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: }