nss/getXXent_r.c

   1 /* Copyright (C) 1996, 1997, 1998 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <bits/libc-lock.h>
  22
  23 #include "nsswitch.h"
  24
  25 /*******************************************************************\
  26 |* Here we assume several symbols to be defined:                   *|
  27 |*                                                                 *|
  28 |* LOOKUP_TYPE   - the return type of the function                 *|
  29 |*                                                                 *|
  30 |* SETFUNC_NAME  - name of the non-reentrant setXXXent function    *|
  31 |*                                                                 *|
  32 |* GETFUNC_NAME  - name of the non-reentrant getXXXent function    *|
  33 |*                                                                 *|
  34 |* ENDFUNC_NAME  - name of the non-reentrant endXXXent function    *|
  35 |*                                                                 *|
  36 |* DATABASE_NAME - name of the database the function accesses      *|
  37 |*                 (e.g., host, services, ...)                     *|
  38 |*                                                                 *|
  39 |* Optionally the following vars can be defined:                   *|
  40 |*                                                                 *|
  41 |* STAYOPEN      - variable declaration for setXXXent function     *|
  42 |*                                                                 *|
  43 |* STAYOPEN_VAR  - variable name for setXXXent function            *|
  44 |*                                                                 *|
  45 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  46 |*                 the global `h_errno' variable.                  *|
  47 |*                                                                 *|
  48 \*******************************************************************/
  49
  50 /* To make the real sources a bit prettier.  */
  51 #define REENTRANT_GETNAME APPEND_R (GETFUNC_NAME)
  52 #define APPEND_R(Name) CONCAT2_2 (Name, _r)
  53 #define INTERNAL(Name) CONCAT2_2 (__, Name)
  54 #define CONCAT2_1(Pre, Post) CONCAT2_2 (Pre, Post)
  55 #define CONCAT2_2(Pre, Post) Pre##Post
  56
  57 #define SETFUNC_NAME_STRING STRINGIZE (SETFUNC_NAME)
  58 #define GETFUNC_NAME_STRING STRINGIZE (REENTRANT_GETNAME)
  59 #define ENDFUNC_NAME_STRING STRINGIZE (ENDFUNC_NAME)
  60 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  61 #define STRINGIZE(Name) STRINGIZE1 (Name)
  62 #define STRINGIZE1(Name) #Name
  63
  64 #define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  65 #define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  66 #define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  67
  68 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  69 #ifdef NEED_H_ERRNO
  70 # define H_ERRNO_PARM , int *h_errnop
  71 # define H_ERRNO_VAR , &h_errno
  72 #else
  73 # define H_ERRNO_PARM
  74 # define H_ERRNO_VAR
  75 #endif
  76
  77 /* Some databases take the `stayopen' flag.  */
  78 #ifdef STAYOPEN
  79 # define STAYOPEN_TMP CONCAT2_1 (STAYOPEN, _tmp)
  80 # define STAYOPEN_TMPVAR CONCAT2_1 (STAYOPEN_VAR, _tmp)
  81 #else
  82 # define STAYOPEN void
  83 # define STAYOPEN_VAR
  84 # define STAYOPEN_TMPVAR
  85 #endif
  86
  87 /* Prototype for the setXXXent functions we use here.  */
  88 typedef enum nss_status (*set_function) (STAYOPEN);
  89
  90 /* Prototype for the endXXXent functions we use here.  */
  91 typedef enum nss_status (*end_function) (void);
  92
  93 /* Prototype for the setXXXent functions we use here.  */
  94 typedef enum nss_status (*get_function) (LOOKUP_TYPE *, char *, size_t, int *
  95                                          H_ERRNO_PARM);
  96
  97
  98 /* This handle for the NSS data base is shared between all
  99    set/get/endXXXent functions.  */
 100 static service_user *nip;
 101 /* Remember the last service used since the last call to  `endXXent'.  */
 102 static service_user *last_nip;
 103 /* Remember the first service_entry, it's always the same.  */
 104 static service_user *startp;
 105
 106 #ifdef STAYOPEN_TMP
 107 /* We need to remember the last `stayopen' flag given by the user
 108    since the `setent' function is only called for the first available
 109    service.  */
 110 static STAYOPEN_TMP;
 111 #endif
 112
 113 /* Protect above variable against multiple uses at the same time.  */
 114 __libc_lock_define_initialized (static, lock)
 115
 116 /* The lookup function for the first entry of this service.  */
 117 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp);
 118
 119 /* Set up NIP to run through the services.  If ALL is zero, use NIP's
 120    current location if it's not nil.  Return nonzero if there are no
 121    services (left).  */
 122 static enum nss_status
 123 setup (void **fctp, const char *func_name, int all)
 124 {
 125   int no_more;
 126   if (startp == NULL)
 127     {
 128       no_more = DB_LOOKUP_FCT (&nip, func_name, fctp);
 129       startp = no_more ? (service_user *) -1l : nip;
 130     }
 131   else if (startp == (service_user *) -1l)
 132     /* No services at all.  */
 133     return 1;
 134   else
 135     {
 136       if (all || !nip)
 137         /* Reset to the beginning of the service list.  */
 138         nip = startp;
 139       /* Look up the first function.  */
 140       no_more = __nss_lookup (&nip, func_name, fctp);
 141     }
 142   return no_more;
 143 }
 144 \f
 145 void
 146 SETFUNC_NAME (STAYOPEN)
 147 {
 148   set_function fct;
 149   int no_more;
 150
 151 #ifdef NEED__RES
 152   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 153     {
 154       __set_h_errno (NETDB_INTERNAL);
 155       return;
 156     }
 157 #endif /* need _res */
 158
 159   __libc_lock_lock (lock);
 160
 161   /* Cycle through the services and run their `setXXent' functions until
 162      we find an available service.  */
 163   no_more = setup ((void **) &fct, SETFUNC_NAME_STRING, 1);
 164   while (! no_more)
 165     {
 166       int is_last_nip = nip == last_nip;
 167       enum nss_status status = _CALL_DL_FCT (fct, (STAYOPEN_VAR));
 168
 169       no_more = __nss_next (&nip, SETFUNC_NAME_STRING, (void **) &fct,
 170                             status, 0);
 171       if (is_last_nip)
 172         last_nip = nip;
 173     }
 174
 175 #ifdef STAYOPEN_TMP
 176   STAYOPEN_TMPVAR = STAYOPEN_VAR;
 177 #endif
 178
 179   __libc_lock_unlock (lock);
 180 }
 181
 182
 183 void
 184 ENDFUNC_NAME (void)
 185 {
 186   end_function fct;
 187   int no_more;
 188
 189 #ifdef NEED__RES
 190   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 191     {
 192       __set_h_errno (NETDB_INTERNAL);
 193       return;
 194     }
 195 #endif /* need _res */
 196
 197   __libc_lock_lock (lock);
 198
 199   /* Cycle through all the services and run their endXXent functions.  */
 200   no_more = setup ((void **) &fct, ENDFUNC_NAME_STRING, 1);
 201   while (! no_more)
 202     {
 203       /* Ignore status, we force check in __NSS_NEXT.  */
 204       _CALL_DL_FCT (fct, ());
 205
 206       if (nip == last_nip)
 207         /* We have processed all services which were used.  */
 208         break;
 209
 210       no_more = __nss_next (&nip, ENDFUNC_NAME_STRING, (void **) &fct, 0, 1);
 211     }
 212   last_nip = nip = NULL;
 213
 214   __libc_lock_unlock (lock);
 215 }
 216
 217
 218 int
 219 INTERNAL (REENTRANT_GETNAME) (LOOKUP_TYPE *resbuf, char *buffer, size_t buflen,
 220                               LOOKUP_TYPE **result H_ERRNO_PARM)
 221 {
 222   get_function fct;
 223   int no_more;
 224   enum nss_status status;
 225
 226 #ifdef NEED__RES
 227   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 228     {
 229       __set_h_errno (NETDB_INTERNAL);
 230       *result = NULL;
 231       return -1;
 232     }
 233 #endif /* need _res */
 234
 235   /* Initialize status to return if no more functions are found.  */
 236   status = NSS_STATUS_NOTFOUND;
 237
 238   __libc_lock_lock (lock);
 239
 240   /* Run through available functions, starting with the same function last
 241      run.  We will repeat each function as long as it succeeds, and then go
 242      on to the next service action.  */
 243   no_more = setup ((void **) &fct, GETFUNC_NAME_STRING, 0);
 244   while (! no_more)
 245     {
 246       int is_last_nip = nip == last_nip;
 247
 248       status = _CALL_DL_FCT (fct,
 249                              (resbuf, buffer, buflen, &errno H_ERRNO_VAR));
 250
 251       /* The the status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
 252          provided buffer is too small.  In this case we should give
 253          the user the possibility to enlarge the buffer and we should
 254          not simply go on with the next service (even if the TRYAGAIN
 255          action tells us so).  */
 256       if (status == NSS_STATUS_TRYAGAIN
 257 #ifdef NEED_H_ERRNO
 258           && *h_errnop == NETDB_INTERNAL
 259 #endif
 260           && errno == ERANGE)
 261         break;
 262
 263       do
 264         {
 265           no_more = __nss_next (&nip, GETFUNC_NAME_STRING, (void **) &fct,
 266                                 status, 0);
 267
 268           if (is_last_nip)
 269             last_nip = nip;
 270
 271           if (! no_more)
 272             {
 273               /* Call the `setXXent' function.  This wasn't done before.  */
 274               set_function sfct;
 275
 276               no_more = __nss_lookup (&nip, SETFUNC_NAME_STRING,
 277                                       (void **) &sfct);
 278
 279               if (! no_more)
 280                 status = _CALL_DL_FCT (sfct, (STAYOPEN_TMPVAR));
 281               else
 282                 status = NSS_STATUS_NOTFOUND;
 283             }
 284         }
 285       while (! no_more && status != NSS_STATUS_SUCCESS);
 286     }
 287
 288   __libc_lock_unlock (lock);
 289
 290   *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
 291   return status == NSS_STATUS_SUCCESS ? 0 : -1;
 292 }
 293 #define do_weak_alias(n1, n2) weak_alias (n1, n2)
 294 do_weak_alias (INTERNAL (REENTRANT_GETNAME), REENTRANT_GETNAME)