Implement the typical use of waitpid

kernel/syscall/call.rs

@@ -0,0 +1,57 @@
+use super::{Error, Result};
+
+/// System call list
+/// See http://syscalls.kernelgrok.com/ for numbers
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[repr(C)]
+pub enum Call {
+    /// Exit syscall
+    Exit = 1,
+    /// Read syscall
+    Read = 3,
+    /// Write syscall
+    Write = 4,
+    /// Open syscall
+    Open = 5,
+    /// Close syscall
+    Close = 6,
+    /// Wait for a process
+    WaitPid = 7,
+    /// Execute syscall
+    Exec = 11,
+    /// Get process ID
+    GetPid = 20,
+    /// Duplicate file descriptor
+    Dup = 41,
+    /// Set process break
+    Brk = 45,
+    /// Set process I/O privilege level
+    Iopl = 110,
+    /// Clone process
+    Clone = 120,
+    /// Yield to scheduler
+    SchedYield = 158
+}
+
+/// Convert numbers to calls
+/// See http://syscalls.kernelgrok.com/
+impl Call {
+    pub fn from(number: usize) -> Result<Call> {
+        match number {
+            1 => Ok(Call::Exit),
+            3 => Ok(Call::Read),
+            4 => Ok(Call::Write),
+            5 => Ok(Call::Open),
+            6 => Ok(Call::Close),
+            7 => Ok(Call::WaitPid),
+            11 => Ok(Call::Exec),
+            20 => Ok(Call::GetPid),
+            41 => Ok(Call::Dup),
+            45 => Ok(Call::Brk),
+            110 => Ok(Call::Iopl),
+            120 => Ok(Call::Clone),
+            158 => Ok(Call::SchedYield),
+            _ => Err(Error::NoCall)
+        }
+    }
+}