Add exit notifiers.

Hook up any cleanup work which needs to be done here.  Advantages over
using atexit(3):

  (1) You get passed in a pointer to the notifier.  If you embed that
      into your state struct you can use container_of() to get get your
      state info.
  (2) You can unregister, say when un-plugging a device.

[ v2: move code out of #ifndef _WIN32 ]

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/sysemu.h b/sysemu.h
index fbe103bc34..c758243ca1 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -6,6 +6,7 @@
 #include "qemu-option.h"
 #include "qemu-queue.h"
 #include "qemu-timer.h"
+#include "notify.h"
 
 #ifdef _WIN32
 #include <windows.h>
@@ -56,6 +57,9 @@ int qemu_powerdown_requested(void);
 extern qemu_irq qemu_system_powerdown;
 void qemu_system_reset(void);
 
+void qemu_add_exit_notifier(Notifier *notify);
+void qemu_remove_exit_notifier(Notifier *notify);
+
 void do_savevm(Monitor *mon, const QDict *qdict);
 int load_vmstate(const char *name);
 void do_delvm(Monitor *mon, const QDict *qdict);
diff --git a/vl.c b/vl.c
index df18198a1e..e5e43b3593 100644
--- a/vl.c
+++ b/vl.c
@@ -234,6 +234,9 @@ uint8_t qemu_uuid[16];
 static QEMUBootSetHandler *boot_set_handler;
 static void *boot_set_opaque;
 
+static NotifierList exit_notifiers =
+    NOTIFIER_LIST_INITIALIZER(exit_notifiers);
+
 int kvm_allowed = 0;
 uint32_t xen_domid;
 enum xen_mode xen_mode = XEN_EMULATE;
@@ -1740,6 +1743,21 @@ static int debugcon_parse(const char *devname)
     return 0;
 }
 
+void qemu_add_exit_notifier(Notifier *notify)
+{
+    notifier_list_add(&exit_notifiers, notify);
+}
+
+void qemu_remove_exit_notifier(Notifier *notify)
+{
+    notifier_list_remove(&exit_notifiers, notify);
+}
+
+static void qemu_run_exit_notifiers(void)
+{
+    notifier_list_notify(&exit_notifiers);
+}
+
 static const QEMUOption *lookup_opt(int argc, char **argv,
                                     const char **poptarg, int *poptind)
 {
@@ -1804,6 +1822,7 @@ int main(int argc, char **argv, char **envp)
     int show_vnc_port = 0;
     int defconfig = 1;
 
+    atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
 
     init_clocks();