File: nscd_getgr_r.c

package info (click to toggle)
glibc 2.19-18+deb8u4
  • links: PTS, VCS
  • area: main
  • in suites: jessie-backports
  • size: 204,416 kB
  • ctags: 144,800
  • sloc: ansic: 970,361; asm: 241,207; sh: 10,069; makefile: 8,475; cpp: 3,595; perl: 2,077; pascal: 1,839; awk: 1,704; yacc: 317; sed: 73
file content (330 lines) | stat: -rw-r--r-- 9,422 bytes parent folder | download | duplicates (10)
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
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
/* Copyright (C) 1998-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 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, see
   <http://www.gnu.org/licenses/>.  */

#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <grp.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <not-cancel.h>
#include <_itoa.h>

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

int __nss_not_use_nscd_group;

static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
			 struct group *resultbuf, char *buffer,
			 size_t buflen, struct group **result)
     internal_function;


int
__nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
		   size_t buflen, struct group **result)
{
  return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
		       buffer, buflen, result);
}


int
__nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
		   size_t buflen, struct group **result)
{
  char buf[3 * sizeof (gid_t)];
  buf[sizeof (buf) - 1] = '\0';
  char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);

  return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
		       buffer, buflen, result);
}


libc_locked_map_ptr (,__gr_map_handle) attribute_hidden;
/* Note that we only free the structure if necessary.  The memory
   mapping is not removed since it is not visible to the malloc
   handling.  */
libc_freeres_fn (gr_map_free)
{
  if (__gr_map_handle.mapped != NO_MAPPING)
    {
      void *p = __gr_map_handle.mapped;
      __gr_map_handle.mapped = NO_MAPPING;
      free (p);
    }
}


static int
internal_function
nscd_getgr_r (const char *key, size_t keylen, request_type type,
	      struct group *resultbuf, char *buffer, size_t buflen,
	      struct group **result)
{
  int gc_cycle;
  int nretries = 0;
  const uint32_t *len = NULL;
  size_t lensize = 0;

  /* If the mapping is available, try to search there instead of
     communicating with the nscd.  */
  struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
						       &__gr_map_handle,
						       &gc_cycle);
 retry:;
  const char *gr_name = NULL;
  size_t gr_name_len = 0;
  int retval = -1;
  const char *recend = (const char *) ~UINTMAX_C (0);
  gr_response_header gr_resp;

  if (mapped != NO_MAPPING)
    {
      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
						    sizeof gr_resp);
      if (found != NULL)
	{
	  len = (const uint32_t *) (&found->data[0].grdata + 1);
	  gr_resp = found->data[0].grdata;
	  gr_name = ((const char *) len
		     + gr_resp.gr_mem_cnt * sizeof (uint32_t));
	  gr_name_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
	  recend = (const char *) found->data + found->recsize;
	  /* Now check if we can trust gr_resp fields.  If GC is
	     in progress, it can contain anything.  */
	  if (mapped->head->gc_cycle != gc_cycle)
	    {
	      retval = -2;
	      goto out;
	    }

	  /* The alignment is always sufficient, unless GC is in progress.  */
	  assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
	}
    }

  int sock = -1;
  if (gr_name == NULL)
    {
      sock = __nscd_open_socket (key, keylen, type, &gr_resp,
				 sizeof (gr_resp));
      if (sock == -1)
	{
	  __nss_not_use_nscd_group = 1;
	  goto out;
	}
    }

  /* No value found so far.  */
  *result = NULL;

  if (__builtin_expect (gr_resp.found == -1, 0))
    {
      /* The daemon does not cache this database.  */
      __nss_not_use_nscd_group = 1;
      goto out_close;
    }

  if (gr_resp.found == 1)
    {
      struct iovec vec[2];
      char *p = buffer;
      size_t total_len;
      uintptr_t align;
      nscd_ssize_t cnt;

      /* Now allocate the buffer the array for the group members.  We must
	 align the pointer.  */
      align = ((__alignof__ (char *) - (p - ((char *) 0)))
	       & (__alignof__ (char *) - 1));
      total_len = (align + (1 + gr_resp.gr_mem_cnt) * sizeof (char *)
		   + gr_resp.gr_name_len + gr_resp.gr_passwd_len);
      if (__builtin_expect (buflen < total_len, 0))
	{
	no_room:
	  __set_errno (ERANGE);
	  retval = ERANGE;
	  goto out_close;
	}
      buflen -= total_len;

      p += align;
      resultbuf->gr_mem = (char **) p;
      p += (1 + gr_resp.gr_mem_cnt) * sizeof (char *);

      /* Set pointers for strings.  */
      resultbuf->gr_name = p;
      p += gr_resp.gr_name_len;
      resultbuf->gr_passwd = p;
      p += gr_resp.gr_passwd_len;

      /* Fill in what we know now.  */
      resultbuf->gr_gid = gr_resp.gr_gid;

      /* Read the length information, group name, and password.  */
      if (gr_name == NULL)
	{
	  /* Handle a simple, usual case: no group members.  */
	  if (__builtin_expect (gr_resp.gr_mem_cnt == 0, 1))
	    {
	      size_t n = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
	      if (__builtin_expect (__readall (sock, resultbuf->gr_name, n)
				    != (ssize_t) n, 0))
		goto out_close;
	    }
	  else
	    {
	      /* Allocate array to store lengths.  */
	      if (lensize == 0)
		{
		  lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t);
		  len = (uint32_t *) alloca (lensize);
		}
	      else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize)
		len = extend_alloca (len, lensize,
				     gr_resp.gr_mem_cnt * sizeof (uint32_t));

	      vec[0].iov_base = (void *) len;
	      vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
	      vec[1].iov_base = resultbuf->gr_name;
	      vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
	      total_len = vec[0].iov_len + vec[1].iov_len;

	      /* Get this data.  */
	      size_t n = __readvall (sock, vec, 2);
	      if (__builtin_expect (n != total_len, 0))
		goto out_close;
	    }
	}
      else
	/* We already have the data.  Just copy the group name and
	   password.  */
	memcpy (resultbuf->gr_name, gr_name,
		gr_resp.gr_name_len + gr_resp.gr_passwd_len);

      /* Clear the terminating entry.  */
      resultbuf->gr_mem[gr_resp.gr_mem_cnt] = NULL;

      /* Prepare reading the group members.  */
      total_len = 0;
      for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
	{
	  resultbuf->gr_mem[cnt] = p;
	  total_len += len[cnt];
	  p += len[cnt];
	}

      if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
	{
	  /* len array might contain garbage during nscd GC cycle,
	     retry rather than fail in that case.  */
	  if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
	    retval = -2;
	  goto out_close;
	}
      if (__builtin_expect (total_len > buflen, 0))
	{
	  /* len array might contain garbage during nscd GC cycle,
	     retry rather than fail in that case.  */
	  if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
	    {
	      retval = -2;
	      goto out_close;
	    }
	  else
	    goto no_room;
	}

      retval = 0;

      /* If there are no group members TOTAL_LEN is zero.  */
      if (gr_name == NULL)
	{
	  if (total_len > 0
	      && __builtin_expect (__readall (sock, resultbuf->gr_mem[0],
					      total_len) != total_len, 0))
	    {
	      /* The `errno' to some value != ERANGE.  */
	      __set_errno (ENOENT);
	      retval = ENOENT;
	    }
	  else
	    *result = resultbuf;
	}
      else
	{
	  /* Copy the group member names.  */
	  memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);

	  /* Try to detect corrupt databases.  */
	  if (resultbuf->gr_name[gr_name_len - 1] != '\0'
	      || resultbuf->gr_passwd[gr_resp.gr_passwd_len - 1] != '\0'
	      || ({for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
		    if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
		      break;
		  cnt < gr_resp.gr_mem_cnt; }))
	    {
	      /* We cannot use the database.  */
	      retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
	      goto out_close;
	    }

	  *result = resultbuf;
	}
    }
  else
    {
      /* Set errno to 0 to indicate no error, just no found record.  */
      __set_errno (0);
      /* Even though we have not found anything, the result is zero.  */
      retval = 0;
    }

 out_close:
  if (sock != -1)
    close_not_cancel_no_status (sock);
 out:
  if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
    {
      /* When we come here this means there has been a GC cycle while we
	 were looking for the data.  This means the data might have been
	 inconsistent.  Retry if possible.  */
      if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
	{
	  /* nscd is just running gc now.  Disable using the mapping.  */
	  if (atomic_decrement_val (&mapped->counter) == 0)
	    __nscd_unmap (mapped);
	  mapped = NO_MAPPING;
	}

      if (retval != -1)
	goto retry;
    }

  return retval;
}