Revert of [NaCl SDK] nacl_io: Add support for basic socketpairs.

native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
index a141923de0dec3ada5f6a2b3a7d9d10a07a9e908..b554ade35226994cee50d28578dfc2fba3e156db 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
@@ -39,7 +39,6 @@
 #include "nacl_io/pipe/pipe_node.h"
 #include "nacl_io/socket/tcp_node.h"
 #include "nacl_io/socket/udp_node.h"
-#include "nacl_io/socket/unix_node.h"
 #include "nacl_io/stream/stream_fs.h"
 #include "nacl_io/typed_fs_factory.h"
 #include "sdk_util/auto_lock.h"
@@ -1814,73 +1813,21 @@
     return -1;
   }
 
-  if (AF_INET == domain || AF_INET6 == domain) {
-    errno = EOPNOTSUPP;
-    return -1;
-  }
-
+  // Catch-22: We don't support AF_UNIX, but any other AF doesn't support
+  // socket pairs. Thus, this function always fails.
   if (AF_UNIX != domain) {
+    errno = EPROTONOSUPPORT;
+    return -1;
+  }
+
+  if (AF_INET != domain && AF_INET6 != domain) {
     errno = EAFNOSUPPORT;
     return -1;
   }
 
-  if (SOCK_STREAM != type) {
-    errno = EPROTOTYPE;
-    return -1;
-  }
-
-  int open_flags = O_RDWR;
-
-#if defined(SOCK_CLOEXEC)
-  if (type & SOCK_CLOEXEC) {
-#if defined(O_CLOEXEC)
-    // The NaCl newlib version of fcntl.h doesn't currently define
-    // O_CLOEXEC.
-    // TODO(sbc): remove this guard once it gets added.
-    open_flags |= O_CLOEXEC;
-#endif
-    type &= ~SOCK_CLOEXEC;
-  }
-#endif
-
-#if defined(SOCK_NONBLOCK)
-  if (type & SOCK_NONBLOCK) {
-    open_flags |= O_NONBLOCK;
-    type &= ~SOCK_NONBLOCK;
-  }
-#endif
-
-  UnixNode* socket = new UnixNode(stream_fs_.get());
-  Error rtn = socket->Init(O_RDWR);
-  if (rtn != 0) {
-    errno = rtn;
-    return -1;
-  }
-  ScopedNode node0(socket);
-  socket = new UnixNode(stream_fs_.get(), *socket);
-  rtn = socket->Init(O_RDWR);
-  if (rtn != 0) {
-    errno = rtn;
-    return -1;
-  }
-  ScopedNode node1(socket);
-  ScopedKernelHandle handle0(new KernelHandle(stream_fs_, node0));
-  rtn = handle0->Init(open_flags);
-  if (rtn != 0) {
-    errno = rtn;
-    return -1;
-  }
-  ScopedKernelHandle handle1(new KernelHandle(stream_fs_, node1));
-  rtn = handle1->Init(open_flags);
-  if (rtn != 0) {
-    errno = rtn;
-    return -1;
-  }
-
-  sv[0] = AllocateFD(handle0);
-  sv[1] = AllocateFD(handle1);
-
-  return 0;
+  // We cannot reach this point.
+  errno = ENOSYS;
+  return -1;
 }
 
 int KernelProxy::AcquireSocketHandle(int fd, ScopedKernelHandle* handle) {