1 | /* |
2 | * Copyright (c) 1988, 1993 |
3 | * The Regents of the University of California. All rights reserved. |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
8 | * 1. Redistributions of source code must retain the above copyright |
9 | * notice, this list of conditions and the following disclaimer. |
10 | * 2. Redistributions in binary form must reproduce the above copyright |
11 | * notice, this list of conditions and the following disclaimer in the |
12 | * documentation and/or other materials provided with the distribution. |
13 | * 4. Neither the name of the University nor the names of its contributors |
14 | * may be used to endorse or promote products derived from this software |
15 | * without specific prior written permission. |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
27 | * SUCH DAMAGE. |
28 | */ |
29 | |
30 | /* |
31 | * Portions Copyright (c) 1993 by Digital Equipment Corporation. |
32 | * |
33 | * Permission to use, copy, modify, and distribute this software for any |
34 | * purpose with or without fee is hereby granted, provided that the above |
35 | * copyright notice and this permission notice appear in all copies, and that |
36 | * the name of Digital Equipment Corporation not be used in advertising or |
37 | * publicity pertaining to distribution of the document or software without |
38 | * specific, written prior permission. |
39 | * |
40 | * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL |
41 | * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES |
42 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT |
43 | * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
44 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
45 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
46 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
47 | * SOFTWARE. |
48 | */ |
49 | |
50 | /* |
51 | * Portions Copyright (c) 1996-1999 by Internet Software Consortium. |
52 | * |
53 | * Permission to use, copy, modify, and distribute this software for any |
54 | * purpose with or without fee is hereby granted, provided that the above |
55 | * copyright notice and this permission notice appear in all copies. |
56 | * |
57 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
58 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
59 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
60 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
61 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
62 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
63 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
64 | * SOFTWARE. |
65 | */ |
66 | |
67 | #include <assert.h> |
68 | #include <sys/types.h> |
69 | #include <sys/param.h> |
70 | #include <netinet/in.h> |
71 | #include <arpa/inet.h> |
72 | #include <arpa/nameser.h> |
73 | #include <ctype.h> |
74 | #include <errno.h> |
75 | #include <netdb.h> |
76 | #include <resolv.h> |
77 | #include <resolv/resolv-internal.h> |
78 | #include <resolv/resolv_context.h> |
79 | #include <stdio.h> |
80 | #include <stdlib.h> |
81 | #include <string.h> |
82 | #include <shlib-compat.h> |
83 | |
84 | #if PACKETSZ > 65536 |
85 | #define MAXPACKET PACKETSZ |
86 | #else |
87 | #define MAXPACKET 65536 |
88 | #endif |
89 | |
90 | #define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1) |
91 | |
92 | static int |
93 | __res_context_querydomain (struct resolv_context *, |
94 | const char *name, const char *domain, |
95 | int class, int type, unsigned char *answer, int anslen, |
96 | unsigned char **answerp, unsigned char **answerp2, int *nanswerp2, |
97 | int *resplen2, int *answerp2_malloced); |
98 | |
99 | /* Formulate a normal query, send, and await answer. Returned answer |
100 | is placed in supplied buffer ANSWER. Perform preliminary check of |
101 | answer, returning success only if no error is indicated and the |
102 | answer count is nonzero. Return the size of the response on |
103 | success, -1 on error. Error number is left in h_errno. |
104 | |
105 | Caller must parse answer and determine whether it answers the |
106 | question. */ |
107 | int |
108 | __res_context_query (struct resolv_context *ctx, const char *name, |
109 | int class, int type, |
110 | unsigned char *answer, int anslen, |
111 | unsigned char **answerp, unsigned char **answerp2, |
112 | int *nanswerp2, int *resplen2, int *answerp2_malloced) |
113 | { |
114 | struct __res_state *statp = ctx->resp; |
115 | HEADER *hp = (HEADER *) answer; |
116 | HEADER *hp2; |
117 | int n, use_malloc = 0; |
118 | |
119 | size_t bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * QUERYSIZE; |
120 | u_char *buf = alloca (bufsize); |
121 | u_char *query1 = buf; |
122 | int nquery1 = -1; |
123 | u_char *query2 = NULL; |
124 | int nquery2 = 0; |
125 | |
126 | again: |
127 | hp->rcode = NOERROR; /* default */ |
128 | |
129 | if (type == T_QUERY_A_AND_AAAA) |
130 | { |
131 | n = __res_context_mkquery (ctx, QUERY, name, class, T_A, NULL, |
132 | query1, bufsize); |
133 | if (n > 0) |
134 | { |
135 | if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) |
136 | { |
137 | /* Use RESOLV_EDNS_BUFFER_SIZE because the receive |
138 | buffer can be reallocated. */ |
139 | n = __res_nopt (ctx, n, query1, bufsize, |
140 | RESOLV_EDNS_BUFFER_SIZE); |
141 | if (n < 0) |
142 | goto unspec_nomem; |
143 | } |
144 | |
145 | nquery1 = n; |
146 | /* Align the buffer. */ |
147 | int npad = ((nquery1 + __alignof__ (HEADER) - 1) |
148 | & ~(__alignof__ (HEADER) - 1)) - nquery1; |
149 | if (n > bufsize - npad) |
150 | { |
151 | n = -1; |
152 | goto unspec_nomem; |
153 | } |
154 | int nused = n + npad; |
155 | query2 = buf + nused; |
156 | n = __res_context_mkquery (ctx, QUERY, name, class, T_AAAA, |
157 | NULL, query2, bufsize - nused); |
158 | if (n > 0 |
159 | && (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) |
160 | /* Use RESOLV_EDNS_BUFFER_SIZE because the receive |
161 | buffer can be reallocated. */ |
162 | n = __res_nopt (ctx, n, query2, bufsize, |
163 | RESOLV_EDNS_BUFFER_SIZE); |
164 | nquery2 = n; |
165 | } |
166 | |
167 | unspec_nomem:; |
168 | } |
169 | else |
170 | { |
171 | n = __res_context_mkquery (ctx, QUERY, name, class, type, NULL, |
172 | query1, bufsize); |
173 | |
174 | if (n > 0 |
175 | && (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) |
176 | { |
177 | /* Use RESOLV_EDNS_BUFFER_SIZE if the receive buffer |
178 | can be reallocated. */ |
179 | size_t advertise; |
180 | if (answerp == NULL) |
181 | advertise = anslen; |
182 | else |
183 | advertise = RESOLV_EDNS_BUFFER_SIZE; |
184 | n = __res_nopt (ctx, n, query1, bufsize, advertise); |
185 | } |
186 | |
187 | nquery1 = n; |
188 | } |
189 | |
190 | if (__glibc_unlikely (n <= 0) && !use_malloc) { |
191 | /* Retry just in case res_nmkquery failed because of too |
192 | short buffer. Shouldn't happen. */ |
193 | bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * MAXPACKET; |
194 | buf = malloc (bufsize); |
195 | if (buf != NULL) { |
196 | query1 = buf; |
197 | use_malloc = 1; |
198 | goto again; |
199 | } |
200 | } |
201 | if (__glibc_unlikely (n <= 0)) { |
202 | RES_SET_H_ERRNO(statp, NO_RECOVERY); |
203 | if (use_malloc) |
204 | free (buf); |
205 | return (n); |
206 | } |
207 | assert (answerp == NULL || (void *) *answerp == (void *) answer); |
208 | n = __res_context_send (ctx, query1, nquery1, query2, nquery2, answer, |
209 | anslen, answerp, answerp2, nanswerp2, resplen2, |
210 | answerp2_malloced); |
211 | if (use_malloc) |
212 | free (buf); |
213 | if (n < 0) { |
214 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
215 | return (n); |
216 | } |
217 | |
218 | if (answerp != NULL) |
219 | /* __res_context_send might have reallocated the buffer. */ |
220 | hp = (HEADER *) *answerp; |
221 | |
222 | /* We simplify the following tests by assigning HP to HP2 or |
223 | vice versa. It is easy to verify that this is the same as |
224 | ignoring all tests of HP or HP2. */ |
225 | if (answerp2 == NULL || *resplen2 < (int) sizeof (HEADER)) |
226 | { |
227 | hp2 = hp; |
228 | } |
229 | else |
230 | { |
231 | hp2 = (HEADER *) *answerp2; |
232 | if (n < (int) sizeof (HEADER)) |
233 | { |
234 | hp = hp2; |
235 | } |
236 | } |
237 | |
238 | /* Make sure both hp and hp2 are defined */ |
239 | assert((hp != NULL) && (hp2 != NULL)); |
240 | |
241 | if ((hp->rcode != NOERROR || ntohs(hp->ancount) == 0) |
242 | && (hp2->rcode != NOERROR || ntohs(hp2->ancount) == 0)) { |
243 | switch (hp->rcode == NOERROR ? hp2->rcode : hp->rcode) { |
244 | case NXDOMAIN: |
245 | if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0) |
246 | || (hp2->rcode == NOERROR |
247 | && ntohs (hp2->ancount) != 0)) |
248 | goto success; |
249 | RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); |
250 | break; |
251 | case SERVFAIL: |
252 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
253 | break; |
254 | case NOERROR: |
255 | if (ntohs (hp->ancount) != 0 |
256 | || ntohs (hp2->ancount) != 0) |
257 | goto success; |
258 | RES_SET_H_ERRNO(statp, NO_DATA); |
259 | break; |
260 | case FORMERR: |
261 | case NOTIMP: |
262 | /* Servers must not reply to AAAA queries with |
263 | NOTIMP etc but some of them do. */ |
264 | if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0) |
265 | || (hp2->rcode == NOERROR |
266 | && ntohs (hp2->ancount) != 0)) |
267 | goto success; |
268 | /* FALLTHROUGH */ |
269 | case REFUSED: |
270 | default: |
271 | RES_SET_H_ERRNO(statp, NO_RECOVERY); |
272 | break; |
273 | } |
274 | return (-1); |
275 | } |
276 | success: |
277 | return (n); |
278 | } |
279 | libresolv_hidden_def (__res_context_query) |
280 | |
281 | /* Common part of res_nquery and res_query. */ |
282 | static int |
283 | context_query_common (struct resolv_context *ctx, |
284 | const char *name, int class, int type, |
285 | unsigned char *answer, int anslen) |
286 | { |
287 | if (ctx == NULL) |
288 | { |
289 | RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
290 | return -1; |
291 | } |
292 | int result = __res_context_query (ctx, name, class, type, answer, anslen, |
293 | NULL, NULL, NULL, NULL, NULL); |
294 | __resolv_context_put (ctx); |
295 | return result; |
296 | } |
297 | |
298 | int |
299 | res_nquery(res_state statp, |
300 | const char *name, /* domain name */ |
301 | int class, int type, /* class and type of query */ |
302 | u_char *answer, /* buffer to put answer */ |
303 | int anslen) /* size of answer buffer */ |
304 | { |
305 | return context_query_common |
306 | (__resolv_context_get_override (statp), name, class, type, answer, anslen); |
307 | } |
308 | |
309 | int |
310 | res_query (const char *name, int class, int type, |
311 | unsigned char *answer, int anslen) |
312 | { |
313 | return context_query_common |
314 | (__resolv_context_get (), name, class, type, answer, anslen); |
315 | } |
316 | |
317 | /* Formulate a normal query, send, and retrieve answer in supplied |
318 | buffer. Return the size of the response on success, -1 on error. |
319 | If enabled, implement search rules until answer or unrecoverable |
320 | failure is detected. Error code, if any, is left in h_errno. */ |
321 | int |
322 | __res_context_search (struct resolv_context *ctx, |
323 | const char *name, int class, int type, |
324 | unsigned char *answer, int anslen, |
325 | unsigned char **answerp, unsigned char **answerp2, |
326 | int *nanswerp2, int *resplen2, int *answerp2_malloced) |
327 | { |
328 | struct __res_state *statp = ctx->resp; |
329 | const char *cp; |
330 | HEADER *hp = (HEADER *) answer; |
331 | char tmp[NS_MAXDNAME]; |
332 | u_int dots; |
333 | int trailing_dot, ret, saved_herrno; |
334 | int got_nodata = 0, got_servfail = 0, root_on_list = 0; |
335 | int tried_as_is = 0; |
336 | int searched = 0; |
337 | |
338 | __set_errno (0); |
339 | RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */ |
340 | |
341 | dots = 0; |
342 | for (cp = name; *cp != '\0'; cp++) |
343 | dots += (*cp == '.'); |
344 | trailing_dot = 0; |
345 | if (cp > name && *--cp == '.') |
346 | trailing_dot++; |
347 | |
348 | /* If there aren't any dots, it could be a user-level alias. */ |
349 | if (!dots && (cp = __res_context_hostalias |
350 | (ctx, name, tmp, sizeof tmp))!= NULL) |
351 | return __res_context_query (ctx, cp, class, type, answer, |
352 | anslen, answerp, answerp2, |
353 | nanswerp2, resplen2, answerp2_malloced); |
354 | |
355 | /* |
356 | * If there are enough dots in the name, let's just give it a |
357 | * try 'as is'. The threshold can be set with the "ndots" option. |
358 | * Also, query 'as is', if there is a trailing dot in the name. |
359 | */ |
360 | saved_herrno = -1; |
361 | if (dots >= statp->ndots || trailing_dot) { |
362 | ret = __res_context_querydomain (ctx, name, NULL, class, type, |
363 | answer, anslen, answerp, |
364 | answerp2, nanswerp2, resplen2, |
365 | answerp2_malloced); |
366 | if (ret > 0 || trailing_dot |
367 | /* If the second response is valid then we use that. */ |
368 | || (ret == 0 && resplen2 != NULL && *resplen2 > 0)) |
369 | return (ret); |
370 | saved_herrno = h_errno; |
371 | tried_as_is++; |
372 | if (answerp && *answerp != answer) { |
373 | answer = *answerp; |
374 | anslen = MAXPACKET; |
375 | } |
376 | if (answerp2 && *answerp2_malloced) |
377 | { |
378 | free (*answerp2); |
379 | *answerp2 = NULL; |
380 | *nanswerp2 = 0; |
381 | *answerp2_malloced = 0; |
382 | } |
383 | } |
384 | |
385 | /* |
386 | * We do at least one level of search if |
387 | * - there is no dot and RES_DEFNAME is set, or |
388 | * - there is at least one dot, there is no trailing dot, |
389 | * and RES_DNSRCH is set. |
390 | */ |
391 | if ((!dots && (statp->options & RES_DEFNAMES) != 0) || |
392 | (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) { |
393 | int done = 0; |
394 | |
395 | for (size_t domain_index = 0; !done; ++domain_index) { |
396 | const char *dname = __resolv_context_search_list |
397 | (ctx, domain_index); |
398 | if (dname == NULL) |
399 | break; |
400 | searched = 1; |
401 | |
402 | /* __res_context_querydoman concatenates name |
403 | with dname with a "." in between. If we |
404 | pass it in dname the "." we got from the |
405 | configured default search path, we'll end |
406 | up with "name..", which won't resolve. |
407 | OTOH, passing it "" will result in "name.", |
408 | which has the intended effect for both |
409 | possible representations of the root |
410 | domain. */ |
411 | if (dname[0] == '.') |
412 | dname++; |
413 | if (dname[0] == '\0') |
414 | root_on_list++; |
415 | |
416 | ret = __res_context_querydomain |
417 | (ctx, name, dname, class, type, |
418 | answer, anslen, answerp, answerp2, nanswerp2, |
419 | resplen2, answerp2_malloced); |
420 | if (ret > 0 || (ret == 0 && resplen2 != NULL |
421 | && *resplen2 > 0)) |
422 | return (ret); |
423 | |
424 | if (answerp && *answerp != answer) { |
425 | answer = *answerp; |
426 | anslen = MAXPACKET; |
427 | } |
428 | if (answerp2 && *answerp2_malloced) |
429 | { |
430 | free (*answerp2); |
431 | *answerp2 = NULL; |
432 | *nanswerp2 = 0; |
433 | *answerp2_malloced = 0; |
434 | } |
435 | |
436 | /* |
437 | * If no server present, give up. |
438 | * If name isn't found in this domain, |
439 | * keep trying higher domains in the search list |
440 | * (if that's enabled). |
441 | * On a NO_DATA error, keep trying, otherwise |
442 | * a wildcard entry of another type could keep us |
443 | * from finding this entry higher in the domain. |
444 | * If we get some other error (negative answer or |
445 | * server failure), then stop searching up, |
446 | * but try the input name below in case it's |
447 | * fully-qualified. |
448 | */ |
449 | if (errno == ECONNREFUSED) { |
450 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
451 | return (-1); |
452 | } |
453 | |
454 | switch (statp->res_h_errno) { |
455 | case NO_DATA: |
456 | got_nodata++; |
457 | /* FALLTHROUGH */ |
458 | case HOST_NOT_FOUND: |
459 | /* keep trying */ |
460 | break; |
461 | case TRY_AGAIN: |
462 | if (hp->rcode == SERVFAIL) { |
463 | /* try next search element, if any */ |
464 | got_servfail++; |
465 | break; |
466 | } |
467 | /* FALLTHROUGH */ |
468 | default: |
469 | /* anything else implies that we're done */ |
470 | done++; |
471 | } |
472 | |
473 | /* if we got here for some reason other than DNSRCH, |
474 | * we only wanted one iteration of the loop, so stop. |
475 | */ |
476 | if ((statp->options & RES_DNSRCH) == 0) |
477 | done++; |
478 | } |
479 | } |
480 | |
481 | /* |
482 | * If the query has not already been tried as is then try it |
483 | * unless RES_NOTLDQUERY is set and there were no dots. |
484 | */ |
485 | if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0) |
486 | && !(tried_as_is || root_on_list)) { |
487 | ret = __res_context_querydomain |
488 | (ctx, name, NULL, class, type, |
489 | answer, anslen, answerp, answerp2, nanswerp2, |
490 | resplen2, answerp2_malloced); |
491 | if (ret > 0 || (ret == 0 && resplen2 != NULL |
492 | && *resplen2 > 0)) |
493 | return (ret); |
494 | } |
495 | |
496 | /* if we got here, we didn't satisfy the search. |
497 | * if we did an initial full query, return that query's H_ERRNO |
498 | * (note that we wouldn't be here if that query had succeeded). |
499 | * else if we ever got a nodata, send that back as the reason. |
500 | * else send back meaningless H_ERRNO, that being the one from |
501 | * the last DNSRCH we did. |
502 | */ |
503 | if (answerp2 && *answerp2_malloced) |
504 | { |
505 | free (*answerp2); |
506 | *answerp2 = NULL; |
507 | *nanswerp2 = 0; |
508 | *answerp2_malloced = 0; |
509 | } |
510 | if (saved_herrno != -1) |
511 | RES_SET_H_ERRNO(statp, saved_herrno); |
512 | else if (got_nodata) |
513 | RES_SET_H_ERRNO(statp, NO_DATA); |
514 | else if (got_servfail) |
515 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
516 | return (-1); |
517 | } |
518 | libresolv_hidden_def (__res_context_search) |
519 | |
520 | /* Common part of res_nsearch and res_search. */ |
521 | static int |
522 | context_search_common (struct resolv_context *ctx, |
523 | const char *name, int class, int type, |
524 | unsigned char *answer, int anslen) |
525 | { |
526 | if (ctx == NULL) |
527 | { |
528 | RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
529 | return -1; |
530 | } |
531 | int result = __res_context_search (ctx, name, class, type, answer, anslen, |
532 | NULL, NULL, NULL, NULL, NULL); |
533 | __resolv_context_put (ctx); |
534 | return result; |
535 | } |
536 | |
537 | int |
538 | res_nsearch(res_state statp, |
539 | const char *name, /* domain name */ |
540 | int class, int type, /* class and type of query */ |
541 | u_char *answer, /* buffer to put answer */ |
542 | int anslen) /* size of answer */ |
543 | { |
544 | return context_search_common |
545 | (__resolv_context_get_override (statp), name, class, type, answer, anslen); |
546 | } |
547 | |
548 | int |
549 | res_search (const char *name, int class, int type, |
550 | unsigned char *answer, int anslen) |
551 | { |
552 | return context_search_common |
553 | (__resolv_context_get (), name, class, type, answer, anslen); |
554 | } |
555 | |
556 | /* Perform a call on res_query on the concatenation of name and |
557 | domain. */ |
558 | static int |
559 | __res_context_querydomain (struct resolv_context *ctx, |
560 | const char *name, const char *domain, |
561 | int class, int type, |
562 | unsigned char *answer, int anslen, |
563 | unsigned char **answerp, unsigned char **answerp2, |
564 | int *nanswerp2, int *resplen2, |
565 | int *answerp2_malloced) |
566 | { |
567 | struct __res_state *statp = ctx->resp; |
568 | char nbuf[MAXDNAME]; |
569 | const char *longname = nbuf; |
570 | size_t n, d; |
571 | |
572 | if (domain == NULL) { |
573 | n = strlen(name); |
574 | |
575 | /* Decrement N prior to checking it against MAXDNAME |
576 | so that we detect a wrap to SIZE_MAX and return |
577 | a reasonable error. */ |
578 | n--; |
579 | if (n >= MAXDNAME - 1) { |
580 | RES_SET_H_ERRNO(statp, NO_RECOVERY); |
581 | return (-1); |
582 | } |
583 | longname = name; |
584 | } else { |
585 | n = strlen(name); |
586 | d = strlen(domain); |
587 | if (n + d + 1 >= MAXDNAME) { |
588 | RES_SET_H_ERRNO(statp, NO_RECOVERY); |
589 | return (-1); |
590 | } |
591 | sprintf(nbuf, "%s.%s" , name, domain); |
592 | } |
593 | return __res_context_query (ctx, longname, class, type, answer, |
594 | anslen, answerp, answerp2, nanswerp2, |
595 | resplen2, answerp2_malloced); |
596 | } |
597 | |
598 | /* Common part of res_nquerydomain and res_querydomain. */ |
599 | static int |
600 | context_querydomain_common (struct resolv_context *ctx, |
601 | const char *name, const char *domain, |
602 | int class, int type, |
603 | unsigned char *answer, int anslen) |
604 | { |
605 | if (ctx == NULL) |
606 | { |
607 | RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
608 | return -1; |
609 | } |
610 | int result = __res_context_querydomain (ctx, name, domain, class, type, |
611 | answer, anslen, |
612 | NULL, NULL, NULL, NULL, NULL); |
613 | __resolv_context_put (ctx); |
614 | return result; |
615 | } |
616 | |
617 | int |
618 | res_nquerydomain(res_state statp, |
619 | const char *name, |
620 | const char *domain, |
621 | int class, int type, /* class and type of query */ |
622 | u_char *answer, /* buffer to put answer */ |
623 | int anslen) /* size of answer */ |
624 | { |
625 | return context_querydomain_common |
626 | (__resolv_context_get_override (statp), |
627 | name, domain, class, type, answer, anslen); |
628 | } |
629 | |
630 | int |
631 | res_querydomain (const char *name, const char *domain, int class, int type, |
632 | unsigned char *answer, int anslen) |
633 | { |
634 | return context_querydomain_common |
635 | (__resolv_context_get (), name, domain, class, type, answer, anslen); |
636 | } |
637 | |
638 | const char * |
639 | __res_context_hostalias (struct resolv_context *ctx, |
640 | const char *name, char *dst, size_t siz) |
641 | { |
642 | char *file, *cp1, *cp2; |
643 | char buf[BUFSIZ]; |
644 | FILE *fp; |
645 | |
646 | if (ctx->resp->options & RES_NOALIASES) |
647 | return (NULL); |
648 | file = getenv("HOSTALIASES" ); |
649 | if (file == NULL || (fp = fopen(file, "rce" )) == NULL) |
650 | return (NULL); |
651 | setbuf(fp, NULL); |
652 | buf[sizeof(buf) - 1] = '\0'; |
653 | while (fgets(buf, sizeof(buf), fp)) { |
654 | for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1) |
655 | ; |
656 | if (!*cp1) |
657 | break; |
658 | *cp1 = '\0'; |
659 | if (ns_samename(buf, name) == 1) { |
660 | while (isspace(*++cp1)) |
661 | ; |
662 | if (!*cp1) |
663 | break; |
664 | for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2) |
665 | ; |
666 | *cp2 = '\0'; |
667 | strncpy(dst, cp1, siz - 1); |
668 | dst[siz - 1] = '\0'; |
669 | fclose(fp); |
670 | return (dst); |
671 | } |
672 | } |
673 | fclose(fp); |
674 | return (NULL); |
675 | } |
676 | libresolv_hidden_def (__res_context_hostalias) |
677 | |
678 | /* Common part of res_hostalias and hostalias. */ |
679 | static const char * |
680 | context_hostalias_common (struct resolv_context *ctx, |
681 | const char *name, char *dst, size_t siz) |
682 | { |
683 | if (ctx == NULL) |
684 | { |
685 | RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
686 | return NULL; |
687 | } |
688 | const char *result = __res_context_hostalias (ctx, name, dst, siz); |
689 | __resolv_context_put (ctx); |
690 | return result; |
691 | } |
692 | |
693 | const char * |
694 | res_hostalias (res_state statp, const char *name, char *dst, size_t siz) |
695 | { |
696 | return context_hostalias_common |
697 | (__resolv_context_get_override (statp), name, dst, siz); |
698 | } |
699 | |
700 | const char * |
701 | hostalias (const char *name) |
702 | { |
703 | static char abuf[MAXDNAME]; |
704 | return context_hostalias_common |
705 | (__resolv_context_get (), name, abuf, sizeof (abuf)); |
706 | } |
707 | |
708 | #if SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2) |
709 | # undef res_query |
710 | # undef res_querydomain |
711 | # undef res_search |
712 | weak_alias (__res_query, res_query); |
713 | weak_alias (__res_querydomain, res_querydomain); |
714 | weak_alias (__res_search, res_search); |
715 | #endif |
716 | |