# SYNOPSIS

#

#   MHD_CHECK_SOCKET_SHUTDOWN_TRIGGER([ACTION-IF-TRIGGER], [ACTION-IF-NOT],

#                                     [ACTION-IF-UNKNOWN])

#

# DESCRIPTION

#

#   Check whether shutdown of listen socket triggers waiting select().

#   If cross-compiling, result may be unknown (third action).

#   Result is cached in $mhd_cv_host_shtdwn_trgr_select variable.

#

# LICENSE

#

#   Copyright (c) 2017 Karlson2k (Evgeny Grin) <k2k@narod.ru>

#

#   Copying and distribution of this file, with or without modification, are

#   permitted in any medium without royalty provided the copyright notice

#   and this notice are preserved. This file is offered as-is, without any

#   warranty.

#serial 2

AC_DEFUN([MHD_CHECK_SOCKET_SHUTDOWN_TRIGGER],[dnl

  AC_PREREQ([2.64])dnl

  AC_REQUIRE([AC_CANONICAL_HOST])dnl

  AC_REQUIRE([AC_PROG_CC])dnl

  AC_REQUIRE([AX_PTHREAD])dnl

  AC_CHECK_HEADERS([sys/time.h],[AC_CHECK_FUNCS([gettimeofday])],[], [AC_INCLUDES_DEFAULT])

  AC_CHECK_HEADERS([time.h],[AC_CHECK_FUNCS([[nanosleep]])],[], [AC_INCLUDES_DEFAULT])

  AC_CHECK_HEADERS([unistd.h],[AC_CHECK_FUNCS([usleep])],[], [AC_INCLUDES_DEFAULT])

  AC_CHECK_HEADERS([string.h sys/types.h sys/socket.h netinet/in.h time.h sys/select.h netinet/tcp.h],[],[], [AC_INCLUDES_DEFAULT])

  AC_CACHE_CHECK([[whether shutdown of listen socket trigger select()]],

    [[mhd_cv_host_shtdwn_trgr_select]], [dnl

    _MHD_OS_KNOWN_SOCKET_SHUTDOWN_TRIGGER([[mhd_cv_host_shtdwn_trgr_select]])

    AS_VAR_IF([mhd_cv_host_shtdwn_trgr_select], [["maybe"]],

      [_MHD_RUN_CHECK_SOCKET_SHUTDOWN_TRIGGER([[mhd_cv_host_shtdwn_trgr_select]])])

    ]

  )

  AS_IF([[test "x$mhd_cv_host_shtdwn_trgr_select" = "xyes"]], [$1],

    [[test "x$mhd_cv_host_shtdwn_trgr_select" = "xno"]], [$2], [$3])

  ]

)

#

# _MHD_OS_KNOWN_SOCKET_SHUTDOWN_TRIGGER(VAR)

#

# Sets VAR to 'yes', 'no' or 'maybe'.

AC_DEFUN([_MHD_OS_KNOWN_SOCKET_SHUTDOWN_TRIGGER],[dnl

[#] On Linux shutdown of listen socket always trigger select().

[#] On Windows select() always ignore shutdown of listen socket.

[#] On other paltforms result may vary depending on platform version.

  AS_CASE([[$host_os]],

    [[linux | linux-* | *-linux | *-linux-*]], [$1='yes'],

    [[mingw*]], [$1='no'],

    [[cygwin* | msys*]], [$1='no'],

    [[winnt* | interix*]], [$1='no'],

    [[mks]], [$1='no'],

    [[uwin]], [$1='no'],

    [$1='maybe']

  )

  ]

)

#

# _MHD_RUN_CHECK_SOCKET_SHUTDOWN_TRIGGER(VAR)

#

# Sets VAR to 'yes', 'no' or 'guessing no'.

AC_DEFUN([_MHD_RUN_CHECK_SOCKET_SHUTDOWN_TRIGGER],[dnl

  AC_LANG_PUSH([C])

  MHD_CST_SAVE_CC="$CC"

  MHD_CST_SAVE_CFLAGS="$CFLAGS"

  MHD_CST_SAVE_LIBS="$LIBS"

  CC="$PTHREAD_CC"

  CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

  LIBS="$PTHREAD_LIBS $LIBS"

  AC_RUN_IFELSE([AC_LANG_SOURCE([[

#include <stdlib.h>

#ifdef HAVE_UNISTD_H

#  include <unistd.h>

#endif

#ifdef HAVE_TIME_H

#  include <time.h>

#endif

#ifdef HAVE_STRING_H

#  include <string.h>

#endif

#if !defined(_WIN32) || defined(__CYGWIN__)

#  ifdef HAVE_SYS_TYPES_H

#    include <sys/types.h>

#  endif

#  ifdef HAVE_SYS_SOCKET_H

#    include <sys/socket.h>

#  endif

#  ifdef HAVE_NETINET_IN_H

#    include <netinet/in.h>

#  endif

#  ifdef HAVE_SYS_TIME_H

#    include <sys/time.h>

#  endif

#  ifdef HAVE_SYS_SELECT_H

#    include <sys/select.h>

#  endif

#  ifdef HAVE_NETINET_TCP_H

#    include <netinet/tcp.h>

#  endif

   typedef int MHD_socket;

#  define MHD_INVALID_SOCKET (-1)

#  define MHD_POSIX_SOCKETS 1

#else

#  include <winsock2.h>

#  include <ws2tcpip.h>

#  include <windows.h>

   typedef SOCKET MHD_socket;

#  define MHD_INVALID_SOCKET (INVALID_SOCKET)

#  define MHD_WINSOCK_SOCKETS 1

#endif

#include <pthread.h>

   #ifndef SHUT_RD

#  define SHUT_RD 0

#endif

#ifndef SHUT_WR

#  define SHUT_WR 1

#endif

#ifndef SHUT_RDWR

#  define SHUT_RDWR 2

#endif

#ifndef NULL

#  define NULL ((void*)0)

#endif

#ifdef HAVE_GETTIMEOFDAY

#  if defined(_WIN32) && !defined(__CYGWIN__)

#    undef HAVE_GETTIMEOFDAY

#  endif

#endif

#ifdef HAVE_NANOSLEEP

static const struct timespec sm_tmout = {0, 1000};

#  define short_sleep() nanosleep(&sm_tmout, NULL)

#elif defined(HAVE_USLEEP)

#  define short_sleep() usleep(1)

#else

#  define short_sleep() (void)0

#endif

static volatile int going_select = 0;

static volatile int select_ends = 0;

static volatile int gerror = 0;

static int timeout_mils;

#ifndef HAVE_GETTIMEOFDAY

static volatile long long select_elapsed_time = 0;

static long long time_chk(void)

{

  long long ret = time(NULL);

  if (-1 == ret)

    gerror = 4;

  return ret;

}

#endif

static void* select_thrd_func(void* param)

{

#ifndef HAVE_GETTIMEOFDAY

  long long start, stop;

#endif

  fd_set rs;

  struct timeval tmot = {0, 0};

  MHD_socket fd = *((MHD_socket*)param);

  FD_ZERO(&rs);

  FD_SET(fd, &rs);

  tmot.tv_usec = timeout_mils * 1000;

#ifndef HAVE_GETTIMEOFDAY

  start = time_chk();

#endif

  going_select = 1;

  if (0 > select ((int)(fd) + 1, &rs, NULL, NULL, &tmot))

    gerror = 5;

#ifndef HAVE_GETTIMEOFDAY

  stop = time_chk();

  select_elapsed_time = stop - start;

#endif

  select_ends = 1;

  return NULL;

}

static MHD_socket create_socket(void)

{ return socket (AF_INET, SOCK_STREAM, 0); }

static void close_socket(MHD_socket fd)

{

#ifdef MHD_POSIX_SOCKETS

  close(fd);

#else

  closesocket(fd);

#endif

}

static MHD_socket

create_socket_listen(int port)

{

  MHD_socket fd;

  struct sockaddr_in sock_addr;

  fd = create_socket();

  if (MHD_INVALID_SOCKET == fd)

    return fd;

  memset (&sock_addr, 0, sizeof (struct sockaddr_in));

  sock_addr.sin_family = AF_INET;

  sock_addr.sin_port = htons(port);

  sock_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

  if (bind (fd, (const struct sockaddr*) &sock_addr, sizeof(sock_addr)) < 0 ||

      listen(fd, SOMAXCONN) < 0)

    {

      close_socket(fd);

      return MHD_INVALID_SOCKET;

    }

  return fd;

}

#ifdef HAVE_GETTIMEOFDAY

#define diff_time(tv1, tv2) ((long long)(tv1.tv_sec-tv2.tv_sec)*10000 + (long long)(tv1.tv_usec-tv2.tv_usec)/100)

#else

#define diff_time(tv1, tv2) ((long long)(tv1-tv2))

#endif

static long long test_run_select(int timeout_millsec, int use_shutdown, long long delay_before_shutdown)

{

  pthread_t select_thrd;

  MHD_socket fd;

#ifdef HAVE_GETTIMEOFDAY

  struct timeval start, stop;

#else

  long long start;

#endif

  fd = create_socket_listen(0);

  if (MHD_INVALID_SOCKET == fd)

    return -7;

  going_select = 0;

  select_ends = 0;

  gerror = 0;

  timeout_mils = timeout_millsec;

  if (0 != pthread_create (&select_thrd, NULL, select_thrd_func, (void*)&fd))

    return -8;

  while (!going_select) {short_sleep();}

#ifdef HAVE_GETTIMEOFDAY

  gettimeofday (&start, NULL);

#else

  start = time_chk();

#endif

  if (use_shutdown)

    {

#ifdef HAVE_GETTIMEOFDAY

      struct timeval current;

      do {short_sleep(); gettimeofday(&current, NULL); } while (delay_before_shutdown > diff_time(current, start));

#else

      while (delay_before_shutdown > time_chk() - start) {short_sleep();}

#endif

      shutdown(fd, SHUT_RDWR);

    }

#ifdef HAVE_GETTIMEOFDAY

  while (!select_ends) {short_sleep();}

  gettimeofday (&stop, NULL);

#endif

  if (0 != pthread_join(select_thrd, NULL))

    return -9;

  close_socket(fd);

  if (gerror)

    return -10;

#ifdef HAVE_GETTIMEOFDAY

  return (long long)diff_time(stop, start);

#else

  return select_elapsed_time;

#endif

}

static int test_it(void)

{

  long long duration2;

#ifdef HAVE_GETTIMEOFDAY

  long long duration0, duration1;

  duration0 = test_run_select(0, 0, 0);

  if (0 > duration0)

    return -duration0;

  duration1 = test_run_select(50, 0, 0);

  if (0 > duration1)

    return -duration1 + 20;

  duration2 = test_run_select(500, 1, (duration0 + duration1) / 2);

  if (0 > duration2)

    return -duration2 + 40;

  if (duration1 * 2 > duration2)

    { /* Check second time to be sure. */

      duration2 = test_run_select(500, 1, (duration0 + duration1) / 2);

      if (0 > duration2)

        return -duration2 + 60;

      if (duration1 * 2 > duration2)

        return 0;

    }

#else

  duration2 = test_run_select(5000, 1, 2);

  if (0 > duration2)

    return -duration2 + 80;

  if (4 > duration2)

    { /* Check second time to be sure. */

      duration2 = test_run_select(5000, 1, 2);

      if (0 > duration2)

      return -duration2 + 100;

      if (4 > duration2)

        return 0;

    }

#endif

  return 1;

}

static int init(void)

{

#ifdef MHD_WINSOCK_SOCKETS

  WSADATA wsa_data;

  if (0 != WSAStartup(MAKEWORD(2, 2), &wsa_data) || MAKEWORD(2, 2) != wsa_data.wVersion)

    {

      WSACleanup();

      return 0;

    }

#endif /* MHD_WINSOCK_SOCKETS */

  return 1;

}

static void cleanup(void)

{

#ifdef MHD_WINSOCK_SOCKETS

  WSACleanup();

#endif /* MHD_WINSOCK_SOCKETS */

}

int main(void)

{

  int res;

  if (!init())

    return 19;

  res = test_it();

  cleanup();

  if (gerror)

    return gerror;

  return res;

}

]])], [$1='yes'], [$1='no'], [$1='guessing no'])

  CC="$MHD_CST_SAVE_CC"

  CFLAGS="$MHD_CST_SAVE_CFLAGS"

  LIBS="$MHD_CST_SAVE_LIBS"

  AS_UNSET([[MHD_CST_SAVE_CC]])

  AS_UNSET([[MHD_CST_SAVE_CFLAGS]])

  AS_UNSET([[MHD_CST_SAVE_LIBS]])

  AC_LANG_POP([C])

  ]

)