[syslinux] tftpd-hpa suggestions

[Baurjan Ismagulov]

Hello, Peter and others!

there are some issues regarding the tftp-hpa server:

1. Running as Windows service seems to require that the application does
   not detach (otherwise "net start" says smth. like "could not start,
   the service didn't report any errors").

   The attached patch adds the option "-n", which can be used to have
   tftpd run in foreground.

2. By default, tftpd tries to drop privileges. Under Windows, this
   requires:

   * creation of user "nobody", not present by default;

   * granting special privileges to the user running the daemon (the
     default choice is "SYSTEM" if run as a service) -- namely, running
     processes as another user without giving the password (smth.
     similar to SUID).

   This leads to the following problems:

   * I don't see much sense in granting powerful privileges in order to
     immediately drop them.

   * According to one of the leading cygwin developers, this would not
     work under Windows 2003 since the system drops these privileges
     automatically before starting the service
     (http://marc.theaimsgroup.com/?l=cygwin&m=107003209905031&w=2).

   That is why it was recommended to me to use the daemon without
   switching to nobody. In order to further minimize the risk, one can
   run the service as some special user, created specifically for that
   purpose.

   The attached patch #ifdefs the relevant code -- I didn't implement it
   as an option since I couldn't imagine a scenario where one could need
   it as an option.

3. The server seems to have at least one command line syntax example
   where the directory name is not required. I have changed the man page
   accordingly.

I suggest to include these changes in the distribution. What do you
think?

With kind regards,
Baurjan.