gcc/ada/socket.c

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT COMPILER COMPONENTS                         *
   4  *                                                                          *
   5  *                               S O C K E T                                *
   6  *                                                                          *
   7  *                          C Implementation File                           *
   8  *                                                                          *
   9  *          Copyright (C) 2003-2020, Free Software Foundation, Inc.         *
  10  *                                                                          *
  11  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  12  * terms of the  GNU General Public License as published  by the Free Soft- *
  13  * ware  Foundation;  either version 3,  or (at your option) any later ver- *
  14  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  15  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  16  * or FITNESS FOR A PARTICULAR PURPOSE.                                     *
  17  *                                                                          *
  18  * As a special exception under Section 7 of GPL version 3, you are granted *
  19  * additional permissions described in the GCC Runtime Library Exception,   *
  20  * version 3.1, as published by the Free Software Foundation.               *
  21  *                                                                          *
  22  * You should have received a copy of the GNU General Public License and    *
  23  * a copy of the GCC Runtime Library Exception along with this program;     *
  24  * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    *
  25  * <http://www.gnu.org/licenses/>.                                          *
  26  *                                                                          *
  27  * GNAT was originally developed  by the GNAT team at  New York University. *
  28  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  29  *                                                                          *
  30  ****************************************************************************/
  31
  32 /*  This file provides a portable binding to the sockets API                */
  33
  34 #define ATTRIBUTE_UNUSED __attribute__((unused))
  35
  36 /* Ensure access to errno is thread safe.  */
  37 #ifndef _REENTRANT
  38 #define _REENTRANT
  39 #endif
  40 #define _THREAD_SAFE
  41
  42 #include "gsocket.h"
  43
  44 #if defined (__FreeBSD__) || defined (__DragonFly__) \
  45  || defined (__NetBSD__) || defined (__OpenBSD__)
  46 typedef unsigned int IOCTL_Req_T;
  47 #else
  48 typedef int IOCTL_Req_T;
  49 #endif
  50
  51 #if defined(HAVE_SOCKETS)
  52
  53 /* Include all the necessary system-specific headers and define the
  54  * necessary macros (shared with gen-oscons).
  55  */
  56
  57 #if !defined(SO_NOSIGPIPE) && !defined (MSG_NOSIGNAL)
  58 #include <signal.h>
  59 #endif
  60 /* Required if we will be calling signal() in __gnat_disable_all_sigpipes() */
  61
  62 #include "raise.h"
  63 /* Required for __gnat_malloc() */
  64
  65 #include <string.h>
  66 /* Required for memcpy() */
  67
  68 extern void __gnat_disable_sigpipe (int fd);
  69 extern void __gnat_disable_all_sigpipes (void);
  70 extern int  __gnat_create_signalling_fds (int *fds);
  71 extern int  __gnat_read_signalling_fd (int rsig);
  72 extern int  __gnat_write_signalling_fd (int wsig);
  73 extern void  __gnat_close_signalling_fd (int sig);
  74 extern void __gnat_last_socket_in_set (fd_set *, int *);
  75 extern void __gnat_get_socket_from_set (fd_set *, int *, int *);
  76 extern void __gnat_insert_socket_in_set (fd_set *, int);
  77 extern int __gnat_is_socket_in_set (fd_set *, int);
  78 extern fd_set *__gnat_new_socket_set (fd_set *);
  79 extern void __gnat_remove_socket_from_set (fd_set *, int);
  80 extern void __gnat_reset_socket_set (fd_set *);
  81 extern int  __gnat_get_h_errno (void);
  82 extern int  __gnat_socket_ioctl (int, IOCTL_Req_T, int *);
  83
  84 extern char * __gnat_servent_s_name (struct servent *);
  85 extern char * __gnat_servent_s_alias (struct servent *, int index);
  86 extern unsigned short __gnat_servent_s_port (struct servent *);
  87 extern char * __gnat_servent_s_proto (struct servent *);
  88
  89 extern char * __gnat_hostent_h_name (struct hostent *);
  90 extern char * __gnat_hostent_h_alias (struct hostent *, int);
  91 extern int __gnat_hostent_h_addrtype (struct hostent *);
  92 extern int __gnat_hostent_h_length (struct hostent *);
  93 extern char * __gnat_hostent_h_addr (struct hostent *, int);
  94
  95 extern int __gnat_getaddrinfo(
  96   const char *node,
  97   const char *service,
  98   const struct addrinfo *hints,
  99   struct addrinfo **res);
 100 int __gnat_getnameinfo(
 101   const struct sockaddr *sa, socklen_t salen,
 102   char *host, size_t hostlen,
 103   char *serv, size_t servlen, int flags);
 104 extern void __gnat_freeaddrinfo(struct addrinfo *res);
 105 extern const char * __gnat_gai_strerror(int errcode);
 106
 107 #ifndef HAVE_INET_PTON
 108 extern int  __gnat_inet_pton (int, const char *, void *);
 109 #endif
 110
 111 #ifndef HAVE_INET_NTOP
 112 extern const char *
 113 __gnat_inet_ntop(int, const void *, char *, socklen_t);
 114 #endif
 115
 116 /* Disable the sending of SIGPIPE for writes on a broken stream */
 117
 118 void
 119 __gnat_disable_sigpipe (int fd ATTRIBUTE_UNUSED)
 120 {
 121 #ifdef SO_NOSIGPIPE
 122   int val = 1;
 123   (void) setsockopt (fd, SOL_SOCKET, SO_NOSIGPIPE, &val, sizeof val);
 124 #endif
 125 }
 126
 127 void
 128 __gnat_disable_all_sigpipes (void)
 129 {
 130 #if !defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL) && defined(SIGPIPE)
 131   (void) signal (SIGPIPE, SIG_IGN);
 132 #endif
 133 }
 134
 135 #if defined (_WIN32) || defined (__vxworks)
 136 /*
 137  * Signalling FDs operations are implemented in Ada for these platforms
 138  * (see subunit GNAT.Sockets.Thin.Signalling_Fds).
 139  */
 140 #else
 141 /*
 142  * Create a pair of connected file descriptors fds[0] and fds[1] used for
 143  * signalling by a Selector object. fds[0] is the read end, and fds[1] the
 144  * write end.
 145  */
 146 int
 147 __gnat_create_signalling_fds (int *fds) {
 148   return pipe (fds);
 149 }
 150
 151 /*
 152  * Read one byte of data from rsig, the read end of a pair of signalling fds
 153  * created by __gnat_create_signalling_fds.
 154  */
 155 int
 156 __gnat_read_signalling_fd (int rsig) {
 157   char c;
 158   return read (rsig, &c, 1);
 159 }
 160
 161 /*
 162  * Write one byte of data to wsig, the write end of a pair of signalling fds
 163  * created by __gnat_create_signalling_fds.
 164  */
 165 int
 166 __gnat_write_signalling_fd (int wsig) {
 167   char c = 0;
 168   return write (wsig, &c, 1);
 169 }
 170
 171 /*
 172  * Close one end of a pair of signalling fds
 173  */
 174 void
 175 __gnat_close_signalling_fd (int sig) {
 176   (void) close (sig);
 177 }
 178 #endif
 179
 180 /*
 181  * Handling of gethostbyname, gethostbyaddr, getservbyname and getservbyport
 182  * =========================================================================
 183  *
 184  * This module exposes __gnat_getXXXbyYYY operations with the same signature
 185  * as the reentrant variant getXXXbyYYY_r.
 186  *
 187  * On platforms where getXXXbyYYY is intrinsically reentrant, the provided user
 188  * buffer argument is ignored.
 189  *
 190  * When getXXXbyYYY is not reentrant but getXXXbyYYY_r exists, the latter is
 191  * used, and the provided buffer argument must point to a valid, thread-local
 192  * buffer (usually on the caller's stack).
 193  *
 194  * When getXXXbyYYY is not reentrant and no reentrant getXXXbyYYY_r variant
 195  * is available, the non-reentrant getXXXbyYYY is called, the provided user
 196  * buffer is ignored, and the caller is expected to take care of mutual
 197  * exclusion.
 198  */
 199
 200 #ifdef HAVE_GETxxxBYyyy_R
 201 int
 202 __gnat_gethostbyname (const char *name,
 203   struct hostent *ret, char *buf, size_t buflen,
 204   int *h_errnop)
 205 {
 206   struct hostent *rh;
 207   int ri;
 208
 209 #if defined(__linux__) || defined(__GLIBC__) || defined(__rtems__)
 210   (void) gethostbyname_r (name, ret, buf, buflen, &rh, h_errnop);
 211 #else
 212   rh = gethostbyname_r (name, ret, buf, buflen, h_errnop);
 213 #endif
 214   ri = (rh == NULL) ? -1 : 0;
 215   return ri;
 216 }
 217
 218 int
 219 __gnat_gethostbyaddr (const char *addr, int len, int type,
 220   struct hostent *ret, char *buf, size_t buflen,
 221   int *h_errnop)
 222 {
 223   struct hostent *rh;
 224   int ri;
 225
 226 #if defined(__linux__) || defined(__GLIBC__) || defined(__rtems__)
 227   (void) gethostbyaddr_r (addr, len, type, ret, buf, buflen, &rh, h_errnop);
 228 #else
 229   rh = gethostbyaddr_r (addr, len, type, ret, buf, buflen, h_errnop);
 230 #endif
 231   ri = (rh == NULL) ? -1 : 0;
 232   return ri;
 233 }
 234
 235 int
 236 __gnat_getservbyname (const char *name, const char *proto,
 237   struct servent *ret, char *buf, size_t buflen)
 238 {
 239   struct servent *rh;
 240   int ri;
 241
 242 #if defined(__linux__) || defined(__GLIBC__) || defined(__rtems__)
 243   (void) getservbyname_r (name, proto, ret, buf, buflen, &rh);
 244 #else
 245   rh = getservbyname_r (name, proto, ret, buf, buflen);
 246 #endif
 247   ri = (rh == NULL) ? -1 : 0;
 248   return ri;
 249 }
 250
 251 int
 252 __gnat_getservbyport (int port, const char *proto,
 253   struct servent *ret, char *buf, size_t buflen)
 254 {
 255   struct servent *rh;
 256   int ri;
 257
 258 #if defined(__linux__) || defined(__GLIBC__) || defined(__rtems__)
 259   (void) getservbyport_r (port, proto, ret, buf, buflen, &rh);
 260 #else
 261   rh = getservbyport_r (port, proto, ret, buf, buflen);
 262 #endif
 263   ri = (rh == NULL) ? -1 : 0;
 264   return ri;
 265 }
 266 #elif defined (__vxworks)
 267 static char vxw_h_name[MAXHOSTNAMELEN + 1];
 268 static char *vxw_h_aliases[1] = { NULL };
 269 static int vxw_h_addr;
 270 static char *vxw_h_addr_list[2] = { (char*) &vxw_h_addr, NULL };
 271
 272 int
 273 __gnat_gethostbyname (const char *name,
 274   struct hostent *ret, char *buf, size_t buflen,
 275   int *h_errnop)
 276 {
 277   vxw_h_addr = hostGetByName (name);
 278   if (vxw_h_addr == ERROR) {
 279     *h_errnop = __gnat_get_h_errno ();
 280     return -1;
 281   }
 282   ret->h_name      = name;
 283   ret->h_aliases   = &vxw_h_aliases;
 284   ret->h_addrtype  = AF_INET;
 285   ret->h_length    = 4;
 286   ret->h_addr_list = &vxw_h_addr_list;
 287   return 0;
 288 }
 289
 290 int
 291 __gnat_gethostbyaddr (const char *addr, int len, int type,
 292   struct hostent *ret, char *buf, size_t buflen,
 293   int *h_errnop)
 294 {
 295   if (type != AF_INET) {
 296     *h_errnop = EAFNOSUPPORT;
 297     return -1;
 298   }
 299
 300   if (addr == NULL || len != 4) {
 301     *h_errnop = EINVAL;
 302     return -1;
 303   }
 304
 305   if (hostGetByAddr (*(int*)addr, &vxw_h_name) != OK) {
 306     *h_errnop = __gnat_get_h_errno ();
 307     return -1;
 308   }
 309
 310   vxw_h_addr       = addr;
 311
 312   ret->h_name      = &vxw_h_name;
 313   ret->h_aliases   = &vxw_h_aliases;
 314   ret->h_addrtype  = AF_INET;
 315   ret->h_length    = 4;
 316   ret->h_addr_list = &vxw_h_addr_list;
 317 }
 318
 319 int
 320 __gnat_getservbyname (const char *name, const char *proto,
 321   struct servent *ret, char *buf, size_t buflen)
 322 {
 323   /* Not available under VxWorks */
 324   return -1;
 325 }
 326
 327 int
 328 __gnat_getservbyport (int port, const char *proto,
 329   struct servent *ret, char *buf, size_t buflen)
 330 {
 331   /* Not available under VxWorks */
 332   return -1;
 333 }
 334 #else
 335 int
 336 __gnat_gethostbyname (const char *name, struct hostent *ret,
 337   char *buf ATTRIBUTE_UNUSED, size_t buflen ATTRIBUTE_UNUSED,
 338   int *h_errnop)
 339 {
 340   struct hostent *rh;
 341   rh = gethostbyname (name);
 342   if (rh == NULL) {
 343     *h_errnop = __gnat_get_h_errno ();
 344     return -1;
 345   }
 346   *ret = *rh;
 347   *h_errnop = 0;
 348   return 0;
 349 }
 350
 351 int
 352 __gnat_gethostbyaddr (const char *addr, int len, int type, struct hostent *ret,
 353   char *buf ATTRIBUTE_UNUSED, size_t buflen ATTRIBUTE_UNUSED,
 354   int *h_errnop)
 355 {
 356   struct hostent *rh;
 357   rh = gethostbyaddr (addr, len, type);
 358   if (rh == NULL) {
 359     *h_errnop = __gnat_get_h_errno ();
 360     return -1;
 361   }
 362   *ret = *rh;
 363   *h_errnop = 0;
 364   return 0;
 365 }
 366
 367 int
 368 __gnat_getservbyname (const char *name, const char *proto, struct servent *ret,
 369   char *buf ATTRIBUTE_UNUSED, size_t buflen ATTRIBUTE_UNUSED)
 370 {
 371   struct servent *rh;
 372   rh = getservbyname (name, proto);
 373   if (rh == NULL)
 374     return -1;
 375   *ret = *rh;
 376   return 0;
 377 }
 378
 379 int
 380 __gnat_getservbyport (int port, const char *proto, struct servent *ret,
 381   char *buf ATTRIBUTE_UNUSED, size_t buflen ATTRIBUTE_UNUSED)
 382 {
 383   struct servent *rh;
 384   rh = getservbyport (port, proto);
 385   if (rh == NULL)
 386     return -1;
 387   *ret = *rh;
 388   return 0;
 389 }
 390 #endif
 391
 392 /* Find the largest socket in the socket set SET. This is needed for
 393    `select'.  LAST is the maximum value for the largest socket. This hint is
 394    used to avoid scanning very large socket sets.  On return, LAST is the
 395    actual largest socket in the socket set. */
 396
 397 void
 398 __gnat_last_socket_in_set (fd_set *set, int *last)
 399 {
 400   int l;
 401   l = -1;
 402
 403 #ifdef _WIN32
 404   /* More efficient method for NT. */
 405   for (unsigned int s = 0; s < set->fd_count; s++)
 406     if ((int) set->fd_array[s] > l)
 407       l = set->fd_array[s];
 408
 409 #else
 410
 411   for (int s = *last; s != -1; s--)
 412     if (FD_ISSET (s, set))
 413       {
 414         l = s;
 415         break;
 416       }
 417 #endif
 418
 419   *last = l;
 420 }
 421
 422 /* Get last socket and remove it from the socket set SET.  LAST is the
 423    maximum value of the largest socket.  This hint is used to avoid scanning
 424    very large socket sets.  On return, LAST is set to the actual largest
 425    socket in the socket set. */
 426
 427 void
 428 __gnat_get_socket_from_set (fd_set *set, int *last, int *socket)
 429 {
 430   *socket = *last;
 431   FD_CLR (*socket, set);
 432   __gnat_last_socket_in_set (set, last);
 433 }
 434
 435 /* Insert SOCKET in the socket set SET. */
 436
 437 void
 438 __gnat_insert_socket_in_set (fd_set *set, int socket)
 439 {
 440   FD_SET (socket, set);
 441 }
 442
 443 /* Check whether a given SOCKET is in the socket set SET. */
 444
 445 int
 446 __gnat_is_socket_in_set (fd_set *set, int socket)
 447 {
 448   return FD_ISSET (socket, set);
 449 }
 450
 451 /* Remove SOCKET from the socket set SET. */
 452
 453 void
 454 __gnat_remove_socket_from_set (fd_set *set, int socket)
 455 {
 456   FD_CLR (socket, set);
 457 }
 458
 459 /* Reset SET */
 460 void
 461 __gnat_reset_socket_set (fd_set *set)
 462 {
 463   FD_ZERO (set);
 464 }
 465
 466 /* Get the value of the last host error */
 467
 468 int
 469 __gnat_get_h_errno (void) {
 470 #ifdef __vxworks
 471   int vxw_errno = errno;
 472
 473   switch (vxw_errno) {
 474     case 0:
 475       return 0;
 476
 477 #ifdef S_hostLib_HOST_NOT_FOUND
 478     case S_hostLib_HOST_NOT_FOUND:
 479 #endif
 480     case S_hostLib_UNKNOWN_HOST:
 481       return HOST_NOT_FOUND;
 482
 483 #ifdef S_hostLib_TRY_AGAIN
 484     case S_hostLib_TRY_AGAIN:
 485       return TRY_AGAIN;
 486 #endif
 487
 488 #ifdef S_hostLib_NO_RECOVERY
 489     case S_hostLib_NO_RECOVERY:
 490 #endif
 491 #ifdef S_hostLib_NETDB_INTERNAL
 492     case S_hostLib_NETDB_INTERNAL:
 493 #endif
 494     case S_hostLib_INVALID_PARAMETER:
 495       return NO_RECOVERY;
 496
 497     default:
 498       return -1;
 499   }
 500
 501 #elif defined (__rtems__)
 502   /* At this stage in the tool build, no networking .h files are available.
 503    * Newlib does not provide networking .h files and RTEMS is not built yet.
 504    * So we need to explicitly extern h_errno to access it.
 505    */
 506   extern int h_errno;
 507   return h_errno;
 508
 509 #else
 510   return h_errno;
 511 #endif
 512 }
 513
 514 /* Wrapper for ioctl(2), which is a variadic function */
 515
 516 int
 517 __gnat_socket_ioctl (int fd, IOCTL_Req_T req, int *arg) {
 518 #if defined (_WIN32)
 519   return ioctlsocket (fd, req, (unsigned long *)arg);
 520 #elif defined (__APPLE__)
 521   /*
 522    * On Darwin, req is an unsigned long, and we want to convert without sign
 523    * extension to get the proper bit pattern in the case of a 64 bit kernel.
 524    */
 525   return ioctl (fd, (unsigned int) req, arg);
 526 #else
 527   return ioctl (fd, req, arg);
 528 #endif
 529 }
 530
 531 #ifndef HAVE_INET_PTON
 532
 533 int
 534 __gnat_inet_pton (int af, const char *src, void *dst) {
 535   switch (af) {
 536 #if defined (_WIN32) && defined (AF_INET6)
 537     case AF_INET6:
 538 #endif
 539     case AF_INET:
 540       break;
 541     default:
 542       errno = EAFNOSUPPORT;
 543       return -1;
 544   }
 545
 546 #if defined (__vxworks)
 547   return (inet_aton (src, dst) == OK);
 548
 549 #elif defined (_WIN32)
 550   struct sockaddr_storage ss;
 551   int sslen = sizeof ss;
 552   int rc;
 553
 554   ss.ss_family = af;
 555   rc = WSAStringToAddressA ((char *)src, af, NULL, (struct sockaddr *)&ss,
 556                             &sslen);
 557   if (rc == 0) {
 558     switch (af) {
 559       case AF_INET:
 560         *(struct in_addr *)dst = ((struct sockaddr_in *)&ss)->sin_addr;
 561         break;
 562 #ifdef AF_INET6
 563       case AF_INET6:
 564         *(struct in6_addr *)dst = ((struct sockaddr_in6 *)&ss)->sin6_addr;
 565         break;
 566 #endif
 567     }
 568   }
 569   return (rc == 0);
 570
 571 #elif defined (__hpux__)
 572   in_addr_t addr;
 573   int rc = -1;
 574
 575   if (src == NULL || dst == NULL) {
 576     errno = EINVAL;
 577
 578   } else if (!strcmp (src, "255.255.255.255")) {
 579     addr = 0xffffffff;
 580     rc = 1;
 581
 582   } else {
 583     addr = inet_addr (src);
 584     rc = (addr != 0xffffffff);
 585   }
 586   if (rc == 1) {
 587     *(in_addr_t *)dst = addr;
 588   }
 589   return rc;
 590 #endif
 591 }
 592 #endif
 593
 594 #ifndef HAVE_INET_NTOP
 595
 596 const char *
 597 __gnat_inet_ntop(int af, const void *src, char *dst, socklen_t size)
 598 {
 599 #ifdef _WIN32
 600   struct sockaddr_storage ss;
 601   int sslen = sizeof ss;
 602   memset(&ss, 0, sslen);
 603   ss.ss_family = af;
 604
 605   switch (af) {
 606     case AF_INET6:
 607       ((struct sockaddr_in6 *)&ss)->sin6_addr = *(struct in6_addr *)src;
 608       break;
 609     case AF_INET:
 610       ((struct sockaddr_in *)&ss)->sin_addr = *(struct in_addr *)src;
 611       break;
 612     default:
 613       errno = EAFNOSUPPORT;
 614       return NULL;
 615   }
 616
 617   DWORD sz = size;
 618
 619   if (WSAAddressToStringA((struct sockaddr*)&ss, sslen, 0, dst, &sz) != 0) {
 620      return NULL;
 621   }
 622   return dst;
 623 #else
 624   return NULL;
 625 #endif
 626 }
 627 #endif
 628
 629 /*
 630  * Accessor functions for struct hostent.
 631  */
 632
 633 char * __gnat_hostent_h_name (struct hostent * h) {
 634   return h->h_name;
 635 }
 636
 637 char * __gnat_hostent_h_alias (struct hostent * h, int index) {
 638   return h->h_aliases[index];
 639 }
 640
 641 int __gnat_hostent_h_addrtype (struct hostent * h) {
 642   return h->h_addrtype;
 643 }
 644
 645 int __gnat_hostent_h_length (struct hostent * h) {
 646   return h->h_length;
 647 }
 648
 649 char * __gnat_hostent_h_addr (struct hostent * h, int index) {
 650   return h->h_addr_list[index];
 651 }
 652
 653 /*
 654  * Accessor functions for struct servent.
 655  *
 656  * These are needed because servent has different representations on different
 657  * platforms, and we don't want to deal with that on the Ada side. For example,
 658  * on Linux, we have (see /usr/include netdb.h):
 659  *
 660  *   struct servent
 661  *   {
 662  *     char *s_name;
 663  *     char **s_aliases;
 664  *     int s_port;
 665  *     char *s_proto;
 666  *   };
 667  *
 668  * and on Windows (see mingw's socket.h):
 669  *
 670  *   struct servent {
 671  *     char *s_name;
 672  *     char **s_aliases;
 673  *   #ifdef _WIN64
 674  *     char *s_proto;
 675  *     short s_port;
 676  *   #else
 677  *     short s_port;
 678  *     char *s_proto;
 679  *   #endif
 680  *   };
 681  */
 682
 683 char *
 684 __gnat_servent_s_name (struct servent * s)
 685 {
 686   return s->s_name;
 687 }
 688
 689 char *
 690 __gnat_servent_s_alias (struct servent * s, int index)
 691 {
 692   return s->s_aliases[index];
 693 }
 694
 695 unsigned short
 696 __gnat_servent_s_port (struct servent * s)
 697 {
 698   return s->s_port;
 699 }
 700
 701 char *
 702 __gnat_servent_s_proto (struct servent * s)
 703 {
 704   return s->s_proto;
 705 }
 706
 707 #if defined(AF_INET6) && !defined(__rtems__)
 708
 709 int __gnat_getaddrinfo(
 710   const char *node,
 711   const char *service,
 712   const struct addrinfo *hints,
 713   struct addrinfo **res)
 714 {
 715   return getaddrinfo(node, service, hints, res);
 716 }
 717
 718 int __gnat_getnameinfo(
 719   const struct sockaddr *sa, socklen_t salen,
 720   char *host, size_t hostlen,
 721   char *serv, size_t servlen, int flags)
 722 {
 723   return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
 724 }
 725
 726 void __gnat_freeaddrinfo(struct addrinfo *res) {
 727    freeaddrinfo(res);
 728 }
 729
 730 const char * __gnat_gai_strerror(int errcode) {
 731 #if defined(_WIN32) ||  defined(__vxworks)
 732   // gai_strerror thread usafe on Windows and is not available on some vxWorks
 733   // versions
 734
 735   switch (errcode) {
 736     case EAI_AGAIN:
 737       return "Temporary failure in name resolution.";
 738     case EAI_BADFLAGS:
 739       return "Invalid value for ai_flags.";
 740     case EAI_FAIL:
 741       return "Nonrecoverable failure in name resolution.";
 742     case EAI_FAMILY:
 743       return "The ai_family member is not supported.";
 744     case EAI_MEMORY:
 745       return "Memory allocation failure.";
 746 #ifdef EAI_NODATA
 747     // Could be not defined under the vxWorks
 748     case EAI_NODATA:
 749       return "No address associated with nodename.";
 750 #endif
 751 #if EAI_NODATA != EAI_NONAME
 752     /* with mingw64 runtime EAI_NODATA and EAI_NONAME have the same value.
 753        This applies to both win32 and win64 */
 754     case EAI_NONAME:
 755       return "Neither nodename nor servname provided, or not known.";
 756 #endif
 757     case EAI_SERVICE:
 758       return "The servname parameter is not supported for ai_socktype.";
 759     case EAI_SOCKTYPE:
 760       return "The ai_socktype member is not supported.";
 761 #ifdef EAI_SYSTEM
 762     // Could be not defined, at least on Windows
 763     case EAI_SYSTEM:
 764       return "System error returned in errno";
 765 #endif
 766     default:
 767       return "Unknown error.";
 768     }
 769 #else
 770    return gai_strerror(errcode);
 771 #endif
 772 }
 773
 774 #else
 775
 776 int __gnat_getaddrinfo(
 777   const char *node,
 778   const char *service,
 779   const struct addrinfo *hints,
 780   struct addrinfo **res)
 781 {
 782   return -1;
 783 }
 784
 785 int __gnat_getnameinfo(
 786   const struct sockaddr *sa, socklen_t salen,
 787   char *host, size_t hostlen,
 788   char *serv, size_t servlen, int flags)
 789 {
 790   return -1;
 791 }
 792
 793 void __gnat_freeaddrinfo(struct addrinfo *res) {
 794 }
 795
 796 const char * __gnat_gai_strerror(int errcode) {
 797    return "getaddinfo functions family is not supported";
 798 }
 799
 800 #endif
 801
 802 int __gnat_minus_500ms() {
 803 #if defined (_WIN32)
 804   // Windows Server 2019 and Windows 8.0 do not need 500 millisecond socket
 805   // timeout correction.
 806   if (IsWindowsServer()) {
 807     OSVERSIONINFO osvi;
 808     ZeroMemory(&osvi, sizeof(OSVERSIONINFO));
 809     osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
 810     // Documentation proposes to use IsWindowsVersionOrGreater(10, 0, 17763)
 811     // but it does not compare by the build number (last parameter).
 812     GetVersionEx(&osvi);
 813     return osvi.dwMajorVersion < 10
 814         || (osvi.dwMajorVersion == 10
 815             && osvi.dwMinorVersion == 0
 816             && osvi.dwBuildNumber < 17763);
 817   } else {
 818     return !IsWindows8OrGreater();
 819   }
 820 #else
 821   return 0;
 822 #endif
 823 }
 824
 825 #endif /* defined(HAVE_SOCKETS) */