qemu-ga: add a whitelist for fsfreeze-safe commands

Currently we rely on fsfreeze/thaw commands disabling/enabling logging
then having other commands check whether logging is disabled to avoid
executing if they aren't safe for running while a filesystem is frozen.

Instead, have an explicit whitelist of fsfreeze-safe commands, and
consolidate logging and command enablement/disablement into a pair
of helper functions: ga_set_frozen()/ga_unset_frozen()

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

2 files changed, 13 insertions, 2 deletions

diff --git a/qapi/qmp-core.h b/qapi/qmp-core.h
index 3bb3acb..431ddbb 100644
--- a/qapi/qmp-core.h
+++ b/qapi/qmp-core.h
@@ -38,6 +38,7 @@ void qmp_register_command(const char *name, QmpCommandFunc *fn);
 QmpCommand *qmp_find_command(const char *name);
 QObject *qmp_dispatch(QObject *request);
 void qmp_disable_command(const char *name);
+void qmp_enable_command(const char *name);
 bool qmp_command_is_enabled(const char *name);
 char **qmp_get_command_list(void);
 
diff --git a/qapi/qmp-registry.c b/qapi/qmp-registry.c
index 25c89ad..43d5cde 100644
--- a/qapi/qmp-registry.c
+++ b/qapi/qmp-registry.c
@@ -40,18 +40,28 @@ QmpCommand *qmp_find_command(const char *name)
     return NULL;
 }
 
-void qmp_disable_command(const char *name)
+static void qmp_toggle_command(const char *name, bool enabled)
 {
     QmpCommand *cmd;
 
     QTAILQ_FOREACH(cmd, &qmp_commands, node) {
         if (strcmp(cmd->name, name) == 0) {
-            cmd->enabled = false;
+            cmd->enabled = enabled;
             return;
         }
     }
 }
 
+void qmp_disable_command(const char *name)
+{
+    qmp_toggle_command(name, false);
+}
+
+void qmp_enable_command(const char *name)
+{
+    qmp_toggle_command(name, true);
+}
+
 bool qmp_command_is_enabled(const char *name)
 {
     QmpCommand *cmd;