nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996-2004, 2006, 2007 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 #include "sysdep.h"
  26 #ifdef USE_NSCD
  27 # include <nscd/nscd_proto.h>
  28 #endif
  29 #ifdef NEED__RES_HCONF
  30 # include <resolv/res_hconf.h>
  31 #endif
  32 #ifdef NEED__RES
  33 # include <resolv.h>
  34 #endif
  35 /*******************************************************************\
  36 |* Here we assume several symbols to be defined:                   *|
  37 |*                                                                 *|
  38 |* LOOKUP_TYPE   - the return type of the function                 *|
  39 |*                                                                 *|
  40 |* FUNCTION_NAME - name of the non-reentrant function              *|
  41 |*                                                                 *|
  42 |* DATABASE_NAME - name of the database the function accesses      *|
  43 |*                 (e.g., host, services, ...)                     *|
  44 |*                                                                 *|
  45 |* ADD_PARAMS    - additional parameters, can vary in number       *|
  46 |*                                                                 *|
  47 |* ADD_VARIABLES - names of additional parameters                  *|
  48 |*                                                                 *|
  49 |* Optionally the following vars can be defined:                   *|
  50 |*                                                                 *|
  51 |* EXTRA_PARAMS  - optional parameters, can vary in number         *|
  52 |*                                                                 *|
  53 |* EXTRA_VARIABLES - names of optional parameter                   *|
  54 |*                                                                 *|
  55 |* FUNCTION_NAME - alternative name of the non-reentrant function  *|
  56 |*                                                                 *|
  57 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  58 |*                 the global `h_errno' variable.                  *|
  59 |*                                                                 *|
  60 |* NEED__RES     - the global _res variable might be used so we    *|
  61 |*                 will have to initialize it if necessary         *|
  62 |*                                                                 *|
  63 |* PREPROCESS    - code run before anything else                   *|
  64 |*                                                                 *|
  65 |* POSTPROCESS   - code run after the lookup                       *|
  66 |*                                                                 *|
  67 \*******************************************************************/
  68
  69 /* To make the real sources a bit prettier.  */
  70 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
  71 #ifdef FUNCTION2_NAME
  72 # define REENTRANT2_NAME APPEND_R (FUNCTION2_NAME)
  73 #else
  74 # define REENTRANT2_NAME NULL
  75 #endif
  76 #define APPEND_R(name) APPEND_R1 (name)
  77 #define APPEND_R1(name) name##_r
  78 #define INTERNAL(name) INTERNAL1 (name)
  79 #define INTERNAL1(name) __##name
  80 #define NEW(name) NEW1 (name)
  81 #define NEW1(name) __new_##name
  82
  83 #ifdef USE_NSCD
  84 # define NSCD_NAME ADD_NSCD (REENTRANT_NAME)
  85 # define ADD_NSCD(name) ADD_NSCD1 (name)
  86 # define ADD_NSCD1(name) __nscd_##name
  87 # define NOT_USENSCD_NAME ADD_NOT_NSCDUSE (DATABASE_NAME)
  88 # define ADD_NOT_NSCDUSE(name) ADD_NOT_NSCDUSE1 (name)
  89 # define ADD_NOT_NSCDUSE1(name) __nss_not_use_nscd_##name
  90 #endif
  91
  92 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  93 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  94 #ifdef FUNCTION2_NAME
  95 # define REENTRANT2_NAME_STRING STRINGIZE (REENTRANT2_NAME)
  96 #else
  97 # define REENTRANT2_NAME_STRING NULL
  98 #endif
  99 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
 100 #define STRINGIZE(name) STRINGIZE1 (name)
 101 #define STRINGIZE1(name) #name
 102
 103 #ifndef DB_LOOKUP_FCT
 104 # define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup2)
 105 # define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
 106 # define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
 107 #endif
 108
 109 /* Sometimes we need to store error codes in the `h_errno' variable.  */
 110 #ifdef NEED_H_ERRNO
 111 # define H_ERRNO_PARM , int *h_errnop
 112 # define H_ERRNO_VAR , h_errnop
 113 # define H_ERRNO_VAR_P h_errnop
 114 #else
 115 # define H_ERRNO_PARM
 116 # define H_ERRNO_VAR
 117 # define H_ERRNO_VAR_P NULL
 118 #endif
 119
 120 #ifndef EXTRA_PARAMS
 121 # define EXTRA_PARAMS
 122 #endif
 123 #ifndef EXTRA_VARIABLES
 124 # define EXTRA_VARIABLES
 125 #endif
 126
 127 #ifdef HAVE_AF
 128 # define AF_VAL af
 129 #else
 130 # define AF_VAL AF_INET
 131 #endif
 132
 133 /* Type of the lookup function we need here.  */
 134 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
 135                                             size_t, int * H_ERRNO_PARM
 136                                             EXTRA_PARAMS);
 137
 138 /* The lookup function for the first entry of this service.  */
 139 extern int DB_LOOKUP_FCT (service_user **nip, const char *name,
 140                           const char *name2, void **fctp)
 141      internal_function;
 142 libc_hidden_proto (DB_LOOKUP_FCT)
 143
 144
 145 int
 146 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 147                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM
 148                            EXTRA_PARAMS)
 149 {
 150   static bool startp_initialized;
 151   static service_user *startp;
 152   static lookup_function start_fct;
 153   service_user *nip;
 154   union
 155   {
 156     lookup_function l;
 157     void *ptr;
 158   } fct;
 159
 160   int no_more;
 161   enum nss_status status = NSS_STATUS_UNAVAIL;
 162 #ifdef USE_NSCD
 163   int nscd_status;
 164 #endif
 165 #ifdef NEED_H_ERRNO
 166   bool any_service = false;
 167 #endif
 168
 169 #ifdef PREPROCESS
 170   PREPROCESS;
 171 #endif
 172
 173 #ifdef HANDLE_DIGITS_DOTS
 174   switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
 175                                       buflen, result, &status, AF_VAL,
 176                                       H_ERRNO_VAR_P))
 177     {
 178     case -1:
 179       return errno;
 180     case 1:
 181       goto done;
 182     }
 183 #endif
 184
 185 #ifdef USE_NSCD
 186   if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 187     NOT_USENSCD_NAME = 0;
 188
 189   if (!NOT_USENSCD_NAME)
 190     {
 191       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen, result
 192                                H_ERRNO_VAR);
 193       if (nscd_status >= 0)
 194         return nscd_status;
 195     }
 196 #endif
 197
 198   if (! startp_initialized)
 199     {
 200       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING,
 201                                REENTRANT2_NAME_STRING, &fct.ptr);
 202       if (no_more)
 203         {
 204           void *tmp_ptr = (service_user *) -1l;
 205           PTR_MANGLE (tmp_ptr);
 206           startp = tmp_ptr;
 207         }
 208       else
 209         {
 210 #ifdef NEED__RES
 211           /* The resolver code will really be used so we have to
 212              initialize it.  */
 213           if (__res_maybe_init (&_res, 0) == -1)
 214             {
 215               *h_errnop = NETDB_INTERNAL;
 216               *result = NULL;
 217               return errno;
 218             }
 219 #endif /* need _res */
 220 #ifdef NEED__RES_HCONF
 221           if (!_res_hconf.initialized)
 222             _res_hconf_init ();
 223 #endif /* need _res_hconf */
 224
 225           void *tmp_ptr = fct.l;
 226           PTR_MANGLE (tmp_ptr);
 227           start_fct = tmp_ptr;
 228           tmp_ptr = nip;
 229           PTR_MANGLE (tmp_ptr);
 230           startp = tmp_ptr;
 231         }
 232
 233       /* Make sure start_fct and startp are written before
 234          startp_initialized.  */
 235       atomic_write_barrier ();
 236       startp_initialized = true;
 237     }
 238   else
 239     {
 240       fct.l = start_fct;
 241       PTR_DEMANGLE (fct.l);
 242       nip = startp;
 243       PTR_DEMANGLE (nip);
 244       no_more = nip == (service_user *) -1l;
 245     }
 246
 247   while (no_more == 0)
 248     {
 249 #ifdef NEED_H_ERRNO
 250       any_service = true;
 251 #endif
 252
 253       status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
 254                                     &errno H_ERRNO_VAR EXTRA_VARIABLES));
 255
 256       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 257          provided buffer is too small.  In this case we should give
 258          the user the possibility to enlarge the buffer and we should
 259          not simply go on with the next service (even if the TRYAGAIN
 260          action tells us so).  */
 261       if (status == NSS_STATUS_TRYAGAIN
 262 #ifdef NEED_H_ERRNO
 263           && *h_errnop == NETDB_INTERNAL
 264 #endif
 265           && errno == ERANGE)
 266         break;
 267
 268       no_more = __nss_next2 (&nip, REENTRANT_NAME_STRING,
 269                              REENTRANT2_NAME_STRING, &fct.ptr, status, 0);
 270     }
 271
 272 #ifdef HANDLE_DIGITS_DOTS
 273 done:
 274 #endif
 275   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 276 #ifdef NEED_H_ERRNO
 277   if (status != NSS_STATUS_SUCCESS && ! any_service)
 278     /* We were not able to use any service.  */
 279     *h_errnop = NO_RECOVERY;
 280 #endif
 281 #ifdef POSTPROCESS
 282   POSTPROCESS;
 283 #endif
 284
 285   int res;
 286   if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND)
 287     res = 0;
 288   /* Don't pass back ERANGE if this is not for a too-small buffer.  */
 289   else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN)
 290     res = EINVAL;
 291 #ifdef NEED_H_ERRNO
 292   /* These functions only set errno if h_errno is NETDB_INTERNAL.  */
 293   else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL)
 294     res = EAGAIN;
 295 #endif
 296   else
 297     return errno;
 298
 299   __set_errno (res);
 300   return res;
 301 }
 302
 303
 304 #ifndef FUNCTION2_NAME
 305 # include <shlib-compat.h>
 306 # if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 307 #  define OLD(name) OLD1 (name)
 308 #  define OLD1(name) __old_##name
 309
 310 int
 311 attribute_compat_text_section
 312 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 313                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 314 {
 315   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 316                                        buflen, result H_ERRNO_VAR);
 317
 318   if (ret != 0 || result == NULL)
 319     ret = -1;
 320
 321   return ret;
 322 }
 323
 324 #  define do_symbol_version(real, name, version) \
 325   compat_symbol (libc, real, name, version)
 326 do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
 327 # endif
 328
 329 /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
 330    in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
 331    hidden too.  */
 332 strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
 333
 334 # define do_default_symbol_version(real, name, version) \
 335   versioned_symbol (libc, real, name, version)
 336 do_default_symbol_version (NEW (REENTRANT_NAME),
 337                            REENTRANT_NAME, GLIBC_2_1_2);
 338 #endif
 339
 340 static_link_warning (REENTRANT_NAME)