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   /* We have to test for the use of IPv6 which can only be done by
 119      examining `_res'.  */
 120   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 121     {
 122       *h_errnop = NETDB_INTERNAL;
 123       *result = NULL;
 124       return -1;
 125     }
 126 # define resbuf (*resbuf)
 127 # include "digits_dots.c"
 128 # undef resbuf
 129 #endif
 130
 131 #ifdef USE_NSCD
 132   if (NOT_USENSCD_NAME && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 133     NOT_USENSCD_NAME = 0;
 134
 135   if (!NOT_USENSCD_NAME)
 136     {
 137       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen
 138                                H_ERRNO_VAR);
 139       if (nscd_status < 1)
 140         {
 141           *result = nscd_status == 0 ? resbuf : NULL;
 142           return nscd_status;
 143         }
 144     }
 145 #endif
 146
 147   if (startp == NULL)
 148     {
 149       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, (void **) &fct);
 150       if (no_more)
 151         startp = (service_user *) -1l;
 152       else
 153         {
 154           startp = nip;
 155           start_fct = fct;
 156
 157 #ifdef NEED__RES
 158           /* The resolver code will really be used so we have to
 159              initialize it.  */
 160           if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 161             {
 162               *h_errnop = NETDB_INTERNAL;
 163               *result = NULL;
 164               return -1;
 165             }
 166 #endif /* need _res */
 167 #ifdef NEED__RES_HCONF
 168           if (!_res_hconf.initialized)
 169             _res_hconf_init ();
 170 #endif /* need _res_hconf */
 171         }
 172     }
 173   else
 174     {
 175       fct = start_fct;
 176       no_more = (nip = startp) == (service_user *) -1l;
 177     }
 178
 179   while (no_more == 0)
 180     {
 181       status = _CALL_DL_FCT (fct, (ADD_VARIABLES, resbuf, buffer, buflen,
 182                                    &errno H_ERRNO_VAR));
 183
 184       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 185          provided buffer is too small.  In this case we should give
 186          the user the possibility to enlarge the buffer and we should
 187          not simply go on with the next service (even if the TRYAGAIN
 188          action tells us so).  */
 189       if (status == NSS_STATUS_TRYAGAIN
 190 #ifdef NEED_H_ERRNO
 191           && *h_errnop == NETDB_INTERNAL
 192 #endif
 193           && errno == ERANGE)
 194         break;
 195
 196       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 197                             (void **) &fct, status, 0);
 198     }
 199
 200 #ifdef HANDLE_DIGITS_DOTS
 201 done:
 202 #endif
 203   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 204 #ifdef POSTPROCESS
 205   POSTPROCESS;
 206 #endif
 207   return status == NSS_STATUS_SUCCESS ? 0 : -1;
 208 }
 209
 210 #define do_weak_alias(n1, n2) weak_alias (n1, (n2))
 211 do_weak_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME)