summaryrefslogtreecommitdiffstats
path: root/alsa-hook/PolicyAlsaHook.c
blob: 3a48f83db5afc020398f2ca7bc3190ef6052e598 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
/*
 * Copyright (C) 2016 "IoT.bzh"
 * Author 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.
 *
 * AfbCallBack (snd_ctl_hal_t *handle, int numid, void **response);
 *  AlsaHookInit is mandatory and called with numid=0
 *
 * Syntax in .asoundrc file
 *   CrlLabel    { cb MyFunctionName name "My_Second_Control" }
 *
 * Testing:
 *   aplay -DAlsaHook /usr/share/sounds/alsa/test.wav
 *
 * References:
 *  https://www.spinics.net/lists/alsa-devel/msg54235.html
 *  https://github.com/shivdasgujare/utilities/blob/master/nexuss/alsa-scenario-hook/src/alsa-wrapper.c
 */

#define _GNU_SOURCE
#include <stdio.h>
#include <alloca.h>

#include <alsa/asoundlib.h>
#include <alsa/conf.h>
#include <alsa/pcm.h>

#include <systemd/sd-event.h>
#include <json-c/json.h>

#include "afb/afb-wsj1.h"
#include "afb/afb-ws-client.h"
#include "afb/afb-proto-ws.h"

#include <pthread.h>
#include <semaphore.h>

#define PLUGIN_ENTRY_POINT AlsaInstallHook
    // Fulup Note: What ever you may find on Internet you should use
    // SND_CONFIG_DLSYM_VERSION_HOOK and not SND_CONFIG_DLSYM_VERSION_HOOK
    SND_DLSYM_BUILD_VERSION(PLUGIN_ENTRY_POINT, SND_PCM_DLSYM_VERSION)

// this should be more than enough
#define MAX_API_CALL 10
#define MAX_EVT_CALL 10

// timeout in ms
#define REQUEST_DEFAULT_TIMEOUT 500
#ifndef MAINLOOP_WATCHDOG
#define MAINLOOP_WATCHDOG 100000
#endif

// closing message is added to query when PCM is closed
#define CLOSING_MSG ",\"source\":-1}"

// Currently not implemented
#define UNUSED_ARG(x) UNUSED_ ## x __attribute__((__unused__))
#define  MAGIC_HOOK 22562935

typedef struct {
    char *apiverb;
    json_object *queryJ;
    sd_event_source *evtSource;
    char *callIdTag;
    void *afbClient;
} afbRequestT;

typedef struct {
    char *search;
    char *value;
    long ivalue;
    int signal;
} afbEventT;

typedef struct {
    long magic;
    char *name;
    char *uid;
    snd_pcm_t *pcm;
    char *uri;
    struct afb_proto_ws *pws;
    sd_event *sdLoop;
    int verbose;
    int synchronous;
    sem_t semaphore;
    long timeout;
    int count;
    int errcount;
    afbRequestT **request;
    afbRequestT **release;
    afbEventT **event;
    pthread_t tid;
    json_object * streamIdJ;
} afbClientT;


static void *LoopInThread(void *handle) {
    afbClientT *afbClient = (afbClientT*) handle;
    int count=0;
    int watchdog= MAINLOOP_WATCHDOG *1000;

    /* loop until end */
    for (;;) {

        if (afbClient->verbose) printf("ON-MAINLOOP Session=%s ping=%d\n", afbClient->uid, count++);
        int  res = sd_event_run(afbClient->sdLoop, watchdog);

        if ( res < 0 )
        {
            printf("ERROR in LoopInThread \"%i\" Break ON-MAINLOOP errno=%s.\n", res, strerror(errno));
            break;
        }
    }
    pthread_exit(0);
}

// lost connect with the AudioDaemon
static void OnHangupCB(void *handle) {

    afbClientT *afbClient = (afbClientT*) handle;
    SNDERR("(Hoops) Lost Connection to %s", afbClient->uri);

    // try to close PCM when impossible terminate client
    int err = snd_pcm_close (afbClient->pcm);
    if (err) exit(1);
}

typedef enum {
    HOOK_INSTALL,
    HOOK_CLOSE,
} hookActionT;

void OnEventCB(void *handle, const char *event, int evtid, struct json_object *dataJ) {
    afbClientT *afbClient = (afbClientT*) handle;
    afbEventT **afbEvent = afbClient->event;
    json_object *tmpJ;
    int signal=0, index;

    // if no event handler just ignore events
    if (!afbEvent) goto OnErrorExit;

    if (afbClient->verbose) printf("ON-EVENT processing signal event=%s search=%s session=%s\n", event, json_object_get_string(dataJ), afbClient->uid);

    // loop on event/signal mapping table
    for (index=0; afbEvent[index]!= NULL; index++) {
        int done;

        done = json_object_object_get_ex(dataJ,afbEvent[index]->search, &tmpJ);
        if (done) {

            if (afbEvent[index]->value) {
                // search value is a string
                if (json_object_get_type(tmpJ) != json_type_string) goto OnErrorExit;
                const char *value=json_object_get_string(tmpJ);
                if (!strcmp(afbEvent[index]->value, value)) signal=afbEvent[index]->signal;

            } else {

                // search value is an integer
                if (json_object_get_type(tmpJ) != json_type_int) goto OnErrorExit;
                int ivalue=json_object_get_int(tmpJ);
                if (ivalue == afbEvent[index]->ivalue) signal=afbEvent[index]->signal;
            }
            break;
       }
    }
    if (signal) {
        if (afbClient->verbose) printf("ON-EVENT self-signal search=%s signal=%d\n", afbEvent[index]->search, afbEvent[index]->signal);
        if (afbEvent[index]->signal) kill (getpid(), afbEvent[index]->signal);
    }

    return;

OnErrorExit:
    if (afbClient->verbose) SNDERR("ON-EVENT Fail/Ignored %s(%s)\n", event, json_object_get_string(dataJ));
    return;
}

static void OnSuccessCB(void* UNUSED_ARG(ctx) , void* handle, json_object* responseJ, const char* info) {

    afbRequestT *afbRequest= (afbRequestT*)handle;
    afbClientT *afbClient=(afbClientT*)afbRequest->afbClient;

    if (afbClient->verbose) printf("OnSuccessCB callid='%s' response='%s' info='%s'\n", afbRequest->callIdTag, json_object_get_string(responseJ), info);

    // as pulse does not close PCM even timeout=0 session is not enough and we have to handle stream_id manually
    if (json_object_object_get_ex(responseJ, "stream_id", &afbClient->streamIdJ) && afbClient->verbose) {
        json_object_get(afbClient->streamIdJ);
        printf("OnSuccessCB session store stream_id='%s'\n", json_object_get_string(afbClient->streamIdJ));
    }

    // Cancel timeout for this request
    sd_event_source_unref(afbRequest->evtSource);
    free(afbRequest->callIdTag);

    // When not more waiting call release semaphore
    afbClient->count--;
    if (afbClient->synchronous) {
        if (afbClient->verbose) printf("OnSuccessCB One Request Done\n");
        sem_post (&afbClient->semaphore);
    } else if (afbClient->count == 0) {
        if (afbClient->verbose) printf("OnSuccessCB No More Waiting Request\n");
        sem_post (&afbClient->semaphore);
    }
}

static void OnFailureCB(void* UNUSED_ARG(ctx), void* handle, const char *status, const char *info) {

    afbRequestT *afbRequest= (afbRequestT*)handle;
    afbClientT *afbClient=(afbClientT*)afbRequest->afbClient;

    if (afbClient->verbose) printf("OnFailureCB callid='%s' status='%s' info='%s'\n", afbRequest->callIdTag, status, info);

    // Cancel timeout for this request
    sd_event_source_unref(afbRequest->evtSource);
    free(afbRequest->callIdTag);

    afbClient->errcount++;
    sem_post (&afbClient->semaphore);
}

#if defined(AFB_PROTO_WS_VERSION) && (AFB_PROTO_WS_VERSION >= 3)
static void OnReplyCB(void* ctx, void* handle, json_object* responseJ, const char *error, const char *info) {
    if (error)
        OnFailureCB(ctx, handle, error, info);
    else
        OnSuccessCB(ctx , handle, responseJ, info);
}
#endif

/* the callback interface for pws */
static struct afb_proto_ws_client_itf itf = {
#if defined(AFB_PROTO_WS_VERSION) && (AFB_PROTO_WS_VERSION >= 3)
    .on_reply = OnReplyCB,
#else
    .on_reply_success = OnSuccessCB,
    .on_reply_fail = OnFailureCB,
#endif
    .on_event_create = NULL,
    .on_event_remove = NULL,
    .on_event_subscribe = NULL,
    .on_event_unsubscribe = NULL,
    .on_event_push = OnEventCB,
    .on_event_broadcast = NULL,
    .on_subcall = NULL,
};

int OnTimeoutCB (sd_event_source* source, uint64_t timer, void* handle) {
    afbClientT *afbClient= (afbClientT*)handle;

    SNDERR("\nON-TIMEOUT Call Request Fail session=%s\n", afbClient->uid );

    // Close PCM and release waiting client
    afbClient->errcount=1;
    sem_post (&afbClient->semaphore);

    return 0;
}

// Call AGL binder asynchronously by with a timeout
static int CallWithTimeout(afbClientT *afbClient, afbRequestT *afbRequest, int count) {
    uint64_t usec;
    json_object *queryJ;
    int err;

    // create a unique tag for request
    (void)asprintf(&afbRequest->callIdTag, "%d:%s", count, afbRequest->apiverb);

    // create a timer with ~250us accuracy
    sd_event_now(afbClient->sdLoop, CLOCK_MONOTONIC, &usec);
    sd_event_add_time(afbClient->sdLoop, &afbRequest->evtSource, CLOCK_MONOTONIC, usec+afbClient->timeout*1000, 250, OnTimeoutCB, afbClient);

    // if steamId is set then add it to api query
    if (!afbClient->streamIdJ) {
       queryJ=afbRequest->queryJ;
    } else {
       queryJ=json_object_new_object();
       json_object_object_foreach(afbRequest->queryJ, key, obj) {
         json_object_object_add(queryJ, key, obj);
       }
        json_object_object_add(queryJ,"stream_id",afbClient->streamIdJ);
    }

    // release action is optional
    if (afbRequest->apiverb) {
        if (afbClient->verbose)  printf("CALL-REQUEST verb=%s query=%s tag=%s session=%s\n", afbRequest->apiverb, json_object_get_string(queryJ), afbRequest->callIdTag, afbClient->uid);
        err = afb_proto_ws_client_call(afbClient->pws, afbRequest->apiverb, queryJ, afbClient->uid, afbRequest);
        if (err < 0 ) goto OnErrorExit;
    }

    // save client handle in request
    afbRequest->afbClient = afbClient;
    afbClient->count ++;

    // in synchronous mode we wait for CB to return
    if (afbClient->synchronous) {
        sem_wait(&afbClient->semaphore);
        if (afbClient->errcount) {
            printf("CALL-REQUEST FAILED afbClient->errcount=%d session=%s \n", afbClient->errcount,afbClient->uid);
            goto OnErrorExit;
        }
    }

    return 0;

OnErrorExit:
    fprintf(stderr, "LaunchCallRequest: Fail ws-client=%s query=%s&%s\n", afbClient->uri, afbRequest->apiverb, json_object_get_string(afbRequest->queryJ));
    return 1;
}

static int LaunchCallRequest(afbClientT *afbClient, hookActionT action) {
    int err, idx;

    // each callback on error add one to error count.

    afbClient->errcount = 0;

    switch (action) {
        case HOOK_INSTALL: {
            if (afbClient->verbose) printf("HOOK_INSTALL Session=%s\n", afbClient->uid);
            // init waiting counting semaphore
            if (sem_init(&afbClient->semaphore, 1, 0) == -1) {
               fprintf(stderr, "LaunchCallRequest: Fail Semaphore Init: %s\n", afbClient->uri);
            }

            // Create a main loop
            err = sd_event_new(&afbClient->sdLoop);
            if (err < 0) {
                fprintf(stderr, "LaunchCallRequest: Connection to default event loop failed: %s\n", strerror(-err));
                goto OnErrorExit;
            }

            // start a thread with a mainloop to monitor Audio-Agent
            err = pthread_create(&afbClient->tid, NULL, &LoopInThread, afbClient);
            if (err) goto OnErrorExit;

            afbClient->pws = afb_ws_client_connect_api(afbClient->sdLoop, afbClient->uri, &itf, afbClient);
            if (afbClient->pws == NULL) {
                fprintf(stderr, "LaunchCallRequest: Connection to %s failed\n", afbClient->uri);
                goto OnErrorExit;
            }
            if (afbClient->verbose) printf ("LaunchCallRequest:optional HOOK_OPEN uri=%s\n", afbClient->uri);

            // register hanghup callback
            afb_proto_ws_on_hangup(afbClient->pws, OnHangupCB);


            // If no request exit now
            if (!afbClient->release) {
                fprintf(stderr, "LaunchCallRequest: HOOK_INSTALL:fatal mandatory request call missing in asoundrc\n");
                goto OnErrorExit;;
            }

            // send call request to audio-agent asynchronously (respond with thread mainloop context)
            for (idx = 0; afbClient->request[idx] != NULL; idx++) {
                err = CallWithTimeout(afbClient, afbClient->request[idx], idx);
                if (err) goto OnErrorExit;
            }
            // launch counter to keep track of waiting request call
            afbClient->count=idx;
            break;
        }

        case HOOK_CLOSE: {
            if (afbClient->verbose) printf("HOOK_CLOSE Session=%s\n", afbClient->uid);
            // If no request exit now
            if (!afbClient->release) {
                if (afbClient->verbose) printf("LaunchCallRequest:optional HOOK_CLOSE no release control call\n");
                break;
            }

            // send call request to audio-agent asynchronously (respond with thread mainloop context)
            for (idx = 0; afbClient->release[idx] != NULL; idx++) {
                err = CallWithTimeout(afbClient, afbClient->release[idx], idx);
                if (err) goto OnErrorExit;
            }
            // launch counter to keep track of waiting request call
            afbClient->count=idx;
            break;
        }

    default:
       fprintf(stderr, "LaunchCallRequest (hoops): Unknown action");
       goto OnErrorExit;
    }

    return 0;

OnErrorExit:
    return 1;
}

static void AlsaHookClean (afbClientT *afbClient)
{
    free(afbClient->uid);
    free(afbClient->name);
    free(afbClient->uri);
    if (afbClient->event) {
        afbEventT **afbEvent=afbClient->event;
        for (int index=0; afbEvent[index]!= NULL; index++) {
            free(afbEvent[index]->search);
            free(afbEvent[index]->value);
        }
        free(afbEvent);
    }
    if (afbClient->request) {
        afbRequestT **afbRequest=afbClient->request;
        for (int index=0; afbRequest[index]!= NULL; index++) {
            free(afbRequest[index]->apiverb);
            json_object_put(afbRequest[index]->queryJ);
        }
        free(afbRequest);
    }
    if (afbClient->release) {
        afbRequestT **afbRelease=afbClient->release;
        for (int index=0; afbRelease[index]!= NULL; index++) {
            free(afbRelease[index]->apiverb);
            json_object_put(afbRelease[index]->queryJ);
        }
        free(afbRelease);
    }
    afbClient->magic=0;

    // free systemd loop
    if (afbClient->sdLoop) sd_event_unref(afbClient->sdLoop);
    if (afbClient->streamIdJ) json_object_put(afbClient->streamIdJ);
    // close binder websocket
    //ISSUE for Jose
    //if (afbClient->pws) afb_proto_ws_unref(afbClient->pws);
    free(afbClient);
}

static int AlsaCloseHook(snd_pcm_hook_t *hook) {

    afbClientT *afbClient = (afbClientT*) snd_pcm_hook_get_private (hook);
    //hook is already close
    if (!afbClient || afbClient->magic != MAGIC_HOOK ) {
        if (afbClient->verbose) printf("AlsaCloseHook Ignored, invalid afbClient\n");
        return 0;
    }
    // launch call request and create a waiting mainloop thread
    int err = LaunchCallRequest(afbClient, HOOK_CLOSE);
    if (err < 0) {
        fprintf (stderr, "Error on PCM Release Call\n");
        goto OnErrorExit;
    }

    // wait for all call request to return
    if (afbClient->errcount) {
        fprintf (stderr, "AlsaCloseHook: Notice exit before audio-4a response\n");
        goto OnErrorExit;
    }

    // request main loop to terminate without signal
    if (afbClient->verbose) printf("AlsaCloseHook: Start pthread_cancel request\n");
    int s = pthread_cancel(afbClient->tid);
    if (s != 0)
       printf("AlsaCloseHook: ERROR on pthread_cancel err %d\n",s);

    /* Join with thread to see what its exit status was */
    void *res;
    s = pthread_join(afbClient->tid, &res);
    if (s != 0)
        printf("AlsaCloseHook: ERROR on pthread_join err %d\n",s);

    if (res == PTHREAD_CANCELED) {
        if (afbClient->verbose) fprintf(stdout, "\nAlsaHook Close Success PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
    } else {
        printf("AlsaCloseHook: EventLoop thread failed to canceled (shouldn't happen!)\n");
    }

    AlsaHookClean(afbClient);
    snd_pcm_hook_set_private(hook,NULL);
    return 0;

OnErrorExit:
    fprintf(stderr, "\nAlsaPcmHook Plugin Close Fail PCM=%s\n", snd_pcm_name(afbClient->pcm));
    return 0;
}

// Get an asoundrc compound and return it as a JSON object
static json_object* AlsaGetJson (snd_config_t *ctlconfig, const char *id, const char*label) {

    json_object *queryJ;
    snd_config_type_t ctype;
    char* query;

    // each control is a sting that contain a json object
    ctype = snd_config_get_type(ctlconfig);
    snd_config_get_string(ctlconfig,  (const char**) &query);
    if (ctype != SND_CONFIG_TYPE_STRING) {
        SNDERR("Invalid signal number for %s value=%s", label, query);
        goto OnErrorExit;
    }

    // cleanup string for json_tokener
    for (int idx = 0; query[idx] != '\0'; idx++) {
        if (query[idx] == '\'') query[idx] = '"';
    }
    queryJ = json_tokener_parse(query);
    if (!queryJ) {
        SNDERR("Not a valid Json object control='%s' query='%s'", id, query);
        goto OnErrorExit;
    }

    return queryJ;

OnErrorExit:
    return NULL;
}

static int AlsaGetActions (snd_config_t *node, afbRequestT **afbRequest, const char*id) {
    const char *callConf, *apiverb;
    snd_config_type_t ctype;
    snd_config_iterator_t currentCall, follow;
    int callCount=0;

    ctype = snd_config_get_type(node);
    if (ctype != SND_CONFIG_TYPE_COMPOUND) {
        snd_config_get_string(node, &callConf);
        SNDERR("Invalid compound type for %s", callConf);
        goto OnErrorExit;
    }


    // loop on each call
    snd_config_for_each(currentCall, follow, node) {
        snd_config_t *ctlconfig = snd_config_iterator_entry(currentCall);

        // ignore empty line
        if (snd_config_get_id(ctlconfig, &apiverb) < 0) continue;

        // allocate an empty call request
        afbRequest[callCount] = calloc(1, sizeof (afbRequestT));
        afbRequest[callCount]->apiverb=strdup(apiverb);
        afbRequest[callCount]->queryJ= AlsaGetJson(ctlconfig, id, apiverb);
        if (!afbRequest[callCount]->queryJ) goto OnErrorExit;

        // move to next call if any
        callCount ++;
        if (callCount == MAX_EVT_CALL) {
            SNDERR("Too Many call MAX_EVT_CALL=%d", MAX_EVT_CALL);
            goto OnErrorExit;
        }
        afbRequest[callCount]=NULL; // afbEvent array is NULL terminated
    }

    return 0;

OnErrorExit:
    return 1;
}

static int AlsaGetEvents (snd_config_t *node, afbEventT **afbEvent, const char*id) {

    const char *confEvents, *evtpattern;
    snd_config_type_t ctype;
    snd_config_iterator_t currentEvt, follow;
    snd_config_t *itemConf;
    int callCount=0;
    int err;

    ctype = snd_config_get_type(node);
    if (ctype != SND_CONFIG_TYPE_COMPOUND) {
        snd_config_get_string(node, &confEvents);
        SNDERR("Invalid compound type for %s", confEvents);
        goto OnErrorExit;
    }

    // loop on each call
    snd_config_for_each(currentEvt, follow, node) {
        snd_config_t *ctlconfig = snd_config_iterator_entry(currentEvt);

        // ignore empty line
        if (snd_config_get_id(ctlconfig, &evtpattern) < 0) continue;

        // allocate an empty call request
        afbEvent[callCount] = calloc(1, sizeof (afbEventT));

        // extract signal num from config label
        for (int idx=0; evtpattern[idx] != '\0'; idx++) {
            if (evtpattern[idx]=='-' && evtpattern[idx+1] != '\0') {
                int done= sscanf (&evtpattern[idx+1], "%d",&afbEvent[callCount]->signal);
                if (done != 1) {
                    SNDERR("Invalid Signal '%s' definition should be something like Sig-xx", evtpattern);
                    goto OnErrorExit;
                }
                break;
            }
        }

        // extract signal key value search pattern
        ctype = snd_config_get_type(ctlconfig);
        if (ctype != SND_CONFIG_TYPE_COMPOUND) {
            snd_config_get_string(ctlconfig, &confEvents);
            SNDERR("Invalid event search pattern for %s value=%s", evtpattern, confEvents);
            goto OnErrorExit;
        }

        // pattern should have a search
        err = snd_config_search(ctlconfig, "search", &itemConf);
        if (!err) {
            const char *search;
            if (snd_config_get_string(itemConf, &search) < 0) {
                SNDERR("Invalid event/signal 'search' should be a string %s", confEvents);
                goto OnErrorExit;
            }
            afbEvent[callCount]->search=strdup(search);
        } else {
            SNDERR("Missing 'search' from event/signal 'search' from signal definition %s", confEvents);
            goto OnErrorExit;
        }

        // pattern should have a value
        err = snd_config_search(ctlconfig, "value", &itemConf);
        if (!err) {
            const char *value;
            switch (snd_config_get_type(itemConf)) {
                case SND_CONFIG_TYPE_INTEGER:
                    snd_config_get_integer(itemConf, &afbEvent[callCount]->ivalue);
                    break;

                case  SND_CONFIG_TYPE_STRING:
                    snd_config_get_string(itemConf, &value);
                    afbEvent[callCount]->value=strdup(value);
                    break;
                default:
                    SNDERR("Invalid event/signal 'value' should be a string %s", confEvents);
                    goto OnErrorExit;
            }
        } else {
            SNDERR("Missing 'value' from event/signal 'value' from signal definition %s", confEvents);
            goto OnErrorExit;
        }

        // move to next call if any
        callCount ++;
        if (callCount == MAX_EVT_CALL) {
            SNDERR("Too Many call MAX_EVT_CALL=%d", MAX_EVT_CALL);
            goto OnErrorExit;
        }
        afbEvent[callCount]=NULL; // afbEvent array is NULL terminated
    }
    return 0;

OnErrorExit:
    return 1;
}

// Function call when Plugin PCM is OPEN
int PLUGIN_ENTRY_POINT (snd_pcm_t *pcm, snd_config_t *conf) {
    snd_pcm_hook_t *h_close = NULL;
    snd_config_iterator_t it, next;
    afbClientT *afbClient = calloc(1,sizeof (afbClientT));
    int err;

    // start populating client handle
    afbClient->pcm = pcm;
    afbClient->name= strdup(snd_pcm_name(pcm));
    afbClient->verbose = 0;
    (void) asprintf(&afbClient->uid, "hook:%s:%d", afbClient->name, getpid());
    // Get PCM arguments from asoundrc

    printf("HookEntry handle=0x%x pcm=%s\n", afbClient, afbClient->name);
    snd_config_for_each(it, next, conf) {
        snd_config_t *node = snd_config_iterator_entry(it);
        const char *id;

        // ignore comment en empty lines
        if (snd_config_get_id(node, &id) < 0) continue;
        if (strcmp(id, "comment") == 0 || strcmp(id, "hint") == 0) continue;

        if (strcmp(id, "uri") == 0) {
            const char *uri;
            if (snd_config_get_string(node, &uri) < 0) {
                SNDERR("Invalid String for %s", id);
                goto OnErrorExit;
            }
            afbClient->uri=strdup(uri);
            continue;
        }

        if (strcmp(id, "verbose") == 0) {
            afbClient->verbose= snd_config_get_bool(node);
            if (afbClient->verbose < 0) {
                SNDERR("Invalid Boolean for %s", id);
                goto OnErrorExit;
            }
            continue;
        }

        if (strcmp(id, "synchronous") == 0) {
            afbClient->synchronous= snd_config_get_bool(node);
            if (afbClient->synchronous < 0) {
                SNDERR("Invalid Boolean for %s", id);
                goto OnErrorExit;
            }
            continue;
        }

        if (strcmp(id, "timeout") == 0) {
            if (snd_config_get_integer(node, &afbClient->timeout) < 0) {
                SNDERR("Invalid timeout Integer %s", id);
                goto OnErrorExit;
            }
            continue;
        }

        if (strcmp(id, "request") == 0) {
            afbClient->request =  malloc(MAX_API_CALL * sizeof(afbRequestT*));;
            int err= AlsaGetActions(node, afbClient->request , id);
            if (err) goto OnErrorExit;
            continue;
        }

        if (strcmp(id, "release") == 0) {
            afbClient->release =  malloc(MAX_API_CALL * sizeof(afbRequestT*));;
            int err= AlsaGetActions(node, afbClient->release, id);
            if (err) goto OnErrorExit;
            continue;
        }

        if (strcmp(id, "events") == 0) {
            afbClient->event=  malloc(MAX_API_CALL * sizeof(afbRequestT*));;
            int err= AlsaGetEvents(node, afbClient->event, id);
            if (err) goto OnErrorExit;
            continue;
        }
    }

    if (afbClient->verbose) fprintf(stdout, "\nAlsaHook Install Start PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);

    err = snd_pcm_hook_add(&h_close, afbClient->pcm, SND_PCM_HOOK_TYPE_CLOSE, AlsaCloseHook, afbClient);
    if (err < 0) goto OnErrorExit;
    afbClient->magic=MAGIC_HOOK;
    // launch call request and create a waiting mainloop thread
    err = LaunchCallRequest(afbClient, HOOK_INSTALL);
    if (err < 0) {
        fprintf (stderr, "PCM Fail to Get Authorisation\n");
        goto OnErrorExit;
    }

    // wait for all call request to return
    if (!afbClient->synchronous) sem_wait(&afbClient->semaphore);
    if (afbClient->errcount) {
        fprintf (stderr, "PCM Authorisation Deny from AAAA Controller (AGL Advanced Audio Agent)\n");
        goto OnErrorExit;
    }

    if (afbClient->verbose) fprintf(stdout, "\nAlsaHook Install Success PCM=%s URI=%s\n", afbClient->name, afbClient->uri);
    return 0;

OnErrorExit:
    fprintf(stderr, "\nAlsaPcmHook Plugin Policy Control Fail PCM=%s\n", afbClient->name);
    if (h_close)
        snd_pcm_hook_remove(h_close);

    return 0;
}