nss/nss_files/files-hosts.c

   1 /* Hosts file parser in nss_files module.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <assert.h>
  21 #include <netinet/in.h>
  22 #include <arpa/inet.h>
  23 #include <arpa/nameser.h>
  24 #include <netdb.h>
  25 #include <resolv.h>
  26
  27
  28 /* Get implementation for some internal functions.  */
  29 #include "../resolv/mapv4v6addr.h"
  30 #include "../resolv/res_hconf.h"
  31
  32
  33 #define ENTNAME         hostent
  34 #define DATABASE        "hosts"
  35 #define NEED_H_ERRNO
  36
  37 #define EXTRA_ARGS       , af, flags
  38 #define EXTRA_ARGS_DECL  , int af, int flags
  39
  40 #define ENTDATA hostent_data
  41 struct hostent_data
  42   {
  43     unsigned char host_addr[16]; /* IPv4 or IPv6 address.  */
  44     char *h_addr_ptrs[2];       /* Points to that and null terminator.  */
  45   };
  46
  47 #define TRAILING_LIST_MEMBER            h_aliases
  48 #define TRAILING_LIST_SEPARATOR_P       isspace
  49 #include "files-parse.c"
  50 LINE_PARSER
  51 ("#",
  52  {
  53    char *addr;
  54
  55    STRING_FIELD (addr, isspace, 1);
  56
  57    /* Parse address.  */
  58    if (inet_pton (af, addr, entdata->host_addr) <= 0
  59        && (af != AF_INET6 || (flags & AI_V4MAPPED) == 0
  60            || inet_pton (AF_INET, addr, entdata->host_addr) <= 0
  61            || (map_v4v6_address ((char *) entdata->host_addr,
  62                                  (char *) entdata->host_addr),
  63                0)))
  64      /* Illegal address: ignore line.  */
  65      return 0;
  66
  67    /* We always return entries of the requested form.  */
  68    result->h_addrtype = af;
  69    result->h_length = af == AF_INET ? INADDRSZ : IN6ADDRSZ;
  70
  71    /* Store a pointer to the address in the expected form.  */
  72    entdata->h_addr_ptrs[0] = entdata->host_addr;
  73    entdata->h_addr_ptrs[1] = NULL;
  74    result->h_addr_list = entdata->h_addr_ptrs;
  75
  76    STRING_FIELD (result->h_name, isspace, 1);
  77  })
  78
  79
  80
  81 #define HOST_DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
  82 enum nss_status                                                               \
  83 _nss_files_get##name##_r (proto,                                              \
  84                           struct STRUCTURE *result, char *buffer,             \
  85                           size_t buflen, int *errnop H_ERRNO_PROTO)           \
  86 {                                                                             \
  87   enum nss_status status;                                                     \
  88                                                                               \
  89   __libc_lock_lock (lock);                                                    \
  90                                                                               \
  91   /* Reset file pointer to beginning or open file.  */                        \
  92   status = internal_setent (keep_stream);                                     \
  93                                                                               \
  94   if (status == NSS_STATUS_SUCCESS)                                           \
  95     {                                                                         \
  96       /* Tell getent function that we have repositioned the file pointer.  */ \
  97       last_use = getby;                                                       \
  98                                                                               \
  99       while ((status = internal_getent (result, buffer, buflen, errnop        \
 100                                         H_ERRNO_ARG EXTRA_ARGS_VALUE))        \
 101              == NSS_STATUS_SUCCESS)                                           \
 102         { break_if_match }                                                    \
 103                                                                               \
 104       if (status == NSS_STATUS_SUCCESS                                        \
 105           && _res_hconf.flags & HCONF_FLAG_MULTI)                             \
 106         {                                                                     \
 107           /* We have to get all host entries from the file.  */               \
 108           const size_t tmp_buflen = MIN (buflen, 4096);                       \
 109           char tmp_buffer[tmp_buflen];                                        \
 110           struct hostent tmp_result_buf;                                      \
 111           int naddrs = 1;                                                     \
 112           int naliases = 0;                                                   \
 113           char *bufferend;                                                    \
 114                                                                               \
 115           while (result->h_aliases[naliases] != NULL)                         \
 116             ++naliases;                                                       \
 117                                                                               \
 118           bufferend = (char *) &result->h_aliases[naliases + 1];              \
 119                                                                               \
 120           while ((status = internal_getent (&tmp_result_buf, tmp_buffer,      \
 121                                             tmp_buflen, errnop H_ERRNO_ARG    \
 122                                             EXTRA_ARGS_VALUE))                \
 123                  == NSS_STATUS_SUCCESS)                                       \
 124             {                                                                 \
 125               int matches = 1;                                                \
 126               struct hostent *old_result = result;                            \
 127               result = &tmp_result_buf;                                       \
 128               /* The following piece is a bit clumsy but we want to use the   \
 129                  `break_if_match' value.  The optimizer should do its         \
 130                  job.  */                                                     \
 131               do                                                              \
 132                 {                                                             \
 133                   break_if_match                                              \
 134                   result = old_result;                                        \
 135                 }                                                             \
 136               while ((matches = 0));                                          \
 137                                                                               \
 138               if (matches)                                                    \
 139                 {                                                             \
 140                   /* We could be very clever and try to recycle a few bytes   \
 141                      in the buffer instead of generating new arrays.  But     \
 142                      we are not doing this here since it's more work than     \
 143                      it's worth.  Simply let the user provide a bit bigger    \
 144                      buffer.  */                                              \
 145                   char **new_h_addr_list;                                     \
 146                   char **new_h_aliases;                                       \
 147                   int newaliases = 0;                                         \
 148                   size_t newstrlen = 0;                                       \
 149                   int cnt;                                                    \
 150                                                                               \
 151                   /* Count the new aliases and the length of the strings.  */ \
 152                   while (tmp_result_buf.h_aliases[newaliases] != NULL)        \
 153                     {                                                         \
 154                       char *cp = tmp_result_buf.h_aliases[newaliases];        \
 155                       ++newaliases;                                           \
 156                       newstrlen += strlen (cp) + 1;                           \
 157                     }                                                         \
 158                   /* If the real name is different add it also to the         \
 159                      aliases.  This means that there is a duplication         \
 160                      in the alias list but this is really the users           \
 161                      problem.  */                                             \
 162                   if (strcmp (old_result->h_name,                             \
 163                               tmp_result_buf.h_name) != 0)                    \
 164                     {                                                         \
 165                       ++newaliases;                                           \
 166                       newstrlen += strlen (tmp_result_buf.h_name) + 1;        \
 167                     }                                                         \
 168                                                                               \
 169                   /* Now we can check whether the buffer is large enough.  */ \
 170                   if (bufferend + 16 + (naddrs + 2) * sizeof (char *)         \
 171                       + roundup (newstrlen, sizeof (char *))                  \
 172                       + (naliases + newaliases + 1) * sizeof (char *)         \
 173                       >= buffer + buflen)                                     \
 174                     {                                                         \
 175                       *errnop = ERANGE;                                       \
 176                       status = NSS_STATUS_TRYAGAIN;                           \
 177                       break;                                                  \
 178                     }                                                         \
 179                                                                               \
 180                   new_h_addr_list =                                           \
 181                     (char **) (bufferend                                      \
 182                                + roundup (newstrlen, sizeof (char *))         \
 183                                + 16);                                         \
 184                   new_h_aliases =                                             \
 185                     (char **) ((char *) new_h_addr_list                       \
 186                                + (naddrs + 2) * sizeof (char *));             \
 187                                                                               \
 188                   /* Copy the old data in the new arrays.  */                 \
 189                   for (cnt = 0; cnt < naddrs; ++cnt)                          \
 190                     new_h_addr_list[cnt] = old_result->h_addr_list[cnt];      \
 191                                                                               \
 192                   for (cnt = 0; cnt < naliases; ++cnt)                        \
 193                     new_h_aliases[cnt] = old_result->h_aliases[cnt];          \
 194                                                                               \
 195                   /* Store the new strings.  */                               \
 196                   cnt = 0;                                                    \
 197                   while (tmp_result_buf.h_aliases[cnt] != NULL)               \
 198                     {                                                         \
 199                       new_h_aliases[naliases++] = bufferend;                  \
 200                       bufferend = (__stpcpy (bufferend,                       \
 201                                              tmp_result_buf.h_aliases[cnt])   \
 202                                    + 1);                                      \
 203                       ++cnt;                                                  \
 204                     }                                                         \
 205                                                                               \
 206                   if (cnt < newaliases)                                       \
 207                     {                                                         \
 208                       new_h_aliases[naliases++] = bufferend;                  \
 209                       bufferend = __stpcpy (bufferend,                        \
 210                                             tmp_result_buf.h_name) + 1;       \
 211                     }                                                         \
 212                                                                               \
 213                   /* Final NULL pointer.  */                                  \
 214                   new_h_aliases[naliases] = NULL;                             \
 215                                                                               \
 216                   /* Round up the buffer end address.  */                     \
 217                   bufferend += (sizeof (char *)                               \
 218                                 - ((bufferend - (char *) 0)                   \
 219                                    % sizeof (char *)));                       \
 220                                                                               \
 221                   /* Now the new address.  */                                 \
 222                   new_h_addr_list[naddrs++] =                                 \
 223                     memcpy (bufferend, tmp_result_buf.h_addr,                 \
 224                             tmp_result_buf.h_length);                         \
 225                                                                               \
 226                   /* Also here a final NULL pointer.  */                      \
 227                   new_h_addr_list[naddrs] = NULL;                             \
 228                                                                               \
 229                   /* Store the new array pointers.  */                        \
 230                   old_result->h_aliases = new_h_aliases;                      \
 231                   old_result->h_addr_list = new_h_addr_list;                  \
 232                                                                               \
 233                   /* Compute the new buffer end.  */                          \
 234                   bufferend = (char *) &new_h_aliases[naliases + 1];          \
 235                   assert (bufferend <= buffer + buflen);                      \
 236                                                                               \
 237                   result = old_result;                                        \
 238                 }                                                             \
 239             }                                                                 \
 240                                                                               \
 241           if (status != NSS_STATUS_TRYAGAIN)                                  \
 242             status = NSS_STATUS_SUCCESS;                                      \
 243         }                                                                     \
 244                                                                               \
 245                                                                               \
 246       if (! keep_stream)                                                      \
 247         internal_endent ();                                                   \
 248     }                                                                         \
 249                                                                               \
 250   __libc_lock_unlock (lock);                                                  \
 251                                                                               \
 252   return status;                                                              \
 253 }
 254
 255
 256 #define EXTRA_ARGS_VALUE \
 257   , ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET),                    \
 258   ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
 259 #include "files-XXX.c"
 260 HOST_DB_LOOKUP (hostbyname, ,,
 261                 {
 262                   LOOKUP_NAME_CASE (h_name, h_aliases)
 263                 }, const char *name)
 264
 265
 266 #undef EXTRA_ARGS_VALUE
 267 /* XXX Is using _res to determine whether we want to convert IPv4 addresses
 268    to IPv6 addresses really the right thing to do?  */
 269 #define EXTRA_ARGS_VALUE \
 270   , af, ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
 271 HOST_DB_LOOKUP (hostbyname2, ,,
 272                 {
 273                   LOOKUP_NAME_CASE (h_name, h_aliases)
 274                 }, const char *name, int af)
 275
 276 DB_LOOKUP (hostbyaddr, ,,
 277            {
 278              if (result->h_length == len
 279                  && ! memcmp (addr, result->h_addr_list[0], len))
 280                break;
 281            }, const void *addr, socklen_t len, int af)