Message passing / mail system

ce/Makefile

@@ -1,5 +1,6 @@
 include ../make/ufuncs.mk
 
 $(eval $(call add_lib,libstring))
+$(eval $(call add_lib,libprocess))
 
 include ../make/user.mk

ce/ce.c

@@ -1,4 +1,14 @@
-#include <m/system.h>
+#include <process.h>
 #include <string.h>
 
-void app_main (void) {}
+void app_main (void) {
+  int e_pid = get_exec_pid ();
+  int e_pgid = get_procgroup (e_pid);
+
+  for (;;) {
+    char ch;
+
+    mail_receive (&ch, 1);
+    mail_send (e_pgid, &ch, 1);
+  }
+}