Finished adding untested bare functionality vfs

Finished adding untested shm syscalls.
Finished adding untested l4 send/recv helpers

Everything compiles. Now going to fix lots of bugs ;-)

tasks/fs0/src/file.c

@@ -0,0 +1,28 @@
+/*
+ * File content tracking.
+ *
+ * Copyright (C) 2008 Bahadir Balban
+ */
+#include <fs.h>
+#include <file.h>
+#include <l4/lib/list.h>
+#include <l4/macros.h>
+#include INC_GLUE(memory.h)
+#include <stdio.h>
+
+/* List of all in-memory files. */
+struct list_head vm_file_list;
+
+/*
+ * This reads contents of a file in pages, calling the fs-specific file read function to read-in
+ * those pages' contents.
+ *
+ * Normally this is ought to be called by mm0 when a file's pages cannot be found in the page
+ * cache.
+ */
+int generic_file_read(struct vnode *v, unsigned long pfn, unsigned long npages, void *page_buf)
+{
+	BUG_ON(!is_page_aligned(page_buf));
+
+	return v->fops.read(v, pfn, npages, page_buf);
+}