Changeset 334c103 in mainline for kernel/generic/src/ipc/ops/conctmeto.c

Timestamp:

2018-03-13T18:01:48Z (6 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

87e7a18

Parents:

50dd854

git-author:

Jakub Jermar <jakub@…> (2018-03-10 18:18:12)

git-committer:

Jakub Jermar <jakub@…> (2018-03-13 18:01:48)

Message:

Allow phone_alloc to not publish the capability

This makes it possible and race-free to defer publishing the new
capability until the phone object is connected.

File:

• kernel/generic/src/ipc/ops/conctmeto.c (modified) (1 diff)

kernel/generic/src/ipc/ops/conctmeto.c

@@ -42 +42 @@
 static errno_t request_preprocess(call_t *call, phone_t *phone)
 {
+        /*
+         * Create the new phone and capability, but don't publish them yet.
+         * That will be done once the phone is connected.
+         */
         cap_handle_t phone_handle;
-        errno_t rc = phone_alloc(TASK, &phone_handle);
+        kobject_t *phone_obj;
+        errno_t rc = phone_alloc(TASK, false, &phone_handle, &phone_obj);
         if (rc != EOK) {
                 call->priv = -1;
                 return rc;
-        }
-
-        /*
-         * The capability is now published, but the phone is not connected yet.
-         * The user cannot use it to send anything over it, in fact the
-         * userspace can only unpublish and free the capability at this point.
-         *
-         * We now proceed to test the capability is still there. We don't care
-         * if the user destroyed the old one and recreated a new published one
-         * of the same type under the same handle.
-         *
-         * If the capability is in place we temporarily unpublish it to make
-         * sure the user cannot fiddle with it while we are connecting.
-         */
-
-        kobject_t *phone_obj = cap_unpublish(TASK, phone_handle,
-            KOBJECT_TYPE_PHONE);
-        if (!phone_obj) {
-                /*
-                 * Another thread of the same task can destroy the new
-                 * capability before we manage to get a reference from it.
-                 */
-                call->priv = -1;
-                return ENOENT;
         }