\documentclass{article}
\usepackage{axiom}

\title{\$SPAD/src/lib sockio-c.c}
\author{The Axiom Team}

\begin{document}
\maketitle

\begin{abstract}
\end{abstract}
\eject

\tableofcontents
\eject

\section{License}
<<license>>=
/*
Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    - Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    - Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the
      distribution.

    - Neither the name of The Numerical ALgorithms Group Ltd. nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
@
<<*>>=
<<license>>

/* socket i/o primitives */

#include <stdio.h>
#include <stdlib.h>

#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include <sys/time.h>
#include <string.h>
#include <signal.h>

#include "com.h"
#include "bsdsignal.h"

#define TotalMaxPurposes 50
#define MaxServerNumbers 100
#define accept_if_needed(purpose) \
  ( purpose_table[purpose] == NULL ? sock_accept_connection(purpose) : 1 )

/* Note that the name AF_LOCAL is more portable than AF_UNIX, but MingW
   implementation and Windows documentation don't always agree.  */

#if HAVE_AF_LOCAL
#  define AXIOM_AF_LOCAL AF_LOCAL
#elif HAVE_AF_UNIX
#  define AXIOM_AF_LOCAL AF_UNIX
#else
#  error needs one of AF_LOCAL or AF_UNIX
#endif



Sock clients[MaxClients];       /* socket description of spad clients */
Sock server[2];                 /* AF_LOCAL and AF_INET sockets for server */
Sock *purpose_table[TotalMaxPurposes]; /* table of dedicated socket types */
fd_set socket_mask;             /* bit mask of active sockets */
fd_set server_mask;             /* bit mask of server sockets */
int socket_closed;              /* used to identify closed socket on SIGPIPE */
int spad_server_number = -1;    /* spad server number used in sman */
int str_len = 0;
int still_reading  = 0;



#include "bsdsignal.H1"
#include "sockio-c.H1"

/* The function sleep is not available under Windows.  Instead they
   have Sleep(), with capital S, please.  Furthermore, it does not
   take argument in second, but in milliseconds, three order
   of magnitude of difference when compared to the Unix world.
   We abstract over that difference here.  */

static inline void
axiom_sleep(int n)
{
#ifdef __WIN32__
   Sleep(n * 1000);
#else
   sleep(n);
#endif   
}

/* Windows require some handshaking with the WinSock DLL before
   we can even think about talking about sockets. */

static void
axiom_load_socket_module()
{
#ifdef __WIN32__
   WSADATA wsaData;

   /* Request version 2.0 of WinSock DLL. */
   if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0) {
      perror("could not find suitable WinSock DLL.");
      exit(WSAGetLastError());
   }
   
   if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 0) {
      perror("could not find suitable WinSock DLL.");
      WSACleanup();
      exit(WSAGetLastError());
   }
#endif   
}


/* Get a socket identifier to a local server.  We take whatever protocol
   is the default for the address family in the SOCK_STREAM type.  */
static inline axiom_socket
axiom_communication_link(int family)
{
   axiom_load_socket_module();
   return socket(family, SOCK_STREAM, 0);
}


/* Returns 1 if SOCKET is an invalid socket.  Otherwise return 0.  */

static inline int
is_invalid_socket(const Sock* s)
{
#ifdef __WIN32__
   return s->socket == INVALID_SOCKET;
#else
   return s->socket < 0;
#endif   
}

/* Returns 1 if SOCKET is a valid socket.  Otherwise return 0.  */

static inline int
is_valid_socket(const Sock* s)
{
#ifdef __WIN32__
   return s->socket != INVALID_SOCKET;
#else
   return s->socket > 0;
#endif   
}


/* Because a socket on Windows platform is a not just a simple file
   descriptor as it is in the Unix world, it is invalid to use
   a socket identifier as argument for read(), or close, and
   any other file descriptor function.  Furthermore, Windows
   requires cleanup.  */

void
axiom_close_socket(axiom_socket s)
{
#ifdef __WIN32__
   shutdown(s, SD_BOTH);
   closesocket(s);
   WSACleanup();
#else
   close(s);
#endif
}  

/* Return 1 is the last call was cancelled. */

static inline int
axiom_call_was_cancelled(void)
{
#ifdef __WIN32__
   return WSAGetLastError() == WSAEINTR;
#else
   return errno == EINTR;
#endif
}

/* Return 1 is last connect() was refused.  */

static inline int
axiom_connection_refused(void)
{
#ifdef __WIN32__
   return WSAGetLastError() == WSAECONNREFUSED;
#else
   return errno == ECONNREFUSED;
#endif   
}


void  
sigpipe_handler(int sig)
{
  socket_closed = 1;
}

int 
wait_for_client_read(Sock *sock, char *buf, int buf_size, char *msg)
{
  int ret_val;
  switch(sock->purpose) {
  case SessionManager:
  case ViewportServer:
    sock_accept_connection(sock->purpose);
    ret_val = sread(purpose_table[sock->purpose], buf, buf_size, msg);
    sock->socket = 0;
    return ret_val;
  default:
    sock->socket = 0;
    return -1;
  }
}

int 
wait_for_client_write(Sock *sock,char *buf,int buf_size,char *msg)
{
  int ret_val;
  switch(sock->purpose) {
  case SessionManager:
  case ViewportServer:
    sock_accept_connection(sock->purpose);
    ret_val = swrite(purpose_table[sock->purpose], buf, buf_size, msg);
    sock->socket = 0;
    return ret_val;
  default:
    sock->socket = 0;
    return -1;
  }
}

int 
sread(Sock *sock, char *buf, int buf_size, char *msg)
{
  int ret_val;
  char err_msg[256];
  errno = 0;
  do {
    ret_val = axiom_read(sock, buf, buf_size);
  } while (ret_val == -1 && axiom_call_was_cancelled());
  if (ret_val == 0) {
    FD_CLR(sock->socket, &socket_mask);
    purpose_table[sock->purpose] = NULL;
    axiom_close_socket(sock->socket);
    return wait_for_client_read(sock, buf, buf_size, msg);
  }
  if (ret_val == -1) {
    if (msg) {
      sprintf(err_msg, "reading: %s", msg);
      perror(err_msg);
    }
    return -1;
  }
  return ret_val;
}

int 
swrite(Sock *sock,char *buf,int buf_size,char *msg)
{
  int ret_val;
  char err_msg[256];
  errno = 0;
  socket_closed = 0;
  ret_val = axiom_write(sock, buf, buf_size);
  if (ret_val == -1) {
    if (socket_closed) {
      FD_CLR(sock->socket, &socket_mask);
      purpose_table[sock->purpose] = NULL;
      /*      printf("   closing socket %d\n", sock->socket); */
      axiom_close_socket(sock->socket);
      return wait_for_client_write(sock, buf, buf_size, msg);
    } else {
      if (msg) {
        sprintf(err_msg, "writing: %s", msg);
        perror(err_msg);
      }
      return -1;
    }
  }
  return ret_val;
}

int 
sselect(int n,fd_set  *rd, fd_set  *wr, fd_set *ex, void *timeout)
{
  int ret_val;
  do {
    ret_val = select(n, (void *)rd, (void *)wr, (void *)ex, (struct timeval *) timeout);
  } while (ret_val == -1 && axiom_call_was_cancelled());
  return ret_val;
}

int 
fill_buf(Sock *sock,char *buf, int len, char *msg)
{
  int bytes =  0, ret_val;
  while(bytes < len) {
    ret_val = sread(sock, buf + bytes, len - bytes, msg);
    if (ret_val == -1) return -1;
    bytes += ret_val;
  }
  return bytes;
}

int 
get_int(Sock *sock)
{
  int val = -1, len;
  len = fill_buf(sock, (char *)&val, sizeof(int), "integer");
  if (len != sizeof(int)) {
#ifdef DEBUG
  fprintf(stderr,"get_int: caught error\n",val);
#endif
    return -1;
  }
#ifdef DEBUG
  fprintf(stderr,"get_int: received %d\n",val);
#endif
  return val;
}

int 
sock_get_int(int purpose)
{
  if (accept_if_needed(purpose) != -1)
    return get_int(purpose_table[purpose]);
  else return -1;
}

int 
get_ints(Sock *sock, int *vals, int num)
{
  int i;
  for(i=0; i<num; i++)
    *vals++ = get_int(sock);
  return 0;
}

int 
sock_get_ints(int purpose, int *vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return get_ints(purpose_table[purpose], vals, num);
  return -1;
}

int 
send_int(Sock *sock,int val)
{
  int ret_val;
  ret_val = swrite(sock, (char *)&val, sizeof(int), NULL);
  if (ret_val == -1) {
    return -1;
  }
  return 0;
}

int 
sock_send_int(int purpose,int  val)
{
  if (accept_if_needed(purpose) != -1)
    return send_int(purpose_table[purpose], val);
  return -1;
}

int 
send_ints(Sock *sock, int *vals, int num)
{
  int i;
  for(i=0; i<num; i++)
    if (send_int(sock, *vals++) == -1)
      return -1;
  return 0;
}

int 
sock_send_ints(int purpose, int *vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return send_ints(purpose_table[purpose], vals, num);
  return -1;
}

int 
send_string_len(Sock *sock,char *str,int len)
{
  int val;
  if (len > 1023) {
    char *buf;
    buf = malloc(len+1);
    strncpy(buf,str,len);
    buf[len]='\0';
    send_int(sock,len+1);
    val = swrite(sock, buf, len+1, NULL);
    free(buf);
  } else {
    static char buf[1024];
    strncpy(buf, str, len);
    buf[len] = '\0';
    send_int(sock, len+1);
    val = swrite(sock, buf, len+1, NULL);
  }
  if (val == -1) {
    return -1;
  }
  return 0;
}

int 
send_string(Sock *sock, char *str)
{
  int val, len = strlen(str);
  send_int(sock, len+1);
  val = swrite(sock, str, len+1, NULL);
  if (val == -1) {
    return -1;
  }
  return 0;
}


int 
sock_send_string(int purpose, char *str)
{
  if (accept_if_needed(purpose) != -1)
    return send_string(purpose_table[purpose], str);
  return -1;
}

int 
sock_send_string_len(int purpose, char * str, int len)
{
  if (accept_if_needed(purpose) != -1)
    return send_string_len(purpose_table[purpose], str, len);
  return -1;
}

int 
send_strings(Sock *sock, char ** vals, int num)
{
  int i;
  for(i=0; i<num; i++)
    if (send_string(sock, *vals++) == -1)
      return -1;
  return 0;
}

int 
sock_send_strings(int purpose, char **vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return send_strings(purpose_table[purpose], vals, num);
  return -1;
}

char *
get_string(Sock *sock)
{
  int val, len;
  char *buf;
  len = get_int(sock);
  if (len <0) return NULL;
  buf = malloc(len*sizeof(char));
  val = fill_buf(sock, buf, len, "string");
  if (val == -1){
	free(buf);
	return NULL;
	}
#ifdef DEBUG
  fprintf(stderr,"get_string: received \"%s\" \n",buf);
#endif
  return buf;
}

char *
sock_get_string(int purpose)
{
  if (accept_if_needed(purpose) != -1)
    return get_string(purpose_table[purpose]);
  else return NULL;
}


char *
get_string_buf(Sock *sock, char *buf, int buf_len)
{
  int val;
  if(!str_len) str_len = get_int(sock);
    if (str_len > buf_len) {
      val = fill_buf(sock, buf, buf_len, "buffered string");
      str_len = str_len - buf_len;
      if (val == -1)
        return NULL;
      return buf;
    }
    else {
      val = fill_buf(sock, buf, str_len, "buffered string");
      str_len = 0;
      if (val == -1)
        return NULL;
      return NULL;
    }
}

char *
sock_get_string_buf(int purpose, char * buf, int buf_len)
{
  if (accept_if_needed(purpose) != -1)
    return get_string_buf(purpose_table[purpose], buf, buf_len);
  return NULL;
}

int 
get_strings(Sock *sock,char **vals,int num)
{
  int i;
  for(i=0; i<num; i++)
    *vals++ = get_string(sock);
  return 0;
}

int 
sock_get_strings(int purpose, char ** vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return get_strings(purpose_table[purpose], vals, num);
  return -1;
}

int 
send_float(Sock *sock, double num)
{
  int val;
  val = swrite(sock, (char *)&num, sizeof(double), NULL);
  if (val == -1) {
    return -1;
  }
  return 0;
}

int 
sock_send_float(int purpose, double num)
{
  if (accept_if_needed(purpose) != -1)
    return send_float(purpose_table[purpose], num);
  return -1;
}

int 
send_sfloats(Sock *sock, float *vals,int  num)
{
  int i;
  for(i=0; i<num; i++)
    if (send_float(sock, (double) *vals++) == -1)
      return -1;
  return 0;
}

int 
sock_send_sfloats(int purpose, float * vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return send_sfloats(purpose_table[purpose], vals, num);
  return -1;
}

int 
send_floats(Sock *sock, double *vals, int num)
{
  int i;
  for(i=0; i<num; i++)
    if (send_float(sock, *vals++) == -1)
      return -1;
  return 0;
}

int 
sock_send_floats(int purpose, double  *vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return send_floats(purpose_table[purpose], vals, num);
  return -1;
}

double 
get_float(Sock *sock)
{
  int val;
  double num = -1.0;
  val = fill_buf(sock, (char *)&num, sizeof(double), "double");
#ifdef DEBUG
  fprintf(stderr,"get_float: received %f\n",num);
#endif
  return num;
}

double 
sock_get_float(int purpose)
{
  if (accept_if_needed(purpose) != -1)
    return get_float(purpose_table[purpose]);
  else return 0.0;
}

int 
get_sfloats(Sock *sock, float *vals, int num)
{
  int i;
  for(i=0; i<num; i++)
    *vals++ = (float) get_float(sock);
  return 0;
}


int 
sock_get_sfloats(int purpose,float * vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return get_sfloats(purpose_table[purpose], vals, num);
  return -1;
}

int 
get_floats(Sock *sock,double *vals,int num)
{
  int i;
  for(i=0; i<num; i++)
    *vals++ = get_float(sock);
  return 0;
}


int 
sock_get_floats(int purpose, double *vals, int num)
{
  if (accept_if_needed(purpose) != -1)
    return get_floats(purpose_table[purpose], vals, num);
  return -1;
}

int 
wait_for_client_kill(Sock *sock, int sig)
{
  int ret_val;
  switch(sock->purpose) {
  case SessionManager:
  case ViewportServer:
    sock_accept_connection(sock->purpose);
    ret_val = send_signal(purpose_table[sock->purpose], sig);
    sock->socket = 0;
    return ret_val;
  default:
    sock->socket = 0;
    return -1;
  }
}


int 
sock_get_remote_fd(int purpose)
{
  if (accept_if_needed(purpose) != -1)
    return purpose_table[purpose]->remote;
  return -1;
}

int 
send_signal(Sock *sock, int sig)
{
  int ret_val;
#if HAVE_DECL_KILL
  ret_val = kill(sock->pid, sig);
#else
  ret_val = raise(sig);
#endif  
  if (ret_val == -1 && errno == ESRCH) {
    FD_CLR(sock->socket, &socket_mask);
    purpose_table[sock->purpose] = NULL;
/*    printf("   closing socket %d\n", sock->socket); */
    axiom_close_socket(sock->socket);
    return wait_for_client_kill(sock, sig);
  }
  return ret_val;
}

int 
sock_send_signal(int purpose,int  sig)
{
  if (accept_if_needed(purpose) != -1)
    return send_signal(purpose_table[purpose], sig);
  return -1;
}

int 
send_wakeup(Sock *sock)
{
#ifdef SIGUSR1   
  return send_signal(sock, SIGUSR1);
#else
  return -1;
#endif  
}

int 
sock_send_wakeup(int purpose)
{
  if (accept_if_needed(purpose) != -1)
    return send_wakeup(purpose_table[purpose]);
  return -1;
}

Sock *
connect_to_local_server_new(char *server_name, int purpose, int time_out)
{
  int max_con=(time_out == 0 ? 1000000 : time_out), i, code=-1;
  Sock *sock;
  char name[256];

  make_server_name(name, server_name);
  sock = (Sock *) calloc(sizeof(Sock), 1);
  if (sock == NULL) {
    perror("allocating socket space");
    return NULL;
  }

  sock->socket = axiom_communication_link(AXIOM_AF_LOCAL);
  if (is_invalid_socket(sock)) {
    perror("opening client socket");
    free(sock);
    return NULL;
  }

  memset(server[1].addr.u_addr.sa_data, 0,
         sizeof(server[1].addr.u_addr.sa_data));
  sock->addr.u_addr.sa_family = AXIOM_AF_LOCAL;
  strcpy(sock->addr.u_addr.sa_data, name);
  for(i=0; i<max_con; i++) {
    code = connect(sock->socket, &sock->addr.u_addr,
                   sizeof(sock->addr.u_addr));
    if (code == -1) {
      if (errno != ENOENT && !axiom_connection_refused()) {
        perror("connecting server stream socket");
        return NULL;
      } else {
        if (i != max_con - 1)
           axiom_sleep(1);
        continue;
      }
    } else break;
  }

  if (code == -1) {
    return NULL;
  }

  send_int(sock, getpid());
  send_int(sock, purpose);
  send_int(sock, sock->socket);
  sock->pid = get_int(sock);
  sock->remote = get_int(sock);
  return sock;
}

Sock *
connect_to_local_server(char *server_name, int purpose, int time_out)
{
  int max_con=(time_out == 0 ? 1000000 : time_out), i, code=-1;
  Sock *sock;
  char name[256];

  make_server_name(name, server_name);
  sock = (Sock *) calloc(sizeof(Sock), 1);
  if (sock == NULL) {
    perror("allocating socket space");
    return NULL;
  }

  sock->purpose = purpose;
  /* create the socket */
  sock->socket = axiom_communication_link(AXIOM_AF_LOCAL);
  if (is_invalid_socket(sock)) {
    perror("opening client socket");
    free(sock);
    return NULL;
  }
  /* connect socket using name specified in command line */
  memset(server[1].addr.u_addr.sa_data, 0,
         sizeof(server[1].addr.u_addr.sa_data));
  sock->addr.u_addr.sa_family = AXIOM_AF_LOCAL;
  strcpy(sock->addr.u_addr.sa_data, name);
  for(i=0; i<max_con; i++) {
    code = connect(sock->socket, &sock->addr.u_addr,
                   sizeof(sock->addr.u_addr));
    if (code == -1) {
      if (errno != ENOENT && !axiom_connection_refused()) {
        perror("connecting server stream socket");
        return NULL;
      } else {
        if (i != max_con - 1)
           axiom_sleep(1);
        continue;
      }
    } else break;
  }
  if (code == -1) {
    return NULL;
  }
  send_int(sock, getpid());
  send_int(sock, sock->purpose);
  send_int(sock, sock->socket);
  sock->pid = get_int(sock);
/*  fprintf(stderr, "Got int form socket\n"); */
  sock->remote = get_int(sock);
  return sock;
}

/* act as terminal session for sock connected to stdin and stdout of another
   process */
void 
remote_stdio(Sock *sock)
{
  char buf[1024];
  fd_set rd;
  int len;
  while (1) {
    FD_ZERO(&rd);
    FD_SET(sock->socket,&rd);
    FD_SET(0, &rd);
    len = sselect(FD_SETSIZE, (fd_set *)&rd, (fd_set *)0, (fd_set *)0, NULL);
    if (len == -1) {
      perror("stdio select");
      return;
    }
    if (FD_ISSET(0, &rd)) {
      fgets(buf,1024,stdin);
      len = strlen(buf);
      /*
          gets(buf);
          len = strlen(buf);
          *(buf+len) = '\n';
          *(buf+len+1) = '\0';
      */
      swrite(sock, buf, len, "writing to remote stdin");
    }
    if (FD_ISSET(sock->socket, &rd)) {
      len = sread(sock, buf, 1024, "stdio");
      if (len == -1)
        return;
      else {
        *(buf + len) = '\0';
        fputs(buf, stdout);
        fflush(stdout);
      }
    }
  }
}

/* initialize the table of dedicated sockets */
void 
init_purpose_table(void)
{
  int i;
  for(i=0; i<TotalMaxPurposes; i++) {
    purpose_table[i] = NULL;
  }
}


int 
make_server_number(void)
{
  spad_server_number = getpid();
  return spad_server_number;
}

void 
close_socket(axiom_socket socket_num, char *name)
{
  axiom_close_socket(socket_num);
#ifndef RTplatform
  unlink(name);
#endif
}

int 
make_server_name(char *name,char * base)
{
  char *num;
  if (spad_server_number != -1) {
    sprintf(name, "%s%d", base, spad_server_number);
    return 0;
  }
  num = getenv("SPADNUM");
  if (num == NULL) {
/*    fprintf(stderr,
      "\n(AXIOM Sockets) The AXIOM server number is undefined.\n");
*/
    return -1;
  }
  sprintf(name, "%s%s", base, num);
  return 0;
}

/* client Spad server sockets.  Two sockets are created: server[0]
   is the internet server socket, and server[1] is a local domain socket. */
int 
open_server(char *server_name)
{
  char *s, name[256];

  init_socks();
#ifdef SIGPIPE
  bsdSignal(SIGPIPE, sigpipe_handler,RestartSystemCalls);
#endif  
  if (make_server_name(name, server_name) == -1)
    return -2;
  /* create the socket internet socket */
  server[0].socket = 0;
/*  server[0].socket = axiom_communication_link(AF_INET);
  if (is_invalid_socket(&server[0])) {
    server[0].socket = 0;
  } else {
    server[0].addr.i_addr.sin_family = AF_INET;
    server[0].addr.i_addr.sin_addr.s_addr = INADDR_ANY;
    server[0].addr.i_addr.sin_port = 0;
    if (bind(server[0].socket, &server[0].addr.i_addr,
             sizeof(server[0].addr.i_addr))) {
      perror("binding INET stream socket");
      server[0].socket = 0;
      return -1;
    }
    length = sizeof(server[0].addr.i_addr);
    if (getsockname(server[0].socket, &server[0].addr.i_addr, &length)) {
      perror("getting INET server socket name");
      server[0].socket = 0;
      return -1;
    }
    server_port = ntohs(server[0].addr.i_addr.sin_port);
    FD_SET(server[0].socket, &socket_mask);
    FD_SET(server[0].socket, &server_mask);
    listen(server[0].socket,5);
  } */
  /* Next create the local domain socket */
  server[1].socket = axiom_communication_link(AXIOM_AF_LOCAL);
  if (is_invalid_socket(&server[1])) {
    perror("opening local server socket");
    server[1].socket = 0;
    return -2;
  } else {
    server[1].addr.u_addr.sa_family = AXIOM_AF_LOCAL;
    memset(server[1].addr.u_addr.sa_data, 0,
           sizeof(server[1].addr.u_addr.sa_data));
    strcpy(server[1].addr.u_addr.sa_data, name);
    if (bind(server[1].socket, &server[1].addr.u_addr,
             sizeof(server[1].addr.u_addr))) {
      perror("binding local server socket");
      server[1].socket = 0;
      return -2;
    }
    FD_SET(server[1].socket, &socket_mask);
    FD_SET(server[1].socket, &server_mask);
    listen(server[1].socket, 5);
  }
  s = getenv("SPADSERVER");
  if (s == NULL) {
/*    fprintf(stderr, "Not a spad server system\n"); */
    return -1;
  }
  return 0;
}

int 
accept_connection(Sock *sock)
{
  int client;
  for(client=0; client<MaxClients && clients[client].socket != 0; client++);
  if (client == MaxClients) {
    printf("Ran out of client Sock structures\n");
    return -1;
  }
  clients[client].socket = accept(sock->socket, 0, 0);
  if (is_invalid_socket(&clients[client])) {
    perror("accept_connection");
    clients[client].socket = 0;
    return -1;
  }
  FD_SET(clients[client].socket, &socket_mask);
  get_socket_type(clients+client);
  return clients[client].purpose;
}

/* reads a the socket purpose declaration for classification */
void 
get_socket_type(Sock *sock)
{
  sock->pid = get_int(sock);
  sock->purpose = get_int(sock);
  sock->remote = get_int(sock);
  send_int(sock, getpid());
  send_int(sock, sock->socket);
  purpose_table[sock->purpose] = sock;
  switch (sock->purpose) {
  case SessionManager:
    break;
  case ViewportServer:
    break;
  case MenuServer:
    break;
  case SessionIO:
/*    redirect_stdio(sock); */
    break;
  }
}

int 
sock_accept_connection(int purpose)
{
  fd_set rd;
  int ret_val, i, p;
  if (getenv("SPADNUM") == NULL) return -1;
  while (1) {
    rd = server_mask;
    ret_val = sselect(FD_SETSIZE, (fd_set *)&rd, (fd_set *)0, (fd_set *)0, NULL);
    if (ret_val == -1) {
      /* perror ("Select"); */
      return -1;
    }
    for(i=0; i<2; i++) {
      if (is_valid_socket(&server[i])
          && FD_ISSET(server[i].socket, &rd)) {
        p = accept_connection(server+i);
        if (p == purpose) return 1;
      }
    }
  }
}

/* direct stdin and stdout from the given socket */
void 
redirect_stdio(Sock *sock)
{
  int fd;
/*  setbuf(stdout, NULL);  */
  fd = dup2(sock->socket, 1);
  if (fd != 1) {
    fprintf(stderr, "Error connecting stdout to socket\n");
    return;
  }
  fd = dup2(sock->socket, 0);
  if (fd != 0) {
    fprintf(stderr, "Error connecting stdin to socket\n");
    return;
  }
  fprintf(stderr, "Redirected standard IO\n");
  FD_CLR(sock->socket, &socket_mask);
}

void
init_socks(void)
{
  int i;
  FD_ZERO(&socket_mask);
  FD_ZERO(&server_mask);
  init_purpose_table();
  for(i=0; i<2; i++) server[i].socket = 0;
  for(i=0; i<MaxClients; i++) clients[i].socket = 0;
}

/* Socket I/O selection called from the BOOT serverLoop function */

int 
server_switch(void)
{
  int ret_val, i, cmd = 0;
  fd_set rd, wr, ex, fds_mask;
  FD_ZERO(&rd);
  FD_ZERO(&wr);
  FD_ZERO(&ex);
  fds_mask = server_mask;
  cmd = 0;
  if (purpose_table[SessionManager] != NULL) {
    FD_SET(0, &fds_mask);
    FD_SET(purpose_table[SessionManager]->socket, &fds_mask);
  }
  while (1) {
    do {
      if (purpose_table[MenuServer] != NULL) {
        FD_SET(purpose_table[MenuServer]->socket, &fds_mask);
      }
      rd = fds_mask;
      ret_val = select(FD_SETSIZE, (void *) &rd, (void *) 0, (void *) 0, (void *) 0);
      if (ret_val == -1) {
        /* perror ("Select in switch"); */
        return -1;
      }
      for(i=0; i<2; i++) {
        if (is_valid_socket(&server[i])
            && (FD_ISSET(server[i].socket, &rd)))
          accept_connection(server+i);
      }
    } while (purpose_table[SessionManager] == NULL);
    FD_SET(purpose_table[SessionManager]->socket, &fds_mask);
    if (FD_ISSET(purpose_table[SessionManager]->socket, &rd)) {
      cmd = get_int(purpose_table[SessionManager]);
      return cmd;
    }
    if (FD_ISSET(0, &rd)) {
      return CallInterp;
    }
    if (purpose_table[MenuServer] != NULL &&
        (FD_ISSET(purpose_table[MenuServer]->socket, &rd))) {
      cmd = get_int(purpose_table[MenuServer]);
      return cmd;
    }
  }
}

void 
flush_stdout(void)
{
  static FILE *fp = NULL;
  if (fp == NULL) {
    fp = fdopen(purpose_table[SessionIO]->socket, "w");
    if (fp == NULL) {
      perror("fdopen");
      return;
    }
  }
  fflush(fp);
}

void 
print_line(char *s)
{
  printf("%s\n", s);
}


typedef union {
  double        f;
  long          l[2];
	} DoubleFloat;

double 
plus_infinity(void )
{
  static int init = 0;
  static DoubleFloat pinf;
  if (! init) {
    pinf.l[0] = 0x7ff00000;
    pinf.l[1] = 0;
    init = 1;
  }
  return pinf.f;
}

double 
minus_infinity(void)
{
  static int init = 0;
  static DoubleFloat minf;
  if (! init) {
    minf.l[0] = 0xfff00000L;
    minf.l[1] = 0;
    init = 1;
  }
  return minf.f;
}

double 
NANQ(void)
{
  static int init = 0;
  static DoubleFloat nanq;
  if (! init) {
    nanq.l[0] = 0x7ff80000L;
    nanq.l[1] = 0;
    init = 1;
  }
  return nanq.f;
}
@
\eject
\begin{thebibliography}{99}
\bibitem{1} nothing
\end{thebibliography}
\end{document}