/* assuan-socket-server.c - Assuan socket based server

 * Copyright (C) 2002, 2007, 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>

#include <errno.h>

#ifdef HAVE_UNISTD_H

# include <unistd.h>

#endif

#ifdef HAVE_SYS_TYPES_H

# include <sys/types.h>

#endif

#ifdef HAVE_UCRED_H

#include <ucred.h>

#endif

#ifdef HAVE_W32_SYSTEM

# ifdef HAVE_WINSOCK2_H

#  include <winsock2.h>

# endif

# include <windows.h>

# if HAVE_SYS_SOCKET_H

#  include <sys/socket.h>

# elif HAVE_WS2TCPIP_H

#  include <ws2tcpip.h>

# endif

#else

# include <sys/socket.h>

# include <sys/un.h>

#endif

#include "debug.h"

#include "assuan-defs.h"

static gpg_error_t

accept_connection_bottom (assuan_context_t ctx)

{

  assuan_fd_t fd = ctx->connected_fd;

  TRACE (ctx, ASSUAN_LOG_SYSIO, "accept_connection_bottom", ctx);

  ctx->peercred_valid = 0;

#ifdef HAVE_SO_PEERCRED

  {

    struct ucred cr;

    socklen_t cl = sizeof cr;

    if ( !getsockopt (fd, SOL_SOCKET, SO_PEERCRED, &cr, &cl))

      {

         ctx->peercred.pid = cr.pid;

         ctx->peercred.uid = cr.uid;

         ctx->peercred.gid = cr.gid;

         ctx->peercred_valid = 1;

         /* This overrides any already set PID if the function returns

            a valid one. */

         if (cr.pid != ASSUAN_INVALID_PID && cr.pid)

           ctx->pid = cr.pid;

      }

  }

#elif defined (HAVE_GETPEERUCRED)

  {

    ucred_t *ucred = NULL;

    if (getpeerucred (fd, &ucred) != -1)

      {

        ctx->peercred.uid = ucred_geteuid (ucred);

        ctx->peercred.gid = ucred_getegid (ucred);

	ctx->peercred.pid = ucred_getpid (ucred);

	ctx->peercred_valid = 1;

	ucred_free (ucred);

      }

  }

#elif defined (HAVE_LOCAL_PEEREID)

  {

    struct unpcbid unp;

    socklen_t unpl = sizeof unp;

    if (getsockopt (fd, 0, LOCAL_PEEREID, &unp, &unpl) != -1)

      {

	ctx->peercred.pid = unp.unp_pid;

	ctx->peercred.uid = unp.unp_euid;

	ctx->peercred.gid = unp.unp_egid;

	ctx->peercred_valid = 1;

      }

  }

#elif defined(HAVE_GETPEEREID)

  {

    if (getpeereid (fd, &ctx->peercred.uid, &ctx->peercred.gid) != -1)

      {

	ctx->peercred.pid = ASSUAN_INVALID_PID;

	ctx->peercred_valid = 1;

      }

  }

#endif

  ctx->inbound.fd = fd;

  ctx->inbound.eof = 0;

  ctx->inbound.linelen = 0;

  ctx->inbound.attic.linelen = 0;

  ctx->inbound.attic.pending = 0;

  ctx->outbound.fd = fd;

  ctx->outbound.data.linelen = 0;

  ctx->outbound.data.error = 0;

  ctx->flags.confidential = 0;

  return 0;

}

static gpg_error_t

accept_connection (assuan_context_t ctx)

{

  assuan_fd_t fd;

  struct sockaddr_un clnt_addr;

  socklen_t len = sizeof clnt_addr;

  TRACE1 (ctx, ASSUAN_LOG_SYSIO, "accept_connection", ctx,

         "listen_fd=0x%x", ctx->listen_fd);

  fd = SOCKET2HANDLE(accept (HANDLE2SOCKET(ctx->listen_fd),

                             (struct sockaddr*)&clnt_addr, &len ));

  if (fd == ASSUAN_INVALID_FD)

    {

      return _assuan_error (ctx, gpg_err_code_from_syserror ());

    }

  TRACE1 (ctx, ASSUAN_LOG_SYSIO, "accept_connection", ctx,

          "fd->0x%x", fd);

  if (_assuan_sock_check_nonce (ctx, fd, &ctx->listen_nonce))

    {

      _assuan_close (ctx, fd);

      return _assuan_error (ctx, GPG_ERR_ASS_ACCEPT_FAILED);

    }

  ctx->connected_fd = fd;

  return accept_connection_bottom (ctx);

}

/*

   Flag bits: 0 - use sendmsg/recvmsg to allow descriptor passing

              1 - FD has already been accepted.

*/

gpg_error_t

assuan_init_socket_server (assuan_context_t ctx, assuan_fd_t fd,

			   unsigned int flags)

{

  gpg_error_t rc;

  TRACE_BEG2 (ctx, ASSUAN_LOG_CTX, "assuan_init_socket_server", ctx,

	      "fd=0x%x, flags=0x%x", fd, flags);

  rc = _assuan_register_std_commands (ctx);

  if (rc)

    return TRACE_ERR (rc);

  ctx->engine.release = _assuan_server_release;

  ctx->engine.readfnc = _assuan_simple_read;

  ctx->engine.writefnc = _assuan_simple_write;

  ctx->engine.sendfd = NULL;

  ctx->engine.receivefd = NULL;

  ctx->is_server = 1;

  if (flags & ASSUAN_SOCKET_SERVER_ACCEPTED)

    /* We want a second accept to indicate EOF. */

    ctx->max_accepts = 1;

  else

    ctx->max_accepts = -1;

  ctx->input_fd = ASSUAN_INVALID_FD;

  ctx->output_fd = ASSUAN_INVALID_FD;

  ctx->inbound.fd = ASSUAN_INVALID_FD;

  ctx->outbound.fd = ASSUAN_INVALID_FD;

  if (flags & ASSUAN_SOCKET_SERVER_ACCEPTED)

    {

      ctx->listen_fd = ASSUAN_INVALID_FD;

      ctx->connected_fd = fd;

    }

  else

    {

      ctx->listen_fd = fd;

      ctx->connected_fd = ASSUAN_INVALID_FD;

    }

  ctx->accept_handler = ((flags & ASSUAN_SOCKET_SERVER_ACCEPTED)

                         ? accept_connection_bottom

                         : accept_connection);

  ctx->finish_handler = _assuan_server_finish;

  if (flags & ASSUAN_SOCKET_SERVER_FDPASSING)

    _assuan_init_uds_io (ctx);

  rc = _assuan_register_std_commands (ctx);

  if (rc)

    _assuan_reset (ctx);

  return TRACE_ERR (rc);

}

/* Save a copy of NONCE in context CTX.  This should be used to

   register the server's nonce with an context established by

   assuan_init_socket_server.  */

void

assuan_set_sock_nonce (assuan_context_t ctx, assuan_sock_nonce_t *nonce)

{

  if (ctx && nonce)

    ctx->listen_nonce = *nonce;

}