Trace syscall complete, kernel interface and userspace demo program

user/traced.c

@@ -0,0 +1,18 @@
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+#include "kernel/syscall.h"
+
+int
+main(int argc, char *argv[])
+{
+  trace(1 << SYS_open);
+  int fd;
+
+  if((fd = open(argv[1], 0)) < 0) {
+    fprintf(stderr, "Traced: cannot open %s\n", argv[1]);
+    exit(1);
+  }
+
+  exit(0);
+}

user/user.h

@@ -2,6 +2,9 @@
 
 #include "../kernel/types.h"
 
+#define stderr 2
+#define stdout 1
+
 struct stat;
 
 /**