nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996, 1997, 1998 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 <errno.h>
  21 #include "nsswitch.h"
  22 #ifdef USE_NSCD
  23 # include <nscd/nscd_proto.h>
  24 #endif
  25 #ifdef NEED__RES_HCONF
  26 # include <resolv/res_hconf.h>
  27 #endif
  28
  29 /*******************************************************************\
  30 |* Here we assume several symbols to be defined:                   *|
  31 |*                                                                 *|
  32 |* LOOKUP_TYPE   - the return type of the function                 *|
  33 |*                                                                 *|
  34 |* FUNCTION_NAME - name of the non-reentrant function              *|
  35 |*                                                                 *|
  36 |* DATABASE_NAME - name of the database the function accesses      *|
  37 |*                 (e.g., host, services, ...)                     *|
  38 |*                                                                 *|
  39 |* ADD_PARAMS    - additional parameter, can vary in number        *|
  40 |*                                                                 *|
  41 |* ADD_VARIABLES - names of additional parameter                   *|
  42 |*                                                                 *|
  43 |* Optionally the following vars can be defined:                   *|
  44 |*                                                                 *|
  45 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  46 |*                 the global `h_errno' variable.                  *|
  47 |*                                                                 *|
  48 |* NEED__RES     - the global _res variable might be used so we    *|
  49 |*                 will have to initialize it if necessary         *|
  50 |*                                                                 *|
  51 \*******************************************************************/
  52
  53 /* To make the real sources a bit prettier.  */
  54 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
  55 #define APPEND_R(name) APPEND_R1 (name)
  56 #define APPEND_R1(name) name##_r
  57 #define INTERNAL(name) INTERNAL1 (name)
  58 #define INTERNAL1(name) __##name
  59
  60 #ifdef USE_NSCD
  61 # define NSCD_NAME ADD_NSCD (REENTRANT_NAME)
  62 # define ADD_NSCD(name) ADD_NSCD1 (name)
  63 # define ADD_NSCD1(name) __nscd_##name
  64 # define NOT_USENSCD_NAME ADD_NOT_NSCDUSE (DATABASE_NAME)
  65 # define ADD_NOT_NSCDUSE(name) ADD_NOT_NSCDUSE1 (name)
  66 # define ADD_NOT_NSCDUSE1(name) __nss_not_use_nscd_##name
  67 #endif
  68
  69 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  70 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  71 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  72 #define STRINGIZE(name) STRINGIZE1 (name)
  73 #define STRINGIZE1(name) #name
  74
  75 #define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  76 #define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  77 #define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  78
  79 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  80 #ifdef NEED_H_ERRNO
  81 # define H_ERRNO_PARM , int *h_errnop
  82 # define H_ERRNO_VAR , h_errnop
  83 #else
  84 # define H_ERRNO_PARM
  85 # define H_ERRNO_VAR
  86 #endif
  87
  88
  89 /* Type of the lookup function we need here.  */
  90 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
  91                                             size_t, int * H_ERRNO_PARM);
  92
  93 /* Some usages of this file might use this variable.  */
  94 extern struct __res_state _res;
  95
  96 /* The lookup function for the first entry of this service.  */
  97 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp);
  98
  99 /* Interval in which we transfer retry to contact the NSCD.  */
 100 #define NSS_NSCD_RETRY  100
 101
 102
 103 int
 104 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 105                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 106 {
 107   static service_user *startp = NULL;
 108   static lookup_function start_fct;
 109   service_user *nip;
 110   lookup_function fct;
 111   int no_more;
 112   enum nss_status status = NSS_STATUS_UNAVAIL;
 113 #ifdef USE_NSCD
 114   int nscd_status;
 115 #endif
 116
 117 #ifdef HANDLE_DIGITS_DOTS
 118 # define resbuf (*resbuf)
 119 # include "digits_dots.c"
 120 # undef resbuf
 121 #endif
 122
 123 #ifdef USE_NSCD
 124   if (NOT_USENSCD_NAME && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 125     NOT_USENSCD_NAME = 0;
 126
 127   if (!NOT_USENSCD_NAME)
 128     {
 129       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen
 130                                H_ERRNO_VAR);
 131       if (nscd_status < 1)
 132         {
 133           *result = nscd_status == 0 ? resbuf : NULL;
 134           return nscd_status;
 135         }
 136     }
 137 #endif
 138
 139   if (startp == NULL)
 140     {
 141       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, (void **) &fct);
 142       if (no_more)
 143         startp = (service_user *) -1l;
 144       else
 145         {
 146           startp = nip;
 147           start_fct = fct;
 148
 149 #ifdef NEED__RES
 150           /* The resolver code will really be used so we have to
 151              initialize it.  */
 152           if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 153             {
 154               *h_errnop = NETDB_INTERNAL;
 155               *result = NULL;
 156               return -1;
 157             }
 158 #endif /* need _res */
 159 #ifdef NEED__RES_HCONF
 160           if (!_res_hconf.initialized)
 161             _res_hconf_init ();
 162 #endif /* need _res_hconf */
 163         }
 164     }
 165   else
 166     {
 167       fct = start_fct;
 168       no_more = (nip = startp) == (service_user *) -1l;
 169     }
 170
 171   while (no_more == 0)
 172     {
 173       status = _CALL_DL_FCT (fct, (ADD_VARIABLES, resbuf, buffer, buflen,
 174                                    &errno H_ERRNO_VAR));
 175
 176       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 177          provided buffer is too small.  In this case we should give
 178          the user the possibility to enlarge the buffer and we should
 179          not simply go on with the next service (even if the TRYAGAIN
 180          action tells us so).  */
 181       if (status == NSS_STATUS_TRYAGAIN
 182 #ifdef NEED_H_ERRNO
 183           && *h_errnop == NETDB_INTERNAL
 184 #endif
 185           && errno == ERANGE)
 186         break;
 187
 188       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 189                             (void **) &fct, status, 0);
 190     }
 191
 192 #ifdef HANDLE_DIGITS_DOTS
 193 done:
 194 #endif
 195   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 196 #ifdef POSTPROCESS
 197   POSTPROCESS;
 198 #endif
 199   return status == NSS_STATUS_SUCCESS ? 0 : -1;
 200 }
 201
 202 #define do_weak_alias(n1, n2) weak_alias (n1, (n2))
 203 do_weak_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME)