1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 *
4 * Permission to use, copy, modify, and distribute this
5 * software and its documentation for any purpose and without
6 * fee is hereby granted, provided that the above copyright
7 * notice appear in all copies and that both that copyright
8 * notice and this permission notice appear in supporting
9 * documentation, and that the name of M.I.T. not be used in
10 * advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission.
12 * M.I.T. makes no representations about the suitability of
13 * this software for any purpose. It is provided "as is"
14 * without express or implied warranty.
15 */
16
17 #include "ares_setup.h"
18
19 #ifdef HAVE_NETINET_IN_H
20 # include <netinet/in.h>
21 #endif
22 #ifdef HAVE_ARPA_NAMESER_H
23 # include <arpa/nameser.h>
24 #else
25 # include "nameser.h"
26 #endif
27
28 #include "ares.h"
29 #include "ares_private.h" /* for the memdebug */
30
31 /* Simply decodes a length-encoded character string. The first byte of the
32 * input is the length of the string to be returned and the bytes thereafter
33 * are the characters of the string. The returned result will be NULL
34 * terminated.
35 */
ares_expand_string(const unsigned char * encoded,const unsigned char * abuf,int alen,unsigned char ** s,long * enclen)36 int ares_expand_string(const unsigned char *encoded,
37 const unsigned char *abuf,
38 int alen,
39 unsigned char **s,
40 long *enclen)
41 {
42 unsigned char *q;
43 union {
44 ares_ssize_t sig;
45 size_t uns;
46 } elen;
47
48 if (encoded == abuf+alen)
49 return ARES_EBADSTR;
50
51 elen.uns = *encoded;
52 if (encoded+elen.sig+1 > abuf+alen)
53 return ARES_EBADSTR;
54
55 encoded++;
56
57 *s = ares_malloc(elen.uns+1);
58 if (*s == NULL)
59 return ARES_ENOMEM;
60 q = *s;
61 strncpy((char *)q, (char *)encoded, elen.uns);
62 q[elen.uns] = '\0';
63
64 *s = q;
65
66 *enclen = (long)(elen.sig+1);
67
68 return ARES_SUCCESS;
69 }
70
71