libio/bug-mmap-fflush.c

   1 /* Test for bug in fflush synchronization behavior.  */
   2
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6
   7 #include <support/xstdlib.h>
   8
   9 static char *fname;
  10
  11 static void prepare (void);
  12 #define PREPARE(argc, argv) prepare ()
  13
  14
  15 #define TEST_FUNCTION do_test ()
  16 static int do_test (void);
  17 #include "../test-skeleton.c"
  18
  19
  20 static void
  21 prepare (void)
  22 {
  23   int fd = create_temp_file ("bug-mmap-fflush.", &fname);
  24   if (fd == -1)
  25     exit (3);
  26   /* We don't need the descriptor.  */
  27   close (fd);
  28 }
  29
  30
  31 static int
  32 do_test (void)
  33 {
  34   FILE *f;
  35   off_t o;
  36   char buffer[1024];
  37
  38   snprintf (buffer, sizeof (buffer), "echo 'From foo@bar.com' > %s", fname);
  39   xsystem (buffer);
  40
  41   f = fopen (fname, "r");
  42   fseek (f, 0, SEEK_END);
  43   o = ftello (f);
  44   fseek (f, 0, SEEK_SET);
  45   fflush (f);
  46   snprintf (buffer, sizeof (buffer), "echo 'From bar@baz.edu' >> %s", fname);
  47   xsystem (buffer);
  48
  49   fseek (f, o, SEEK_SET);
  50   if (fgets (buffer, 1024, f) == NULL)
  51     exit (1);
  52   if (strncmp (buffer, "From ", 5) != 0)
  53     exit (1);
  54   fclose (f);
  55   exit (0);
  56 }