nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996,97,98,99,2000,2001,2002 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <stdbool.h>
  23 #include "nsswitch.h"
  24 #ifdef USE_NSCD
  25 # include <nscd/nscd_proto.h>
  26 #endif
  27 #ifdef NEED__RES_HCONF
  28 # include <resolv/res_hconf.h>
  29 #endif
  30 #ifdef NEED__RES
  31 # include <resolv.h>
  32 #endif
  33 /*******************************************************************\
  34 |* Here we assume several symbols to be defined:                   *|
  35 |*                                                                 *|
  36 |* LOOKUP_TYPE   - the return type of the function                 *|
  37 |*                                                                 *|
  38 |* FUNCTION_NAME - name of the non-reentrant function              *|
  39 |*                                                                 *|
  40 |* DATABASE_NAME - name of the database the function accesses      *|
  41 |*                 (e.g., host, services, ...)                     *|
  42 |*                                                                 *|
  43 |* ADD_PARAMS    - additional parameter, can vary in number        *|
  44 |*                                                                 *|
  45 |* ADD_VARIABLES - names of additional parameter                   *|
  46 |*                                                                 *|
  47 |* Optionally the following vars can be defined:                   *|
  48 |*                                                                 *|
  49 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  50 |*                 the global `h_errno' variable.                  *|
  51 |*                                                                 *|
  52 |* NEED__RES     - the global _res variable might be used so we    *|
  53 |*                 will have to initialize it if necessary         *|
  54 |*                                                                 *|
  55 |* PREPROCESS    - code run before anything else                   *|
  56 |*                                                                 *|
  57 |* POSTPROCESS   - code run after the lookup                       *|
  58 |*                                                                 *|
  59 \*******************************************************************/
  60
  61 /* To make the real sources a bit prettier.  */
  62 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
  63 #define APPEND_R(name) APPEND_R1 (name)
  64 #define APPEND_R1(name) name##_r
  65 #define INTERNAL(name) INTERNAL1 (name)
  66 #define INTERNAL1(name) __##name
  67 #define NEW(name) NEW1 (name)
  68 #define NEW1(name) __new_##name
  69
  70 #ifdef USE_NSCD
  71 # define NSCD_NAME ADD_NSCD (REENTRANT_NAME)
  72 # define ADD_NSCD(name) ADD_NSCD1 (name)
  73 # define ADD_NSCD1(name) __nscd_##name
  74 # define NOT_USENSCD_NAME ADD_NOT_NSCDUSE (DATABASE_NAME)
  75 # define ADD_NOT_NSCDUSE(name) ADD_NOT_NSCDUSE1 (name)
  76 # define ADD_NOT_NSCDUSE1(name) __nss_not_use_nscd_##name
  77 #endif
  78
  79 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  80 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  81 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  82 #define STRINGIZE(name) STRINGIZE1 (name)
  83 #define STRINGIZE1(name) #name
  84
  85 #ifndef DB_LOOKUP_FCT
  86 # define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  87 # define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  88 # define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  89 #endif
  90
  91 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  92 #ifdef NEED_H_ERRNO
  93 # define H_ERRNO_PARM , int *h_errnop
  94 # define H_ERRNO_VAR , h_errnop
  95 # define H_ERRNO_VAR_P h_errnop
  96 #else
  97 # define H_ERRNO_PARM
  98 # define H_ERRNO_VAR
  99 # define H_ERRNO_VAR_P NULL
 100 #endif
 101
 102 #ifndef HAVE_TYPE
 103 # define TYPE_VAR_P NULL
 104 # define FLAGS_VAR 0
 105 #endif
 106
 107 #ifdef HAVE_AF
 108 # define AF_VAR_P &af
 109 #else
 110 # define AF_VAR_P NULL
 111 #endif
 112
 113 /* Type of the lookup function we need here.  */
 114 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
 115                                             size_t, int * H_ERRNO_PARM);
 116
 117 /* The lookup function for the first entry of this service.  */
 118 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp)
 119      internal_function;
 120 libc_hidden_proto (DB_LOOKUP_FCT)
 121
 122 /* Interval in which we transfer retry to contact the NSCD.  */
 123 #define NSS_NSCD_RETRY  100
 124
 125
 126 int
 127 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 128                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 129 {
 130   static service_user *startp;
 131   static lookup_function start_fct;
 132   service_user *nip;
 133   lookup_function fct;
 134   int no_more;
 135   enum nss_status status = NSS_STATUS_UNAVAIL;
 136 #ifdef USE_NSCD
 137   int nscd_status;
 138 #endif
 139 #ifdef NEED_H_ERRNO
 140   bool any_service = false;
 141 #endif
 142
 143 #ifdef PREPROCESS
 144   PREPROCESS;
 145 #endif
 146
 147 #ifdef HANDLE_DIGITS_DOTS
 148   switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
 149                                       buflen, result, &status,
 150                                       TYPE_VAR_P, FLAGS_VAR, AF_VAR_P,
 151                                       H_ERRNO_VAR_P))
 152     {
 153     case -1:
 154       return errno;
 155     case 1:
 156       goto done;
 157     }
 158 #endif
 159
 160 #ifdef USE_NSCD
 161   if (NOT_USENSCD_NAME && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 162     NOT_USENSCD_NAME = 0;
 163
 164   if (!NOT_USENSCD_NAME)
 165     {
 166       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen
 167                                H_ERRNO_VAR);
 168       if (nscd_status >= 0)
 169         {
 170           *result = nscd_status == 0 ? resbuf : NULL;
 171           return nscd_status;
 172         }
 173     }
 174 #endif
 175
 176   if (startp == NULL)
 177     {
 178       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, (void **) &fct);
 179       if (no_more)
 180         startp = (service_user *) -1l;
 181       else
 182         {
 183           startp = nip;
 184           start_fct = fct;
 185
 186 #ifdef NEED__RES
 187           /* The resolver code will really be used so we have to
 188              initialize it.  */
 189           if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
 190             {
 191               *h_errnop = NETDB_INTERNAL;
 192               *result = NULL;
 193               return errno;
 194             }
 195 #endif /* need _res */
 196 #ifdef NEED__RES_HCONF
 197           if (!_res_hconf.initialized)
 198             _res_hconf_init ();
 199 #endif /* need _res_hconf */
 200         }
 201     }
 202   else
 203     {
 204       fct = start_fct;
 205       no_more = (nip = startp) == (service_user *) -1l;
 206     }
 207
 208   while (no_more == 0)
 209     {
 210 #ifdef NEED_H_ERRNO
 211       any_service = true;
 212 #endif
 213
 214       status = DL_CALL_FCT (fct, (ADD_VARIABLES, resbuf, buffer, buflen,
 215                                    &errno H_ERRNO_VAR));
 216
 217       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 218          provided buffer is too small.  In this case we should give
 219          the user the possibility to enlarge the buffer and we should
 220          not simply go on with the next service (even if the TRYAGAIN
 221          action tells us so).  */
 222       if (status == NSS_STATUS_TRYAGAIN
 223 #ifdef NEED_H_ERRNO
 224           && *h_errnop == NETDB_INTERNAL
 225 #endif
 226           && errno == ERANGE)
 227         break;
 228
 229       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 230                             (void **) &fct, status, 0);
 231     }
 232
 233 #ifdef HANDLE_DIGITS_DOTS
 234 done:
 235 #endif
 236   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 237 #ifdef NEED_H_ERRNO
 238   if (status != NSS_STATUS_SUCCESS && ! any_service)
 239     /* We were not able to use any service.  */
 240     *h_errnop = NO_RECOVERY;
 241 #endif
 242 #ifdef POSTPROCESS
 243   POSTPROCESS;
 244 #endif
 245   return (status == NSS_STATUS_SUCCESS
 246           ? 0 : (status == NSS_STATUS_TRYAGAIN ? EAGAIN : ENOENT));
 247 }
 248
 249
 250 #include <shlib-compat.h>
 251 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 252 #define OLD(name) OLD1 (name)
 253 #define OLD1(name) __old_##name
 254
 255 int
 256 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 257                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 258 {
 259   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 260                                        buflen, result H_ERRNO_VAR);
 261
 262   if (ret != 0)
 263     ret = -1;
 264
 265   return ret;
 266 }
 267
 268 #define do_symbol_version(real, name, version) \
 269   compat_symbol (libc, real, name, version)
 270 do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
 271 #endif
 272
 273 /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
 274    in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
 275    hidden too.  */
 276 strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
 277
 278 #define do_default_symbol_version(real, name, version) \
 279   versioned_symbol (libc, real, name, version)
 280 do_default_symbol_version (NEW (REENTRANT_NAME),
 281                            REENTRANT_NAME, GLIBC_2_1_2);