summary refs log tree commit diff
path: root/nscd/nscd_gethst_r.c
blob: 69e7990eacccd082eb30240c74c8d389382e3783 (plain) (blame)
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
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
/* Copyright (C) 1998-2002, 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <netdb.h>
#include <resolv.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/nameser.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>

#include "nscd-client.h"
#include "nscd_proto.h"

int __nss_not_use_nscd_hosts;

static int nscd_gethst_r (const char *key, size_t keylen, request_type type,
			  struct hostent *resultbuf, char *buffer,
			  size_t buflen, int *h_errnop) internal_function;


int
__nscd_gethostbyname_r (const char *name, struct hostent *resultbuf,
			char *buffer, size_t buflen, int *h_errnop)
{
  request_type reqtype;

  reqtype = (_res.options & RES_USE_INET6) ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;

  return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
			buffer, buflen, h_errnop);
}


int
__nscd_gethostbyname2_r (const char *name, int af, struct hostent *resultbuf,
			 char *buffer, size_t buflen, int *h_errnop)
{
  request_type reqtype;

  reqtype = af == AF_INET6 ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;

  return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
			buffer, buflen, h_errnop);
}


int
__nscd_gethostbyaddr_r (const void *addr, socklen_t len, int type,
			struct hostent *resultbuf, char *buffer, size_t buflen,
			int *h_errnop)
{
  request_type reqtype;

  if (!((len == INADDRSZ && type == AF_INET)
	|| (len == IN6ADDRSZ && type == AF_INET6)))
    /* LEN and TYPE do not match.  */
    return -1;

  reqtype = type == AF_INET6 ? GETHOSTBYADDRv6 : GETHOSTBYADDR;

  return nscd_gethst_r (addr, len, reqtype, resultbuf, buffer, buflen,
			h_errnop);
}


/* Create a socket connected to a name. */
int
__nscd_open_socket (void)
{
  struct sockaddr_un addr;
  int sock;
  int saved_errno = errno;

  sock = __socket (PF_UNIX, SOCK_STREAM, 0);
  if (sock < 0)
    {
      __set_errno (saved_errno);
      return -1;
    }

  addr.sun_family = AF_UNIX;
  strcpy (addr.sun_path, _PATH_NSCDSOCKET);
  if (__connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
    {
      __close (sock);
      __set_errno (saved_errno);
      return -1;
    }

  return sock;
}


static int
internal_function
nscd_gethst_r (const char *key, size_t keylen, request_type type,
	       struct hostent *resultbuf, char *buffer, size_t buflen,
	       int *h_errnop)
{
  int sock = __nscd_open_socket ();
  hst_response_header hst_resp;
  request_header req;
  ssize_t nbytes;
  struct iovec vec[4];
  int result = -1;

  if (sock == -1)
    {
      __nss_not_use_nscd_group = 1;
      return -1;
    }

  req.version = NSCD_VERSION;
  req.type = type;
  req.key_len = keylen;

  vec[0].iov_base = &req;
  vec[0].iov_len = sizeof (request_header);
  vec[1].iov_base = (void *) key;
  vec[1].iov_len = req.key_len;

  nbytes = TEMP_FAILURE_RETRY (__writev (sock, vec, 2));
  if ((size_t) nbytes != sizeof (request_header) + req.key_len)
    goto out;

  nbytes = TEMP_FAILURE_RETRY (__read (sock, &hst_resp,
				       sizeof (hst_response_header)));
  if (__builtin_expect (nbytes != sizeof (hst_response_header), 0))
    goto out;

  if (hst_resp.found == -1)
    {
      /* The daemon does not cache this database.  */
      __nss_not_use_nscd_hosts = 1;
      goto out;
    }

  if (hst_resp.found == 1)
    {
      uint32_t *aliases_len;
      char *cp = buffer;
      uintptr_t align1;
      uintptr_t align2;
      size_t total_len;
      ssize_t cnt;
      char *ignore;
      int n;

      /* A first check whether the buffer is sufficiently large is possible.  */
      /* Now allocate the buffer the array for the group members.  We must
	 align the pointer and the base of the h_addr_list pointers.  */
      align1 = ((__alignof__ (char *) - (cp - ((char *) 0)))
		& (__alignof__ (char *) - 1));
      align2 = ((__alignof__ (char *) - ((cp + align1 + hst_resp.h_name_len)
					 - ((char *) 0)))
		& (__alignof__ (char *) - 1));
      if (buflen < (align1 + hst_resp.h_name_len + align2
		    + ((hst_resp.h_aliases_cnt + hst_resp.h_addr_list_cnt + 2)
		       * sizeof (char *))
		    + hst_resp.h_addr_list_cnt * (type == AF_INET
						  ? INADDRSZ : IN6ADDRSZ)))
	{
	no_room:
	  __set_errno (ERANGE);
	  result = ERANGE;
	  goto out;
	}
      cp += align1;

      /* Prepare the result as far as we can.  */
      resultbuf->h_aliases = (char **) cp;
      cp += (hst_resp.h_aliases_cnt + 1) * sizeof (char *);
      resultbuf->h_addr_list = (char **) cp;
      cp += (hst_resp.h_addr_list_cnt + 1) * sizeof (char *);

      resultbuf->h_name = cp;
      cp += hst_resp.h_name_len + align2;
      vec[0].iov_base = resultbuf->h_name;
      vec[0].iov_len = hst_resp.h_name_len;

      aliases_len = alloca (hst_resp.h_aliases_cnt * sizeof (uint32_t));
      vec[1].iov_base = aliases_len;
      vec[1].iov_len = hst_resp.h_aliases_cnt * sizeof (uint32_t);

      total_len = (hst_resp.h_name_len
		   + hst_resp.h_aliases_cnt * sizeof (uint32_t));

      n = 2;
      if (type == GETHOSTBYADDR || type == GETHOSTBYNAME)
	{
	  vec[2].iov_base = cp;
	  vec[2].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;

	  for (cnt = 0; cnt < hst_resp.h_addr_list_cnt; ++cnt)
	    {
	      resultbuf->h_addr_list[cnt] = cp;
	      cp += INADDRSZ;
	    }

	  resultbuf->h_addrtype = AF_INET;
	  resultbuf->h_length = INADDRSZ;

	  total_len += hst_resp.h_addr_list_cnt * INADDRSZ;

	  n = 3;
	}
      else
	{
	  if (hst_resp.h_length == INADDRSZ)
	    {
	      ignore = alloca (hst_resp.h_addr_list_cnt * INADDRSZ);
	      vec[2].iov_base = ignore;
	      vec[2].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;

	      total_len += hst_resp.h_addr_list_cnt * INADDRSZ;

	      n = 3;
	    }

	  vec[n].iov_base = cp;
	  vec[n].iov_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;

	  for (cnt = 0; cnt < hst_resp.h_addr_list_cnt; ++cnt)
	    {
	      resultbuf->h_addr_list[cnt] = cp;
	      cp += IN6ADDRSZ;
	    }

	  resultbuf->h_addrtype = AF_INET6;
	  resultbuf->h_length = IN6ADDRSZ;

	  total_len += hst_resp.h_addr_list_cnt * IN6ADDRSZ;

	  ++n;
	}
      resultbuf->h_addr_list[cnt] = NULL;

      if ((size_t) TEMP_FAILURE_RETRY (__readv (sock, vec, n)) != total_len)
	goto out;

      /*  Now we also can read the aliases.  */
      total_len = 0;
      for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
	{
	  resultbuf->h_aliases[cnt] = cp;
	  cp += aliases_len[cnt];
	  total_len += aliases_len[cnt];
	}
      resultbuf->h_aliases[cnt] = NULL;

      /* See whether this would exceed the buffer capacity.  */
      if (cp > buffer + buflen)
	goto no_room;

      /* And finally read the aliases.  */
      if ((size_t) TEMP_FAILURE_RETRY (__read (sock, resultbuf->h_aliases[0],
					       total_len)) == total_len)
	result = 0;
    }
  else
    {
      /* Store the error number.  */
      *h_errnop = hst_resp.error;

      /* The `errno' to some value != ERANGE.  */
      __set_errno (ENOENT);
      result = ENOENT;
    }

 out:
  __close (sock);

  return result;
}