libguile/net_db.c

   1 /* "net_db.c" network database support
   2  * Copyright (C) 1995,1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2, or (at your option)
   7  * any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this software; see the file COPYING.  If not, write to
  16  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307 USA
  18  *
  19  * As a special exception, the Free Software Foundation gives permission
  20  * for additional uses of the text contained in its release of GUILE.
  21  *
  22  * The exception is that, if you link the GUILE library with other files
  23  * to produce an executable, this does not by itself cause the
  24  * resulting executable to be covered by the GNU General Public License.
  25  * Your use of that executable is in no way restricted on account of
  26  * linking the GUILE library code into it.
  27  *
  28  * This exception does not however invalidate any other reasons why
  29  * the executable file might be covered by the GNU General Public License.
  30  *
  31  * This exception applies only to the code released by the
  32  * Free Software Foundation under the name GUILE.  If you copy
  33  * code from other Free Software Foundation releases into a copy of
  34  * GUILE, as the General Public License permits, the exception does
  35  * not apply to the code that you add in this way.  To avoid misleading
  36  * anyone as to the status of such modified files, you must delete
  37  * this exception notice from them.
  38  *
  39  * If you write modifications of your own for GUILE, it is your choice
  40  * whether to permit this exception to apply to your modifications.
  41  * If you do not wish that, delete this exception notice.  */
  42
  43 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  44    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  45
  46
  47 /* Written in 1994 by Aubrey Jaffer.
  48  * Thanks to Hallvard.Tretteberg@si.sintef.no for inspiration and discussion.
  49  * Rewritten by Gary Houston to be a closer interface to the C socket library.
  50  * Split into net_db.c and socket.c.
  51  */
  52 \f
  53
  54 #include <errno.h>
  55
  56 #include "libguile/_scm.h"
  57 #include "libguile/feature.h"
  58 #include "libguile/strings.h"
  59 #include "libguile/vectors.h"
  60
  61 #include "libguile/validate.h"
  62 #include "libguile/net_db.h"
  63
  64 #ifdef HAVE_STRING_H
  65 #include <string.h>
  66 #endif
  67
  68 #include <sys/types.h>
  69 #include <sys/socket.h>
  70 #include <netdb.h>
  71 #include <netinet/in.h>
  72 #include <arpa/inet.h>
  73
  74 #ifndef HAVE_H_ERRNO
  75 /* h_errno not found in netdb.h, maybe this will help.  */
  76 extern int h_errno;
  77 #endif
  78
  79 \f
  80
  81 SCM_SYMBOL (scm_host_not_found_key, "host-not-found");
  82 SCM_SYMBOL (scm_try_again_key, "try-again");
  83 SCM_SYMBOL (scm_no_recovery_key, "no-recovery");
  84 SCM_SYMBOL (scm_no_data_key, "no-data");
  85
  86 static void scm_resolv_error (const char *subr, SCM bad_value)
  87 {
  88 #ifdef NETDB_INTERNAL
  89   if (h_errno == NETDB_INTERNAL)
  90     {
  91       /* errno supposedly contains a useful value.  */
  92       scm_syserror (subr);
  93     }
  94   else
  95 #endif
  96     {
  97       SCM key;
  98       const char *errmsg;
  99
 100       switch (h_errno)
 101         {
 102         case HOST_NOT_FOUND:
 103           key = scm_host_not_found_key;
 104           errmsg = "Unknown host";
 105           break;
 106         case TRY_AGAIN:
 107           key = scm_try_again_key;
 108           errmsg = "Host name lookup failure";
 109           break;
 110         case NO_RECOVERY:
 111           key = scm_no_recovery_key;
 112           errmsg = "Unknown server error";
 113           break;
 114         case NO_DATA:
 115           key = scm_no_data_key;
 116           errmsg = "No address associated with name";
 117           break;
 118         default:
 119           scm_misc_error (subr, "Unknown resolver error", SCM_EOL);
 120           errmsg = NULL;
 121         }
 122
 123 #ifdef HAVE_HSTRERROR
 124       errmsg = (const char *) hstrerror (h_errno);
 125 #endif
 126       scm_error (key, subr, errmsg, scm_cons (bad_value, SCM_EOL), SCM_EOL);
 127     }
 128 }
 129
 130 /* Should take an extra arg for address format (will be needed for IPv6).
 131    Should use reentrant facilities if available.
 132  */
 133
 134 SCM_DEFINE (scm_gethost, "gethost", 0, 1, 0,
 135             (SCM host),
 136             "@deffnx procedure gethostbyname hostname\n"
 137             "@deffnx procedure gethostbyaddr address\n"
 138             "Look up a host by name or address, returning a host object.  The\n"
 139             "@code{gethost} procedure will accept either a string name or an integer\n"
 140             "address; if given no arguments, it behaves like @code{gethostent} (see\n"
 141             "below).  If a name or address is supplied but the address can not be\n"
 142             "found, an error will be thrown to one of the keys:\n"
 143             "@code{host-not-found}, @code{try-again}, @code{no-recovery} or\n"
 144             "@code{no-data}, corresponding to the equivalent @code{h_error} values.\n"
 145             "Unusual conditions may result in errors thrown to the\n"
 146             "@code{system-error} or @code{misc_error} keys.")
 147 #define FUNC_NAME s_scm_gethost
 148 {
 149   SCM ans = scm_c_make_vector (5, SCM_UNSPECIFIED);
 150   SCM *ve = SCM_VELTS (ans);
 151   SCM lst = SCM_EOL;
 152   struct hostent *entry;
 153   struct in_addr inad;
 154   char **argv;
 155   int i = 0;
 156   if (SCM_UNBNDP (host))
 157     {
 158 #ifdef HAVE_GETHOSTENT
 159       entry = gethostent ();
 160 #else
 161       entry = NULL;
 162 #endif
 163       if (! entry)
 164         {
 165           /* As far as I can tell, there's no good way to tell whether
 166              zero means an error or end-of-file.  The trick of
 167              clearing errno before calling gethostent and checking it
 168              afterwards doesn't cut it, because, on Linux, it seems to
 169              try to contact some other server (YP?) and fails, which
 170              is a benign failure.  */
 171           return SCM_BOOL_F;
 172         }
 173     }
 174   else if (SCM_STRINGP (host))
 175     {
 176       SCM_STRING_COERCE_0TERMINATION_X (host);
 177       entry = gethostbyname (SCM_STRING_CHARS (host));
 178     }
 179   else
 180     {
 181       inad.s_addr = htonl (SCM_NUM2ULONG (1, host));
 182       entry = gethostbyaddr ((char *) &inad, sizeof (inad), AF_INET);
 183     }
 184   if (!entry)
 185     scm_resolv_error (FUNC_NAME, host);
 186
 187   ve[0] = scm_makfromstr (entry->h_name,
 188                           (scm_sizet) strlen (entry->h_name), 0);
 189   ve[1] = scm_makfromstrs (-1, entry->h_aliases);
 190   ve[2] = SCM_MAKINUM (entry->h_addrtype + 0L);
 191   ve[3] = SCM_MAKINUM (entry->h_length + 0L);
 192   if (sizeof (struct in_addr) != entry->h_length)
 193     {
 194       ve[4] = SCM_BOOL_F;
 195       return ans;
 196     }
 197   for (argv = entry->h_addr_list; argv[i]; i++);
 198   while (i--)
 199     {
 200       inad = *(struct in_addr *) argv[i];
 201       lst = scm_cons (scm_ulong2num (ntohl (inad.s_addr)), lst);
 202     }
 203   ve[4] = lst;
 204   return ans;
 205 }
 206 #undef FUNC_NAME
 207
 208
 209 /* In all subsequent getMUMBLE functions, when we're called with no
 210    arguments, we're supposed to traverse the tables entry by entry.
 211    However, there doesn't seem to be any documented way to distinguish
 212    between end-of-table and an error; in both cases the functions
 213    return zero.  Gotta love Unix.  For the time being, we clear errno,
 214    and if we get a zero and errno is set, we signal an error.  This
 215    doesn't seem quite right (what if errno gets set as part of healthy
 216    operation?), but it seems to work okay.  We'll see.  */
 217
 218 #if defined(HAVE_GETNETENT) && defined(HAVE_GETNETBYNAME) && defined(HAVE_GETNETBYADDR)
 219 SCM_DEFINE (scm_getnet, "getnet", 0, 1, 0,
 220             (SCM net),
 221             "@deffnx procedure getnetbyname net-name\n"
 222             "@deffnx procedure getnetbyaddr net-number\n"
 223             "Look up a network by name or net number in the network database.  The\n"
 224             "@var{net-name} argument must be a string, and the @var{net-number}\n"
 225             "argument must be an integer.  @code{getnet} will accept either type of\n"
 226             "argument, behaving like @code{getnetent} (see below) if no arguments are\n"
 227             "given.")
 228 #define FUNC_NAME s_scm_getnet
 229 {
 230   SCM ans;
 231   SCM *ve;
 232   struct netent *entry;
 233
 234   ans = scm_c_make_vector (4, SCM_UNSPECIFIED);
 235   ve = SCM_VELTS (ans);
 236   if (SCM_UNBNDP (net))
 237     {
 238       entry = getnetent ();
 239       if (! entry)
 240         {
 241           /* There's no good way to tell whether zero means an error
 242              or end-of-file, so we always return #f.  See `gethost'
 243              for details. */
 244           return SCM_BOOL_F;
 245         }
 246     }
 247   else if (SCM_STRINGP (net))
 248     {
 249       SCM_STRING_COERCE_0TERMINATION_X (net);
 250       entry = getnetbyname (SCM_STRING_CHARS (net));
 251     }
 252   else
 253     {
 254       unsigned long netnum;
 255       netnum = SCM_NUM2ULONG (1, net);
 256       entry = getnetbyaddr (netnum, AF_INET);
 257     }
 258   if (!entry)
 259     SCM_SYSERROR_MSG ("no such network ~A", SCM_LIST1 (net), errno);
 260   ve[0] = scm_makfromstr (entry->n_name, (scm_sizet) strlen (entry->n_name), 0);
 261   ve[1] = scm_makfromstrs (-1, entry->n_aliases);
 262   ve[2] = SCM_MAKINUM (entry->n_addrtype + 0L);
 263   ve[3] = scm_ulong2num (entry->n_net + 0L);
 264   return ans;
 265 }
 266 #undef FUNC_NAME
 267 #endif
 268
 269 #ifdef HAVE_GETPROTOENT
 270 SCM_DEFINE (scm_getproto, "getproto", 0, 1, 0,
 271             (SCM protocol),
 272             "@deffnx procedure getprotobyname name\n"
 273             "@deffnx procedure getprotobynumber number\n"
 274             "Look up a network protocol by name or by number.  @code{getprotobyname}\n"
 275             "takes a string argument, and @code{getprotobynumber} takes an integer\n"
 276             "argument.  @code{getproto} will accept either type, behaving like\n"
 277             "@code{getprotoent} (see below) if no arguments are supplied.")
 278 #define FUNC_NAME s_scm_getproto
 279 {
 280   SCM ans;
 281   SCM *ve;
 282   struct protoent *entry;
 283
 284   ans = scm_c_make_vector (3, SCM_UNSPECIFIED);
 285   ve = SCM_VELTS (ans);
 286   if (SCM_UNBNDP (protocol))
 287     {
 288       entry = getprotoent ();
 289       if (! entry)
 290         {
 291           /* There's no good way to tell whether zero means an error
 292              or end-of-file, so we always return #f.  See `gethost'
 293              for details. */
 294           return SCM_BOOL_F;
 295         }
 296     }
 297   else if (SCM_STRINGP (protocol))
 298     {
 299       SCM_STRING_COERCE_0TERMINATION_X (protocol);
 300       entry = getprotobyname (SCM_STRING_CHARS (protocol));
 301     }
 302   else
 303     {
 304       unsigned long protonum;
 305       protonum = SCM_NUM2ULONG (1, protocol);
 306       entry = getprotobynumber (protonum);
 307     }
 308   if (!entry)
 309     SCM_SYSERROR_MSG ("no such protocol ~A", SCM_LIST1 (protocol), errno);
 310   ve[0] = scm_makfromstr (entry->p_name, (scm_sizet) strlen (entry->p_name), 0);
 311   ve[1] = scm_makfromstrs (-1, entry->p_aliases);
 312   ve[2] = SCM_MAKINUM (entry->p_proto + 0L);
 313   return ans;
 314 }
 315 #undef FUNC_NAME
 316 #endif
 317
 318 static SCM
 319 scm_return_entry (struct servent *entry)
 320 {
 321   SCM ans;
 322   SCM *ve;
 323
 324   ans = scm_c_make_vector (4, SCM_UNSPECIFIED);
 325   ve = SCM_VELTS (ans);
 326   ve[0] = scm_makfromstr (entry->s_name, (scm_sizet) strlen (entry->s_name), 0);
 327   ve[1] = scm_makfromstrs (-1, entry->s_aliases);
 328   ve[2] = SCM_MAKINUM (ntohs (entry->s_port) + 0L);
 329   ve[3] = scm_makfromstr (entry->s_proto, (scm_sizet) strlen (entry->s_proto), 0);
 330   return ans;
 331 }
 332
 333 #ifdef HAVE_GETSERVENT
 334 SCM_DEFINE (scm_getserv, "getserv", 0, 2, 0,
 335             (SCM name, SCM protocol),
 336             "@deffnx procedure getservbyname name protocol\n"
 337             "@deffnx procedure getservbyport port protocol\n"
 338             "Look up a network service by name or by service number, and return a\n"
 339             "network service object.  The @var{protocol} argument specifies the name\n"
 340             "of the desired protocol; if the protocol found in the network service\n"
 341             "database does not match this name, a system error is signalled.\n\n"
 342             "The @code{getserv} procedure will take either a service name or number\n"
 343             "as its first argument; if given no arguments, it behaves like\n"
 344             "@code{getservent} (see below).")
 345 #define FUNC_NAME s_scm_getserv
 346 {
 347   struct servent *entry;
 348   if (SCM_UNBNDP (name))
 349     {
 350       entry = getservent ();
 351       if (!entry)
 352         {
 353           /* There's no good way to tell whether zero means an error
 354              or end-of-file, so we always return #f.  See `gethost'
 355              for details. */
 356           return SCM_BOOL_F;
 357         }
 358       return scm_return_entry (entry);
 359     }
 360   SCM_VALIDATE_STRING (2, protocol);
 361   SCM_STRING_COERCE_0TERMINATION_X (protocol);
 362   if (SCM_STRINGP (name))
 363     {
 364       SCM_STRING_COERCE_0TERMINATION_X (name);
 365       entry = getservbyname (SCM_STRING_CHARS (name), SCM_STRING_CHARS (protocol));
 366     }
 367   else
 368     {
 369       SCM_VALIDATE_INUM (1,name);
 370       entry = getservbyport (htons (SCM_INUM (name)), SCM_STRING_CHARS (protocol));
 371     }
 372   if (!entry)
 373     SCM_SYSERROR_MSG("no such service ~A", SCM_LIST1 (name), errno);
 374   return scm_return_entry (entry);
 375 }
 376 #undef FUNC_NAME
 377 #endif
 378
 379 #if defined(HAVE_SETHOSTENT) && defined(HAVE_ENDHOSTENT)
 380 SCM_DEFINE (scm_sethost, "sethost", 0, 1, 0,
 381             (SCM stayopen),
 382             "If @var{stayopen} is omitted, this is equivalent to @code{endhostent}.\n"
 383             "Otherwise it is equivalent to @code{sethostent stayopen}.")
 384 #define FUNC_NAME s_scm_sethost
 385 {
 386   if (SCM_UNBNDP (stayopen))
 387     endhostent ();
 388   else
 389     sethostent (SCM_NFALSEP (stayopen));
 390   return SCM_UNSPECIFIED;
 391 }
 392 #undef FUNC_NAME
 393 #endif
 394
 395 #if defined(HAVE_SETNETENT) && defined(HAVE_ENDNETENT)
 396 SCM_DEFINE (scm_setnet, "setnet", 0, 1, 0,
 397             (SCM stayopen),
 398             "If @var{stayopen} is omitted, this is equivalent to @code{endnetent}.\n"
 399             "Otherwise it is equivalent to @code{setnetent stayopen}.")
 400 #define FUNC_NAME s_scm_setnet
 401 {
 402   if (SCM_UNBNDP (stayopen))
 403     endnetent ();
 404   else
 405     setnetent (SCM_NFALSEP (stayopen));
 406   return SCM_UNSPECIFIED;
 407 }
 408 #undef FUNC_NAME
 409 #endif
 410
 411 #if defined(HAVE_SETPROTOENT) && defined(HAVE_ENDPROTOENT)
 412 SCM_DEFINE (scm_setproto, "setproto", 0, 1, 0,
 413             (SCM stayopen),
 414             "If @var{stayopen} is omitted, this is equivalent to @code{endprotoent}.\n"
 415             "Otherwise it is equivalent to @code{setprotoent stayopen}.")
 416 #define FUNC_NAME s_scm_setproto
 417 {
 418   if (SCM_UNBNDP (stayopen))
 419     endprotoent ();
 420   else
 421     setprotoent (SCM_NFALSEP (stayopen));
 422   return SCM_UNSPECIFIED;
 423 }
 424 #undef FUNC_NAME
 425 #endif
 426
 427 #if defined(HAVE_SETSERVENT) && defined(HAVE_ENDSERVENT)
 428 SCM_DEFINE (scm_setserv, "setserv", 0, 1, 0,
 429             (SCM stayopen),
 430             "If @var{stayopen} is omitted, this is equivalent to @code{endservent}.\n"
 431             "Otherwise it is equivalent to @code{setservent stayopen}.")
 432 #define FUNC_NAME s_scm_setserv
 433 {
 434   if (SCM_UNBNDP (stayopen))
 435     endservent ();
 436   else
 437     setservent (SCM_NFALSEP (stayopen));
 438   return SCM_UNSPECIFIED;
 439 }
 440 #undef FUNC_NAME
 441 #endif
 442
 443
 444 void
 445 scm_init_net_db ()
 446 {
 447   scm_add_feature ("net-db");
 448 #ifndef SCM_MAGIC_SNARFER
 449 #include "libguile/net_db.x"
 450 #endif
 451 }
 452
 453 /*
 454   Local Variables:
 455   c-file-style: "gnu"
 456   End:
 457 */