id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
4439	Possible infinite loop in boost:: filesystem::copy_file for unix	Roberto Carlos Toledano Gómez <rctg82@…>	Beman Dawes	"In the write cycle:


      do
      {
        if ((sz = ::write(outfile, buf.get() + sz_write,
          sz_read - sz_write))< 0)
        { 
          sz_read = sz; // cause read loop termination
          break;        //  and error to be thrown after closes
        }
        sz_write += sz;
      } while (sz_write < sz_read);
    



Always try to write a number of bytes strictly greater than zero and the api ::write returns according to the official documentation :"" On  success,  the  number of bytes written is returned (Zero Indicates Nothing Was Written).  On error, -1 is returned, and errno is set appropriately"". Now imagine that the ::write api for any error or side effect, always returns zero, then we are in an infinite loop.

To fix it I think the appropriate condition should be:

  if ((sz =:: write (outfile, buf.get () + sz_write,
          sz_read - sz_write)) <= 0)

that is, change the Boolean operation for less than or equal to (<=)

If I'm wrong please let me know what to learn. In my opinion you are the best."	Bugs	closed	Boost 1.44.0	filesystem	Boost Development Trunk	Problem	duplicate	copy, filesystem