nss/rewrite_field.c

   1 /* Copyright (C) 2015-2022 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 <nss.h>
  19 #include <string.h>
  20
  21 /* Rewrite VALUE to a valid field value in the NSS database.  Invalid
  22    characters are replaced with a single space character ' '.  If
  23    VALUE is NULL, the empty string is returned.  *TO_BE_FREED is
  24    overwritten with a pointer the caller has to free if the function
  25    returns successfully.  On failure, return NULL.  */
  26 const char *
  27 __nss_rewrite_field (const char *value, char **to_be_freed)
  28 {
  29   *to_be_freed = NULL;
  30   if (value == NULL)
  31     return "";
  32
  33   /* Search for non-allowed characters.  */
  34   const char *p = strpbrk (value, __nss_invalid_field_characters);
  35   if (p == NULL)
  36     return value;
  37   *to_be_freed = __strdup (value);
  38   if (*to_be_freed == NULL)
  39     return NULL;
  40
  41   /* Switch pointer to freshly-allocated buffer.  */
  42   char *bad = *to_be_freed + (p - value);
  43   do
  44     {
  45       *bad = ' ';
  46       bad = strpbrk (bad + 1, __nss_invalid_field_characters);
  47     }
  48   while (bad != NULL);
  49
  50   return *to_be_freed;
  51 }