Racket extension for using tcsetattr() to induce raw mode

Makefile

@@ -0,0 +1,16 @@
+SYSTEM_LIBRARY_SUBPATH:=compiled/native/$(shell racket -e '(display (path->string (system-library-subpath)))')
+
+all: $(SYSTEM_LIBRARY_SUBPATH)/tty-raw-extension.so
+
+clean:
+	rm -rf compiled
+
+$(SYSTEM_LIBRARY_SUBPATH):
+	mkdir -p $@
+
+$(SYSTEM_LIBRARY_SUBPATH)/%.so: %.c $(SYSTEM_LIBRARY_SUBPATH)
+	mzc --xform $*.c
+	mzc --3m --cc $*.3m.c
+	mzc --3m --ld $@ $*_3m.o
+	rm -f $*.3m.c
+	rm -f $*_3m.o

test-raw.rkt

@@ -0,0 +1,15 @@
+#lang racket/base
+
+(require "tty-raw-extension")
+
+(define (main)
+  (tty-raw!)
+  (let loop ()
+    (define ch (read-byte))
+    (printf "Byte: ~v\015\012" ch)
+    ;;(flush-output)
+    (if (member ch '(4 8 127)) ;; EOF, C-h, DEL
+	(exit)
+	(loop))))
+
+(main)

tty-raw-extension.c

@@ -0,0 +1,76 @@
+/* PLT Racket extension for selecting "raw" TTY mode */
+
+#include "escheme.h"
+
+#include <stdio.h>
+#include <signal.h>
+#include <termios.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define STDIN_FD 0
+
+static int is_raw = 0;
+static struct termios saved;
+
+static int ttyraw(void) {
+  /* Based on the settings given in http://www.minek.com/files/unix_examples/raw.html */
+  struct termios t;
+
+  if (is_raw) return 0;
+
+  if (tcgetattr(STDIN_FD, &saved) < 0) return -1;
+  t = saved;
+
+  t.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+  t.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+  t.c_cflag &= ~(CSIZE | PARENB);
+  t.c_cflag |= CS8;
+  t.c_oflag &= ~(OPOST);
+  t.c_cc[VMIN] = 1;
+  t.c_cc[VTIME] = 0;
+
+  if (tcsetattr(STDIN_FD, TCSAFLUSH, &t) < 0) return -1;
+
+  is_raw = 1;
+  return 0;
+}
+	
+static int ttyrestore(void) {
+  if (!is_raw) return 0;
+
+  if (tcsetattr(STDIN_FD, TCSAFLUSH, &saved) < 0) return -1;
+
+  is_raw = 0;
+  return 0;
+}
+
+static Scheme_Object *sch_ttyraw(int argc, Scheme_Object **argv) {
+  return ttyraw() == 0 ? scheme_true : scheme_false;
+}
+
+static Scheme_Object *sch_ttyrestore(int argc, Scheme_Object **argv) {
+  return ttyrestore() == 0 ? scheme_true : scheme_false;
+}
+
+Scheme_Object *scheme_reload(Scheme_Env *env) {
+  Scheme_Env *mod_env;
+  mod_env = scheme_primitive_module(scheme_intern_symbol("tty-raw-extension"), env);
+  scheme_add_global("tty-raw!",
+		    scheme_make_prim_w_arity(sch_ttyraw, "tty-raw!", 0, 0),
+		    mod_env);
+  scheme_add_global("tty-restore!",
+		    scheme_make_prim_w_arity(sch_ttyrestore, "tty-restore!", 0, 0),
+		    mod_env);
+  scheme_finish_primitive_module(mod_env);
+  return scheme_void;
+}
+
+Scheme_Object *scheme_initialize(Scheme_Env *env) {
+  atexit(ttyrestore);
+  return scheme_reload(env);
+}
+
+Scheme_Object *scheme_module_name(void) {
+  return scheme_intern_symbol("tty-raw-extension");
+}