nss/getnssent.c

   1 /* Copyright (C) 2000-2022 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 <stdlib.h>
  20 #include <netdb.h>
  21 #include "nsswitch.h"
  22
  23 void *
  24 __nss_getent (getent_r_function func, void **resbuf, char **buffer,
  25               size_t buflen, size_t *buffer_size, int *h_errnop)
  26 {
  27   void *result;
  28
  29   if (*buffer == NULL)
  30     {
  31       *buffer_size = buflen;
  32       *buffer = malloc (*buffer_size);
  33     }
  34
  35   while (*buffer != NULL
  36          && func (resbuf, *buffer, *buffer_size, &result, h_errnop) == ERANGE
  37          && (h_errnop == NULL || *h_errnop == NETDB_INTERNAL))
  38     {
  39       char *new_buf;
  40       *buffer_size *= 2;
  41       new_buf = realloc (*buffer, *buffer_size);
  42       if (new_buf == NULL)
  43         {
  44           /* We are out of memory.  Free the current buffer so that the
  45              process gets a chance for a normal termination.  */
  46           int save = errno;
  47           free (*buffer);
  48           __set_errno (save);
  49         }
  50       *buffer = new_buf;
  51     }
  52
  53   if (*buffer == NULL)
  54     result = NULL;
  55
  56   return result;
  57 }