Fix close, add dup

kernel/syscall/fs.rs

@@ -11,7 +11,7 @@ pub fn read(fd: usize, buf: &mut [u8]) -> Result<usize> {
         let contexts = context::contexts();
         let context_lock = contexts.current().ok_or(Error::NoProcess)?;
         let context = context_lock.read();
-        let file = context.files.get(fd).ok_or(Error::BadFile)?.ok_or(Error::BadFile)?;
+        let file = context.get_file(fd).ok_or(Error::BadFile)?;
         file
     };
 
@@ -27,7 +27,7 @@ pub fn write(fd: usize, buf: &[u8]) -> Result<usize> {
         let contexts = context::contexts();
         let context_lock = contexts.current().ok_or(Error::NoProcess)?;
         let context = context_lock.read();
-        let file = context.files.get(fd).ok_or(Error::BadFile)?.ok_or(Error::BadFile)?;
+        let file = context.get_file(fd).ok_or(Error::BadFile)?;
         file
     };
 
@@ -65,8 +65,8 @@ pub fn close(fd: usize) -> Result<usize> {
     let file = {
         let contexts = context::contexts();
         let context_lock = contexts.current().ok_or(Error::NoProcess)?;
-        let context = context_lock.read();
-        let file = context.files.get(fd).ok_or(Error::BadFile)?.ok_or(Error::BadFile)?;
+        let mut context = context_lock.write();
+        let file = context.remove_file(fd).ok_or(Error::BadFile)?;
         file
     };
 
@@ -75,3 +75,19 @@ pub fn close(fd: usize) -> Result<usize> {
     let result = scheme_mutex.lock().close(file.number).and(Ok(0));
     result
 }
+
+/// Duplicate file descriptor
+pub fn dup(fd: usize) -> Result<usize> {
+    let file = {
+        let contexts = context::contexts();
+        let context_lock = contexts.current().ok_or(Error::NoProcess)?;
+        let context = context_lock.read();
+        let file = context.get_file(fd).ok_or(Error::BadFile)?;
+        file
+    };
+
+    let schemes = scheme::schemes();
+    let scheme_mutex = schemes.get(file.scheme).ok_or(Error::BadFile)?;
+    let result = scheme_mutex.lock().dup(file.number);
+    result
+}

kernel/syscall/mod.rs

@@ -30,6 +30,8 @@ pub enum Call {
     Exec = 11,
     /// Get process ID
     GetPid = 20,
+    /// Duplicate file descriptor
+    Dup = 41,
     /// Set process break
     Brk = 45,
     /// Set process I/O privilege level
@@ -52,6 +54,7 @@ impl Call {
             6 => Ok(Call::Close),
             11 => Ok(Call::Exec),
             20 => Ok(Call::GetPid),
+            41 => Ok(Call::Dup),
             45 => Ok(Call::Brk),
             110 => Ok(Call::Iopl),
             120 => Ok(Call::Clone),
@@ -112,6 +115,7 @@ pub fn handle(a: usize, b: usize, c: usize, d: usize, e: usize, _f: usize) -> Re
             Call::Close => close(b),
             Call::Exec => exec(convert_slice(b as *const u8, c)?, convert_slice(d as *const [usize; 2], e)?),
             Call::GetPid => getpid(),
+            Call::Dup => dup(b),
             Call::Brk => brk(b),
             Call::Iopl => iopl(b),
             Call::Clone => clone(b),