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
23 #include "ares_nameser.h"
24
25 #include "ares.h"
26 #include "ares_private.h" /* for the memdebug */
27
28 /* Simply decodes a length-encoded character string. The first byte of the
29 * input is the length of the string to be returned and the bytes thereafter
30 * are the characters of the string. The returned result will be NULL
31 * terminated.
32 */
ares_expand_string(const unsigned char * encoded,const unsigned char * abuf,int alen,unsigned char ** s,long * enclen)33 int ares_expand_string(const unsigned char *encoded,
34 const unsigned char *abuf,
35 int alen,
36 unsigned char **s,
37 long *enclen)
38 {
39 unsigned char *q;
40 union {
41 ares_ssize_t sig;
42 size_t uns;
43 } elen;
44
45 if (encoded == abuf+alen)
46 return ARES_EBADSTR;
47
48 elen.uns = *encoded;
49 if (encoded+elen.sig+1 > abuf+alen)
50 return ARES_EBADSTR;
51
52 encoded++;
53
54 *s = ares_malloc(elen.uns+1);
55 if (*s == NULL)
56 return ARES_ENOMEM;
57 q = *s;
58 strncpy((char *)q, (char *)encoded, elen.uns);
59 q[elen.uns] = '\0';
60
61 *s = q;
62
63 *enclen = (long)(elen.sig+1);
64
65 return ARES_SUCCESS;
66 }
67
68