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