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digits_dots.c

/* Copyright (C) 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by H.J. Lu <hjl@gnu.ai.mit.edu>, 1997.

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <assert.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <wctype.h>
#include <resolv.h>
#include <netdb.h>
#include <arpa/inet.h>
#include "nsswitch.h"

#ifdef USE_NSCD
# define inet_aton __inet_aton
# include <nscd/nscd_proto.h>
#endif

int
__nss_hostname_digits_dots (const char *name, struct hostent *resbuf,
                      char **buffer, size_t *buffer_size,
                      size_t buflen, struct hostent **result,
                      enum nss_status *status, int *typep,
                      int flags, int *afp, int *h_errnop)
{
  int save;

  /* We have to test for the use of IPv6 which can only be done by
     examining `_res'.  */
  if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
    {
      if (h_errnop)
      *h_errnop = NETDB_INTERNAL;
      *result = NULL;
      return -1;
    }

  /*
   * disallow names consisting only of digits/dots, unless
   * they end in a dot.
   */
  if (isdigit (name[0]) || isxdigit (name[0]) || name[0] == ':')
    {
      const char *cp;
      char *hostname;
      typedef unsigned char host_addr_t[16];
      host_addr_t *host_addr;
      typedef char *host_addr_list_t[2];
      host_addr_list_t *h_addr_ptrs;
      char **h_alias_ptr;
      size_t size_needed;
      int addr_size;
      int af;

      if (typep != NULL)
      af = *typep;
      else if (afp != NULL)
      af = *afp;
      else
      af = -1;

      switch (af)
      {
      case AF_INET:
        addr_size = INADDRSZ;
        break;

      case AF_INET6:
        addr_size = IN6ADDRSZ;
        break;

      default:
        if (typep != NULL)
          {
            /* This must not happen.  */
            if (h_errnop != NULL)
            *h_errnop = HOST_NOT_FOUND;
            goto done;
          }
        else
          {
            af = (_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET;
            addr_size = af == AF_INET6 ? IN6ADDRSZ : INADDRSZ;
          }
        break;
      }

      size_needed = (sizeof (*host_addr)
                 + sizeof (*h_addr_ptrs) + strlen (name) + 1);

      if (buffer_size == NULL)
        {
        if (buflen < size_needed)
          {
            if (h_errnop != NULL)
            *h_errnop = TRY_AGAIN;
            __set_errno (ERANGE);
            goto done;
          }
      }
      else if (buffer_size != NULL && *buffer_size < size_needed)
      {
        char *new_buf;
        *buffer_size = size_needed;
        new_buf = (char *) realloc (*buffer, *buffer_size);

        if (new_buf == NULL)
          {
            save = errno;
            free (*buffer);
            *buffer = NULL;
            *buffer_size = 0;
            __set_errno (save);
            if (h_errnop != NULL)
            *h_errnop = TRY_AGAIN;
            *result = NULL;
            goto done;
          }
        *buffer = new_buf;
      }

      memset (*buffer, '\0', size_needed);

      host_addr = (host_addr_t *) *buffer;
      h_addr_ptrs = (host_addr_list_t *)
      ((char *) host_addr + sizeof (*host_addr));
      h_alias_ptr = (char **) ((char *) h_addr_ptrs + sizeof (*h_addr_ptrs));
      hostname = (char *) h_alias_ptr + sizeof (*h_alias_ptr);

      if (isdigit (name[0]))
      {
        for (cp = name;; ++cp)
          {
            if (*cp == '\0')
            {
              int ok;

              if (*--cp == '.')
                break;

              /* All-numeric, no dot at the end. Fake up a hostent as if
                 we'd actually done a lookup.  What if someone types
                 255.255.255.255?  The test below will succeed
                 spuriously... ???  */
              if (af == AF_INET)
                ok = __inet_aton (name, (struct in_addr *) host_addr);
              else
                {
                  assert (af == AF_INET6);
                  ok = inet_pton (af, name, host_addr) > 0;
                }
              if (! ok)
                {
                  *h_errnop = HOST_NOT_FOUND;
                  if (buffer_size)
                  *result = NULL;
                  goto done;
                }

              resbuf->h_name = strcpy (hostname, name);
              h_alias_ptr[0] = NULL;
              resbuf->h_aliases = h_alias_ptr;
              (*h_addr_ptrs)[0] = (char *) host_addr;
              (*h_addr_ptrs)[1] = NULL;
              resbuf->h_addr_list = *h_addr_ptrs;
              if ((typep != NULL && *typep == AF_INET6)
                  || (af == AF_INET
                    && (_res.options & RES_USE_INET6)))
                {
                  if (typep != NULL && (flags & AI_V4MAPPED) == 0)
                  {
                    /* That's bad.  The user hasn't specified that she
                       allows IPv4 numeric addresses.  */
                    *result = NULL;
                    *h_errnop = HOST_NOT_FOUND;
                    goto done;
                  }
                  else
                  {
                    /* We need to change the IP v4 address into the
                       IP v6 address.  */
                    char tmp[INADDRSZ];
                    char *p = (char *) host_addr;
                    int i;

                    /* Save a copy of the IP v4 address. */
                    memcpy (tmp, host_addr, INADDRSZ);
                    /* Mark this ipv6 addr as a mapped ipv4. */
                    for (i = 0; i < 10; i++)
                      *p++ = 0x00;
                    *p++ = 0xff;
                    *p++ = 0xff;
                    /* Copy the IP v4 address. */
                    memcpy (p, tmp, INADDRSZ);
                    resbuf->h_addrtype = AF_INET6;
                    resbuf->h_length = IN6ADDRSZ;
                  }
                }
              else
                {
                  resbuf->h_addrtype = af;
                  resbuf->h_length = addr_size;
                }
              if (h_errnop != NULL)
                *h_errnop = NETDB_SUCCESS;
              if (buffer_size == NULL)
                *status = NSS_STATUS_SUCCESS;
              else
               *result = resbuf;
              goto done;
            }

            if (!isdigit (*cp) && *cp != '.')
            break;
          }
      }

      if ((isxdigit (name[0]) && strchr (name, ':') != NULL) || name[0] == ':')
      {
        const char *cp;
        char *hostname;
        typedef unsigned char host_addr_t[16];
        host_addr_t *host_addr;
        typedef char *host_addr_list_t[2];
        host_addr_list_t *h_addr_ptrs;
        size_t size_needed;
        int addr_size;
        int af;

        if (typep != NULL)
          af = *typep;
        else if (afp != NULL)
          af = *afp;
        else
          af = -1;

        switch (af)
          {
          default:
            af = (_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET;
            if (af == AF_INET6)
            {
              addr_size = IN6ADDRSZ;
              break;
            }
            /* FALLTHROUGH */

          case AF_INET:
            /* This is not possible.  We cannot represent an IPv6 address
             in an `struct in_addr' variable.  */
            *h_errnop = HOST_NOT_FOUND;
            *result = NULL;
            goto done;

          case AF_INET6:
            addr_size = IN6ADDRSZ;
            break;
          }

        size_needed = (sizeof (*host_addr)
                   + sizeof (*h_addr_ptrs) + strlen (name) + 1);

        if (buffer_size == NULL && buflen < size_needed)
          {
            if (h_errnop != NULL)
            *h_errnop = TRY_AGAIN;
            __set_errno (ERANGE);
            goto done;
          }
        else if (buffer_size != NULL && *buffer_size < size_needed)
          {
            char *new_buf;
            *buffer_size = size_needed;
            new_buf = realloc (*buffer, *buffer_size);

            if (new_buf == NULL)
            {
              save = errno;
              free (*buffer);
              __set_errno (save);
              *buffer = NULL;
              *buffer_size = 0;
              *result = NULL;
              goto done;
            }
            *buffer = new_buf;
          }

        memset (*buffer, '\0', size_needed);

        host_addr = (host_addr_t *) *buffer;
        h_addr_ptrs = (host_addr_list_t *)
          ((char *) host_addr + sizeof (*host_addr));
        hostname = (char *) h_addr_ptrs + sizeof (*h_addr_ptrs);

        for (cp = name;; ++cp)
          {
            if (!*cp)
            {
              if (*--cp == '.')
                break;

              /* All-IPv6-legal, no dot at the end. Fake up a
                 hostent as if we'd actually done a lookup.  */
              if (inet_pton (AF_INET6, name, host_addr) <= 0)
                {
                  *h_errnop = HOST_NOT_FOUND;
                  if (buffer_size)
                  *result = NULL;
                  goto done;
                }

              resbuf->h_name = strcpy (hostname, name);
              h_alias_ptr[0] = NULL;
              resbuf->h_aliases = h_alias_ptr;
              (*h_addr_ptrs)[0] = (char *) host_addr;
              (*h_addr_ptrs)[1] = (char *) 0;
              resbuf->h_addr_list = *h_addr_ptrs;
              resbuf->h_addrtype = AF_INET6;
              resbuf->h_length = addr_size;
              *h_errnop = NETDB_SUCCESS;
              if (buffer_size == NULL)
                *status = NSS_STATUS_SUCCESS;
              else
                *result = resbuf;
              goto done;
            }

            if (!isxdigit (*cp) && *cp != ':' && *cp != '.')
            break;
          }
      }
    }

  return 0;

done:
  return 1;
}
libc_hidden_def (__nss_hostname_digits_dots)

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