From: Melissa LeBlanc-Williams <melissa@adafruit.com>
Date: Sun, 1 Nov 2020 17:47:38 +0000 (-0700)
Subject: Merge pull request #359 from michaellass/remove_malicious_timeout
X-Git-Tag: 5.7.0~2
X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/commitdiff_plain/b14047931521d98f1ac87c492ae54251c893ae07?hp=75ee720cb27c78b0cea76d2b52c4f3d26cd331b0

Merge pull request #359 from michaellass/remove_malicious_timeout

Do not prematurely stop waiting for an answer from the message queue
---

diff --git a/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py b/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py
index aef942a..19dc98f 100644
--- a/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py
+++ b/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py
@@ -70,26 +70,29 @@ class PulseIn:
         # wait for it to start up
         if DEBUG:
             print("Waiting for startup success message from subprocess")
-        message = self._wait_receive_msg()
+        message = self._wait_receive_msg(timeout=0.25)
         if message[0] != b"!":
             raise RuntimeError("Could not establish message queue with subprocess")
         self._paused = False
 
     # pylint: disable=redefined-builtin
-    def _wait_receive_msg(self, timeout=0.25, type=2):
+    def _wait_receive_msg(self, timeout=0, type=2):
         """Internal helper that will wait for new messages of a given type,
         and throw an exception on timeout"""
-        stamp = time.monotonic()
-        while (time.monotonic() - stamp) < timeout:
-            try:
-                message = self._mq.receive(block=False, type=type)
-                return message
-            except sysv_ipc.BusyError:
-                time.sleep(0.001)  # wait a bit then retry!
-        # uh-oh timed out
-        raise RuntimeError(
-            "Timed out waiting for PulseIn message. Make sure libgpiod is installed."
-        )
+        if timeout > 0:
+            stamp = time.monotonic()
+            while (time.monotonic() - stamp) < timeout:
+                try:
+                    message = self._mq.receive(block=False, type=type)
+                    return message
+                except sysv_ipc.BusyError:
+                    time.sleep(0.001)  # wait a bit then retry!
+            # uh-oh timed out
+            raise RuntimeError(
+                "Timed out waiting for PulseIn message. Make sure libgpiod is installed."
+            )
+        message = self._mq.receive(block=True, type=type)
+        return message
 
     # pylint: enable=redefined-builtin