libio/bug-ungetc4.c

   1 /* Test program for ungetc/fseekpos interaction.
   2    Copyright (C) 2004-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20
  21 static void do_prepare (void);
  22 #define PREPARE(argc, argv) do_prepare ()
  23 static int do_test (void);
  24 #define TEST_FUNCTION do_test ()
  25 #include "../test-skeleton.c"
  26
  27 static const char pattern[] = "abcdefghijklmnopqrstuvwxyz";
  28 static char *temp_file;
  29
  30 static void
  31 do_prepare (void)
  32 {
  33   int fd = create_temp_file ("bug-ungetc.", &temp_file);
  34   if (fd == -1)
  35     {
  36       printf ("cannot create temporary file: %m\n");
  37       exit (1);
  38     }
  39   write (fd, pattern, sizeof (pattern) - 1);
  40   close (fd);
  41 }
  42
  43 #define TEST_POS 5
  44
  45 static int
  46 do_one_test (int mode)
  47 {
  48   FILE *f = fopen (temp_file, "r");
  49   if (f == NULL)
  50     {
  51       printf ("%d: could not open temporary file: %m\n", mode);
  52       return 1;
  53     }
  54
  55   int i;
  56   for (i = 0; i < TEST_POS; ++i)
  57     getc (f);
  58
  59   fpos_t p;
  60   if (fgetpos (f, &p) != 0)
  61     {
  62       printf ("%d: fgetpos failed: %m\n", mode);
  63       return 1;
  64     }
  65
  66   if (mode)
  67     {
  68       if (fseek (f, 0, SEEK_SET) != 0)
  69         {
  70           printf ("%d: fseek failed: %m\n", mode);
  71           return 1;
  72         }
  73
  74       for (i = 0; i < TEST_POS - (mode >= 2); ++i)
  75         getc (f);
  76     }
  77
  78   if (mode != 2 && ungetc ('X', f) != 'X')
  79     {
  80       printf ("%d: ungetc failed\n", mode);
  81       return 1;
  82     }
  83
  84   if (mode == 3 && getc (f) != 'X')
  85     {
  86       printf ("%d: getc after ungetc did not return X\n", mode);
  87       return 1;
  88     }
  89
  90   if (fsetpos (f, &p) != 0)
  91     {
  92       printf ("%d: fsetpos failed: %m\n", mode);
  93       return 1;
  94     }
  95
  96   if (getc (f) != pattern[TEST_POS])
  97     {
  98       printf ("%d: getc did not return %c\n", mode, pattern[TEST_POS]);
  99       return 1;
 100     }
 101
 102   fclose (f);
 103
 104   return 0;
 105 }
 106
 107 static int
 108 do_test (void)
 109 {
 110   int mode, ret = 0;
 111   for (mode = 0; mode <= 4; mode++)
 112     ret |= do_one_test (mode);
 113   return ret;
 114 }