Source/SWILL/web.c

/* -----------------------------------------------------------------------------
 * web.c
 *
 *     This file implements the web-server.
 *
 * Author(s) : David Beazley (beazley@cs.uchicago.edu)
 *             Sotiria Lampoudi (slampoud@cs.uchicago.edu)
 *             Mike Sliczniak (mzsliczn@midway.uchicago.edu)
 *
 * Copyright (C) 1999-2000.  The University of Chicago
 * See the file LICENSE for information on usage and redistribution.
 * ----------------------------------------------------------------------------- */

static char cvsroot[] = "$Header: /home/pastacvs/cvs-rep/vermicelli/tot/src/SWILL-0.1/Source/SWILL/web.c,v 1.4 2005/01/28 12:24:34 dillema Exp $";

#include "swillint.h"

/*
#define __USE_MPI
#undef __USE_MPI
*/

#ifdef __USE_MPI
#include <mpi.h>
#endif

/* Server info */

       int     SwillInit    = 0;
static int     SwillSocket  = -1;
static int     SwillPort    = 0;
static String *SwillTitle   = 0;
static String *SwillDocroot = 0;
       int     SwillTimeout = SWILL_TIMEOUT;

static FILE   *SwillFile    = 0;

#ifdef __USE_MPI
static int _swill_mpi_rank, _swill_mpi_numprocs;
#endif

/* Global variables containing information about the current request */
static Hash   *http_out_headers = 0;
static String *http_uri         = 0;
static String *http_response    = 0;
static Hash   *current_request  = 0;

/* -----------------------------------------------------------------------------
 * Utility functions for setting/getting headers and form vars
 * ----------------------------------------------------------------------------- */

void swill_setheader(const char *header, const char *value) {
  Setattr(http_out_headers,header,value);
}

void swill_setresponse(const char *value) {
  if (http_response) Delete(http_response);
  http_response = NewString(value);
}

char *swill_getheader(const char *header) {
  Hash *headers;
  char temp[1024];
  char *c;
  strcpy(temp,header);
  c = temp;
  while (*c) {
    *c = tolower(*c);
    c++;
  }
  headers = Getattr(current_request,"headers");
  if (headers) {
    return GetChar(headers,temp);
  } else {
    return 0;
  }
}

char *swill_getvar(const char *name) {
  Hash *query = Getattr(current_request,"query");
  if (query) {
    return GetChar(query,name);
  }
  return 0;
}

int swill_getint(const char *name) {
  Hash *query = Getattr(current_request,"query");
  if (query) {
    return GetInt(query,name);
  }
  return 0;
}

double swill_getdouble(const char *name) {
  Hash *query = Getattr(current_request,"query");
  if (query) {
    return GetDouble(query,name);
  }
  return 0;
}

/* -----------------------------------------------------------------------------
 * swill_init()
 * ----------------------------------------------------------------------------- */

int
swill_init(int port) {
  struct sockaddr_storage servaddr;
  struct sockaddr_in6 *sin6;
  struct sockaddr_in *sin;
  int flag = 1;
  char hname[256];

  assert(!SwillInit);

  if (!SwillFile) {
    SwillFile = tmpfile();
    assert(SwillFile);
  }

  SwillSocket = -1;
  SwillPort = 0;

#ifdef __USE_MPI
  /*MPI_Init(&argc, &argv); */
  /* we don't call MPI_Init(), we expect that the host code has done it for us.
   *  --TL
   */
  MPI_Comm_size(MPI_COMM_WORLD,&_swill_mpi_numprocs);
  MPI_Comm_rank(MPI_COMM_WORLD,&_swill_mpi_rank);

#endif

  signal(SIGPIPE, SIG_IGN);

  DohEncoding("url",swill_url_encoder);
  DohEncoding("pre",swill_pre_encoder);

#ifdef __USE_MPI
  if(_swill_mpi_rank == 0) {
#endif

    /* Open up the server socket */
#ifdef USE_INET6
    SwillSocket = socket(AF_INET6, SOCK_STREAM, 0);
#else
    SwillSocket = socket(AF_INET, SOCK_STREAM, 0);
#endif

    if (SwillSocket < 0) {
      printf("swill_init: Can't create socket!\n");
      /* Maybe some kind of MPI reduce here */
      SwillInit = SwillPort = 0;
      goto init_ret;
      /*return 0; */
    }

    /* Re-use the address if possible */
    if (setsockopt(SwillSocket,SOL_SOCKET, SO_REUSEADDR,(char *)&flag,sizeof(int)) < 0) {
      perror("setsockopt");
    }

    /* Set the server address */
    bzero(&servaddr, sizeof(servaddr));
#ifdef USE_INET6
    sin6 = (struct sockaddr_in6 *) &servaddr;
    sin6->sin6_len = sizeof (struct sockaddr_in6);
    sin6->sin6_family = AF_INET6;
    sin6->sin6_port = htons(port);
    sin6->sin6_addr = in6addr_any;
#else
    sin = (struct sockaddr_in *) &servaddr;
    sin->sin_len = sizeof (struct sockaddr_in);
    sin->sin_family = AF_INET;
    sin->sin_port = htons(port);
    sin->sin_addr.s_addr = htonl(INADDR_ANY);
#endif

    /* Bind the socket to the port */
    if (bind(SwillSocket,
             (struct sockaddr *) &servaddr,
             servaddr.ss_len) < 0) {
      printf("swill_init: Can't bind to port %d!\n", port);
      perror("bind");
      /* Maybe some kind of MPI reduce here */
      SwillInit = SwillPort = 0;
      goto init_ret;
      /*      return 0; */
    }

    /* Allow, at most, 5 outstanding network connections */
    listen(SwillSocket, 5);

    /* Get port assigned to the socket */
    {
      struct  sockaddr_in  socketname;
      int     inlen = sizeof(socketname);
      if (getsockname(SwillSocket, (struct sockaddr *) &socketname,  &inlen) >= 0) {
	SwillPort = ntohs(socketname.sin_port);
      }
    }
#ifdef __USE_MPI
  } else {
    /* Need to place some initialization code here */
  }
#endif
  SwillTitle = NewString("SWILL");
  SwillDocroot = 0;
  SwillInit = 1;
  swill_security_init();
  swill_handle("info",SH(SwillListHandlers),0);

 init_ret:
#ifdef __USE_MPI
  MPI_Bcast(&SwillInit, 1,MPI_INT, 0, MPI_COMM_WORLD);
#endif
  return SwillPort;
}

/* -----------------------------------------------------------------------------
 * swill_close()
 *
 * Close the server
 * ----------------------------------------------------------------------------- */

void
swill_close() {
  if (!SwillInit) return;
  if (SwillSocket > 0) {
    close(SwillSocket);
  }
  fclose(SwillFile);
  SwillFile = 0;
  SwillSocket = 0;
  Delete(SwillTitle);
  Delete(SwillDocroot);
  SwillTitle = 0;
  SwillDocroot = 0;
  SwillInit = 0;
  swill_handler_reset();
  swill_security_reset();
}

/* -----------------------------------------------------------------------------
 * swill_title()
 *
 * Set or return the server title.
 * ----------------------------------------------------------------------------- */

char *
swill_title(const char *title) {
  if (!SwillInit) return 0;
  if (title)
    SwillTitle = NewString(title);
  return Char(SwillTitle);
}

/* -----------------------------------------------------------------------------
 * swill_directory()
 *
 * Set the document root for serving arbitrary files.
 * ----------------------------------------------------------------------------- */

char *
swill_directory(const char *pathname) {
  if (!SwillInit) return 0;
  if (pathname) {
    if (SwillDocroot) Delete(SwillDocroot);
    if (strlen(pathname)) {
      SwillDocroot = NewString(pathname);
    } else {
      SwillDocroot = 0;
    }
  }
  return SwillDocroot ? Char(SwillDocroot) : 0;
}

/* -----------------------------------------------------------------------------
 * swill_timeout()
 *
 * Send the timeout value.
 * ----------------------------------------------------------------------------- */

void
swill_timeout(int timeout) {
  SwillTimeout =  timeout;
}

/* -----------------------------------------------------------------------------
 * check_filename()
 *
 * Checks a filename to see if it is legal or not.  Does not allow any
 * path component to start with a '.'
 * ----------------------------------------------------------------------------- */

static int
check_filename(String *fn) {
  int ch;
  int state = 0;
  Seek(fn,0,SEEK_SET);
  while (1) {
    ch = Getc(fn);
    if (ch == EOF) return 1;
    if ((ch == '.') && (state)) return 0;
    if (ch == '.') state++;
    else state = 0;
  }
}

/* -----------------------------------------------------------------------------
 * swill_nbwrite()
 *
 * Non-blocking write to a socket
 * ----------------------------------------------------------------------------- */

static int
swill_nbwrite(int fd, char *buffer, int len) {
  fd_set          wset;
  struct timeval  tv;
  int             nsent = 0;
  int             retval;
  int             n;

  FD_ZERO(&wset);
  while (nsent < len) {
    FD_SET(fd,&wset);
    tv.tv_sec = SwillTimeout;
    tv.tv_usec = 0;

    retval = select(fd+1,0,&wset,0,&tv);
    if (retval <= 0) {
      /* Timeout.  We're history. */
      swill_logprintf("   Warning: write timeout!\n");
      return nsent;
    }
    n = write(fd,buffer+nsent,len-nsent);
    if (n < 0) {
      if (errno != EWOULDBLOCK) {
	return nsent;
      }
      continue;
    }
    nsent += n;
  }
  return nsent;
}

static int
swill_nbcopydata(FILE *in, int fd) {
  char buffer[16384];
  int nread;
  int total = 0;
  while (1) {
    nread = Read(in,buffer,16384);
    if (nread < 0) {
      if (errno != EINTR) {
	return total;
      }
      continue;
    }
    if (nread == 0) break;
    if (swill_nbwrite(fd,buffer,nread) != nread) {
      return total;
    }
    total += nread;
  }
}

/* -----------------------------------------------------------------------------
 * swill_dump_page()
 *
 * Dumps the raw page to the socket.
 * ----------------------------------------------------------------------------- */

static int
swill_dump_page(File *webpage, int fd) {
  String *tmp;
  String *key;
  int     nbytes;
  int     val;

  Seek(webpage, 0, SEEK_END);
  nbytes = Tell(webpage);
  Seek(webpage,0, SEEK_SET);

  /* Put the socket in non-blocking I/O mode */
  val = fcntl(fd, F_GETFL, 0);
  fcntl(fd, F_SETFL, val | O_NONBLOCK);

  tmp = NewStringf("HTTP/1.0 %s\n", http_response);

  if (swill_nbwrite(fd, Char(tmp), Len(tmp)) != Len(tmp)) {
    goto send_error;
  }
  key = Firstkey(http_out_headers);
  while (key) {
    Clear(tmp);
    Printf(tmp,"%s: %s\n", key, Getattr(http_out_headers,key));
    if (swill_nbwrite(fd, Char(tmp), Len(tmp)) != Len(tmp)) {
      goto send_error;
    }
    key = Nextkey(http_out_headers);
  }
  Clear(tmp);
  if (nbytes) {
    Printf(tmp,"Content-Length: %d\n", nbytes);
  }
  Printf(tmp,"Server: SWILL/%d.%d\n", SWILL_MAJOR_VERSION, SWILL_MINOR_VERSION);
  Printf(tmp,"Connection: close\n");
  Printf(tmp,"\n");
  if (swill_nbwrite(fd, Char(tmp), Len(tmp)) != Len(tmp)) {
    goto send_error;
  }

  swill_nbcopydata(webpage,fd);

  /* Restore flags */
  fcntl(fd, F_SETFL, val);
  if (tmp) Delete(tmp);
  return nbytes;
 send_error:
  if (tmp) Delete(tmp);
  fcntl(fd, F_SETFL,val);
  return 0;
}

/* -----------------------------------------------------------------------------
 * swill_serve_file()
 *
 * Serves a local file.  Returns -1 if unsuccessful.
 * uri is the input URL, out is the output stream, and clientfd is the
 * integer fd of the socket.
 * ----------------------------------------------------------------------------- */

static int
swill_serve_file(String *uri, File *out, int clientfd) {
  String *filename, *of;
  char *cfilename;
  FILE *f;
  int   fileok = 0;
  struct stat info;

  filename = NewString("");
  Printf(filename,"%s/%s",SwillDocroot,uri);

  if (SwillDocroot) {
    if (Strncmp(filename,SwillDocroot,Len(SwillDocroot)) == 0) {
      String *tfilename = NewString(Char(filename)+Len(SwillDocroot));
      fileok = check_filename(tfilename);
      Delete(tfilename);
    }
  } else {
    fileok = check_filename(filename);
  }

  if (fileok) {
    /* Get some statistics about the file */
  filetry:
    cfilename = (char *) Data(filename);
    if (lstat(cfilename,&info) < 0) {
      SwillFileNotFound(out,0);
      Delete(filename);
      return -1;
    }
    if (S_ISDIR(info.st_mode)) {
      /* Hmmm. Appears to be a directory.  If the directory does not have a trailing "/"
         We need to redirect the browser */
      if (cfilename[strlen(cfilename)-1] != '/') {
	swill_setresponse("301 Moved Permanently");
	of = NewString("");
	Printf(of,"http://%s/%s/", swill_getheader("host"), uri);
	swill_setheader("location",(char *) of);
	swill_setheader("Content-Type","text/html");
	Printf(out,"<h1>Moved permanently</h1>\n");
	Delete(filename);
	return -1;
      }
      Printf(filename,"%s",SWILL_DEFAULT);
      goto filetry;
    }
    f = fopen((char *)Data(filename),"r");
    if (!f) {
      SwillFileNotFound(out,0);
      Delete(filename);
      return -1;
    }
    swill_setheader("Content-Type", swill_guess_mimetype(Char(filename)));
    SetInt(http_out_headers,"Content-Length",info.st_size);

    /* Dump web-page so far */
    swill_dump_page(out,clientfd);

    {
      int val = fcntl(clientfd, F_GETFL,0);
      fcntl(clientfd, F_SETFL, val | O_NONBLOCK);
      swill_nbcopydata(f,clientfd);
      fcntl(clientfd, F_SETFL, val);
    }
    fclose(f);
    Delete(filename);
    return 0;
  } else {
    SwillFileNotFound(out,0);
    Delete(filename);
    return -1;
  }
}

/* -----------------------------------------------------------------------------
 * swill_serve_one()
 *
 * This function handles a raw http-request on a single processor. This is the
 * entry point to the server on a multiprocessor application.  Tasks performed
 * at this stage include:
 *
 *     -  Serving of simple files or directories
 *     -  User authentication
 *     -  Error messages for invalid web pages.
 *     -  Redirection.
 *
 * If the request was an error or applicable to a single processor, NULL is
 * returned.
 *
 * Otherwise, an output object is returned and some global variables are set.
 * The caller can use this to figure out how to call the handling function.
 *
 * P.S. This function is a big mess...
 * ----------------------------------------------------------------------------- */

static FILE *
swill_serve_one(struct sockaddr *clientaddr, int clientfd)
{
  Hash         *handler;
  SwillHandler whandle;
  FILE        *out = 0;
  String      *excess;
  String      *requeststring;
  Hash        *request;
  String      *method;
  String      *peerip;
  char 	      addr[INET6_ADDRSTRLEN];

  /* Compute the peer IP address */
  if (clientaddr->sa_family == AF_INET) {
    struct sockaddr_in *sin_p = (struct sockaddr_in *) clientaddr;
    peerip = NewString(inet_ntop(sin_p->sin_family, (void *) &sin_p->sin_addr,
                       addr,sizeof(addr)));
  }
#ifdef USE_INET6
  if (clientaddr->sa_family == AF_INET6) {
    struct sockaddr_in6 *sin6_p = (struct sockaddr_in6 *) clientaddr;
    peerip = NewString(inet_ntop(sin6_p->sin6_family, (void *) &sin6_p->sin6_addr,
                       addr,sizeof(addr)));
  }
#endif

  /* Implement IP filtering here */
  if (!swill_check_ip(peerip)) {
    Delete(peerip);
    return 0;
  }

  swill_logprintf("%-64s ", peerip);

  /* Read the raw HTTP request */
  if (!swill_read_rawrequest(clientfd, &requeststring, &excess)) {
    /* Bad request. Too big, malformed, etc. */
    Delete(peerip);
    swill_logprintf("Bad request\n");
    return 0;
  }

  /* Try to parse into a request */
  request = swill_parse_request_headers(requeststring);
  if (!request) {
    Delete(peerip);
    Delete(excess);
    Delete(requeststring);
    swill_logprintf("Malformed request\n");
    return 0;
  }

  /* If we made it this far, the initial HTTP request looks valid */
  Delete(requeststring);

  method = Getattr(request,"method");

  /* If a logfile is available, print some information about the request */
  {
    time_t t;
    struct tm *tms;
    char ts[256];
    t = time(NULL);
    tms = localtime(&t);
    strftime(ts,64,"[%d %b %y %H:%M:%S]", tms);
    swill_logprintf("%s %s %s\n", ts, method, Getattr(request,"uri"));
  }

  Setattr(request,"peername", peerip);
  Delete(peerip);

  /* Handle query string data here */
  if (Strcmp(method,"POST") == 0) {
    int length;
    String *posts;
    Hash   *headers;
    requeststring = Getattr(request,"request");
    headers = Getattr(request,"headers");
    Seek(requeststring, 0, SEEK_END);
    Append(requeststring,excess);            /* Add excess data */
    length = GetInt(headers,"content-length");
    if (length > 0) {
      posts = swill_read_post(clientfd,length,excess);
      if (posts) {
	if (Len(posts) > Len(excess)) {
	  Append(requeststring, Char(posts) + Len(excess));
	}
	Delete(posts);
      } else {
	Delete(excess);
	Delete(request);
	return 0;
      }
    }
  }
  Delete(excess);

  if (!swill_parse_request_data(request)) {
    Delete(request);
    return 0;
  }

  /* Request has been parsed and all form variables are set */

  /* Set global variables */
  http_uri        = Getattr(request,"uri");
  current_request = request;

  /* Create output headers */

  http_out_headers = NewHash();
  /*  Setattr(http_out_headers,"Cache-Control","no-cache"); */
  Setattr(http_out_headers,"Expires","Sat, 1 Jan 2000 00:00:00 GMT");
  Setattr(http_out_headers,"Pragma","nocache");
  swill_setresponse("200 OK");

  /* Create an output object */
  out = SwillFile;
  ftruncate(fileno(out),0);
  fseek(out,0, SEEK_SET);

  /* Check for user authorization here */
  if (!swill_checkuser()) {
    SwillAuthenticate(out,0);
    Setattr(http_out_headers,"WWW-Authenticate","Basic");
    goto handled_request;
  }

  /* Check if method is valid */
  if (!(Strcmp(method,"GET") == 0) && !(Strcmp(method,"POST") == 0)) {
      SwillUnsupported(out,0);
      goto handled_request;
  }

  /* See if there is a handler function registered for this URI */
  handler = swill_handler_lookup(http_uri);
  if (handler) {

    /* A user handler was registered.  If it is the special "info" handler or a file, we just run it here.
       Otherwise, we will return to the caller */

    /* Set default mime-type of return page */

    swill_setheader("Content-Type", GetChar(handler,"mimetype"));
    whandle = (SwillHandler) Data(Getattr(handler,"handler"));

    if (whandle) {
      /* Only serve the handler if its the special info page */
      if (Cmp(http_uri,"info") == 0) {
	(*whandle)(out,Data(Getattr(handler,"clientdata")));
	goto handled_request;
      }

      /* We actually got a valid request for something that we will
	 return to the user.  In this case, we simply return the output object */

      return out;
    } else {
      /* No callback function.  A simple file */
      FILE *f;
      char *filename;
      filename = Data(Getattr(handler,"filename"));
      f = fopen(filename,"r");
      if (!f) {
	SwillFileNotFound(out,0);
	goto handled_request;
      } else {
	/* Find out the length */
	struct stat info;
	fstat(fileno(f),&info);
	SetInt(http_out_headers,"Content-Length",info.st_size);
	swill_dump_page(out,clientfd);
	{
	  int val = fcntl(clientfd, F_GETFL,0);
	  fcntl(clientfd, F_SETFL, val | O_NONBLOCK);
	  swill_nbcopydata(f,clientfd);
	  fcntl(clientfd, F_SETFL, val);
	}
	fclose(f);
	out = 0;
	goto handled_request;
      }
    }
  }

  /* No handler registered.  Maybe we can pull something out of a directory of files */

  /* See if a document root has been set */
  if (!SwillDocroot) {
    SwillFileNotFound(out,0);
    goto handled_request;
  }
  if (swill_serve_file(http_uri,out,clientfd) >= 0) {
    out = 0;
  }

/* This code is called when the request has been handled by this function */

handled_request:

  if (out) {
    /* Dump the web-page out.  We handled it on a single processor */
    fflush(out);
    swill_dump_page(out,clientfd);
  }

  /* Cleanup */
  Delete(current_request);
  Delete(http_out_headers);
  return 0;
}

/* -----------------------------------------------------------------------------
 * swill_serve()
 * ----------------------------------------------------------------------------- */


#ifndef __USE_MPI
int
swill_serve() {
  struct sockaddr_storage clientaddr;
  int clientfd, len = sizeof(clientaddr);
  int oldstdout;

  FILE *out = 0;
  if (!SwillInit) {
    return 0;
  }

  /* Wait for a connection */
  /* This is where that DoS prevention code should go !! */
  clientfd = accept(SwillSocket, (struct sockaddr *) &clientaddr, &len);
  if (clientfd < 0) return 0;

  /* Go process request */

  out = swill_serve_one((struct sockaddr *)&clientaddr,clientfd);
  if (!out) {
    /* swill_serve_one() took care of everything.  Goodbye */
    close(clientfd);
    return 1;
  } else {
    SwillHandler  whandle;
    Hash         *handler;
    File         *of;

    handler = swill_handler_lookup(http_uri);
    assert(handler);   /* we're hosed if this is broken */

    whandle = (SwillHandler) Data(Getattr(handler,"handler"));
    assert(whandle);

    /* Note : the stdout flag is set to capture stdout */
    if (Getattr(handler,"stdout")) {
      /* This is a very sneaky horrible trick.  We swap in a new file descriptor for stdout. */
      fflush(stdout);
      oldstdout = dup(1);       /* Duplicate the file descriptor for stdout */
      /* Now dup2 the output stream onto stdout */
      dup2(fileno(out),1);
    }

    /* Call the handler */
    (*whandle)(out,Data(Getattr(handler,"clientdata")));

    if (Getattr(handler,"stdout")) {
      /* Restore the old stdout file descriptor */
      fflush(stdout);
      dup2(oldstdout,1);
      close(oldstdout);
    }
    fflush(out);
    /* Dump the web-page here */
    swill_dump_page(out,clientfd);

    /* Delete the other fields */
    Delete(current_request);
    Delete(http_out_headers);
  }
  close(clientfd);
  return 1;
}

#elif defined __USE_MPI

/* MPI version */

int
swill_serve() {
  struct sockaddr_in clientaddr;
  int clientfd, len = sizeof(clientaddr);
  int oldstdout;

  FILE *out = 0;

  String *request = 0;
  int request_len = 0;
  char *tmp_request = 0;

  if (!SwillInit) {
    return 0;
  }

  if ( _swill_mpi_rank == 0){
    /* Wait for a connection */
    /* This is where that DoS prevention code should go !! */
    clientfd = accept(SwillSocket, (struct sockaddr *) &clientaddr, &len);

    if (clientfd < 0){
      request = 0;
      goto bcast_serve;
    }

    out = swill_serve_one((struct sockaddr *)&clientaddr,clientfd);
    if (!out) {
      close(clientfd);
      request = 0;
      goto bcast_serve;
    } else {
      /* Need to regenerate a request to send to other nodes */
      request = Getattr(current_request,"request");
      request_len = Len(request);
      tmp_request = Char(request);
    }
  } /* whether NULL or not, we have a request string. --TL */

 bcast_serve:
  MPI_Bcast(&request_len, 1, MPI_INT, 0, MPI_COMM_WORLD);
  if( request_len){
    if(_swill_mpi_rank){
      tmp_request = (char *)malloc(sizeof(char) * request_len+1);
    }

    MPI_Bcast(tmp_request, request_len+1, MPI_CHAR, 0, MPI_COMM_WORLD);

    if(_swill_mpi_rank){
      request = NewString(tmp_request);
    }
    free(tmp_request);

    /* now build up the information you need to execute this;
     * this obviates the need for setting the parameters accessible to node0,
     * since it is easier for everyone to recompute them. --TL
     */

    /* This function builds the needed data structures from
       the received request string */

    if(_swill_mpi_rank){
      current_request = swill_parse_request(request);
    }
    http_out_headers = NewHash();
    http_uri         = Getattr(current_request,"uri");
    /* We need to call the handler here */
    {
      FILE *out;
      String *tmp_merged_out;
      SwillHandler  whandle;
      Hash   *handler;
      int    out_size = 0;
      int    tmp_out_size = 0;
      char   *tmp_out = 0;
      String *tmp_out_string = 0;
      int    i = 0;
      MPI_Status status;
      String *outs;

      handler = swill_handler_lookup(http_uri);
      assert(handler);   /* we're hosed if this is broken */

      whandle = (SwillHandler) Data(Getattr(handler,"handler"));
      assert(whandle);

      /* Create an output object */
      out = SwillFile;
      ftruncate(fileno(out),0);
      fseek(out,0, SEEK_SET);

      swill_setheader("Content-Type", GetChar(handler,"mimetype"));
      swill_setresponse("200 OK");

      /* Note : the stdout flag is set to capture stdout */
      if (Getattr(handler,"stdout")) {
	/* This is a very sneaky horrible trick.  We swap in a new file descriptor for stdout. */
	fflush(stdout);
	oldstdout = dup(1);       /* Duplicate the file descriptor for stdout */
	/* Now dup2 the output stream onto stdout */
	dup2(fileno(out),1);
      }

      (*whandle)(out,Data(Getattr(handler,"clientdata")));

      if (Getattr(handler,"stdout")) {
	/* Restore the old stdout file descriptor */
	fflush(stdout);
	dup2(oldstdout,1);
	close(oldstdout);
      }
      fflush(out);
      out_size = Tell(out);

      /* do fd initialization */
      if( _swill_mpi_rank == 0){
        tmp_out_string = NewString("");
        /* first dump master */
	Seek(out, 0, SEEK_SET);
	Copyto(out, tmp_out_string);
      }

      for(i = 1; i < _swill_mpi_numprocs; i ++){

        if( _swill_mpi_rank == i ){

          MPI_Send(&out_size, 1, MPI_INT, 0, i , MPI_COMM_WORLD);
	  outs = NewString("");
	  Seek(out, 0, SEEK_SET);
	  Copyto(out, outs);
          MPI_Send(Char(outs), out_size, MPI_CHAR, 0, i + 1024, MPI_COMM_WORLD);
	  Delete(outs);

        } else if(_swill_mpi_rank == 0){

          MPI_Recv(&tmp_out_size, 1, MPI_INT, i, i, MPI_COMM_WORLD, &status);
          tmp_out = (char*) malloc(sizeof(char)*tmp_out_size);
          MPI_Recv(tmp_out, tmp_out_size, MPI_CHAR, i, i + 1024,
                   MPI_COMM_WORLD, &status);
	  Write(tmp_out_string, tmp_out, tmp_out_size);
	}
      }
      if( _swill_mpi_rank == 0){
        swill_dump_page(tmp_out_string, clientfd);
	Delete(tmp_out_string);
        close(clientfd);
      }
    }
    if(!_swill_mpi_rank == 0)
      Delete(request);

    Delete(current_request);
    http_out_headers = 0;
    return 0;
  }
  else {
    /* probably just served a file
     * could also be one of a number of problems,
     * what the heck! return 0
     */
    return 0;
  }
  /* everyone return 0? --TL */
  return 0;
}

#endif

/* -----------------------------------------------------------------------------
 * swill_poll()
 *
 * See if there are any pending connections and handle them if so. Otherwise
 * return.
 * ----------------------------------------------------------------------------- */
/* non MPI version */

#ifndef __USE_MPI

int swill_poll() {
  fd_set  rset;
  struct  timeval  tv;
  int     ret;

  if (!SwillInit) return 0;

  tv.tv_sec = 0;
  tv.tv_usec = 0;

  FD_ZERO(&rset);
  FD_SET(SwillSocket,&rset);
  ret = select(SwillSocket+1,&rset,0,0,&tv);
  if (ret <= 0) {
    return 0;
  }
  if (FD_ISSET(SwillSocket,&rset)) {
    return swill_serve();
  } else {
    return 0;
  }
}

#endif

#ifdef __USE_MPI

/* MPI version of swill_poll() */

int swill_poll() {
  int serve_flag;
  fd_set  rset;
  struct  timeval  tv;
  int     ret;

  /* we use swill_poll() to reach some agreement as to whether we need to do
   * something. swill_serve() will actually do the work. --TL
   */
  if (!SwillInit) return 0;

  if(_swill_mpi_rank == 0 ){
    /* master */
    if (SwillSocket < 0) {
      serve_flag = 0;
      goto bcast_poll;
    }

    tv.tv_sec = 0;
    tv.tv_usec = 0;

    FD_ZERO(&rset);
    FD_SET(SwillSocket,&rset);
    ret = select(SwillSocket+1,&rset,0,0,&tv);
    if (ret <= 0) {
      serve_flag = 0;
      goto bcast_poll;
    }
    if (FD_ISSET(SwillSocket,&rset)) {
      serve_flag = 1;
    } else {
      serve_flag = 0;
    }
  }
 bcast_poll:
  /* rank independent: broadcast decision and act on it. --TL */
  MPI_Bcast(&serve_flag, 1, MPI_INT, 0, MPI_COMM_WORLD);
  if( serve_flag ){
    return swill_serve();
  }
  return 0;
}
#endif

void swill_netscape(const char *url) {
  char buffer[2048];
  sprintf(buffer,"netscape -remote 'openURL(http://localhost:%d/%s)'", SwillPort, url);
  system(buffer);
}