_add(dbscaleJson, "mute", DB2StringJsonOject((tlv[3] >> 16) & 1));
+ }
+ json_object_object_add(decodeTlvJson, "dbscale", dbscaleJson);
+ break;
+ }
+
+#ifdef SND_CTL_TLVT_DB_LINEAR
+ case SND_CTL_TLVT_DB_LINEAR:
+ {
+ json_object * dbLinearJson = json_object_new_object();
+
+ if (size != 2 * sizeof (unsigned int)) {
+ json_object * arrayJson = json_object_new_array();
+ while (size > 0) {
+ snprintf(label, sizeof (label), "0x%08x,", tlv[idx++]);
+ json_object_array_add(arrayJson, json_object_new_string(label));
+ size -= (unsigned int) sizeof (unsigned int);
+ }
+ json_object_object_add(dbLinearJson, "offset", arrayJson);
+ } else {
+ json_object_object_add(dbLinearJson, "min", DB2StringJsonOject((int) tlv[2]));
+ json_object_object_add(dbLinearJson, "max", DB2StringJsonOject((int) tlv[3]));
+ }
+ json_object_object_add(decodeTlvJson, "dblinear", dbLinearJson);
+ break;
+ }
+#endif
+
+#ifdef SND_CTL_TLVT_DB_RANGE
+ case SND_CTL_TLVT_DB_RANGE:
+ {
+ json_object *dbRangeJson = json_object_new_object();
+
+ if ((size % (6 * sizeof (unsigned int))) != 0) {
+ json_object *arrayJson = json_object_new_array();
+ while (size > 0) {
+ snprintf(label, sizeof (label), "0x%08x,", tlv[idx++]);
+ json_object_array_add(arrayJson, json_object_new_string(label));
+ size -= (unsigned int) sizeof (unsigned int);
+ }
+ json_object_object_add(dbRangeJson, "dbrange", arrayJson);
+ break;
+ }
+ while (size > 0) {
+ json_object * embedJson = json_object_new_object();
+ snprintf(label, sizeof (label), "%i,", tlv[idx++]);
+ json_object_object_add(embedJson, "rangemin", json_object_new_string(label));
+ snprintf(label, sizeof (label), "%i", tlv[idx++]);
+ json_object_object_add(embedJson, "rangemax", json_object_new_string(label));
+ embedJson = decodeTlv(tlv + idx, 4 * sizeof (unsigned int));
+ json_object_object_add(embedJson, "tlv", embedJson);
+ idx += 4;
+ size -= (unsigned int) (6 * sizeof (unsigned int));
+ json_object_array_add(dbRangeJson, embedJson);
+ }
+ json_object_object_add(decodeTlvJson, "dbrange", dbRangeJson);
+ break;
+ }
+#endif
+#ifdef SND_CTL_TLVT_DB_MINMAX
+ case SND_CTL_TLVT_DB_MINMAX:
+ case SND_CTL_TLVT_DB_MINMAX_MUTE:
+ {
+ json_object * dbMinMaxJson = json_object_new_object();
+
+ if (size != 2 * sizeof (unsigned int)) {
+ json_object * arrayJson = json_object_new_array();
+ while (size > 0) {
+ snprintf(label, sizeof (label), "0x%08x,", tlv[idx++]);
+ json_object_array_add(arrayJson, json_object_new_string(label));
+ size -= (unsigned int) sizeof (unsigned int);
+ }
+ json_object_object_add(dbMinMaxJson, "array", arrayJson);
+
+ } else {
+ json_object_object_add(dbMinMaxJson, "min", DB2StringJsonOject((int) tlv[2]));
+ json_object_object_add(dbMinMaxJson, "max", DB2StringJsonOject((int) tlv[3]));
+ }
+
+ if (type == SND_CTL_TLVT_DB_MINMAX_MUTE) {
+ json_object_object_add(decodeTlvJson, "dbminmaxmute", dbMinMaxJson);
+ } else {
+ json_object_object_add(decodeTlvJson, "dbminmax", dbMinMaxJson);
+ }
+ break;
+ }
+#endif
+#ifdef SND_CTL_TLVT_CHMAP_FIXED
+ case SND_CTL_TLVT_CHMAP_FIXED:
+ chmap_type = "fixed";
+ /* Fall through */
+ case SND_CTL_TLVT_CHMAP_VAR:
+ if (!chmap_type)
+ chmap_type = "variable";
+ /* Fall through */
+ case SND_CTL_TLVT_CHMAP_PAIRED:
+ if (!chmap_type)
+ chmap_type = "paired";
+
+ json_object * chmapJson = json_object_new_object();
+ json_object * arrayJson = json_object_new_array();
+
+ while (size > 0) {
+ snprintf(label, sizeof (label), "%s", snd_pcm_chmap_name(tlv[idx++]));
+ size -= (unsigned int) sizeof (unsigned int);
+ json_object_array_add(arrayJson, json_object_new_string(label));
+ }
+ json_object_object_add(chmapJson, chmap_type, arrayJson);
+ json_object_object_add(decodeTlvJson, "chmap", chmapJson);
+ break;
+#endif
+ default:
+ {
+ printf("unk-%i-", type);
+ json_object * arrayJson = json_object_new_array();
+
+ while (size > 0) {
+ snprintf(label, sizeof (label), "0x%08x,", tlv[idx++]);
+ size -= (unsigned int) sizeof (unsigned int);
+ json_object_array_add(arrayJson, json_object_new_string(label));
+ }
+ break;
+ json_object_object_add(decodeTlvJson, "unknown", arrayJson);
+ }
+ }
+
+ return (decodeTlvJson);
+}
+
+
+// retreive info for one given card
+STATIC json_object* alsaCardProbe (const char *rqtSndId) {
+ const char *info, *name;
+ const char *devid, *driver;
+ json_object *sndcard;
+ snd_ctl_t *handle;
+ snd_ctl_card_info_t *cardinfo;
+ int err;
+
+
+ snd_ctl_card_info_alloca(&cardinfo);
+
+ if ((err = snd_ctl_open(&handle, rqtSndId, 0)) < 0) {
+ INFO (binderIface, "SndCard [%s] Not Found", rqtSndId);
+ return NULL;
+ }
+
+ if ((err = snd_ctl_card_info(handle, cardinfo)) < 0) {
+ snd_ctl_close(handle);
+ WARNING (binderIface, "SndCard [%s] info error: %s", rqtSndId, snd_strerror(err));
+ return NULL;
+ }
+
+ // start a new json object to store card info
+ sndcard = json_object_new_object();
+
+ devid= snd_ctl_card_info_get_id(cardinfo);
+ json_object_object_add (sndcard, "devid" , json_object_new_string(devid));
+ name = snd_ctl_card_info_get_name(cardinfo);
+ json_object_object_add (sndcard, "name", json_object_new_string (name));
+
+ if (binderIface->verbosity > 1) {
+ json_object_object_add (sndcard, "devid", json_object_new_string(rqtSndId));
+ driver= snd_ctl_card_info_get_driver(cardinfo);
+ json_object_object_add (sndcard, "driver" , json_object_new_string(driver));
+ info = strdup(snd_ctl_card_info_get_longname (cardinfo));
+ json_object_object_add (sndcard, "info" , json_object_new_string (info));
+ INFO (binderIface, "AJG: Soundcard Devid=%-5s Cardid=%-7s Name=%s\n", rqtSndId, devid, info);
+ }
+
+ // free card handle and return info
+ snd_ctl_close(handle);
+ return (sndcard);
+}
+
+// Loop on every potential Sound card and register active one
+PUBLIC void alsaGetInfo (struct afb_req request) {
+ int card;
+ json_object *sndcard, *sndcards;
+ char devid[32];
+
+ const char *rqtSndId = afb_req_value(request, "devid");
+
+ // if no specific card requested loop on all
+
+ if (rqtSndId != NULL) {
+ // only one card was requested let's probe it
+ sndcard = alsaCardProbe (rqtSndId);
+ if (sndcard != NULL) afb_req_success(request, sndcard, NULL);
+ else afb_req_fail_f (request, "SndCard [%s] Not Found", rqtSndId);
+
+ } else {
+ // return an array of sndcard
+ sndcards =json_object_new_array();
+
+ // loop on potential card number
+ for (card =0; card < 32; card++) {
+
+ // build card devid and probe it
+ snprintf (devid, sizeof(devid), "hw:%i", card);
+ sndcard = alsaCardProbe (devid);
+
+ // Alsa has hole within card list [ignore them]
+ if (sndcard != NULL) {
+ // add current sndcard to sndcards object
+ json_object_array_add (sndcards, sndcard);
+ }
+ }
+ afb_req_success (request, sndcards, NULL);
+ }
+}
+
+// pack Alsa element's ACL into a JSON object
+STATIC json_object *getControlAcl (snd_ctl_elem_info_t *info) {
+
+ json_object * jsonAclCtl = json_object_new_object();
+
+ json_object_object_add (jsonAclCtl, "read" , json_object_new_boolean(snd_ctl_elem_info_is_readable(info)));
+ json_object_object_add (jsonAclCtl, "write" , json_object_new_boolean(snd_ctl_elem_info_is_writable(info)));
+ json_object_object_add (jsonAclCtl, "inact" , json_object_new_boolean(snd_ctl_elem_info_is_inactive(info)));
+ json_object_object_add (jsonAclCtl, "volat" , json_object_new_boolean(snd_ctl_elem_info_is_volatile(info)));
+ json_object_object_add (jsonAclCtl, "lock" , json_object_new_boolean(snd_ctl_elem_info_is_locked(info)));
+
+ // if TLV is readable we insert its ACL
+ if (!snd_ctl_elem_info_is_tlv_readable(info)) {
+ json_object * jsonTlv = json_object_new_object();
+
+ json_object_object_add (jsonTlv, "read" , json_object_new_boolean(snd_ctl_elem_info_is_tlv_readable(info)));
+ json_object_object_add (jsonTlv, "write" , json_object_new_boolean(snd_ctl_elem_info_is_tlv_writable(info)));
+ json_object_object_add (jsonTlv, "command", json_object_new_boolean(snd_ctl_elem_info_is_tlv_commandable(info)));
+
+ json_object_object_add (jsonAclCtl, "tlv", jsonTlv);
+ }
+ return (jsonAclCtl);
+}
+
+
+
+// pack element from ALSA control into a JSON object
+STATIC json_object * alsaGetSingleCtl (snd_hctl_elem_t *elem, snd_ctl_elem_info_t *info, queryValuesT *queryValues) {
+
+ int err;
+ json_object *jsonAlsaCtl,*jsonClassCtl;
+ snd_ctl_elem_id_t *elemid;
+ snd_ctl_elem_type_t elemtype;
+ snd_ctl_elem_value_t *control;
+ int count, idx;
+
+ // allocate ram for ALSA elements
+ snd_ctl_elem_value_alloca(&control);
+ snd_ctl_elem_id_alloca (&elemid);
+
+ // get elemId out of elem
+ snd_hctl_elem_get_id(elem, elemid);
+
+ // when ctrlid is set, return only this ctrl
+ if (queryValues->numid != -1 && queryValues->numid != snd_ctl_elem_id_get_numid(elemid)) return NULL;
+
+ // build a json object out of element
+ jsonAlsaCtl = json_object_new_object(); // http://alsa-lib.sourcearchive.com/documentation/1.0.24.1-3/group__Control_ga4e4f251147f558bc2ad044e836e449d9.html
+ json_object_object_add (jsonAlsaCtl,"numid", json_object_new_int(snd_ctl_elem_id_get_numid (elemid)));
+ if (queryValues->quiet < 2) json_object_object_add (jsonAlsaCtl,"name" , json_object_new_string(snd_ctl_elem_id_get_name (elemid)));
+ if (queryValues->quiet < 1) json_object_object_add (jsonAlsaCtl,"iface", json_object_new_string(snd_ctl_elem_iface_name(snd_ctl_elem_id_get_interface(elemid))));
+ if (queryValues->quiet < 3)json_object_object_add (jsonAlsaCtl,"actif", json_object_new_boolean(!snd_ctl_elem_info_is_inactive(info)));
+
+ elemtype = snd_ctl_elem_info_get_type(info);
+
+ // number item and value(s) within control.
+ count = snd_ctl_elem_info_get_count (info);
+
+ if (snd_ctl_elem_info_is_readable(info)) {
+ json_object *jsonValuesCtl = json_object_new_array();
+
+ if ((err = snd_hctl_elem_read(elem, control)) < 0) {
+ json_object *jsonValuesCtl = json_object_new_object();
+ json_object_object_add (jsonValuesCtl,"error", json_object_new_string(snd_strerror(err)));
+ } else {
+ for (idx = 0; idx < count; idx++) { // start from one in amixer.c !!!
+ switch (elemtype) {
+ case SND_CTL_ELEM_TYPE_BOOLEAN: {
+ json_object_array_add (jsonValuesCtl, json_object_new_boolean (snd_ctl_elem_value_get_boolean(control, idx)));
+ break;
+ }
+ case SND_CTL_ELEM_TYPE_INTEGER:
+ json_object_array_add (jsonValuesCtl, json_object_new_int ((int)snd_ctl_elem_value_get_integer(control, idx)));
+ break;
+ case SND_CTL_ELEM_TYPE_INTEGER64:
+ json_object_array_add (jsonValuesCtl, json_object_new_int64 (snd_ctl_elem_value_get_integer64(control, idx)));
+ break;
+ case SND_CTL_ELEM_TYPE_ENUMERATED:
+ json_object_array_add (jsonValuesCtl, json_object_new_int (snd_ctl_elem_value_get_enumerated(control, idx)));
+ break;
+ case SND_CTL_ELEM_TYPE_BYTES:
+ json_object_array_add (jsonValuesCtl, json_object_new_int ((int)snd_ctl_elem_value_get_byte(control, idx)));
+ break;
+ case SND_CTL_ELEM_TYPE_IEC958: {
+ json_object *jsonIec958Ctl = json_object_new_object();
+ snd_aes_iec958_t iec958;
+ snd_ctl_elem_value_get_iec958(control, &iec958);
+
+ json_object_object_add (jsonIec958Ctl,"AES0",json_object_new_int(iec958.status[0]));
+ json_object_object_add (jsonIec958Ctl,"AES1",json_object_new_int(iec958.status[1]));
+ json_object_object_add (jsonIec958Ctl,"AES2",json_object_new_int(iec958.status[2]));
+ json_object_object_add (jsonIec958Ctl,"AES3",json_object_new_int(iec958.status[3]));
+ json_object_array_add (jsonValuesCtl, jsonIec958Ctl);
+ break;
+ }
+ default:
+ json_object_array_add (jsonValuesCtl, json_object_new_string ("?unknown?"));
+ break;
+ }
+ }
+ }
+ json_object_object_add (jsonAlsaCtl,"value",jsonValuesCtl);
+ }
+
+
+ if (!queryValues->quiet) { // in simple mode do not print usable values
+ jsonClassCtl = json_object_new_object();
+ json_object_object_add (jsonClassCtl,"type" , json_object_new_string(snd_ctl_elem_type_name(elemtype)));
+ json_object_object_add (jsonClassCtl,"count", json_object_new_int(count));
+
+ switch (elemtype) {
+ case SND_CTL_ELEM_TYPE_INTEGER:
+ json_object_object_add (jsonClassCtl,"min", json_object_new_int((int)snd_ctl_elem_info_get_min(info)));
+ json_object_object_add (jsonClassCtl,"max", json_object_new_int((int)snd_ctl_elem_info_get_max(info)));
+ json_object_object_add (jsonClassCtl,"step", json_object_new_int((int)snd_ctl_elem_info_get_step(info)));
+ break;
+ case SND_CTL_ELEM_TYPE_INTEGER64:
+ json_object_object_add (jsonClassCtl,"min", json_object_new_int64(snd_ctl_elem_info_get_min64(info)));
+ json_object_object_add (jsonClassCtl,"max", json_object_new_int64(snd_ctl_elem_info_get_max64(info)));
+ json_object_object_add (jsonClassCtl,"step", json_object_new_int64(snd_ctl_elem_info_get_step64(info)));
+ break;
+ case SND_CTL_ELEM_TYPE_ENUMERATED: {
+ unsigned int item, items = snd_ctl_elem_info_get_items(info);
+ json_object *jsonEnum = json_object_new_array();
+
+ for (item = 0; item < items; item++) {
+ snd_ctl_elem_info_set_item(info, item);
+ if ((err = snd_hctl_elem_info(elem, info)) >= 0) {
+ json_object_array_add (jsonEnum, json_object_new_string(snd_ctl_elem_info_get_item_name(info)));
+ }
+ }
+ json_object_object_add (jsonClassCtl, "enums",jsonEnum);
+ break;
+ }
+ default: break; // ignore any unknown type
+ }
+
+ // add collected class info with associated ACLs
+ json_object_object_add (jsonAlsaCtl,"ctrl", jsonClassCtl);
+ json_object_object_add (jsonAlsaCtl,"acl" , getControlAcl (info));
+
+ // check for tlv [direct port from amixer.c]
+ if (snd_ctl_elem_info_is_tlv_readable(info)) {
+ unsigned int *tlv;
+ tlv = malloc(4096);
+ if ((err = snd_hctl_elem_tlv_read(elem, tlv, 4096)) < 0) {
+ fprintf (stderr, "Control %s element TLV read error\n", snd_strerror(err));
+ free(tlv);
+ } else {
+ json_object_object_add (jsonAlsaCtl,"tlv", decodeTlv (tlv, 4096));
+ }
+ }
+ }
+ return (jsonAlsaCtl);
+}
+
+
+PUBLIC void alsaGetCtl(struct afb_req request) {
+ int err = 0;
+ snd_hctl_t *handle;
+ snd_hctl_elem_t *elem;
+ snd_ctl_elem_info_t *info;
+ json_object *sndctrls, *control;
+ queryValuesT queryValues;
+
+ // get API params
+ queryValues.devid = afb_req_value(request, "devid");
+
+ const char *rqtNumid = afb_req_value(request, "numid");
+ if (!rqtNumid) queryValues.numid=-1;
+ else if (rqtNumid && ! sscanf (rqtNumid, "%d", &queryValues.numid)) {
+ json_object *query = afb_req_json(request);
+
+ afb_req_fail_f (request, "Query=%s NumID not integer &numid=%s&", json_object_to_json_string(query), rqtNumid);
+ goto ExitOnError;
+ };
+
+ const char *rqtQuiet = afb_req_value(request, "quiet");
+ if (!rqtQuiet) queryValues.quiet=99; // default super quiet
+ else if (rqtQuiet && ! sscanf (rqtQuiet, "%d", &queryValues.quiet)) {
+ json_object *query = afb_req_json(request);
+
+ afb_req_fail_f (request, "Query=%s NumID not integer &numid=%s&", json_object_to_json_string(query), rqtQuiet);
+ goto ExitOnError;
+ };
+
+ // Open sound we use Alsa high level API like amixer.c
+ if (!queryValues.devid || (err = snd_hctl_open(&handle, queryValues.devid, 0)) < 0) {
+ afb_req_fail_f (request, "alsaGetControl devid=[%s] open fail error=%s\n", queryValues.devid, snd_strerror(err));
+ goto ExitOnError;
+ }
+
+ if ((err = snd_hctl_load(handle)) < 0) {
+ afb_req_fail_f (request, "alsaGetControl devid=[%s] load fail error=%s\n", queryValues.devid, snd_strerror(err));
+ goto ExitOnError;
+ }
+
+ // allocate ram for ALSA elements
+ snd_ctl_elem_info_alloca(&info);
+
+ // create an json array to hold all sndcard response
+ sndctrls = json_object_new_array();
+
+ for (elem = snd_hctl_first_elem(handle); elem != NULL; elem = snd_hctl_elem_next(elem)) {
+
+ if ((err = snd_hctl_elem_info(elem, info)) < 0) {
+ json_object_put(sndctrls); // we abandon request let's free response
+ afb_req_fail_f (request, "alsaGetControl devid=[%s/%s] snd_hctl_elem_info error: %s\n"
+ , queryValues.devid, snd_hctl_name(handle), snd_strerror(err));
+ goto ExitOnError;
+ }
+
+ // each control is added into a JSON array
+ control = alsaGetSingleCtl(elem, info, &queryValues);
+ if (control) json_object_array_add(sndctrls, control);
+
+ }
+
+ afb_req_success (request, sndctrls, NULL);
+ return;
+
+ // nothing special only for debugger breakpoint
+ ExitOnError:
+ return;
+}
+
+STATIC int sndCtlEventCB (sd_event_source* src, int fd, uint32_t revents, void* userData) {
+ int err;
+ evtHandleT *evtHandle = (evtHandleT*)userData;
+ snd_ctl_event_t *ctlEvent;
+ json_object *ctlEventJson;
+ unsigned int mask;
+ int numid;
+ int iface;
+ int device;
+ int subdev;
+ const char*devname;
+ int index;
+
+ if ((revents & EPOLLHUP) != 0) {
+ NOTICE (binderIface, "SndCtl hanghup [car disconnected]");
+ goto ExitOnSucess;
+ }
+
+ if ((revents & EPOLLIN) != 0) {
+
+ snd_ctl_event_alloca(&ctlEvent); // initialise event structure on stack
+
+ err = snd_ctl_read(evtHandle->ctl, ctlEvent);
+ if (err < 0) goto ExitOnError;
+
+ // we only process sndctrl element
+ if (snd_ctl_event_get_type(ctlEvent) != SND_CTL_EVENT_ELEM) goto ExitOnSucess;
+
+ // we only process value changed events
+ mask = snd_ctl_event_elem_get_mask(ctlEvent);
+ if (!(mask & SND_CTL_EVENT_MASK_VALUE)) goto ExitOnSucess;
+
+ numid = snd_ctl_event_elem_get_numid(ctlEvent);
+ iface = snd_ctl_event_elem_get_interface(ctlEvent);
+ device = snd_ctl_event_elem_get_device(ctlEvent);
+ subdev = snd_ctl_event_elem_get_subdevice(ctlEvent);
+ devname= snd_ctl_event_elem_get_name(ctlEvent);
+ index = snd_ctl_event_elem_get_index(ctlEvent);
+
+ fprintf(stdout, "*** Debug (%i,%i,%i,%i,%s,%i)", numid, iface, device, subdev, devname, index);
+
+ // proxy ctlevent as a binder event
+ ctlEventJson = json_object_new_object();
+ json_object_object_add(ctlEventJson, "numid" ,json_object_new_int (numid));
+ json_object_object_add(ctlEventJson, "iface" ,json_object_new_int (iface));
+ json_object_object_add(ctlEventJson, "device" ,json_object_new_int (device));
+ json_object_object_add(ctlEventJson, "subdev" ,json_object_new_int (subdev));
+ json_object_object_add(ctlEventJson, "devname",json_object_new_string (devname));
+ json_object_object_add(ctlEventJson, "index" ,json_object_new_int (index));
+ afb_event_push(evtHandle->afbevt, ctlEventJson);
+ }
+
+
+ ExitOnError:
+ WARNING (binderIface, "sndCtlEventCB: ignored unsupported event type");
+ return (0);
+
+ ExitOnSucess:
+ return 0;
+}
+
+// Loop on every potential Sound card and register active one
+PUBLIC void alsaSubCtl (struct afb_req request) {
+ static sndHandleT sndHandles[MAX_SND_CARD];
+ evtHandleT *evtHandle;
+ snd_ctl_t *ctlHandle;
+ snd_ctl_card_info_t *card_info;
+ int err, idx, cardid;
+ int idxFree=-1;
+
+ const char *devid = afb_req_value(request, "devid");
+ if (devid == NULL) {
+ afb_req_fail_f (request, "devid-missing", "devid=hw:xxx missing");
+ goto ExitOnError;
+ }
+
+ // open control interface for devid
+ err = snd_ctl_open(&ctlHandle, devid, SND_CTL_READONLY);
+ if (err < 0) {
+ afb_req_fail_f (request, "devid-unknown", "SndCard devid=%s Not Found err=%d", devid, err);
+ goto ExitOnError;
+ }
+
+ // get sound card index use to search existing subscription
+ snd_ctl_card_info_alloca(&card_info);
+ snd_ctl_card_info(ctlHandle, card_info);
+ cardid = snd_ctl_card_info_get_card(card_info);
+
+ // search for an existing subscription and mark 1st free slot
+ for (idx= 0; idx < MAX_SND_CARD; idx ++) {
+ if (sndHandles[idx].ucount > 0 && sndHandles[idx].cardid == 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==%devent name=%s", idx);
+ snd_ctl_close(ctlHandle);
+ goto ExitOnError;
+ }
+
+ evtHandle = malloc (sizeof(evtHandleT));
+ evtHandle->ctl = ctlHandle;
+ sndHandles[idxFree].ucount = 0;
+ sndHandles[idxFree].cardid = cardid;
+
+ // subscribe for sndctl events attached to devid
+ err = snd_ctl_subscribe_events(evtHandle->ctl, 1);
+ if (err < 0) {
+ afb_req_fail_f (request, "subscribe-fail", "Cannot subscribe events from devid=%s err=%d", devid, err);
+ snd_ctl_close(ctlHandle);
+ goto ExitOnError;
+ }
+
+ // get pollfd attach to this sound board
+ snd_ctl_poll_descriptors(evtHandle->ctl, &evtHandle->pfds, 1);
+
+ // register sound event to binder main loop
+ err = sd_event_add_io(afb_daemon_get_event_loop(binderIface->daemon), &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", devid, err);
+ snd_ctl_close(ctlHandle);
+ goto ExitOnError;
+ }
+
+ // create binder event attached to devid name
+ evtHandle->afbevt = afb_daemon_make_event (binderIface->daemon, devid);
+ if (!evtHandle->afbevt.closure) {
+ afb_req_fail_f (request, "register-event", "Cannot register new binder event name=%s", devid);
+ snd_ctl_close(ctlHandle);
+ goto ExitOnError;
+ }
+
+ // 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 err=%d", devid, err);
+ goto ExitOnError;
+ }
+
+ sndHandles[idx].ucount ++;
+ afb_req_success(request, NULL, NULL);
+ return;
+
+ ExitOnError:
+ return;
+}