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  1.   0f48b5dfc0adb748f0a845e4b1b4c06848aabbbb
  2.   src
  3.   examples
  4.   upgrade_example.c
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/*
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     This file is part of libmicrohttpd
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     Copyright (C) 2016 Christian Grothoff (and other contributing authors)
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     This library is free software; you can redistribute it and/or
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     modify it under the terms of the GNU Lesser General Public
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     License as published by the Free Software Foundation; either
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     version 2.1 of the License, or (at your option) any later version.
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     This library is distributed in the hope that it will be useful,
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     but WITHOUT ANY WARRANTY; without even the implied warranty of
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     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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     Lesser General Public License for more details.
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     You should have received a copy of the GNU Lesser General Public
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     License along with this library; if not, write to the Free Software
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     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
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*/
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/**
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 * @file upgrade_example.c
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 * @brief example for how to use libmicrohttpd upgrade
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 * @author Christian Grothoff
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 *
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 * Telnet to the HTTP server, use this in the request:
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 * GET / http/1.1
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 * Connection: Upgrade
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 *
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 * After this, whatever you type will be echo'ed back to you.
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 */
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#include "platform.h"
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#include <microhttpd.h>
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#include <pthread.h>
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#define PAGE "<html><head><title>libmicrohttpd demo</title></head><body>libmicrohttpd demo</body></html>"
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/**
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 * Change socket to blocking.
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 *
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 * @param fd the socket to manipulate
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 * @return non-zero if succeeded, zero otherwise
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 */
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static void
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make_blocking (MHD_socket fd)
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{
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#if defined(MHD_POSIX_SOCKETS)
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  int flags;
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  flags = fcntl (fd, F_GETFL);
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  if (-1 == flags)
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    return;
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  if ((flags & ~O_NONBLOCK) != flags)
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    if (-1 == fcntl (fd, F_SETFL, flags & ~O_NONBLOCK))
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      abort ();
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#elif defined(MHD_WINSOCK_SOCKETS)
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  unsigned long flags = 1;
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  ioctlsocket (fd, FIONBIO, &flags);
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#endif /* MHD_WINSOCK_SOCKETS */
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}
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static void
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send_all (MHD_socket sock,
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          const char *buf,
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          size_t len)
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{
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  ssize_t ret;
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  size_t off;
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  make_blocking (sock);
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  for (off = 0; off < len; off += ret)
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    {
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      ret = send (sock,
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                  &buf[off],
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                  len - off,
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                  0);
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      if (0 > ret)
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        {
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          if (EAGAIN == errno)
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            {
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              ret = 0;
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              continue;
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            }
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          break;
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        }
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      if (0 == ret)
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        break;
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    }
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}
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struct MyData
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{
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  struct MHD_UpgradeResponseHandle *urh;
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  char *extra_in;
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  size_t extra_in_size;
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  MHD_socket sock;
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};
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/**
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 * Main function for the thread that runs the interaction with
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 * the upgraded socket.  Writes what it reads.
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 *
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 * @param cls the `struct MyData`
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 */
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static void *
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run_usock (void *cls)
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{
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  struct MyData *md = cls;
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  struct MHD_UpgradeResponseHandle *urh = md->urh;
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  char buf[128];
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  ssize_t got;
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  make_blocking (md->sock);
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  /* start by sending extra data MHD may have already read, if any */
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  if (0 != md->extra_in_size)
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    {
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      send_all (md->sock,
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                md->extra_in,
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                md->extra_in_size);
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      free (md->extra_in);
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    }
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  /* now echo in a loop */
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  while (1)
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    {
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      got = recv (md->sock,
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                  buf,
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                  sizeof (buf),
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                  0);
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      if (0 >= got)
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        break;
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      send_all (md->sock,
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                buf,
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                got);
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    }
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  free (md);
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  MHD_upgrade_action (urh,
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                      MHD_UPGRADE_ACTION_CLOSE);
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  return NULL;
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}
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/**
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 * Function called after a protocol "upgrade" response was sent
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 * successfully and the socket should now be controlled by some
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 * protocol other than HTTP.
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 *
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 * Any data already received on the socket will be made available in
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 * @e extra_in.  This can happen if the application sent extra data
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 * before MHD send the upgrade response.  The application should
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 * treat data from @a extra_in as if it had read it from the socket.
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 *
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 * Note that the application must not close() @a sock directly,
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 * but instead use #MHD_upgrade_action() for special operations
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 * on @a sock.
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 *
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 * Data forwarding to "upgraded" @a sock will be started as soon
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 * as this function return.
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 *
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 * Except when in 'thread-per-connection' mode, implementations
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 * of this function should never block (as it will still be called
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 * from within the main event loop).
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 *
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 * @param cls closure, whatever was given to #MHD_create_response_for_upgrade().
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 * @param connection original HTTP connection handle,
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 *                   giving the function a last chance
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 *                   to inspect the original HTTP request
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 * @param con_cls last value left in `con_cls` of the `MHD_AccessHandlerCallback`
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 * @param extra_in if we happened to have read bytes after the
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 *                 HTTP header already (because the client sent
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 *                 more than the HTTP header of the request before
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 *                 we sent the upgrade response),
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 *                 these are the extra bytes already read from @a sock
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 *                 by MHD.  The application should treat these as if
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 *                 it had read them from @a sock.
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 * @param extra_in_size number of bytes in @a extra_in
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 * @param sock socket to use for bi-directional communication
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 *        with the client.  For HTTPS, this may not be a socket
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 *        that is directly connected to the client and thus certain
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 *        operations (TCP-specific setsockopt(), getsockopt(), etc.)
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 *        may not work as expected (as the socket could be from a
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 *        socketpair() or a TCP-loopback).  The application is expected
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 *        to perform read()/recv() and write()/send() calls on the socket.
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 *        The application may also call shutdown(), but must not call
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 *        close() directly.
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 * @param urh argument for #MHD_upgrade_action()s on this @a connection.
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 *        Applications must eventually use this callback to (indirectly)
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 *        perform the close() action on the @a sock.
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 */
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static void
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uh_cb (void *cls,
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       struct MHD_Connection *connection,
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       void *con_cls,
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       const char *extra_in,
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       size_t extra_in_size,
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       MHD_socket sock,
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       struct MHD_UpgradeResponseHandle *urh)
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{
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  struct MyData *md;
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  pthread_t pt;
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  (void)cls;         /* Unused. Silent compiler warning. */
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  (void)connection;  /* Unused. Silent compiler warning. */
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  (void)con_cls;     /* Unused. Silent compiler warning. */
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  md = malloc (sizeof (struct MyData));
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  if (NULL == md)
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    abort ();
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  memset (md, 0, sizeof (struct MyData));
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  if (0 != extra_in_size)
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    {
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      md->extra_in = malloc (extra_in_size);
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      if (NULL == md->extra_in)
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        abort ();
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      memcpy (md->extra_in,
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              extra_in,
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              extra_in_size);
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    }
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  md->extra_in_size = extra_in_size;
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  md->sock = sock;
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  md->urh = urh;
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  if (0 != pthread_create (&pt,
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                           NULL,
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                           &run_usock,
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                           md))
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    abort ();
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  /* Note that by detaching like this we make it impossible to ensure
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     a clean shutdown, as the we stop the daemon even if a worker thread
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     is still running. Alas, this is a simple example... */
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  pthread_detach (pt);
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  /* This callback must return as soon as possible. */
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  /* Data forwarding to "upgraded" socket will be started
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   * after return from this callback. */
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}
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static int
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ahc_echo (void *cls,
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          struct MHD_Connection *connection,
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          const char *url,
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          const char *method,
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          const char *version,
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          const char *upload_data,
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          size_t *upload_data_size,
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          void **ptr)
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{
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  static int aptr;
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  struct MHD_Response *response;
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  int ret;
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  (void)cls;               /* Unused. Silent compiler warning. */
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  (void)url;               /* Unused. Silent compiler warning. */
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  (void)version;           /* Unused. Silent compiler warning. */
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  (void)upload_data;       /* Unused. Silent compiler warning. */
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  (void)upload_data_size;  /* Unused. Silent compiler warning. */
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  if (0 != strcmp (method, "GET"))
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    return MHD_NO;              /* unexpected method */
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  if (&aptr != *ptr)
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    {
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      /* do never respond on first call */
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      *ptr = &apt;;
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      return MHD_YES;
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    }
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  *ptr = NULL;                  /* reset when done */
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  response = MHD_create_response_for_upgrade (&uh_cb,
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                                              NULL);
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  MHD_add_response_header (response,
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                           MHD_HTTP_HEADER_UPGRADE,
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                           "Echo Server");
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  ret = MHD_queue_response (connection,
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                            MHD_HTTP_SWITCHING_PROTOCOLS,
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                            response);
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  MHD_destroy_response (response);
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  return ret;
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}
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int
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main (int argc,
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      char *const *argv)
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{
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  struct MHD_Daemon *d;
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  if (argc != 2)
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    {
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      printf ("%s PORT\n", argv[0]);
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      return 1;
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    }
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  d = MHD_start_daemon (MHD_ALLOW_UPGRADE | MHD_USE_AUTO | MHD_USE_INTERNAL_POLLING_THREAD | MHD_USE_ERROR_LOG,
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                        atoi (argv[1]),
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                        NULL, NULL,
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                        &ahc_echo, NULL,
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			MHD_OPTION_CONNECTION_TIMEOUT, (unsigned int) 120,
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			MHD_OPTION_END);
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  if (d == NULL)
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    return 1;
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  (void) getc (stdin);
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  MHD_stop_daemon (d);
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  return 0;
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}

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