1: /* Copyright (C) 1996-2001,2003, 2004 Free Software Foundation, Inc.
    2:    This file is part of the GNU C Library.
    3: 
    4:    The GNU C Library is free software; you can redistribute it and/or
    5:    modify it under the terms of the GNU Lesser General Public
    6:    License as published by the Free Software Foundation; either
    7:    version 2.1 of the License, or (at your option) any later version.
    8: 
    9:    The GNU C Library is distributed in the hope that it will be useful,
   10:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   11:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   12:    Lesser General Public License for more details.
   13: 
   14:    You should have received a copy of the GNU Lesser General Public
   15:    License along with the GNU C Library; if not, write to the Free
   16:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   17:    02111-1307 USA.  */
   18: 
   19: #include <assert.h>
   20: #include <errno.h>
   21: #include <bits/libc-lock.h>
   22: #include <stdlib.h>
   23: #include <resolv.h>
   24: 
   25: #include "nsswitch.h"
   26: 
   27: /*******************************************************************\
   28: |* Here we assume several symbols to be defined:                   *|
   29: |*                                                                 *|
   30: |* LOOKUP_TYPE   - the return type of the function                 *|
   31: |*                                                                 *|
   32: |* FUNCTION_NAME - name of the non-reentrant function              *|
   33: |*                                                                 *|
   34: |* DATABASE_NAME - name of the database the function accesses      *|
   35: |*                 (e.g., host, services, ...)                         *|
   36: |*                                                                 *|
   37: |* ADD_PARAMS    - additional parameter, can vary in number        *|
   38: |*                                                                 *|
   39: |* ADD_VARIABLES - names of additional parameter                   *|
   40: |*                                                                 *|
   41: |* BUFLEN        - length of buffer allocated for the non        *|
   42: |*                 reentrant version                                   *|
   43: |*                                                                 *|
   44: |* Optionally the following vars can be defined:                   *|
   45: |*                                                                 *|
   46: |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
   47: |*                 the global `h_errno' variable.              *|
   48: |*                                                                 *|
   49: \*******************************************************************/
   50: 
   51: /* To make the real sources a bit prettier.  */
   52: #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
   53: #define APPEND_R(name) APPEND_R1 (name)
   54: #define APPEND_R1(name) name##_r
   55: #define INTERNAL(name) INTERNAL1 (name)
   56: #define INTERNAL1(name) __##name
   57: 
   58: /* Sometimes we need to store error codes in the `h_errno' variable.  */
   59: #ifdef NEED_H_ERRNO
   60: # define H_ERRNO_PARM , int *h_errnop
   61: # define H_ERRNO_VAR , &h_errno_tmp
   62: # define H_ERRNO_VAR_P &h_errno_tmp
   63: #else
   64: # define H_ERRNO_PARM
   65: # define H_ERRNO_VAR
   66: # define H_ERRNO_VAR_P NULL
   67: #endif
   68: 
   69: #ifdef HAVE_AF
   70: # define AF_VAL af
   71: #else
   72: # define AF_VAL AF_INET
   73: #endif
   74: 
   75: /* Prototype for reentrant version we use here.  */
   76: extern int INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf,
   77:                                       char *buffer, size_t buflen,
   78:                                       LOOKUP_TYPE **result H_ERRNO_PARM);
   79: 
   80: /* We need to protect the dynamic buffer handling.  */
   81: __libc_lock_define_initialized (static, lock);
   82: 
   83: /* This points to the static buffer used.  */
   84: libc_freeres_ptr (static char *buffer);
   85: 
   86: 
   87: LOOKUP_TYPE *
   88: FUNCTION_NAME (ADD_PARAMS)
   89: {
   90:   static size_t buffer_size;
   91:   static LOOKUP_TYPE resbuf;
   92:   LOOKUP_TYPE *result;
   93: #ifdef NEED_H_ERRNO
   94:   int h_errno_tmp = 0;
   95: #endif
   96: 
   97:   /* Get lock.  */
   98:   __libc_lock_lock (lock);
   99: 
  100:   if (buffer == NULL)
  101:     {
  102:       buffer_size = BUFLEN;
  103:       buffer = (char *) malloc (buffer_size);
  104:     }
  105: 
  106: #ifdef HANDLE_DIGITS_DOTS
  107:   if (buffer != NULL)
  108:     {
  109:       if (__nss_hostname_digits_dots (name, &resbuf, &buffer,
  110:                                       &buffer_size, 0, &result, NULL, AF_VAL,
  111:                                       H_ERRNO_VAR_P))
  112:         goto done;
  113:     }
  114: #endif
  115: 
  116:   while (buffer != NULL
  117:          && (INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, &resbuf, buffer,
  118:                                         buffer_size, &result H_ERRNO_VAR)
  119:              == ERANGE)
  120: #ifdef NEED_H_ERRNO
  121:          && h_errno_tmp == NETDB_INTERNAL
  122: #endif
  123:          )
  124:     {
  125:       char *new_buf;
  126:       buffer_size *= 2;
  127:       new_buf = (char *) realloc (buffer, buffer_size);
  128:       if (new_buf == NULL)
  129:         {
  130:           /* We are out of memory.  Free the current buffer so that the
  131:              process gets a chance for a normal termination.  */
  132:           free (buffer);
  133:           __set_errno (ENOMEM);
  134:         }
  135:       buffer = new_buf;
  136:     }
  137: 
  138:   if (buffer == NULL)
  139:     result = NULL;
  140: 
  141: #ifdef HANDLE_DIGITS_DOTS
  142: done:
  143: #endif
  144:   /* Release lock.  */
  145:   __libc_lock_unlock (lock);
  146: 
  147: #ifdef NEED_H_ERRNO
  148:   if (h_errno_tmp != 0)
  149:     __set_h_errno (h_errno_tmp);
  150: #endif
  151: 
  152:   return result;
  153: }
  154: 
  155: static_link_warning (FUNCTION_NAME)