Implement getSerialNumber (based on BT MAC)

libs/core/linux.cpp

@@ -221,10 +221,6 @@ int current_time_ms() {
     return currTime() - startTime;
 }
 
-int getSerialNumber() {
-    return 42; // TODO
-}
-
 void disposeThread(Thread *t) {
     if (allThreads == t) {
         allThreads = t->next;

libs/core/pxt.json

@@ -10,6 +10,7 @@
         "linux.cpp",
         "mmap.cpp",
         "control.cpp",
+        "serialnumber.cpp",
         "buttons.ts",
         "png.cpp",
         "screen.cpp",

libs/core/serialnumber.cpp

@@ -0,0 +1,78 @@
+#include "pxt.h"
+
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#define BTPROTO_HCI	1
+#define HCIGETDEVLIST	_IOR('H', 210, int)
+#define HCIGETDEVINFO	_IOR('H', 211, int)
+
+struct hci_dev_info {
+	uint16_t dev_id;
+	char  name[8];
+	uint8_t bdaddr[6];
+    uint32_t padding[32];
+};
+
+struct hci_dev_req {
+	uint16_t  dev_id;
+	uint32_t  dev_opt;
+};
+
+struct hci_dev_list_req {
+	uint16_t  dev_num;
+	hci_dev_req dev_req[2];
+};
+
+
+static uint32_t bt_addr() {
+    uint32_t res = 0;
+
+    int fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
+    if (fd < 0) {
+        DMESG("Can't open HCI socket");
+        return res;
+    }
+
+    hci_dev_list_req dl;
+    dl.dev_num = 1;
+
+    if (ioctl(fd, HCIGETDEVLIST, (void *)&dl) < 0) {
+        DMESG("Failed to get HCI device list");
+        goto done;
+    }
+
+    hci_dev_info di;
+    di.dev_id = dl.dev_req[0].dev_id;
+
+    if (ioctl(fd, HCIGETDEVINFO, (void *)&di) < 0) {
+        DMESG("Failed to get HCI device list");
+        goto done;
+    }
+
+    memcpy(&res, di.bdaddr, 4);
+    res *= 0x1000193;
+    res += di.bdaddr[4];
+    res *= 0x1000193;
+    res += di.bdaddr[5];
+
+done:
+    close(fd);
+    return res;
+}
+
+namespace pxt {
+
+int getSerialNumber() {
+    static int serial;
+
+    if (serial != 0)
+        return serial;
+
+    serial = bt_addr() & 0x7fffffff;
+
+    return serial;
+}
+
+} // namespace pxt