If the disk is full or directories are nested too deep, and the user
gives first one directory name (which djtar fails to create) and on
the next try gives a directory name that is longer than the first
djtar loops, making the directory name longer and longer and finally
overwrites the stack. 

*** djlib/src/utils/djtar/djtar.org     Thu Jan  1 16:35:50 1998
--- djlib/src/utils/djtar/djtar.c       Fri Mar 13 23:23:06 1998
***************
*** 234,240 ****
--- 234,246 ----
          break;
        r = mkdir (n, 0777);
        if (r)
+       {
+         if(errno == ENOENT)
+         {
+           Fatal("Unable to create directory");
+         }
          r = change(n, "Unable to create directory", 1);
+       }
        } while (r);
        *sl = save;
      }
***************
*** 446,451 ****
--- 452,461 ----
      {
        status = change(dirname, "Duplicate directory name", 2);
        continue;
+     }
+     if (status && (errno==ENOENT))
+     {
+       Fatal("Unable to create directory");
      }
      if (status)
        status = change(dirname, "Unable to create directory", 1);

djtar can still be made to loop endlessly, but without overwriting the 
stack, on the right input in plain DOS.

Say you have a tar file containing the directories "1/aaaaaaaa" 
(eight As) and "1/aaaaaaaaa" (nine As). djtar creates the first 
directory, but fails on the second (as it is the same name in  plain 
DOS). The user is asked for a new name, he answers "aaaaaaaa" (eight 
As), which will fail. Then he answers "aaaaaaaaa" (nine As). 
Ergo loop.