nss/getXXent.c

   1 /* Copyright (C) 1996-2023 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, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <libc-lock.h>
  20 #include <stdlib.h>
  21 #include <set-freeres.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 #define APPEND_FREEMEM_NAME1(name) __libc_##name##_freemem_ptr
  48 #define APPEND_FREEMEM_NAME(name) APPEND_FREEMEM_NAME1(name)
  49 #define FREEMEM_NAME APPEND_FREEMEM_NAME (GETFUNC_NAME)
  50
  51 /* Sometimes we need to store error codes in the `h_errno' variable.  */
  52 #ifdef NEED_H_ERRNO
  53 # define H_ERRNO_PARM , int *h_errnop
  54 # define H_ERRNO_VAR &h_errno
  55 #else
  56 # define H_ERRNO_PARM
  57 # define H_ERRNO_VAR NULL
  58 #endif
  59
  60 /* Prototype of the reentrant version.  */
  61 extern int INTERNAL (REENTRANT_GETNAME) (LOOKUP_TYPE *resbuf, char *buffer,
  62                                          size_t buflen, LOOKUP_TYPE **result
  63                                          H_ERRNO_PARM) attribute_hidden;
  64
  65 /* We need to protect the dynamic buffer handling.  */
  66 __libc_lock_define_initialized (static, lock);
  67
  68 /* This points to the static buffer used.  */
  69 static char *buffer;
  70
  71 weak_alias (buffer, FREEMEM_NAME)
  72
  73 LOOKUP_TYPE *
  74 GETFUNC_NAME (void)
  75 {
  76   static size_t buffer_size;
  77   static union
  78   {
  79     LOOKUP_TYPE l;
  80     void *ptr;
  81   } resbuf;
  82   LOOKUP_TYPE *result;
  83   int save;
  84
  85   /* Get lock.  */
  86   __libc_lock_lock (lock);
  87
  88   result = (LOOKUP_TYPE *)
  89     __nss_getent ((getent_r_function) INTERNAL (REENTRANT_GETNAME),
  90                   &resbuf.ptr, &buffer, BUFLEN, &buffer_size,
  91                   H_ERRNO_VAR);
  92
  93   save = errno;
  94   __libc_lock_unlock (lock);
  95   __set_errno (save);
  96   return result;
  97 }
  98
  99 nss_interface_function (GETFUNC_NAME)