nscd/nscd_getgr_r.c

   1 /* Copyright (C) 1998-2000, 2002-2005, 2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <alloca.h>
  21 #include <assert.h>
  22 #include <errno.h>
  23 #include <grp.h>
  24 #include <stdint.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <sys/mman.h>
  30 #include <sys/socket.h>
  31 #include <sys/uio.h>
  32 #include <sys/un.h>
  33 #include <not-cancel.h>
  34 #include <stdio-common/_itoa.h>
  35
  36 #include "nscd-client.h"
  37 #include "nscd_proto.h"
  38
  39 int __nss_not_use_nscd_group;
  40
  41 static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
  42                          struct group *resultbuf, char *buffer,
  43                          size_t buflen, struct group **result)
  44      internal_function;
  45
  46
  47 int
  48 __nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
  49                    size_t buflen, struct group **result)
  50 {
  51   return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
  52                        buffer, buflen, result);
  53 }
  54
  55
  56 int
  57 __nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
  58                    size_t buflen, struct group **result)
  59 {
  60   char buf[3 * sizeof (gid_t)];
  61   buf[sizeof (buf) - 1] = '\0';
  62   char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);
  63
  64   return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
  65                        buffer, buflen, result);
  66 }
  67
  68
  69 libc_locked_map_ptr (,__gr_map_handle) attribute_hidden;
  70 /* Note that we only free the structure if necessary.  The memory
  71    mapping is not removed since it is not visible to the malloc
  72    handling.  */
  73 libc_freeres_fn (gr_map_free)
  74 {
  75   if (__gr_map_handle.mapped != NO_MAPPING)
  76     {
  77       void *p = __gr_map_handle.mapped;
  78       __gr_map_handle.mapped = NO_MAPPING;
  79       free (p);
  80     }
  81 }
  82
  83
  84 static int
  85 internal_function
  86 nscd_getgr_r (const char *key, size_t keylen, request_type type,
  87               struct group *resultbuf, char *buffer, size_t buflen,
  88               struct group **result)
  89 {
  90   int gc_cycle;
  91   const uint32_t *len = NULL;
  92   size_t lensize = 0;
  93
  94   /* If the mapping is available, try to search there instead of
  95      communicating with the nscd.  */
  96   struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
  97                                                        &__gr_map_handle,
  98                                                        &gc_cycle);
  99  retry:;
 100   const gr_response_header *gr_resp = NULL;
 101   const char *gr_name = NULL;
 102   size_t gr_name_len = 0;
 103   int retval = -1;
 104   const char *recend = (const char *) ~UINTMAX_C (0);
 105
 106   if (mapped != NO_MAPPING)
 107     {
 108       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 109                                                           mapped);
 110       if (found != NULL)
 111         {
 112           gr_resp = &found->data[0].grdata;
 113           len = (const uint32_t *) (gr_resp + 1);
 114           /* The alignment is always sufficient.  */
 115           assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
 116           gr_name = ((const char *) len
 117                      + gr_resp->gr_mem_cnt * sizeof (uint32_t));
 118           gr_name_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 119           recend = (const char *) found->data + found->recsize;
 120         }
 121     }
 122
 123   gr_response_header gr_resp_mem;
 124   int sock = -1;
 125   if (gr_resp == NULL)
 126     {
 127       sock = __nscd_open_socket (key, keylen, type, &gr_resp_mem,
 128                                  sizeof (gr_resp_mem));
 129       if (sock == -1)
 130         {
 131           __nss_not_use_nscd_group = 1;
 132           goto out;
 133         }
 134
 135       gr_resp = &gr_resp_mem;
 136     }
 137
 138   /* No value found so far.  */
 139   *result = NULL;
 140
 141   if (__builtin_expect (gr_resp->found == -1, 0))
 142     {
 143       /* The daemon does not cache this database.  */
 144       __nss_not_use_nscd_group = 1;
 145       goto out_close;
 146     }
 147
 148   if (gr_resp->found == 1)
 149     {
 150       struct iovec vec[2];
 151       char *p = buffer;
 152       size_t total_len;
 153       uintptr_t align;
 154       nscd_ssize_t cnt;
 155
 156       /* Now allocate the buffer the array for the group members.  We must
 157          align the pointer.  */
 158       align = ((__alignof__ (char *) - (p - ((char *) 0)))
 159                & (__alignof__ (char *) - 1));
 160       total_len = (align + (1 + gr_resp->gr_mem_cnt) * sizeof (char *)
 161                    + gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 162       if (__builtin_expect (buflen < total_len, 0))
 163         {
 164         no_room:
 165           __set_errno (ERANGE);
 166           retval = ERANGE;
 167           goto out_close;
 168         }
 169       buflen -= total_len;
 170
 171       p += align;
 172       resultbuf->gr_mem = (char **) p;
 173       p += (1 + gr_resp->gr_mem_cnt) * sizeof (char *);
 174
 175       /* Set pointers for strings.  */
 176       resultbuf->gr_name = p;
 177       p += gr_resp->gr_name_len;
 178       resultbuf->gr_passwd = p;
 179       p += gr_resp->gr_passwd_len;
 180
 181       /* Fill in what we know now.  */
 182       resultbuf->gr_gid = gr_resp->gr_gid;
 183
 184       /* Read the length information, group name, and password.  */
 185       if (gr_name == NULL)
 186         {
 187           /* Allocate array to store lengths.  */
 188           if (lensize == 0)
 189             {
 190               lensize = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 191               len = (uint32_t *) alloca (lensize);
 192             }
 193           else if (gr_resp->gr_mem_cnt * sizeof (uint32_t) > lensize)
 194             len = extend_alloca (len, lensize,
 195                                  gr_resp->gr_mem_cnt * sizeof (uint32_t));
 196
 197           vec[0].iov_base = (void *) len;
 198           vec[0].iov_len = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 199           vec[1].iov_base = resultbuf->gr_name;
 200           vec[1].iov_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 201           total_len = vec[0].iov_len + vec[1].iov_len;
 202
 203           /* Get this data.  */
 204           size_t n = __readvall (sock, vec, 2);
 205           if (__builtin_expect (n != total_len, 0))
 206             goto out_close;
 207         }
 208       else
 209         /* We already have the data.  Just copy the group name and
 210            password.  */
 211         memcpy (resultbuf->gr_name, gr_name,
 212                 gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 213
 214       /* Clear the terminating entry.  */
 215       resultbuf->gr_mem[gr_resp->gr_mem_cnt] = NULL;
 216
 217       /* Prepare reading the group members.  */
 218       total_len = 0;
 219       for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 220         {
 221           resultbuf->gr_mem[cnt] = p;
 222           total_len += len[cnt];
 223           p += len[cnt];
 224         }
 225
 226       if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
 227         goto out_close;
 228       if (__builtin_expect (total_len > buflen, 0))
 229         goto no_room;
 230
 231       retval = 0;
 232       if (gr_name == NULL)
 233         {
 234           size_t n = __readall (sock, resultbuf->gr_mem[0], total_len);
 235           if (__builtin_expect (n != total_len, 0))
 236             {
 237               /* The `errno' to some value != ERANGE.  */
 238               __set_errno (ENOENT);
 239               retval = ENOENT;
 240             }
 241           else
 242             *result = resultbuf;
 243         }
 244       else
 245         {
 246           /* Copy the group member names.  */
 247           memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
 248
 249           /* Try to detect corrupt databases.  */
 250           if (resultbuf->gr_name[gr_name_len - 1] != '\0'
 251               || resultbuf->gr_passwd[gr_resp->gr_passwd_len - 1] != '\0'
 252               || ({for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 253                      if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
 254                        break;
 255                    cnt < gr_resp->gr_mem_cnt; }))
 256             {
 257               /* We cannot use the database.  */
 258               retval = -1;
 259               goto out_close;
 260             }
 261
 262           *result = resultbuf;
 263         }
 264     }
 265   else
 266     {
 267       /* The `errno' to some value != ERANGE.  */
 268       __set_errno (ENOENT);
 269       /* Even though we have not found anything, the result is zero.  */
 270       retval = 0;
 271     }
 272
 273  out_close:
 274   if (sock != -1)
 275     close_not_cancel_no_status (sock);
 276  out:
 277   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
 278     {
 279       /* When we come here this means there has been a GC cycle while we
 280          were looking for the data.  This means the data might have been
 281          inconsistent.  Retry if possible.  */
 282       if ((gc_cycle & 1) != 0)
 283         {
 284           /* nscd is just running gc now.  Disable using the mapping.  */
 285           __nscd_unmap (mapped);
 286           mapped = NO_MAPPING;
 287         }
 288
 289       goto retry;
 290     }
 291
 292   return retval;
 293 }