nss/getXXent.c

   1 /* Copyright (C) 1996, 1997, 1999, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <bits/libc-lock.h>
  21 #include <stdlib.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 |* GETFUNC_NAME  - name of the non-reentrant getXXXent function    *|
  31 |*                                                                 *|
  32 |* BUFLEN        - size of static buffer                           *|
  33 |*                                                                 *|
  34 |* Optionally the following vars can be defined:                   *|
  35 |*                                                                 *|
  36 |* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
  37 |*                 the global `h_errno' variable.                  *|
  38 |*                                                                 *|
  39 \*******************************************************************/
  40
  41 /* To make the real sources a bit prettier.  */
  42 #define REENTRANT_GETNAME APPEND_R (GETFUNC_NAME)
  43 #define APPEND_R(name) APPEND_R1 (name)
  44 #define APPEND_R1(name) name##_r
  45 #define INTERNAL(name) INTERNAL1 (name)
  46 #define INTERNAL1(name) __##name
  47
  48 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  49 #ifdef NEED_H_ERRNO
  50 # define H_ERRNO_PARM , int *h_errnop
  51 # define H_ERRNO_VAR &h_errno
  52 #else
  53 # define H_ERRNO_PARM
  54 # define H_ERRNO_VAR NULL
  55 #endif
  56
  57 /* Prototype of the reentrant version.  */
  58 extern int INTERNAL (REENTRANT_GETNAME) (LOOKUP_TYPE *resbuf, char *buffer,
  59                                          size_t buflen, LOOKUP_TYPE **result
  60                                          H_ERRNO_PARM);
  61
  62 /* We need to protect the dynamic buffer handling.  */
  63 __libc_lock_define_initialized (static, lock);
  64
  65 /* This points to the static buffer used.  */
  66 static char *buffer;
  67
  68
  69 LOOKUP_TYPE *
  70 GETFUNC_NAME (void)
  71 {
  72   static size_t buffer_size;
  73   static LOOKUP_TYPE resbuf;
  74   LOOKUP_TYPE *result;
  75   int save;
  76
  77   /* Get lock.  */
  78   __libc_lock_lock (lock);
  79
  80   result = (LOOKUP_TYPE *)
  81     __nss_getent ((getent_r_function) INTERNAL (REENTRANT_GETNAME),
  82                   (void **) &resbuf, &buffer, BUFLEN, &buffer_size,
  83                   H_ERRNO_VAR);
  84
  85   save = errno;
  86   __libc_lock_unlock (lock);
  87   __set_errno (save);
  88   return result;
  89 }
  90
  91
  92 /* Free all resources if necessary.  */
  93 static void __attribute__ ((unused))
  94 free_mem (void)
  95 {
  96   free (buffer);
  97 }
  98
  99 text_set_element (__libc_subfreeres, free_mem);