postconf.ml

#load "unix.cma";;
#load "str.cma";;

let re_xen_flags = Str.regexp "^XEN_CFLAGS="

let check_output cmd =
  let from_cmd = Unix.open_process_in cmd in
  let output = input_line from_cmd in
  let status = Unix.close_process_in from_cmd in
  assert (status = Unix.WEXITED 0);
  output

let () =
  let ch = open_in "setup.data" in
  let b = Buffer.create 4000 in
  let xen = ref false in
  try
    while true do
      let line = input_line ch in
      if line = "xen=\"true\"" then xen := true;
      if not (Str.string_match re_xen_flags line 0) then (
        Buffer.add_string b line;
        Buffer.add_char b '\n'
      )
    done
  with End_of_file ->
    close_in ch;

    let xen_cflags =
      if !xen then
        try check_output "pkg-config --static mirage-xen --cflags"
        with Assert_failure _ | End_of_file ->
          check_output
            "env PKG_CONFIG_PATH=`opam config var prefix`/lib/pkgconfig \
             pkg-config --static mirage-xen --cflags"
      else "xen_not_enabled"
    in

    Buffer.add_string b (Printf.sprintf "XEN_CFLAGS=%S\n" xen_cflags);
    let ch = open_out "setup.data" in
    Buffer.output_buffer ch b;
    close_out ch