boardd: check do_exit in usb_retry_connect (#20007)

selfdrive/boardd/boardd.cc

@@ -36,7 +36,7 @@
 #define SATURATE_IL 1600
 #define NIBBLE_TO_HEX(n) ((n) < 10 ? (n) + '0' : ((n) - 10) + 'a')
 
-Panda * panda = NULL;
+Panda * panda = nullptr;
 std::atomic<bool> safety_setter_thread_running(false);
 std::atomic<bool> ignition(false);
 
@@ -121,7 +121,7 @@ bool usb_connect() {
 
   std::unique_ptr<Panda> tmp_panda;
   try {
-    assert(panda == NULL);
+    assert(panda == nullptr);
     tmp_panda = std::make_unique<Panda>();
   } catch (std::exception &e) {
     return false;
@@ -180,10 +180,13 @@ bool usb_connect() {
 }
 
 // must be called before threads or with mutex
-void usb_retry_connect() {
+static bool usb_retry_connect() {
   LOGW("attempting to connect");
-  while (!usb_connect()) { util::sleep_for(100); }
-  LOGW("connected to board");
+  while (!do_exit && !usb_connect()) { util::sleep_for(100); }
+  if (panda) {
+    LOGW("connected to board");
+  }
+  return !do_exit;
 }
 
 void can_recv(PubMaster &pm) {
@@ -523,16 +526,16 @@ int main() {
     threads.push_back(std::thread(can_health_thread, getenv("STARTED") != nullptr));
 
     // connect to the board
-    usb_retry_connect();
-
-    threads.push_back(std::thread(can_send_thread, getenv("FAKESEND") != nullptr));
-    threads.push_back(std::thread(can_recv_thread));
-    threads.push_back(std::thread(hardware_control_thread));
-    threads.push_back(std::thread(pigeon_thread));
+    if (usb_retry_connect()) {
+      threads.push_back(std::thread(can_send_thread, getenv("FAKESEND") != nullptr));
+      threads.push_back(std::thread(can_recv_thread));
+      threads.push_back(std::thread(hardware_control_thread));
+      threads.push_back(std::thread(pigeon_thread));
+    }
 
     for (auto &t : threads) t.join();
 
     delete panda;
-    panda = NULL;
+    panda = nullptr;
   }
 }