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