summaryrefslogtreecommitdiffstats
path: root/src/resolv/ares/ares_data.c
blob: 1cccaa55cea94d49c07436c343556a412842ac05 (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
/* $Id: ares_data.c,v 1.2 2009-11-20 09:06:33 yangtse Exp $ */

/* Copyright (C) 2009 by Daniel Stenberg
 *
 * 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 <stddef.h>
#include <stdlib.h>

#include "ares.h"
#include "ares_data.h"

/*
** ares_free_data() - c-ares external API function.
**
** This function must be used by the application to free data memory that
** has been internally allocated by some c-ares function and for which a
** pointer has already been returned to the calling application. The list
** of c-ares functions returning pointers that must be free'ed using this
** function is:
**
**   ares_parse_srv_reply()
**   ares_parse_txt_reply()
*/

void _ares_free_data(void *dataptr)
{
  struct ares_data *ptr;

  if (!dataptr)
    return;

  ptr = (void *)((char *)dataptr - offsetof(struct ares_data, data));

  if (ptr->mark != ARES_DATATYPE_MARK)
    return;

  switch (ptr->type)
    {
      case ARES_DATATYPE_SRV_REPLY:

        if (ptr->data.srv_reply.next)
          _ares_free_data(ptr->data.srv_reply.next);
        if (ptr->data.srv_reply.host)
          free(ptr->data.srv_reply.host);
        break;

      case ARES_DATATYPE_TXT_REPLY:

        if (ptr->data.txt_reply.next)
          _ares_free_data(ptr->data.txt_reply.next);
        if (ptr->data.txt_reply.txt)
          free(ptr->data.txt_reply.txt);
        break;

      default:
        return;
    }

  free(ptr);
}


/*
** ares_malloc_data() - c-ares internal helper function.
**
** This function allocates memory for a c-ares private ares_data struct
** for the specified ares_datatype, initializes c-ares private fields
** and zero initializes those which later might be used from the public
** API. It returns an interior pointer which can be passed by c-ares
** functions to the calling application, and that must be free'ed using
** c-ares external API function ares_free_data().
*/

void *_ares_malloc_data(ares_datatype type)
{
  struct ares_data *ptr;

  ptr = malloc(sizeof(struct ares_data));
  if (!ptr)
    return NULL;

  switch (type)
    {
      case ARES_DATATYPE_SRV_REPLY:
        ptr->data.srv_reply.next = NULL;
        ptr->data.srv_reply.host = NULL;
        ptr->data.srv_reply.priority = 0;
        ptr->data.srv_reply.weight = 0;
        ptr->data.srv_reply.port = 0;
        break;

      case ARES_DATATYPE_TXT_REPLY:
        ptr->data.txt_reply.next = NULL;
        ptr->data.txt_reply.txt = NULL;
        ptr->data.txt_reply.length  = 0;
        break;

      default:
        free(ptr);
        return NULL;
    }

  ptr->mark = ARES_DATATYPE_MARK;
  ptr->type = type;

  return &ptr->data;
}


/*
** ares_get_datatype() - c-ares internal helper function.
**
** This function returns the ares_datatype of the data stored in a
** private ares_data struct when given the public API pointer.
*/

ares_datatype ares_get_datatype(void * dataptr)
{
  struct ares_data *ptr;

  ptr = (void *)((char *)dataptr - offsetof(struct ares_data, data));

  if (ptr->mark == ARES_DATATYPE_MARK)
    return ptr->type;

  return ARES_DATATYPE_UNKNOWN;
}