From 1ec55b98ed344d38a1980557cce89d4e980ba2b4 Mon Sep 17 00:00:00 2001
From: adamch <adamch>
Date: Tue, 11 Sep 2007 10:57:37 +0000
Subject: [PATCH] More verbose system error reporting

---
 exn.mlt  |  6 ++++--
 init.sig |  4 ++++
 init.sml | 30 ++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/exn.mlt b/exn.mlt
index c36e18a..b28705f 100644
--- a/exn.mlt
+++ b/exn.mlt
@@ -11,8 +11,10 @@
 <b>System error</b>: <% Web.html name %>
 <% | OS.SysErr (name, SOME syserr) => %>
 <b>System error</b>: <% Web.html name %>: <% Web.html (OS.errorName syserr) %>: <% Web.htmlNl (OS.errorMsg syserr) %>
-<% | IO.Io {name, function, ...} => %>
-<b>IO error</b>: <% Web.html name %> for <% Web.html function %>
+<% | IO.Io {name, function, cause, ...} => %>
+<b>IO error</b>: <% Web.html name %> for <% Web.html function %><br>
+<b>Cause</b>: <% Web.html (Init.explain cause) %><br>
+<b>Tokens</b>: <p><% Web.htmlNl (Init.tokens ()) %></p>
 <% | Init.C.Sql msg => %>
 <b>SQL</b>: <% Web.htmlNl msg %>
 <% | Init.Access msg => %>
diff --git a/init.sig b/init.sig
index 39fe4ac..5c98e17 100644
--- a/init.sig
+++ b/init.sig
@@ -54,4 +54,8 @@ signature INIT = sig
     val listNodes : unit -> node list
     val nodeName : int -> string
     val nodeDebian : int -> string
+
+    val explain : exn -> string
+    val tokens : unit -> string
+    val tokensForked : unit -> unit
 end
diff --git a/init.sml b/init.sml
index 4d55c90..22b27f6 100644
--- a/init.sml
+++ b/init.sml
@@ -203,4 +203,34 @@ fun nodeDebian id =
 	[debian] => C.stringFromSql debian
       | row => rowError ("nodeDebian", row)
 
+fun explain e =
+    case e of
+	OS.SysErr (name, sop) =>
+	"System error: " ^ name ^
+	(case sop of
+	     NONE => ""
+	   | SOME syserr => ": " ^ OS.errorName syserr ^ ": " ^ OS.errorMsg syserr)
+      | _ => "Unknown"
+
+fun tokens () =
+    let
+	val proc = Unix.execute ("/usr/bin/tokens", [])
+	val inf = Unix.textInstreamOf proc
+
+	fun reader acc =
+	    case TextIO.inputLine inf of
+		NONE => String.concat (rev acc)
+	      | SOME s => reader (s :: acc)
+    in
+	reader []
+	before (TextIO.closeIn inf;
+		ignore (Unix.reap proc))
+    end
+
+fun tokensForked () =
+    case Posix.Process.fork () of
+	NONE =>	(OS.Process.system "/usr/bin/tokens >/tmp/tokens.child";
+		 OS.Process.exit OS.Process.success)
+      | _ => ignore (OS.Process.system "/usr/bin/tokens >/tmp/tokens.parent")
+
 end
-- 
2.20.1