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
49 #define ALIGNBYTES (sizeof(uintptr_t) - 1)
50 #define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) & ~ALIGNBYTES)
51
sethostent_r(FILE ** hf)52 static void sethostent_r(FILE** hf) {
53 if (!*hf)
54 *hf = fopen(_PATH_HOSTS, "re");
55 else
56 rewind(*hf);
57 }
58
endhostent_r(FILE ** hf)59 static void endhostent_r(FILE** hf) {
60 if (*hf) {
61 (void) fclose(*hf);
62 *hf = NULL;
63 }
64 }
65
66 // TODO: Consider returning a boolean result as files_getaddrinfo() does because the error code
67 // does not currently return to netd.
_hf_gethtbyname2(const char * name,int af,getnamaddr * info)68 int _hf_gethtbyname2(const char* name, int af, getnamaddr* info) {
69 struct hostent *hp, hent;
70 char *buf, *ptr;
71 size_t len, num, i;
72 char* aliases[MAXALIASES];
73 char* addr_ptrs[MAXADDRS];
74
75 FILE* hf = NULL;
76 sethostent_r(&hf);
77 if (hf == NULL) {
78 // TODO: Consider converting to a private extended EAI_* error code.
79 // Currently, the EAI_* value has no corresponding error code for invalid argument socket
80 // length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM
81 // and EINVAL, to EAI_FAIL.
82 return EAI_FAIL;
83 }
84
85 if ((ptr = buf = (char*) malloc(len = info->buflen)) == NULL) {
86 return EAI_MEMORY;
87 }
88
89 hent.h_name = NULL;
90 hent.h_addrtype = 0;
91 hent.h_length = 0;
92
93 size_t anum = 0;
94 for (num = 0; num < MAXADDRS; /**/) {
95 info->hp->h_addrtype = af;
96 info->hp->h_length = 0;
97
98 int he;
99 hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen, &he);
100 if (hp == NULL) {
101 if (he == NETDB_INTERNAL && errno == ENOSPC) {
102 goto nospc; // glibc compatibility.
103 }
104 break;
105 }
106
107 if (strcasecmp(hp->h_name, name) != 0) {
108 char** cp;
109 for (cp = hp->h_aliases; *cp != NULL; cp++)
110 if (strcasecmp(*cp, name) == 0) break;
111 // NOTE: does not increment num
112 if (*cp == NULL) continue;
113 }
114
115 if (num == 0) {
116 hent.h_addrtype = hp->h_addrtype;
117 hent.h_length = hp->h_length;
118
119 HENT_SCOPY(hent.h_name, hp->h_name, ptr, len);
120 for (anum = 0; hp->h_aliases[anum]; anum++) {
121 if (anum >= MAXALIASES) goto nospc;
122 HENT_SCOPY(aliases[anum], hp->h_aliases[anum], ptr, len);
123 }
124 ptr = (char*) ALIGN(ptr);
125 if ((size_t)(ptr - buf) >= info->buflen) goto nospc;
126 }
127
128 if (num >= MAXADDRS) goto nospc;
129 HENT_COPY(addr_ptrs[num], hp->h_addr_list[0], hp->h_length, ptr, len);
130
131 num++;
132 }
133 endhostent_r(&hf);
134
135 if (num == 0) {
136 free(buf);
137 // TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead.
138 // The original return error number is h_errno HOST_NOT_FOUND which was converted to
139 // EAI_NODATA.
140 return EAI_NODATA;
141 }
142
143 hp = info->hp;
144 ptr = info->buf;
145 len = info->buflen;
146
147 hp->h_addrtype = hent.h_addrtype;
148 hp->h_length = hent.h_length;
149
150 HENT_ARRAY(hp->h_aliases, anum, ptr, len);
151 HENT_ARRAY(hp->h_addr_list, num, ptr, len);
152
153 for (i = 0; i < num; i++) {
154 HENT_COPY(hp->h_addr_list[i], addr_ptrs[i], hp->h_length, ptr, len);
155
156 // reserve space for mapping IPv4 address to IPv6 address in place
157 if (hp->h_addrtype == AF_INET) {
158 HENT_COPY(ptr, NAT64_PAD, sizeof(NAT64_PAD), ptr, len);
159 }
160 }
161 hp->h_addr_list[num] = NULL;
162
163 HENT_SCOPY(hp->h_name, hent.h_name, ptr, len);
164
165 for (i = 0; i < anum; i++) {
166 HENT_SCOPY(hp->h_aliases[i], aliases[i], ptr, len);
167 }
168 hp->h_aliases[anum] = NULL;
169
170 free(buf);
171 return 0;
172 nospc:
173 free(buf);
174 return EAI_MEMORY;
175 }
176
177 // TODO: Consider returning a boolean result as files_getaddrinfo() does because the error code
178 // does not currently return to netd.
_hf_gethtbyaddr(const unsigned char * uaddr,int len,int af,getnamaddr * info)179 int _hf_gethtbyaddr(const unsigned char* uaddr, int len, int af, getnamaddr* info) {
180 info->hp->h_length = len;
181 info->hp->h_addrtype = af;
182
183 FILE* hf = NULL;
184 sethostent_r(&hf);
185 if (hf == NULL) {
186 // TODO: Consider converting to a private extended EAI_* error code.
187 // Currently, the EAI_* value has no corresponding error code for invalid argument socket
188 // length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM
189 // and EINVAL, to EAI_FAIL.
190 return EAI_FAIL;
191 }
192 struct hostent* hp;
193 int he;
194 while ((hp = netbsd_gethostent_r(hf, info->hp, info->buf, info->buflen, &he)) != NULL)
195 if (!memcmp(hp->h_addr_list[0], uaddr, (size_t) hp->h_length)) break;
196 endhostent_r(&hf);
197
198 if (hp == NULL) {
199 if (errno == ENOSPC) return EAI_MEMORY; // glibc compatibility.
200 // TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead.
201 // The original return error number is h_errno HOST_NOT_FOUND which was converted to
202 // EAI_NODATA.
203 return EAI_NODATA;
204 }
205 return 0;
206 }
207