ocaml/debugger/dynlink.ml

252 lines
8.6 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the GNU Library General Public License, with *)
(* the special exception on linking described in file ../../LICENSE. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Dynamic loading of .cmo files *)
(* This is a copy of ../otherlibs/dynlink/dynlink.ml that does not
use Dynlinkaux (the module that packs some of the compiler modules). *)
open Cmo_format
type linking_error =
Undefined_global of string
| Unavailable_primitive of string
| Uninitialized_global of string
type error =
Not_a_bytecode_file of string
| Inconsistent_import of string
| Unavailable_unit of string
| Unsafe_file
| Linking_error of string * linking_error
| Corrupted_interface of string
| File_not_found of string
| Cannot_open_dll of string
exception Error of error
(* Management of interface CRCs *)
let crc_interfaces = ref (Consistbl.create ())
let allow_extension = ref true
(* Check that the object file being loaded has been compiled against
the same interfaces as the program itself. In addition, check that
only authorized compilation units are referenced. *)
let check_consistency file_name cu =
try
List.iter
(fun (name, crc) ->
if name = cu.cu_name then
Consistbl.set !crc_interfaces name crc file_name
else if !allow_extension then
Consistbl.check !crc_interfaces name crc file_name
else
Consistbl.check_noadd !crc_interfaces name crc file_name)
cu.cu_imports
with Consistbl.Inconsistency(name, user, auth) ->
raise(Error(Inconsistent_import name))
| Consistbl.Not_available(name) ->
raise(Error(Unavailable_unit name))
(* Empty the crc_interfaces table *)
let clear_available_units () =
Consistbl.clear !crc_interfaces;
allow_extension := false
(* Allow only access to the units with the given names *)
let allow_only names =
Consistbl.filter (fun name -> List.mem name names) !crc_interfaces;
allow_extension := false
(* Prohibit access to the units with the given names *)
let prohibit names =
Consistbl.filter (fun name -> not (List.mem name names)) !crc_interfaces;
allow_extension := false
(* Initialize the crc_interfaces table with a list of units with fixed CRCs *)
let add_available_units units =
List.iter (fun (unit, crc) -> Consistbl.set !crc_interfaces unit crc "")
units
(* Default interface CRCs: those found in the current executable *)
let default_crcs = ref []
let default_available_units () =
clear_available_units();
add_available_units !default_crcs;
allow_extension := true
(* Initialize the linker tables and everything *)
let init () =
default_crcs := Symtable.init_toplevel();
default_available_units ()
(* Read the CRC of an interface from its .cmi file *)
let digest_interface unit loadpath =
let filename =
let shortname = unit ^ ".cmi" in
try
Misc.find_in_path_uncap loadpath shortname
with Not_found ->
raise (Error(File_not_found shortname)) in
let ic = open_in_bin filename in
try
let buffer = String.create (String.length Config.cmi_magic_number) in
really_input ic buffer 0 (String.length Config.cmi_magic_number);
if buffer <> Config.cmi_magic_number then begin
close_in ic;
raise(Error(Corrupted_interface filename))
end;
ignore (input_value ic);
let crc =
match input_value ic with
(_, crc) :: _ -> crc
| _ -> raise(Error(Corrupted_interface filename))
in
close_in ic;
crc
with End_of_file | Failure _ ->
close_in ic;
raise(Error(Corrupted_interface filename))
(* Initialize the crc_interfaces table with a list of units.
Their CRCs are read from their interfaces. *)
let add_interfaces units loadpath =
add_available_units
(List.map (fun unit -> (unit, digest_interface unit loadpath)) units)
(* Check whether the object file being loaded was compiled in unsafe mode *)
let unsafe_allowed = ref false
let allow_unsafe_modules b =
unsafe_allowed := b
let check_unsafe_module cu =
if (not !unsafe_allowed) && cu.cu_primitives <> []
then raise(Error(Unsafe_file))
(* Load in-core and execute a bytecode object file *)
let load_compunit ic file_name compunit =
check_consistency file_name compunit;
check_unsafe_module compunit;
seek_in ic compunit.cu_pos;
let code_size = compunit.cu_codesize + 8 in
let code = Meta.static_alloc code_size in
unsafe_really_input ic code 0 compunit.cu_codesize;
String.unsafe_set code compunit.cu_codesize (Char.chr Opcodes.opRETURN);
String.unsafe_set code (compunit.cu_codesize + 1) '\000';
String.unsafe_set code (compunit.cu_codesize + 2) '\000';
String.unsafe_set code (compunit.cu_codesize + 3) '\000';
String.unsafe_set code (compunit.cu_codesize + 4) '\001';
String.unsafe_set code (compunit.cu_codesize + 5) '\000';
String.unsafe_set code (compunit.cu_codesize + 6) '\000';
String.unsafe_set code (compunit.cu_codesize + 7) '\000';
let initial_symtable = Symtable.current_state() in
begin try
Symtable.patch_object code compunit.cu_reloc;
Symtable.check_global_initialized compunit.cu_reloc;
Symtable.update_global_table()
with Symtable.Error error ->
let new_error =
match error with
Symtable.Undefined_global s -> Undefined_global s
| Symtable.Unavailable_primitive s -> Unavailable_primitive s
| Symtable.Uninitialized_global s -> Uninitialized_global s
| _ -> assert false in
raise(Error(Linking_error (file_name, new_error)))
end;
begin try
ignore((Meta.reify_bytecode code code_size) ())
with exn ->
Symtable.restore_state initial_symtable;
raise exn
end
let loadfile file_name =
let ic = open_in_bin file_name in
try
let buffer = String.create (String.length Config.cmo_magic_number) in
really_input ic buffer 0 (String.length Config.cmo_magic_number);
if buffer = Config.cmo_magic_number then begin
let compunit_pos = input_binary_int ic in (* Go to descriptor *)
seek_in ic compunit_pos;
load_compunit ic file_name (input_value ic : compilation_unit)
end else
if buffer = Config.cma_magic_number then begin
let toc_pos = input_binary_int ic in (* Go to table of contents *)
seek_in ic toc_pos;
let lib = (input_value ic : library) in
begin try
Dll.open_dlls (List.map Dll.extract_dll_name lib.lib_dllibs)
with Failure reason ->
raise(Error(Cannot_open_dll reason))
end;
List.iter (load_compunit ic file_name) lib.lib_units
end else
raise(Error(Not_a_bytecode_file file_name));
close_in ic
with exc ->
close_in ic; raise exc
let loadfile_private file_name =
let initial_symtable = Symtable.current_state()
and initial_crc = !crc_interfaces in
try
loadfile file_name;
Symtable.hide_additions initial_symtable;
crc_interfaces := initial_crc
with exn ->
Symtable.hide_additions initial_symtable;
crc_interfaces := initial_crc;
raise exn
(* Error report *)
let error_message = function
Not_a_bytecode_file name ->
name ^ " is not a bytecode object file"
| Inconsistent_import name ->
"interface mismatch on " ^ name
| Unavailable_unit name ->
"no implementation available for " ^ name
| Unsafe_file ->
"this object file uses unsafe features"
| Linking_error (name, Undefined_global s) ->
"error while linking " ^ name ^ ".\n" ^
"Reference to undefined global `" ^ s ^ "'"
| Linking_error (name, Unavailable_primitive s) ->
"error while linking " ^ name ^ ".\n" ^
"The external function `" ^ s ^ "' is not available"
| Linking_error (name, Uninitialized_global s) ->
"error while linking " ^ name ^ ".\n" ^
"The module `" ^ s ^ "' is not yet initialized"
| Corrupted_interface name ->
"corrupted interface file " ^ name
| File_not_found name ->
"cannot find file " ^ name ^ " in search path"
| Cannot_open_dll reason ->
"error loading shared library: " ^ reason