nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996-2002, 2003 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   union
 134   {
 135     lookup_function l;
 136     void *ptr;
 137   } fct;
 138
 139   int no_more;
 140   enum nss_status status = NSS_STATUS_UNAVAIL;
 141 #ifdef USE_NSCD
 142   int nscd_status;
 143 #endif
 144 #ifdef NEED_H_ERRNO
 145   bool any_service = false;
 146 #endif
 147
 148 #ifdef PREPROCESS
 149   PREPROCESS;
 150 #endif
 151
 152 #ifdef HANDLE_DIGITS_DOTS
 153   switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
 154                                       buflen, result, &status,
 155                                       TYPE_VAR_P, FLAGS_VAR, AF_VAR_P,
 156                                       H_ERRNO_VAR_P))
 157     {
 158     case -1:
 159       return errno;
 160     case 1:
 161       goto done;
 162     }
 163 #endif
 164
 165 #ifdef USE_NSCD
 166   if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 167     NOT_USENSCD_NAME = 0;
 168
 169   if (!NOT_USENSCD_NAME)
 170     {
 171       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen
 172                                H_ERRNO_VAR);
 173       if (nscd_status >= 0)
 174         {
 175           *result = nscd_status == 0 ? resbuf : NULL;
 176           return nscd_status;
 177         }
 178     }
 179 #endif
 180
 181   if (startp == NULL)
 182     {
 183       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, &fct.ptr);
 184       if (no_more)
 185         startp = (service_user *) -1l;
 186       else
 187         {
 188           startp = nip;
 189           start_fct = fct.l;
 190
 191 #ifdef NEED__RES
 192           /* The resolver code will really be used so we have to
 193              initialize it.  */
 194           if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
 195             {
 196               *h_errnop = NETDB_INTERNAL;
 197               *result = NULL;
 198               return errno;
 199             }
 200 #endif /* need _res */
 201 #ifdef NEED__RES_HCONF
 202           if (!_res_hconf.initialized)
 203             _res_hconf_init ();
 204 #endif /* need _res_hconf */
 205         }
 206     }
 207   else
 208     {
 209       fct.l = start_fct;
 210       no_more = (nip = startp) == (service_user *) -1l;
 211     }
 212
 213   while (no_more == 0)
 214     {
 215 #ifdef NEED_H_ERRNO
 216       any_service = true;
 217 #endif
 218
 219       status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
 220                                     &errno H_ERRNO_VAR));
 221
 222       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 223          provided buffer is too small.  In this case we should give
 224          the user the possibility to enlarge the buffer and we should
 225          not simply go on with the next service (even if the TRYAGAIN
 226          action tells us so).  */
 227       if (status == NSS_STATUS_TRYAGAIN
 228 #ifdef NEED_H_ERRNO
 229           && *h_errnop == NETDB_INTERNAL
 230 #endif
 231           && errno == ERANGE)
 232         break;
 233
 234       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 235                             &fct.ptr, status, 0);
 236     }
 237
 238 #ifdef HANDLE_DIGITS_DOTS
 239 done:
 240 #endif
 241   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 242 #ifdef NEED_H_ERRNO
 243   if (status != NSS_STATUS_SUCCESS && ! any_service)
 244     /* We were not able to use any service.  */
 245     *h_errnop = NO_RECOVERY;
 246 #endif
 247 #ifdef POSTPROCESS
 248   POSTPROCESS;
 249 #endif
 250   return (status != NSS_STATUS_TRYAGAIN ? 0
 251 #ifdef NEED_H_ERRNO
 252           /* These functions only set errno if h_errno is NETDB_INTERNAL.  */
 253           : *h_errnop != NETDB_INTERNAL ? EAGAIN
 254 #endif
 255           : errno);
 256 }
 257
 258
 259 #include <shlib-compat.h>
 260 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 261 #define OLD(name) OLD1 (name)
 262 #define OLD1(name) __old_##name
 263
 264 int
 265 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 266                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 267 {
 268   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 269                                        buflen, result H_ERRNO_VAR);
 270
 271   if (ret != 0 || result == NULL)
 272     ret = -1;
 273
 274   return ret;
 275 }
 276
 277 #define do_symbol_version(real, name, version) \
 278   compat_symbol (libc, real, name, version)
 279 do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
 280 #endif
 281
 282 /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
 283    in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
 284    hidden too.  */
 285 strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
 286
 287 #define do_default_symbol_version(real, name, version) \
 288   versioned_symbol (libc, real, name, version)
 289 do_default_symbol_version (NEW (REENTRANT_NAME),
 290                            REENTRANT_NAME, GLIBC_2_1_2);