ignoreSignalsInThread()

eth/common/utils.nim

@@ -1,4 +1,14 @@
-import nimcrypto/hash, hashes, stew/byteutils, eth_types, metrics
+# Copyright (c) 2019-2020 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
+# at your option.
+# This file may not be copied, modified, or distributed except according to
+# those terms.
+
+import nimcrypto/hash, hashes, stew/byteutils, eth_types, metrics, os
+when defined(posix):
+  import posix
 
 export metrics
 
@@ -10,5 +20,33 @@ proc parseAddress*(hexString: string): EthAddress =
 proc `$`*(a: EthAddress): string =
   a.toHex()
 
+# Block all/most signals in the current thread, so we don't interfere with regular signal
+# handling elsewhere.
+proc ignoreSignalsInThread*() =
+  when defined(posix):
+    var signalMask, oldSignalMask: Sigset
+
+    # sigprocmask() doesn't work on macOS, for multithreaded programs
+    if sigfillset(signalMask) != 0:
+      echo osErrorMsg(osLastError())
+      quit(QuitFailure)
+    when defined(boehmgc):
+      # Turns out Boehm GC needs some signals to deal with threads:
+      # https://www.hboehm.info/gc/debugging.html
+      const
+        SIGPWR = 30
+        SIGXCPU = 24
+        SIGSEGV = 11
+        SIGBUS = 7
+      if sigdelset(signalMask, SIGPWR) != 0 or
+        sigdelset(signalMask, SIGXCPU) != 0 or
+        sigdelset(signalMask, SIGSEGV) != 0 or
+        sigdelset(signalMask, SIGBUS) != 0:
+        echo osErrorMsg(osLastError())
+        quit(QuitFailure)
+    if pthread_sigmask(SIG_BLOCK, signalMask, oldSignalMask) != 0:
+      echo osErrorMsg(osLastError())
+      quit(QuitFailure)
+
 declarePublicGauge connected_peers, "number of peers in the pool"
 

eth/net/nat.nim

@@ -1,4 +1,4 @@
-# Copyright (c) 2019 Status Research & Development GmbH
+# Copyright (c) 2019-2020 Status Research & Development GmbH
 # Licensed under either of
 #  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
 #  * MIT license ([LICENSE-MIT](LICENSE-MIT))
@@ -9,7 +9,8 @@
 import
   options, os, strutils, times,
   stew/results, nat_traversal/[miniupnpc, natpmp],
-  chronicles, json_serialization/std/net
+  chronicles, json_serialization/std/net,
+  eth/common/utils
 
 type
   NatStrategy* = enum
@@ -152,6 +153,7 @@ var
   natCloseChan: Channel[bool]
 
 proc repeatPortMapping(args: PortMappingArgs) {.thread.} =
+  ignoreSignalsInThread()
   let
     (tcpPort, udpPort, description) = args
     interval = initDuration(seconds = PORT_MAPPING_INTERVAL)
@@ -180,11 +182,17 @@ proc repeatPortMapping(args: PortMappingArgs) {.thread.} =
 
 proc stopNatThread() {.noconv.} =
   # stop the thread
+
   natCloseChan.send(true)
   natThread.joinThread()
   natCloseChan.close()
+
   # delete our port mappings
 
+  # FIXME: if the initial port mapping failed because it already existed for the
+  # required external port, we should not delete it. It might have been set up
+  # by another program.
+
   # In Windows, a new thread is created for the signal handler, so we need to
   # initialise our threadvars again.
   let ipres = getExternalIP(strategy, quiet = true)