From d89e2b2a492fa57dce18d446d7107da16dbda324 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@cs.stanford.edu>
Date: Wed, 18 Aug 2004 16:03:26 +0000
Subject: [PATCH] Beginnings of userspace.

---
 src/filesys/build/Makefile |  8 ++--
 src/userprog/addrspace.c   | 95 ++++++++++++++++++++++++++++++++++++++
 src/userprog/addrspace.h   | 21 +++++++++
 3 files changed, 121 insertions(+), 3 deletions(-)
 create mode 100644 src/userprog/addrspace.c
 create mode 100644 src/userprog/addrspace.h

diff --git a/src/filesys/build/Makefile b/src/filesys/build/Makefile
index 2c7ce69..2452d58 100644
--- a/src/filesys/build/Makefile
+++ b/src/filesys/build/Makefile
@@ -1,8 +1,10 @@
 TOP_SRCDIR = ../..
-DEFINES = -DFILESYS -DFILESYS_STUB
-SOURCES = $(THREADS_SRC) $(DEVICES_SRC) $(LIB_SRC) $(FILESYS_SRC)
+DEFINES = -DUSERPROG -DFILESYS
+SOURCES = $(THREADS_SRC) $(DEVICES_SRC) $(LIB_SRC) $(USERPROG_SRC) \
+	  $(FILESYS_SRC)
 INCLUDES = -I$(TOP_SRCDIR)/threads -I$(TOP_SRCDIR)/devices \
-	   -I$(TOP_SRCDIR)/lib -I$(TOP_SRCDIR)/filesys
+	   -I$(TOP_SRCDIR)/lib -I$(TOP_SRCDIR)/userprog \
+	   -I$(TOP_SRCDIR)/filesys
 
 include ../../Makefile.inc
 
diff --git a/src/userprog/addrspace.c b/src/userprog/addrspace.c
new file mode 100644
index 0000000..effd25f
--- /dev/null
+++ b/src/userprog/addrspace.c
@@ -0,0 +1,95 @@
+#include "addrspace.h"
+
+/* We load ELF binaries.  The following definitions are taken
+   from the ELF specification more-or-less literally. */
+
+/* ELF types. */
+typedef uint32_t Elf32_Word, Elf32_Addr, Elf32_Off;
+typedef uint16_t Elf32_Half;
+
+/* Executable header.
+   This appears at the very beginning of an ELF binary. */
+struct Elf32_Ehdr
+  {
+    unsigned char e_ident[16];
+    Elf32_Half    e_type;
+    Elf32_Half    e_machine;
+    Elf32_Word    e_version;
+    Elf32_Addr    e_entry;
+    Elf32_Off     e_phoff;
+    Elf32_Off     e_shoff;
+    Elf32_Word    e_flags;
+    Elf32_Half    e_ehsize;
+    Elf32_Half    e_phentsize;
+    Elf32_Half    e_phnum;
+    Elf32_Half    e_shentsize;
+    Elf32_Half    e_shnum;
+    Elf32_Half    e_shstrndx;
+  };
+
+/* Program header.
+   There are e_phnum of these, starting at file offset e_phoff. */
+struct Elf32_Phdr
+  {
+    Elf32_Word p_type;
+    Elf32_Off  p_offset;
+    Elf32_Addr p_vaddr;
+    Elf32_Addr p_paddr;
+    Elf32_Word p_filesz;
+    Elf32_Word p_memsz;
+    Elf32_Word p_flags;
+    Elf32_Word p_align;
+  };
+
+/* Values for p_type in struct Elf32_Phdr. */
+#define PT_NULL    0    /* Ignore this program header. */
+#define PT_LOAD    1    /* Loadable segment. */
+#define PT_DYNAMIC 2    /* Dynamic linking info. */
+#define PT_INTERP  3    /* Name of dynamic loader. */
+#define PT_NOTE    4    /* Auxiliary info. */
+#define PT_SHLIB   5    /* Reserved. */
+#define PT_PHDR    6    /* Program header table. */
+
+#define LOAD_ERROR(MSG)                                         \
+        do {                                                    \
+                printk ("addrspace_load: %s: ", filename);      \
+                printk MSG;                                     \
+                printk ("\n");                                  \
+                goto error;                                     \
+        } while (0)
+
+bool
+addrspace_load (struct addrspace *as, const char *filename) 
+{
+  Elf32_Ehdr ehdr;
+  struct file *file;
+
+  file = filesys_open (filename);
+  if (file == NULL)
+    LOAD_ERROR (("open failed"));
+
+  /* Read and verify executable header. */
+  if (file_read (file, &ehdr, sizeof ehdr) != sizeof ehdr) 
+    LOAD_ERROR (("error reading executable header"));
+  if (memcmp (ehdr.e_ident, "\x7fELF\1\1\1", 7) != 0)
+    LOAD_ERROR (("not an ELF file"));
+  if (ehdr.e_type != 2)
+    LOAD_ERROR (("not an executable"));
+  if (ehdr.e_machine != 3)
+    LOAD_ERROR (("not an x86 binary"));
+  if (ehdr.e_version != 1)
+    LOAD_ERROR (("unknown ELF version %d", (int) ehdr.e_version));
+  if (ehdr.e_phentsize != sizeof (struct Elf32_Phdr))
+    LOAD_ERROR (("bad program header size", (int) ehdr.e_phentsize));
+  if (ehdr.e_phnum > 1024)
+    LOAD_ERROR (("too many program headers"));
+
+  /* Read program headers. */
+
+  as->page_dir = create_page_dir ();
+  list_init (&as->vmas);
+
+  
+  
+
+}
diff --git a/src/userprog/addrspace.h b/src/userprog/addrspace.h
new file mode 100644
index 0000000..b6f2cc3
--- /dev/null
+++ b/src/userprog/addrspace.h
@@ -0,0 +1,21 @@
+#ifndef HEADER_ADDRSPACE_H
+#define HEADER_ADDRSPACE_H 1
+
+#include "list.h"
+
+struct vma 
+  {
+    struct list_elem elem;
+    uint32_t start, end;
+    void **pages;
+  };
+
+struct addrspace 
+  {
+    uint32_t *page_dir;
+    struct list vmas;
+  };
+
+void addrspace_load (struct addrspace *, const char *);
+
+#endif /* addrspace.h */
-- 
2.30.2