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glibc  2.9
Functions
digits_dots.c File Reference
#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"

Go to the source code of this file.

Functions

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 af, int *h_errnop)

Function Documentation

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  af,
int h_errnop 
)

Definition at line 37 of file digits_dots.c.

{
  int save;

  /* We have to test for the use of IPv6 which can only be done by
     examining `_res'.  */
  if (__res_maybe_init (&_res, 0) == -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;

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

       case AF_INET6:
         addr_size = IN6ADDRSZ;
         break;

       default:
         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 (af == AF_INET && (_res.options & RES_USE_INET6))
                  {
                    /* 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;

         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;
}

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