nss/getXXbyYY_r.c

   1 /* Copyright (C) 1996-2004,2006,2007,2009,2010 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 # define CONCAT2(arg1, arg2) CONCAT2_2 (arg1, arg2)
  91 # define CONCAT2_2(arg1, arg2) arg1##arg2
  92 #endif
  93
  94 #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME)
  95 #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME)
  96 #ifdef FUNCTION2_NAME
  97 # define REENTRANT2_NAME_STRING STRINGIZE (REENTRANT2_NAME)
  98 #else
  99 # define REENTRANT2_NAME_STRING NULL
 100 #endif
 101 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
 102 #define STRINGIZE(name) STRINGIZE1 (name)
 103 #define STRINGIZE1(name) #name
 104
 105 #ifndef DB_LOOKUP_FCT
 106 # define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup2)
 107 # define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
 108 # define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
 109 #endif
 110
 111 /* Sometimes we need to store error codes in the `h_errno' variable.  */
 112 #ifdef NEED_H_ERRNO
 113 # define H_ERRNO_PARM , int *h_errnop
 114 # define H_ERRNO_VAR , h_errnop
 115 # define H_ERRNO_VAR_P h_errnop
 116 #else
 117 # define H_ERRNO_PARM
 118 # define H_ERRNO_VAR
 119 # define H_ERRNO_VAR_P NULL
 120 #endif
 121
 122 #ifndef EXTRA_PARAMS
 123 # define EXTRA_PARAMS
 124 #endif
 125 #ifndef EXTRA_VARIABLES
 126 # define EXTRA_VARIABLES
 127 #endif
 128
 129 #ifdef HAVE_AF
 130 # define AF_VAL af
 131 #else
 132 # define AF_VAL AF_INET
 133 #endif
 134
 135 /* Type of the lookup function we need here.  */
 136 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
 137                                             size_t, int * H_ERRNO_PARM
 138                                             EXTRA_PARAMS);
 139
 140 /* The lookup function for the first entry of this service.  */
 141 extern int DB_LOOKUP_FCT (service_user **nip, const char *name,
 142                           const char *name2, void **fctp)
 143      internal_function;
 144 libc_hidden_proto (DB_LOOKUP_FCT)
 145
 146
 147 int
 148 INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 149                            size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM
 150                            EXTRA_PARAMS)
 151 {
 152   static bool startp_initialized;
 153   static service_user *startp;
 154   static lookup_function start_fct;
 155   service_user *nip;
 156   union
 157   {
 158     lookup_function l;
 159     void *ptr;
 160   } fct;
 161
 162   int no_more;
 163   enum nss_status status = NSS_STATUS_UNAVAIL;
 164 #ifdef USE_NSCD
 165   int nscd_status;
 166 #endif
 167 #ifdef NEED_H_ERRNO
 168   bool any_service = false;
 169 #endif
 170
 171 #ifdef PREPROCESS
 172   PREPROCESS;
 173 #endif
 174
 175 #ifdef HANDLE_DIGITS_DOTS
 176   switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
 177                                       buflen, result, &status, AF_VAL,
 178                                       H_ERRNO_VAR_P))
 179     {
 180     case -1:
 181       return errno;
 182     case 1:
 183       goto done;
 184     }
 185 #endif
 186
 187 #ifdef USE_NSCD
 188   if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
 189     NOT_USENSCD_NAME = 0;
 190
 191   if (!NOT_USENSCD_NAME
 192       && !__nss_database_custom[CONCAT2 (NSS_DBSIDX_, DATABASE_NAME)])
 193     {
 194       nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen, result
 195                                H_ERRNO_VAR);
 196       if (nscd_status >= 0)
 197         return nscd_status;
 198     }
 199 #endif
 200
 201   if (! startp_initialized)
 202     {
 203       no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING,
 204                                REENTRANT2_NAME_STRING, &fct.ptr);
 205       if (no_more)
 206         {
 207           void *tmp_ptr = (service_user *) -1l;
 208           PTR_MANGLE (tmp_ptr);
 209           startp = tmp_ptr;
 210         }
 211       else
 212         {
 213 #ifdef NEED__RES
 214           /* The resolver code will really be used so we have to
 215              initialize it.  */
 216           if (__res_maybe_init (&_res, 0) == -1)
 217             {
 218               *h_errnop = NETDB_INTERNAL;
 219               *result = NULL;
 220               return errno;
 221             }
 222 #endif /* need _res */
 223 #ifdef NEED__RES_HCONF
 224           if (!_res_hconf.initialized)
 225             _res_hconf_init ();
 226 #endif /* need _res_hconf */
 227
 228           void *tmp_ptr = fct.l;
 229           PTR_MANGLE (tmp_ptr);
 230           start_fct = tmp_ptr;
 231           tmp_ptr = nip;
 232           PTR_MANGLE (tmp_ptr);
 233           startp = tmp_ptr;
 234         }
 235
 236       /* Make sure start_fct and startp are written before
 237          startp_initialized.  */
 238       atomic_write_barrier ();
 239       startp_initialized = true;
 240     }
 241   else
 242     {
 243       fct.l = start_fct;
 244       PTR_DEMANGLE (fct.l);
 245       nip = startp;
 246       PTR_DEMANGLE (nip);
 247       no_more = nip == (service_user *) -1l;
 248     }
 249
 250   while (no_more == 0)
 251     {
 252 #ifdef NEED_H_ERRNO
 253       any_service = true;
 254 #endif
 255
 256       status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
 257                                     &errno H_ERRNO_VAR EXTRA_VARIABLES));
 258
 259       /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 260          provided buffer is too small.  In this case we should give
 261          the user the possibility to enlarge the buffer and we should
 262          not simply go on with the next service (even if the TRYAGAIN
 263          action tells us so).  */
 264       if (status == NSS_STATUS_TRYAGAIN
 265 #ifdef NEED_H_ERRNO
 266           && *h_errnop == NETDB_INTERNAL
 267 #endif
 268           && errno == ERANGE)
 269         break;
 270
 271       no_more = __nss_next2 (&nip, REENTRANT_NAME_STRING,
 272                              REENTRANT2_NAME_STRING, &fct.ptr, status, 0);
 273     }
 274
 275 #ifdef HANDLE_DIGITS_DOTS
 276 done:
 277 #endif
 278   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 279 #ifdef NEED_H_ERRNO
 280   if (status != NSS_STATUS_SUCCESS && ! any_service)
 281     /* We were not able to use any service.  */
 282     *h_errnop = NO_RECOVERY;
 283 #endif
 284 #ifdef POSTPROCESS
 285   POSTPROCESS;
 286 #endif
 287
 288   int res;
 289   if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND)
 290     res = 0;
 291   /* Don't pass back ERANGE if this is not for a too-small buffer.  */
 292   else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN)
 293     res = EINVAL;
 294 #ifdef NEED_H_ERRNO
 295   /* These functions only set errno if h_errno is NETDB_INTERNAL.  */
 296   else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL)
 297     res = EAGAIN;
 298 #endif
 299   else
 300     return errno;
 301
 302   __set_errno (res);
 303   return res;
 304 }
 305
 306
 307 #ifdef NO_COMPAT_NEEDED
 308 strong_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME);
 309 #elif !defined FUNCTION2_NAME
 310 # include <shlib-compat.h>
 311 # if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
 312 #  define OLD(name) OLD1 (name)
 313 #  define OLD1(name) __old_##name
 314
 315 int
 316 attribute_compat_text_section
 317 OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
 318                       size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
 319 {
 320   int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
 321                                        buflen, result H_ERRNO_VAR);
 322
 323   if (ret != 0 || result == NULL)
 324     ret = -1;
 325
 326   return ret;
 327 }
 328
 329 #  define do_symbol_version(real, name, version) \
 330   compat_symbol (libc, real, name, version)
 331 do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
 332 # endif
 333
 334 /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
 335    in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
 336    hidden too.  */
 337 strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
 338
 339 # define do_default_symbol_version(real, name, version) \
 340   versioned_symbol (libc, real, name, version)
 341 do_default_symbol_version (NEW (REENTRANT_NAME),
 342                            REENTRANT_NAME, GLIBC_2_1_2);
 343 #endif
 344
 345 static_link_warning (REENTRANT_NAME)