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_SYS_SOCKET_H
20 # include <sys/socket.h>
21 #endif
22 #ifdef HAVE_NETINET_IN_H
23 # include <netinet/in.h>
24 #endif
25 #ifdef HAVE_ARPA_NAMESER_H
26 # include <arpa/nameser.h>
27 #else
28 # include "nameser.h"
29 #endif
30
31 #include <string.h>
32 #include <stdlib.h>
33 #include "ares.h"
34 #include "ares_private.h" /* for the memdebug */
35
36 /* Simply decodes a length-encoded character string. The first byte of the
37 * input is the length of the string to be returned and the bytes thereafter
38 * are the characters of the string. The returned result will be NULL
39 * terminated.
40 */
ares_expand_string(const unsigned char * encoded,const unsigned char * abuf,int alen,unsigned char ** s,long * enclen)41 int ares_expand_string(const unsigned char *encoded,
42 const unsigned char *abuf,
43 int alen,
44 unsigned char **s,
45 long *enclen)
46 {
47 unsigned char *q;
48 union {
49 ssize_t sig;
50 size_t uns;
51 } elen;
52
53 if (encoded == abuf+alen)
54 return ARES_EBADSTR;
55
56 elen.uns = *encoded;
57 if (encoded+elen.sig+1 > abuf+alen)
58 return ARES_EBADSTR;
59
60 encoded++;
61
62 *s = malloc(elen.uns+1);
63 if (*s == NULL)
64 return ARES_ENOMEM;
65 q = *s;
66 strncpy((char *)q, (char *)encoded, elen.uns);
67 q[elen.uns] = '\0';
68
69 *s = q;
70
71 *enclen = (long)(elen.sig+1);
72
73 return ARES_SUCCESS;
74 }
75
76