Merge pull request #4 from Richard-Qin-001/dev/shell

Rebuilt the system's underlying structure; it is now stable enough to merge. 

The system now supports a read-only file system and has a simple shell implemented.

1 files changed, 30 insertions, 0 deletions

diff --git a/include/kernel/buf.h b/include/kernel/buf.h
new file mode 100644
index 0000000..099523d
--- /dev/null
+++ b/include/kernel/buf.h
@@ -0,0 +1,30 @@
+#pragma once
+#include "common/types.h"
+#include "kernel/spinlock.h"
+
+#define BSIZE 1024
+#define NBUF 30
+
+struct Buf
+{
+    int valid;        // Whether the data has been read from the disk (1=valid, 0=invalid)
+    int disk;         // Whether it has been held by the driver (dirty bit/write-back flag is usually extended here)
+    uint32 dev;       // Device Number
+    uint32 blockno;   // Block number
+    uint32 refcnt;    // Reference Counting
+    struct Buf *prev; // LRU linked list
+    struct Buf *next;
+    uchar data[BSIZE];
+
+    Mutex lock; // Sleep Lock
+};
+
+namespace BufferCache
+{
+    void init();
+    struct Buf *bread(uint32 dev, uint32 blockno);
+    void bwrite(struct Buf *b);
+    void brelse(struct Buf *b);
+    void bpin(struct Buf *b);
+    void bunpin(struct Buf *b);
+} // namespace BufferCache