1 (** unixsocketwathcer.ml: Routines to handle unix sockets for fd passing *)
2 (* Semantics for the client C, script S and Vsys, V
3 * - V creates a UNIX socket and listens on it, adding a watch
4 * - C connects to the socket
5 * - V accepts the connection, forks, execve()s S and gets out of the way
6 * - S sends an fd to C and closes the connection
7 * - If one of S or C dies, then the other gets a SIGPIPE, Vsys gets a sigchld,
8 * either way, Vsys should survive the transaction.
16 let close_if_open fd = (try (ignore(close fd);) with _ -> ())
18 type control_path_name = string
19 type exec_path_name = string
20 type slice_name = string
22 let unix_socket_table_fname: (control_path_name,Unix.file_descr option) Hashtbl.t =
25 let unix_socket_table_fd: (Unix.file_descr, (exec_path_name * slice_name) option) Hashtbl.t =
28 let receive_event (listening_socket_spec:fname_and_fd) (_:fname_and_fd) =
29 let (_,listening_socket) = listening_socket_spec in
31 let (data_socket, _) = accept listening_socket in
34 Hashtbl.find unix_socket_table_fd listening_socket
37 |None -> logprint "Received unexpected socket event\n";()
38 |Some (execpath, slice_name) ->
40 let child = fork () in
44 (* Close all fds except for the socket *)
45 let fd = Obj.magic data_socket in
49 if (i != fd) then close_if_open(Obj.magic i)
51 execv execpath [|execpath;slice_name;sprintf "%d" fd|] (*with
52 Unix_error(num,str1,str2)->logprint "Error %d: %s (%s)" (Obj.magic num) str1 str2;raise (Unix_error(num,str1,str2))*)
54 logprint "Could not execve %s" execpath
58 with e-> logprint "Error accepting socket\n"
60 (** Make a pair of fifo entries *)
61 let mkentry fqp exec_fqp perm slice_name =
62 logprint "Making control entry %s->%s\n" fqp exec_fqp;
63 let control_filename=sprintf "%s.control" fqp in
65 let listening_socket = socket PF_UNIX SOCK_STREAM 0 in
66 (try Unix.unlink control_filename with _ -> ());
67 let socket_address = ADDR_UNIX(control_filename) in
68 bind listening_socket socket_address;
69 listen listening_socket 10;
70 ( (* Make the user the owner of the pipes in a non-chroot environment *)
71 if (!Globals.nochroot) then
72 let pwentry = Unix.getpwnam slice_name in
73 Unix.chown control_filename pwentry.pw_uid pwentry.pw_gid
75 Hashtbl.replace unix_socket_table_fname control_filename (Some(listening_socket));
76 Hashtbl.replace unix_socket_table_fd listening_socket (Some(exec_fqp,slice_name));
77 Fdwatcher.add_fd (None,listening_socket) (None,listening_socket) receive_event;
80 e->logprint "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp exec_fqp;Failed
83 (** Close sockets that just got removed *)
85 let control_filename = String.concat "." [fqp;"control"] in
86 let entry = try Hashtbl.find unix_socket_table_fname control_filename with Not_found -> None in
90 Hashtbl.remove unix_socket_table_fd fd;
91 shutdown fd SHUTDOWN_ALL;
93 Hashtbl.remove unix_socket_table_fname control_filename