From: Otto <otto.moerbeek@open-xchange.com>
Date: Mon, 8 Nov 2021 12:32:50 +0000 (+0100)
Subject: Use a global timeout for the various recv's we're doing to get a control message
X-Git-Tag: rec-4.6.0-beta1^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5fc89ddc7a74d3b88abcbe324fb85f45bc03d34d;p=thirdparty%2Fpdns.git

Use a global timeout for the various recv's we're doing to get a control message
---

diff --git a/pdns/rec_channel.cc b/pdns/rec_channel.cc
index b288abe832..41faffddb6 100644
--- a/pdns/rec_channel.cc
+++ b/pdns/rec_channel.cc
@@ -152,16 +152,30 @@ void RecursorControlChannel::send(int fd, const Answer& msg, unsigned int timeou
   }
 }
 
-RecursorControlChannel::Answer RecursorControlChannel::recv(int fd, unsigned int timeout)
+static void waitForRead(int fd, unsigned int timeout, time_t start)
 {
-  int ret = waitForData(fd, timeout, 0);
+  time_t elapsed = time(nullptr) - start;
+  if (elapsed >= timeout) {
+    throw PDNSException("Timeout waiting for control channel data");
+  }
+  int ret = waitForData(fd, timeout - elapsed, 0);
   if (ret == 0) {
-    throw PDNSException("Timeout waiting for answer from control channel");
+    throw PDNSException("Timeout waiting for control channel data");
   }
+}
+
+RecursorControlChannel::Answer RecursorControlChannel::recv(int fd, unsigned int timeout)
+{
+  // timeout covers the operation of all read ops combined
+  const time_t start = time(nullptr);
+
+  waitForRead(fd, timeout, start);
   int err;
   if (::recv(fd, &err, sizeof(err), 0) != sizeof(err)) {
     throw PDNSException("Unable to receive return status over control channel: " + stringerror());
   }
+
+  waitForRead(fd, timeout, start);
   size_t len;
   if (::recv(fd, &len, sizeof(len), 0) != sizeof(len)) {
     throw PDNSException("Unable to receive length over control channel: " + stringerror());
@@ -171,6 +185,7 @@ RecursorControlChannel::Answer RecursorControlChannel::recv(int fd, unsigned int
   str.reserve(len);
   while (str.length() < len) {
     char buffer[1024];
+    waitForRead(fd, timeout, start);
     size_t toRead = std::min(len - str.length(), sizeof(buffer));
     ssize_t recvd = ::recv(fd, buffer, toRead, 0);
     if (recvd <= 0) {