Add verb to get PCM availability

Add verb to get PCM availability, this verb will return a boolean json.
PCM can be specified using two ways :
- card & device & subdevice & stream
- pcmName & stream

BUG-AGL: SPEC-2834

Change-Id: I176fdc261fa117906a2af069d3ddd07d5941904c
Signed-off-by: Jonathan Aillet <jonathan.aillet@iot.bzh>

3 files changed, 152 insertions, 1 deletions

diff --git a/alsa-binding/Alsa-ApiHat.c b/alsa-binding/Alsa-ApiHat.c
index 5575a9a..13c450c 100644
--- a/alsa-binding/Alsa-ApiHat.c
+++ b/alsa-binding/Alsa-ApiHat.c
@@ -42,6 +42,7 @@ static const afb_verb_t api_verbs[] = {
     /* VERB'S NAME          FUNCTION TO CALL  */
     { .verb = "ping", .callback = pingtest, .info="Ping Presence Check on API"},
     { .verb = "infoget", .callback = alsaGetInfo, .info="Return sound cards list"},
+    { .verb = "pcmready", .callback = alsaGetPcmAvailability, .info="Get Pcm availability"},
     { .verb = "ctlget", .callback = alsaGetCtls, .info="Get one or many control values"},
     { .verb = "ctlset", .callback = alsaSetCtls, .info="Set one control or more"},
     { .verb = "subscribe", .callback = alsaEvtSubscribe, .info="subscribe to alsa events"},
diff --git a/alsa-binding/Alsa-ApiHat.h b/alsa-binding/Alsa-ApiHat.h
index 21aaa61..35f96bb 100644
--- a/alsa-binding/Alsa-ApiHat.h
+++ b/alsa-binding/Alsa-ApiHat.h
@@ -103,8 +103,13 @@ PUBLIC queryModeE alsaGetModeFromQuery(json_object *queryJ);
 // AlseCoreSetGet exports
 PUBLIC int getCardNbFromCardPath(char *cardPath);
 PUBLIC json_object *getCardInfo(int card);
-PUBLIC int alsaGetSingleCtl (snd_ctl_t *ctlDev, snd_ctl_elem_id_t *elemId, ctlRequestT *ctlRequest, queryModeE queryMode);
 PUBLIC void alsaGetInfo (afb_req_t request);
+PUBLIC int alsaGetPcmProcStatusFd(unsigned int card, unsigned int device, unsigned int subdevice, snd_pcm_stream_t pcmStream);
+PUBLIC int alsaIsPcmAvailableUsingPcmProcFd(int fd);
+PUBLIC int alsaIsPcmAvailableUsingId(unsigned int card, unsigned int device, unsigned int subdevice, snd_pcm_stream_t pcmStream);
+PUBLIC int alsaIsPcmAvailableUsingPcmName(char *pcmName, snd_pcm_stream_t pcmStream);
+PUBLIC void alsaGetPcmAvailability(afb_req_t request);
+PUBLIC int alsaGetSingleCtl (snd_ctl_t *ctlDev, snd_ctl_elem_id_t *elemId, ctlRequestT *ctlRequest, queryModeE queryMode);
 PUBLIC void alsaGetCtls(afb_req_t request);
 PUBLIC void alsaSetCtls(afb_req_t request);
 
diff --git a/alsa-binding/Alsa-SetGet.c b/alsa-binding/Alsa-SetGet.c
index 78ac7e9..af96b86 100644
--- a/alsa-binding/Alsa-SetGet.c
+++ b/alsa-binding/Alsa-SetGet.c
@@ -37,6 +37,9 @@
 #define _IOR_HACKED(type,nr,size)       _IOC(_IOC_READ,(type),(nr),size)
 #define SNDRV_CTL_IOCTL_CARD_INFO(size) _IOR_HACKED('U', 0x01, size)
 
+#define PCM_PROC_STATUS_STRING              "/proc/asound/card%i/pcm%i%c/sub%i/status"
+#define PCM_PROC_AVAILABLE_PCM_STRING       "closed"
+#define PCM_PROC_AVAILABLE_PCM_STRING_SIZE  (sizeof(PCM_PROC_AVAILABLE_PCM_STRING) - 1)
 
 PUBLIC void NumidsListParse(ActionSetGetT action, controlQueryValuesT *queryControlValues, ctlRequestT *ctlRequest) {
     int length;
@@ -999,6 +1002,148 @@ PUBLIC void alsaGetInfo(afb_req_t request) {
     afb_req_success(request, toReturnJ, "Found requested sound card(s) properties are available in returned Json");
 }
 
+STATIC char *getAlsaPcmStatusFilePath(unsigned int card, unsigned int device, unsigned int subdevice, snd_pcm_stream_t stream)
+{
+    int err;
+    char *pcmStatusFilePath = NULL;
+
+    if(card > MAX_SND_CARD || device > MAX_CARD_DEVICES || subdevice > MAX_DEVICE_SUBDEVICES)
+        return NULL;
+
+    err = asprintf(&pcmStatusFilePath, PCM_PROC_STATUS_STRING, card, device, (stream == SND_PCM_STREAM_PLAYBACK) ? 'p' : 'c', subdevice);
+    if(err <= 0)
+        return NULL;
+
+    return pcmStatusFilePath;
+}
+
+PUBLIC int alsaGetPcmProcStatusFd(unsigned int card, unsigned int device, unsigned int subdevice, snd_pcm_stream_t pcmStream)
+{
+    int fd;
+
+    char *pcmStatusFilePath = NULL;
+
+    if(card > MAX_SND_CARD || device > MAX_CARD_DEVICES || subdevice > MAX_DEVICE_SUBDEVICES)
+        return -1;
+
+    pcmStatusFilePath = getAlsaPcmStatusFilePath(card, device, subdevice, pcmStream);
+    if(! pcmStatusFilePath)
+        return -2;
+
+    fd = open(pcmStatusFilePath, O_RDONLY | O_NONBLOCK);
+    if(fd < 0)
+        return -3;
+
+    return fd;
+}
+
+PUBLIC int alsaIsPcmAvailableUsingPcmProcFd(int fd)
+{
+    char statusFileContent[PCM_PROC_AVAILABLE_PCM_STRING_SIZE];
+
+    if(fd < 0)
+        return -1;
+
+    if(lseek(fd, 0, SEEK_SET) < 0)
+        return -2;
+
+    if(read(fd, statusFileContent, PCM_PROC_AVAILABLE_PCM_STRING_SIZE) < 0)
+        return -3;
+
+    if(! strncmp(statusFileContent, PCM_PROC_AVAILABLE_PCM_STRING, PCM_PROC_AVAILABLE_PCM_STRING_SIZE))
+        return 1;
+
+    return 0;
+}
+
+PUBLIC int alsaIsPcmAvailableUsingId(unsigned int card, unsigned int device, unsigned int subdevice, snd_pcm_stream_t pcmStream)
+{
+    int fd, pcmIsAvailable;
+
+    if(card > MAX_SND_CARD || device > MAX_CARD_DEVICES || subdevice > MAX_DEVICE_SUBDEVICES)
+        return -1;
+
+    fd = alsaGetPcmProcStatusFd(card, device, subdevice, pcmStream);
+    if(fd < 0)
+        return -2;
+
+    pcmIsAvailable = alsaIsPcmAvailableUsingPcmProcFd(fd);
+    if(pcmIsAvailable < 0) {
+        close(fd);
+        return -3;
+    }
+
+    close(fd);
+    return pcmIsAvailable;
+}
+
+PUBLIC int alsaIsPcmAvailableUsingPcmName(char *pcmName, snd_pcm_stream_t pcmStream)
+{
+    int card = NO_CARD_SELECTED, device = NO_DEVICE_SELECTED, subdevice = NO_SUBDEVICE_SELECTED, pcmIsAvailable;
+
+    if(! pcmName)
+        return -1;
+
+    if(sscanf(pcmName, "hw:%i,%i,%i", &card, &device, &subdevice) != 3)
+        return -2;
+
+    if(card < 0 || card > MAX_SND_CARD ||
+       device < 0 || device > MAX_CARD_DEVICES ||
+       subdevice < 0 || subdevice > MAX_DEVICE_SUBDEVICES)
+        return -3;
+
+    pcmIsAvailable = alsaIsPcmAvailableUsingId(card, device, subdevice, pcmStream);
+    if(pcmIsAvailable < 0)
+        return -4;
+
+    return pcmIsAvailable;
+}
+
+PUBLIC void alsaGetPcmAvailability(afb_req_t request)
+{
+    int wrapRet,
+        pcmIsAvailable,
+        card = NO_CARD_SELECTED,
+        device = NO_DEVICE_SELECTED,
+        subdevice = NO_SUBDEVICE_SELECTED;
+
+    char *pcmName = NULL;
+
+    snd_pcm_stream_t pcmStream;
+
+    json_object *queryJ;
+
+    queryJ = afb_req_json(request);
+    if(! queryJ) {
+        afb_req_fail(request, "invalid_request", "Request json is unavailable");
+        return;
+    }
+
+    wrapRet = wrap_json_unpack(queryJ,
+                               "{s?:i, s?:i, s?:i, s?:s, s:i !}",
+                               "card", &card,
+                               "device", &device,
+                               "subdevice", &subdevice,
+                               "name", &pcmName,
+                               "stream", &pcmStream);
+    if(wrapRet || (! pcmName && (card == NO_CARD_SELECTED || device == NO_DEVICE_SELECTED || subdevice == NO_SUBDEVICE_SELECTED))) {
+        afb_req_fail_f(request, "invalid_request", "Request json is invalid (%s)", json_object_get_string(queryJ));
+        return;
+    }
+
+    if(! pcmName)
+        pcmIsAvailable = alsaIsPcmAvailableUsingId(card, device, subdevice, pcmStream);
+    else
+        pcmIsAvailable = alsaIsPcmAvailableUsingPcmName(pcmName, pcmStream);
+
+    if(pcmIsAvailable < 0) {
+        afb_req_fail_f(request, "invalid_pcm", "Pcm specified in json is invalid (%s)", json_object_get_string(queryJ));
+        return;
+    }
+
+    afb_req_success(request, json_object_new_boolean(pcmIsAvailable), NULL);
+}
+
 // pack Alsa element's ACL into a JSON object
 
 STATIC json_object *getControlAcl(snd_ctl_elem_info_t *info) {