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