Remove trailing white space.

[glibc.git] / nss / nss_files / files-hosts.c

/* Hosts file parser in nss_files module.
   Copyright (C) 1996-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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 <assert.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>


/* Get implementation for some internal functions.  */
#include "../resolv/mapv4v6addr.h"
#include "../resolv/res_hconf.h"


#define ENTNAME         hostent
#define DATABASE        "hosts"
#define NEED_H_ERRNO

#define EXTRA_ARGS       , af, flags
#define EXTRA_ARGS_DECL  , int af, int flags

#define ENTDATA hostent_data
struct hostent_data
  {
    unsigned char host_addr[16]; /* IPv4 or IPv6 address.  */
    char *h_addr_ptrs[2];       /* Points to that and null terminator.  */
  };

#define TRAILING_LIST_MEMBER            h_aliases
#define TRAILING_LIST_SEPARATOR_P       isspace
#include "files-parse.c"
LINE_PARSER
("#",
 {
   char *addr;

   STRING_FIELD (addr, isspace, 1);

   /* Parse address.  */
   if (inet_pton (af == AF_UNSPEC ? AF_INET : af, addr, entdata->host_addr)
       > 0)
     af = af == AF_UNSPEC ? AF_INET : af;
   else
     {
       if (af == AF_INET6 && (flags & AI_V4MAPPED) != 0
           && inet_pton (AF_INET, addr, entdata->host_addr) > 0)
         map_v4v6_address ((char *) entdata->host_addr,
                           (char *) entdata->host_addr);
       else if (af == AF_INET
                && inet_pton (AF_INET6, addr, entdata->host_addr) > 0)
         {
           if (IN6_IS_ADDR_V4MAPPED (entdata->host_addr))
             memcpy (entdata->host_addr, entdata->host_addr + 12, INADDRSZ);
           else if (IN6_IS_ADDR_LOOPBACK (entdata->host_addr))
             {
               in_addr_t localhost = htonl (INADDR_LOOPBACK);
               memcpy (entdata->host_addr, &localhost, sizeof (localhost));
             }
           else
             /* Illegal address: ignore line.  */
             return 0;
         }
       else if (af == AF_UNSPEC
                && inet_pton (AF_INET6, addr, entdata->host_addr) > 0)
         af = AF_INET6;
       else
         /* Illegal address: ignore line.  */
         return 0;
     }

   /* We always return entries of the requested form.  */
   result->h_addrtype = af;
   result->h_length = af == AF_INET ? INADDRSZ : IN6ADDRSZ;

   /* Store a pointer to the address in the expected form.  */
   entdata->h_addr_ptrs[0] = (char *) entdata->host_addr;
   entdata->h_addr_ptrs[1] = NULL;
   result->h_addr_list = entdata->h_addr_ptrs;

   STRING_FIELD (result->h_name, isspace, 1);
 })

#define EXTRA_ARGS_VALUE \
  , ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET),                    \
  ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
#include "files-XXX.c"
#undef EXTRA_ARGS_VALUE

/* We only need to consider IPv4 mapped addresses if the input to the
   gethostbyaddr() function is an IPv6 address.  */
#define EXTRA_ARGS_VALUE \
  , af, (len == IN6ADDRSZ ? AI_V4MAPPED : 0)
DB_LOOKUP (hostbyaddr, ,,,
           {
             if (result->h_length == (int) len
                 && ! memcmp (addr, result->h_addr_list[0], len))
               break;
           }, const void *addr, socklen_t len, int af)
#undef EXTRA_ARGS_VALUE

enum nss_status
_nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
                             char *buffer, size_t buflen, int *errnop,
                             int *herrnop, int32_t *ttlp, char **canonp)
{
  uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct hostent_data);
  buffer += pad;
  buflen = buflen > pad ? buflen - pad : 0;

  __libc_lock_lock (lock);

  /* Reset file pointer to beginning or open file.  */
  enum nss_status status = internal_setent (keep_stream);

  if (status == NSS_STATUS_SUCCESS)
    {
      /* XXX Is using _res to determine whether we want to convert IPv4
         addresses to IPv6 addresses really the right thing to do?  */
      int flags = ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0);

      /* Tell getent function that we have repositioned the file pointer.  */
      last_use = getby;

      while ((status = internal_getent (result, buffer, buflen, errnop,
                                        herrnop, af, flags))
             == NSS_STATUS_SUCCESS)
        {
          LOOKUP_NAME_CASE (h_name, h_aliases)
        }

      if (status == NSS_STATUS_SUCCESS
          && _res_hconf.flags & HCONF_FLAG_MULTI)
        {
          /* We have to get all host entries from the file.  */
          size_t tmp_buflen = MIN (buflen, 4096);
          char tmp_buffer_stack[tmp_buflen]
            __attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));
          char *tmp_buffer = tmp_buffer_stack;
          struct hostent tmp_result_buf;
          int naddrs = 1;
          int naliases = 0;
          char *bufferend;
          bool tmp_buffer_malloced = false;

          while (result->h_aliases[naliases] != NULL)
            ++naliases;

          bufferend = (char *) &result->h_aliases[naliases + 1];

        again:
          while ((status = internal_getent (&tmp_result_buf, tmp_buffer,
                                            tmp_buflen, errnop, herrnop, af,
                                            flags))
                 == NSS_STATUS_SUCCESS)
            {
              int matches = 1;
              struct hostent *old_result = result;
              result = &tmp_result_buf;
              /* The following piece is a bit clumsy but we want to use the
                 `LOOKUP_NAME_CASE' value.  The optimizer should do its
                 job.  */
              do
                {
                  LOOKUP_NAME_CASE (h_name, h_aliases)
                  result = old_result;
                }
              while ((matches = 0));

              if (matches)
                {
                  /* We could be very clever and try to recycle a few bytes
                     in the buffer instead of generating new arrays.  But
                     we are not doing this here since it's more work than
                     it's worth.  Simply let the user provide a bit bigger
                     buffer.  */
                  char **new_h_addr_list;
                  char **new_h_aliases;
                  int newaliases = 0;
                  size_t newstrlen = 0;
                  int cnt;

                  /* Count the new aliases and the length of the strings.  */
                  while (tmp_result_buf.h_aliases[newaliases] != NULL)
                    {
                      char *cp = tmp_result_buf.h_aliases[newaliases];
                      ++newaliases;
                      newstrlen += strlen (cp) + 1;
                    }
                  /* If the real name is different add it also to the
                     aliases.  This means that there is a duplication
                     in the alias list but this is really the user's
                     problem.  */
                  if (strcmp (old_result->h_name,
                              tmp_result_buf.h_name) != 0)
                    {
                      ++newaliases;
                      newstrlen += strlen (tmp_result_buf.h_name) + 1;
                    }

                  /* Make sure bufferend is aligned.  */
                  assert ((bufferend - (char *) 0) % sizeof (char *) == 0);

                  /* Now we can check whether the buffer is large enough.
                     16 is the maximal size of the IP address.  */
                  if (bufferend + 16 + (naddrs + 2) * sizeof (char *)
                      + roundup (newstrlen, sizeof (char *))
                      + (naliases + newaliases + 1) * sizeof (char *)
                      >= buffer + buflen)
                    {
                      *errnop = ERANGE;
                      *herrnop = NETDB_INTERNAL;
                      status = NSS_STATUS_TRYAGAIN;
                      goto out;
                    }

                  new_h_addr_list =
                    (char **) (bufferend
                               + roundup (newstrlen, sizeof (char *))
                               + 16);
                  new_h_aliases =
                    (char **) ((char *) new_h_addr_list
                               + (naddrs + 2) * sizeof (char *));

                  /* Copy the old data in the new arrays.  */
                  for (cnt = 0; cnt < naddrs; ++cnt)
                    new_h_addr_list[cnt] = old_result->h_addr_list[cnt];

                  for (cnt = 0; cnt < naliases; ++cnt)
                    new_h_aliases[cnt] = old_result->h_aliases[cnt];

                  /* Store the new strings.  */
                  cnt = 0;
                  while (tmp_result_buf.h_aliases[cnt] != NULL)
                    {
                      new_h_aliases[naliases++] = bufferend;
                      bufferend = (__stpcpy (bufferend,
                                             tmp_result_buf.h_aliases[cnt])
                                   + 1);
                      ++cnt;
                    }

                  if (cnt < newaliases)
                    {
                      new_h_aliases[naliases++] = bufferend;
                      bufferend = __stpcpy (bufferend,
                                            tmp_result_buf.h_name) + 1;
                    }

                  /* Final NULL pointer.  */
                  new_h_aliases[naliases] = NULL;

                  /* Round up the buffer end address.  */
                  bufferend += (sizeof (char *)
                                - ((bufferend - (char *) 0)
                                   % sizeof (char *))) % sizeof (char *);

                  /* Now the new address.  */
                  new_h_addr_list[naddrs++] =
                    memcpy (bufferend, tmp_result_buf.h_addr,
                            tmp_result_buf.h_length);

                  /* Also here a final NULL pointer.  */
                  new_h_addr_list[naddrs] = NULL;

                  /* Store the new array pointers.  */
                  old_result->h_aliases = new_h_aliases;
                  old_result->h_addr_list = new_h_addr_list;

                  /* Compute the new buffer end.  */
                  bufferend = (char *) &new_h_aliases[naliases + 1];
                  assert (bufferend <= buffer + buflen);

                  result = old_result;
                }
            }

          if (status == NSS_STATUS_TRYAGAIN)
            {
              size_t newsize = 2 * tmp_buflen;
              if (tmp_buffer_malloced)
                {
                  char *newp = realloc (tmp_buffer, newsize);
                  if (newp != NULL)
                    {
                      assert ((((uintptr_t) newp)
                               & (__alignof__ (struct hostent_data) - 1))
                              == 0);
                      tmp_buffer = newp;
                      tmp_buflen = newsize;
                      goto again;
                    }
                }
              else if (!__libc_use_alloca (buflen + newsize))
                {
                  tmp_buffer = malloc (newsize);
                  if (tmp_buffer != NULL)
                    {
                      assert ((((uintptr_t) tmp_buffer)
                               & (__alignof__ (struct hostent_data) - 1))
                              == 0);
                      tmp_buffer_malloced = true;
                      tmp_buflen = newsize;
                      goto again;
                    }
                }
              else
                {
                  tmp_buffer
                    = extend_alloca (tmp_buffer, tmp_buflen,
                                     newsize
                                     + __alignof__ (struct hostent_data));
                  tmp_buffer = (char *) (((uintptr_t) tmp_buffer
                                          + __alignof__ (struct hostent_data)
                                          - 1)
                                         & ~(__alignof__ (struct hostent_data)
                                             - 1));
                  goto again;
                }
            }
          else
            status = NSS_STATUS_SUCCESS;
        out:
          if (tmp_buffer_malloced)
            free (tmp_buffer);
        }

      if (! keep_stream)
        internal_endent ();
    }

  if (canonp && status == NSS_STATUS_SUCCESS)
    *canonp = result->h_name;

  __libc_lock_unlock (lock);

  return status;
}

enum nss_status
_nss_files_gethostbyname_r (const char *name, struct hostent *result,
                            char *buffer, size_t buflen, int *errnop,
                            int *herrnop)
{
  int af = ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET);

  return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
                                      errnop, herrnop, NULL, NULL);
}

enum nss_status
_nss_files_gethostbyname2_r (const char *name, int af, struct hostent *result,
                             char *buffer, size_t buflen, int *errnop,
                             int *herrnop)
{
  return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
                                      errnop, herrnop, NULL, NULL);
}

enum nss_status
_nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,
                             char *buffer, size_t buflen, int *errnop,
                             int *herrnop, int32_t *ttlp)
{
  __libc_lock_lock (lock);

  /* Reset file pointer to beginning or open file.  */
  enum nss_status status = internal_setent (keep_stream);

  if (status == NSS_STATUS_SUCCESS)
    {
      /* Tell getent function that we have repositioned the file pointer.  */
      last_use = getby;

      bool any = false;
      bool got_canon = false;
      while (1)
        {
          /* Align the buffer for the next record.  */
          uintptr_t pad = (-(uintptr_t) buffer
                           % __alignof__ (struct hostent_data));
          buffer += pad;
          buflen = buflen > pad ? buflen - pad : 0;

          struct hostent result;
          status = internal_getent (&result, buffer, buflen, errnop,
                                    herrnop, AF_UNSPEC, 0);
          if (status != NSS_STATUS_SUCCESS)
            break;

          int naliases = 0;
          if (__strcasecmp (name, result.h_name) != 0)
            {
              for (; result.h_aliases[naliases] != NULL; ++naliases)
                if (! __strcasecmp (name, result.h_aliases[naliases]))
                  break;
              if (result.h_aliases[naliases] == NULL)
                continue;

              /* We know this alias exist.  Count it.  */
              ++naliases;
            }

          /* Determine how much memory has been used so far.  */
          // XXX It is not necessary to preserve the aliases array
          while (result.h_aliases[naliases] != NULL)
            ++naliases;
          char *bufferend = (char *) &result.h_aliases[naliases + 1];
          assert (buflen >= bufferend - buffer);
          buflen -= bufferend - buffer;
          buffer = bufferend;

          /* We found something.  */
          any = true;

          /* Create the record the caller expects.  There is only one
             address.  */
          assert (result.h_addr_list[1] == NULL);
          if (*pat == NULL)
            {
              uintptr_t pad = (-(uintptr_t) buffer
                               % __alignof__ (struct gaih_addrtuple));
              buffer += pad;
              buflen = buflen > pad ? buflen - pad : 0;

              if (__builtin_expect (buflen < sizeof (struct gaih_addrtuple),
                                    0))
                {
                  *errnop = ERANGE;
                  *herrnop = NETDB_INTERNAL;
                  status = NSS_STATUS_TRYAGAIN;
                  break;
                }

              *pat = (struct gaih_addrtuple *) buffer;
              buffer += sizeof (struct gaih_addrtuple);
              buflen -= sizeof (struct gaih_addrtuple);
            }

          (*pat)->next = NULL;
          (*pat)->name = got_canon ? NULL : result.h_name;
          got_canon = true;
          (*pat)->family = result.h_addrtype;
          memcpy ((*pat)->addr, result.h_addr_list[0], result.h_length);
          (*pat)->scopeid = 0;

          pat = &((*pat)->next);

          /* If we only look for the first matching entry we are done.  */
          if ((_res_hconf.flags & HCONF_FLAG_MULTI) == 0)
            break;
        }

      /* If we have to look for multiple records and found one, this
         is a success.  */
      if (status == NSS_STATUS_NOTFOUND && any)
        {
          assert ((_res_hconf.flags & HCONF_FLAG_MULTI) != 0);
          status = NSS_STATUS_SUCCESS;
        }

      if (! keep_stream)
        internal_endent ();
    }
  else if (status == NSS_STATUS_TRYAGAIN)
    {
      *errnop = errno;
      *herrnop = TRY_AGAIN;
    }
  else
    {
      *errnop = errno;
      *herrnop = NO_DATA;
    }

  __libc_lock_unlock (lock);

  return status;
}