libxl: ocaml: add console reader functions

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Acked-by: David Scott <dave.scott@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/ocaml/libs/xl/xenlight.ml.in

@@ -49,6 +49,13 @@ module Domain = struct
 end
 
 module Host = struct
+	type console_reader
+	exception End_of_file
+
+	external xen_console_read_start : ctx -> int -> console_reader  = "stub_libxl_xen_console_read_start"
+	external xen_console_read_line : ctx -> console_reader -> string = "stub_libxl_xen_console_read_line"
+	external xen_console_read_finish : ctx -> console_reader -> unit = "stub_libxl_xen_console_read_finish"
+
 	external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
 end
 
@@ -82,5 +89,6 @@ module Async = struct
 end
 
 let register_exceptions () =
-	Callback.register_exception "Xenlight.Error" (Error(ERROR_FAIL, ""))
+	Callback.register_exception "Xenlight.Error" (Error(ERROR_FAIL, ""));
+	Callback.register_exception "Xenlight.Host.End_of_file" (Host.End_of_file)
 

tools/ocaml/libs/xl/xenlight.mli.in

@@ -51,6 +51,13 @@ module Domain : sig
 end
 
 module Host : sig
+	type console_reader
+	exception End_of_file
+
+	external xen_console_read_start : ctx -> int -> console_reader  = "stub_libxl_xen_console_read_start"
+	external xen_console_read_line : ctx -> console_reader -> string = "stub_libxl_xen_console_read_line"
+	external xen_console_read_finish : ctx -> console_reader -> unit = "stub_libxl_xen_console_read_finish"
+
 	external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
 end
 

tools/ocaml/libs/xl/xenlight_stubs.c

@@ -939,6 +939,74 @@ value stub_xl_send_debug_keys(value ctx, value keys)
 	CAMLreturn(Val_unit);
 }
 
+static struct custom_operations libxl_console_reader_custom_operations = {
+	"libxl_console_reader_custom_operations",
+	custom_finalize_default,
+	custom_compare_default,
+	custom_hash_default,
+	custom_serialize_default,
+	custom_deserialize_default
+};
+
+#define Console_reader_val(x)(*((libxl_xen_console_reader **) Data_custom_val(x)))
+
+value stub_libxl_xen_console_read_start(value ctx, value clear)
+{
+	CAMLparam2(ctx, clear);
+	CAMLlocal1(handle);
+	libxl_xen_console_reader *cr;
+
+	cr = libxl_xen_console_read_start(CTX, Int_val(clear));
+
+	handle = caml_alloc_custom(&libxl_console_reader_custom_operations, sizeof(cr), 0, 1);
+	Console_reader_val(handle) = cr;
+
+	CAMLreturn(handle);
+}
+
+static void raise_eof(void)
+{
+	static value *exc = NULL;
+
+	/* First time around, lookup by name */
+	if (!exc)
+		exc = caml_named_value("Xenlight.Host.End_of_file");
+
+	if (!exc)
+		caml_invalid_argument("Exception Xenlight.Host.End_of_file not initialized, please link xenlight.cma");
+
+	caml_raise_constant(*exc);
+}
+
+value stub_libxl_xen_console_read_line(value ctx, value reader)
+{
+	CAMLparam2(ctx, reader);
+	CAMLlocal1(line);
+	int ret;
+	char *c_line;
+	libxl_xen_console_reader *cr = (libxl_xen_console_reader *) Console_reader_val(reader);
+
+	ret = libxl_xen_console_read_line(CTX, cr, &c_line);
+
+	if (ret < 0)
+		failwith_xl(ret, "xen_console_read_line");
+	if (ret == 0)
+		raise_eof();
+
+	line = caml_copy_string(c_line);
+
+	CAMLreturn(line);
+}
+
+value stub_libxl_xen_console_read_finish(value ctx, value reader)
+{
+	CAMLparam2(ctx, reader);
+	libxl_xen_console_reader *cr = (libxl_xen_console_reader *) Console_reader_val(reader);
+
+	libxl_xen_console_read_finish(CTX, cr);
+
+	CAMLreturn(Val_unit);
+}
 
 /* Event handling */
 

tools/ocaml/test/Makefile

@@ -9,9 +9,9 @@ OCAMLINCLUDE += \
 	-I $(OCAML_TOPLEVEL)/libs/xentoollog \
 	-I $(OCAML_TOPLEVEL)/libs/xl
 
-OBJS = xtl send_debug_keys list_domains raise_exception
+OBJS = xtl send_debug_keys list_domains raise_exception dmesg
 
-PROGRAMS = xtl send_debug_keys list_domains raise_exception
+PROGRAMS = xtl send_debug_keys list_domains raise_exception dmesg
 
 xtl_LIBS =  \
 	-ccopt -L -ccopt $(OCAML_TOPLEVEL)/libs/xentoollog $(OCAML_TOPLEVEL)/libs/xentoollog/xentoollog.cmxa \
@@ -37,7 +37,13 @@ raise_exception_LIBS =  \
 
 raise_exception_OBJS = raise_exception
 
-OCAML_PROGRAM = xtl send_debug_keys list_domains raise_exception
+dmesg_LIBS =  \
+	-ccopt -L -ccopt $(OCAML_TOPLEVEL)/libs/xentoollog $(OCAML_TOPLEVEL)/libs/xentoollog/xentoollog.cmxa \
+	-ccopt -L -ccopt $(OCAML_TOPLEVEL)/libs/xl $(OCAML_TOPLEVEL)/libs/xl/xenlight.cmxa
+
+dmesg_OBJS = xtl dmesg
+
+OCAML_PROGRAM = xtl send_debug_keys list_domains raise_exception dmesg
 
 all: $(PROGRAMS)
 

tools/ocaml/test/dmesg.ml

@@ -0,0 +1,18 @@
+open Printf
+
+let _ =
+	Xenlight.register_exceptions ();
+	let logger = Xtl.create_stdio_logger ~level:Xentoollog.Debug () in
+	let ctx = Xenlight.ctx_alloc logger in
+
+	let open Xenlight.Host in
+	let reader = xen_console_read_start ctx 0 in
+	(try
+		while true do
+			let line = xen_console_read_line ctx reader in
+			print_string line
+		done
+	with End_of_file -> ());
+	let _ = xen_console_read_finish ctx reader in
+	()
+