nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996-2002, 2003, 2004 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, result
 172                                H_ERRNO_VAR);
 173       if (nscd_status >= 0)
 174         return nscd_status;
 175     }
 176 #endif
 177
 178   if (startp == NULL)
 179     {
 180       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, &fct.ptr);
 181       if (no_more)
 182         startp = (service_user *) -1l;
 183       else
 184         {
 185           startp = nip;
 186           start_fct = fct.l;
 187
 188 #ifdef NEED__RES
 189           /* The resolver code will really be used so we have to
 190              initialize it.  */
 191           if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
 192             {
 193               *h_errnop = NETDB_INTERNAL;
 194               *result = NULL;
 195               return errno;
 196             }
 197 #endif /* need _res */
 198 #ifdef NEED__RES_HCONF
 199           if (!_res_hconf.initialized)
 200             _res_hconf_init ();
 201 #endif /* need _res_hconf */
 202         }
 203     }
 204   else
 205     {
 206       fct.l = start_fct;
 207       no_more = (nip = startp) == (service_user *) -1l;
 208     }
 209
 210   while (no_more == 0)
 211     {
 212 #ifdef NEED_H_ERRNO
 213       any_service = true;
 214 #endif
 215
 216       status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
 217                                     &errno H_ERRNO_VAR));
 218
 219       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 220          provided buffer is too small.  In this case we should give
 221          the user the possibility to enlarge the buffer and we should
 222          not simply go on with the next service (even if the TRYAGAIN
 223          action tells us so).  */
 224       if (status == NSS_STATUS_TRYAGAIN
 225 #ifdef NEED_H_ERRNO
 226           && *h_errnop == NETDB_INTERNAL
 227 #endif
 228           && errno == ERANGE)
 229         break;
 230
 231       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 232                             &fct.ptr, status, 0);
 233     }
 234
 235 #ifdef HANDLE_DIGITS_DOTS
 236 done:
 237 #endif
 238   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 239 #ifdef NEED_H_ERRNO
 240   if (status != NSS_STATUS_SUCCESS && ! any_service)
 241     /* We were not able to use any service.  */
 242     *h_errnop = NO_RECOVERY;
 243 #endif
 244 #ifdef POSTPROCESS
 245   POSTPROCESS;
 246 #endif
 247
 248   int res;
 249   if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND)
 250     res = 0;
 251   /* Don't pass back ERANGE if this is not for a too-small buffer.  */
 252   else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN)
 253     res = EINVAL;
 254 #ifdef NEED_H_ERRNO
 255   /* These functions only set errno if h_errno is NETDB_INTERNAL.  */
 256   else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL)
 257     res = EAGAIN;
 258 #endif
 259   else
 260     return errno;
 261
 262   __set_errno (res);
 263   return res;
 264 }
 265
 266
 267 #include <shlib-compat.h>
 268 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 269 #define OLD(name) OLD1 (name)
 270 #define OLD1(name) __old_##name
 271
 272 int
 273 attribute_compat_text_section
 274 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 275                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 276 {
 277   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 278                                        buflen, result H_ERRNO_VAR);
 279
 280   if (ret != 0 || result == NULL)
 281     ret = -1;
 282
 283   return ret;
 284 }
 285
 286 #define do_symbol_version(real, name, version) \
 287   compat_symbol (libc, real, name, version)
 288 do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
 289 #endif
 290
 291 /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
 292    in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
 293    hidden too.  */
 294 strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
 295
 296 #define do_default_symbol_version(real, name, version) \
 297   versioned_symbol (libc, real, name, version)
 298 do_default_symbol_version (NEW (REENTRANT_NAME),
 299                            REENTRANT_NAME, GLIBC_2_1_2);
 300
 301 static_link_warning (REENTRANT_NAME)