first commit

kernel/file.h

@@ -0,0 +1,40 @@
+struct file {
+  enum { FD_NONE, FD_PIPE, FD_INODE, FD_DEVICE } type;
+  int ref; // reference count
+  char readable;
+  char writable;
+  struct pipe *pipe; // FD_PIPE
+  struct inode *ip;  // FD_INODE and FD_DEVICE
+  uint off;          // FD_INODE
+  short major;       // FD_DEVICE
+};
+
+#define major(dev)  ((dev) >> 16 & 0xFFFF)
+#define minor(dev)  ((dev) & 0xFFFF)
+#define	mkdev(m,n)  ((uint)((m)<<16| (n)))
+
+// in-memory copy of an inode
+struct inode {
+  uint dev;           // Device number
+  uint inum;          // Inode number
+  int ref;            // Reference count
+  struct sleeplock lock; // protects everything below here
+  int valid;          // inode has been read from disk?
+
+  short type;         // copy of disk inode
+  short major;
+  short minor;
+  short nlink;
+  uint size;
+  uint addrs[NDIRECT+1];
+};
+
+// map major device number to device functions.
+struct devsw {
+  int (*read)(int, uint64, int);
+  int (*write)(int, uint64, int);
+};
+
+extern struct devsw devsw[];
+
+#define CONSOLE 1