From d60d0072813046dae7a00874fca601c7fce71e29 Mon Sep 17 00:00:00 2001
From: def <dennis@felsin9.de>
Date: Sun, 4 Jan 2015 22:59:41 +0100
Subject: [PATCH 1/2] Close async socket on error (instead of looping on
 epoll_wait with 100% CPU)

---
 lib/pure/asyncdispatch.nim | 4 ++++
 lib/pure/selectors.nim     | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim
index 4bdce9cfb8..c4abdf9f31 100644
--- a/lib/pure/asyncdispatch.nim
+++ b/lib/pure/asyncdispatch.nim
@@ -878,6 +878,10 @@ else:
       let data = PData(info.key.data)
       assert data.fd == info.key.fd.TAsyncFD
       #echo("In poll ", data.fd.cint)
+      if EvError in info.events:
+        closeSocket(data.fd)
+        continue
+
       if EvRead in info.events:
         # Callback may add items to ``data.readCBs`` which causes issues if
         # we are iterating over ``data.readCBs`` at the same time. We therefore
diff --git a/lib/pure/selectors.nim b/lib/pure/selectors.nim
index 1c988c6091..b796dca7a9 100644
--- a/lib/pure/selectors.nim
+++ b/lib/pure/selectors.nim
@@ -23,7 +23,7 @@ proc `$`*(x: SocketHandle): string {.borrow.}
 
 type
   Event* = enum
-    EvRead, EvWrite
+    EvRead, EvWrite, EvError
 
   SelectorKey* = ref object
     fd*: SocketHandle
@@ -152,6 +152,9 @@ elif defined(linux):
       let fd = s.events[i].data.fd.SocketHandle
     
       var evSet: set[Event] = {}
+      if (s.events[i].events and EPOLLERR) != 0: evSet = evSet + {EvError}
+      if (s.events[i].events and EPOLLHUP) != 0: evSet = evSet + {EvError}
+      if (s.events[i].events and EPOLLRDHUP) != 0: evSet = evSet + {EvError}
       if (s.events[i].events and EPOLLIN) != 0: evSet = evSet + {EvRead}
       if (s.events[i].events and EPOLLOUT) != 0: evSet = evSet + {EvWrite}
       let selectorKey = s.fds[fd]

From f56dcd1505ea90947cd3cece1ac3ef3dcf418e21 Mon Sep 17 00:00:00 2001
From: def <dennis@felsin9.de>
Date: Sun, 4 Jan 2015 23:06:48 +0100
Subject: [PATCH 2/2] Handle interrupt on epoll_wait graciously (allows strace
 to work)

---
 lib/pure/selectors.nim | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/pure/selectors.nim b/lib/pure/selectors.nim
index b796dca7a9..f17c6d3174 100644
--- a/lib/pure/selectors.nim
+++ b/lib/pure/selectors.nim
@@ -146,7 +146,11 @@ elif defined(linux):
     ## on the ``fd``.
     result = @[]
     let evNum = epoll_wait(s.epollFD, addr s.events[0], 64.cint, timeout.cint)
-    if evNum < 0: raiseOSError(osLastError())
+    if evNum < 0:
+      let err = osLastError()
+      if err.cint == EINTR:
+        return @[]
+      raiseOSError(osLastError())
     if evNum == 0: return @[]
     for i in 0 .. <evNum:
       let fd = s.events[i].data.fd.SocketHandle