1 (** directfifowatcher.ml: Routines to handle non-persistent scripts *)
3 * - The 'out' descriptor must be opened first
4 * - As soon as the backend script dies, the connection to the entry is
6 * - To avoid user-inflicted pain, all entries are opened at the time
7 * that they are created. Reopening these entries is a little complicated
8 * but nevertheless sound:
9 * * When a script dies, its fd is reopened
10 * * If a script fails to execute, its fd is closed and reopened to
11 * beat a race that can happen when the user closes the connection
12 * before the script can be launched.
22 let close_if_open fd = (try (ignore(close fd);) with _ -> ())
24 type in_pathname = string
25 type directory = string
26 type base_pathname = string
27 type slice_name = string
30 let direct_fifo_table: (in_pathname,(directory*base_pathname*slice_name*Unix.file_descr) option) Hashtbl.t =
33 let pidmap: (int,in_pathname * Unix.file_descr) Hashtbl.t = Hashtbl.create 1024
35 let rec list_check lst elt =
38 | car::cdr -> if (car==elt) then true else list_check cdr elt
40 let openentry_int fifoin =
42 try openfile fifoin [O_RDONLY;O_NONBLOCK] 0o777 with
43 e->logprint "Error opening and connecting FIFO: %s,%o\n" fifoin 0o777;raise e
47 (** Open entry safely, by first masking out the file to be opened *)
48 let openentry_safe root_dir fqp_in backend_spec =
49 Dirwatcher.mask_watch fqp_in;
50 let fd_in = openentry_int fqp_in in
51 let (fqp,slice_name) = backend_spec in
52 Hashtbl.replace direct_fifo_table fqp_in (Some(root_dir,fqp,slice_name,fd_in))
54 let openentry root_dir fqp backend_spec =
55 let fqp_in = String.concat "." [fqp;"in"] in
56 openentry_safe root_dir fqp_in backend_spec
58 let reopenentry fifoin =
59 let entry = try Hashtbl.find direct_fifo_table fifoin with _ -> None in
61 | Some(dir, fqp,slice_name,fd) -> close_if_open fd;openentry_safe dir fifoin (fqp,slice_name)
64 (* vsys is activated when a client opens an in file *)
65 let connect_file fqp_in =
66 (* Do we care about this file? *)
68 Hashtbl.find direct_fifo_table fqp_in with _ -> None in
70 | Some(_,execpath,slice_name,fifo_fdin) ->
71 (*fprintf logfd "Executing %s for slice %s\n" execpath
72 * slice_name;flush logfd;*)
74 let len = String.length fqp_in in
75 let fqp = String.sub fqp_in 0 (len-3) in
76 let fqp_out = String.concat "." [fqp;"out"] in
78 try openfile fqp_out [O_WRONLY;O_NONBLOCK] 0o777 with
79 _->logprint "%s Output pipe not open, using stdout in place of %s\n" slice_name fqp_out;stdout
81 ignore(sigprocmask SIG_BLOCK [Sys.sigchld]);
83 clear_nonblock fifo_fdin;
84 let pid=try Some(create_process execpath [|execpath;slice_name|] fifo_fdin fifo_fdout fifo_fdout) with e -> None in
87 if (fifo_fdout <> stdout) then close_if_open fifo_fdout;
88 Hashtbl.add pidmap pid (fqp_in,fifo_fdout)
89 | None ->logprint "Error executing service: %s\n" execpath;reopenentry fqp_in
91 ignore(sigprocmask SIG_UNBLOCK [Sys.sigchld]);
96 (** Make a pair of fifo entries *)
97 let mkentry fqp abspath perm uname =
98 logprint "Making entry %s->%s\n" fqp abspath;
99 let fifoin=sprintf "%s.in" fqp in
100 let fifoout=sprintf "%s.out" fqp in
101 (try Unix.unlink fifoin with _ -> ());
102 (try Unix.unlink fifoout with _ -> ());
104 let infname =(sprintf "%s.in" fqp) in
105 let outfname =(sprintf "%s.out" fqp) in
106 Unix.mkfifo infname 0o666;
107 Unix.mkfifo outfname 0o666;
108 ( (* Make the user the owner of the pipes in a non-chroot environment *)
109 if (!Globals.nochroot) then
110 let pwentry = Unix.getpwnam uname in
111 Unix.chown infname pwentry.pw_uid pwentry.pw_gid;
112 Unix.chown outfname pwentry.pw_uid pwentry.pw_gid
116 e->logprint "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp fifoout;Failed)
119 (** Close fifos that just got removed *)
121 let fqp_in = String.concat "." [fqp;"in"] in
122 let entry = try Hashtbl.find direct_fifo_table fqp_in with Not_found -> None in
127 Hashtbl.remove direct_fifo_table fqp_in
129 let sigchld_handle s =
130 let pid,_=Unix.waitpid [Unix.WNOHANG] 0 in
132 let fqp_in,fd_out = Hashtbl.find pidmap pid in
139 let rec add_dir_watch fqp =
140 Dirwatcher.add_watch fqp [S_Open] direct_fifo_handler
142 direct_fifo_handler wd dirname evlist fname =
143 let is_event = list_check evlist in
144 if (is_event Open) then
145 let fqp_in = String.concat "/" [dirname;fname] in
148 let del_dir_watch fqp =
152 Sys.set_signal Sys.sigchld (Sys.Signal_handle sigchld_handle)