/* assuan-pipe-server.c - Assuan server working over a pipe
 * Copyright (C) 2001, 2002, 2009 Free Software Foundation, Inc.
 *
 * This file is part of Assuan.
 *
 * Assuan 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.
 *
 * Assuan 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 program; if not, see <http://www.gnu.org/licenses/>.
 * SPDX-License-Identifier: LGPL-2.1+
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_W32_SYSTEM
# ifdef HAVE_WINSOCK2_H
#  include <winsock2.h>
# endif
# include <windows.h>
#ifdef HAVE_FCNTL_H
# include <fcntl.h>
#endif
#endif

#include "assuan-defs.h"
#include "debug.h"

/* Returns true if atoi(S) denotes a valid socket. */
#ifndef HAVE_W32_SYSTEM
static int
is_valid_socket (const char *s)
{
  struct stat buf;

  if ( fstat (atoi (s), &buf ) )
    return 0;
  return S_ISSOCK (buf.st_mode);
}
#endif /*!HAVE_W32_SYSTEM*/


/* This actually is a int file descriptor (and not assuan_fd_t) as
   _get_osfhandle is called on W32 systems.  */
gpg_error_t
assuan_init_pipe_server (assuan_context_t ctx, assuan_fd_t filedes[2])
{
  const char *s;
  unsigned long ul;
  gpg_error_t rc;
  assuan_fd_t infd = ASSUAN_INVALID_FD;
  assuan_fd_t outfd = ASSUAN_INVALID_FD;
  int is_usd = 0;
  TRACE_BEG (ctx, ASSUAN_LOG_CTX, "assuan_init_pipe_server", ctx);
  if (filedes)
    {
      TRACE_LOG2 ("fd[0]=0x%x, fd[1]=0x%x", filedes[0], filedes[1]);
    }

  rc = _assuan_register_std_commands (ctx);
  if (rc)
    return TRACE_ERR (rc);

#ifdef HAVE_W32_SYSTEM
  infd  = filedes[0];
  outfd = filedes[1];
#else
  s = getenv ("_assuan_connection_fd");
  if (s && *s && is_valid_socket (s))
    {
      /* Well, we are called with an bi-directional file descriptor.
	 Prepare for using sendmsg/recvmsg.  In this case we ignore
	 the passed file descriptors. */
      infd = atoi (s);
      outfd = atoi (s);
      is_usd = 1;

    }
  else if (filedes && filedes[0] != ASSUAN_INVALID_FD
	   && filedes[1] != ASSUAN_INVALID_FD )
    {
      /* Standard pipe server. */
      infd = filedes[0];
      outfd = filedes[1];
    }
  else
    {
      rc = _assuan_error (ctx, GPG_ERR_ASS_SERVER_START);
      return TRACE_ERR (rc);
    }
#endif

  ctx->flags.is_server = 1;
  ctx->engine.release = _assuan_server_release;
  ctx->engine.readfnc = _assuan_simple_read;
  ctx->engine.writefnc = _assuan_simple_write;
  ctx->engine.sendfd = NULL;
#ifdef HAVE_W32_SYSTEM
  ctx->engine.receivefd = w32_fdpass_recv;
#else
  ctx->engine.receivefd = NULL;
#endif
  ctx->max_accepts = 1;

  s = getenv ("_assuan_pipe_connect_pid");
  if (s && (ul=strtoul (s, NULL, 10)) && ul)
    ctx->pid = (pid_t)ul;
  else
    ctx->pid = (pid_t)-1;
  ctx->accept_handler = NULL;
  ctx->finish_handler = _assuan_server_finish;
  ctx->inbound.fd = infd;
  ctx->outbound.fd = outfd;

  if (is_usd)
    _assuan_init_uds_io (ctx);

  return TRACE_SUC();
}