From: ian <ian>
Date: Sun, 25 May 2008 20:35:55 +0000 (+0000)
Subject: wip multiplex - much better now, including some message changes
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=27b22e58ab09fbea2d5094eae094eeb5c62007d2;p=trains.git

wip multiplex - much better now, including some message changes
---

diff --git a/hostside/.cvsignore b/hostside/.cvsignore
index eb8ad25..c634ab7 100644
--- a/hostside/.cvsignore
+++ b/hostside/.cvsignore
@@ -21,5 +21,6 @@ record-l.[ch]
 record-y.[ch]
 +persist*
 +*.log
++realtime.stderr
 *+dflags.h
 *.new
diff --git a/hostside/README.commands b/hostside/README.commands
index 2fac063..7580a79 100644
--- a/hostside/README.commands
+++ b/hostside/README.commands
@@ -1,13 +1,20 @@
 Protocol over new hostside stdin and to multiplexer:
 
- U< ?...   means realtime prints that message without any ?
-           when reflected by multiplexer, one of - + &
-           is prepended, as follows
-                  -   result of command by another client
-                  +   result of command by us
-                  &   asynchronous
-           other prefixes
-		  =   related to this actual connection
+ U<   possibly-asynchronous messages from realtime
+ R<   ditto, but saved for replay too
+ S    messages to simulation log
+
+ C>   commands (reflected to other clients)
+ L>   commands implemented by multiplexer and not reflected to other clients
+ O<   framming output from commands
+
+Messages from the multiplexer to its clients are always prefixed
+with a relevance character, shown as ? below.  In messages from
+realtime, the ? is absent.  ? may be
+      -   result of command by another client
+      +   result of command by us
+      &   asynchronous, not related to a specific command
+      =   related to this actual multiplexer client connection
 
 ======================================================================
 
@@ -24,13 +31,13 @@ POSSIBLY-ASYNCHRONOUS REPORTING OF MESSAGES TO/FROM (MASTER) PIC
  U< ?picioh in toolong <byte> [<byte>...]
  U< ?picioh in msg     <byte> [<byte>...]
 
- U< ?picio out polarity <[<segment>[,...]]>	literal < and > bracket segs
+ R< ?picio out polarity <[<segment>[,...]]>	literal < and > bracket segs
  U< ?picio out unknown				data printed in assoc'd picioh
 
  U< ?picio in <messagename> [<objectnum>]
  U< ?picio out <messagename> [<objectnum>]
 
- U< ?picio in-info detect 0|1 <segment-name>	decoded `picio in detect[01]'
+ U< ?detect <segment-name> 0|1		decoded `picio in detect[01]'
 
  Suppression (see parse-proto-spec and realtime.c:serial_transmit)
 	nmra data	ping/pong	special in	other out
@@ -42,29 +49,32 @@ POSSIBLY-ASYNCHRONOUS REPORTING OF MESSAGES TO/FROM (MASTER) PIC
 
  U< ?resolving <some message about resolution algorithm>
 
- S< ?resolution inexplicable <segment>
- S< ?resolution mispositioned head|tail <train> <crush-ending-seg> <distance>
- S< ?resolution movpos-change-failed <segment>/<poscombname>
- S< ?resolution problems <number-of-problems>
+ R< ?resolution inexplicable <segment>
+ R< ?resolution mispositioned head|tail <train> <crush-ending-seg> <distance>
+ R< ?resolution movpos-change-failed <segment>/<poscombname>
+ R< ?resolution problems <number-of-problems>
 
- S< ?stastate <state>
+ R< ?stastate <state>
 
  U< ?warning <type>[ <arguments>] :  <warning message>
  U< ?warning watchdog : PIC watchdog timer triggered
  U< ?warning spurious <count> : spurious short circuit (fault) etc.
+ U< ?warning realtime-stopped SIG*|exit*|E*|... : <explanation>
+ U< ?warning realtime-stderr : <emsg>
+ U< ?warning realtime-stderr-unavailable : <emsg>
 
  U< ?train <train> signalling-problem ....
  U< ?train <train> signalling-problem <problematic-segment> : <message>
 
- S< ?train <train> forwards|backwards at [-]<segment>:<maxinto>+-<uncertainty>
- S< ?train <train> has <markchar>[-]<segment>[/<movposcomb>]....
+ R< ?train <train> at [-]<segment>:<maxinto>+-<uncertainty> forwards|backwards
+ R< ?train <train> has <markchar>[-]<segment>[/<movposcomb>]....
        <markchar> is * for det_expected
                      ! for foredetect
                      @ for det_ignore
 
- S< ?movpos <segment> feat <feat><posn> point|relay
- S< ?movpos <segment> position <overallposn> moving
- S< ?movpos <segment> position <overallposn> stable
+ R< ?movpos <segment> feat <feat><posn> point|relay
+ R< ?movpos <segment> position <overallposn> moving
+ R< ?movpos <segment> position <overallposn> stable
             <overallposn> may be ? for unknown
 
  U< ?debug <context> : <debug message>
@@ -72,27 +82,27 @@ POSSIBLY-ASYNCHRONOUS REPORTING OF MESSAGES TO/FROM (MASTER) PIC
 
 MESSAGES TO SIMULATION LOG
 
- L  picioh in suppressed <byte> [<byte>...]
- L  picioh in suppressed-detect <byte> [<byte>...]
- L  command-in <command> <args>....
- L  timestamp <seconds>.<microseconds>
- L  timer-event <class>.<instance>
- L  0|1                   detection, same segment as last suppressed-detect
+ S  picioh in suppressed <byte> [<byte>...]
+ S  picioh in suppressed-detect <byte> [<byte>...]
+ S  command-in <command> <args>....
+ S  timestamp <seconds>.<microseconds>
+ S  timer-event <class>.<instance>
+ S  0|1                   detection, same segment as last suppressed-detect
 
 ======================================================================
 
 COMMANDS AND RESPONSES
 
- P> <command> [<arguments>...]
+ C> <command> [<arguments>...]
   results in:
- R< ?nak unknown-command|permission-denied|invalid-syntax [: <message...>]
- R< ?executing <command>
+ O< ?nak <errorcode> [<remaining info>] [: <message...>]
+ O< ?executing <command> [<arguments>...]
   consequential messages including picio, signalling problems etc.
-  then one of these
- R< ?ack <command> ok
- R< ?ack <command> <errorcode>
- R< ?ack <command> <errorcode> [<remaining info>] : <remaining error msg>...
- R< ?ack <command> <errorcode> SignallingPredictedProblem \
+  which may be U< R< then one of these
+ O< ?ack <command> ok
+ O< ?ack <command> <errorcode>
+ O< ?ack <command> <errorcode> [<remaining info>] : <remaining error msg>...
+ O< ?ack <command> <errorcode> SignallingPredictedProblem \
           <problematic-train> <problematic-segment>|? : <error message>...
 
     when these come through the multiplexer, everything which is a
@@ -107,18 +117,17 @@ COMMANDS AND RESPONSES
 
 MULTIPLEXER FACILITIES
 
- M< =  indicates messages from the multiplexer about this
- M> =   specific client connection
-
- M< =connected
- M< =permission normal|super
-  or
- M< =denied
+ U< =connected                           } on
+ U< =permission normal|super             } initial
+  or                                     }  connection
+ U< =denied                              }
   and later perhaps
- A< =failed : <message>           regardless of selected message patterns
-  otherwise there is no need to quit - just send eof
+ U< =failed : <message>              } regardless of
+ U< =failed client-io : <message>    }   selected message patterns
+                                     }  and then connection closed
+  There is no need to ask to quit - just send eof
 
- M> select [~]<pattern>...
+ L> select [~]<pattern>...
     first match wins; ~ discards the message.
     in pattern
         -+./:0-9a-zA-Z   match themselves
@@ -129,19 +138,20 @@ MULTIPLEXER FACILITIES
     if no match, it is as if the following patterns were appended
        ?info ?warning ~-* ~&* ~+debug *
 
- M> replay [~]<glob-pattern>...
- M< +executing replay
- M< <all saved messages, ie those marked with S< above>
- M< +ack replay ok
+ L> replay [[~]<glob-pattern>...]     if none, uses result from select
+ O< +executing replay
+ R< +<all messages saved for replay, ie those marked with R< above,
+      matching the patterns, all of which will be prefixed with + this time>
+ O< +ack replay ok
 
 
 MULTIPLEXER-IMPLEMENTED FUNCTIONALITY AFFECTING WHOLE SYSTEM
 
- P> [!]<command> <args>...
- R< ?nak|executing...ack...  as above
+ C> [!]<command> <args>...
+ O< ?nak|executing...ack...  as above
 
- C> !realtime kill|finish|start|start-manual
- C> !save
+ C> !realtime kill|start|start-manual
+ C> !dump
 
 
 ======================================================================
@@ -149,20 +159,20 @@ MULTIPLEXER-IMPLEMENTED FUNCTIONALITY AFFECTING WHOLE SYSTEM
 DIRECT NMRA AND PIC INSTRUCTIONS
 
                                             Example (always the same msg):
- P> !nmra [<slot>] [<nmra-command [<nmra-args>...]]    nmra speed28 3 13 1
- P> !nmra [<slot>] [=<nmra-bytes>]                     nmra =0348
- P> !nmra [<slot>] [:<nmra-bytes-with-csum>]           nmra :03484b
- P> !nmra [<slot>] [_<pic-literal-bytes>]              nmra _7f7f00644197
+ C> !nmra [<slot>] [<nmra-command [<nmra-args>...]]    nmra speed28 3 13 1
+ C> !nmra [<slot>] [=<nmra-bytes>]                     nmra =0348
+ C> !nmra [<slot>] [:<nmra-bytes-with-csum>]           nmra :03484b
+ C> !nmra [<slot>] [_<pic-literal-bytes>]              nmra _7f7f00644197
    in each case <slot> (if present) is *<slotname> or %<slotname> and
    indicates that the message should be put in the retransmission
    cycle, and cancels any previous message with the same <slotname>.
    <slotname> may be empty.  * indicates urgent
- P> !nmra <slot>
+ C> !nmra <slot>
    cancels the relevant retransmission.
 
                                             Example (always the same msg):
- P> !pic =<pic-bytes>                                   pic =a003
- P> !pic <pic-command> [<pic-args...>]                  pic point 3
+ C> !pic =<pic-bytes>                                   pic =a003
+ C> !pic <pic-command> [<pic-args...>]                  pic point 3
        the latter for commands with no `...' in README.protocol only
 
  Keen readers will observe that
diff --git a/hostside/commands.c b/hostside/commands.c
index 36386a0..0fcc7a2 100644
--- a/hostside/commands.c
+++ b/hostside/commands.c
@@ -307,19 +307,21 @@ static int cmd_invert(ParseState *ps, const CmdInfo *ci) {
  
 void command_doline(ParseState *ps, CommandInput *cmdi_arg) {
   int r;
+  const char *cmdline;
 
   simlog("command-in %s\n",ps->remain);
   simlog_flush();
   current_cmd= 0;
 
-  if (!ps->remain[0]) return;
+  cmdline= ps->remain;
+  if (!cmdline[0]) return;
   r= ps_word(ps);  assert(!r);
   current_cmd= some_lookup(ps,toplevel_cmds);
   if (!current_cmd) {
-    ouprintf("nack unknown-command\n");
+    ouprintf("nack UnknownCommand\n");
     return;
   }
-  ouprintf("executing %s\n",current_cmd->name);
+  ouprintf("executing %s\n",cmdline);
   if (sta_state < Sta_Run && !(current_cmd->xarg & CIXF_ANYSTA)) {
     ouprintf("ack %s InvalidState : layout not ready\n",current_cmd->name);
     return;
diff --git a/hostside/errorcodes.h.gen b/hostside/errorcodes.h.gen
index d2aaf5b..2eaf630 100755
--- a/hostside/errorcodes.h.gen
+++ b/hostside/errorcodes.h.gen
@@ -11,7 +11,12 @@
        InvalidState
        SignallingPredictedProblem
        SignallingHorizonReached
+
        LimitExceeded
+       SystemFailed
+       UnknownCommand
+       PermissionDenied
+       HostSupportSystemsProblem
        );
 
 
diff --git a/hostside/multiplex b/hostside/multiplex
index 6b8056f..5293905 100755
--- a/hostside/multiplex
+++ b/hostside/multiplex
@@ -1,18 +1,44 @@
-#!/usr/bin/tclsh8.4
+#!/usr/bin/tcl
 
 # per connection:
 #    c/$conn(super)          0 or 1
 #    c/$conn(ipaddr)
 #    [msel/$conn "$msg "]    0 or 1
+#    [mreplay/$conn "$msg "] 0 or 1 during replay only
+#    c/$conn(q)              [list $inputline ...]
 #
 # globals:
-#    $cmdqueue         [list $conn $cmd ...]
-#    $master           socket
-#    $permissions      [list allow|super|deny $ipaddrhex $maskhex ...]
-
-#---------- i/o to realtime ----------
+#    $queueing            [list $conn ...]
+#    $master              socket
+#    $permissions         [list allow|super|deny $ipaddrhex $maskhex ...]
+#    $realtime            pipes
+#    $replay("$pri $key") $rhs     $pri is \d\d; causes replay of  "$key $rhs"
+#    $detect0($seg)       unset -> 1 or irrelevant; [after ...]
+#    $conns($conn)        1
+#
+# configs set directly in multiplex-config:
+#    $records          [list filename.record ...]
+#    $detectlag        <ms>
+#
+# $conn is in $queueing iff c/$conn(q) is nonempty
+#
+# globals relating to realtime's command execution state:
+#                           awaiting        awaiting  executing global
+#                   idle     executing/nak   ack       internal cmd     dead
+#
+#    $realtime       set      set            set          ?             unset
+#    $currentcmd     unset    $cmd           $cmd         $cmd          unset
+#    $currentconn    unset    $conn or {}    $conn or {}  $conn         unset
+#    $executing      0        0              1            1             0
+#
+# replay priorities and messages:
+#    10 stastate
+#    50 resolution ....
+#    60 movpos ...
+#       train ...
+#    70 detect <seg> 0|1
 
-proc cmdqueue-check {args} { }
+#---------- replay, general utilities, etc. ----------
 
 proc compile-glob-patterns {pats procname} {
     if {[llength $pats] > 20 || [string length $pats] > 200} {
@@ -36,20 +62,107 @@ proc compile-glob-patterns {pats procname} {
     append def {    {^[-&]\S|^\+debug\s} { return 0 }} "\n"
     append def "    }\n"
     append def "    return 1\n"
-    puts $def
     proc $procname {m} $def
 }
 
-proc cmd/select {conn args} {
+proc nargs {l {n 0}} {
+    if {[llength $l]!=$n} { cmderr BadCmd "wrong number of arguments" }
+}
+
+proc xmit-relevantly {m} {
+    global executing currentconn conns
+    if {$executing} {
+	puts "<* $m"
+	set myconn $currentconn
+	trapping xmit-only-noreport $currentconn +$m
+	set othersm -$m
+    } else {
+	puts "<& $m"
+	set myconn {}
+	set othersm &$m
+    }
+    foreach conn [array names conns] {
+	if {[string compare $myconn $conn]} {
+	    trapping xmit-only-noreport $conn $othersm
+	}
+    }
+}
+
+#---------- multiplexer-implemented command ----------
+
+proc local/select {conn args} {
     upvar #0 c/$conn c
     compile-glob-patterns $args msel/$conn
 }
 
+proc global/!dump {conn args} {
+    nargs $args
+    if {[catch { save-dump } emsg]} {
+	cmderr HostSupportSystemsProblem "failed to save dump: $emsg"
+    }
+}
+
+proc local/replay {conn args} {
+    global replay
+    if {[llength $args]} {
+	rename msel/$conn mreplay/$conn ;# park it here for a moment
+	compile-glob-patterns $args msel/$conn
+    }
+    foreach pk [lsort [array names replay]] {
+	set m "+[string range $pk 3 end] $replay($pk)"
+	xmit-only $conn $m
+    }
+    if {[llength $args]} {
+	rename mreplay/$conn msel/$conn
+    }
+}
+
+proc global/!realtime {conn args} {
+    nargs $args 1
+    switch -exact [lindex $args 0] {
+	kill { realtime-failed killed "termination requested by command" }
+	start { realtime-start {} }
+	start-manual { realtime-start -m }
+	default { cmderr BadCmd "unknown !realtime subcommand" }
+    }
+}
+
 #---------- connection and commands ----------
 
 proc client-inputline {conn l} {
+    global queueing
+    upvar #0 c/$conn c
+    puts "$conn> $l"
+    client-disable-readable $conn
+    if {![llength $c(q)]} { lappend queueing $conn }
+    lappend c(q) $l
+    after idle process-queues
+}
+
+proc process-queues {} {
+    global queueing currentcmd
+    while {![info exists currentcmd] && [llength $queueing]} {
+	set conn [lindex $queueing 0]
+	set queueing [lrange $queueing 1 end]
+
+	upvar #0 c/$conn c
+	if {![llength $c(q)]} continue
+
+	set l [lindex $c(q) 0]
+	set c(q) [lrange $c(q) 1 end]
+	if {[llength $c(q)]} {
+	    lappend queueing $conn
+	} else {
+	    client-enable-readable $conn
+	}
+
+	trapping process-command $conn $l
+    }
+}
+
+proc process-command {conn l} {
+    global currentcmd currentconn realtime executing
     global errorInfo errorCode
-    global cmdqueue
     upvar #0 c/$conn c
     set cmd ?
     set r [catch {
@@ -57,35 +170,70 @@ proc client-inputline {conn l} {
 	set l [string trim $l]
 	if {![string length $l]} return
 	if {![regexp {^((!?)[-a-z0-9]+)(?:\s.*)?$} $l dummy cmd priv]} {
-	    error "improper command name" {} {TRAIN CMDNAK invalid-syntax}
+	    error "improper command name" {} {TRAIN CMDNAK BadCmd}
 	}
 	if {[regexp {[^ \t!-~]} $l]} {
-	    error "improper character" {} {TRAIN CMDNAK invalid-syntax}
+	    error "improper character" {} {TRAIN CMDNAK BadCmd}
 	}
 	if {[string length $priv] && !$c(super)} {
-	    error "" {} {TRAIN CMDNAK permission-denied}
+	    error "" {} {TRAIN CMDNAK PermissionDenied}
 	}
-	if {![catch { info args cmd/$cmd }]} {
-	    xmit $conn "+executing $cmd"
-	    eval [list cmd/$cmd $conn] [lrange [split $l] 1 end]
+
+	if {![catch { info args global/$cmd }]} {
+	    set currentcmd $cmd
+	    set currentconn $conn
+	    set executing 1
+	    xmit-relevantly "executing $cmd"
+	    eval [list global/$cmd $conn] [lrange [split $l] 1 end]
+	} elseif {![catch { info args local/$cmd }]} {
+	    xmit-only $conn "+executing $cmd"
+	    eval [list local/$cmd $conn] [lrange [split $l] 1 end]
+	} elseif {![info exists realtime]} {
+	    error "" {} {TRAIN CMDNAK realtime-not-running}
 	} else {
-	    lappend cmdqueue $conn $l
-	    after idle cmdqueue-check
+	    set currentcmd $cmd
+	    set currentconn $conn
+	    if {[catch {
+		puts ">> $l"
+		puts $realtime $l
+	    } emsg]} {
+		if {[string match {POSIX EPIPE *} $errorCode]} {
+		    realtime-failed EPIPE ""
+		} elseif {[string match {POSIX *} $errorCode]} {
+		    realtime-failed [lindex $errorCode 1] \
+			    "write failed: [lindex $errorCode 2]"
+		} else {
+		    realtime-failed ?write-[lindex $errorCode 0] \
+			    "puts failed ($errorCode): $emsg"
+		}
+	    }
+	    return
 	}
     } emsg]
     if {$r==2} return
-    if {$r==0} { xmit $conn "+ack $cmd ok"; return }
+    if {$r==0} {
+	set m "ack $cmd ok"
+	if {$executing} {
+	    xmit-relevantly $m
+	    set executing 0
+	    unset currentconn
+	    unset currentcmd
+	} else {
+	    xmit-only $conn +$m
+	}
+	return
+    }
     switch -glob $errorCode {
 	{TRAIN REPORTED*} {
 	}
 	{TRAIN CMDNAK*} {
 	    set el [concat [list +nack] [lrange $errorCode 2 end]]
 	    if {[string length $emsg]} { append el ": " $emsg }
-	    xmit $conn "$el"
+	    xmit-only $conn "$el"
 	}
 	{TRAIN CMDERR*} {
 	    set el [concat [list +ack $cmd] [lrange $errorCode 2 end]]
-	    xmit $conn "$el : $emsg"
+	    xmit-only $conn "$el : $emsg"
 	}
 	* {
 	    set ei $errorInfo; set ec $errorCode
@@ -95,7 +243,17 @@ proc client-inputline {conn l} {
     }
 }
 
-proc client-eof {conn} { kill-conn $conn "" }
+proc client-eof {conn} {
+    puts "$conn>\$"
+    kill-conn $conn ""
+}
+
+proc client-enable-readable {conn} {
+    fileevent $conn readable [list trapping readable client $conn]
+}
+proc client-disable-readable {conn} {
+    fileevent $conn readable {}
+}
 
 #---------- general IO ----------
 
@@ -104,26 +262,44 @@ proc readable {whatfor conn} {
     if {[eof $conn]} { $whatfor-eof $conn }
 }
 
-proc xmit-always {conn msg} { puts $conn $msg }
+proc xmit-puts {conn msg} {
+    global conns errorInfo
+    if {![info exists conns($conn)]} return
+    if {[catch { puts -nonewline $conn $msg } emsg]} {
+	kill-conn $conn "=failed client-io : $emsg"
+	error $emsg $errorInfo {TRAIN REPORTED}
+    }
+}
 
-proc xmit {conn msg} {
+proc xmit-only-always {conn msg} {
+    puts "<$conn $msg"
+    xmit-puts $conn "$msg\n"
+}
+proc xmit-only-noreport {conn msg} {
     append msg "\n"
-    if {[msel/$conn $msg]} { puts -nonewline $conn $msg }
+    if {[msel/$conn $msg]} { xmit-puts $conn $msg }
+}
+proc xmit-only {conn msg} {
+    puts "<$conn $msg"
+    xmit-only-noreport $conn $msg
 }
 
 #---------- error handling ----------
 
 proc kill-conn {conn msg} {
+    global conns queueing
     upvar #0 c/$conn c
-    global cmdqueue
-    if {[string length $msg]} { catch { xmit-always $conn $msg } }
+    catch { unset conns($conn) } ;# do this first to stop any recursion
+    puts "<$conn\$ closing : $msg"
+    if {[string length $msg]} { catch { xmit-only-always $conn "$msg" } }
     catch { close $conn }
+    if {[set ix [lsearch -exact $queueing $conn]] >= 0} {
+	set queueing [lreplace $queueing $ix $ix]
+    }
     catch { unset c }
     catch { rename msel/$conn {} }
+    catch { rename mreplay/$conn {} }
     set qn {}
-    foreach {tconn tl} $cmdqueue {
-	if {[string compare $tconn $tl]} { lappend qn $tconn $tl }
-    }
     set cmdqueue $qn
 }
 
@@ -154,7 +330,7 @@ proc trapping {proc conn args} {
     if {![catch { uplevel #0 [list $proc $conn] $args } r]} { return $r }
     switch -glob $errorCode {
 	{TRAIN EXPECTED*} { kill-conn $conn "=failed : $r" }
-	{TRAIN SILENT*} { kill-conn $conn }
+	{TRAIN REPORTED*} { kill-conn $conn "" }
 	* {
 	    report-unexpected {UNEXPECTED ERROR} $r
             kill-conn-ierr $conn
@@ -162,6 +338,164 @@ proc trapping {proc conn args} {
     }
 }	
 
+#---------- realtime subprocess ----------
+
+proc realtime-failed {k m} {
+    global realtime currentcmd currentconn executing
+    global errorInfo errorCode
+    # if $m is "", use wait status
+    if {![string length $m]} {
+	set r [catch {
+	    fconfigure $realtime -blocking 1
+	    close $realtime
+	} emsg]
+	if {!$r} {
+	    set m "unexpectedly closed pipe ?!"
+	    set k unexpected
+	} elseif {[string match {CHILDSTATUS*} $errorCode]} {
+	    set m "exited with status [lindex $errorCode 2]"
+	    set k "exit[lindex $errorCode 2]"
+	} elseif {[string match {CHILDKILLED*} $errorCode]} {
+	    set m "killed by signal [lindex $errorCode 3]"
+	    set k [lindex $errorCode 2]
+	} else {
+	    set m "failed confusingly ($errorCode): $emsg"
+	    set k ?wait-[lindex $errorCode 0]
+	}
+    } else {
+	catch { close $realtime }
+    }
+    puts "<<\$ $k : $m"
+    catch { unset realtime }
+    if {[catch {
+	set sef [open +realtime.stderr r]
+	while {[gets $sef l] >= 0} {
+	    xmit-relevantly "warning realtime-stderr : $l"
+	}
+	close $sef
+	unset sef
+    } emsg]} {
+	if {![string match {POSIX ENOENT *} $errorCode]} {
+	    xmit-relevantly "warning realtime-stderr-unreadable : $emsg"
+	}
+	catch { close $sef }
+    }
+    xmit-relevantly "warning realtime-stopped $k : $m"
+    if {[catch {
+	save-dump
+    } emsg]} {
+	xmit-relevantly "warning dump-failed : $emsg"
+    }
+    if {$executing} {
+	xmit-relevantly "ack $currentcmd SystemFailed realtime : $m"
+	set executing 0
+    } elseif {[info exists currentcmd]} {
+	xmit-relevantly "nak SystemFailed realtime : $m"
+	unset currentcmd
+	unset currentconn
+    }
+    realtime-notrunning-init
+}
+
+proc realtime-notrunning-init {} {
+    realtime-inputline dummy "stastate -" ;# fake this up
+}
+
+proc realtime-start {xopts} {
+    global realtime records
+    if {[info exists realtime]} {
+	cmderr InvalidState "realtime already running"
+    }
+    set cl [concat \
+	    [list 2> +realtime.stderr ./realtime -v2] \
+	    $xopts $records]
+    if {[catch {
+	set realtime [open |$cl r+]
+	fconfigure $realtime -translation binary -buffering line -blocking 0
+	fileevent $realtime readable [list readable realtime $realtime]
+    } emsg]} {
+	realtime-failed start $emsg
+	error "realtime failed : $emsg" "" {TRAIN REPORTED}
+    }
+}
+
+proc realtime-eof {dummy} { realtime-failed EOF "" }
+
+proc detect0timeout {seg} {
+    global replay
+    upvar #0 detect0($seg) d0
+    unset d0
+    set key "detect $seg"
+    set replay("70 $key") 0
+    xmit-relevantly "$key 0"
+}
+
+proc clear-replay-detects {} {
+    global replay
+    foreach k [array names replay] {
+	if {[regexp {^.. detect } $k]} { unset replay($k) }
+    }
+}
+
+proc realtime-inputline {dummy l} {
+    global detectlag replay
+
+    puts "<< $l"
+
+    if {[regexp {^(detect (\w+)) ([01])$} $l dummy key seg value]} {
+	upvar #0 detect0($seg) d0
+	catch { after cancel $d0 }
+	if {$value} {
+	    if {[info exists d0]} { unset d0; return }
+	} else {
+	    set d0 [after $detectlag detect0timeout $seg]
+	    return
+	}
+	set pri 70
+    } elseif {[regexp {^(stastate) (.*)$} $l dummy key value]} {
+	switch -exact -- $value {
+	    Settling { clear-replay-detects }
+	    Resolving { catch { unset replay("50 resolution") } }
+	}
+	set pri 10
+    } elseif {[regexp {^(resolution) (.*)$} $l dummy key addvalue]} {
+	set pri 50
+    } elseif {[regexp -expanded {
+	^( movpos \s \S+ \s (?: feat \s \S+ | position) |
+	   train  \s \S+ \s (?: has | at ) |
+	   picio  \s out \s polarity
+	) \s (.*) $
+              } $l dummy key value]} {
+        set pri 60
+    }
+    if {[info exists key]} {
+	set pk "$pri $key"
+	upvar #0 replay($pk) rep
+	if {[info exists value]} {
+	    set rep $value
+	} else {
+	    append rep $value
+	}
+    }
+
+    switch -regexp -- $l {
+	{^executing\s|^nak\s} {
+	    set executing 1
+	}
+    }
+
+    xmit-relevantly $l
+
+    switch -regexp -- $l {
+	{^ack\s|^nak\s} {
+	    set executing 0
+	    unset currentcmd
+	    unset currentconn
+	    after idle process-queues
+	}
+    }
+}
+
 #---------- new connections ----------
 
 proc find-permission {ipaddr} {
@@ -174,8 +508,11 @@ proc find-permission {ipaddr} {
 }
 
 proc connected {conn} {
+    global conns
     upvar #0 c/$conn c
     fconfigure $conn -blocking 0 -buffering none -translation auto
+    set c(q) {}
+    set conns($conn) 1
     set perm [find-permission $c(ipaddr)]
     switch -exact $perm {
 	deny { finally $conn =denied; return }
@@ -185,14 +522,15 @@ proc connected {conn} {
     }
     compile-glob-patterns {} msel/$conn
     
-    xmit-always $conn =connected
-    xmit-always $conn "=permission [lindex {normal super} $c(super)]"
-    fileevent $conn readable [list trapping readable client $conn]
+    xmit-only-always $conn =connected
+    xmit-only-always $conn "=permission [lindex {normal super} $c(super)]"
+    client-enable-readable $conn
 }
 
 proc newconn {conn ipaddr port} {
     upvar #0 c/$conn c
     catch { unset c }
+    puts "$conn new-client $conn $ipaddr $port"
     set c(ipaddr) $ipaddr
     trapping connected $conn
 }
@@ -240,10 +578,13 @@ proc binding {addr blist} {
 }
 
 proc startup {} {
-    global cmdqueue
+    global queueing executing
     catch { close $master }; catch { unset master }
-    source multiplex-config
-    set cmdqueue {}
+    uplevel #0 source multiplex-config
+    set queueing {}
+    set executing 0
+    realtime-notrunning-init
+    commandloop -async -prompt1 { return "% " } -prompt2 { return "> " }
 }
 
 startup
diff --git a/hostside/multiplex-config b/hostside/multiplex-config
index 13c47c4..4e87d3a 100644
--- a/hostside/multiplex-config
+++ b/hostside/multiplex-config
@@ -10,3 +10,8 @@ binding 127.0.0.1 {
 	super	127.0.0.1
 	deny	0.0.0.0/32
 }
+set records {
+	shinkansen.speeds.record
+	homes.record
+}
+set detectlag 100
diff --git a/hostside/safety.c b/hostside/safety.c
index fb0fd3f..e67f85a 100644
--- a/hostside/safety.c
+++ b/hostside/safety.c
@@ -965,10 +965,11 @@ ErrorCode predict(Train *tra, struct timeval tnow, unsigned flags,
 /*========== reporting position and ownership ==========*/
 
 void report_train_position(Train *tra) {
-  ouprintf("train %s %s at %s%s:%d+-%d\n",
-	   tra->pname, tra->backwards ? "backwards" : "forwards",
+  ouprintf("train %s at %s%s:%d+-%d %s\n",
+	   tra->pname,
 	   tra->foredetect->tr_backwards?"-":"",
-	   tra->foredetect->i->pname, tra->maxinto, tra->uncertainty);
+	   tra->foredetect->i->pname, tra->maxinto, tra->uncertainty,
+	   tra->backwards ? "backwards" : "forwards");
 }  
   
 static int report_getmovpos(TrackLocation *t, TrackAdvanceContext *c,
diff --git a/hostside/startup.c b/hostside/startup.c
index dd6fd0c..0cdc945 100644
--- a/hostside/startup.c
+++ b/hostside/startup.c
@@ -292,8 +292,7 @@ static SegmentNum on_pic_detect_prep(int detyn, int objnum) {
   if (!(picio_send_noise <= 1 &&
 	segments[segn].owner &&
 	segments[segn].det_ignore))
-    ouprintf_only("picio in-info detect %d %s\n",
-		  detyn, info_segments[segn].pname);
+    ouprintf_only("detect %s %d\n", info_segments[segn].pname, detyn);
 
   return segn;
 }