libio/bug-ungetc4.c

   1 /* Test program for ungetc/fseekpos interaction.
   2    Copyright (C) 2004-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Jakub Jelinek <jakub@redhat.com>, 2004.
   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
  22 static void do_prepare (void);
  23 #define PREPARE(argc, argv) do_prepare ()
  24 static int do_test (void);
  25 #define TEST_FUNCTION do_test ()
  26 #include "../test-skeleton.c"
  27
  28 static const char pattern[] = "abcdefghijklmnopqrstuvwxyz";
  29 static char *temp_file;
  30
  31 static void
  32 do_prepare (void)
  33 {
  34   int fd = create_temp_file ("bug-ungetc.", &temp_file);
  35   if (fd == -1)
  36     {
  37       printf ("cannot create temporary file: %m\n");
  38       exit (1);
  39     }
  40   write (fd, pattern, sizeof (pattern) - 1);
  41   close (fd);
  42 }
  43
  44 #define TEST_POS 5
  45
  46 static int
  47 do_one_test (int mode)
  48 {
  49   FILE *f = fopen (temp_file, "r");
  50   if (f == NULL)
  51     {
  52       printf ("%d: could not open temporary file: %m\n", mode);
  53       return 1;
  54     }
  55
  56   int i;
  57   for (i = 0; i < TEST_POS; ++i)
  58     getc (f);
  59
  60   fpos_t p;
  61   if (fgetpos (f, &p) != 0)
  62     {
  63       printf ("%d: fgetpos failed: %m\n", mode);
  64       return 1;
  65     }
  66
  67   if (mode)
  68     {
  69       if (fseek (f, 0, SEEK_SET) != 0)
  70         {
  71           printf ("%d: fseek failed: %m\n", mode);
  72           return 1;
  73         }
  74
  75       for (i = 0; i < TEST_POS - (mode >= 2); ++i)
  76         getc (f);
  77     }
  78
  79   if (mode != 2 && ungetc ('X', f) != 'X')
  80     {
  81       printf ("%d: ungetc failed\n", mode);
  82       return 1;
  83     }
  84
  85   if (mode == 3 && getc (f) != 'X')
  86     {
  87       printf ("%d: getc after ungetc did not return X\n", mode);
  88       return 1;
  89     }
  90
  91   if (fsetpos (f, &p) != 0)
  92     {
  93       printf ("%d: fsetpos failed: %m\n", mode);
  94       return 1;
  95     }
  96
  97   if (getc (f) != pattern[TEST_POS])
  98     {
  99       printf ("%d: getc did not return %c\n", mode, pattern[TEST_POS]);
 100       return 1;
 101     }
 102
 103   fclose (f);
 104
 105   return 0;
 106 }
 107
 108 static int
 109 do_test (void)
 110 {
 111   int mode, ret = 0;
 112   for (mode = 0; mode <= 4; mode++)
 113     ret |= do_one_test (mode);
 114   return ret;
 115 }