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