Extracted from Global afb-audio repo

3 files changed, 0 insertions, 667 deletions

diff --git a/Alsa-Plugin/Alsa-Policy-Hook/CMakeLists.txt b/Alsa-Plugin/Alsa-Policy-Hook/CMakeLists.txt
deleted file mode 100644
index 329b2ef..0000000
--- a/Alsa-Plugin/Alsa-Policy-Hook/CMakeLists.txt
+++ /dev/null
@@ -1,37 +0,0 @@
-###########################################################################
-# Copyright 2015, 2016, 2017 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.
-###########################################################################
-
-# Activate ALSA  dynamic build build mode get resolve "snd_dlsym_start"
-add_compile_options(-DPIC)
-
-PROJECT_TARGET_ADD(policy_hook_cb)
-
-    # Define targets
-    ADD_LIBRARY(${TARGET_NAME} MODULE PolicyHookCb.c)
-
-    # Alsa Plugin properties
-    SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
-	PREFIX ""
-        OUTPUT_NAME ${TARGET_NAME}
-    )
-
-    # Library dependencies (include updates automatically)
-    TARGET_LINK_LIBRARIES(${TARGET_NAME}
-        ${link_libraries}
-    )
-    install(TARGETS ${TARGET_NAME} LIBRARY DESTINATION lib)
diff --git a/Alsa-Plugin/Alsa-Policy-Hook/PolicyHookCb.c b/Alsa-Plugin/Alsa-Policy-Hook/PolicyHookCb.c
deleted file mode 100644
index 54fbe88..0000000
--- a/Alsa-Plugin/Alsa-Policy-Hook/PolicyHookCb.c
+++ /dev/null
@@ -1,554 +0,0 @@
-/*
- * 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 <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 <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__))
-void OnRequestCB(void* UNUSED_ARG(handle) , const char* UNUSED_ARG(api), const char* UNUSED_ARG(verb), struct afb_wsj1_msg*UNUSED_ARG(msg)) {}
-
-typedef struct {
-    const char *api;
-    const char *verb;
-    long timeout;
-    char *query;
-    size_t length;
-
-    sd_event_source *evtSource;
-    char *callIdTag;
-    void *afbClient;
-} afbRequestT;
-
-typedef struct {
-    const char *name;
-    int  signal;
-} afbEventT;
-
-typedef struct {
-    snd_pcm_t *pcm;
-    const char *uri;
-    struct afb_wsj1 *wsj1;
-    sd_event *sdLoop;
-    int verbose;
-    sem_t semaphore;
-    int count;
-    int error;
-    afbRequestT **request;
-    afbEventT **event;
-} 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 ping=%d\n", count++);
-        sd_event_run(afbClient->sdLoop, watchdog);
-    }
-
-    return NULL;
-}
-
-// lost connect with the AudioDaemon
-static void OnHangupCB(void *handle, struct afb_wsj1 *wsj1) {
-
-    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, struct afb_wsj1_msg *msg) {
-    afbClientT *afbClient = (afbClientT*) handle;
-    afbEventT **afbEvent = afbClient->event;
-    json_object *eventJ, *tmpJ, *dataJ;
-    const char *label;
-    int value, done, index;
-
-    eventJ = afb_wsj1_msg_object_j(msg);
-    done= json_object_object_get_ex(eventJ,"data", &dataJ);
-    if (!done) {
-        SNDERR ("PCM_HOOK: uri=%s empty event label", afbClient->uri);
-        goto OnErrorExit;
-    }
-
-    json_object_object_get_ex(dataJ,"signal", &tmpJ);
-    label=json_object_get_string(tmpJ);
-
-    json_object_object_get_ex(dataJ,"value", &tmpJ);
-    value=json_object_get_int(tmpJ);
-
-    for (index=0; afbEvent[index]!= NULL; index++) {
-        if (!strcmp(afbEvent[index]->name, label)) break;
-    }
-
-    if (!afbEvent[index] || !afbEvent[index]->signal) {
-        SNDERR ("PCM_HOOK: Unsupported uri=%s label=%s", afbClient->uri, label);
-        return;
-    }
-
-    // send signal to self process
-    kill (getpid(), afbEvent[index]->signal);
-
-    if (afbClient->verbose) printf("ON-EVENT label=%s signal=%d\n", label, value);
-    return;
-
-OnErrorExit:
-    SNDERR("ON-EVENT %s(%s)\n", event, afb_wsj1_msg_object_s(msg));
-    return;
-}
-
-// callback interface for wsj1
-static struct afb_wsj1_itf itf = {
-    .on_hangup = OnHangupCB,
-    .on_call = OnRequestCB,
-    .on_event = OnEventCB
-};
-
-void OnResponseCB(void *handle, struct afb_wsj1_msg *msg) {
-    afbRequestT *afbRequest= (afbRequestT*)handle;
-    afbClientT *afbClient=(afbClientT*)afbRequest->afbClient;
-
-    if (afbClient->verbose) printf("ON-RESPONSE call=%s response=%s\n", afbRequest->callIdTag, afb_wsj1_msg_object_s(msg));
-
-    // Cancel timeout for this request
-    sd_event_source_unref(afbRequest->evtSource);
-
-    if (! afb_wsj1_msg_is_reply_ok(msg)) goto OnErrorExit;
-
-    // When not more waiting call release semaphore
-    afbClient->count--;
-    if (afbClient->count == 0) {
-        if (afbClient->verbose) printf("ON-RESPONSE No More Waiting Request\n");
-        afbClient->error=0;
-        sem_post (&afbClient->semaphore);
-    }
-    return;
-
-OnErrorExit:
-    fprintf(stderr, "ON-RESPONSE ERROR call=%s response=%s\n", afbRequest->callIdTag, afb_wsj1_msg_object_s(msg));
-   afbClient->error=1;
-    sem_post (&afbClient->semaphore);
-}
-
-int OnTimeoutCB (sd_event_source* source, uint64_t timer, void* handle) {
-    afbClientT *afbClient= (afbClientT*)handle;
-
-    SNDERR("\nON-TIMEOUT Call Request Fail URI=%s\n", afbClient->uri);
-
-    // Close PCM and release waiting client
-    afbClient->error=1;
-    sem_post (&afbClient->semaphore);
-
-    return 0;
-}
-
-// Call AGL binder asynchronously by with a timeout
-static int CallWithTimeout(afbClientT *afbClient, afbRequestT *afbRequest, int count, hookActionT action) {
-    uint64_t usec;
-    int err;
-
-    // create a unique tag for request
-    (void) asprintf(&afbRequest->callIdTag, "%d:%s/%s", count, afbRequest->api, afbRequest->verb);
-
-    // 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+afbRequest->timeout*1000, 250, OnTimeoutCB, afbClient);
-
-    if (afbClient->verbose) printf("CALL-REQUEST api=%s/%s tag=%s\n", afbRequest->api, afbRequest->verb, afbRequest->callIdTag);
-
-    // on PCM close replace last '}' by CLOSING_MSG
-    if (action == HOOK_CLOSE) {
-        for (size_t index=afbRequest->length; index >0; index--) {
-            if (afbRequest->query[index] == '}') {
-                strcpy (&afbRequest->query[index], CLOSING_MSG);
-                break;
-            }
-        }
-    }
-
-    err = afb_wsj1_call_s(afbClient->wsj1, afbRequest->api, afbRequest->verb, afbRequest->query, OnResponseCB, afbRequest);
-    if (err) goto OnErrorExit;
-
-    // save client handle in request
-    afbRequest->afbClient = afbClient;
-    afbClient->count ++;
-
-    return 0;
-
-OnErrorExit:
-    return -1;
-}
-
-static int LaunchCallRequest(afbClientT *afbClient, hookActionT action) {
-
-    pthread_t tid;
-    int err, idx;
-    afbRequestT **afbRequest= afbClient->request;
-
-    if (action == HOOK_INSTALL) {
-        // 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_default(&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(&tid, NULL, &LoopInThread, afbClient);
-        if (err) goto OnErrorExit;
-
-        // connect the websocket wsj1 to the uri given by the first argument
-        afbClient->wsj1 = afb_ws_client_connect_wsj1(afbClient->sdLoop, afbClient->uri, &itf, afbClient);
-        if (afbClient->wsj1 == NULL) {
-            fprintf(stderr, "LaunchCallRequest: Connection to %s failed\n", afbClient->uri);
-            goto OnErrorExit;
-        }
-    }
-
-    // send call request to audio-agent asynchronously (respond with thread mainloop context)
-    for (idx = 0; afbRequest[idx] != NULL; idx++) {
-        err = CallWithTimeout(afbClient, afbRequest[idx], idx, action);
-        if (err) {
-            fprintf(stderr, "LaunchCallRequest: Fail call %s//%s/%s&%s", afbClient->uri, afbRequest[idx]->api, afbRequest[idx]->verb, afbRequest[idx]->query);
-            goto OnErrorExit;
-        }
-    }
-
-    // launch counter to keep track of waiting request call
-    afbClient->count=idx;
-
-    return 0;
-
-OnErrorExit:
-    return -1;
-}
-
-static int AlsaCloseHook(snd_pcm_hook_t *hook) {
-
-    afbClientT *afbClient = (afbClientT*) snd_pcm_hook_get_private (hook);
-
-    // launch call request and create a waiting mainloop thread
-    int err = LaunchCallRequest(afbClient, HOOK_CLOSE);
-    if (err < 0) {
-        fprintf (stderr, "PCM Fail to Enter Mainloop\n");
-        goto OnErrorExit;
-    }
-
-    // wait for all call request to return
-    sem_wait(&afbClient->semaphore);
-    if (afbClient->error) {
-        fprintf (stderr, "AlsaCloseHook: Audio Agent Fail to respond\n");
-        goto OnErrorExit;
-    }
-
-    if (afbClient->verbose) fprintf(stdout, "\nAlsaHook Close Success PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
-    return 0;
-
-OnErrorExit:
-    fprintf(stderr, "\nAlsaPcmHook Plugin Close Fail PCM=%s\n", snd_pcm_name(afbClient->pcm));
-    return 0;
-}
-
-// 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 = malloc(sizeof (afbClientT));
-    afbRequestT **afbRequest = malloc(MAX_API_CALL * sizeof(afbRequestT*));
-    afbEventT **afbEvent= malloc(MAX_EVT_CALL * sizeof(afbEventT*));
-    int err;
-
-    // start populating client handle
-    afbClient->pcm = pcm;
-    afbClient->verbose = 0;
-    afbClient->request = afbRequest;
-
-    // Get PCM arguments from asoundrc
-    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, "request") == 0) {
-            const char *callConf, *callLabel;
-            snd_config_type_t ctype;
-            snd_config_iterator_t currentCall, follow;
-            snd_config_t *itemConf;
-            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, &callLabel) < 0) continue;
-
-                // each clt should be a valid config compound
-                ctype = snd_config_get_type(ctlconfig);
-                if (ctype != SND_CONFIG_TYPE_COMPOUND) {
-                    snd_config_get_string(node, &callConf);
-                    SNDERR("Invalid call element for %s value=%s", callLabel, callConf);
-                    goto OnErrorExit;
-                }
-
-                // allocate an empty call request
-                afbRequest[callCount] = calloc(1, sizeof (afbRequestT));
-
-
-                err = snd_config_search(ctlconfig, "api", &itemConf);
-                if (!err) {
-                    const char *api;
-                    if (snd_config_get_string(itemConf, &api) < 0) {
-                        SNDERR("Invalid api string for %s", callLabel);
-                        goto OnErrorExit;
-                    }
-                    afbRequest[callCount]->api=strdup(api);
-                }
-
-                err = snd_config_search(ctlconfig, "verb", &itemConf);
-                if (!err) {
-                    const char *verb;
-                    if (snd_config_get_string(itemConf, &verb) < 0) {
-                        SNDERR("Invalid verb string %s", id);
-                        goto OnErrorExit;
-                    }
-                    afbRequest[callCount]->verb=strdup(verb);
-                }
-
-                err = snd_config_search(ctlconfig, "timeout", &itemConf);
-                if (!err) {
-                    if (snd_config_get_integer(itemConf, &afbRequest[callCount]->timeout) < 0) {
-                        SNDERR("Invalid timeout Integer %s", id);
-                        goto OnErrorExit;
-                    }
-                }
-
-                err = snd_config_search(ctlconfig, "query", &itemConf);
-                if (!err) {
-                    const char *query;
-                    if (snd_config_get_string(itemConf, &query) < 0) {
-                        SNDERR("Invalid args string %s", id);
-                        goto OnErrorExit;
-                    }
-                    // reserve enough space to ad closing message
-                    afbRequest[callCount]->length= strlen(query);
-                    afbRequest[callCount]->query = malloc (afbRequest[callCount]->length+strlen(CLOSING_MSG)+1);
-                    strcpy (afbRequest[callCount]->query, query);
-
-                    // cleanup string for json_tokener
-                    for (int idx = 0; query[idx] != '\0'; idx++) {
-                        if (query[idx] == '\'') afbRequest[callCount]->query[idx] = '"';
-                        else afbRequest[callCount]->query[idx] = query[idx];
-                    }
-                    json_object *queryJ = json_tokener_parse(afbRequest[callCount]->query);
-                    if (!queryJ) {
-                        SNDERR("Invalid Json %s args=%s should be args=\"{'tok1':'val1', 'tok2':'val2'}\" ", id, afbRequest[callCount]->query);
-                        goto OnErrorExit;
-                    }
-                }
-
-                // Simple check on call request validity
-                if (!afbRequest[callCount]->query)   afbRequest[callCount]->query= "";
-                if (!afbRequest[callCount]->timeout) afbRequest[callCount]->timeout=REQUEST_DEFAULT_TIMEOUT ;
-                if (!afbRequest[callCount]->verb || !afbRequest[callCount]->api) {
-                    SNDERR("Missing api/verb %s in asoundrc", callLabel);
-                    goto OnErrorExit;
-                }
-
-                // move to next call if any
-                callCount ++;
-                if (callCount == MAX_API_CALL) {
-                    SNDERR("Too Many call MAX_API_CALL=%d", MAX_API_CALL);
-                    goto OnErrorExit;
-                }
-                afbRequest[callCount]=NULL; // afbRequest array is NULL terminated
-
-            }
-            continue;
-        }
-        if (strcmp(id, "event") == 0) {
-            const char *callConf, *callLabel;
-            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);
-                long sigval;
-
-                // ignore empty line
-                if (snd_config_get_id(ctlconfig, &callLabel) < 0) continue;
-
-                // each clt should be a valid config compound
-                ctype = snd_config_get_type(ctlconfig);
-                if (ctype != SND_CONFIG_TYPE_INTEGER) {
-                    snd_config_get_string(ctlconfig, &callConf);
-                    SNDERR("Invalid signal number for %s value=%s", callLabel, callConf);
-                    goto OnErrorExit;
-                }
-
-                // allocate an empty call request
-                snd_config_get_integer(ctlconfig, &sigval);
-                afbEvent[callCount] = calloc(1, sizeof (afbEventT));
-                afbEvent[callCount]->name=strdup(callLabel);
-                afbEvent[callCount]->signal= (int)sigval;
-
-                // 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
-
-            }
-            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;
-
-    // launch call request and create a waiting mainloop thread
-    err = LaunchCallRequest(afbClient, HOOK_INSTALL);
-    if (err < 0) {
-        fprintf (stderr, "PCM Fail to Enter Mainloop\n");
-        goto OnErrorExit;
-    }
-
-    // wait for all call request to return
-    sem_wait(&afbClient->semaphore);
-    if (afbClient->error) {
-        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", snd_pcm_name(afbClient->pcm), afbClient->uri);
-    return 0;
-
-OnErrorExit:
-    fprintf(stderr, "\nAlsaPcmHook Plugin Install Fail PCM=%s\n", snd_pcm_name(pcm));
-    if (h_close)
-        snd_pcm_hook_remove(h_close);
-
-    return -EINVAL;
-}
-
diff --git a/Alsa-Plugin/Alsa-Policy-Hook/README.md b/Alsa-Plugin/Alsa-Policy-Hook/README.md
deleted file mode 100644
index 20186db..0000000
--- a/Alsa-Plugin/Alsa-Policy-Hook/README.md
+++ /dev/null
@@ -1,76 +0,0 @@
-Alsa-Hook-Plugin
-
-Object: Provide a Hook on Alsa PCM to check permission again AGL Advance Audio Agent
-Status: Release Candidate
-Author: Fulup Ar Foll fulup@iot.bzh
-Date  : August-2017
-
-Functionalities:
- - Execute a set of websocket RPC request again AGL binders to allow/deny access
- - Keep websocket open in an idepandant thread on order to monitor event receive from AGL audio agent
-
-Installation
- - Alsaplugins are typically search in /usr/share/alsa-lib. Nevertheless a full path might be given
- - This plugin implement a hook on a slave PCM. Typically this slave PCM is a dedicated virtual channel (eg: navigation, emergency,...)
- - Config should be place in ~/.asoundrc (see config sample in PROJECT_ROOT/conf.d/alsa)
-
-Test
- - Install a full .asoundrc from conf.d/project/alsa.d
- - speaker-test -DMyNavigationHook -c2 -twav
-
-Config
-```
-# Define sharelib location and entry point
-# -----------------------------------------
-pcm_hook_type.MyHookPlugin {
-    install "AlsaInstallHook"
-    lib "/home/fulup/Workspace/AGL-AppFW/audio-bindings-dev/build/Alsa-Plugin/Alsa-Hook-Callback/alsa_hook_cb.so"
-}
-
-# Create PCM HOOK with corresponding request calls to AGL Audio Agent
-# --------------------------------------------------------------------
-pcm.MyNavigationHook {
-    type hooks
-    slave.pcm "MyMixerPCM"
-
-    # Defined used hook sharelib and provide arguments/config to install func
-    hooks.0 {
-        type "MyHookPlugin"
-        hook_args {
-            verbose true # print few log messages (default false);
-
-            # Every Call should return OK in order PCM to open (default timeout 100ms)
-            uri   "ws://localhost:1234/api?token='audio-agent-token'"
-            request {
-                # Request autorisation to write on navigation
-                navigation-ctl {
-                    api   "control"
-                    verb  "dispatch"
-                    args   "{'target':'navigation', 'args':{'device':'Jabra SOLEMATE v1.34.0'}}"
-                }
-                # subscribe to Audio Agent Event map them to signal
-                subscribe-evt {
-                    api   "control"
-                    verb  "monitor"
-                }
-            }
-            # map event reception to self generated signal
-            event {
-                pause  30
-                resume 31
-                stop   3
-            }
-        }
-    }
-}
-
-```
-
-NOTE:
-
-* Hook plugin is loaded by Alsa libasound within player context. It inherits client process attributes, as UID/GID or
-the SMACK label on AGL. This smack label is tested by AGL security framework when requested a call on the audio-agent binder.
-As a result the call will only succeed it the permission attached the application in Cynara matches.
-
-* Hook plugin keep a connection with the Audio-Agent until PCM is closed by the application. This connection allow the
-Audio-Agent to send events. eg: pause, quit, mute, ...
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