[mojo] Ports EDK

mojo/edk/embedder/platform_channel_utils_posix.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/edk/embedder/platform_channel_utils_posix.h"
 
 #include <stddef.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
 #include <unistd.h>
@@ skipping 142 matching lines @@
   DCHECK(platform_handles);
 
   struct iovec iov = {buf, num_bytes};
   char cmsg_buf[CMSG_SPACE(kPlatformChannelMaxNumHandles * sizeof(int))];
   struct msghdr msg = {};
   msg.msg_iov = &iov;
   msg.msg_iovlen = 1;
   msg.msg_control = cmsg_buf;
   msg.msg_controllen = sizeof(cmsg_buf);
 
-  // We use SO_PEEK_OFF to hold a common identifier between sockets to detect if
-  // they're connected. recvmsg modifies it, so we cache it and set it again
-  // after the call.
-  int id = 0;
-  socklen_t peek_off_size = sizeof(id);
-  getsockopt(h.handle, SOL_SOCKET, SO_PEEK_OFF, &id, &peek_off_size);
   ssize_t result = HANDLE_EINTR(recvmsg(h.handle, &msg, MSG_DONTWAIT));
   if (result < 0)
     return result;
 
-  setsockopt(h.handle, SOL_SOCKET, SO_PEEK_OFF, &id, sizeof(id));
-
   // Success; no control messages.
   if (msg.msg_controllen == 0)
     return result;
 
   DCHECK(!(msg.msg_flags & MSG_CTRUNC));
 
   for (cmsghdr* cmsg = CMSG_FIRSTHDR(&msg); cmsg;
        cmsg = CMSG_NXTHDR(&msg, cmsg)) {
     if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
       size_t payload_length = cmsg->cmsg_len - CMSG_LEN(0);
       DCHECK_EQ(payload_length % sizeof(int), 0u);
       size_t num_fds = payload_length / sizeof(int);
       const int* fds = reinterpret_cast<int*>(CMSG_DATA(cmsg));
       for (size_t i = 0; i < num_fds; i++) {
         platform_handles->push_back(PlatformHandle(fds[i]));
         DCHECK(platform_handles->back().is_valid());
       }
     }
   }
 
   return result;
 }
 
 }  // namespace edk
 }  // namespace mojo