[PATCH V3 4/9] vl: helper to request exec

[Steve Sistare <steven.sistare@oracle.com>]

Add a qemu_system_exec_request() hook that causes the main loop to exit and
exec a command using the specified arguments.  This will be used during CPR
to exec a new version of QEMU.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 include/system/runstate.h |  3 +++
 system/runstate.c         | 29 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/system/runstate.h b/include/system/runstate.h
index 929379a..c005f49 100644
--- a/include/system/runstate.h
+++ b/include/system/runstate.h
@@ -128,6 +128,8 @@ typedef enum WakeupReason {
     QEMU_WAKEUP_REASON_OTHER,
 } WakeupReason;
 
+typedef void (*qemu_exec_func)(char **exec_argv);
+
 void qemu_system_reset_request(ShutdownCause reason);
 void qemu_system_suspend_request(void);
 void qemu_register_suspend_notifier(Notifier *notifier);
@@ -139,6 +141,7 @@ void qemu_register_wakeup_support(void);
 void qemu_system_shutdown_request_with_code(ShutdownCause reason,
                                             int exit_code);
 void qemu_system_shutdown_request(ShutdownCause reason);
+void qemu_system_exec_request(qemu_exec_func func, const strList *args);
 void qemu_system_powerdown_request(void);
 void qemu_register_powerdown_notifier(Notifier *notifier);
 void qemu_register_shutdown_notifier(Notifier *notifier);
diff --git a/system/runstate.c b/system/runstate.c
index 6178b00..b4980ff 100644
--- a/system/runstate.c
+++ b/system/runstate.c
@@ -41,6 +41,7 @@
 #include "qapi/error.h"
 #include "qapi/qapi-commands-run-state.h"
 #include "qapi/qapi-events-run-state.h"
+#include "qapi/type-helpers.h"
 #include "qemu/accel.h"
 #include "qemu/error-report.h"
 #include "qemu/job.h"
@@ -422,6 +423,8 @@ static NotifierList wakeup_notifiers =
 static NotifierList shutdown_notifiers =
     NOTIFIER_LIST_INITIALIZER(shutdown_notifiers);
 static uint32_t wakeup_reason_mask = ~(1 << QEMU_WAKEUP_REASON_NONE);
+qemu_exec_func exec_func;
+static char **exec_argv;
 
 ShutdownCause qemu_shutdown_requested_get(void)
 {
@@ -443,6 +446,11 @@ static int qemu_shutdown_requested(void)
     return qatomic_xchg(&shutdown_requested, SHUTDOWN_CAUSE_NONE);
 }
 
+static int qemu_exec_requested(void)
+{
+    return exec_argv != NULL;
+}
+
 static void qemu_kill_report(void)
 {
     if (!qtest_driver() && shutdown_signal) {
@@ -803,6 +811,23 @@ void qemu_system_shutdown_request(ShutdownCause reason)
     qemu_notify_event();
 }
 
+static void qemu_system_exec(void)
+{
+    exec_func(exec_argv);
+
+    /* exec failed */
+    g_strfreev(exec_argv);
+    exec_argv = NULL;
+    exec_func = NULL;
+}
+
+void qemu_system_exec_request(qemu_exec_func func, const strList *args)
+{
+    exec_func = func;
+    exec_argv = strv_from_str_list(args);
+    qemu_notify_event();
+}
+
 static void qemu_system_powerdown(void)
 {
     qapi_event_send_powerdown();
@@ -849,6 +874,10 @@ static bool main_loop_should_exit(int *status)
     if (qemu_suspend_requested()) {
         qemu_system_suspend();
     }
+    if (qemu_exec_requested()) {
+        qemu_system_exec();
+        return false;
+    }
     request = qemu_shutdown_requested();
     if (request) {
         qemu_kill_report();
-- 
1.8.3.1