qmp: Dumb down how we run QMP command registration
The way we get QMP commands registered is high tech:
* qapi-commands.py generates qmp_init_marshal() that does the actual work
* it also generates the magic to register it as a MODULE_INIT_QAPI
function, so it runs when someone calls
module_call_init(MODULE_INIT_QAPI)
* main() calls module_call_init()
QEMU needs to register a few non-qapified commands. Same high tech
works: monitor.c has its own qmp_init_marshal() along with the magic
to make it run in module_call_init(MODULE_INIT_QAPI).
QEMU also needs to unregister commands that are not wanted in this
build's configuration (commit 5032a16). Simple enough:
qmp_unregister_commands_hack(). The difficulty is to make it run
after the generated qmp_init_marshal(). We can't simply run it in
monitor.c's qmp_init_marshal(), because the order in which the
registered functions run is indeterminate. So qmp_init_marshal()
registers qmp_unregister_commands_hack() separately. Since
registering *appends* to the list of registered functions, this will
make it run after all the functions that have been registered already.
I suspect it takes a long and expensive computer science education to
not find this silly.
Dumb it down as follows:
* Drop MODULE_INIT_QAPI entirely
* Give the generated qmp_init_marshal() external linkage.
* Call it instead of module_call_init(MODULE_INIT_QAPI)
* Except in QEMU proper, call new monitor_init_qmp_commands() that in
turn calls the generated qmp_init_marshal(), registers the
additional commands and unregisters the unwanted ones.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1488544368-30622-5-git-send-email-armbru@redhat.com>
diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index 09e8467..a75946f 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -208,14 +208,12 @@
def gen_registry(registry):
ret = mcgen('''
-static void qmp_init_marshal(void)
+void qmp_init_marshal(void)
{
''')
ret += registry
ret += mcgen('''
}
-
-qapi_init(qmp_init_marshal);
''')
return ret
@@ -308,6 +306,7 @@
#include "qapi/qmp/qdict.h"
#include "qapi/error.h"
+void qmp_init_marshal(void);
''',
prefix=prefix))