WIP: User scheme

kernel/syscall/call.rs

@@ -1,5 +1,3 @@
-use super::{Error, Result};
-
 /// System call list
 /// See http://syscalls.kernelgrok.com/ for numbers
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -42,26 +40,25 @@ pub enum Call {
 /// Convert numbers to calls
 /// See http://syscalls.kernelgrok.com/
 impl Call {
-    //TODO: Return Option<Call>
-    pub fn from(number: usize) -> Result<Call> {
+    pub fn from(number: usize) -> Option<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),
-            12 => Ok(Call::ChDir),
-            20 => Ok(Call::GetPid),
-            41 => Ok(Call::Dup),
-            45 => Ok(Call::Brk),
-            110 => Ok(Call::Iopl),
-            118 => Ok(Call::FSync),
-            120 => Ok(Call::Clone),
-            158 => Ok(Call::SchedYield),
-            183 => Ok(Call::GetCwd),
-            _ => Err(Error::NoCall)
+            1 => Some(Call::Exit),
+            3 => Some(Call::Read),
+            4 => Some(Call::Write),
+            5 => Some(Call::Open),
+            6 => Some(Call::Close),
+            7 => Some(Call::WaitPid),
+            11 => Some(Call::Exec),
+            12 => Some(Call::ChDir),
+            20 => Some(Call::GetPid),
+            41 => Some(Call::Dup),
+            45 => Some(Call::Brk),
+            110 => Some(Call::Iopl),
+            118 => Some(Call::FSync),
+            120 => Some(Call::Clone),
+            158 => Some(Call::SchedYield),
+            183 => Some(Call::GetCwd),
+            _ => None
         }
     }
 }

kernel/syscall/error.rs

@@ -31,4 +31,33 @@ pub enum Error {
     NoCall = 38
 }
 
+impl Error {
+    pub fn from(number: usize) -> Option<Error> {
+        match number {
+            1 => Some(Error::NotPermitted),
+            2 => Some(Error::NoEntry),
+            3 => Some(Error::NoProcess),
+            8 => Some(Error::NoExec),
+            9 => Some(Error::BadFile),
+            11 => Some(Error::TryAgain),
+            14 => Some(Error::Fault),
+            17 => Some(Error::FileExists),
+            19 => Some(Error::NoDevice),
+            22 => Some(Error::InvalidValue),
+            24 => Some(Error::TooManyFiles),
+            29 => Some(Error::IllegalSeek),
+            38 => Some(Error::NoCall),
+            _ => None
+        }
+    }
+}
+
 pub type Result<T> = ::core::result::Result<T, Error>;
+
+pub fn convert_to_result(number: usize) -> Result<usize> {
+    if let Some(err) = Error::from((-(number as isize)) as usize) {
+        Err(err)
+    } else {
+        Ok(number)
+    }
+}

kernel/syscall/mod.rs

@@ -26,7 +26,7 @@ pub extern fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize
     #[inline(always)]
     fn inner(a: usize, b: usize, c: usize, d: usize, e: usize, _f: usize, stack: usize) -> Result<usize> {
         match Call::from(a) {
-            Ok(call) => match call {
+            Some(call) => match call {
                 Call::Exit => exit(b),
                 Call::Read => read(b, validate_slice_mut(c as *mut u8, d)?),
                 Call::Write => write(b, validate_slice(c as *const u8, d)?),
@@ -44,9 +44,9 @@ pub extern fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize
                 Call::SchedYield => sched_yield(),
                 Call::GetCwd => getcwd(validate_slice_mut(b as *mut u8, c)?)
             },
-            Err(err) => {
+            None => {
                 println!("Unknown syscall {}", a);
-                Err(err)
+                Err(Error::NoCall)
             }
         }
     }