Initialize contexts, add getpid

kernel/syscall/mod.rs

@@ -28,6 +28,8 @@ pub enum Call {
     Close = 6,
     /// Execute syscall
     Exec = 11,
+    /// Get process ID
+    GetPid = 20,
 }
 
 /// Convert numbers to calls
@@ -41,6 +43,7 @@ impl Call {
             5 => Ok(Call::Open),
             6 => Ok(Call::Close),
             11 => Ok(Call::Exec),
+            20 => Ok(Call::GetPid),
             _ => Err(Error::NoCall)
         }
     }
@@ -90,7 +93,8 @@ pub fn handle(a: usize, b: usize, c: usize, d: usize, e: usize, _f: usize) -> Re
         Call::Write => write(b, convert_slice(c as *const u8, d)?),
         Call::Open => open(convert_slice(b as *const u8, c)?, d),
         Call::Close => close(b),
-        Call::Exec => exec(convert_slice(b as *const u8, c)?, convert_slice(d as *const [usize; 2], e)?)
+        Call::Exec => exec(convert_slice(b as *const u8, c)?, convert_slice(d as *const [usize; 2], e)?),
+        Call::GetPid => getpid(),
     }
 }
 

kernel/syscall/process.rs

@@ -2,7 +2,9 @@
 
 use arch::interrupt::halt;
 
-use super::{convert_slice, Result};
+use context;
+
+use super::{convert_slice, Error, Result};
 
 pub fn exit(status: usize) -> ! {
     println!("Exit {}", status);
@@ -19,3 +21,12 @@ pub fn exec(path: &[u8], args: &[[usize; 2]]) -> Result<usize> {
     println!("");
     Ok(0)
 }
+
+pub fn getpid() -> Result<usize> {
+    if let Some(context_lock) = context::contexts().current() {
+        let context = context_lock.read();
+        Ok(context.id)
+    } else {
+        Err(Error::NoProcess)
+    }
+}