Implement page fault for lazy loading executables, w/ G

src/vm/page.c

@@ -1,5 +1,11 @@
 #include "page.h"
+#include <string.h>
+#include <stdio.h>
+#include "filesys/file.h"
 #include "threads/malloc.h"
+#include "threads/palloc.h"
+#include "userprog/process.h"
+#include "vm/frame.h"
 
 /* Hashing function needed for the SPT table. Returns a hash for an entry,
    based on its upage. */
@@ -45,7 +51,7 @@ page_insert (struct file *file, off_t ofs, void *upage, uint32_t read_bytes,
 
 /* Gets a page_entry from the starting address of the page. Returns NULL if no
    such page_entry exists in the hash map.*/
-static struct page_entry *
+struct page_entry *
 page_get (void *upage)
 {
   struct page_entry fake_page_entry;
@@ -60,6 +66,36 @@ page_get (void *upage)
   return hash_entry (e, struct page_entry, elem);
 }
 
+bool
+page_load (struct page_entry *page, bool writable)
+{
+  void *frame = frame_alloc (PAL_USER, page->upage, thread_current());
+  if (frame == NULL)
+    return false; // TODO: Try to evict a page instead.
+
+  if (!install_page (page->upage, frame, writable))
+  {
+    frame_free (frame);
+    return false;
+  }
+
+  printf ("Hi! 3\n");
+
+  file_seek (page->file, page->offset);
+  int read = -1;
+  if ((read = file_read (page->file, frame, page->read_bytes)) != (int) page->read_bytes)
+  {
+    printf ("%p, %p, %d %d\n", page->file, frame, read, page->offset);
+    frame_free (frame);
+    return false;
+  }
+
+  printf ("Hi! 4\n");
+
+  memset (frame + page->read_bytes, 0, page->zero_bytes);
+  return true;
+}
+
 /* Function to clean up a page_entry. Given the elem of that page_entry, frees
    the page_entry itself. */
 void

src/vm/page.h

@@ -29,6 +29,8 @@ bool page_less (const struct hash_elem *a_, const struct hash_elem *b_,
 struct page_entry *page_insert (struct file *file, off_t ofs, void *upage,
                                 uint32_t read_bytes, uint32_t zero_bytes,
                                 bool writable, enum page_type type);
+struct page_entry *page_get (void *upage);
+bool page_load (struct page_entry *page, bool writable);
 void page_cleanup (struct hash_elem *e, void *aux);
 void page_set_swap (struct thread *, void *, size_t);
 size_t page_get_swap (struct thread *, void *);