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 slice_name = string
21 let unix_socket_table: (control_path_name,Unix.file_descr option) Hashtbl.t =
24 let list_check lst elt _ =
25 let rec list_check_rec lst =
36 let openentry_int fifoin =
38 try openfile fifoin [O_RDONLY;O_NONBLOCK] 0o777 with
39 e->logprint "Error opening and connecting FIFO: %s,%o\n" fifoin 0o777;raise e
43 (** Open entry safely, by first masking out the file to be opened *)
44 let openentry_safe root_dir fqp_in backend_spec =
45 let restore = move_gate fqp_in in
46 let fd_in = openentry_int restore in
47 move_ungate fqp_in restore;
48 let (fqp,slice_name) = backend_spec in
49 Hashtbl.replace direct_fifo_table fqp_in (Some(root_dir,fqp,slice_name,fd_in))
51 let openentry root_dir fqp backend_spec =
52 let control_file = String.concat "." [fqp;"control"] in
53 openentry_safe root_dir fqp_in backend_spec
55 let reopenentry fifoin =
56 let entry = try Hashtbl.find direct_fifo_table fifoin with _ -> None in
58 | Some(dir, fqp,slice_name,fd) -> close_if_open fd;openentry_safe dir fifoin (fqp,slice_name)
61 (* vsys is activated when a client opens an in file *)
62 let connect_file fqp_in =
63 (* Do we care about this file? *)
65 Hashtbl.find direct_fifo_table fqp_in with _ -> None in
67 | Some(_,execpath,slice_name,fifo_fdin) ->
69 let len = String.length fqp_in in
70 let fqp = String.sub fqp_in 0 (len-3) in
71 let fqp_out = String.concat "." [fqp;"out"] in
73 try openfile fqp_out [O_WRONLY;O_NONBLOCK] 0o777 with
74 _-> (* The client is opening the descriptor too fast *)
75 sleep 1;try openfile fqp_out [O_WRONLY;O_NONBLOCK] 0o777 with
77 logprint "%s Output pipe not open, using stdout in place of %s\n" slice_name fqp_out;stdout
79 ignore(sigprocmask SIG_BLOCK [Sys.sigchld]);
81 clear_nonblock fifo_fdin;
82 let pid=try Some(create_process execpath [|execpath;slice_name|] fifo_fdin fifo_fdout fifo_fdout) with e -> None in
85 if (fifo_fdout <> stdout) then close_if_open fifo_fdout;
86 Hashtbl.add pidmap pid (fqp_in,fifo_fdout)
87 | None ->logprint "Error executing service: %s\n" execpath;reopenentry fqp_in
89 ignore(sigprocmask SIG_UNBLOCK [Sys.sigchld]);
94 (** Make a pair of fifo entries *)
95 let mkentry fqp abspath perm uname =
96 logprint "Making control entry %s->%s\n" fqp abspath;
97 let control_filename=sprintf "%s.control" fqp in
99 let listening_socket = socket PF_UNIX SOCK_STREAM 0 in
100 (try Unix.unlink control_filename with _ -> ());
101 let socket_address = ADDR_UNIX(control_filename) in
102 bind listening_socket socket_address;
103 ( (* Make the user the owner of the pipes in a non-chroot environment *)
104 if (!Globals.nochroot) then
105 let pwentry = Unix.getpwnam uname in
106 Unix.chown control_filename pwentry.pw_uid pwentry.pw_gid
110 e->logprint "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp fifoout;Failed)
113 (** Close fifos that just got removed *)
115 let control_filename = String.concat "." [fqp;"control"] in
116 let entry = try Hashtbl.find direct_fifo_table control_filename with Not_found -> None in
120 shutdown fd SHUTDOWN_ALL;
123 let rec add_dir_watch fqp =
124 Dirwatcher.add_watch fqp [S_Open] direct_fifo_handler
126 direct_fifo_handler wd dirname evlist fname =
127 let is_event = list_check evlist in
128 if (is_event Open Attrib) then
129 let fqp_in = String.concat "/" [dirname;fname] in
132 let del_dir_watch fqp =
136 Sys.set_signal Sys.sigchld (Sys.Signal_handle sigchld_handle)