##-
# Author: Brian Tiffin
# Dedicated to the public domain
#
# Date: September, 2016
# Modified: 2016-10-03/22:39-0400
##+
#
# chroot.icn, Demonstrate chroot, the filesystem root directory function
#
# Seeing as this program is evaluated during document generation it is
# very likely to fail.  The book is never built using root permissions.
#
procedure main()
    # Change filesystem root to protect outside directories
    #  from unprivileged access.  Requires CAP_SYS_CHROOT capabilities.
    if newroot := chroot("/home/btiffin") then {
        write(image(newroot))
        chdir("/")
        write(chdir())
        d := open(".", "r")
        while write(read(d))
        close(d)
    } else write("no permission to set new root directory")
end