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: (control_path_name,(exec_path_name*slice_name*Unix.file_descr) option) Hashtbl.t =
25 let receive_event (listening_socket_spec:fname_and_fd) (_:fname_and_fd) =
26 let (_,listening_socket) = listening_socket_spec in
28 let (data_socket, addr) = accept listening_socket in
34 Hashtbl.find unix_socket_table fname
35 with _ -> logprint "Received unexpected socket event from %s\n" fname;None in
37 | Some(execpath,slice_name,fd) ->
39 let child = fork () in
43 (* Close all fds except for the socket *)
44 ignore(execv execpath,[execpath]);
45 logprint "Could not execve %s" execpath
50 | _ -> logprint "Serious error! Got a non UNIX connection over a UNIX socket\n"
51 with e-> logprint "Error accepting socket\n"
53 (** Make a pair of fifo entries *)
54 let mkentry fqp exec_fqp perm slice_name =
55 logprint "Making control entry %s->%s\n" fqp exec_fqp;
56 let control_filename=sprintf "%s.control" fqp in
58 let listening_socket = socket PF_UNIX SOCK_STREAM 0 in
59 (try Unix.unlink control_filename with _ -> ());
60 let socket_address = ADDR_UNIX(control_filename) in
61 bind listening_socket socket_address;
62 listen listening_socket 10;
63 ( (* Make the user the owner of the pipes in a non-chroot environment *)
64 if (!Globals.nochroot) then
65 let pwentry = Unix.getpwnam slice_name in
66 Unix.chown control_filename pwentry.pw_uid pwentry.pw_gid
68 Hashtbl.replace unix_socket_table control_filename (Some(exec_fqp,slice_name,listening_socket));
69 Fdwatcher.add_fd (None,listening_socket) (None,listening_socket) receive_event;
72 e->logprint "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp exec_fqp;Failed
75 (** Close sockets that just got removed *)
77 let control_filename = String.concat "." [fqp;"control"] in
78 let entry = try Hashtbl.find unix_socket_table control_filename with Not_found -> None in
82 shutdown fd SHUTDOWN_ALL;
84 Hashtbl.remove unix_socket_table control_filename