1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI" /* SMI4.1 1.7 */
27
28 #include <stdio.h>
29 #include <ndbm.h>
30 #include <netdb.h>
31 #include <sys/types.h>
32 #include <sys/socket.h>
33 #include <netinet/in.h>
34 #include <arpa/inet.h>
35 #include <string.h>
36 #include <ctype.h>
37 #include <errno.h>
38
39 /*
40 * Filter to convert both IPv4 and IPv6 addresses from /etc/hosts file.
41 */
42
43 /*
44 * Size of buffer for input lines. Add two bytes on input for newline
45 * and terminating NULL. Note that the practical limit for data
46 * storage in ndbm is (PBLKSIZ - 3 * sizeof (short)). Though this
47 * differs from spec 1170 the common industry implementation does
48 * conform to this slightly lower limit.
49 */
50
51 #define OUTPUTSIZ (PBLKSIZ - 3 * sizeof (short))
52 #define INPUTSIZ (OUTPUTSIZ + 2)
53
54 static int ipv4 = -1;
55 static char *cmd;
56 int warning = 0;
57
58 static void verify_and_output(const char *key, char *value, int lineno);
59
60 void
usage()61 usage()
62 {
63 fprintf(stderr, "stdhosts [-w] [-n] [in-file]\n");
64 fprintf(stderr, "\t-w\tprint malformed warning messages.\n");
65 exit(1);
66 }
67
68 int
main(argc,argv)69 main(argc, argv)
70 char **argv;
71 {
72 char line[INPUTSIZ];
73 char adr[INPUTSIZ];
74 char nadr[INET6_ADDRSTRLEN]; /* Contains normalised address */
75 const char *nadrp; /* Pointer to the normalised address */
76 char *trailer;
77 char *commentp; /* Pointer to comment character '#' */
78 int c;
79 FILE *fp;
80 int lineno = 0; /* Input line counter */
81 struct in_addr in; /* Used for normalising the IPv4 address */
82 struct in6_addr in6; /* Used for normalising the IPv6 address */
83 char *fgetsp; /* Holds return value for fgets() calls */
84 int endoffile = 0; /* Set when end of file reached */
85
86 if (cmd = strrchr(argv[0], '/'))
87 ++cmd;
88 else
89 cmd = argv[0];
90
91 while ((c = getopt(argc, argv, "v:wn")) != -1) {
92 switch (c) {
93 case 'w': /* Send warning messages to stderr */
94 warning = 1;
95 break;
96 case 'n':
97 ipv4 = 0;
98 break;
99 default:
100 usage();
101 exit(1);
102 }
103 }
104
105 if (optind < argc) {
106 fp = fopen(argv[optind], "r");
107 if (fp == NULL) {
108 fprintf(stderr, "%s: can't open %s\n",
109 cmd, argv[optind]);
110 exit(1);
111 }
112 } else
113 fp = stdin;
114
115 while (!endoffile &&
116 (fgetsp = fgets(line, sizeof (line), fp)) != NULL) {
117 lineno++;
118
119 /* Check for comments */
120 if ((commentp = strchr(line, '#')) != NULL) {
121 if ((line[strlen(line) - 1] != '\n') &&
122 (strlen(line) >= (sizeof (line) - 1))) {
123 /*
124 * Discard the remainder of the line
125 * until the newline or EOF, then
126 * continue to parse the line. Use
127 * adr[] rather then line[] to
128 * preserve the contents of line[].
129 */
130 while ((fgetsp = fgets(adr, sizeof (adr),
131 fp)) != NULL) {
132 if (adr[strlen(adr) - 1] == '\n')
133 break;
134 }
135 if (fgetsp == NULL)
136 endoffile = 1;
137 }
138 /* Terminate line[] at the comment character */
139 *commentp = '\0';
140 } else if ((line[strlen(line) - 1] != '\n') &&
141 (strlen(line) >= (sizeof (line) - 1))) {
142 /*
143 * Catch long lines but not if this is a short
144 * line with no '\n' at the end of the input.
145 */
146 if (warning)
147 fprintf(stderr,
148 "%s: Warning: more than %d "
149 "bytes on line %d, ignored\n",
150 cmd, sizeof (line) - 2, lineno);
151 /*
152 * Discard the remaining lines until the
153 * newline or EOF.
154 */
155 while ((fgetsp = fgets(line, sizeof (line),
156 fp)) != NULL)
157 if (line[strlen(line) - 1] == '\n')
158 break;
159 if (fgetsp == NULL)
160 endoffile = 1;
161 continue;
162 }
163
164 if (sscanf(line, "%s", adr) != 1) { /* Blank line, ignore */
165 continue;
166 }
167
168 if ((trailer = strpbrk(line, " \t")) == NULL) {
169 if (warning)
170 fprintf(stderr,
171 "%s: Warning: no host names on line %d, "
172 "ignored\n", cmd, lineno);
173 continue;
174 }
175
176 /*
177 * check for valid addresses
178 *
179 * Attempt an ipv4 conversion, this accepts all valid
180 * ipv4 addresses including:
181 * d
182 * d.d
183 * d.d.d
184 * Unfortunately inet_pton() doesn't recognise these.
185 */
186
187 in.s_addr = inet_addr(adr);
188 if (-1 != (int)in.s_addr) {
189 /*
190 * It's safe not to check return of NULL as
191 * nadrp is checked for validity later.
192 */
193 nadrp = inet_ntop(AF_INET, &in, nadr, sizeof (nadr));
194 } else {
195 nadrp = NULL; /* Not a valid IPv4 address */
196 }
197
198 if (nadrp == NULL) {
199 if (inet_pton(AF_INET6, adr, &in6) == 1) {
200 nadrp = inet_ntop(AF_INET6, &in6,
201 nadr, sizeof (nadr));
202 }
203 if (nadrp == NULL) { /* Invalid IPv6 too */
204 if (warning)
205 fprintf(stderr,
206 "%s: Warning: malformed"
207 " address on"
208 " line %d, ignored\n",
209 cmd, lineno);
210 continue;
211 } else if (ipv4) {
212 continue; /* Ignore valid IPv6 */
213 }
214 }
215
216 verify_and_output(nadrp, trailer, lineno);
217
218 } /* while */
219 return (0);
220 /* NOTREACHED */
221 }
222
223 /*
224 * verify_and_output
225 *
226 * Builds and verifies the output key and value string
227 *
228 * It makes sure these rules are followed:
229 * key + separator + value <= OUTPUTSIZ (for ndbm)
230 * names <= MAXALIASES + 1, ie one canonical name + MAXALIASES aliases
231 * It will also ignore everything after a '#' comment character
232 */
233 static void
verify_and_output(const char * key,char * value,int lineno)234 verify_and_output(const char *key, char *value, int lineno)
235 {
236 char *p; /* General char pointer */
237 char *endp; /* Points to the NULL at the end */
238 char *namep; /* First character of a name */
239 char tmpbuf[OUTPUTSIZ+1]; /* Buffer before writing out */
240 char *tmpbufp = tmpbuf; /* Current point in output string */
241 int n = 0; /* Length of output */
242 int names = 0; /* Number of names found */
243 int namelen; /* Length of the name */
244
245 if (key) { /* Just in case key is NULL */
246 n = strlen(key);
247 if (n > OUTPUTSIZ) {
248 if (warning)
249 fprintf(stderr,
250 "%s: address too long on "
251 "line %d, line discarded\n",
252 cmd, lineno);
253 return;
254 }
255 memcpy(tmpbufp, key, n+1); /* Plus the '\0' */
256 tmpbufp += n;
257 }
258
259 if (value) { /* Just in case value is NULL */
260 p = value;
261 if ((endp = strchr(value, '#')) == 0) /* Ignore # comments */
262 endp = p + strlen(p); /* Or endp = EOL */
263 do {
264 /*
265 * Skip white space. Type conversion is
266 * necessary to avoid unfortunate effects of
267 * 8-bit characters appearing negative.
268 */
269 while ((p < endp) && isspace((unsigned char)*p))
270 p++;
271
272 if (p == endp) /* End of the string */
273 break;
274
275 names++;
276 if (names > (MAXALIASES+1)) { /* cname + MAXALIASES */
277 if (warning)
278 fprintf(stderr,
279 "%s: Warning: too many "
280 "host names on line %d, "
281 "truncating\n",
282 cmd, lineno);
283 break;
284 }
285
286 namep = p;
287 while ((p < endp) && !isspace((unsigned char)*p))
288 p++;
289
290 namelen = p - namep;
291 n += namelen + 1; /* single white space + name */
292 *p = '\0'; /* Terminate the name string */
293 if (n > OUTPUTSIZ) {
294 if (warning)
295 fprintf(stderr,
296 "%s: Warning: %d byte ndbm limit "
297 "reached on line %d, truncating\n",
298 cmd, OUTPUTSIZ, lineno);
299 break;
300 }
301
302 if (names == 1) /* First space is a '\t' */
303 *tmpbufp++ = '\t';
304 else
305 *tmpbufp++ = ' ';
306
307 memcpy(tmpbufp, namep, namelen+1); /* Plus the '\0' */
308 tmpbufp += namelen;
309
310 if (p < endp)
311 p++; /* Skip the added NULL */
312
313 } while (p < endp);
314 }
315
316 if (names > 0) {
317 fputs(tmpbuf, stdout);
318 fputc('\n', stdout);
319 } else {
320 if (warning)
321 fprintf(stderr,
322 "%s: Warning: no host names on line %d, "
323 "ignored\n", cmd, lineno);
324 }
325 }
326