1 (** fifowatcher.ml: Routines for creating and managing fifos *)
9 (** A connected process, FIFO *)
10 type channel_pipe = Process of out_channel | Fifo of out_channel | BrokenPipe
11 (** Signed file descriptors. Usually, we'll make sure that they're not
13 type signed_fd = Infd of Unix.file_descr | Outfd of Unix.file_descr | Eventfd of Unix.file_descr
15 let fdmap: (Unix.file_descr,string*string) Hashtbl.t = Hashtbl.create 1024
16 (** Maps pids to slice connections. Needed to clean up fds when a script dies
18 let pidmap: (int,signed_fd list) Hashtbl.t = Hashtbl.create 1024
19 let backend_prefix = ref ""
20 let open_fds: (Unix.file_descr,channel_pipe) Hashtbl.t = Hashtbl.create 1024
23 (** Receive an event from a running script. This event must be relayed to the
24 slice that invoked it.
26 @param idesc fd/fname identifier for process
28 let receive_process_event (idesc: fname_and_fd) (_: fname_and_fd) =
29 let (_,ifd) = idesc in
30 let cp = try Hashtbl.find open_fds ifd with
32 printf "Fifo fd disappeared\n";flush Pervasives.stdout;raise Bug
35 | Fifo(fifo_outchan) ->
36 let process_inchan = in_channel_of_descr ifd in
37 let cont = ref true in
40 let curline = input_line process_inchan in
41 fprintf fifo_outchan "%s\n" curline;flush fifo_outchan
43 | End_of_file|Sys_blocked_io|Unix_error(EPIPE,_,_)|Unix_error(EBADF,_,_) ->
47 | Unix_error(_,s1,s2) -> printf "Unix error %s - %s\n" s1 s2;flush Pervasives.stdout;cont:=false
48 | Sys_error(s) -> (* We get this error if the EPIPE comes before the EOF marker*) cont:=false
49 | e -> printf "Error - received unexpected event from file system !!!\n";raise e
51 | _ -> printf "Bug! Process fd received in the channel handler\n";flush Pervasives.stdout;raise Bug
54 let rec openentry_int fifoin fifoout (abspath:string*string) =
56 try openfile fifoin [O_RDONLY;O_NONBLOCK] 0o777 with
57 e->printf "Error opening and connecting FIFO: %s,%o\n" fifoin 0o777;flush Pervasives.stdout;raise e
59 Hashtbl.replace fdmap fdin abspath;
60 Fdwatcher.add_fd (Some(fifoin),fdin) (Some(fifoout),stdout) receive_fifo_event
61 and reopenentry_int fdin fifoin fifoout =
63 Fdwatcher.del_fd fdin;
65 Hashtbl.find fdmap fdin with _ -> printf "Bug: Phantom pipe\n";flush Pervasives.stdout;raise Bug
67 openentry_int fifoin fifoout abspath
68 (** receive an event from a fifo and connect to the corresponding service, or to
69 create it if it doesn't exit
70 @param eventdescriptor Name of input pipe,in descriptor
71 @param outdescriptor Name of output pipe, out descriptor
73 and receive_fifo_event eventdescriptor outdescriptor =
74 let (evfname,evfd) = eventdescriptor in
75 let (fname_other,fd_other) = outdescriptor in
76 (* Open the output pipe, or use stdout instead *)
78 match (fname_other) with
81 try openfile str [O_WRONLY;O_NONBLOCK] 0o777 with
82 _->printf "Output pipe not open, using stdout in place of %s\n" str;flush Pervasives.stdout;stdout
84 | None-> printf "Bug, nameless pipe\n";flush Pervasives.stdout;raise Bug
86 (* Check if the input descriptor is already registered (=> a session is open).
87 If not, register it and start a new session.*)
88 let pipe = try Hashtbl.find open_fds evfd with
90 (* Ok, need to launch script *)
91 let execpath,slice_name = Hashtbl.find fdmap evfd in
92 let (script_infd,pout) = Unix.pipe () in
93 let (pin,script_outfd) = Unix.pipe () in
94 set_nonblock script_infd;
95 let rpid = try Some(create_process execpath [|execpath;slice_name|] pin pout pout) with e -> printf "Error executing service: %s\n" execpath;flush Pervasives.stdout;None
100 (* Register fds associated with pid so that they can be cleaned up
102 Hashtbl.add pidmap pid [Infd(script_infd);Outfd(script_outfd);Eventfd(evfd)];
104 (* Connect pipe to running script *)
105 Hashtbl.add open_fds evfd (Process(out_channel_of_descr script_outfd));
107 (* Connect the running script to the pipe *)
108 Hashtbl.add open_fds script_infd (Fifo(out_channel_of_descr outfd));
110 (* Activate running script *)
111 Fdwatcher.add_fd (None,script_infd) (None,script_infd) receive_process_event;
113 (Process(out_channel_of_descr script_outfd))
115 (* We have the connection to the process - because it was open, or because it
116 just got established *)
117 let inchan_fd = in_channel_of_descr evfd in
119 | Process(out_channel) ->
120 let cont = ref true in
123 printf "Reading...\n";flush Pervasives.stdout;
124 let curline = input_line inchan_fd in
125 fprintf out_channel "%s\n" curline;flush out_channel
129 match (evfname,fname_other) with
130 | Some(str1),Some(str2)->
131 printf "Reopening entry\n";flush Pervasives.stdout;
132 reopenentry_int evfd str1 str2
134 printf "Bug, nameless pipe\n";flush Pervasives.stdout;raise Bug
136 printf "Race condition -> user deleted file before closing it. Clever ploy, but won't work.\n";
137 flush Pervasives.stdout
140 |Sys_blocked_io ->printf "Sysblockedio\n";flush Pervasives.stdout;
142 | _ ->printf "Bug: unhandled exception\n";flush Pervasives.stdout;raise Bug
145 | Fifo(_) -> printf "BUG! received process event from fifo\n";raise Bug
148 (** Make a pair of fifo entries *)
149 let mkentry fqp abspath perm uname =
150 printf "Making entry %s->%s\n" fqp abspath;flush Pervasives.stdout;
151 let fifoin=sprintf "%s.in" fqp in
152 let fifoout=sprintf "%s.out" fqp in
153 (try Unix.unlink fifoin with _ -> ());
154 (try Unix.unlink fifoout with _ -> ());
156 let infname =(sprintf "%s.in" fqp) in
157 let outfname =(sprintf "%s.out" fqp) in
158 Unix.mkfifo infname 0o666;
159 Unix.mkfifo outfname 0o666;
160 ( (* Make the user the owner of the pipes in a non-chroot environment *)
161 if (!Globals.nochroot) then
162 let pwentry = Unix.getpwnam uname in
163 Unix.chown infname pwentry.pw_uid pwentry.pw_gid;
164 Unix.chown outfname pwentry.pw_uid pwentry.pw_gid
168 e->printf "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp fifoout;flush Pervasives.stdout;Failed)
170 (** Open fifos for a session. Will shutdown vsys if the fifos don't exist *)
171 let openentry fqp abspath perm =
172 let fifoin = String.concat "." [fqp;"in"] in
173 let fifoout = String.concat "." [fqp;"out"] in
174 openentry_int fifoin fifoout abspath
176 let sigchld_handle s =
177 let pid,_=Unix.waitpid [Unix.WNOHANG] 0 in
179 let sfd_list = Hashtbl.find pidmap pid in
188 Hashtbl.remove open_fds fd (* Disconnect pipe *)
190 List.iter handle_sfd sfd_list;
191 Hashtbl.remove pidmap pid
193 Not_found-> (* Do nothing, probably a grandchild *)
197 Sys.set_signal Sys.sigchld (Sys.Signal_handle sigchld_handle)