[Qemu-devel] [PATCH 1/1] vl.c: call optional script when exiting

[Dominik Csapak <d.csapak@proxmox.com>]

some users might want to call a script when qemu exits, without listening
to a qmp monitor for events when running with --daemonize

this can be used for things like external cleanups

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 qemu-options.hx | 18 ++++++++++++++++++
 vl.c            | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index f139459e80..03dcccee7f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3421,6 +3421,24 @@ This allows for instance switching to monitor to commit changes to the
 disk image.
 ETEXI
 
+DEF("exit-script", HAS_ARG, QEMU_OPTION_exit_script, \
+    "-exit-script    <file>\n"
+    "                      Execute the script in file on exit.\n"
+    "                      The arguments are:\n"
+    "                       - the shutdown reason,\n"
+    "                       - if it was really a reset (if -no-reboot was set)\n"
+    "                       - the name of the guest",
+    QEMU_ARCH_ALL)
+STEXI
+@item -exit-script @var{file}
+@findex -exit-script
+Execute the script $var{file} on exit.
+The arguments are:
+ - the shutdown reason
+ - if it was really a reset (if -no-reboot was set)
+ - the name of the guest
+ETEXI
+
 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
     "-loadvm [tag|id]\n" \
     "                start right away with a saved state (loadvm in monitor)\n",
diff --git a/vl.c b/vl.c
index cc55fe04a2..818381cd76 100644
--- a/vl.c
+++ b/vl.c
@@ -1522,6 +1522,9 @@ void vm_state_notify(int running, RunState state)
     }
 }
 
+static ShutdownCause shutdown_reason;
+static bool shutdown_was_reset;
+
 static ShutdownCause reset_requested;
 static ShutdownCause shutdown_requested;
 static int shutdown_signal;
@@ -1681,6 +1684,7 @@ void qemu_system_guest_panicked(GuestPanicInformation *info)
 void qemu_system_reset_request(ShutdownCause reason)
 {
     if (no_reboot && reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) {
+        shutdown_was_reset = true;
         shutdown_requested = reason;
     } else {
         reset_requested = reason;
@@ -1811,6 +1815,7 @@ static bool main_loop_should_exit(void)
         if (no_shutdown) {
             vm_stop(RUN_STATE_SHUTDOWN);
         } else {
+            shutdown_reason = request;
             return true;
         }
     }
@@ -2899,6 +2904,7 @@ int main(int argc, char **argv, char **envp)
     Error *err = NULL;
     bool list_data_dirs = false;
     char *dir, **dirs;
+    const char *exit_script = NULL;
     typedef struct BlockdevOptions_queue {
         BlockdevOptions *bdo;
         Location loc;
@@ -3587,6 +3593,9 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_no_shutdown:
                 no_shutdown = 1;
                 break;
+            case QEMU_OPTION_exit_script:
+                exit_script = optarg;
+                break;
             case QEMU_OPTION_show_cursor:
                 cursor_hide = 0;
                 break;
@@ -4577,5 +4586,41 @@ int main(int argc, char **argv, char **envp)
     migration_object_finalize();
     /* TODO: unref root container, check all devices are ok */
 
+    if (exit_script) {
+        int pid, status;
+        char *args[5];
+
+        /* try to launch network script */
+        pid = fork();
+        if (pid < 0) {
+            error_report("could not launch exit script '%s'", exit_script);
+            exit(1);
+        }
+        if (pid == 0) {
+            int open_max = sysconf(_SC_OPEN_MAX), i;
+
+            for (i = 3; i < open_max; i++) {
+                close(i);
+            }
+            args[0] = (char *)exit_script;
+            args[1] = g_strdup_printf("%d", shutdown_reason);
+            args[2] = g_strdup_printf("%d", shutdown_was_reset);
+            args[3] = qemu_get_vm_name();
+            args[4] = NULL;
+            execv(exit_script, args);
+            _exit(1);
+        } else {
+            while (waitpid(pid, &status, 0) != pid) {
+                /* loop */
+            }
+
+            if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+                error_report("exit script '%s' failed with status %d",
+                             exit_script, status);
+                exit(1);
+            }
+        }
+    }
+
     return 0;
 }
-- 
2.11.0