nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996-2002, 2003, 2004, 2006 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 <atomic.h>
  22 #include <errno.h>
  23 #include <stdbool.h>
  24 #include "nsswitch.h"
  25 #ifdef USE_NSCD
  26 # include <nscd/nscd_proto.h>
  27 #endif
  28 #ifdef NEED__RES_HCONF
  29 # include <resolv/res_hconf.h>
  30 #endif
  31 #ifdef NEED__RES
  32 # include <resolv.h>
  33 #endif
  34 /*******************************************************************\
  35 |* Here we assume several symbols to be defined:                   *|
  36 |*                                                                 *|
  37 |* LOOKUP_TYPE   - the return type of the function                 *|
  38 |*                                                                 *|
  39 |* FUNCTION_NAME - name of the non-reentrant function              *|
  40 |*                                                                 *|
  41 |* DATABASE_NAME - name of the database the function accesses      *|
  42 |*                 (e.g., host, services, ...)                     *|
  43 |*                                                                 *|
  44 |* ADD_PARAMS    - additional parameter, can vary in number        *|
  45 |*                                                                 *|
  46 |* ADD_VARIABLES - names of additional parameter                   *|
  47 |*                                                                 *|
  48 |* Optionally the following vars can be defined:                   *|
  49 |*                                                                 *|
  50 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  51 |*                 the global `h_errno' variable.                  *|
  52 |*                                                                 *|
  53 |* NEED__RES     - the global _res variable might be used so we    *|
  54 |*                 will have to initialize it if necessary         *|
  55 |*                                                                 *|
  56 |* PREPROCESS    - code run before anything else                   *|
  57 |*                                                                 *|
  58 |* POSTPROCESS   - code run after the lookup                       *|
  59 |*                                                                 *|
  60 \*******************************************************************/
  61
  62 /* To make the real sources a bit prettier.  */
  63 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
  64 #define APPEND_R(name) APPEND_R1 (name)
  65 #define APPEND_R1(name) name##_r
  66 #define INTERNAL(name) INTERNAL1 (name)
  67 #define INTERNAL1(name) __##name
  68 #define NEW(name) NEW1 (name)
  69 #define NEW1(name) __new_##name
  70
  71 #ifdef USE_NSCD
  72 # define NSCD_NAME ADD_NSCD (REENTRANT_NAME)
  73 # define ADD_NSCD(name) ADD_NSCD1 (name)
  74 # define ADD_NSCD1(name) __nscd_##name
  75 # define NOT_USENSCD_NAME ADD_NOT_NSCDUSE (DATABASE_NAME)
  76 # define ADD_NOT_NSCDUSE(name) ADD_NOT_NSCDUSE1 (name)
  77 # define ADD_NOT_NSCDUSE1(name) __nss_not_use_nscd_##name
  78 #endif
  79
  80 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  81 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  82 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  83 #define STRINGIZE(name) STRINGIZE1 (name)
  84 #define STRINGIZE1(name) #name
  85
  86 #ifndef DB_LOOKUP_FCT
  87 # define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  88 # define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  89 # define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  90 #endif
  91
  92 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  93 #ifdef NEED_H_ERRNO
  94 # define H_ERRNO_PARM , int *h_errnop
  95 # define H_ERRNO_VAR , h_errnop
  96 # define H_ERRNO_VAR_P h_errnop
  97 #else
  98 # define H_ERRNO_PARM
  99 # define H_ERRNO_VAR
 100 # define H_ERRNO_VAR_P NULL
 101 #endif
 102
 103 #ifdef HAVE_AF
 104 # define AF_VAL af
 105 #else
 106 # define AF_VAL AF_INET
 107 #endif
 108
 109 /* Type of the lookup function we need here.  */
 110 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
 111                                             size_t, int * H_ERRNO_PARM);
 112
 113 /* The lookup function for the first entry of this service.  */
 114 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp)
 115      internal_function;
 116 libc_hidden_proto (DB_LOOKUP_FCT)
 117
 118
 119 int
 120 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 121                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 122 {
 123   static service_user *startp;
 124   static lookup_function start_fct;
 125   service_user *nip;
 126   union
 127   {
 128     lookup_function l;
 129     void *ptr;
 130   } fct;
 131
 132   int no_more;
 133   enum nss_status status = NSS_STATUS_UNAVAIL;
 134 #ifdef USE_NSCD
 135   int nscd_status;
 136 #endif
 137 #ifdef NEED_H_ERRNO
 138   bool any_service = false;
 139 #endif
 140
 141 #ifdef PREPROCESS
 142   PREPROCESS;
 143 #endif
 144
 145 #ifdef HANDLE_DIGITS_DOTS
 146   switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
 147                                       buflen, result, &status, AF_VAL,
 148                                       H_ERRNO_VAR_P))
 149     {
 150     case -1:
 151       return errno;
 152     case 1:
 153       goto done;
 154     }
 155 #endif
 156
 157 #ifdef USE_NSCD
 158   if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 159     NOT_USENSCD_NAME = 0;
 160
 161   if (!NOT_USENSCD_NAME)
 162     {
 163       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen, result
 164                                H_ERRNO_VAR);
 165       if (nscd_status >= 0)
 166         return nscd_status;
 167     }
 168 #endif
 169
 170   if (startp == NULL)
 171     {
 172       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, &fct.ptr);
 173       if (no_more)
 174         startp = (service_user *) -1l;
 175       else
 176         {
 177 #ifdef NEED__RES
 178           /* The resolver code will really be used so we have to
 179              initialize it.  */
 180           if (__res_maybe_init (&_res, 0) == -1)
 181             {
 182               *h_errnop = NETDB_INTERNAL;
 183               *result = NULL;
 184               return errno;
 185             }
 186 #endif /* need _res */
 187 #ifdef NEED__RES_HCONF
 188           if (!_res_hconf.initialized)
 189             _res_hconf_init ();
 190 #endif /* need _res_hconf */
 191
 192           start_fct = fct.l;
 193           /* Make sure start_fct is written before startp.  */
 194           atomic_write_barrier ();
 195           startp = nip;
 196         }
 197     }
 198   else
 199     {
 200       fct.l = start_fct;
 201       no_more = (nip = startp) == (service_user *) -1l;
 202     }
 203
 204   while (no_more == 0)
 205     {
 206 #ifdef NEED_H_ERRNO
 207       any_service = true;
 208 #endif
 209
 210       status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
 211                                     &errno H_ERRNO_VAR));
 212
 213       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 214          provided buffer is too small.  In this case we should give
 215          the user the possibility to enlarge the buffer and we should
 216          not simply go on with the next service (even if the TRYAGAIN
 217          action tells us so).  */
 218       if (status == NSS_STATUS_TRYAGAIN
 219 #ifdef NEED_H_ERRNO
 220           && *h_errnop == NETDB_INTERNAL
 221 #endif
 222           && errno == ERANGE)
 223         break;
 224
 225       no_more = __nss_next (&nip, REENTRANT_NAME_STRING,
 226                             &fct.ptr, status, 0);
 227     }
 228
 229 #ifdef HANDLE_DIGITS_DOTS
 230 done:
 231 #endif
 232   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 233 #ifdef NEED_H_ERRNO
 234   if (status != NSS_STATUS_SUCCESS && ! any_service)
 235     /* We were not able to use any service.  */
 236     *h_errnop = NO_RECOVERY;
 237 #endif
 238 #ifdef POSTPROCESS
 239   POSTPROCESS;
 240 #endif
 241
 242   int res;
 243   if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND)
 244     res = 0;
 245   /* Don't pass back ERANGE if this is not for a too-small buffer.  */
 246   else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN)
 247     res = EINVAL;
 248 #ifdef NEED_H_ERRNO
 249   /* These functions only set errno if h_errno is NETDB_INTERNAL.  */
 250   else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL)
 251     res = EAGAIN;
 252 #endif
 253   else
 254     return errno;
 255
 256   __set_errno (res);
 257   return res;
 258 }
 259
 260
 261 #include <shlib-compat.h>
 262 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 263 #define OLD(name) OLD1 (name)
 264 #define OLD1(name) __old_##name
 265
 266 int
 267 attribute_compat_text_section
 268 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 269                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 270 {
 271   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 272                                        buflen, result H_ERRNO_VAR);
 273
 274   if (ret != 0 || result == NULL)
 275     ret = -1;
 276
 277   return ret;
 278 }
 279
 280 #define do_symbol_version(real, name, version) \
 281   compat_symbol (libc, real, name, version)
 282 do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
 283 #endif
 284
 285 /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
 286    in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
 287    hidden too.  */
 288 strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
 289
 290 #define do_default_symbol_version(real, name, version) \
 291   versioned_symbol (libc, real, name, version)
 292 do_default_symbol_version (NEW (REENTRANT_NAME),
 293                            REENTRANT_NAME, GLIBC_2_1_2);
 294
 295 static_link_warning (REENTRANT_NAME)