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|
(** server.ml
*
* PDB server main loop
*
* @author copyright (c) 2005 alex ho
* @see <www.cl.cam.ac.uk/netos/pdb> pervasive debugger
* @version 1
*)
open Unix
open Buffer
(**
* connection_t: The state for each connection.
* buffer & length contains bytes that have been read from the sock
* but not yet parsed / processed.
*)
type connection_t =
{
fd : file_descr;
mutable buffer : string;
mutable length : int;
}
(**
* validate_checksum: Compute and compare the checksum of a string
* against the provided checksum using the gdb serial protocol algorithm.
*
*)
let validate_checksum command checksum =
let c0 = ref 0 in
for loop = 0 to (String.length command - 1) do
c0 := !c0 + int_of_char(command.[loop]);
done;
if (String.length checksum) = 2
then
let c1 = Util.int_of_hexchar(checksum.[1]) +
Util.int_of_hexchar(checksum.[0]) * 16 in
(!c0 mod 256) = (c1 mod 256)
else
false
(**
* process_input: Oh, joy! Someone sent us a message. Let's open the
* envelope and see what they have to say.
*
* This function is a paradigm of inefficiency; it performs as many
* string copies as possible.
*)
let process_input conn sock =
let max_buffer_size = 1024 in
let in_string = String.create max_buffer_size in
let length = read sock in_string 0 max_buffer_size in
conn.buffer <- conn.buffer ^ (String.sub in_string 0 length);
conn.length <- conn.length + length;
let re = Str.regexp "[^\\$]*\\$\\([^#]*\\)#\\(..\\)" in
begin
try
let break = String.index conn.buffer '\003' + 1 in
print_endline (Printf.sprintf "{{%s}}" (String.escaped conn.buffer));
(* discard everything seen before the ctrl-c *)
conn.buffer <- String.sub conn.buffer break (conn.length - break);
conn.length <- conn.length - break;
(* pause the target *)
PDB.pause (PDB.find_context sock);
(* send a code back to the debugger *)
Util.send_reply sock "S05"
with
Not_found -> ()
end;
(* with gdb this is unlikely to loop since you ack each packet *)
while ( Str.string_match re conn.buffer 0 ) do
let command = Str.matched_group 1 conn.buffer in
let checksum = Str.matched_group 2 conn.buffer in
let match_end = Str.group_end 2 in
begin
match validate_checksum command checksum with
| true ->
begin
Util.write_character sock '+';
try
let reply = Debugger.process_command command sock in
print_endline (Printf.sprintf "[%s] %s -> \"%s\""
(Util.get_connection_info sock)
(String.escaped command)
(String.escaped reply));
Util.send_reply sock reply
with
Debugger.No_reply ->
print_endline (Printf.sprintf "[%s] %s -> null"
(Util.get_connection_info sock)
(String.escaped command))
end
| false ->
Util.write_character sock '-';
end;
conn.buffer <- String.sub conn.buffer match_end (conn.length - match_end);
conn.length <- conn.length - match_end;
done;
if length = 0 then raise End_of_file
(** main_server_loop.
*
* connection_hash is a hash (duh!) with one connection_t for each
* open connection.
*
* in_list is a list of active sockets. it also contains two
* magic entries: server_sock for accepting new entries and
* event_sock for Xen event channel asynchronous notifications.
*)
let main_server_loop sockaddr =
let connection_hash = Hashtbl.create 10
in
let process_socket svr_sock sockets sock =
let (new_list, closed_list) = sockets in
if sock == svr_sock
then
begin
let (new_sock, caller) = accept sock in
print_endline (Printf.sprintf "[%s] new connection from %s"
(Util.get_connection_info sock)
(Util.get_connection_info new_sock));
Hashtbl.add connection_hash new_sock
{fd=new_sock; buffer=""; length = 0};
PDB.add_default_context new_sock;
(new_sock :: new_list, closed_list)
end
else
begin
try
match PDB.find_context sock with
| PDB.Event_channel ->
print_endline (Printf.sprintf "[%s] event channel"
(Util.get_connection_info sock));
Debugger.process_evtchn sock;
(new_list, closed_list)
| _ ->
let conn = Hashtbl.find connection_hash sock in
process_input conn sock;
(new_list, closed_list)
with
| Not_found ->
print_endline "error: (main_svr_loop) context not found";
PDB.debug_contexts ();
raise Not_found
| End_of_file ->
print_endline (Printf.sprintf "[%s] close connection from %s"
(Util.get_connection_info sock)
(Util.get_connection_info sock));
PDB.delete_context sock;
Hashtbl.remove connection_hash sock;
close sock;
(new_list, sock :: closed_list)
end
in
let rec helper in_list server_sock =
(*
* List.iter (fun x->Printf.printf "{%s} "
* (Util.get_connection_info x)) in_list;
* Printf.printf "\n";
*)
let (rd_list, _, _) = select in_list [] [] (-1.0) in
let (new_list, closed_list) = List.fold_left (process_socket server_sock)
([],[]) rd_list in
let merge_list = Util.list_remove (new_list @ in_list) closed_list in
helper merge_list server_sock
in
try
let server_sock = socket (domain_of_sockaddr sockaddr) SOCK_STREAM 0 in
setsockopt server_sock SO_REUSEADDR true;
bind server_sock sockaddr;
listen server_sock 2;
PDB.open_debugger ();
let event_sock = Evtchn.setup () in
PDB.add_context event_sock "event channel" [];
helper [server_sock; event_sock] server_sock
with
| Sys.Break ->
print_endline "break: cleaning up";
PDB.close_debugger ();
Hashtbl.iter (fun sock conn -> close sock) connection_hash
| Unix_error(e,err,param) ->
Printf.printf "unix error: [%s][%s][%s]\n" (error_message e) err param
| Sys_error s -> Printf.printf "sys error: [%s]\n" s
| Failure s -> Printf.printf "failure: [%s]\n" s
| End_of_file -> Printf.printf "end of file\n"
let get_port () =
if (Array.length Sys.argv) = 2
then
int_of_string Sys.argv.(1)
else
begin
print_endline (Printf.sprintf "syntax error: %s <port>" Sys.argv.(0));
exit 1
end
let main =
let address = inet_addr_any in
let port = get_port () in
main_server_loop (ADDR_INET(address, port))
|
