Allow initfs to be written

kernel/scheme/initfs.rs

-use collections::BTreeMap;
+use alloc::arc::Arc;
+use collections::{BTreeMap, Vec};
 use core::{cmp, str};
 use core::sync::atomic::{AtomicUsize, Ordering};
 use spin::RwLock;
@@ -20,22 +21,27 @@ mod gen;
 
 struct Handle {
     path: &'static [u8],
-    data: &'static [u8],
+    data: Arc<RwLock<Vec<u8>>>,
     mode: u16,
     seek: usize
 }
 
 pub struct InitFsScheme {
     next_id: AtomicUsize,
-    files: BTreeMap<&'static [u8], (&'static [u8], bool)>,
+    files: BTreeMap<&'static [u8], (Arc<RwLock<Vec<u8>>>, bool)>,
     handles: RwLock<BTreeMap<usize, Handle>>
 }
 
 impl InitFsScheme {
     pub fn new() -> InitFsScheme {
+        let mut files = BTreeMap::new();
+        for (path, (data, folder)) in gen::gen() {
+            files.insert(path, (Arc::new(RwLock::new(data.to_vec())), folder));
+        }
+
         InitFsScheme {
             next_id: AtomicUsize::new(0),
-            files: gen::gen(),
+            files: files,
             handles: RwLock::new(BTreeMap::new())
         }
     }
@@ -52,7 +58,7 @@ impl Scheme for InitFsScheme {
                 let id = self.next_id.fetch_add(1, Ordering::SeqCst);
                 self.handles.write().insert(id, Handle {
                     path: entry.0,
-                    data: (entry.1).0,
+                    data: (entry.1).0.clone(),
                     mode: if (entry.1).1 { MODE_DIR |  0o755 } else { MODE_FILE | 0o744 },
                     seek: 0
                 });
@@ -68,7 +74,7 @@ impl Scheme for InitFsScheme {
         let (path, data, mode, seek) = {
             let handles = self.handles.read();
             let handle = handles.get(&id).ok_or(Error::new(EBADF))?;
-            (handle.path, handle.data, handle.mode, handle.seek)
+            (handle.path, handle.data.clone(), handle.mode, handle.seek)
         };
 
         let id = self.next_id.fetch_add(1, Ordering::SeqCst);
@@ -85,10 +91,26 @@ impl Scheme for InitFsScheme {
     fn read(&self, id: usize, buffer: &mut [u8]) -> Result<usize> {
         let mut handles = self.handles.write();
         let mut handle = handles.get_mut(&id).ok_or(Error::new(EBADF))?;
+        let data = handle.data.read();
 
         let mut i = 0;
-        while i < buffer.len() && handle.seek < handle.data.len() {
-            buffer[i] = handle.data[handle.seek];
+        while i < buffer.len() && handle.seek < data.len() {
+            buffer[i] = data[handle.seek];
+            i += 1;
+            handle.seek += 1;
+        }
+
+        Ok(i)
+    }
+
+    fn write(&self, id: usize, buffer: &[u8]) -> Result<usize> {
+        let mut handles = self.handles.write();
+        let mut handle = handles.get_mut(&id).ok_or(Error::new(EBADF))?;
+        let mut data = handle.data.write();
+
+        let mut i = 0;
+        while i < buffer.len() && handle.seek < data.len() {
+            data[handle.seek] = buffer[i];
             i += 1;
             handle.seek += 1;
         }
@@ -99,11 +121,12 @@ impl Scheme for InitFsScheme {
     fn seek(&self, id: usize, pos: usize, whence: usize) -> Result<usize> {
         let mut handles = self.handles.write();
         let mut handle = handles.get_mut(&id).ok_or(Error::new(EBADF))?;
+        let data = handle.data.read();
 
         handle.seek = match whence {
-            SEEK_SET => cmp::min(handle.data.len(), pos),
-            SEEK_CUR => cmp::max(0, cmp::min(handle.data.len() as isize, handle.seek as isize + pos as isize)) as usize,
-            SEEK_END => cmp::max(0, cmp::min(handle.data.len() as isize, handle.data.len() as isize + pos as isize)) as usize,
+            SEEK_SET => cmp::min(data.len(), pos),
+            SEEK_CUR => cmp::max(0, cmp::min(data.len() as isize, handle.seek as isize + pos as isize)) as usize,
+            SEEK_END => cmp::max(0, cmp::min(data.len() as isize, data.len() as isize + pos as isize)) as usize,
             _ => return Err(Error::new(EINVAL))
         };
 
@@ -135,16 +158,20 @@ impl Scheme for InitFsScheme {
     fn fstat(&self, id: usize, stat: &mut Stat) -> Result<usize> {
         let handles = self.handles.read();
         let handle = handles.get(&id).ok_or(Error::new(EBADF))?;
+        let data = handle.data.read();
 
         stat.st_mode = handle.mode;
         stat.st_uid = 0;
         stat.st_gid = 0;
-        stat.st_size = handle.data.len() as u64;
+        stat.st_size = data.len() as u64;
 
         Ok(0)
     }
 
-    fn fsync(&self, _id: usize) -> Result<usize> {
+    fn fsync(&self, id: usize) -> Result<usize> {
+        let handles = self.handles.read();
+        let _handle = handles.get(&id).ok_or(Error::new(EBADF))?;
+
         Ok(0)
     }