vl: add qemu_add_vm_change_state_handler_prio()

Add an API for registering vm change state handlers with a well-defined
ordering.  This is necessary when handlers depend on each other.

Small coding style fixes are included to make checkpatch.pl happy.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2019-06-20 18:37:07 +01:00 committed by Kevin Wolf
parent df34fe314b
commit 60dbc5a1c5
2 changed files with 52 additions and 15 deletions

View file

@ -29,6 +29,8 @@ typedef void VMChangeStateHandler(void *opaque, int running, RunState state);
VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,
void *opaque);
VMChangeStateEntry *qemu_add_vm_change_state_handler_prio(
VMChangeStateHandler *cb, void *opaque, int priority);
void qemu_del_vm_change_state_handler(VMChangeStateEntry *e);
void vm_state_notify(int running, RunState state);

65
vl.c
View file

@ -1365,28 +1365,57 @@ static int machine_help_func(QemuOpts *opts, MachineState *machine)
struct vm_change_state_entry {
VMChangeStateHandler *cb;
void *opaque;
QLIST_ENTRY (vm_change_state_entry) entries;
QTAILQ_ENTRY(vm_change_state_entry) entries;
int priority;
};
static QLIST_HEAD(, vm_change_state_entry) vm_change_state_head;
static QTAILQ_HEAD(, vm_change_state_entry) vm_change_state_head;
/**
* qemu_add_vm_change_state_handler_prio:
* @cb: the callback to invoke
* @opaque: user data passed to the callback
* @priority: low priorities execute first when the vm runs and the reverse is
* true when the vm stops
*
* Register a callback function that is invoked when the vm starts or stops
* running.
*
* Returns: an entry to be freed using qemu_del_vm_change_state_handler()
*/
VMChangeStateEntry *qemu_add_vm_change_state_handler_prio(
VMChangeStateHandler *cb, void *opaque, int priority)
{
VMChangeStateEntry *e;
VMChangeStateEntry *other;
e = g_malloc0(sizeof(*e));
e->cb = cb;
e->opaque = opaque;
e->priority = priority;
/* Keep list sorted in ascending priority order */
QTAILQ_FOREACH(other, &vm_change_state_head, entries) {
if (priority < other->priority) {
QTAILQ_INSERT_BEFORE(other, e, entries);
return e;
}
}
QTAILQ_INSERT_TAIL(&vm_change_state_head, e, entries);
return e;
}
VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,
void *opaque)
{
VMChangeStateEntry *e;
e = g_malloc0(sizeof (*e));
e->cb = cb;
e->opaque = opaque;
QLIST_INSERT_HEAD(&vm_change_state_head, e, entries);
return e;
return qemu_add_vm_change_state_handler_prio(cb, opaque, 0);
}
void qemu_del_vm_change_state_handler(VMChangeStateEntry *e)
{
QLIST_REMOVE (e, entries);
g_free (e);
QTAILQ_REMOVE(&vm_change_state_head, e, entries);
g_free(e);
}
void vm_state_notify(int running, RunState state)
@ -1395,8 +1424,14 @@ void vm_state_notify(int running, RunState state)
trace_vm_state_notify(running, state, RunState_str(state));
QLIST_FOREACH_SAFE(e, &vm_change_state_head, entries, next) {
e->cb(e->opaque, running, state);
if (running) {
QTAILQ_FOREACH_SAFE(e, &vm_change_state_head, entries, next) {
e->cb(e->opaque, running, state);
}
} else {
QTAILQ_FOREACH_REVERSE_SAFE(e, &vm_change_state_head, entries, next) {
e->cb(e->opaque, running, state);
}
}
}
@ -2911,7 +2946,7 @@ int main(int argc, char **argv, char **envp)
exit(1);
}
QLIST_INIT (&vm_change_state_head);
QTAILQ_INIT(&vm_change_state_head);
os_setup_early_signal_handling();
cpu_option = NULL;