| /* |
| * Copyright (c) 1988, 1993 |
| * The Regents of the University of California. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 4. Neither the name of the University nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| /* |
| * Portions Copyright (c) 1993 by Digital Equipment Corporation. |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies, and that |
| * the name of Digital Equipment Corporation not be used in advertising or |
| * publicity pertaining to distribution of the document or software without |
| * specific, written prior permission. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL |
| * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT |
| * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
| * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
| * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
| * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
| * SOFTWARE. |
| */ |
| |
| /* |
| * Portions Copyright (c) 1996-1999 by Internet Software Consortium. |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
| * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
| * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
| * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
| * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
| * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
| * SOFTWARE. |
| */ |
| |
| #include <assert.h> |
| #include <sys/types.h> |
| #include <sys/param.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| #include <arpa/nameser.h> |
| #include <ctype.h> |
| #include <errno.h> |
| #include <netdb.h> |
| #include <resolv.h> |
| #include <resolv/resolv-internal.h> |
| #include <resolv/resolv_context.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <shlib-compat.h> |
| |
| #if PACKETSZ > 65536 |
| #define MAXPACKET PACKETSZ |
| #else |
| #define MAXPACKET 65536 |
| #endif |
| |
| #define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1) |
| |
| static int |
| __res_context_querydomain (struct resolv_context *, |
| const char *name, const char *domain, |
| int class, int type, unsigned char *answer, int anslen, |
| unsigned char **answerp, unsigned char **answerp2, int *nanswerp2, |
| int *resplen2, int *answerp2_malloced); |
| |
| /* Formulate a normal query, send, and await answer. Returned answer |
| is placed in supplied buffer ANSWER. Perform preliminary check of |
| answer, returning success only if no error is indicated and the |
| answer count is nonzero. Return the size of the response on |
| success, -1 on error. Error number is left in h_errno. |
| |
| Caller must parse answer and determine whether it answers the |
| question. */ |
| int |
| __res_context_query (struct resolv_context *ctx, const char *name, |
| int class, int type, |
| unsigned char *answer, int anslen, |
| unsigned char **answerp, unsigned char **answerp2, |
| int *nanswerp2, int *resplen2, int *answerp2_malloced) |
| { |
| struct __res_state *statp = ctx->resp; |
| HEADER *hp = (HEADER *) answer; |
| HEADER *hp2; |
| int n, use_malloc = 0; |
| |
| size_t bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * QUERYSIZE; |
| u_char *buf = alloca (bufsize); |
| u_char *query1 = buf; |
| int nquery1 = -1; |
| u_char *query2 = NULL; |
| int nquery2 = 0; |
| |
| again: |
| hp->rcode = NOERROR; /* default */ |
| |
| if (type == T_QUERY_A_AND_AAAA) |
| { |
| n = __res_context_mkquery (ctx, QUERY, name, class, T_A, NULL, |
| query1, bufsize); |
| if (n > 0) |
| { |
| if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) |
| { |
| /* Use RESOLV_EDNS_BUFFER_SIZE because the receive |
| buffer can be reallocated. */ |
| n = __res_nopt (ctx, n, query1, bufsize, |
| RESOLV_EDNS_BUFFER_SIZE); |
| if (n < 0) |
| goto unspec_nomem; |
| } |
| |
| nquery1 = n; |
| /* Align the buffer. */ |
| int npad = ((nquery1 + __alignof__ (HEADER) - 1) |
| & ~(__alignof__ (HEADER) - 1)) - nquery1; |
| if (n > bufsize - npad) |
| { |
| n = -1; |
| goto unspec_nomem; |
| } |
| int nused = n + npad; |
| query2 = buf + nused; |
| n = __res_context_mkquery (ctx, QUERY, name, class, T_AAAA, |
| NULL, query2, bufsize - nused); |
| if (n > 0 |
| && (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) |
| /* Use RESOLV_EDNS_BUFFER_SIZE because the receive |
| buffer can be reallocated. */ |
| n = __res_nopt (ctx, n, query2, bufsize, |
| RESOLV_EDNS_BUFFER_SIZE); |
| nquery2 = n; |
| } |
| |
| unspec_nomem:; |
| } |
| else |
| { |
| n = __res_context_mkquery (ctx, QUERY, name, class, type, NULL, |
| query1, bufsize); |
| |
| if (n > 0 |
| && (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) |
| { |
| /* Use RESOLV_EDNS_BUFFER_SIZE if the receive buffer |
| can be reallocated. */ |
| size_t advertise; |
| if (answerp == NULL) |
| advertise = anslen; |
| else |
| advertise = RESOLV_EDNS_BUFFER_SIZE; |
| n = __res_nopt (ctx, n, query1, bufsize, advertise); |
| } |
| |
| nquery1 = n; |
| } |
| |
| if (__glibc_unlikely (n <= 0) && !use_malloc) { |
| /* Retry just in case res_nmkquery failed because of too |
| short buffer. Shouldn't happen. */ |
| bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * MAXPACKET; |
| buf = malloc (bufsize); |
| if (buf != NULL) { |
| query1 = buf; |
| use_malloc = 1; |
| goto again; |
| } |
| } |
| if (__glibc_unlikely (n <= 0)) { |
| RES_SET_H_ERRNO(statp, NO_RECOVERY); |
| if (use_malloc) |
| free (buf); |
| return (n); |
| } |
| assert (answerp == NULL || (void *) *answerp == (void *) answer); |
| n = __res_context_send (ctx, query1, nquery1, query2, nquery2, answer, |
| anslen, answerp, answerp2, nanswerp2, resplen2, |
| answerp2_malloced); |
| if (use_malloc) |
| free (buf); |
| if (n < 0) { |
| RES_SET_H_ERRNO(statp, TRY_AGAIN); |
| return (n); |
| } |
| |
| if (answerp != NULL) |
| /* __res_context_send might have reallocated the buffer. */ |
| hp = (HEADER *) *answerp; |
| |
| /* We simplify the following tests by assigning HP to HP2 or |
| vice versa. It is easy to verify that this is the same as |
| ignoring all tests of HP or HP2. */ |
| if (answerp2 == NULL || *resplen2 < (int) sizeof (HEADER)) |
| { |
| hp2 = hp; |
| } |
| else |
| { |
| hp2 = (HEADER *) *answerp2; |
| if (n < (int) sizeof (HEADER)) |
| { |
| hp = hp2; |
| } |
| } |
| |
| /* Make sure both hp and hp2 are defined */ |
| assert((hp != NULL) && (hp2 != NULL)); |
| |
| if ((hp->rcode != NOERROR || ntohs(hp->ancount) == 0) |
| && (hp2->rcode != NOERROR || ntohs(hp2->ancount) == 0)) { |
| switch (hp->rcode == NOERROR ? hp2->rcode : hp->rcode) { |
| case NXDOMAIN: |
| if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0) |
| || (hp2->rcode == NOERROR |
| && ntohs (hp2->ancount) != 0)) |
| goto success; |
| RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); |
| break; |
| case SERVFAIL: |
| RES_SET_H_ERRNO(statp, TRY_AGAIN); |
| break; |
| case NOERROR: |
| if (ntohs (hp->ancount) != 0 |
| || ntohs (hp2->ancount) != 0) |
| goto success; |
| RES_SET_H_ERRNO(statp, NO_DATA); |
| break; |
| case FORMERR: |
| case NOTIMP: |
| /* Servers must not reply to AAAA queries with |
| NOTIMP etc but some of them do. */ |
| if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0) |
| || (hp2->rcode == NOERROR |
| && ntohs (hp2->ancount) != 0)) |
| goto success; |
| /* FALLTHROUGH */ |
| case REFUSED: |
| default: |
| RES_SET_H_ERRNO(statp, NO_RECOVERY); |
| break; |
| } |
| return (-1); |
| } |
| success: |
| return (n); |
| } |
| libresolv_hidden_def (__res_context_query) |
| |
| /* Common part of res_nquery and res_query. */ |
| static int |
| context_query_common (struct resolv_context *ctx, |
| const char *name, int class, int type, |
| unsigned char *answer, int anslen) |
| { |
| if (ctx == NULL) |
| { |
| RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
| return -1; |
| } |
| int result = __res_context_query (ctx, name, class, type, answer, anslen, |
| NULL, NULL, NULL, NULL, NULL); |
| __resolv_context_put (ctx); |
| return result; |
| } |
| |
| int |
| res_nquery(res_state statp, |
| const char *name, /* domain name */ |
| int class, int type, /* class and type of query */ |
| u_char *answer, /* buffer to put answer */ |
| int anslen) /* size of answer buffer */ |
| { |
| return context_query_common |
| (__resolv_context_get_override (statp), name, class, type, answer, anslen); |
| } |
| |
| int |
| res_query (const char *name, int class, int type, |
| unsigned char *answer, int anslen) |
| { |
| return context_query_common |
| (__resolv_context_get (), name, class, type, answer, anslen); |
| } |
| |
| /* Formulate a normal query, send, and retrieve answer in supplied |
| buffer. Return the size of the response on success, -1 on error. |
| If enabled, implement search rules until answer or unrecoverable |
| failure is detected. Error code, if any, is left in h_errno. */ |
| int |
| __res_context_search (struct resolv_context *ctx, |
| const char *name, int class, int type, |
| unsigned char *answer, int anslen, |
| unsigned char **answerp, unsigned char **answerp2, |
| int *nanswerp2, int *resplen2, int *answerp2_malloced) |
| { |
| struct __res_state *statp = ctx->resp; |
| const char *cp; |
| HEADER *hp = (HEADER *) answer; |
| char tmp[NS_MAXDNAME]; |
| u_int dots; |
| int trailing_dot, ret, saved_herrno; |
| int got_nodata = 0, got_servfail = 0, root_on_list = 0; |
| int tried_as_is = 0; |
| int searched = 0; |
| |
| __set_errno (0); |
| RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */ |
| |
| dots = 0; |
| for (cp = name; *cp != '\0'; cp++) |
| dots += (*cp == '.'); |
| trailing_dot = 0; |
| if (cp > name && *--cp == '.') |
| trailing_dot++; |
| |
| /* If there aren't any dots, it could be a user-level alias. */ |
| if (!dots && (cp = __res_context_hostalias |
| (ctx, name, tmp, sizeof tmp))!= NULL) |
| return __res_context_query (ctx, cp, class, type, answer, |
| anslen, answerp, answerp2, |
| nanswerp2, resplen2, answerp2_malloced); |
| |
| /* |
| * If there are enough dots in the name, let's just give it a |
| * try 'as is'. The threshold can be set with the "ndots" option. |
| * Also, query 'as is', if there is a trailing dot in the name. |
| */ |
| saved_herrno = -1; |
| if (dots >= statp->ndots || trailing_dot) { |
| ret = __res_context_querydomain (ctx, name, NULL, class, type, |
| answer, anslen, answerp, |
| answerp2, nanswerp2, resplen2, |
| answerp2_malloced); |
| if (ret > 0 || trailing_dot |
| /* If the second response is valid then we use that. */ |
| || (ret == 0 && resplen2 != NULL && *resplen2 > 0)) |
| return (ret); |
| saved_herrno = h_errno; |
| tried_as_is++; |
| if (answerp && *answerp != answer) { |
| answer = *answerp; |
| anslen = MAXPACKET; |
| } |
| if (answerp2 && *answerp2_malloced) |
| { |
| free (*answerp2); |
| *answerp2 = NULL; |
| *nanswerp2 = 0; |
| *answerp2_malloced = 0; |
| } |
| } |
| |
| /* |
| * We do at least one level of search if |
| * - there is no dot and RES_DEFNAME is set, or |
| * - there is at least one dot, there is no trailing dot, |
| * and RES_DNSRCH is set. |
| */ |
| if ((!dots && (statp->options & RES_DEFNAMES) != 0) || |
| (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) { |
| int done = 0; |
| |
| for (size_t domain_index = 0; !done; ++domain_index) { |
| const char *dname = __resolv_context_search_list |
| (ctx, domain_index); |
| if (dname == NULL) |
| break; |
| searched = 1; |
| |
| /* __res_context_querydoman concatenates name |
| with dname with a "." in between. If we |
| pass it in dname the "." we got from the |
| configured default search path, we'll end |
| up with "name..", which won't resolve. |
| OTOH, passing it "" will result in "name.", |
| which has the intended effect for both |
| possible representations of the root |
| domain. */ |
| if (dname[0] == '.') |
| dname++; |
| if (dname[0] == '\0') |
| root_on_list++; |
| |
| ret = __res_context_querydomain |
| (ctx, name, dname, class, type, |
| answer, anslen, answerp, answerp2, nanswerp2, |
| resplen2, answerp2_malloced); |
| if (ret > 0 || (ret == 0 && resplen2 != NULL |
| && *resplen2 > 0)) |
| return (ret); |
| |
| if (answerp && *answerp != answer) { |
| answer = *answerp; |
| anslen = MAXPACKET; |
| } |
| if (answerp2 && *answerp2_malloced) |
| { |
| free (*answerp2); |
| *answerp2 = NULL; |
| *nanswerp2 = 0; |
| *answerp2_malloced = 0; |
| } |
| |
| /* |
| * If no server present, give up. |
| * If name isn't found in this domain, |
| * keep trying higher domains in the search list |
| * (if that's enabled). |
| * On a NO_DATA error, keep trying, otherwise |
| * a wildcard entry of another type could keep us |
| * from finding this entry higher in the domain. |
| * If we get some other error (negative answer or |
| * server failure), then stop searching up, |
| * but try the input name below in case it's |
| * fully-qualified. |
| */ |
| if (errno == ECONNREFUSED) { |
| RES_SET_H_ERRNO(statp, TRY_AGAIN); |
| return (-1); |
| } |
| |
| switch (statp->res_h_errno) { |
| case NO_DATA: |
| got_nodata++; |
| /* FALLTHROUGH */ |
| case HOST_NOT_FOUND: |
| /* keep trying */ |
| break; |
| case TRY_AGAIN: |
| if (hp->rcode == SERVFAIL) { |
| /* try next search element, if any */ |
| got_servfail++; |
| break; |
| } |
| /* FALLTHROUGH */ |
| default: |
| /* anything else implies that we're done */ |
| done++; |
| } |
| |
| /* if we got here for some reason other than DNSRCH, |
| * we only wanted one iteration of the loop, so stop. |
| */ |
| if ((statp->options & RES_DNSRCH) == 0) |
| done++; |
| } |
| } |
| |
| /* |
| * If the query has not already been tried as is then try it |
| * unless RES_NOTLDQUERY is set and there were no dots. |
| */ |
| if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0) |
| && !(tried_as_is || root_on_list)) { |
| ret = __res_context_querydomain |
| (ctx, name, NULL, class, type, |
| answer, anslen, answerp, answerp2, nanswerp2, |
| resplen2, answerp2_malloced); |
| if (ret > 0 || (ret == 0 && resplen2 != NULL |
| && *resplen2 > 0)) |
| return (ret); |
| } |
| |
| /* if we got here, we didn't satisfy the search. |
| * if we did an initial full query, return that query's H_ERRNO |
| * (note that we wouldn't be here if that query had succeeded). |
| * else if we ever got a nodata, send that back as the reason. |
| * else send back meaningless H_ERRNO, that being the one from |
| * the last DNSRCH we did. |
| */ |
| if (answerp2 && *answerp2_malloced) |
| { |
| free (*answerp2); |
| *answerp2 = NULL; |
| *nanswerp2 = 0; |
| *answerp2_malloced = 0; |
| } |
| if (saved_herrno != -1) |
| RES_SET_H_ERRNO(statp, saved_herrno); |
| else if (got_nodata) |
| RES_SET_H_ERRNO(statp, NO_DATA); |
| else if (got_servfail) |
| RES_SET_H_ERRNO(statp, TRY_AGAIN); |
| return (-1); |
| } |
| libresolv_hidden_def (__res_context_search) |
| |
| /* Common part of res_nsearch and res_search. */ |
| static int |
| context_search_common (struct resolv_context *ctx, |
| const char *name, int class, int type, |
| unsigned char *answer, int anslen) |
| { |
| if (ctx == NULL) |
| { |
| RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
| return -1; |
| } |
| int result = __res_context_search (ctx, name, class, type, answer, anslen, |
| NULL, NULL, NULL, NULL, NULL); |
| __resolv_context_put (ctx); |
| return result; |
| } |
| |
| int |
| res_nsearch(res_state statp, |
| const char *name, /* domain name */ |
| int class, int type, /* class and type of query */ |
| u_char *answer, /* buffer to put answer */ |
| int anslen) /* size of answer */ |
| { |
| return context_search_common |
| (__resolv_context_get_override (statp), name, class, type, answer, anslen); |
| } |
| |
| int |
| res_search (const char *name, int class, int type, |
| unsigned char *answer, int anslen) |
| { |
| return context_search_common |
| (__resolv_context_get (), name, class, type, answer, anslen); |
| } |
| |
| /* Perform a call on res_query on the concatenation of name and |
| domain. */ |
| static int |
| __res_context_querydomain (struct resolv_context *ctx, |
| const char *name, const char *domain, |
| int class, int type, |
| unsigned char *answer, int anslen, |
| unsigned char **answerp, unsigned char **answerp2, |
| int *nanswerp2, int *resplen2, |
| int *answerp2_malloced) |
| { |
| struct __res_state *statp = ctx->resp; |
| char nbuf[MAXDNAME]; |
| const char *longname = nbuf; |
| size_t n, d; |
| |
| if (domain == NULL) { |
| n = strlen(name); |
| |
| /* Decrement N prior to checking it against MAXDNAME |
| so that we detect a wrap to SIZE_MAX and return |
| a reasonable error. */ |
| n--; |
| if (n >= MAXDNAME - 1) { |
| RES_SET_H_ERRNO(statp, NO_RECOVERY); |
| return (-1); |
| } |
| longname = name; |
| } else { |
| n = strlen(name); |
| d = strlen(domain); |
| if (n + d + 1 >= MAXDNAME) { |
| RES_SET_H_ERRNO(statp, NO_RECOVERY); |
| return (-1); |
| } |
| sprintf(nbuf, "%s.%s", name, domain); |
| } |
| return __res_context_query (ctx, longname, class, type, answer, |
| anslen, answerp, answerp2, nanswerp2, |
| resplen2, answerp2_malloced); |
| } |
| |
| /* Common part of res_nquerydomain and res_querydomain. */ |
| static int |
| context_querydomain_common (struct resolv_context *ctx, |
| const char *name, const char *domain, |
| int class, int type, |
| unsigned char *answer, int anslen) |
| { |
| if (ctx == NULL) |
| { |
| RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
| return -1; |
| } |
| int result = __res_context_querydomain (ctx, name, domain, class, type, |
| answer, anslen, |
| NULL, NULL, NULL, NULL, NULL); |
| __resolv_context_put (ctx); |
| return result; |
| } |
| |
| int |
| res_nquerydomain(res_state statp, |
| const char *name, |
| const char *domain, |
| int class, int type, /* class and type of query */ |
| u_char *answer, /* buffer to put answer */ |
| int anslen) /* size of answer */ |
| { |
| return context_querydomain_common |
| (__resolv_context_get_override (statp), |
| name, domain, class, type, answer, anslen); |
| } |
| |
| int |
| res_querydomain (const char *name, const char *domain, int class, int type, |
| unsigned char *answer, int anslen) |
| { |
| return context_querydomain_common |
| (__resolv_context_get (), name, domain, class, type, answer, anslen); |
| } |
| |
| const char * |
| __res_context_hostalias (struct resolv_context *ctx, |
| const char *name, char *dst, size_t siz) |
| { |
| char *file, *cp1, *cp2; |
| char buf[BUFSIZ]; |
| FILE *fp; |
| |
| if (ctx->resp->options & RES_NOALIASES) |
| return (NULL); |
| file = getenv("HOSTALIASES"); |
| if (file == NULL || (fp = fopen(file, "rce")) == NULL) |
| return (NULL); |
| setbuf(fp, NULL); |
| buf[sizeof(buf) - 1] = '\0'; |
| while (fgets(buf, sizeof(buf), fp)) { |
| for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1) |
| ; |
| if (!*cp1) |
| break; |
| *cp1 = '\0'; |
| if (ns_samename(buf, name) == 1) { |
| while (isspace(*++cp1)) |
| ; |
| if (!*cp1) |
| break; |
| for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2) |
| ; |
| *cp2 = '\0'; |
| strncpy(dst, cp1, siz - 1); |
| dst[siz - 1] = '\0'; |
| fclose(fp); |
| return (dst); |
| } |
| } |
| fclose(fp); |
| return (NULL); |
| } |
| libresolv_hidden_def (__res_context_hostalias) |
| |
| /* Common part of res_hostalias and hostalias. */ |
| static const char * |
| context_hostalias_common (struct resolv_context *ctx, |
| const char *name, char *dst, size_t siz) |
| { |
| if (ctx == NULL) |
| { |
| RES_SET_H_ERRNO (&_res, NETDB_INTERNAL); |
| return NULL; |
| } |
| const char *result = __res_context_hostalias (ctx, name, dst, siz); |
| __resolv_context_put (ctx); |
| return result; |
| } |
| |
| const char * |
| res_hostalias (res_state statp, const char *name, char *dst, size_t siz) |
| { |
| return context_hostalias_common |
| (__resolv_context_get_override (statp), name, dst, siz); |
| } |
| |
| const char * |
| hostalias (const char *name) |
| { |
| static char abuf[MAXDNAME]; |
| return context_hostalias_common |
| (__resolv_context_get (), name, abuf, sizeof (abuf)); |
| } |
| |
| #if SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2) |
| # undef res_query |
| # undef res_querydomain |
| # undef res_search |
| weak_alias (__res_query, res_query); |
| weak_alias (__res_querydomain, res_querydomain); |
| weak_alias (__res_search, res_search); |
| #endif |