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 #ifdef HAVE_AF
 103 # define AF_VAL af
 104 #else
 105 # define AF_VAL AF_INET
 106 #endif
 107
 108 /* Type of the lookup function we need here.  */
 109 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
 110                                             size_t, int * H_ERRNO_PARM);
 111
 112 /* The lookup function for the first entry of this service.  */
 113 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp)
 114      internal_function;
 115 libc_hidden_proto (DB_LOOKUP_FCT)
 116
 117
 118 int
 119 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 120                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 121 {
 122   static service_user *startp;
 123   static lookup_function start_fct;
 124   service_user *nip;
 125   union
 126   {
 127     lookup_function l;
 128     void *ptr;
 129   } fct;
 130
 131   int no_more;
 132   enum nss_status status = NSS_STATUS_UNAVAIL;
 133 #ifdef USE_NSCD
 134   int nscd_status;
 135 #endif
 136 #ifdef NEED_H_ERRNO
 137   bool any_service = false;
 138 #endif
 139
 140 #ifdef PREPROCESS
 141   PREPROCESS;
 142 #endif
 143
 144 #ifdef HANDLE_DIGITS_DOTS
 145   switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
 146                                       buflen, result, &status, AF_VAL,
 147                                       H_ERRNO_VAR_P))
 148     {
 149     case -1:
 150       return errno;
 151     case 1:
 152       goto done;
 153     }
 154 #endif
 155
 156 #ifdef USE_NSCD
 157   if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 158     NOT_USENSCD_NAME = 0;
 159
 160   if (!NOT_USENSCD_NAME)
 161     {
 162       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen, result
 163                                H_ERRNO_VAR);
 164       if (nscd_status >= 0)
 165         return nscd_status;
 166     }
 167 #endif
 168
 169   if (startp == NULL)
 170     {
 171       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, &fct.ptr);
 172       if (no_more)
 173         startp = (service_user *) -1l;
 174       else
 175         {
 176           startp = nip;
 177           start_fct = fct.l;
 178
 179 #ifdef NEED__RES
 180           /* The resolver code will really be used so we have to
 181              initialize it.  */
 182           if (__res_maybe_init (&_res, 0) == -1)
 183             {
 184               *h_errnop = NETDB_INTERNAL;
 185               *result = NULL;
 186               return errno;
 187             }
 188 #endif /* need _res */
 189 #ifdef NEED__RES_HCONF
 190           if (!_res_hconf.initialized)
 191             _res_hconf_init ();
 192 #endif /* need _res_hconf */
 193         }
 194     }
 195   else
 196     {
 197       fct.l = start_fct;
 198       no_more = (nip = startp) == (service_user *) -1l;
 199     }
 200
 201   while (no_more == 0)
 202     {
 203 #ifdef NEED_H_ERRNO
 204       any_service = true;
 205 #endif
 206
 207       status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
 208                                     &errno H_ERRNO_VAR));
 209
 210       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 211          provided buffer is too small.  In this case we should give
 212          the user the possibility to enlarge the buffer and we should
 213          not simply go on with the next service (even if the TRYAGAIN
 214          action tells us so).  */
 215       if (status == NSS_STATUS_TRYAGAIN
 216 #ifdef NEED_H_ERRNO
 217           && *h_errnop == NETDB_INTERNAL
 218 #endif
 219           && errno == ERANGE)
 220         break;
 221
 222       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 223                             &fct.ptr, status, 0);
 224     }
 225
 226 #ifdef HANDLE_DIGITS_DOTS
 227 done:
 228 #endif
 229   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 230 #ifdef NEED_H_ERRNO
 231   if (status != NSS_STATUS_SUCCESS && ! any_service)
 232     /* We were not able to use any service.  */
 233     *h_errnop = NO_RECOVERY;
 234 #endif
 235 #ifdef POSTPROCESS
 236   POSTPROCESS;
 237 #endif
 238
 239   int res;
 240   if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND)
 241     res = 0;
 242   /* Don't pass back ERANGE if this is not for a too-small buffer.  */
 243   else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN)
 244     res = EINVAL;
 245 #ifdef NEED_H_ERRNO
 246   /* These functions only set errno if h_errno is NETDB_INTERNAL.  */
 247   else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL)
 248     res = EAGAIN;
 249 #endif
 250   else
 251     return errno;
 252
 253   __set_errno (res);
 254   return res;
 255 }
 256
 257
 258 #include <shlib-compat.h>
 259 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 260 #define OLD(name) OLD1 (name)
 261 #define OLD1(name) __old_##name
 262
 263 int
 264 attribute_compat_text_section
 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);
 291
 292 static_link_warning (REENTRANT_NAME)