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 uname =
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 uname in
38 Unix.chown control_filename pwentry.pw_uid pwentry.pw_gid
40 Hashtbl.replace unix_socket_table control_file (Some(exec_fqp,slice_name,listening_socket));
43 e->logprint "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp fifoout;Failed
45 (** Close sockets that just got removed *)
47 let control_filename = String.concat "." [fqp;"control"] in
48 let entry = try Hashtbl.find direct_fifo_table control_filename with Not_found -> None in
52 shutdown fd SHUTDOWN_ALL;
54 Hashtbl.remove unix_socket_table control_filename
56 (* vsys is activated when a client opens an in file *)
57 let connect_file fqp_in =
58 (* Do we care about this file? *)
60 Hashtbl.find direct_fifo_table fqp_in with _ -> None in
62 | Some(_,execpath,slice_name,fifo_fdin) ->
64 let len = String.length fqp_in in
65 let fqp = String.sub fqp_in 0 (len-3) in
66 let fqp_out = String.concat "." [fqp;"out"] in
68 try openfile fqp_out [O_WRONLY;O_NONBLOCK] 0o777 with
69 _-> (* The client is opening the descriptor too fast *)
70 sleep 1;try openfile fqp_out [O_WRONLY;O_NONBLOCK] 0o777 with
72 logprint "%s Output pipe not open, using stdout in place of %s\n" slice_name fqp_out;stdout
74 ignore(sigprocmask SIG_BLOCK [Sys.sigchld]);
76 clear_nonblock fifo_fdin;
77 let pid=try Some(create_process execpath [|execpath;slice_name|] fifo_fdin fifo_fdout fifo_fdout) with e -> None in
80 if (fifo_fdout <> stdout) then close_if_open fifo_fdout;
81 Hashtbl.add pidmap pid (fqp_in,fifo_fdout)
82 | None ->logprint "Error executing service: %s\n" execpath;reopenentry fqp_in
84 ignore(sigprocmask SIG_UNBLOCK [Sys.sigchld]);