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 (** Make a pair of fifo entries *)
26 let mkentry fqp exec_fqp perm slice_name =
27 logprint "Making control entry %s->%s\n" fqp exec_fqp;
28 let control_filename=sprintf "%s.control" fqp in
30 let listening_socket = socket PF_UNIX SOCK_STREAM 0 in
31 (try Unix.unlink control_filename with _ -> ());
32 let socket_address = ADDR_UNIX(control_filename) in
33 bind listening_socket socket_address;
34 listen listening_socket 10;
35 ( (* Make the user the owner of the pipes in a non-chroot environment *)
36 if (!Globals.nochroot) then
37 let pwentry = Unix.getpwnam slice_name in
38 Unix.chown control_filename pwentry.pw_uid pwentry.pw_gid
40 Hashtbl.replace unix_socket_table control_filename (Some(exec_fqp,slice_name,listening_socket));
43 e->logprint "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp exec_fqp;Failed
45 let receive_event (listening_socket_spec:fname_and_fd) (_:fname_and_fd) =
46 let (_,listening_socket) = listening_socket_spec in
48 let (data_socket, addr) = accept listening_socket in
54 Hashtbl.find unix_socket_table fname
57 | Some(execpath,slice_name,fd) ->
59 let child = fork () in
63 (* Close all fds except for the socket *)
64 execv execpath,[execpath];
65 logprint "Could not execve %s" execpath
70 | _ -> logprint "Serious error! Got a non UNIX connection over a UNIX socket\n"
71 with e-> logprint "Error accepting socket\n"
73 (** Close sockets that just got removed *)
75 let control_filename = String.concat "." [fqp;"control"] in
76 let entry = try Hashtbl.find unix_socket_table control_filename with Not_found -> None in
80 shutdown fd SHUTDOWN_ALL;
82 Fdwatcher.add_fd (None,fd) (None,fd) receive_event;
83 Hashtbl.remove unix_socket_table control_filename