Add an offset argument to device read and write functions

e89a9667 · Silas Boyd-Wickizer · 2022c007 · e89a9667 · e89a9667 · e89a9667
--- a/console.c
+++ b/console.c
@@ -170,7 +170,7 @@ panic(const char *s)
 }
 static int
-consolewrite(struct inode *ip, char *buf, int n)
+consolewrite(struct inode *ip, char *buf, u32 off, u32 n)
 {
  int i;
@@ -252,7 +252,7 @@ consoleintr(int (*getc)(void))
 }
 static int
-consoleread(struct inode *ip, char *dst, int n)
+consoleread(struct inode *ip, char *dst, u32 off, u32 n)
 {
  int target;
  int c;

--- a/file.h
+++ b/file.h
@@ -42,10 +42,11 @@ struct inode {
 // device implementations
 struct devsw {
-  int (*read)(struct inode*, char*, int);
+  int (*read)(struct inode*, char*, u32, u32);
-  int (*write)(struct inode*, char*, int);
+  int (*write)(struct inode*, char*, u32, u32);
 };
 extern struct devsw devsw[];
 #define CONSOLE 1
+#define NETIF   2
--- a/fs.c
+++ b/fs.c
@@ -516,7 +516,7 @@ readi(struct inode *ip, char *dst, u32 off, u32 n)
  if(ip->type == T_DEV){
    if(ip->major < 0 || ip->major >= NDEV || !devsw[ip->major].read)
      return -1;
-    return devsw[ip->major].read(ip, dst, n);
+    return devsw[ip->major].read(ip, dst, off, n);
  }
  if(off > ip->size || off + n < off)
@@ -544,7 +544,7 @@ writei(struct inode *ip, char *src, u32 off, u32 n)
  if(ip->type == T_DEV){
    if(ip->major < 0 || ip->major >= NDEV || !devsw[ip->major].write)
      return -1;
-    return devsw[ip->major].write(ip, src, n);
+    return devsw[ip->major].write(ip, src, off, n);
  }
  if(off > ip->size || off + n < off)