libio/bug-fseek.c

   1 #include <errno.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5
   6
   7 static char *fname;
   8
   9
  10 static void do_prepare (void);
  11 #define PREPARE(argc, argv) do_prepare ()
  12 static int do_test (void);
  13 #define TEST_FUNCTION do_test ()
  14 #include <test-skeleton.c>
  15
  16
  17 static void
  18 do_prepare (void)
  19 {
  20   static const char pattern[] = "12345678901234567890";
  21   int fd = create_temp_file ("bug-fseek.", &fname);
  22   if (fd == -1)
  23     {
  24       printf ("cannot create temporary file: %m\n");
  25       exit (1);
  26     }
  27
  28   if (write (fd, pattern, sizeof (pattern)) != sizeof (pattern))
  29     {
  30       perror ("short write");
  31       abort ();
  32     }
  33   close (fd);
  34 }
  35
  36
  37
  38 static int
  39 do_test (void)
  40 {
  41   FILE *f;
  42   int result = 0;
  43   char buf[10];
  44
  45
  46   if ((f = fopen (fname, "r")) == (FILE *) NULL)
  47     {
  48       perror ("fopen(\"r\")");
  49     }
  50
  51   fread (buf, 3, 1, f);
  52   errno = 0;
  53   if (fseek (f, -10, SEEK_CUR) == 0)
  54     {
  55       printf ("fseek() for r to before start of file worked!\n");
  56       result = 1;
  57     }
  58   else if (errno != EINVAL)
  59     {
  60       printf ("\
  61 fseek() for r to before start of file did not set errno to EINVAL.  \
  62 Got %d instead\n",
  63          errno);
  64       result = 1;
  65     }
  66
  67   fclose (f);
  68
  69
  70   if ((f = fopen (fname, "r+")) == (FILE *) NULL)
  71     {
  72       perror ("fopen(\"r+\")");
  73     }
  74
  75   fread (buf, 3, 1, f);
  76   errno = 0;
  77   if (fseek (f, -10, SEEK_CUR) == 0)
  78     {
  79       printf ("fseek() for r+ to before start of file worked!\n");
  80       result = 1;
  81     }
  82   else if (errno != EINVAL)
  83     {
  84       printf ("\
  85 fseek() for r+ to before start of file did not set errno to EINVAL.  \
  86 Got %d instead\n",
  87          errno);
  88       result = 1;
  89     }
  90
  91   fclose (f);
  92
  93
  94   if ((f = fopen (fname, "r+")) == (FILE *) NULL)
  95     {
  96       perror ("fopen(\"r+\")");
  97     }
  98
  99   fread (buf, 3, 1, f);
 100   if (ftell (f) != 3)
 101     {
 102       puts ("ftell failed");
 103       return 1;
 104     }
 105   errno = 0;
 106   if (fseek (f, -10, SEEK_CUR) == 0)
 107     {
 108       printf ("fseek() for r+ to before start of file worked!\n");
 109       result = 1;
 110     }
 111   else if (errno != EINVAL)
 112     {
 113       printf ("\
 114 fseek() for r+ to before start of file did not set errno to EINVAL.  \
 115 Got %d instead\n",
 116          errno);
 117       result = 1;
 118     }
 119
 120   fclose (f);
 121
 122   return result;
 123 }