aboutsummaryrefslogtreecommitdiff
path: root/resolv/ns_name_ntop.c
blob: 4dab3a3ce0286891d87dbfdaad1dc5c937ad2986 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
/* Convert DNS domain names from network format to textual presentation format.
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <arpa/nameser.h>
#include <errno.h>
#include <shlib-compat.h>
#include <stdbool.h>

/* Thinking in noninternationalized US-ASCII (per the DNS spec), is
   this character special ("in need of quoting")?  */
static inline bool
special (int ch)
{
  switch (ch)
    {
    case '"':
    case '.':
    case ';':
    case '\\':
    case '(':
    case ')':
      /* Special modifiers in zone files.  */
    case '@':
    case '$':
      return true;
    default:
      return false;
    }
}

/* Thinking in noninternationalized US-ASCII (per the DNS spec), is
   this character visible and not a space when printed?  */
static inline bool
printable (int ch)
{
  return ch > 0x20 && ch < 0x7f;
}

/* Converts an uncompressed, encoded domain name to printable ASCII as
   per RFC1035.  Returns the number of bytes written to buffer, or -1
   (with errno set).  The root is returned as "."  All other domains
   are returned in non absolute form.  */
int
___ns_name_ntop (const unsigned char *src, char *dst, size_t dstsiz)
{
  const unsigned char *cp;
  char *dn, *eom;
  unsigned char c;
  int l;

  cp = src;
  dn = dst;
  eom = dst + dstsiz;

  while ((l = *cp++) != 0)
    {
      if (l >= 64)
        {
          /* Some kind of compression pointer.  */
          __set_errno (EMSGSIZE);
          return -1;
        }
      if (dn != dst)
        {
          if (dn >= eom)
            {
              __set_errno (EMSGSIZE);
              return -1;
            }
          *dn++ = '.';
        }
      for (; l > 0; l--)
        {
          c = *cp++;
          if (special (c))
            {
              if (eom - dn < 2)
                {
                  __set_errno (EMSGSIZE);
                  return -1;
                }
              *dn++ = '\\';
              *dn++ = c;
            }
          else if (!printable (c))
            {
              if (eom - dn < 4)
                {
                  __set_errno (EMSGSIZE);
                  return -1;
                }
              *dn++ = '\\';
              *dn++ = '0' + (c / 100);
              *dn++ = '0' + ((c % 100) / 10);
              *dn++ = '0' + (c % 10);
            }
          else
            {
              if (eom - dn < 2)
                {
                  __set_errno (EMSGSIZE);
                  return -1;
                }
              *dn++ = c;
            }
        }
    }
  if (dn == dst)
    {
      if (dn >= eom)
        {
          __set_errno (EMSGSIZE);
          return -1;
        }
      *dn++ = '.';
    }
  if (dn >= eom)
    {
      __set_errno (EMSGSIZE);
      return -1;
    }
  *dn++ = '\0';
  return dn - dst;
}
versioned_symbol (libc, ___ns_name_ntop, ns_name_ntop, GLIBC_2_34);
versioned_symbol (libc, ___ns_name_ntop, __ns_name_ntop, GLIBC_PRIVATE);
libc_hidden_ver (___ns_name_ntop, __ns_name_ntop)

#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_9, GLIBC_2_34)
compat_symbol (libresolv, ___ns_name_ntop, ns_name_ntop, GLIBC_2_9);
#endif