path: root/src/microhttpd/mhd_itc.h

/*
  This file is part of libmicrohttpd
  Copyright (C) 2016 Karlson2k (Evgeny Grin)

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

*/

/**
 * @file microhttpd/mhd_itc.h
 * @brief  Header for platform-independent inter-thread communication
 * @author Karlson2k (Evgeny Grin)
 * @author Christian Grothoff
 *
 * Provides basic abstraction for inter-thread communication.
 * Any functions can be implemented as macro on some platforms
 * unless explicitly marked otherwise.
 * Any function argument can be skipped in macro, so avoid
 * variable modification in function parameters.
 */
#ifndef MHD_ITC_H
#define MHD_ITC_H 1
#include "mhd_options.h"

/* Force socketpair on native W32 */
#if defined(_WIN32) && !defined(__CYGWIN__) && !defined(_MHD_ITC_SOCKETPAIR)
#error _MHD_ITC_SOCKETPAIR is not defined on naitive W32 platform
#endif /* _WIN32 && !__CYGWIN__ && !_MHD_ITC_SOCKETPAIR */

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <fcntl.h>

#if defined(_MHD_ITC_EVENTFD)
#include <sys/eventfd.h>

/* **************** Optimized GNU/Linux ITC implementation by eventfd ********** */

/**
 * Data type for a MHD ITC.
 */
typedef int MHD_itc_;

/**
 * Initialise ITC by generating eventFD
 * @param itc the itc to initialise
 * @return non-zero if succeeded, zero otherwise
 */
#define MHD_itc_init_(itc) (-1 != ((itc) = eventfd (0, EFD_CLOEXEC | EFD_NONBLOCK)))

/***
 * Get description string of last errno for pipe operations.
 */
#define MHD_pipe_last_strerror_() strerror(errno)

/**
 * write data to real pipe
 */
int
MHD_pipe_write_ (MHD_itc_ pip,
                 const void *ptr,
                 size_t sz);

#define MHD_pipe_get_read_fd_(pip) (pip)

#define MHD_pipe_get_write_fd_(pip) (pip)

/**
 * drain data from real pipe
 */
#define MHD_pipe_drain_(pip) do { \
   uint64_t tmp; \
   read (pip, &tmp, sizeof (tmp)); \
 } while (0)

/**
 * Close any FDs of the pipe (non-W32)
 */
#define MHD_pipe_close_(pip) do { \
    if ( (0 != close (pip)) && \
         (EBADF == errno) )             \
      MHD_PANIC (_("close failed"));    \
  } while (0)

/**
 * Check if we have an uninitialized pipe
 */
#define MHD_INVALID_PIPE_(pip)  (-1 == pip)

/**
 * Setup uninitialized @a pip data structure.
 */
#define MHD_make_invalid_pipe_(pip) do { \
    pip = -1;        \
  } while (0)


/**
 * Change itc FD options to be non-blocking.  As we already did this
 * on eventfd creation, this always succeeds.
 *
 * @param fd the FD to manipulate
 * @return non-zero if succeeded, zero otherwise
 */
#define MHD_itc_nonblocking_(pip) (!0)


#elif defined(_MHD_ITC_PIPE)

/* **************** Standard UNIX ITC implementation by pipe ********** */

#  ifdef HAVE_STRING_H
#    include <string.h> /* for strerror() */
#  endif

/**
 * Data type for a MHD ITC.
 */
struct MHD_Itc
{
  int fd[2];
};
typedef struct MHD_Itc MHD_itc_;

/**
 * Initialise ITC by generating pipe
 * @param itc the itc to initialise
 * @return non-zero if succeeded, zero otherwise
 */
#define MHD_itc_init_(itc) (!pipe((itc).fd))

/***
 * Get description string of last errno for pipe operations.
 */
#define MHD_pipe_last_strerror_() strerror(errno)

/**
 * write data to real pipe
 */
#define MHD_pipe_write_(pip, ptr, sz) write((pip).fd[1], (const void*)(ptr), (sz))


#define MHD_pipe_get_read_fd_(pip) ((pip).fd[0])

#define MHD_pipe_get_write_fd_(pip) ((pip).fd[1])

/**
 * drain data from real pipe
 */
#define MHD_pipe_drain_(pip) do { \
   long tmp; \
   while (0 < read((pip).fd[0], (void*)&tmp, sizeof (tmp))) ; \
 } while (0)

/**
 * Close any FDs of the pipe (non-W32)
 */
#define MHD_pipe_close_(pip) do { \
    if ( (0 != close ((pip).fd[0])) && \
         (EBADF == errno) )             \
      MHD_PANIC (_("close failed"));    \
    if ( (0 != close ((pip).fd[1])) && \
         (EBADF == errno) )             \
      MHD_PANIC (_("close failed"));    \
  } while (0)

/**
 * Check if we have an uninitialized pipe
 */
#define MHD_INVALID_PIPE_(pip)  (-1 == (pip).fd[0])

/**
 * Setup uninitialized @a pip data structure.
 */
#define MHD_make_invalid_pipe_(pip) do { \
    (pip).fd[0] = (pip).fd[1] = -1; \
  } while (0)

/**
 * Change itc FD options to be non-blocking.
 *
 * @param fd the FD to manipulate
 * @return non-zero if succeeded, zero otherwise
 */
int
MHD_itc_nonblocking_ (MHD_itc_ itc);


#elif defined(_MHD_ITC_SOCKETPAIR)

/* **************** ITC implementation by socket pair ********** */

#include "mhd_sockets.h"

/**
 * Data type for a MHD pipe.
 */
struct MHD_Itc
{
  MHD_socket fd[2];
};
typedef struct MHD_Itc MHD_itc_;

/**
 * Initialise ITC by generating socketpair
 * @param itc the itc to initialise
 * @return non-zero if succeeded, zero otherwise
 */
#define MHD_itc_init_(itc) MHD_socket_pair_((itc).fd)

/**
 * Get description string of last pipe error
 */
#define MHD_pipe_last_strerror_() MHD_socket_last_strerr_()

/**
 * Write data to emulated pipe
 */
#define MHD_pipe_write_(pip, ptr, sz) send((pip.fd[1]), (const char*)(ptr), (sz), 0)

#define MHD_pipe_get_read_fd_(pip) (pip.fd[0])

#define MHD_pipe_get_write_fd_(pip) (pip.fd[1])

/**
 * Drain data from emulated pipe
 */
#define MHD_pipe_drain_(pip) do { long tmp; while (0 < recv((pip.fd[0]), (void*)&tmp, sizeof (tmp), 0)) ; } while (0)


/**
 * Close emulated pipe FDs
 */
#define MHD_pipe_close_(pip) do { \
   MHD_socket_close_chk_ ((pip).fd[0]); \
   MHD_socket_close_chk_ ((pip).fd[1]); \
} while (0)

/**
 * Check for uninitialized pipe @a pip
 */
#define MHD_INVALID_PIPE_(pip)  (MHD_INVALID_SOCKET == pip.fd[0])

/**
 * Setup uninitialized @a pip data structure.
 */
#define MHD_make_invalid_pipe_(pip) do { \
    pip.fd[0] = pip.fd[1] = MHD_INVALID_SOCKET; \
  } while (0)


#define MHD_itc_nonblocking_(pip) (MHD_socket_nonblocking_((pip.fd[0])) && MHD_socket_nonblocking_((pip.fd[1])))

#endif /* _MHD_ITC_SOCKETPAIR */

#endif /* MHD_ITC_H */