summaryrefslogtreecommitdiff
path: root/ares__get_hostent.c
blob: 4497d60d0d9f0af3bf25a103197e1bce0958691d (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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261

/* Copyright 1998, 2011 by the Massachusetts Institute of Technology.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting
 * documentation, and that the name of M.I.T. not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 */

#include "ares_setup.h"

#ifdef HAVE_NETINET_IN_H
#  include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#  include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#  include <arpa/inet.h>
#endif

#include "ares.h"
#include "ares_inet_net_pton.h"
#include "ares_nowarn.h"
#include "ares_private.h"

int ares__get_hostent(FILE *fp, int family, struct hostent **host)
{
  char *line = NULL, *p, *q, **alias;
  char *txtaddr, *txthost, *txtalias;
  int status;
  size_t addrlen, linesize, naliases;
  struct ares_addr addr;
  struct hostent *hostent = NULL;

  *host = NULL; /* Assume failure */

  /* Validate family */
  switch (family) {
    case AF_INET:
    case AF_INET6:
    case AF_UNSPEC:
      break;
    default:
      return ARES_EBADFAMILY;
  }

  while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
    {

      /* Trim line comment. */
      p = line;
      while (*p && (*p != '#'))
        p++;
      *p = '\0';

      /* Trim trailing whitespace. */
      q = p - 1;
      while ((q >= line) && ISSPACE(*q))
        q--;
      *++q = '\0';

      /* Skip leading whitespace. */
      p = line;
      while (*p && ISSPACE(*p))
        p++;
      if (!*p)
        /* Ignore line if empty. */
        continue;

      /* Pointer to start of IPv4 or IPv6 address part. */
      txtaddr = p;

      /* Advance past address part. */
      while (*p && !ISSPACE(*p))
        p++;
      if (!*p)
        /* Ignore line if reached end of line. */
        continue;

      /* Null terminate address part. */
      *p = '\0';

      /* Advance to host name */
      p++;
      while (*p && ISSPACE(*p))
        p++;
      if (!*p)
        /* Ignore line if reached end of line. */
        continue;

      /* Pointer to start of host name. */
      txthost = p;

      /* Advance past host name. */
      while (*p && !ISSPACE(*p))
        p++;

      /* Pointer to start of first alias. */
      txtalias = NULL;
      if (*p)
        {
          q = p + 1;
          while (*q && ISSPACE(*q))
            q++;
          if (*q)
            txtalias = q;
        }

      /* Null terminate host name. */
      *p = '\0';

      /* find out number of aliases. */
      naliases = 0;
      if (txtalias)
        {
          p = txtalias;
          while (*p)
            {
              while (*p && !ISSPACE(*p))
                p++;
              while (*p && ISSPACE(*p))
                p++;
              naliases++;
            }
        }

      /* Convert address string to network address for the requested family. */
      addrlen = 0;
      addr.family = AF_UNSPEC;
      addr.addrV4.s_addr = INADDR_NONE;
      if ((family == AF_INET) || (family == AF_UNSPEC))
        {
          addr.addrV4.s_addr = inet_addr(txtaddr);
          if (addr.addrV4.s_addr != INADDR_NONE)
            {
              /* Actual network address family and length. */
              addr.family = AF_INET;
              addrlen = sizeof(addr.addrV4);
            }
        }
      if ((family == AF_INET6) || ((family == AF_UNSPEC) && (!addrlen)))
        {
          if (ares_inet_pton(AF_INET6, txtaddr, &addr.addrV6) > 0)
            {
              /* Actual network address family and length. */
              addr.family = AF_INET6;
              addrlen = sizeof(addr.addrV6);
            }
        }
      if (!addrlen)
        /* Ignore line if invalid address string for the requested family. */
        continue;

      /*
      ** Actual address family possible values are AF_INET and AF_INET6 only.
      */

      /* Allocate memory for the hostent structure. */
      hostent = malloc(sizeof(struct hostent));
      if (!hostent)
        break;

      /* Initialize fields for out of memory condition. */
      hostent->h_aliases = NULL;
      hostent->h_addr_list = NULL;

      /* Copy official host name. */
      hostent->h_name = strdup(txthost);
      if (!hostent->h_name)
        break;

      /* Copy network address. */
      hostent->h_addr_list = malloc(2 * sizeof(char *));
      if (!hostent->h_addr_list)
        break;
      hostent->h_addr_list[1] = NULL;
      hostent->h_addr_list[0] = malloc(addrlen);
      if (!hostent->h_addr_list[0])
        break;
      if (addr.family == AF_INET)
        memcpy(hostent->h_addr_list[0], &addr.addrV4, sizeof(addr.addrV4));
      else
        memcpy(hostent->h_addr_list[0], &addr.addrV6, sizeof(addr.addrV6));

      /* Copy aliases. */
      hostent->h_aliases = malloc((naliases + 1) * sizeof(char *));
      if (!hostent->h_aliases)
        break;
      alias = hostent->h_aliases;
      while (naliases)
        *(alias + naliases--) = NULL;
      *alias = NULL;
      while (txtalias)
        {
          p = txtalias;
          while (*p && !ISSPACE(*p))
            p++;
          q = p;
          while (*q && ISSPACE(*q))
            q++;
          *p = '\0';
          if ((*alias = strdup(txtalias)) == NULL)
            break;
          alias++;
          txtalias = *q ? q : NULL;
        }
      if (txtalias)
        /* Alias memory allocation failure. */
        break;

      /* Copy actual network address family and length. */
      hostent->h_addrtype = aresx_sitoss(addr.family);
      hostent->h_length = aresx_uztoss(addrlen);

      /* Free line buffer. */
      free(line);

      /* Return hostent successfully */
      *host = hostent;
      return ARES_SUCCESS;

    }

  /* If allocated, free line buffer. */
  if (line)
    free(line);

  if (status == ARES_SUCCESS)
    {
      /* Memory allocation failure; clean up. */
      if (hostent)
        {
          if (hostent->h_name)
            free((char *) hostent->h_name);
          if (hostent->h_aliases)
            {
              for (alias = hostent->h_aliases; *alias; alias++)
                free(*alias);
              free(hostent->h_aliases);
            }
          if (hostent->h_addr_list)
            {
              if (hostent->h_addr_list[0])
                free(hostent->h_addr_list[0]);
              free(hostent->h_addr_list);
            }
          free(hostent);
        }
      return ARES_ENOMEM;
    }

  return status;
}