Orbital (#16)

* Port previous ethernet scheme

* Add ipd

* Fix initfs rebuilds, use QEMU user networking addresses in ipd

* Add tcp/udp, netutils, dns, and network config

* Add fsync to network driver

* Add dns, router, subnet by default

* Fix e1000 driver. Make ethernet and IP non-blocking to avoid deadlocks

* Add orbital server, WIP

* Add futex

* Add orbutils and orbital

* Update libstd, orbutils, and orbital
Move ANSI key encoding to vesad

* Add orbital assets

* Update orbital

* Update to add login manager

* Add blocking primitives, block for most things except waitpid, update orbital

* Wait in waitpid and IRQ, improvements for other waits

* Fevent in root scheme

* WIP: Switch to using fevent

* Reorganize

* Event based e1000d driver

* Superuser-only access to some network schemes, display, and disk

* Superuser root and irq schemes

* Fix orbital

kernel/sync/wait_condition.rs

@@ -0,0 +1,49 @@
+use alloc::arc::Arc;
+use collections::Vec;
+use core::mem;
+use spin::{Mutex, RwLock};
+
+use context::{self, Context};
+
+#[derive(Debug)]
+pub struct WaitCondition {
+    contexts: Mutex<Vec<Arc<RwLock<Context>>>>
+}
+
+impl WaitCondition {
+    pub fn new() -> WaitCondition {
+        WaitCondition {
+            contexts: Mutex::new(Vec::new())
+        }
+    }
+
+    pub fn notify(&self) -> usize {
+        let mut contexts = Vec::new();
+        mem::swap(&mut *self.contexts.lock(), &mut contexts);
+        for context_lock in contexts.iter() {
+            context_lock.write().unblock();
+        }
+        contexts.len()
+    }
+
+    pub fn wait(&self) {
+        {
+            let context_lock = {
+                let contexts = context::contexts();
+                let context_lock = contexts.current().expect("WaitCondition::wait: no context");
+                context_lock.clone()
+            };
+
+            context_lock.write().block();
+
+            self.contexts.lock().push(context_lock);
+        }
+        unsafe { context::switch(); }
+    }
+}
+
+impl Drop for WaitCondition {
+    fn drop(&mut self){
+        self.notify();
+    }
+}