libio/tst-mmap-setvbuf.c

   1 /* Test setvbuf on readonly fopen (using mmap stdio).
   2    Copyright (C) 2002-2024 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 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 int main (void)
  25 {
  26   char name[] = "/tmp/tst-mmap-setvbuf.XXXXXX";
  27   char buf[4096];
  28   const char * const test = "Let's see if mmap stdio works with setvbuf.\n";
  29   char temp[strlen (test) + 1];
  30   int fd = mkstemp (name);
  31   FILE *f;
  32
  33   if (fd == -1)
  34     {
  35       printf ("%u: cannot open temporary file: %m\n", __LINE__);
  36       exit (1);
  37     }
  38
  39   f = fdopen (fd, "w");
  40   if (f == NULL)
  41     {
  42       printf ("%u: cannot fdopen temporary file: %m\n", __LINE__);
  43       exit (1);
  44     }
  45
  46   fputs (test, f);
  47   fclose (f);
  48
  49   f = fopen (name, "rm");
  50   if (f == NULL)
  51     {
  52       printf ("%u: cannot fopen temporary file: %m\n", __LINE__);
  53       exit (1);
  54     }
  55
  56   if (setvbuf (f, buf, _IOFBF, sizeof buf))
  57     {
  58       printf ("%u: setvbuf failed: %m\n", __LINE__);
  59       exit (1);
  60     }
  61
  62   if (fread (temp, 1, strlen (test), f) != strlen (test))
  63     {
  64       printf ("%u: couldn't read the file back: %m\n", __LINE__);
  65       exit (1);
  66     }
  67   temp [strlen (test)] = '\0';
  68
  69   if (strcmp (test, temp))
  70     {
  71       printf ("%u: read different string than was written:\n%s%s",
  72               __LINE__, test, temp);
  73       exit (1);
  74     }
  75
  76   fclose (f);
  77
  78   unlink (name);
  79   exit (0);
  80 }