micro_http: gracefully handle EINTR

EINTR errors should not break the HttpServer requests loop,
they are internally consumed and reported as no events rather
than requests errors.

Signed-off-by: Adrian Catangiu <acatan@amazon.com>
Signed-off-by: YUAN LYU <lyuyuan92@gmail.com>

src/lib.rs

@@ -109,6 +109,7 @@
 //! }
 //! ```
 
+extern crate libc;
 extern crate utils;
 
 mod common;

src/server.rs

@@ -302,10 +302,11 @@ impl HttpServer {
         // current thread until at least one event is received.
         // The received notifications will then populate the `events` array with
         // `event_count` elements, where 1 <= event_count <= MAX_CONNECTIONS.
-        let event_count = self
-            .epoll
-            .wait(MAX_CONNECTIONS, -1, &mut events[..])
-            .map_err(ServerError::IOError)?;
+        let event_count = match self.epoll.wait(MAX_CONNECTIONS, -1, &mut events[..]) {
+            Ok(event_count) => event_count,
+            Err(e) if e.raw_os_error() == Some(libc::EINTR) => 0,
+            Err(e) => return Err(ServerError::IOError(e)),
+        };
         // We use `take()` on the iterator over `events` as, even though only
         // `events_count` events have been inserted into `events`, the size of
         // the array is still `MAX_CONNECTIONS`, so we discard empty elements