nss/getXXent_r.c

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