* *.c: Pervasive software-engineering-motivated rewrite of

[bpt/guile.git] / libguile / net_db.c

/* "net_db.c" network database support
 * Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */

/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
   gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */


/* Written in 1994 by Aubrey Jaffer.
 * Thanks to Hallvard.Tretteberg@si.sintef.no for inspiration and discussion.
 * Rewritten by Gary Houston to be a closer interface to the C socket library.
 * Split into net_db.c and socket.c.
 */
\f

#include <stdio.h>
#include "_scm.h"
#include "feature.h"

#include "scm_validate.h"
#include "net_db.h"

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

/* Some systems do not declare this.  Some systems do declare it, as a
   macro.  */
#ifndef h_errno
extern int h_errno;
#endif

\f

#ifndef STDC_HEADERS
int close ();
#endif /* STDC_HEADERS */

extern int inet_aton ();

GUILE_PROC (scm_inet_aton, "inet-aton", 1, 0, 0, 
            (SCM address),
"")
#define FUNC_NAME s_scm_inet_aton
{
  struct in_addr soka;

  SCM_VALIDATE_ROSTRING(1,address);
  if (SCM_SUBSTRP (address))
    address = scm_makfromstr (SCM_ROCHARS (address), SCM_ROLENGTH (address), 0);
  if (inet_aton (SCM_ROCHARS (address), &soka) == 0)
    SCM_MISC_ERROR ("bad address", SCM_EOL);
  return scm_ulong2num (ntohl (soka.s_addr));
}
#undef FUNC_NAME


GUILE_PROC (scm_inet_ntoa, "inet-ntoa", 1, 0, 0, 
            (SCM inetid),
"")
#define FUNC_NAME s_scm_inet_ntoa
{
  struct in_addr addr;
  char *s;
  SCM answer;
  addr.s_addr = htonl (SCM_NUM2ULONG (1,inetid));
  s = inet_ntoa (addr);
  answer = scm_makfromstr (s, strlen (s), 0);
  return answer;
}
#undef FUNC_NAME

#ifdef HAVE_INET_NETOF
GUILE_PROC (scm_inet_netof, "inet-netof", 1, 0, 0, 
            (SCM address),
"")
#define FUNC_NAME s_scm_inet_netof
{
  struct in_addr addr;
  addr.s_addr = htonl (SCM_NUM2ULONG (1,address));
  return scm_ulong2num ((unsigned long) inet_netof (addr));
}
#undef FUNC_NAME
#endif

#ifdef HAVE_INET_LNAOF
GUILE_PROC (scm_lnaof, "inet-lnaof", 1, 0, 0, 
            (SCM address),
"")
#define FUNC_NAME s_scm_lnaof
{
  struct in_addr addr;
  addr.s_addr = htonl (SCM_NUM2ULONG (1,address));
  return scm_ulong2num ((unsigned long) inet_lnaof (addr));
}
#undef FUNC_NAME
#endif

#ifdef HAVE_INET_MAKEADDR
GUILE_PROC (scm_inet_makeaddr, "inet-makeaddr", 2, 0, 0,
            (SCM net, SCM lna),
"")
#define FUNC_NAME s_scm_inet_makeaddr
{
  struct in_addr addr;
  unsigned long netnum;
  unsigned long lnanum;

  SCM_VALIDATE_INT_COPY(1,net,netnum);
  SCM_VALIDATE_INT_COPY(2,lna,lnanum);
  addr = inet_makeaddr (netnum, lnanum);
  return scm_ulong2num (ntohl (addr.s_addr));
}
#undef FUNC_NAME
#endif

SCM_SYMBOL (scm_host_not_found_key, "host-not-found");
SCM_SYMBOL (scm_try_again_key, "try-again");
SCM_SYMBOL (scm_no_recovery_key, "no-recovery");
SCM_SYMBOL (scm_no_data_key, "no-data");

static void scm_resolv_error (const char *subr, SCM bad_value)
{
  if (h_errno == NETDB_INTERNAL)
    {
      /* errno supposedly contains a useful value.  */
      scm_syserror (subr);
    }
  else
    {
      SCM key;
      const char *errmsg;

      switch (h_errno)
	{
	case HOST_NOT_FOUND:
	  key = scm_host_not_found_key;
	  errmsg = "Unknown host"; 
	  break;
	case TRY_AGAIN:	
	  key = scm_try_again_key;
	  errmsg = "Host name lookup failure";
	  break;
	case NO_RECOVERY:
	  key = scm_no_recovery_key;
	  errmsg = "Unknown server error"; 
	  break;
	case NO_DATA:
	  key = scm_no_data_key;
	  errmsg = "No address associated with name";
	  break;
	default:
	  scm_misc_error (subr, "Unknown resolver error", SCM_EOL);
	  errmsg = NULL;
	}

#ifdef HAVE_HSTRERROR
      errmsg = hstrerror (h_errno);
#endif
      scm_error (key, subr, errmsg, scm_cons (bad_value, SCM_EOL), SCM_EOL);
    }
}

/* Should take an extra arg for address format (will be needed for IPv6).
   Should use reentrant facilities if available.
 */

GUILE_PROC (scm_gethost, "gethost", 0, 1, 0, 
            (SCM name),
"")
#define FUNC_NAME s_scm_gethost
{
  SCM ans = scm_make_vector (SCM_MAKINUM (5), SCM_UNSPECIFIED);
  SCM *ve = SCM_VELTS (ans);
  SCM lst = SCM_EOL;
  struct hostent *entry;
  struct in_addr inad;
  char **argv;
  int i = 0;
  if (SCM_UNBNDP (name))
    {
#ifdef HAVE_GETHOSTENT
      entry = gethostent ();
#else
      entry = NULL;
#endif
      if (! entry)
	{
	  /* As far as I can tell, there's no good way to tell whether
             zero means an error or end-of-file.  The trick of
             clearing errno before calling gethostent and checking it
             afterwards doesn't cut it, because, on Linux, it seems to
             try to contact some other server (YP?) and fails, which
             is a benign failure.  */
	  return SCM_BOOL_F;
	}
    }
  else if (SCM_NIMP (name) && SCM_ROSTRINGP (name))
    {
      SCM_COERCE_SUBSTR (name);
      entry = gethostbyname (SCM_ROCHARS (name));
    }
  else
    {
      inad.s_addr = htonl (scm_num2ulong (name, (char *) SCM_ARG1, FUNC_NAME));
      entry = gethostbyaddr ((char *) &inad, sizeof (inad), AF_INET);
    }
  if (!entry)
    scm_resolv_error (FUNC_NAME, name);
  
  ve[0] = scm_makfromstr (entry->h_name, 
			  (scm_sizet) strlen (entry->h_name), 0);
  ve[1] = scm_makfromstrs (-1, entry->h_aliases);
  ve[2] = SCM_MAKINUM (entry->h_addrtype + 0L);
  ve[3] = SCM_MAKINUM (entry->h_length + 0L);
  if (sizeof (struct in_addr) != entry->h_length)
    {
      ve[4] = SCM_BOOL_F;
      return ans;
    }
  for (argv = entry->h_addr_list; argv[i]; i++);
  while (i--)
    {
      inad = *(struct in_addr *) argv[i];
      lst = scm_cons (scm_ulong2num (ntohl (inad.s_addr)), lst);
    }
  ve[4] = lst;
  return ans;
}
#undef FUNC_NAME


/* In all subsequent getMUMBLE functions, when we're called with no
   arguments, we're supposed to traverse the tables entry by entry.
   However, there doesn't seem to be any documented way to distinguish
   between end-of-table and an error; in both cases the functions
   return zero.  Gotta love Unix.  For the time being, we clear errno,
   and if we get a zero and errno is set, we signal an error.  This
   doesn't seem quite right (what if errno gets set as part of healthy
   operation?), but it seems to work okay.  We'll see.  */

#if defined(HAVE_GETNETENT) && defined(HAVE_GETNETBYNAME) && defined(HAVE_GETNETBYADDR)
GUILE_PROC (scm_getnet, "getnet", 0, 1, 0, 
            (SCM name),
"")
#define FUNC_NAME s_scm_getnet
{
  SCM ans;
  SCM *ve;
  struct netent *entry;

  ans = scm_make_vector (SCM_MAKINUM (4), SCM_UNSPECIFIED);
  ve = SCM_VELTS (ans);
  if (SCM_UNBNDP (name))
    {
      errno = 0;
      entry = getnetent ();
      if (! entry)
	{
	  if (errno)
	    SCM_SYSERROR;
	  else 
	    return SCM_BOOL_F;
	}
    }
  else if (SCM_NIMP (name) && SCM_ROSTRINGP (name))
    {
      SCM_COERCE_SUBSTR (name);
      entry = getnetbyname (SCM_ROCHARS (name));
    }
  else
    {
      unsigned long netnum;
      netnum = scm_num2ulong (name, (char *) SCM_ARG1, FUNC_NAME);
      entry = getnetbyaddr (netnum, AF_INET);
    }
  if (!entry)
    scm_syserror_msg (FUNC_NAME, "no such network %s",
		      scm_listify (name, SCM_UNDEFINED), errno);
  ve[0] = scm_makfromstr (entry->n_name, (scm_sizet) strlen (entry->n_name), 0);
  ve[1] = scm_makfromstrs (-1, entry->n_aliases);
  ve[2] = SCM_MAKINUM (entry->n_addrtype + 0L);
  ve[3] = scm_ulong2num (entry->n_net + 0L);
  return ans;
}
#undef FUNC_NAME
#endif

#ifdef HAVE_GETPROTOENT
GUILE_PROC (scm_getproto, "getproto", 0, 1, 0, 
            (SCM name),
"")
#define FUNC_NAME s_scm_getproto
{
  SCM ans;
  SCM *ve;
  struct protoent *entry;

  ans = scm_make_vector (SCM_MAKINUM (3), SCM_UNSPECIFIED);
  ve = SCM_VELTS (ans);
  if (SCM_UNBNDP (name))
    {
      errno = 0;
      entry = getprotoent ();
      if (! entry)
	{
	  if (errno)
	    SCM_SYSERROR;
	  else
	    return SCM_BOOL_F;
	}
    }
  else if (SCM_NIMP (name) && SCM_ROSTRINGP (name))
    {
      SCM_COERCE_SUBSTR (name);
      entry = getprotobyname (SCM_ROCHARS (name));
    }
  else
    {
      unsigned long protonum;
      protonum = SCM_NUM2ULONG (1,name);
      entry = getprotobynumber (protonum);
    }
  if (!entry)
    SCM_SYSERROR_MSG ("no such protocol %s",
		      scm_listify (name, SCM_UNDEFINED), errno);
  ve[0] = scm_makfromstr (entry->p_name, (scm_sizet) strlen (entry->p_name), 0);
  ve[1] = scm_makfromstrs (-1, entry->p_aliases);
  ve[2] = SCM_MAKINUM (entry->p_proto + 0L);
  return ans;
}
#undef FUNC_NAME
#endif

static SCM
scm_return_entry (struct servent *entry)
{
  SCM ans;
  SCM *ve;

  ans = scm_make_vector (SCM_MAKINUM (4), SCM_UNSPECIFIED);
  ve = SCM_VELTS (ans);
  ve[0] = scm_makfromstr (entry->s_name, (scm_sizet) strlen (entry->s_name), 0);
  ve[1] = scm_makfromstrs (-1, entry->s_aliases);
  ve[2] = SCM_MAKINUM (ntohs (entry->s_port) + 0L);
  ve[3] = scm_makfromstr (entry->s_proto, (scm_sizet) strlen (entry->s_proto), 0);
  return ans;
}

#ifdef HAVE_GETSERVENT
GUILE_PROC (scm_getserv, "getserv", 0, 2, 0,
            (SCM name, SCM proto),
"")
#define FUNC_NAME s_scm_getserv
{
  struct servent *entry;
  if (SCM_UNBNDP (name))
    {
      errno = 0;
      entry = getservent ();
      if (!entry)
	{
	  if (errno)
	    SCM_SYSERROR;
	  else
	    return SCM_BOOL_F;
	}
      return scm_return_entry (entry);
    }
  SCM_VALIDATE_ROSTRING(2,proto);
  SCM_COERCE_SUBSTR (proto);
  if (SCM_NIMP (name) && SCM_ROSTRINGP (name))
    {
      SCM_COERCE_SUBSTR (name);
      entry = getservbyname (SCM_ROCHARS (name), SCM_ROCHARS (proto));
    }
  else
    {
      SCM_VALIDATE_INT(1,name);
      entry = getservbyport (htons (SCM_INUM (name)), SCM_ROCHARS (proto));
    }
  if (!entry)
    SCM_SYSERROR_MSG("no such service %s", 
                     scm_listify (name, SCM_UNDEFINED), errno);
  return scm_return_entry (entry);
}
#undef FUNC_NAME
#endif

#if defined(HAVE_SETHOSTENT) && defined(HAVE_ENDHOSTENT)
GUILE_PROC (scm_sethost, "sethost", 0, 1, 0, 
            (SCM arg),
"")
#define FUNC_NAME s_scm_sethost
{
  if (SCM_UNBNDP (arg))
    endhostent ();
  else
    sethostent (SCM_NFALSEP (arg));
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif

#if defined(HAVE_SETNETENT) && defined(HAVE_ENDNETENT) 
GUILE_PROC (scm_setnet, "setnet", 0, 1, 0, 
            (SCM arg),
"")
#define FUNC_NAME s_scm_setnet
{
  if (SCM_UNBNDP (arg))
    endnetent ();
  else
    setnetent (SCM_NFALSEP (arg));
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif

#if defined(HAVE_SETPROTOENT) && defined(HAVE_ENDPROTOENT)
GUILE_PROC (scm_setproto, "setproto", 0, 1, 0, 
            (SCM arg),
"")
#define FUNC_NAME s_scm_setproto
{
  if (SCM_UNBNDP (arg))
    endprotoent ();
  else
    setprotoent (SCM_NFALSEP (arg));
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif

#if defined(HAVE_SETSERVENT) && defined(HAVE_ENDSERVENT)
GUILE_PROC (scm_setserv, "setserv", 0, 1, 0, 
            (SCM arg),
"")
#define FUNC_NAME s_scm_setserv
{
  if (SCM_UNBNDP (arg))
    endservent ();
  else
    setservent (SCM_NFALSEP (arg));
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif


void 
scm_init_net_db ()
{
#ifdef INADDR_ANY
  scm_sysintern ("INADDR_ANY", scm_ulong2num (INADDR_ANY));
#endif
#ifdef INADDR_BROADCAST
  scm_sysintern ("INADDR_BROADCAST", scm_ulong2num (INADDR_BROADCAST));
#endif
#ifdef INADDR_NONE
  scm_sysintern ("INADDR_NONE", scm_ulong2num (INADDR_NONE));
#endif
#ifdef INADDR_LOOPBACK
  scm_sysintern ("INADDR_LOOPBACK", scm_ulong2num (INADDR_LOOPBACK));
#endif

  scm_add_feature ("net-db");
#include "net_db.x"
}