/* * 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 #include "AlsaLibMapping.h" #include // 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 (!afb_event_is_valid (evtHandle->afbevt)) { 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 [invalid channel]", devid, err); goto ExitOnError; } // increase usage count and return success sndHandles[idx].ucount ++; afb_req_success(request, NULL, NULL); return; ExitOnError: return; }