nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include "nsswitch.h"
  21
  22 /*******************************************************************\
  23 |* Here we assume several symbols to be defined:                   *|
  24 |*                                                                 *|
  25 |* LOOKUP_TYPE   - the return type of the function                 *|
  26 |*                                                                 *|
  27 |* FUNCTION_NAME - name of the non-reentrant function              *|
  28 |*                                                                 *|
  29 |* DATABASE_NAME - name of the database the function accesses      *|
  30 |*                 (e.g., host, services, ...)                     *|
  31 |*                                                                 *|
  32 |* ADD_PARAMS    - additional parameter, can vary in number        *|
  33 |*                                                                 *|
  34 |* ADD_VARIABLES - names of additional parameter                   *|
  35 |*                                                                 *|
  36 |* Optionally the following vars can be defined:                   *|
  37 |*                                                                 *|
  38 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  39 |*                 the global `h_errno' variable.                  *|
  40 |*                                                                 *|
  41 |* NEED__RES     - the global _res variable might be used so we    *|
  42 |*                 will have to initialize it if necessary         *|
  43 |*                                                                 *|
  44 \*******************************************************************/
  45
  46 /* To make the real sources a bit prettier.  */
  47 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
  48 #define APPEND_R(name) APPEND_R1 (name)
  49 #define APPEND_R1(name) name##_r
  50 #define INTERNAL(name) INTERNAL1 (name)
  51 #define INTERNAL1(name) __##name
  52
  53 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  54 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  55 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  56 #define STRINGIZE(name) STRINGIZE1 (name)
  57 #define STRINGIZE1(name) #name
  58
  59 #define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  60 #define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  61 #define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  62
  63 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  64 #ifdef NEED_H_ERRNO
  65 # define H_ERRNO_PARM , int *h_errnop
  66 # define H_ERRNO_VAR , h_errnop
  67 #else
  68 # define H_ERRNO_PARM
  69 # define H_ERRNO_VAR
  70 #endif
  71
  72
  73 /* Type of the lookup function we need here.  */
  74 typedef int (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *, size_t
  75                                 H_ERRNO_PARM);
  76
  77 /* Some usages of this file might use this variable.  */
  78 extern struct __res_state _res;
  79
  80 /* The lookup function for the first entry of this service.  */
  81 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp);
  82
  83
  84
  85 int
  86 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
  87                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
  88 {
  89   static service_user *startp = NULL;
  90   static lookup_function start_fct;
  91   service_user *nip;
  92   lookup_function fct;
  93   int no_more;
  94   enum nss_status status = NSS_STATUS_UNAVAIL;
  95
  96   if (startp == NULL)
  97     {
  98       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, (void **) &fct);
  99       if (no_more)
 100         startp = (service_user *) -1l;
 101       else
 102         {
 103           startp = nip;
 104           start_fct = fct;
 105
 106 #ifdef NEED__RES
 107           /* The resolver code will really be used so we have to
 108              initialize it.  */
 109           if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 110             {
 111               *h_errnop = NETDB_INTERNAL;
 112               *result = NULL;
 113               return -1;
 114             }
 115 #endif /* need _res */
 116         }
 117     }
 118   else
 119     {
 120       fct = start_fct;
 121       no_more = (nip = startp) == (service_user *) -1l;
 122     }
 123
 124   while (no_more == 0)
 125     {
 126       status = (*fct) (ADD_VARIABLES, resbuf, buffer, buflen H_ERRNO_VAR);
 127
 128       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 129                             (void **) &fct, status, 0);
 130     }
 131
 132   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 133   return status == NSS_STATUS_SUCCESS ? 0 : -1;
 134 }
 135
 136 #define do_weak_alias(n1, n2) weak_alias ((n1), (n2))
 137 do_weak_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME)