summaryrefslogtreecommitdiff
path: root/ares__get_hostent.c
blob: 0b043423e97dda10ca8d1067827b9e407ad553ad (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
/* Copyright 1998 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 "setup.h"
#include <sys/types.h>

#if !defined(WIN32) || defined(WATT32)
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "ares.h"
#include "ares_private.h"

int ares__get_hostent(FILE *fp, struct hostent **host)
{
  char *line = NULL, *p, *q, *canonical, **alias;
  int status, linesize, end_at_hostname, naliases;
  struct in_addr addr;
  struct hostent *hostent = NULL;

  while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
    {
      /* Skip comment lines; terminate line at comment character. */
      if (*line == '#' || !*line)
        continue;
      p = strchr(line, '#');
      if (p)
        *p = 0;

      /* Get the address part. */
      p = line;
      while (*p && !isspace((unsigned char)*p))
        p++;
      if (!*p)
        continue;
      *p = 0;
      addr.s_addr = inet_addr(line);
      if (addr.s_addr == INADDR_NONE)
        continue;

      /* Get the canonical hostname. */
      p++;
      while (isspace((unsigned char)*p))
        p++;
      if (!*p)
        continue;
      q = p;
      while (*q && !isspace((unsigned char)*q))
        q++;
      end_at_hostname = (*q == 0);
      *q = 0;
      canonical = p;

      naliases = 0;
      if (!end_at_hostname)
        {
          /* Count the aliases. */
          p = q + 1;
          while (isspace((unsigned char)*p))
            p++;
          while (*p)
            {
              while (*p && !isspace((unsigned char)*p))
                p++;
              while (isspace((unsigned char)*p))
                p++;
              naliases++;
            }
        }

      /* Allocate memory for the host structure. */
      hostent = malloc(sizeof(struct hostent));
      if (!hostent)
        break;
      hostent->h_aliases = NULL;
      hostent->h_addr_list = NULL;
      hostent->h_name = strdup(canonical);
      if (!hostent->h_name)
        break;
      hostent->h_addr_list = malloc(2 * sizeof(char *));
      if (!hostent->h_addr_list)
        break;
      hostent->h_addr_list[0] = malloc(sizeof(struct in_addr));
      if (!hostent->h_addr_list[0])
        break;
      hostent->h_aliases = malloc((naliases + 1) * sizeof(char *));
      if (!hostent->h_aliases)
        break;

      /* Copy in aliases. */
      naliases = 0;
      if (!end_at_hostname)
        {
          p = canonical + strlen(canonical) + 1;
          while (isspace((unsigned char)*p))
            p++;
          while (*p)
            {
              q = p;
              while (*q && !isspace((unsigned char)*q))
                q++;
              hostent->h_aliases[naliases] = malloc(q - p + 1);
              if (hostent->h_aliases[naliases] == NULL)
                break;
              memcpy(hostent->h_aliases[naliases], p, q - p);
              hostent->h_aliases[naliases][q - p] = 0;
              p = q;
              while (isspace((unsigned char)*p))
                p++;
              naliases++;
            }
          if (*p)
            break;
        }
      hostent->h_aliases[naliases] = NULL;

      hostent->h_addrtype = AF_INET;
      hostent->h_length = sizeof(struct in_addr);
      memcpy(hostent->h_addr_list[0], &addr, sizeof(struct in_addr));
      hostent->h_addr_list[1] = NULL;
      *host = hostent;
      free(line);
      return ARES_SUCCESS;
    }
  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);
            }
          if(hostent->h_aliases)
            free(hostent->h_aliases);
          if (hostent->h_addr_list && hostent->h_addr_list[0])
            free(hostent->h_addr_list[0]);
          if(hostent->h_addr_list)
            free(hostent->h_addr_list);
          free(hostent);
        }
      return ARES_ENOMEM;
    }

  return status;
}