nss/getXXent_r.c

   1 /* Copyright (C) 1996 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
  17 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.  */
  19
  20 #include <libc-lock.h>
  21
  22 #include "nsswitch.h"
  23
  24 /*******************************************************************\
  25 |* Here we assume several symbols to be defined:                   *|
  26 |*                                                                 *|
  27 |* LOOKUP_TYPE   - the return type of the function                 *|
  28 |*                                                                 *|
  29 |* SETFUNC_NAME  - name of the non-reentrant setXXXent function    *|
  30 |*                                                                 *|
  31 |* GETFUNC_NAME  - name of the non-reentrant getXXXent function    *|
  32 |*                                                                 *|
  33 |* ENDFUNC_NAME  - name of the non-reentrant endXXXent function    *|
  34 |*                                                                 *|
  35 |* DATABASE_NAME - name of the database the function accesses      *|
  36 |*                 (e.g., host, services, ...)                     *|
  37 |*                                                                 *|
  38 |* Optionally the following vars can be defined:                   *|
  39 |*                                                                 *|
  40 |* STAYOPEN      - variable declaration for setXXXent function     *|
  41 |*                                                                 *|
  42 |* STAYOPEN_VAR  - variable name for setXXXent function            *|
  43 |*                                                                 *|
  44 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  45 |*                 the global `h_errno' variable.                  *|
  46 |*                                                                 *|
  47 \*******************************************************************/
  48
  49 /* To make the real sources a bit prettier.  */
  50 #define REENTRANT_GETNAME APPEND_R (GETFUNC_NAME)
  51 #define APPEND_R(name) APPEND_R1 (name)
  52 #define APPEND_R1(name) name##_r
  53
  54 #define SETFUNC_NAME_STRING STRINGIZE (SETFUNC_NAME)
  55 #define GETFUNC_NAME_STRING STRINGIZE (GETFUNC_NAME)
  56 #define ENDFUNC_NAME_STRING STRINGIZE (ENDFUNC_NAME)
  57 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
  58 #define STRINGIZE(name) STRINGIZE1 (name)
  59 #define STRINGIZE1(name) #name
  60
  61 #define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
  62 #define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
  63 #define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
  64
  65 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  66 #ifdef NEED_H_ERRNO
  67 # define H_ERRNO_PARM , int *h_errnop
  68 # define H_ERRNO_VAR , &h_errno
  69 #else
  70 # define H_ERRNO_PARM
  71 # define H_ERRNO_VAR
  72 #endif
  73
  74 /* Some databases take the `stayopen' flag.  */
  75 #ifndef STAYOPEN
  76 #define STAYOPEN void
  77 #define STAYOPEN_VAR
  78 #endif
  79
  80 /* Prototype for the setXXXent functions we use here.  */
  81 typedef int (*set_function) (STAYOPEN);
  82
  83 /* Prototype for the endXXXent functions we use here.  */
  84 typedef int (*end_function) (void);
  85
  86 /* Prototype for the setXXXent functions we use here.  */
  87 typedef int (*get_function) (LOOKUP_TYPE *, char *, int H_ERRNO_PARM);
  88
  89
  90 /* This handle for the NSS data base is shared between all
  91    set/get/endXXXent functions.  */
  92 static service_user *nip;
  93 /* Remember the first service_entry, it's always the same.  */
  94 static service_user *startp;
  95
  96 /* Protect above variable against multiple uses at the same time.  */
  97 __libc_lock_define_initialized (static, lock);
  98
  99 /* The lookup function for the first entry of this service.  */
 100 extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp);
 101
 102
 103 void
 104 SETFUNC_NAME (STAYOPEN)
 105 {
 106   set_function fct;
 107   int no_more;
 108
 109 #ifdef NEED__RES
 110   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 111     {
 112       h_errno = NETDB_INTERNAL;
 113       return NULL;
 114     }
 115 #endif /* need _res */
 116
 117   __libc_lock_lock (lock);
 118
 119   if (startp == NULL)
 120     {
 121       no_more = DB_LOOKUP_FCT (&nip, SETFUNC_NAME_STRING, (void **) &fct);
 122       startp = no_more == 0 ? (service_user *) -1 : nip;
 123     }
 124   else
 125     no_more = (nip = startp) != (service_user *) -1;
 126
 127   /* Cycle through all the services and run their setXXent functions.  */
 128   while (! no_more)
 129     {
 130       /* Ignore status, we force check in __NSS_NEXT.  */
 131       (void) (*fct) (STAYOPEN_VAR);
 132
 133       no_more = __nss_next (&nip, SETFUNC_NAME_STRING, (void **) &fct, 0, 1);
 134     }
 135
 136   __libc_lock_unlock (lock);
 137 }
 138
 139
 140 void
 141 ENDFUNC_NAME (void)
 142 {
 143   end_function fct;
 144   int no_more;
 145
 146 #ifdef NEED__RES
 147   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 148     {
 149       h_errno = NETDB_INTERNAL;
 150       return NULL;
 151     }
 152 #endif /* need _res */
 153
 154   __libc_lock_lock (lock);
 155
 156   if (startp == NULL)
 157     {
 158       no_more = DB_LOOKUP_FCT (&nip, SETFUNC_NAME_STRING, (void **) &fct);
 159       startp = no_more == 0 ? (service_user *) -1 : nip;
 160     }
 161   else
 162     no_more = (nip = startp) != (service_user *) -1;
 163
 164   /* Cycle through all the services and run their endXXent functions.  */
 165   while (no_more == 0)
 166     {
 167       /* Ignore status, we force check in __NSS_NEXT.  */
 168       (void) (*fct) ();
 169
 170       no_more = __nss_next (&nip, ENDFUNC_NAME_STRING, (void **) &fct, 0, 1);
 171     }
 172
 173   __libc_lock_unlock (lock);
 174 }
 175
 176
 177 LOOKUP_TYPE *
 178 REENTRANT_GETNAME (LOOKUP_TYPE *result, char *buffer, int buflen H_ERRNO_PARM)
 179 {
 180   get_function fct;
 181   int no_more;
 182   enum nss_status status = NSS_STATUS_NOTFOUND;
 183
 184 #ifdef NEED__RES
 185   if ((_res.options & RES_INIT) == 0 && res_init () == -1)
 186     {
 187       h_errno = NETDB_INTERNAL;
 188       return NULL;
 189     }
 190 #endif /* need _res */
 191
 192   __libc_lock_lock (lock);
 193
 194   if (nip)
 195     /* Continuing a walk-through started before.  */
 196     no_more = 0;
 197   else
 198     {
 199       if (startp == NULL)
 200         {
 201           no_more = DB_LOOKUP_FCT (&nip, SETFUNC_NAME_STRING, (void **) &fct);
 202           startp = no_more == 0 ? (service_user *) -1 : nip;
 203         }
 204       else
 205         no_more = (nip = startp) != (service_user *) -1;
 206
 207       if (no_more != 0)
 208         status = NSS_STATUS_UNAVAIL;
 209     }
 210
 211   while (no_more == 0)
 212     {
 213       status = (*fct) (result, buffer, buflen H_ERRNO_VAR);
 214
 215       no_more = __nss_next (&nip, GETFUNC_NAME_STRING, (void **) &fct,
 216                             status, 0);
 217     }
 218
 219   __libc_lock_unlock (lock);
 220
 221   return status == NSS_STATUS_SUCCESS ? result : NULL;
 222 }