lab 2 (probably working)

kern/syscall/file_syscalls.c

@@ -0,0 +1,32 @@
+#include <syscall.h>
+#include <lib.h>
+#include <kern/unistd.h>
+
+size_t sys_read(int fh, userptr_t buf, size_t size) {
+  int i=0;
+  int * ary = (int*)buf;
+  if (fh!=STDIN_FILENO) {
+    kprintf("sys_read supported only to stdin\n");
+    return -1;
+  }
+
+  for (i=0;i<(int)size;i++) {
+    ary[i] = getch();
+  }
+  return i;
+}
+
+size_t sys_write(int fh, const userptr_t buf, size_t size) {
+  int i=0;
+  int * ary = (int*)buf;
+  
+  if (fh!=STDOUT_FILENO && fh!=STDERR_FILENO) {
+    kprintf("sys_write supported only to stdout\n");
+    return -1;
+  }
+
+  for (i=0;i<(int)size;i++) {
+    putch(ary[i]);
+  }
+  return i;
+}

kern/syscall/proc_syscalls.c

@@ -0,0 +1,15 @@
+#include <syscall.h>
+#include <proc.h>
+#include <thread.h>
+#include <addrspace.h>
+
+void sys__exit(int status) {
+  (void)status;
+  /* delete current process as */
+  struct addrspace *as = proc_getas();
+  as_destroy(as);
+  /* exit thread */
+  thread_exit();
+
+  panic("sys__exit end reached!!\n");
+}