Changeset 8498915 in mainline for uspace

Timestamp:

2007-11-22T09:09:04Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

0cc4313

Parents:

b74959bd

Message:

Be more deterministic when a user accidently uses fast version of IPC
call/answer instead of the full one and passes fewer arguments than required by
the recipient of the call/response.

and the recipient interprets arguments that
were actually not passed by the sender.

File:

• uspace/lib/libc/generic/ipc.c (modified) (3 diffs)

uspace/lib/libc/generic/ipc.c

@@ -321 +321 @@
                 IPC_SET_ARG3(call->u.msg.data, arg3);
                 IPC_SET_ARG4(call->u.msg.data, arg4);
+                /*
+                 * To achieve deterministic behavior, we always zero out the
+                 * arguments that are beyond the limits of the fast version.
+                 */
+                IPC_SET_ARG5(call->u.msg.data, 0);
         }
         ipc_finish_async(callid, phoneid, call, can_preempt);
@@ -436 +441 @@
         while (!list_empty(&queued_calls)) {
                 call = list_get_instance(queued_calls.next, async_call_t, list);
-                callid = _ipc_call_async(call->u.msg.phoneid, &call->u.msg.data);
+                callid = _ipc_call_async(call->u.msg.phoneid,
+                    &call->u.msg.data);
                 if (callid == IPC_CALLRET_TEMPORARY) {
                         break;
@@ -646 +652 @@
  * For non-system methods, the old method and arg1 are rewritten by the new
  * values. For system methods, the new method and arg1 are written to the old
- * arg1 and arg2, respectivelly.
- */
-int ipc_forward_fast(ipc_callid_t callid, int phoneid, int method, ipcarg_t arg1)
+ * arg1 and arg2, respectivelly. Calls with immutable methods are forwarded
+ * verbatim.
+ */
+int ipc_forward_fast(ipc_callid_t callid, int phoneid, int method,
+    ipcarg_t arg1)
 {
         return __SYSCALL4(SYS_IPC_FORWARD_FAST, callid, phoneid, method, arg1);