nscd/nscd_netgroup.c

   1 /* Copyright (C) 2011 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
   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 <errno.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <not-cancel.h>
  25
  26 #include "nscd-client.h"
  27 #include "nscd_proto.h"
  28
  29 int __nss_not_use_nscd_netgroup;
  30
  31
  32 libc_locked_map_ptr (static, map_handle);
  33 /* Note that we only free the structure if necessary.  The memory
  34    mapping is not removed since it is not visible to the malloc
  35    handling.  */
  36 libc_freeres_fn (pw_map_free)
  37 {
  38   if (map_handle.mapped != NO_MAPPING)
  39     {
  40       void *p = map_handle.mapped;
  41       map_handle.mapped = NO_MAPPING;
  42       free (p);
  43     }
  44 }
  45
  46
  47 int
  48 __nscd_setnetgrent (const char *group, struct __netgrent *datap)
  49 {
  50   int gc_cycle;
  51   int nretries = 0;
  52   size_t group_len = strlen (group);
  53
  54   /* If the mapping is available, try to search there instead of
  55      communicating with the nscd.  */
  56   struct mapped_database *mapped;
  57   mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
  58
  59  retry:;
  60   char *respdata = NULL;
  61   int retval = -1;
  62   netgroup_response_header netgroup_resp;
  63
  64   if (mapped != NO_MAPPING)
  65     {
  66       struct datahead *found = __nscd_cache_search (GETNETGRENT, group,
  67                                                     group_len, mapped,
  68                                                     sizeof netgroup_resp);
  69       if (found != NULL)
  70         {
  71           respdata = (char *) (&found->data[0].netgroupdata + 1);
  72           netgroup_resp = found->data[0].netgroupdata;
  73           /* Now check if we can trust pw_resp fields.  If GC is
  74              in progress, it can contain anything.  */
  75           if (mapped->head->gc_cycle != gc_cycle)
  76             {
  77               retval = -2;
  78               goto out;
  79             }
  80         }
  81     }
  82
  83   int sock = -1;
  84   if (respdata == NULL)
  85     {
  86       sock = __nscd_open_socket (group, group_len, GETNETGRENT,
  87                                  &netgroup_resp, sizeof (netgroup_resp));
  88       if (sock == -1)
  89         {
  90           /* nscd not running or wrong version.  */
  91           __nss_not_use_nscd_netgroup = 1;
  92           goto out;
  93         }
  94     }
  95
  96   if (netgroup_resp.found == 1)
  97     {
  98       size_t datalen = netgroup_resp.result_len;
  99
 100       /* If we do not have to read the data here it comes from the
 101          mapped data and does not have to be freed.  */
 102       if (respdata == NULL)
 103         {
 104           /* The data will come via the socket.  */
 105           respdata = malloc (datalen);
 106           if (respdata == NULL)
 107             goto out_close;
 108
 109           if ((size_t) __readall (sock, respdata, datalen) != datalen)
 110             {
 111               free (respdata);
 112               goto out_close;
 113             }
 114         }
 115
 116       datap->data = respdata;
 117       datap->data_size = datalen;
 118       datap->cursor = respdata;
 119       datap->first = 1;
 120       datap->nip = (service_user *) -1l;
 121       datap->known_groups = NULL;
 122       datap->needed_groups = NULL;
 123
 124       retval = 1;
 125     }
 126   else
 127     {
 128       if (__builtin_expect (netgroup_resp.found == -1, 0))
 129         {
 130           /* The daemon does not cache this database.  */
 131           __nss_not_use_nscd_netgroup = 1;
 132           goto out_close;
 133         }
 134
 135       /* Set errno to 0 to indicate no error, just no found record.  */
 136       __set_errno (0);
 137       /* Even though we have not found anything, the result is zero.  */
 138       retval = 0;
 139     }
 140
 141  out_close:
 142   if (sock != -1)
 143     close_not_cancel_no_status (sock);
 144  out:
 145   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
 146     {
 147       /* When we come here this means there has been a GC cycle while we
 148          were looking for the data.  This means the data might have been
 149          inconsistent.  Retry if possible.  */
 150       if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
 151         {
 152           /* nscd is just running gc now.  Disable using the mapping.  */
 153           if (atomic_decrement_val (&mapped->counter) == 0)
 154             __nscd_unmap (mapped);
 155           mapped = NO_MAPPING;
 156         }
 157
 158       if (retval != -1)
 159         goto retry;
 160     }
 161
 162   return retval;
 163 }
 164
 165
 166 int
 167 __nscd_innetgr (const char *netgroup, const char *host, const char *user,
 168                 const char *domain)
 169 {
 170   size_t key_len = (strlen (netgroup) + strlen (host ?: "")
 171                     + strlen (user ?: "") + strlen (domain ?: "") + 7);
 172   char *key;
 173   bool use_alloca = __libc_use_alloca (key_len);
 174   if (use_alloca)
 175     key = alloca (key_len);
 176   else
 177     {
 178       key = malloc (key_len);
 179       if (key == NULL)
 180         return -1;
 181     }
 182   char *wp = stpcpy (key, netgroup) + 1;
 183   if (host != NULL)
 184     {
 185       *wp++ = '\1';
 186       wp = stpcpy (wp, host) + 1;
 187     }
 188   else
 189     *wp++ = '\0';
 190   if (user != NULL)
 191     {
 192       *wp++ = '\1';
 193       wp = stpcpy (wp, user) + 1;
 194     }
 195   else
 196     *wp++ = '\0';
 197   if (domain != NULL)
 198     {
 199       *wp++ = '\1';
 200       wp = stpcpy (wp, domain) + 1;
 201     }
 202   else
 203     *wp++ = '\0';
 204   key_len = wp - key;
 205
 206   /* If the mapping is available, try to search there instead of
 207      communicating with the nscd.  */
 208   int gc_cycle;
 209   int nretries = 0;
 210   struct mapped_database *mapped;
 211   mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
 212
 213  retry:;
 214   int retval = -1;
 215   innetgroup_response_header innetgroup_resp;
 216   int sock = -1;
 217
 218   if (mapped != NO_MAPPING)
 219     {
 220       struct datahead *found = __nscd_cache_search (INNETGR, key,
 221                                                     key_len, mapped,
 222                                                     sizeof innetgroup_resp);
 223       if (found != NULL)
 224         {
 225           innetgroup_resp = found->data[0].innetgroupdata;
 226           /* Now check if we can trust pw_resp fields.  If GC is
 227              in progress, it can contain anything.  */
 228           if (mapped->head->gc_cycle != gc_cycle)
 229             {
 230               retval = -2;
 231               goto out;
 232             }
 233
 234           goto found_entry;
 235         }
 236     }
 237
 238   sock = __nscd_open_socket (key, key_len, INNETGR,
 239                              &innetgroup_resp, sizeof (innetgroup_resp));
 240   if (sock == -1)
 241     {
 242       /* nscd not running or wrong version.  */
 243       __nss_not_use_nscd_netgroup = 1;
 244       goto out;
 245     }
 246
 247  found_entry:
 248   if (innetgroup_resp.found == 1)
 249     retval = innetgroup_resp.result;
 250   else
 251     {
 252       if (__builtin_expect (innetgroup_resp.found == -1, 0))
 253         {
 254           /* The daemon does not cache this database.  */
 255           __nss_not_use_nscd_netgroup = 1;
 256           goto out_close;
 257         }
 258
 259       /* Set errno to 0 to indicate no error, just no found record.  */
 260       __set_errno (0);
 261       /* Even though we have not found anything, the result is zero.  */
 262       retval = 0;
 263     }
 264
 265  out_close:
 266   if (sock != -1)
 267     close_not_cancel_no_status (sock);
 268  out:
 269   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
 270     {
 271       /* When we come here this means there has been a GC cycle while we
 272          were looking for the data.  This means the data might have been
 273          inconsistent.  Retry if possible.  */
 274       if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
 275         {
 276           /* nscd is just running gc now.  Disable using the mapping.  */
 277           if (atomic_decrement_val (&mapped->counter) == 0)
 278             __nscd_unmap (mapped);
 279           mapped = NO_MAPPING;
 280         }
 281
 282       if (retval != -1)
 283         goto retry;
 284     }
 285
 286   if (! use_alloca)
 287     free (key);
 288
 289   return retval;
 290 }