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/*
* QEMU yank feature
*
* Copyright (c) Lukas Straub <lukasstraub2@web.de>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/thread.h"
#include "qemu/queue.h"
#include "qemu/lockable.h"
#include "qapi/qapi-commands-yank.h"
#include "qapi/qapi-visit-yank.h"
#include "qapi/clone-visitor.h"
#include "qemu/yank.h"
struct YankFuncAndParam {
YankFn *func;
void *opaque;
QLIST_ENTRY(YankFuncAndParam) next;
};
struct YankInstanceEntry {
YankInstance *instance;
QLIST_HEAD(, YankFuncAndParam) yankfns;
QLIST_ENTRY(YankInstanceEntry) next;
};
typedef struct YankFuncAndParam YankFuncAndParam;
typedef struct YankInstanceEntry YankInstanceEntry;
/*
* This lock protects the yank_instance_list below. Because it's taken by
* OOB-capable commands, it must be "fast", i.e. it may only be held for a
* bounded, short time. See docs/devel/qapi-code-gen.txt for additional
* information.
*/
static QemuMutex yank_lock;
static QLIST_HEAD(, YankInstanceEntry) yank_instance_list
= QLIST_HEAD_INITIALIZER(yank_instance_list);
static bool yank_instance_equal(const YankInstance *a, const YankInstance *b)
{
if (a->type != b->type) {
return false;
}
switch (a->type) {
case YANK_INSTANCE_TYPE_BLOCK_NODE:
return g_str_equal(a->u.block_node.node_name,
b->u.block_node.node_name);
case YANK_INSTANCE_TYPE_CHARDEV:
return g_str_equal(a->u.chardev.id, b->u.chardev.id);
case YANK_INSTANCE_TYPE_MIGRATION:
return true;
default:
abort();
}
}
static YankInstanceEntry *yank_find_entry(const YankInstance *instance)
{
YankInstanceEntry *entry;
QLIST_FOREACH(entry, &yank_instance_list, next) {
if (yank_instance_equal(entry->instance, instance)) {
return entry;
}
}
return NULL;
}
bool yank_register_instance(const YankInstance *instance, Error **errp)
{
YankInstanceEntry *entry;
QEMU_LOCK_GUARD(&yank_lock);
if (yank_find_entry(instance)) {
error_setg(errp, "duplicate yank instance");
return false;
}
entry = g_new0(YankInstanceEntry, 1);
entry->instance = QAPI_CLONE(YankInstance, instance);
QLIST_INIT(&entry->yankfns);
QLIST_INSERT_HEAD(&yank_instance_list, entry, next);
return true;
}
void yank_unregister_instance(const YankInstance *instance)
{
YankInstanceEntry *entry;
QEMU_LOCK_GUARD(&yank_lock);
entry = yank_find_entry(instance);
assert(entry);
assert(QLIST_EMPTY(&entry->yankfns));
QLIST_REMOVE(entry, next);
qapi_free_YankInstance(entry->instance);
g_free(entry);
}
void yank_register_function(const YankInstance *instance,
YankFn *func,
void *opaque)
{
YankInstanceEntry *entry;
YankFuncAndParam *func_entry;
QEMU_LOCK_GUARD(&yank_lock);
entry = yank_find_entry(instance);
assert(entry);
func_entry = g_new0(YankFuncAndParam, 1);
func_entry->func = func;
func_entry->opaque = opaque;
QLIST_INSERT_HEAD(&entry->yankfns, func_entry, next);
}
void yank_unregister_function(const YankInstance *instance,
YankFn *func,
void *opaque)
{
YankInstanceEntry *entry;
YankFuncAndParam *func_entry;
QEMU_LOCK_GUARD(&yank_lock);
entry = yank_find_entry(instance);
assert(entry);
QLIST_FOREACH(func_entry, &entry->yankfns, next) {
if (func_entry->func == func && func_entry->opaque == opaque) {
QLIST_REMOVE(func_entry, next);
g_free(func_entry);
return;
}
}
abort();
}
void qmp_yank(YankInstanceList *instances,
Error **errp)
{
YankInstanceList *tail;
YankInstanceEntry *entry;
YankFuncAndParam *func_entry;
QEMU_LOCK_GUARD(&yank_lock);
for (tail = instances; tail; tail = tail->next) {
entry = yank_find_entry(tail->value);
if (!entry) {
error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, "Instance not found");
return;
}
}
for (tail = instances; tail; tail = tail->next) {
entry = yank_find_entry(tail->value);
assert(entry);
QLIST_FOREACH(func_entry, &entry->yankfns, next) {
func_entry->func(func_entry->opaque);
}
}
}
YankInstanceList *qmp_query_yank(Error **errp)
{
YankInstanceEntry *entry;
YankInstanceList *ret;
ret = NULL;
QEMU_LOCK_GUARD(&yank_lock);
QLIST_FOREACH(entry, &yank_instance_list, next) {
YankInstanceList *new_entry;
new_entry = g_new0(YankInstanceList, 1);
new_entry->value = QAPI_CLONE(YankInstance, entry->instance);
new_entry->next = ret;
ret = new_entry;
}
return ret;
}
static void __attribute__((__constructor__)) yank_init(void)
{
qemu_mutex_init(&yank_lock);
}
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