bluez5: backend-native: handle multiple commands in RFCOMM input

Do relaxed parsing of RFCOMM commands for AG & HF roles, allowing
multiple commands in same buffer.

Use same parser code for all HFP/HSP AG/HF. Parse input in relaxed way,
as some devices emit spurious \n

spa/plugins/bluez5/backend-native.c

@@ -496,19 +496,19 @@ static bool rfcomm_hsp_hs(struct rfcomm *rfcomm, char* buf)
 	 *   or when the gain is changed on the AG side.
 	 * RING: Sent by AG to HS to notify of an incoming call. It can safely be ignored because
 	 *   it does not expect a reply. */
-	if (sscanf(buf, "\r\n+VGS=%d\r\n", &gain) == 1) {
+	if (sscanf(buf, "+VGS=%d", &gain) == 1) {
 		if (gain <= SPA_BT_VOLUME_HS_MAX) {
 			rfcomm_emit_volume_changed(rfcomm, SPA_BT_VOLUME_ID_RX, gain);
 		} else {
 			spa_log_debug(backend->log, "RFCOMM receive unsupported VGS gain: %s", buf);
 		}
-	} else if (sscanf(buf, "\r\n+VGM=%d\r\n", &gain) == 1) {
+	} else if (sscanf(buf, "+VGM=%d", &gain) == 1) {
 		if (gain <= SPA_BT_VOLUME_HS_MAX) {
 			rfcomm_emit_volume_changed(rfcomm, SPA_BT_VOLUME_ID_TX, gain);
 		} else {
 			spa_log_debug(backend->log, "RFCOMM receive unsupported VGM gain: %s", buf);
 		}
-	} else if (spa_strstartswith(buf, "\r\nOK\r\n")) {
+	} else if (spa_streq(buf, "OK")) {
 		if (rfcomm->hs_state == hsp_hs_init2) {
 			if (rfcomm_send_volume_cmd(rfcomm, SPA_BT_VOLUME_ID_RX))
 				rfcomm->hs_state = hsp_hs_vgs;
@@ -777,12 +777,6 @@ static bool rfcomm_hfp_ag(struct rfcomm *rfcomm, char* buf)
 	int xapl_product;
 	int xapl_features;
 
-	spa_debug_log_mem(backend->log, SPA_LOG_LEVEL_DEBUG, 2, buf, strlen(buf));
-
-	/* Some devices send initial \n: be permissive */
-	while (*buf == '\n')
-		++buf;
-
 	if (sscanf(buf, "AT+BRSF=%u", &features) == 1) {
 		unsigned int ag_features = SPA_BT_HFP_AG_FEATURE_NONE;
 
@@ -884,7 +878,7 @@ static bool rfcomm_hfp_ag(struct rfcomm *rfcomm, char* buf)
 				rfcomm_emit_volume_changed(rfcomm, -1, SPA_BT_VOLUME_INVALID);
 			}
 		}
-	} else if (spa_streq(buf, "\r")) {
+	} else if (spa_streq(buf, "")) {
 		/* No commands, reply OK (ITU-T Rec. V.250 Sec. 5.2.1 & 5.6) */
 		rfcomm_send_reply(rfcomm, "OK");
 	} else if (!rfcomm->slc_configured) {
@@ -1178,13 +1172,11 @@ next_indicator:
 	return true;
 }
 
-static bool rfcomm_hfp_hf(struct rfcomm *rfcomm, char* buf)
+static bool rfcomm_hfp_hf(struct rfcomm *rfcomm, char* token)
 {
 	struct impl *backend = rfcomm->backend;
 	unsigned int features, gain, selected_codec, indicator, value;
-	char* token;
 
-	while ((token = strsep(&buf, "\r\n"))) {
 	if (sscanf(token, "+BRSF:%u", &features) == 1) {
 		if (((features & (SPA_BT_HFP_AG_FEATURE_CODEC_NEGOTIATION)) != 0) &&
 				rfcomm->msbc_supported_by_hfp)
@@ -1320,13 +1312,41 @@ static bool rfcomm_hfp_hf(struct rfcomm *rfcomm, char* buf)
 			break;
 		}
 	}
-	}
 
 	return true;
 }
 
 #endif
 
+static void rfcomm_process_events(struct rfcomm *rfcomm, char *buf, bool ag, bool (*handler)(struct rfcomm *, char *))
+{
+	struct impl *backend = rfcomm->backend;
+	char *token;
+
+	/* Relaxed parsing of both <COMMAND>\r (AG) and \r\n<REPLY>\r\n (HF) */
+
+	while ((token = strsep(&buf, "\r"))) {
+		size_t len;
+
+		/* Skip leading and trailing \n */
+		while (*token == '\n')
+			++token;
+		for (len = strlen(token); len > 0 && token[len - 1] == '\n'; --len)
+			token[len - 1] = '\0';
+
+		/* Skip empty (only last one if AG) */
+		if (*token == '\0' && (buf == NULL || !ag))
+			continue;
+
+		spa_log_debug(backend->log, "RFCOMM event: %s", token);
+
+		if (!handler(rfcomm, token)) {
+			spa_log_debug(backend->log, "RFCOMM received unsupported event: %s", token);
+			rfcomm_send_error(rfcomm, CMEE_OPERATION_NOT_SUPPORTED);
+		}
+	}
+}
+
 static void rfcomm_event(struct spa_source *source)
 {
 	struct rfcomm *rfcomm = source->data;
@@ -1341,41 +1361,37 @@ static void rfcomm_event(struct spa_source *source)
 	if (source->rmask & SPA_IO_IN) {
 		char buf[512];
 		ssize_t len;
-		bool res = false;
 
-		len = read(source->fd, buf, 511);
+		len = read(source->fd, buf, sizeof(buf) - 1);
 		if (len < 0) {
 			spa_log_error(backend->log, "RFCOMM read error: %s", strerror(errno));
 			return;
 		}
 		buf[len] = 0;
+
 		spa_log_debug(backend->log, "RFCOMM << %s", buf);
+		spa_debug_log_mem(backend->log, SPA_LOG_LEVEL_DEBUG, 2, buf, strlen(buf));
 
 		switch (rfcomm->profile) {
 #ifdef HAVE_BLUEZ_5_BACKEND_HSP_NATIVE
 		case SPA_BT_PROFILE_HSP_HS:
-			res = rfcomm_hsp_ag(rfcomm, buf);
+			rfcomm_process_events(rfcomm, buf, true, rfcomm_hsp_ag);
 			break;
 		case SPA_BT_PROFILE_HSP_AG:
-			res = rfcomm_hsp_hs(rfcomm, buf);
+			rfcomm_process_events(rfcomm, buf, false, rfcomm_hsp_hs);
 			break;
 #endif
 #ifdef HAVE_BLUEZ_5_BACKEND_HFP_NATIVE
 		case SPA_BT_PROFILE_HFP_HF:
-			res = rfcomm_hfp_ag(rfcomm, buf);
+			rfcomm_process_events(rfcomm, buf, true, rfcomm_hfp_ag);
 			break;
 		case SPA_BT_PROFILE_HFP_AG:
-			res = rfcomm_hfp_hf(rfcomm, buf);
+			rfcomm_process_events(rfcomm, buf, false, rfcomm_hfp_hf);
 			break;
 #endif
 		default:
 			break;
 		}
-
-		if (!res) {
-			spa_log_debug(backend->log, "RFCOMM received unsupported command: %s", buf);
-			rfcomm_send_error(rfcomm, CMEE_OPERATION_NOT_SUPPORTED);
-		}
 	}
 }