nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999 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 <assert.h>
  21 #include <errno.h>
  22 #include "nsswitch.h"
  23 #ifdef USE_NSCD
  24 # include <nscd/nscd_proto.h>
  25 #endif
  26 #ifdef NEED__RES_HCONF
  27 # include <resolv/res_hconf.h>
  28 #endif
  29
  30 /*******************************************************************\
  31 |* Here we assume several symbols to be defined:                   *|
  32 |*                                                                 *|
  33 |* LOOKUP_TYPE   - the return type of the function                 *|
  34 |*                                                                 *|
  35 |* FUNCTION_NAME - name of the non-reentrant function              *|
  36 |*                                                                 *|
  37 |* DATABASE_NAME - name of the database the function accesses      *|
  38 |*                 (e.g., host, services, ...)                     *|
  39 |*                                                                 *|
  40 |* ADD_PARAMS    - additional parameter, can vary in number        *|
  41 |*                                                                 *|
  42 |* ADD_VARIABLES - names of additional parameter                   *|
  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 |* NEED__RES     - the global _res variable might be used so we    *|
  50 |*                 will have to initialize it if necessary         *|
  51 |*                                                                 *|
  52 |* PREPROCESS    - code run before anything else                   *|
  53 |*                                                                 *|
  54 |* POSTPROCESS   - code run after the lookup                       *|
  55 |*                                                                 *|
  56 \*******************************************************************/
  57
  58 /* To make the real sources a bit prettier.  */
  59 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
  60 #define APPEND_R(name) APPEND_R1 (name)
  61 #define APPEND_R1(name) name##_r
  62 #define INTERNAL(name) INTERNAL1 (name)
  63 #define INTERNAL1(name) __##name
  64
  65 #ifdef USE_NSCD
  66 # define NSCD_NAME ADD_NSCD (REENTRANT_NAME)
  67 # define ADD_NSCD(name) ADD_NSCD1 (name)
  68 # define ADD_NSCD1(name) __nscd_##name
  69 # define NOT_USENSCD_NAME ADD_NOT_NSCDUSE (DATABASE_NAME)
  70 # define ADD_NOT_NSCDUSE(name) ADD_NOT_NSCDUSE1 (name)
  71 # define ADD_NOT_NSCDUSE1(name) __nss_not_use_nscd_##name
  72 #endif
  73
  74 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  75 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  76 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  77 #define STRINGIZE(name) STRINGIZE1 (name)
  78 #define STRINGIZE1(name) #name
  79
  80 #define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  81 #define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  82 #define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  83
  84 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  85 #ifdef NEED_H_ERRNO
  86 # define H_ERRNO_PARM , int *h_errnop
  87 # define H_ERRNO_VAR , h_errnop
  88 #else
  89 # define H_ERRNO_PARM
  90 # define H_ERRNO_VAR
  91 #endif
  92
  93
  94 /* Type of the lookup function we need here.  */
  95 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
  96                                             size_t, int * H_ERRNO_PARM);
  97
  98 /* Some usages of this file might use this variable.  */
  99 extern struct __res_state _res;
 100
 101 /* The lookup function for the first entry of this service.  */
 102 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp);
 103
 104 /* Interval in which we transfer retry to contact the NSCD.  */
 105 #define NSS_NSCD_RETRY  100
 106
 107
 108 int
 109 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 110                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 111 {
 112   static service_user *startp;
 113   static lookup_function start_fct;
 114   service_user *nip;
 115   lookup_function fct;
 116   int no_more;
 117   enum nss_status status = NSS_STATUS_UNAVAIL;
 118 #ifdef USE_NSCD
 119   int nscd_status;
 120 #endif
 121
 122 #ifdef PREPROCESS
 123   PREPROCESS;
 124 #endif
 125
 126 #ifdef HANDLE_DIGITS_DOTS
 127   /* We have to test for the use of IPv6 which can only be done by
 128      examining `_res'.  */
 129   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 130     {
 131       *h_errnop = NETDB_INTERNAL;
 132       *result = NULL;
 133       return errno;
 134     }
 135 # define resbuf (*resbuf)
 136 # include "digits_dots.c"
 137 # undef resbuf
 138 #endif
 139
 140 #ifdef USE_NSCD
 141   if (NOT_USENSCD_NAME && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 142     NOT_USENSCD_NAME = 0;
 143
 144   if (!NOT_USENSCD_NAME)
 145     {
 146       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen
 147                                H_ERRNO_VAR);
 148       if (nscd_status >= 0)
 149         {
 150           *result = nscd_status == 0 ? resbuf : NULL;
 151           return nscd_status;
 152         }
 153     }
 154 #endif
 155
 156   if (startp == NULL)
 157     {
 158       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, (void **) &fct);
 159       if (no_more)
 160         startp = (service_user *) -1l;
 161       else
 162         {
 163           startp = nip;
 164           start_fct = fct;
 165
 166 #ifdef NEED__RES
 167           /* The resolver code will really be used so we have to
 168              initialize it.  */
 169           if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 170             {
 171               *h_errnop = NETDB_INTERNAL;
 172               *result = NULL;
 173               return errno;
 174             }
 175 #endif /* need _res */
 176 #ifdef NEED__RES_HCONF
 177           if (!_res_hconf.initialized)
 178             _res_hconf_init ();
 179 #endif /* need _res_hconf */
 180         }
 181     }
 182   else
 183     {
 184       fct = start_fct;
 185       no_more = (nip = startp) == (service_user *) -1l;
 186     }
 187
 188   while (no_more == 0)
 189     {
 190       status = DL_CALL_FCT (fct, (ADD_VARIABLES, resbuf, buffer, buflen,
 191                                    &errno H_ERRNO_VAR));
 192
 193       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 194          provided buffer is too small.  In this case we should give
 195          the user the possibility to enlarge the buffer and we should
 196          not simply go on with the next service (even if the TRYAGAIN
 197          action tells us so).  */
 198       if (status == NSS_STATUS_TRYAGAIN
 199 #ifdef NEED_H_ERRNO
 200           && *h_errnop == NETDB_INTERNAL
 201 #endif
 202           && errno == ERANGE)
 203         break;
 204
 205       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 206                             (void **) &fct, status, 0);
 207     }
 208
 209 #ifdef HANDLE_DIGITS_DOTS
 210 done:
 211 #endif
 212   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 213 #ifdef POSTPROCESS
 214   POSTPROCESS;
 215 #endif
 216   return status == NSS_STATUS_SUCCESS ? 0 : errno;
 217 }
 218
 219 #if defined SHARED && DO_VERSIONING
 220 #define OLD(name) OLD1 (name)
 221 #define OLD1(name) __old_##name
 222
 223 int
 224 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 225                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 226 {
 227   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 228                                        buflen, result H_ERRNO_VAR);
 229
 230   if (ret != 0)
 231     ret = -1;
 232
 233   return ret;
 234 }
 235
 236 #define do_symbol_version(real, name, version) \
 237   symbol_version(real, name, version)
 238 do_symbol_version(OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2.0);
 239
 240 #define do_default_symbol_version(real, name, version) \
 241   default_symbol_version(real, name, version)
 242 do_default_symbol_version(INTERNAL (REENTRANT_NAME), REENTRANT_NAME,
 243                           GLIBC_2.1.2);
 244 #else
 245 #define do_weak_alias(n1, n2) weak_alias (n1, (n2))
 246 do_weak_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME)
 247 #endif