summaryrefslogtreecommitdiffstats
path: root/Alsa-Plugin/Alsa-Policy-Hook/AlsaHookCb.c
blob: 2675805be97c5b2aabc50050de57f66c9fb62c52 (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
/*
 * 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

// Currently not implemented
#define UNUSED(x) UNUSED_ ## x __attribute__((__unused__))
#define UNUSED_FUNCTION(x) __attribute__((__unused__)) UNUSED_ ## x
void OnRequestCB(void* UNUSED(handle) , const char* UNUSED(api), const char* UNUSED(verb), struct afb_wsj1_msg*UNUSED(msg)) {}

    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;
} afbClientT;

typedef struct {
    const char *api;
    const char *verb;
    long timeout;
    char *query;
    
    sd_event_source *evtSource;
    char *callIdTag;
    afbClientT *afbClient;
} afbRequestT;

static void *LoopInThread(void *handle) {
    afbClientT *afbClient = (afbClientT*) handle;
    int count=0;
    int watchdog= 60 *1000000;

    /* loop until end */
    for (;;) {
        
        if (afbClient->verbose) printf("ON-MAINLOOP Active count=%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;
    snd_pcm_close (afbClient->pcm);

    SNDERR("(Hoops) Lost Connection to %s", afbClient->uri);
    exit(0);
}

void OnEventCB(void *handle, const char *event, struct afb_wsj1_msg *msg) {
    afbClientT *afbClient = (afbClientT*) handle;
    int err;
    
    printf("ON-EVENT %s(%s)\n", event, afb_wsj1_msg_object_s(msg));
    
    // pause PCM until request call succeed    
    err = snd_pcm_pause (afbClient->pcm, 1);
    if (err < 0) {
        fprintf (stderr, "PCM Fail to pause\n");
        goto OnErrorExit;
    }
    
    // wait on a semaphore until request return or timeout
    err = snd_pcm_pause (afbClient->pcm, 0);
    if (err < 0) {
        fprintf (stderr, "PCM Fail to resume\n");
        goto OnErrorExit;
    }
    
OnErrorExit:
    return;
    
}

// callback interface for wsj1
static struct afb_wsj1_itf itf = {
    .on_hangup = OnHangupCB,
    .on_call = OnRequestCB,
    .on_event = OnEventCB
};

void OnAbortPcm (afbClientT *afbClient) {
    printf("ON-ABORT-PCM PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
    snd_pcm_close (afbClient->pcm);
}

void OnResponseCB(void *handle, struct afb_wsj1_msg *msg) {
    afbRequestT *afbRequest= (afbRequestT*)handle;

    if (afbRequest->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)) {
        fprintf(stderr, "ON-RESPONSE ERROR call=%s response=%s\n", afbRequest->callIdTag, afb_wsj1_msg_object_s(msg));
        OnAbortPcm (afbRequest->afbClient);
    } 
    
    // When not more waiting call release semaphore
    afbRequest->afbClient->count--;
    if (afbRequest->afbClient->count == 0) {
        if (afbRequest->afbClient->verbose) printf("ON-RESPONSE No More Waiting Request\n");
        afbRequest->afbClient->error=0;
        sem_post (&afbRequest->afbClient->semaphore);
    }
}

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

    fprintf(stderr, "ON-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) {
    uint64_t usec;
    int err;

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

    err = afb_wsj1_call_s(afbClient->wsj1, afbRequest->api, afbRequest->verb, afbRequest->query, OnResponseCB, afbRequest);
    if (err) goto OnErrorExit;
    
    // 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);

    // save client handle in request
    afbRequest->afbClient = afbClient;
    afbClient->count ++;
    
    return 0;
    
OnErrorExit:
    return -1;
}

static int LaunchCallRequest(afbClientT *afbClient, afbRequestT **afbRequest) {

    pthread_t tid;
    int err, idx;

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

    // start a thread with a mainloop to monitor Audio-Agent
    err = pthread_create(&tid, NULL, &LoopInThread, afbClient);
    if (err) goto OnErrorExit;
    
    return 0;

OnErrorExit:
    return -1;
}

static int AlsaCloseHook(snd_pcm_hook_t *hook) {

    afbClientT *afbClient = (afbClientT*) snd_pcm_hook_get_private (hook);
    
    if (afbClient->verbose) fprintf(stdout, "\nAlsaCloseHook pcm=%s uri=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
    return 0;
}

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

    // start populating client handle
    afbClient->pcm = pcm;
    afbClient->verbose = 0;

    
    // 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) {
            if (snd_config_get_string(node, &afbClient->uri) < 0) {
                SNDERR("Invalid String for %s", id);
                goto OnErrorExit;
            }
            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", callLabel);
                    goto OnErrorExit;
                }

                // allocate an empty call request
                afbRequest[callCount] = malloc(sizeof (afbRequestT));
                afbRequest[callCount]->api=NULL;
                afbRequest[callCount]->verb=NULL;
                afbRequest[callCount]->query=NULL;


                err = snd_config_search(ctlconfig, "api", &itemConf);
                if (!err) {
                    if (snd_config_get_string(itemConf, &afbRequest[callCount]->api) < 0) {
                        SNDERR("Invalid api string for %s", callLabel);
                        goto OnErrorExit;
                    }
                }
                
                err = snd_config_search(ctlconfig, "verb", &itemConf);
                if (!err) {
                    if (snd_config_get_string(itemConf, &afbRequest[callCount]->verb) < 0) {
                        SNDERR("Invalid verb string %s", id);
                        goto OnErrorExit;
                    }
                }
                
                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 query string %s", id);
                        goto OnErrorExit;
                    }
                    // cleanup string for json_tokener
                    afbRequest[callCount]->query = strdup(query);
                    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(query);
                    if (!queryJ) {
                        SNDERR("Invalid Json %s query=%s format \"{'tok1':'val1', 'tok2':'val2'}\" ", id, query);
                        goto OnErrorExit;
                    }
                }
                
                // Simple check on call request validity
                if (!afbRequest[callCount]->query)   afbRequest[callCount]->query= "";
                if (!afbRequest[callCount]->timeout) afbRequest[callCount]->timeout=100;
                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 (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, afbRequest);
    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 from Audio Agent Refused\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(afbClient->pcm));
    if (h_close)
        snd_pcm_hook_remove(h_close);

    return -EINVAL;
}