1 files changed, 83 insertions, 0 deletions
diff --git a/appl/alphabet/main/fd.b b/appl/alphabet/main/fd.b
new file mode 100644
index 00000000..11d10828
--- /dev/null
+++ b/appl/alphabet/main/fd.b
@@ -0,0 +1,83 @@
+implement Fd, Mainmodule;
+include "sys.m";
+	sys: Sys;
+include "draw.m";
+include "sh.m";
+include "alphabet/reports.m";
+	reports: Reports;
+		Report, report: import reports;
+include "alphabet.m";
+	alphabet: Alphabet;
+		Value: import alphabet;
+
+Fd: module {};
+
+typesig(): string
+{
+	return "ws";
+}
+
+init()
+{
+	sys = load Sys Sys->PATH;
+	alphabet = load Alphabet Alphabet->PATH;
+	reports = load Reports Reports->PATH;
+}
+
+quit()
+{
+}
+
+run(nil: ref Draw->Context, r: ref Reports->Report, errorc: chan of string,
+		nil: list of (int, list of ref Alphabet->Value),
+		args: list of ref Alphabet->Value): ref Alphabet->Value
+{
+	fd := sys->fildes(int (hd args).s().i);
+	if(fd == nil){
+		report(errorc, sys->sprint("error: no such file descriptor %q", (hd args).s().i));
+		return nil;
+	}
+	f := chan of ref Sys->FD;
+	spawn readfdproc(f, fd, r.start("stdin"));
+	return ref Value.Vw(f);
+}
+
+readfdproc(f: chan of ref Sys->FD, fd0: ref Sys->FD, errorc: chan of string)
+{
+	f <-= fd0;
+	fd1 := <-f;
+	if(fd1 == nil)
+		reports->quit(errorc);
+	wstream(fd0, fd1, errorc);
+	reports->quit(errorc);
+}
+
+wstream(fd0, fd1: ref Sys->FD, errorc: chan of string)
+{
+	sync := chan[2] of int;
+	qc := chan of int;
+	spawn stream(fd0, fd1, sync, qc, errorc);
+	spawn stream(fd1, fd0, sync, qc, errorc);
+	<-qc;
+	kill(<-sync);
+	kill(<-sync);
+}
+
+stream(fd0, fd1: ref Sys->FD, sync, qc: chan of int, errorc: chan of string)
+{
+	sync <-= sys->pctl(0, nil);
+	buf := array[Sys->ATOMICIO] of byte;
+	while((n := sys->read(fd0, buf, len buf)) > 0){
+		if(sys->write(fd1, buf, n) == -1){
+			report(errorc, sys->sprint("write error: %r"));
+			break;
+		}
+	}
+	qc <-= 1;
+	exit;
+}
+
+kill(pid: int)
+{
+	sys->fprint(sys->open("#p/"+string pid+"/ctl", Sys->OWRITE), "kill");
+}