core: if we cannot JOB_ISOLATE the default target JOB_REPLACE it instead

In order to maintain compatibility with older initrds which do not have
AllowIsolate=yes set for their target units, fallback to JOB_REPLACE if
JOB_ISOLATE doesn't work, but complain about it.

diff --git a/src/core/main.c b/src/core/main.c
index 727a41074071a5030d1cbe63dad5cb8d9f34d222..7b039835a8cffe03f38164150c1c9b645a6ddfad 100644 (file)
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -1736,11 +1736,22 @@ int main(int argc, char *argv[]) {
                 }
 
                 r = manager_add_job(m, JOB_START, target, JOB_ISOLATE, false, &error, &default_unit_job);
-                if (r < 0) {
-                        log_error("Failed to start default target: %s", bus_error(&error, r));
+                if (r == -EPERM) {
+                        log_error("Default target could not be isolated, starting instead: %s", bus_error(&error, r));
+                        dbus_error_free(&error);
+
+                        r = manager_add_job(m, JOB_START, target, JOB_REPLACE, false, &error, &default_unit_job);
+                        if (r < 0) {
+                                log_error("Failed to start default target: %s", bus_error(&error, r));
+                                dbus_error_free(&error);
+                                goto finish;
+                        }
+                } else if (r < 0) {
+                        log_error("Failed to isolate default target: %s", bus_error(&error, r));
                         dbus_error_free(&error);
                         goto finish;
                 }
+
                 m->default_unit_job_id = default_unit_job->id;
 
                 after_startup = now(CLOCK_MONOTONIC);