From f6293d257d9f649ef82ce40850d1b18cca9a89dd Mon Sep 17 00:00:00 2001
From: Martin Hurton <hurtonm@gmail.com>
Date: Wed, 9 Oct 2013 10:51:30 +0200
Subject: [PATCH] Signal that the peer performed orderly shutdown

---
 src/stream_engine.cpp | 77 ++++++++++++++++++++-----------------------
 src/stream_engine.hpp |  7 ++--
 2 files changed, 39 insertions(+), 45 deletions(-)

diff --git a/src/stream_engine.cpp b/src/stream_engine.cpp
index 2c078890..68780d28 100644
--- a/src/stream_engine.cpp
+++ b/src/stream_engine.cpp
@@ -217,17 +217,22 @@ void zmq::stream_engine_t::in_event ()
         //  Note that buffer can be arbitrarily large. However, we assume
         //  the underlying TCP layer has fixed buffer size and thus the
         //  number of bytes read will be always limited.
-        decoder->get_buffer (&inpos, &insize);
-        const int bytes_read = read (inpos, insize);
+        size_t bufsize = 0;
+        decoder->get_buffer (&inpos, &bufsize);
 
-        //  Check whether the peer has closed the connection.
-        if (bytes_read == -1) {
+        int const rc = read (inpos, bufsize);
+        if (rc == 0) {
             error ();
             return;
         }
+        if (rc == -1) {
+            if (errno != EAGAIN)
+                error ();
+            return;
+        }
 
         //  Adjust input size
-        insize = static_cast <size_t> (bytes_read);
+        insize = static_cast <size_t> (rc);
     }
 
     int rc = 0;
@@ -396,12 +401,15 @@ bool zmq::stream_engine_t::handshake ()
     while (greeting_bytes_read < greeting_size) {
         const int n = read (greeting_recv + greeting_bytes_read,
                             greeting_size - greeting_bytes_read);
-        if (n == -1) {
+        if (n == 0) {
             error ();
             return false;
         }
-        if (n == 0)
+        if (n == -1) {
+            if (errno != EAGAIN)
+                error ();
             return false;
+        }
 
         greeting_bytes_read += n;
 
@@ -792,58 +800,45 @@ int zmq::stream_engine_t::read (void *data_, size_t size_)
 {
 #ifdef ZMQ_HAVE_WINDOWS
 
-    int nbytes = recv (s, (char*) data_, (int) size_, 0);
+    const int rc = recv (s, (char*) data_, (int) size_, 0);
 
     //  If not a single byte can be read from the socket in non-blocking mode
     //  we'll get an error (this may happen during the speculative read).
-    if (nbytes == SOCKET_ERROR && WSAGetLastError () == WSAEWOULDBLOCK)
-        return 0;
-
-    //  Connection failure.
-    if (nbytes == SOCKET_ERROR && (
-          WSAGetLastError () == WSAENETDOWN ||
-          WSAGetLastError () == WSAENETRESET ||
-          WSAGetLastError () == WSAECONNABORTED ||
-          WSAGetLastError () == WSAETIMEDOUT ||
-          WSAGetLastError () == WSAECONNRESET ||
-          WSAGetLastError () == WSAECONNREFUSED ||
-          WSAGetLastError () == WSAENOTCONN))
-        return -1;
-
-    wsa_assert (nbytes != SOCKET_ERROR);
-
-    //  Orderly shutdown by the other peer.
-    if (nbytes == 0)
-        return -1; 
+    if (rc == SOCKET_ERROR) {
+        if (WSAGetLastError () == WSAEWOULDBLOCK)
+            errno = EAGAIN;
+        else {
+            wsa_assert (WSAGetLastError () == WSAENETDOWN
+                     || WSAGetLastError () == WSAENETRESET
+                     || WSAGetLastError () == WSAECONNABORTED
+                     || WSAGetLastError () == WSAETIMEDOUT
+                     || WSAGetLastError () == WSAECONNRESET
+                     || WSAGetLastError () == WSAECONNREFUSED
+                     || WSAGetLastError () == WSAENOTCONN);
+            errno = wsa_error_to_errno (WSAGetLastError ());
+        }
+    }
 
-    return nbytes;
+    return rc == SOCKET_ERROR? -1: rc;
 
 #else
 
-    ssize_t nbytes = recv (s, data_, size_, 0);
+    const ssize_t rc = recv (s, data_, size_, 0);
 
     //  Several errors are OK. When speculative read is being done we may not
     //  be able to read a single byte from the socket. Also, SIGSTOP issued
     //  by a debugging tool can result in EINTR error.
-    if (nbytes == -1 && (errno == EAGAIN || errno == EWOULDBLOCK ||
-          errno == EINTR))
-        return 0;
-
-    //  Signalise peer failure.
-    if (nbytes == -1) {
+    if (rc == -1) {
         errno_assert (errno != EBADF
                    && errno != EFAULT
                    && errno != EINVAL
                    && errno != ENOMEM
                    && errno != ENOTSOCK);
-        return -1;
+        if (errno == EWOULDBLOCK || errno == EINTR)
+            errno = EAGAIN;
     }
 
-    //  Orderly shutdown by the peer.
-    if (nbytes == 0)
-        return -1;
-
-    return static_cast <int> (nbytes);
+    return static_cast <int> (rc);
 
 #endif
 }
diff --git a/src/stream_engine.hpp b/src/stream_engine.hpp
index 583a8608..2b3857d5 100644
--- a/src/stream_engine.hpp
+++ b/src/stream_engine.hpp
@@ -87,10 +87,9 @@ namespace zmq
         //  of error or orderly shutdown by the other peer -1 is returned.
         int write (const void *data_, size_t size_);
 
-        //  Reads data from the socket (up to 'size' bytes). Returns the number
-        //  of bytes actually read (even zero is to be considered to be
-        //  a success). In case of error or orderly shutdown by the other
-        //  peer -1 is returned.
+        //  Reads data from the socket (up to 'size' bytes).
+        //  Returns the number of bytes actually read or -1 on error.
+        //  Zero indicates the peer has closed the connection.
         int read (void *data_, size_t size_);
 
         int read_identity (msg_t *msg_);