1  /* Check static buffer handling with setvbuf (BZ #22415)
       2  
       3     Copyright (C) 2017-2023 Free Software Foundation, Inc.
       4     This file is part of the GNU C Library.
       5  
       6     The GNU C Library is free software; you can redistribute it and/or
       7     modify it under the terms of the GNU Lesser General Public
       8     License as published by the Free Software Foundation; either
       9     version 2.1 of the License, or (at your option) any later version.
      10  
      11     The GNU C Library is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14     Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public
      17     License along with the GNU C Library; if not, see
      18     <https://www.gnu.org/licenses/>.  */
      19  
      20  #include <stdio.h>
      21  #include <stdlib.h>
      22  #include <wchar.h>
      23  #include <mcheck.h>
      24  
      25  #include <support/check.h>
      26  #include <support/temp_file.h>
      27  
      28  static int
      29  do_test (void)
      30  {
      31    mtrace ();
      32  
      33    char *temp_file;
      34    TEST_VERIFY_EXIT (create_temp_file ("tst-bz22145.", &temp_file));
      35  
      36    char buf[BUFSIZ];
      37  
      38    {
      39      /* Check if backup buffer is correctly freed and changing back
      40         to normal buffer does not trigger an invalid free in case of
      41         static buffer set by setvbuf.  */
      42  
      43      FILE *f = fopen (temp_file, "w+b");
      44      TEST_VERIFY_EXIT (f != NULL);
      45  
      46      TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0);
      47      TEST_VERIFY_EXIT (ungetc ('x', f) == 'x');
      48      TEST_VERIFY_EXIT (fseek (f, 0L, SEEK_SET) == 0);
      49      TEST_VERIFY_EXIT (fputc ('y', f) ==  'y');
      50  
      51      TEST_VERIFY_EXIT (fclose (f) == 0);
      52    }
      53  
      54    {
      55      /* Check if backup buffer is correctly freed and changing back
      56         to normal buffer does not trigger an invalid free in case of
      57         static buffer set by setvbuf.  */
      58  
      59      FILE *f = fopen (temp_file, "w+b");
      60      TEST_VERIFY_EXIT (f != NULL);
      61  
      62      TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0);
      63      TEST_VERIFY_EXIT (ungetc ('x', f) == 'x');
      64      TEST_VERIFY_EXIT (fputc ('y', f) ==  'y');
      65  
      66      TEST_VERIFY_EXIT (fclose (f) == 0);
      67    }
      68  
      69    {
      70      FILE *f = fopen (temp_file, "w+b");
      71      TEST_VERIFY_EXIT (f != NULL);
      72  
      73      TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0);
      74      TEST_VERIFY_EXIT (ungetwc (L'x', f) == L'x');
      75      TEST_VERIFY_EXIT (fseek (f, 0L, SEEK_SET) == 0);
      76      TEST_VERIFY_EXIT (fputwc (L'y', f) ==  L'y');
      77  
      78      TEST_VERIFY_EXIT (fclose (f) == 0);
      79    }
      80  
      81    {
      82      FILE *f = fopen (temp_file, "w+b");
      83      TEST_VERIFY_EXIT (f != NULL);
      84  
      85      TEST_VERIFY_EXIT (setvbuf (f, buf, _IOFBF, BUFSIZ) == 0);
      86      TEST_VERIFY_EXIT (ungetwc (L'x', f) == L'x');
      87      TEST_VERIFY_EXIT (fputwc (L'y', f) ==  L'y');
      88  
      89      TEST_VERIFY_EXIT (fclose (f) == 0);
      90    }
      91  
      92    free (temp_file);
      93  
      94    return 0;
      95  }
      96  
      97  #include <support/test-driver.c>