1 /* $NetBSD: sethostent.c,v 1.20 2014/03/17 13:24:23 christos Exp $ */
2
3 /*
4 * Copyright (c) 1985, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <arpa/inet.h>
33 #include <arpa/nameser.h>
34 #include <assert.h>
35 #include <errno.h>
36 #include <netdb.h>
37 #include <netinet/in.h>
38 #include <resolv.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <sys/param.h>
42
43 #include "hostent.h"
44 #include "resolv_private.h"
45
46 constexpr int MAXALIASES = 35;
47 constexpr int MAXADDRS = 35;
48
sethostent_r(FILE ** hf)49 static void sethostent_r(FILE** hf) {
50 if (!*hf)
51 *hf = fopen(_PATH_HOSTS, "re");
52 else
53 rewind(*hf);
54 }
55
endhostent_r(FILE ** hf)56 static void endhostent_r(FILE** hf) {
57 if (*hf) {
58 (void) fclose(*hf);
59 *hf = NULL;
60 }
61 }
62
63 // TODO: Consider returning a boolean result as files_getaddrinfo() does because the error code
64 // does not currently return to netd.
_hf_gethtbyname2(const char * name,int af,getnamaddr * info)65 int _hf_gethtbyname2(const char* name, int af, getnamaddr* info) {
66 struct hostent *hp, hent;
67 char *buf, *ptr;
68 size_t len, num, i;
69 char* aliases[MAXALIASES];
70 char* addr_ptrs[MAXADDRS];
71
72 FILE* hf = NULL;
73 sethostent_r(&hf);
74 if (hf == NULL) {
75 // TODO: Consider converting to a private extended EAI_* error code.
76 // Currently, the EAI_* value has no corresponding error code for invalid argument socket
77 // length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM
78 // and EINVAL, to EAI_FAIL.
79 return EAI_FAIL;
80 }
81
82 if ((ptr = buf = (char*) malloc(len = info->buflen)) == NULL) {
83 return EAI_MEMORY;
84 }
85
86 hent.h_name = NULL;
87 hent.h_addrtype = 0;
88 hent.h_length = 0;
89
90 size_t anum = 0;
91 for (num = 0; num < MAXADDRS; /**/) {
92 info->hp->h_addrtype = af;
93 info->hp->h_length = 0;
94
95 int he;
96 hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen, &he);
97 if (hp == NULL) {
98 if (he == NETDB_INTERNAL && errno == ENOSPC) {
99 goto nospc; // glibc compatibility.
100 }
101 break;
102 }
103
104 if (strcasecmp(hp->h_name, name) != 0) {
105 char** cp;
106 for (cp = hp->h_aliases; *cp != NULL; cp++)
107 if (strcasecmp(*cp, name) == 0) break;
108 // NOTE: does not increment num
109 if (*cp == NULL) continue;
110 }
111
112 if (num == 0) {
113 hent.h_addrtype = hp->h_addrtype;
114 hent.h_length = hp->h_length;
115
116 HENT_SCOPY(hent.h_name, hp->h_name, ptr, len);
117 for (anum = 0; hp->h_aliases[anum]; anum++) {
118 if (anum >= MAXALIASES) goto nospc;
119 HENT_SCOPY(aliases[anum], hp->h_aliases[anum], ptr, len);
120 }
121 ptr = align_ptr(ptr);
122 if ((size_t)(ptr - buf) >= info->buflen) goto nospc;
123 }
124
125 if (num >= MAXADDRS) goto nospc;
126 HENT_COPY(addr_ptrs[num], hp->h_addr_list[0], hp->h_length, ptr, len);
127
128 num++;
129 }
130 endhostent_r(&hf);
131
132 if (num == 0) {
133 free(buf);
134 // TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead.
135 // The original return error number is h_errno HOST_NOT_FOUND which was converted to
136 // EAI_NODATA.
137 return EAI_NODATA;
138 }
139
140 hp = info->hp;
141 ptr = info->buf;
142 len = info->buflen;
143
144 hp->h_addrtype = hent.h_addrtype;
145 hp->h_length = hent.h_length;
146
147 HENT_ARRAY(hp->h_aliases, anum, ptr, len);
148 HENT_ARRAY(hp->h_addr_list, num, ptr, len);
149
150 for (i = 0; i < num; i++) {
151 HENT_COPY(hp->h_addr_list[i], addr_ptrs[i], hp->h_length, ptr, len);
152
153 // reserve space for mapping IPv4 address to IPv6 address in place
154 if (hp->h_addrtype == AF_INET) {
155 HENT_COPY(ptr, NAT64_PAD, sizeof(NAT64_PAD), ptr, len);
156 }
157 }
158 hp->h_addr_list[num] = NULL;
159
160 HENT_SCOPY(hp->h_name, hent.h_name, ptr, len);
161
162 for (i = 0; i < anum; i++) {
163 HENT_SCOPY(hp->h_aliases[i], aliases[i], ptr, len);
164 }
165 hp->h_aliases[anum] = NULL;
166
167 free(buf);
168 return 0;
169 nospc:
170 free(buf);
171 return EAI_MEMORY;
172 }
173
174 // TODO: Consider returning a boolean result as files_getaddrinfo() does because the error code
175 // does not currently return to netd.
_hf_gethtbyaddr(const unsigned char * uaddr,int len,int af,getnamaddr * info)176 int _hf_gethtbyaddr(const unsigned char* uaddr, int len, int af, getnamaddr* info) {
177 info->hp->h_length = len;
178 info->hp->h_addrtype = af;
179
180 FILE* hf = NULL;
181 sethostent_r(&hf);
182 if (hf == NULL) {
183 // TODO: Consider converting to a private extended EAI_* error code.
184 // Currently, the EAI_* value has no corresponding error code for invalid argument socket
185 // length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM
186 // and EINVAL, to EAI_FAIL.
187 return EAI_FAIL;
188 }
189 struct hostent* hp;
190 int he;
191 while ((hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen, &he)) != NULL)
192 if (!memcmp(hp->h_addr_list[0], uaddr, (size_t) hp->h_length)) break;
193 endhostent_r(&hf);
194
195 if (hp == NULL) {
196 if (errno == ENOSPC) return EAI_MEMORY; // glibc compatibility.
197 // TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead.
198 // The original return error number is h_errno HOST_NOT_FOUND which was converted to
199 // EAI_NODATA.
200 return EAI_NODATA;
201 }
202 return 0;
203 }
204