initial implementation of memory mapped files

3 files changed, 76 insertions, 6 deletions

diff --git a/userprog/process.c b/userprog/process.c
index 2771e76..f399038 100644
--- a/userprog/process.c
+++ b/userprog/process.c
@@ -130,6 +130,8 @@ start_process (void *aux)
   thread->process = process;
 
   page_table_init (&thread->page_table);
+  if (!mmap_table_init (&process->mmap_table))
+    goto signal;
 
   /* Initialize interrupt frame and load executable. */
   memset (&if_, 0, sizeof if_);
@@ -149,6 +151,14 @@ start_process (void *aux)
   /* If process startup failed, quit. */
   if (thread->process == NULL)  {
     if (process != NULL) {
+      //TODO: free mmap table + page table?
+
+      /* close/free memory mapped files */
+      //mmap_table_free (&process->mmap_table);
+
+      /* free page table */
+      //page_table_free (&thread->page_table);
+
       if (process->fd_table.fds != NULL)
         palloc_free_page (process->fd_table.fds);
       palloc_free_page (process);
@@ -232,6 +242,9 @@ process_exit (void)
     lock_release (&filesys_lock);
   }
 
+  /* close/free memory mapped files */
+  mmap_table_free (&proc->mmap_table);
+
   int fd;
   for (fd = 2; fd <= proc->fd_table.fd_max; fd++) {
     process_close_file (fd);
@@ -254,6 +267,7 @@ process_exit (void)
     pagedir_destroy (pd);
   }
 
+  /* free page table */
   page_table_free (&thread->page_table);
 
   /* Destroy the process structure if the parent is not alive
@@ -560,8 +574,8 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
       size_t page_zero_bytes = PGSIZE - page_read_bytes;
 
       /* add segment to page table for on demand loading */
-      if (!page_table_insert_segment (file, ofs, upage, page_read_bytes,
-            page_zero_bytes, writable))
+      if (!page_table_insert_segment (&thread_current ()->page_table, file, ofs,
+            upage, page_read_bytes, writable))
         return false;
 
       /* Advance. */
diff --git a/userprog/process.h b/userprog/process.h
index 5fcd80e..bac9a60 100644
--- a/userprog/process.h
+++ b/userprog/process.h
@@ -2,6 +2,7 @@
 #define USERPROG_PROCESS_H
 
 #include "threads/thread.h"
+#include "vm/mmap.h"
 
 #define STACK_SIZE (1 << 23) /* 8MB maximum stack size */
 
@@ -27,6 +28,7 @@ struct process {
     /* files */
     struct file *executable;           /* Loaded executable, if any. */
     struct fd_table fd_table;          /* File descriptor table */
+    struct mmap_table mmap_table;      /* Memory mapped files table */
 
     /* Owned by syscall.c */
     void* syscall_buffer;
diff --git a/userprog/syscall.c b/userprog/syscall.c
index 7f8c397..14cbaab 100644
--- a/userprog/syscall.c
+++ b/userprog/syscall.c
@@ -14,7 +14,8 @@
 #include "userprog/pagedir.h"
 #include "userprog/process.h"
 #include "userprog/syscall.h"
-#include "lib/user/syscall.h"
+#include "vm/mmap.h"
+#include "vm/page.h"
 
 #define STACK_SLOT_SIZE sizeof(int)
 
@@ -226,8 +227,8 @@ syscall_handler (struct intr_frame *f)
     goto fail;
   }
   syscall_sp = sp;
-        result = fp (sp, &segfault);
-        if (segfault)
+  result = fp (sp, &segfault);
+  if (segfault)
     goto fail;
   f->eax = result;
   return;
@@ -574,11 +575,64 @@ syscall_close (void *sp, bool *segfault)
 static int
 syscall_mmap (void *sp, bool *segfault)
 {
-  return 0;
+  int fd;
+  void *addr, *offset;
+  struct file *file, *file2;
+  off_t len;
+
+  /* get arguments */
+  if (! copy_from_user (&fd, STACK_ADDR (sp,1)) ||
+      ! copy_from_user (&addr, STACK_ADDR (sp, 2))) {
+    *segfault = true;
+    return -1;
+  }
+
+  /* address must be valid and page-aligned */
+  if (addr == NULL || pg_ofs (addr))
+    return -1;
+
+  /* file descriptors 0 and 1 are reserved */
+  if (fd == 0 || fd == 1)
+    return -1;
+
+  /* get file */
+  file = process_get_file (fd);
+  if (file == NULL)
+    return -1;
+
+  /* file length must be positiv */
+  len = file_length (file);
+  if (len <= 0)
+    return -1;
+
+  /* check if the pages don't overlap any existing pages */
+  offset = addr;
+  while(offset < addr + len)
+  {
+    if (page_table_fetch (&thread_current ()->page_table, offset))
+      return -1;
+    offset += PGSIZE;
+  }
+
+  process_lock_filesys ();
+  file2 = file_reopen (file);
+  process_unlock_filesys ();
+
+  return (file2 == NULL) ? -1 :
+    mmap_table_insert (&process_current()->mmap_table, addr, file2, len);
 }
 
 static int
 syscall_munmap (void *sp, bool *segfault)
 {
+  mapid_t mapping;
+
+  /* get arguments */
+  if (! copy_from_user (&mapping, STACK_ADDR (sp,1))) {
+    *segfault = true;
+    return 0;
+  }
+
+  mmap_table_remove (&process_current()->mmap_table, mapping);
   return 0;
 }