libio/tst-mmap-setvbuf.c

   1 /* Test setvbuf on readonly fopen (using mmap stdio).
   2    Copyright (C) 2002-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Jakub Jelinek <jakub@redhat.com>, 2002.
   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 <string.h>
  23 #include <unistd.h>
  24
  25 int main (void)
  26 {
  27   char name[] = "/tmp/tst-mmap-setvbuf.XXXXXX";
  28   char buf[4096];
  29   const char * const test = "Let's see if mmap stdio works with setvbuf.\n";
  30   char temp[strlen (test) + 1];
  31   int fd = mkstemp (name);
  32   FILE *f;
  33
  34   if (fd == -1)
  35     {
  36       printf ("%u: cannot open temporary file: %m\n", __LINE__);
  37       exit (1);
  38     }
  39
  40   f = fdopen (fd, "w");
  41   if (f == NULL)
  42     {
  43       printf ("%u: cannot fdopen temporary file: %m\n", __LINE__);
  44       exit (1);
  45     }
  46
  47   fputs (test, f);
  48   fclose (f);
  49
  50   f = fopen (name, "rm");
  51   if (f == NULL)
  52     {
  53       printf ("%u: cannot fopen temporary file: %m\n", __LINE__);
  54       exit (1);
  55     }
  56
  57   if (setvbuf (f, buf, _IOFBF, sizeof buf))
  58     {
  59       printf ("%u: setvbuf failed: %m\n", __LINE__);
  60       exit (1);
  61     }
  62
  63   if (fread (temp, 1, strlen (test), f) != strlen (test))
  64     {
  65       printf ("%u: couldn't read the file back: %m\n", __LINE__);
  66       exit (1);
  67     }
  68   temp [strlen (test)] = '\0';
  69
  70   if (strcmp (test, temp))
  71     {
  72       printf ("%u: read different string than was written:\n%s%s",
  73               __LINE__, test, temp);
  74       exit (1);
  75     }
  76
  77   fclose (f);
  78
  79   unlink (name);
  80   exit (0);
  81 }