diff options
Diffstat (limited to 'hook-plugin')
| -rw-r--r-- | hook-plugin/CMakeLists.txt | 37 | ||||
| -rw-r--r-- | hook-plugin/PolicyHookCb.c | 560 | ||||
| -rw-r--r-- | hook-plugin/README.md | 77 |
3 files changed, 674 insertions, 0 deletions
diff --git a/hook-plugin/CMakeLists.txt b/hook-plugin/CMakeLists.txt new file mode 100644 index 0000000..329b2ef --- /dev/null +++ b/hook-plugin/CMakeLists.txt @@ -0,0 +1,37 @@ +########################################################################### +# 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/hook-plugin/PolicyHookCb.c b/hook-plugin/PolicyHookCb.c new file mode 100644 index 0000000..fdec61d --- /dev/null +++ b/hook-plugin/PolicyHookCb.c @@ -0,0 +1,560 @@ +/* + * 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 *openVerb; + const char *closeVerb; + 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; + const char * apiVerb; + int err; + + // create a unique tag for request + (void) asprintf(&afbRequest->callIdTag, "%d:%s/%s", count, afbRequest->api, afbRequest->openVerb); + + // 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); + + + // on PCM close replace last '}' by CLOSING_MSG + if (action == HOOK_CLOSE) apiVerb= afbRequest->closeVerb; + else apiVerb= afbRequest->openVerb; + + // release action is optional + if (apiVerb) { + if (afbClient->verbose) printf("CALL-REQUEST api=%s/%s tag=%s\n", afbRequest->api, apiVerb, afbRequest->callIdTag); + err = afb_wsj1_call_s(afbClient->wsj1, afbRequest->api, apiVerb, afbRequest->query, OnResponseCB, afbRequest); + if (err) goto OnErrorExit; + } + // save client handle in request + afbRequest->afbClient = afbClient; + afbClient->count ++; + + return 0; + +OnErrorExit: + fprintf(stderr, "LaunchCallRequest: Fail call %s//%s/%s&%s", afbClient->uri, afbRequest->api, apiVerb, afbRequest->query); + 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) 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: Notice exit before audio-4a response\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, "request", &itemConf); + if (!err) { + const char *verb; + if (snd_config_get_string(itemConf, &verb) < 0) { + SNDERR("Invalid open verb string %s", id); + goto OnErrorExit; + } + afbRequest[callCount]->openVerb=strdup(verb); + } + + err = snd_config_search(ctlconfig, "release", &itemConf); + if (!err) { + const char *verb; + if (snd_config_get_string(itemConf, &verb) < 0) { + SNDERR("Invalid close verb string %s", id); + goto OnErrorExit; + } + afbRequest[callCount]->closeVerb=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, "args", &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]->openVerb || !afbRequest[callCount]->api) { + SNDERR("Missing api/open(verb)/close(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/hook-plugin/README.md b/hook-plugin/README.md new file mode 100644 index 0000000..0472c7b --- /dev/null +++ b/hook-plugin/README.md @@ -0,0 +1,77 @@ +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 authorisation to write on navigation + navigation-ctl { + api "pol4a" + request "navigation-role" + release "navigation-role" + args "{'uid':'alsa-hook-navigation'}" + } + # subscribe to Audio Agent Event map them to signal + subscribe-evt { + api "pol4a" + verb "subscribe" + } + } + # 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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