[v3,3/5] Mini-OS: don't crash if no shutdown node is available

Commit Message

Jürgen Groß Nov. 21, 2023, 9:49 a.m. UTC

It might be perfectly fine not to have a control/shutdown Xenstore
node. If this is the case, don't crash, but just terminate the
shutdown thread after issuing a message that shutdown isn't available.

In fini_shutdown() clearing the watch can result in an error now, in
case the early exit above was taken. Just ignore this error now.

Signed-off-by: Juergen Gross <[e-mail]>
Reviewed-by: Jason Andryuk <[e-mail]>
---
 shutdown.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

Patch

diff --git a/shutdown.c b/shutdown.c
index bb2c6f11..ded6b64d 100644
--- a/shutdown.c
+++ b/shutdown.c
@@ -75,7 +75,9 @@  static void shutdown_thread(void *p)
         xenbus_wait_for_watch(&events);
         if ((err = xenbus_read(XBT_NIL, path, &shutdown))) {
             free(err);
-            do_exit();
+            free(xenbus_unwatch_path_token(XBT_NIL, path, token));
+            printk("Shutdown Xenstore node not available.\n");
+            return;
         }
 
         if (end_shutdown_thread)
@@ -117,15 +119,9 @@  void init_shutdown(void)
 
 void fini_shutdown(void)
 {
-    char *err;
-
     end_shutdown_thread = 1;
     xenbus_release_wait_for_watch(&events);
-    err = xenbus_unwatch_path_token(XBT_NIL, path, token);
-    if (err) {
-        free(err);
-        do_exit();
-    }
+    free(xenbus_unwatch_path_token(XBT_NIL, path, token));
 }
 #endif