add syscall: sys_getrandom for python3, etc.

kernel/src/syscall/misc.rs

@@ -201,3 +201,18 @@ pub struct RLimit {
     cur: u64, // soft limit
     max: u64, // hard limit
 }
+
+pub fn sys_getrandom( buf: *mut u8, len: usize, flag: u32)  -> SysResult {
+
+    //info!("getrandom: buf: {:?}, len: {:?}, falg {:?}", buf, len,flag);
+    let mut proc = process();
+    proc.vm.check_write_array(buf, len)?;
+    let slice = unsafe { slice::from_raw_parts_mut(buf, len) };
+    let mut i=0;
+    for elm in slice {
+        unsafe{ *elm=i+ crate::trap::TICK as u8;}
+        i+=1;
+    }
+
+    Ok(len)
+}

kernel/src/syscall/mod.rs

@@ -230,7 +230,9 @@ pub fn syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> isize {
         // custom
         SYS_MAP_PCI_DEVICE => sys_map_pci_device(args[0], args[1]),
         SYS_GET_PADDR => sys_get_paddr(args[0] as *const u64, args[1] as *mut u64, args[2]),
-
+        //SYS_GETRANDOM => unimplemented("getrandom", Err(SysError::EINVAL)),
+        SYS_GETRANDOM =>sys_getrandom( args[0] as *mut u8, args[1] as usize, args[2] as u32),
+        SYS_TKILL => unimplemented("tkill", Ok(0)),
         _ => {
             let ret = match () {
                 #[cfg(target_arch = "x86_64")]