Merge

userprog/syscall.c

@@ -69,9 +69,6 @@ syscall_handler (struct intr_frame *f UNUSED)
   case SYSCALL_CREATE:
     syscall_create(f);
     break;
-  case SYSCALL_REMOVE:
-	syscall_remove(f);
-	break;
   case SYSCALL_WRITE:
     syscall_write(f);
     break;
@@ -83,3 +80,33 @@ syscall_handler (struct intr_frame *f UNUSED)
 	thread_exit();
   }  
 }
+
+static struct list *file_list;
+
+/* Goes through all the files in the file_list and looks for the given file 
+ * Descriptor. Linear search
+ */
+void file_search(struct file_map *f) {
+	// Creates a struct to hold the currently checked file
+	struct file_map *curr_file;
+	// Creates the list element to test for end of list
+	struct list_elem *list_element;
+	*list_element = *list_begin(file_list);
+
+	// Loop to check each file in the linked list in turn
+	while ((curr_file->file_descriptor != f->file_descriptor) &&
+		(is_tail(list_element) == false)
+		) {
+		// Swaps the list_element for the next one in place
+		list_element = list_next(list_element);
+	}
+	// Copies list_element to current file
+	curr_file->list_element = *list_element;
+	// Checks if file has been found returning NULL if not or the file if it has
+	if (curr_file->file_descriptor != f->file_descriptor) {
+		f->file = NULL;
+	}
+	else {
+		f = curr_file;
+	}
+}
\ No newline at end of file

userprog/system_calls.h

@@ -4,6 +4,13 @@
 #include "filesys/file.c" // Added due to dependency for file
 
 // Maps file descriptions to the associated file structure
+struct file_map
+{
+	struct list_elem list_element; // Defined in list.h
+	int file_descriptor;
+	struct file *file; // Defined in file.c
+};
+
 
 /*
  * Terminates Pintos by calling shutdown_power_off()
@@ -11,14 +18,6 @@
  */
 void syscall_halt(struct intr_frame *f);
 
-/*
- * Terminates the current user program, returning status to the kernel. If the
- * process's parent waits for it (see below), this is the status that will be
- * returned. Conventionally, a status of 0 indicates success and nonzero
- * values indicate errors. 
- */
-void syscall_exit(struct intr_frame *f);
-
 /*
  * Runs the executable whose name is given in cmd_line, passing any given
  * arguments, and returns the new process's program id (pid). Must return pid
@@ -35,41 +34,11 @@ void syscall_exec(struct intr_frame *f);
 void syscall_wait(struct intr_frame *f);
 
 /*
- * Creates a new file called file initially initial_size bytes in size.
- * Returns true if successful, false otherwise.
- */
-void syscall_create(struct intr_frame *f);
-
-/*
- * Writes size bytes from buffer to the open file fd.
- * Returns the number of bytes actually written, which may be less than size if
- * some bytes could not be written.
+* Returns the size, in bytes, of the file open as fd.
 */
-void syscall_write(struct intr_frame *f);
+void syscall_filesize(struct intr_frame *f)
 
 /*
- * Opens the file called file. Returns a nonnegative integer handle called a
- * "file descriptor" (fd), or -1 if the file could not be opened.
+ * NOTE: There are more system calls implemented by Pintos but we are not
+ * implementing them because the assignment brief does not ask of it.
  */
\ No newline at end of file
-void syscall_open(struct intr_frame *f);
-
-/*
- * Deletes the file called file. Returns true if successful, false otherwise.
- * A file may be removed regardless of whether it is open or closed, and
- * Removing an open file does not close it. See Removing an Open File, for
- * Details.
- */
-void syscall_remove(struct intr_frame *f);
-
-/*
- * special additional stuff for handling file descriptors because they're annoying
- */
-
-// returns NULL if the given file descriptor does not match a known file
-struct file * get_associated_file_pointer(int fd);
-// remembers the given file, and returns int of file descriptor
-// returns -1 if could not store it (means we've opened too many files)
-int associate_new_file_descriptor(struct file* file_pointer);
-// disassociates the given file descriptor (and its associated pointer)
-// returns false if this failed for some reason
-bool disassociate_file_descriptor(int fd);