libio/bug-fseek.c

   1 #include <errno.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5
   6 #include <support/xstdio.h>
   7
   8 static char *fname;
   9
  10
  11 static void do_prepare (void);
  12 #define PREPARE(argc, argv) do_prepare ()
  13 static int do_test (void);
  14 #define TEST_FUNCTION do_test ()
  15 #include <test-skeleton.c>
  16
  17
  18 static void
  19 do_prepare (void)
  20 {
  21   static const char pattern[] = "12345678901234567890";
  22   int fd = create_temp_file ("bug-fseek.", &fname);
  23   if (fd == -1)
  24     {
  25       printf ("cannot create temporary file: %m\n");
  26       exit (1);
  27     }
  28
  29   if (write (fd, pattern, sizeof (pattern)) != sizeof (pattern))
  30     {
  31       perror ("short write");
  32       abort ();
  33     }
  34   close (fd);
  35 }
  36
  37
  38
  39 static int
  40 do_test (void)
  41 {
  42   FILE *f;
  43   int result = 0;
  44   char buf[10];
  45
  46
  47   if ((f = fopen (fname, "r")) == (FILE *) NULL)
  48     {
  49       perror ("fopen(\"r\")");
  50     }
  51
  52   xfread (buf, 3, 1, f);
  53   errno = 0;
  54   if (fseek (f, -10, SEEK_CUR) == 0)
  55     {
  56       printf ("fseek() for r to before start of file worked!\n");
  57       result = 1;
  58     }
  59   else if (errno != EINVAL)
  60     {
  61       printf ("\
  62 fseek() for r to before start of file did not set errno to EINVAL.  \
  63 Got %d instead\n",
  64          errno);
  65       result = 1;
  66     }
  67
  68   fclose (f);
  69
  70
  71   if ((f = fopen (fname, "r+")) == (FILE *) NULL)
  72     {
  73       perror ("fopen(\"r+\")");
  74     }
  75
  76   xfread (buf, 3, 1, f);
  77   errno = 0;
  78   if (fseek (f, -10, SEEK_CUR) == 0)
  79     {
  80       printf ("fseek() for r+ to before start of file worked!\n");
  81       result = 1;
  82     }
  83   else if (errno != EINVAL)
  84     {
  85       printf ("\
  86 fseek() for r+ to before start of file did not set errno to EINVAL.  \
  87 Got %d instead\n",
  88          errno);
  89       result = 1;
  90     }
  91
  92   fclose (f);
  93
  94
  95   if ((f = fopen (fname, "r+")) == (FILE *) NULL)
  96     {
  97       perror ("fopen(\"r+\")");
  98     }
  99
 100   xfread (buf, 3, 1, f);
 101   if (ftell (f) != 3)
 102     {
 103       puts ("ftell failed");
 104       return 1;
 105     }
 106   errno = 0;
 107   if (fseek (f, -10, SEEK_CUR) == 0)
 108     {
 109       printf ("fseek() for r+ to before start of file worked!\n");
 110       result = 1;
 111     }
 112   else if (errno != EINVAL)
 113     {
 114       printf ("\
 115 fseek() for r+ to before start of file did not set errno to EINVAL.  \
 116 Got %d instead\n",
 117          errno);
 118       result = 1;
 119     }
 120
 121   fclose (f);
 122
 123   return result;
 124 }