core: Propagate exit status via notify socket when running in VM

When running in a container, we can propagate the exit status of
pid1 as usual via the process exit status. This is not possible
when running in a VM. Instead, let's send EXIT_STATUS=%i via the
notify socket if one is configured. The user running the VM can then
pick up the exit status from the notify socket after the VM has shut
down.

2 files changed, 10 insertions, 0 deletions

diff --git a/src/core/main.c b/src/core/main.c
index 9588c625b2..e49f6ab094 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -3105,6 +3105,10 @@ finish:
                 error_message = "Failed to execute shutdown binary";
         }
 
+        /* This is primarily useful when running systemd in a VM, as it provides the user running the VM with
+         * a mechanism to pick up systemd's exit status in the VM. */
+        (void) sd_notifyf(0, "EXIT_STATUS=%i", retval);
+
         watchdog_free_device();
         arg_watchdog_device = mfree(arg_watchdog_device);
 
diff --git a/src/shutdown/shutdown.c b/src/shutdown/shutdown.c
index a8248901ce..b1dac20c69 100644
--- a/src/shutdown/shutdown.c
+++ b/src/shutdown/shutdown.c
@@ -14,6 +14,8 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "sd-daemon.h"
+
 #include "alloc-util.h"
 #include "async.h"
 #include "binfmt-util.h"
@@ -570,6 +572,10 @@ int main(int argc, char *argv[]) {
         if (!in_container)
                 sync_with_progress();
 
+        /* This is primarily useful when running systemd in a VM, as it provides the user running the VM with
+         * a mechanism to pick up systemd's exit status in the VM. */
+        (void) sd_notifyf(0, "EXIT_STATUS=%i", arg_exit_code);
+
         if (streq(arg_verb, "exit")) {
                 if (in_container) {
                         log_info("Exiting container.");