1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel (at) haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at https://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 ***************************************************************************/ 22 23 #include "curl_setup.h" 24 25 #ifdef HAVE_NETINET_IN_H 26 #include <netinet/in.h> 27 #endif 28 #ifdef HAVE_NETDB_H 29 #include <netdb.h> 30 #endif 31 #ifdef HAVE_ARPA_INET_H 32 #include <arpa/inet.h> 33 #endif 34 #ifdef __VMS 35 #include <in.h> 36 #include <inet.h> 37 #endif 38 39 #ifdef HAVE_SETJMP_H 40 #include <setjmp.h> 41 #endif 42 #ifdef HAVE_SIGNAL_H 43 #include <signal.h> 44 #endif 45 46 #ifdef HAVE_PROCESS_H 47 #include <process.h> 48 #endif 49 50 #include "urldata.h" 51 #include "sendf.h" 52 #include "hostip.h" 53 #include "hash.h" 54 #include "share.h" 55 #include "strerror.h" 56 #include "url.h" 57 #include "inet_ntop.h" 58 #include "warnless.h" 59 /* The last 3 #include files should be in this order */ 60 #include "curl_printf.h" 61 #include "curl_memory.h" 62 #include "memdebug.h" 63 64 #if defined(CURLRES_SYNCH) && \ 65 defined(HAVE_ALARM) && defined(SIGALRM) && defined(HAVE_SIGSETJMP) 66 /* alarm-based timeouts can only be used with all the dependencies satisfied */ 67 #define USE_ALARM_TIMEOUT 68 #endif 69 70 /* 71 * hostip.c explained 72 * ================== 73 * 74 * The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c 75 * source file are these: 76 * 77 * CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use 78 * that. The host may not be able to resolve IPv6, but we don't really have to 79 * take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4 80 * defined. 81 * 82 * CURLRES_ARES - is defined if libcurl is built to use c-ares for 83 * asynchronous name resolves. This can be Windows or *nix. 84 * 85 * CURLRES_THREADED - is defined if libcurl is built to run under (native) 86 * Windows, and then the name resolve will be done in a new thread, and the 87 * supported API will be the same as for ares-builds. 88 * 89 * If any of the two previous are defined, CURLRES_ASYNCH is defined too. If 90 * libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is 91 * defined. 92 * 93 * The host*.c sources files are split up like this: 94 * 95 * hostip.c - method-independent resolver functions and utility functions 96 * hostasyn.c - functions for asynchronous name resolves 97 * hostsyn.c - functions for synchronous name resolves 98 * hostip4.c - IPv4 specific functions 99 * hostip6.c - IPv6 specific functions 100 * 101 * The two asynchronous name resolver backends are implemented in: 102 * asyn-ares.c - functions for ares-using name resolves 103 * asyn-thread.c - functions for threaded name resolves 104 105 * The hostip.h is the united header file for all this. It defines the 106 * CURLRES_* defines based on the config*.h and curl_setup.h defines. 107 */ 108 109 /* These two symbols are for the global DNS cache */ 110 static struct curl_hash hostname_cache; 111 static int host_cache_initialized; 112 113 static void freednsentry(void *freethis); 114 115 /* 116 * Curl_global_host_cache_init() initializes and sets up a global DNS cache. 117 * Global DNS cache is general badness. Do not use. This will be removed in 118 * a future version. Use the share interface instead! 119 * 120 * Returns a struct curl_hash pointer on success, NULL on failure. 121 */ 122 struct curl_hash *Curl_global_host_cache_init(void) 123 { 124 int rc = 0; 125 if(!host_cache_initialized) { 126 rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str, 127 Curl_str_key_compare, freednsentry); 128 if(!rc) 129 host_cache_initialized = 1; 130 } 131 return rc?NULL:&hostname_cache; 132 } 133 134 /* 135 * Destroy and cleanup the global DNS cache 136 */ 137 void Curl_global_host_cache_dtor(void) 138 { 139 if(host_cache_initialized) { 140 Curl_hash_destroy(&hostname_cache); 141 host_cache_initialized = 0; 142 } 143 } 144 145 /* 146 * Return # of adresses in a Curl_addrinfo struct 147 */ 148 int Curl_num_addresses(const Curl_addrinfo *addr) 149 { 150 int i = 0; 151 while(addr) { 152 addr = addr->ai_next; 153 i++; 154 } 155 return i; 156 } 157 158 /* 159 * Curl_printable_address() returns a printable version of the 1st address 160 * given in the 'ai' argument. The result will be stored in the buf that is 161 * bufsize bytes big. 162 * 163 * If the conversion fails, it returns NULL. 164 */ 165 const char * 166 Curl_printable_address(const Curl_addrinfo *ai, char *buf, size_t bufsize) 167 { 168 const struct sockaddr_in *sa4; 169 const struct in_addr *ipaddr4; 170 #ifdef ENABLE_IPV6 171 const struct sockaddr_in6 *sa6; 172 const struct in6_addr *ipaddr6; 173 #endif 174 175 switch (ai->ai_family) { 176 case AF_INET: 177 sa4 = (const void *)ai->ai_addr; 178 ipaddr4 = &sa4->sin_addr; 179 return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr4, buf, 180 bufsize); 181 #ifdef ENABLE_IPV6 182 case AF_INET6: 183 sa6 = (const void *)ai->ai_addr; 184 ipaddr6 = &sa6->sin6_addr; 185 return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr6, buf, 186 bufsize); 187 #endif 188 default: 189 break; 190 } 191 return NULL; 192 } 193 194 /* 195 * Return a hostcache id string for the provided host + port, to be used by 196 * the DNS caching. 197 */ 198 static char * 199 create_hostcache_id(const char *name, int port) 200 { 201 /* create and return the new allocated entry */ 202 char *id = aprintf("%s:%d", name, port); 203 char *ptr = id; 204 if(ptr) { 205 /* lower case the name part */ 206 while(*ptr && (*ptr != ':')) { 207 *ptr = (char)TOLOWER(*ptr); 208 ptr++; 209 } 210 } 211 return id; 212 } 213 214 struct hostcache_prune_data { 215 long cache_timeout; 216 time_t now; 217 }; 218 219 /* 220 * This function is set as a callback to be called for every entry in the DNS 221 * cache when we want to prune old unused entries. 222 * 223 * Returning non-zero means remove the entry, return 0 to keep it in the 224 * cache. 225 */ 226 static int 227 hostcache_timestamp_remove(void *datap, void *hc) 228 { 229 struct hostcache_prune_data *data = 230 (struct hostcache_prune_data *) datap; 231 struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc; 232 233 return (0 != c->timestamp) 234 && (data->now - c->timestamp >= data->cache_timeout); 235 } 236 237 /* 238 * Prune the DNS cache. This assumes that a lock has already been taken. 239 */ 240 static void 241 hostcache_prune(struct curl_hash *hostcache, long cache_timeout, time_t now) 242 { 243 struct hostcache_prune_data user; 244 245 user.cache_timeout = cache_timeout; 246 user.now = now; 247 248 Curl_hash_clean_with_criterium(hostcache, 249 (void *) &user, 250 hostcache_timestamp_remove); 251 } 252 253 /* 254 * Library-wide function for pruning the DNS cache. This function takes and 255 * returns the appropriate locks. 256 */ 257 void Curl_hostcache_prune(struct Curl_easy *data) 258 { 259 time_t now; 260 261 if((data->set.dns_cache_timeout == -1) || !data->dns.hostcache) 262 /* cache forever means never prune, and NULL hostcache means 263 we can't do it */ 264 return; 265 266 if(data->share) 267 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 268 269 time(&now); 270 271 /* Remove outdated and unused entries from the hostcache */ 272 hostcache_prune(data->dns.hostcache, 273 data->set.dns_cache_timeout, 274 now); 275 276 if(data->share) 277 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 278 } 279 280 #ifdef HAVE_SIGSETJMP 281 /* Beware this is a global and unique instance. This is used to store the 282 return address that we can jump back to from inside a signal handler. This 283 is not thread-safe stuff. */ 284 sigjmp_buf curl_jmpenv; 285 #endif 286 287 /* lookup address, returns entry if found and not stale */ 288 static struct Curl_dns_entry * 289 fetch_addr(struct connectdata *conn, 290 const char *hostname, 291 int port) 292 { 293 char *entry_id = NULL; 294 struct Curl_dns_entry *dns = NULL; 295 size_t entry_len; 296 struct Curl_easy *data = conn->data; 297 298 /* Create an entry id, based upon the hostname and port */ 299 entry_id = create_hostcache_id(hostname, port); 300 /* If we can't create the entry id, fail */ 301 if(!entry_id) 302 return dns; 303 304 entry_len = strlen(entry_id); 305 306 /* See if its already in our dns cache */ 307 dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1); 308 309 if(dns && (data->set.dns_cache_timeout != -1)) { 310 /* See whether the returned entry is stale. Done before we release lock */ 311 struct hostcache_prune_data user; 312 313 time(&user.now); 314 user.cache_timeout = data->set.dns_cache_timeout; 315 316 if(hostcache_timestamp_remove(&user, dns)) { 317 infof(data, "Hostname in DNS cache was stale, zapped\n"); 318 dns = NULL; /* the memory deallocation is being handled by the hash */ 319 Curl_hash_delete(data->dns.hostcache, entry_id, entry_len+1); 320 } 321 } 322 323 /* free the allocated entry_id again */ 324 free(entry_id); 325 326 return dns; 327 } 328 329 /* 330 * Curl_fetch_addr() fetches a 'Curl_dns_entry' already in the DNS cache. 331 * 332 * Curl_resolv() checks initially and multi_runsingle() checks each time 333 * it discovers the handle in the state WAITRESOLVE whether the hostname 334 * has already been resolved and the address has already been stored in 335 * the DNS cache. This short circuits waiting for a lot of pending 336 * lookups for the same hostname requested by different handles. 337 * 338 * Returns the Curl_dns_entry entry pointer or NULL if not in the cache. 339 * 340 * The returned data *MUST* be "unlocked" with Curl_resolv_unlock() after 341 * use, or we'll leak memory! 342 */ 343 struct Curl_dns_entry * 344 Curl_fetch_addr(struct connectdata *conn, 345 const char *hostname, 346 int port) 347 { 348 struct Curl_easy *data = conn->data; 349 struct Curl_dns_entry *dns = NULL; 350 351 if(data->share) 352 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 353 354 dns = fetch_addr(conn, hostname, port); 355 356 if(dns) 357 dns->inuse++; /* we use it! */ 358 359 if(data->share) 360 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 361 362 return dns; 363 } 364 365 /* 366 * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache. 367 * 368 * When calling Curl_resolv() has resulted in a response with a returned 369 * address, we call this function to store the information in the dns 370 * cache etc 371 * 372 * Returns the Curl_dns_entry entry pointer or NULL if the storage failed. 373 */ 374 struct Curl_dns_entry * 375 Curl_cache_addr(struct Curl_easy *data, 376 Curl_addrinfo *addr, 377 const char *hostname, 378 int port) 379 { 380 char *entry_id; 381 size_t entry_len; 382 struct Curl_dns_entry *dns; 383 struct Curl_dns_entry *dns2; 384 385 /* Create an entry id, based upon the hostname and port */ 386 entry_id = create_hostcache_id(hostname, port); 387 /* If we can't create the entry id, fail */ 388 if(!entry_id) 389 return NULL; 390 entry_len = strlen(entry_id); 391 392 /* Create a new cache entry */ 393 dns = calloc(1, sizeof(struct Curl_dns_entry)); 394 if(!dns) { 395 free(entry_id); 396 return NULL; 397 } 398 399 dns->inuse = 1; /* the cache has the first reference */ 400 dns->addr = addr; /* this is the address(es) */ 401 time(&dns->timestamp); 402 if(dns->timestamp == 0) 403 dns->timestamp = 1; /* zero indicates CURLOPT_RESOLVE entry */ 404 405 /* Store the resolved data in our DNS cache. */ 406 dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len+1, 407 (void *)dns); 408 if(!dns2) { 409 free(dns); 410 free(entry_id); 411 return NULL; 412 } 413 414 dns = dns2; 415 dns->inuse++; /* mark entry as in-use */ 416 417 /* free the allocated entry_id */ 418 free(entry_id); 419 420 return dns; 421 } 422 423 /* 424 * Curl_resolv() is the main name resolve function within libcurl. It resolves 425 * a name and returns a pointer to the entry in the 'entry' argument (if one 426 * is provided). This function might return immediately if we're using asynch 427 * resolves. See the return codes. 428 * 429 * The cache entry we return will get its 'inuse' counter increased when this 430 * function is used. You MUST call Curl_resolv_unlock() later (when you're 431 * done using this struct) to decrease the counter again. 432 * 433 * In debug mode, we specifically test for an interface name "LocalHost" 434 * and resolve "localhost" instead as a means to permit test cases 435 * to connect to a local test server with any host name. 436 * 437 * Return codes: 438 * 439 * CURLRESOLV_ERROR (-1) = error, no pointer 440 * CURLRESOLV_RESOLVED (0) = OK, pointer provided 441 * CURLRESOLV_PENDING (1) = waiting for response, no pointer 442 */ 443 444 int Curl_resolv(struct connectdata *conn, 445 const char *hostname, 446 int port, 447 struct Curl_dns_entry **entry) 448 { 449 struct Curl_dns_entry *dns = NULL; 450 struct Curl_easy *data = conn->data; 451 CURLcode result; 452 int rc = CURLRESOLV_ERROR; /* default to failure */ 453 454 *entry = NULL; 455 456 if(data->share) 457 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 458 459 dns = fetch_addr(conn, hostname, port); 460 461 if(dns) { 462 infof(data, "Hostname %s was found in DNS cache\n", hostname); 463 dns->inuse++; /* we use it! */ 464 rc = CURLRESOLV_RESOLVED; 465 } 466 467 if(data->share) 468 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 469 470 if(!dns) { 471 /* The entry was not in the cache. Resolve it to IP address */ 472 473 Curl_addrinfo *addr; 474 int respwait; 475 476 /* Check what IP specifics the app has requested and if we can provide it. 477 * If not, bail out. */ 478 if(!Curl_ipvalid(conn)) 479 return CURLRESOLV_ERROR; 480 481 /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a 482 non-zero value indicating that we need to wait for the response to the 483 resolve call */ 484 addr = Curl_getaddrinfo(conn, 485 #ifdef DEBUGBUILD 486 (data->set.str[STRING_DEVICE] 487 && !strcmp(data->set.str[STRING_DEVICE], 488 "LocalHost"))?"localhost": 489 #endif 490 hostname, port, &respwait); 491 492 if(!addr) { 493 if(respwait) { 494 /* the response to our resolve call will come asynchronously at 495 a later time, good or bad */ 496 /* First, check that we haven't received the info by now */ 497 result = Curl_resolver_is_resolved(conn, &dns); 498 if(result) /* error detected */ 499 return CURLRESOLV_ERROR; 500 if(dns) 501 rc = CURLRESOLV_RESOLVED; /* pointer provided */ 502 else 503 rc = CURLRESOLV_PENDING; /* no info yet */ 504 } 505 } 506 else { 507 if(data->share) 508 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 509 510 /* we got a response, store it in the cache */ 511 dns = Curl_cache_addr(data, addr, hostname, port); 512 513 if(data->share) 514 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 515 516 if(!dns) 517 /* returned failure, bail out nicely */ 518 Curl_freeaddrinfo(addr); 519 else 520 rc = CURLRESOLV_RESOLVED; 521 } 522 } 523 524 *entry = dns; 525 526 return rc; 527 } 528 529 #ifdef USE_ALARM_TIMEOUT 530 /* 531 * This signal handler jumps back into the main libcurl code and continues 532 * execution. This effectively causes the remainder of the application to run 533 * within a signal handler which is nonportable and could lead to problems. 534 */ 535 static 536 RETSIGTYPE alarmfunc(int sig) 537 { 538 /* this is for "-ansi -Wall -pedantic" to stop complaining! (rabe) */ 539 (void)sig; 540 siglongjmp(curl_jmpenv, 1); 541 return; 542 } 543 #endif /* USE_ALARM_TIMEOUT */ 544 545 /* 546 * Curl_resolv_timeout() is the same as Curl_resolv() but specifies a 547 * timeout. This function might return immediately if we're using asynch 548 * resolves. See the return codes. 549 * 550 * The cache entry we return will get its 'inuse' counter increased when this 551 * function is used. You MUST call Curl_resolv_unlock() later (when you're 552 * done using this struct) to decrease the counter again. 553 * 554 * If built with a synchronous resolver and use of signals is not 555 * disabled by the application, then a nonzero timeout will cause a 556 * timeout after the specified number of milliseconds. Otherwise, timeout 557 * is ignored. 558 * 559 * Return codes: 560 * 561 * CURLRESOLV_TIMEDOUT(-2) = warning, time too short or previous alarm expired 562 * CURLRESOLV_ERROR (-1) = error, no pointer 563 * CURLRESOLV_RESOLVED (0) = OK, pointer provided 564 * CURLRESOLV_PENDING (1) = waiting for response, no pointer 565 */ 566 567 int Curl_resolv_timeout(struct connectdata *conn, 568 const char *hostname, 569 int port, 570 struct Curl_dns_entry **entry, 571 time_t timeoutms) 572 { 573 #ifdef USE_ALARM_TIMEOUT 574 #ifdef HAVE_SIGACTION 575 struct sigaction keep_sigact; /* store the old struct here */ 576 volatile bool keep_copysig = FALSE; /* wether old sigact has been saved */ 577 struct sigaction sigact; 578 #else 579 #ifdef HAVE_SIGNAL 580 void (*keep_sigact)(int); /* store the old handler here */ 581 #endif /* HAVE_SIGNAL */ 582 #endif /* HAVE_SIGACTION */ 583 volatile long timeout; 584 volatile unsigned int prev_alarm = 0; 585 struct Curl_easy *data = conn->data; 586 #endif /* USE_ALARM_TIMEOUT */ 587 int rc; 588 589 *entry = NULL; 590 591 if(timeoutms < 0) 592 /* got an already expired timeout */ 593 return CURLRESOLV_TIMEDOUT; 594 595 #ifdef USE_ALARM_TIMEOUT 596 if(data->set.no_signal) 597 /* Ignore the timeout when signals are disabled */ 598 timeout = 0; 599 else 600 timeout = timeoutms; 601 602 if(!timeout) 603 /* USE_ALARM_TIMEOUT defined, but no timeout actually requested */ 604 return Curl_resolv(conn, hostname, port, entry); 605 606 if(timeout < 1000) { 607 /* The alarm() function only provides integer second resolution, so if 608 we want to wait less than one second we must bail out already now. */ 609 failf(data, 610 "remaining timeout of %ld too small to resolve via SIGALRM method", 611 timeout); 612 return CURLRESOLV_TIMEDOUT; 613 } 614 /* This allows us to time-out from the name resolver, as the timeout 615 will generate a signal and we will siglongjmp() from that here. 616 This technique has problems (see alarmfunc). 617 This should be the last thing we do before calling Curl_resolv(), 618 as otherwise we'd have to worry about variables that get modified 619 before we invoke Curl_resolv() (and thus use "volatile"). */ 620 if(sigsetjmp(curl_jmpenv, 1)) { 621 /* this is coming from a siglongjmp() after an alarm signal */ 622 failf(data, "name lookup timed out"); 623 rc = CURLRESOLV_ERROR; 624 goto clean_up; 625 } 626 else { 627 /************************************************************* 628 * Set signal handler to catch SIGALRM 629 * Store the old value to be able to set it back later! 630 *************************************************************/ 631 #ifdef HAVE_SIGACTION 632 sigaction(SIGALRM, NULL, &sigact); 633 keep_sigact = sigact; 634 keep_copysig = TRUE; /* yes, we have a copy */ 635 sigact.sa_handler = alarmfunc; 636 #ifdef SA_RESTART 637 /* HPUX doesn't have SA_RESTART but defaults to that behaviour! */ 638 sigact.sa_flags &= ~SA_RESTART; 639 #endif 640 /* now set the new struct */ 641 sigaction(SIGALRM, &sigact, NULL); 642 #else /* HAVE_SIGACTION */ 643 /* no sigaction(), revert to the much lamer signal() */ 644 #ifdef HAVE_SIGNAL 645 keep_sigact = signal(SIGALRM, alarmfunc); 646 #endif 647 #endif /* HAVE_SIGACTION */ 648 649 /* alarm() makes a signal get sent when the timeout fires off, and that 650 will abort system calls */ 651 prev_alarm = alarm(curlx_sltoui(timeout/1000L)); 652 } 653 654 #else 655 #ifndef CURLRES_ASYNCH 656 if(timeoutms) 657 infof(conn->data, "timeout on name lookup is not supported\n"); 658 #else 659 (void)timeoutms; /* timeoutms not used with an async resolver */ 660 #endif 661 #endif /* USE_ALARM_TIMEOUT */ 662 663 /* Perform the actual name resolution. This might be interrupted by an 664 * alarm if it takes too long. 665 */ 666 rc = Curl_resolv(conn, hostname, port, entry); 667 668 #ifdef USE_ALARM_TIMEOUT 669 clean_up: 670 671 if(!prev_alarm) 672 /* deactivate a possibly active alarm before uninstalling the handler */ 673 alarm(0); 674 675 #ifdef HAVE_SIGACTION 676 if(keep_copysig) { 677 /* we got a struct as it looked before, now put that one back nice 678 and clean */ 679 sigaction(SIGALRM, &keep_sigact, NULL); /* put it back */ 680 } 681 #else 682 #ifdef HAVE_SIGNAL 683 /* restore the previous SIGALRM handler */ 684 signal(SIGALRM, keep_sigact); 685 #endif 686 #endif /* HAVE_SIGACTION */ 687 688 /* switch back the alarm() to either zero or to what it was before minus 689 the time we spent until now! */ 690 if(prev_alarm) { 691 /* there was an alarm() set before us, now put it back */ 692 unsigned long elapsed_ms = Curl_tvdiff(Curl_tvnow(), conn->created); 693 694 /* the alarm period is counted in even number of seconds */ 695 unsigned long alarm_set = prev_alarm - elapsed_ms/1000; 696 697 if(!alarm_set || 698 ((alarm_set >= 0x80000000) && (prev_alarm < 0x80000000)) ) { 699 /* if the alarm time-left reached zero or turned "negative" (counted 700 with unsigned values), we should fire off a SIGALRM here, but we 701 won't, and zero would be to switch it off so we never set it to 702 less than 1! */ 703 alarm(1); 704 rc = CURLRESOLV_TIMEDOUT; 705 failf(data, "Previous alarm fired off!"); 706 } 707 else 708 alarm((unsigned int)alarm_set); 709 } 710 #endif /* USE_ALARM_TIMEOUT */ 711 712 return rc; 713 } 714 715 /* 716 * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been 717 * made, the struct may be destroyed due to pruning. It is important that only 718 * one unlock is made for each Curl_resolv() call. 719 * 720 * May be called with 'data' == NULL for global cache. 721 */ 722 void Curl_resolv_unlock(struct Curl_easy *data, struct Curl_dns_entry *dns) 723 { 724 if(data && data->share) 725 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 726 727 freednsentry(dns); 728 729 if(data && data->share) 730 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 731 } 732 733 /* 734 * File-internal: release cache dns entry reference, free if inuse drops to 0 735 */ 736 static void freednsentry(void *freethis) 737 { 738 struct Curl_dns_entry *dns = (struct Curl_dns_entry *) freethis; 739 DEBUGASSERT(dns && (dns->inuse>0)); 740 741 dns->inuse--; 742 if(dns->inuse == 0) { 743 Curl_freeaddrinfo(dns->addr); 744 free(dns); 745 } 746 } 747 748 /* 749 * Curl_mk_dnscache() inits a new DNS cache and returns success/failure. 750 */ 751 int Curl_mk_dnscache(struct curl_hash *hash) 752 { 753 return Curl_hash_init(hash, 7, Curl_hash_str, Curl_str_key_compare, 754 freednsentry); 755 } 756 757 /* 758 * Curl_hostcache_clean() 759 * 760 * This _can_ be called with 'data' == NULL but then of course no locking 761 * can be done! 762 */ 763 764 void Curl_hostcache_clean(struct Curl_easy *data, 765 struct curl_hash *hash) 766 { 767 if(data && data->share) 768 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 769 770 Curl_hash_clean(hash); 771 772 if(data && data->share) 773 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 774 } 775 776 777 CURLcode Curl_loadhostpairs(struct Curl_easy *data) 778 { 779 struct curl_slist *hostp; 780 char hostname[256]; 781 char address[256]; 782 int port; 783 784 for(hostp = data->change.resolve; hostp; hostp = hostp->next) { 785 if(!hostp->data) 786 continue; 787 if(hostp->data[0] == '-') { 788 char *entry_id; 789 size_t entry_len; 790 791 if(2 != sscanf(hostp->data + 1, "%255[^:]:%d", hostname, &port)) { 792 infof(data, "Couldn't parse CURLOPT_RESOLVE removal entry '%s'!\n", 793 hostp->data); 794 continue; 795 } 796 797 /* Create an entry id, based upon the hostname and port */ 798 entry_id = create_hostcache_id(hostname, port); 799 /* If we can't create the entry id, fail */ 800 if(!entry_id) { 801 return CURLE_OUT_OF_MEMORY; 802 } 803 804 entry_len = strlen(entry_id); 805 806 if(data->share) 807 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 808 809 /* delete entry, ignore if it didn't exist */ 810 Curl_hash_delete(data->dns.hostcache, entry_id, entry_len+1); 811 812 if(data->share) 813 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 814 815 /* free the allocated entry_id again */ 816 free(entry_id); 817 } 818 else { 819 struct Curl_dns_entry *dns; 820 Curl_addrinfo *addr; 821 char *entry_id; 822 size_t entry_len; 823 824 if(3 != sscanf(hostp->data, "%255[^:]:%d:%255s", hostname, &port, 825 address)) { 826 infof(data, "Couldn't parse CURLOPT_RESOLVE entry '%s'!\n", 827 hostp->data); 828 continue; 829 } 830 831 addr = Curl_str2addr(address, port); 832 if(!addr) { 833 infof(data, "Address in '%s' found illegal!\n", hostp->data); 834 continue; 835 } 836 837 /* Create an entry id, based upon the hostname and port */ 838 entry_id = create_hostcache_id(hostname, port); 839 /* If we can't create the entry id, fail */ 840 if(!entry_id) { 841 Curl_freeaddrinfo(addr); 842 return CURLE_OUT_OF_MEMORY; 843 } 844 845 entry_len = strlen(entry_id); 846 847 if(data->share) 848 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 849 850 /* See if its already in our dns cache */ 851 dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1); 852 853 /* free the allocated entry_id again */ 854 free(entry_id); 855 856 if(!dns) { 857 /* if not in the cache already, put this host in the cache */ 858 dns = Curl_cache_addr(data, addr, hostname, port); 859 if(dns) { 860 dns->timestamp = 0; /* mark as added by CURLOPT_RESOLVE */ 861 /* release the returned reference; the cache itself will keep the 862 * entry alive: */ 863 dns->inuse--; 864 } 865 } 866 else 867 /* this is a duplicate, free it again */ 868 Curl_freeaddrinfo(addr); 869 870 if(data->share) 871 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 872 873 if(!dns) { 874 Curl_freeaddrinfo(addr); 875 return CURLE_OUT_OF_MEMORY; 876 } 877 infof(data, "Added %s:%d:%s to DNS cache\n", 878 hostname, port, address); 879 } 880 } 881 data->change.resolve = NULL; /* dealt with now */ 882 883 return CURLE_OK; 884 } 885