1 files changed, 76 insertions, 0 deletions
diff --git a/src/rc-local-generator/rc-local-generator.c b/src/rc-local-generator/rc-local-generator.c
new file mode 100644
index 0000000..89cc5fa
--- /dev/null
+++ b/src/rc-local-generator/rc-local-generator.c
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "generator.h"
+#include "initrd-util.h"
+#include "log.h"
+#include "mkdir-label.h"
+#include "string-util.h"
+
+static const char *arg_dest = NULL;
+
+/* So you are reading this, and might wonder: why is this implemented as a generator rather than as a plain, statically
+ * enabled service that carries appropriate ConditionFileIsExecutable= lines? The answer is this: conditions bypass
+ * execution of a service's binary, but they have no influence on unit dependencies. Thus, a service that is
+ * conditioned out will still act as synchronization point in the dependency tree, and we'd rather not have that for
+ * these two legacy scripts. */
+
+static int add_symlink(const char *service, const char *where) {
+        const char *from, *to;
+
+        assert(service);
+        assert(where);
+
+        from = strjoina(SYSTEM_DATA_UNIT_DIR "/", service);
+        to = strjoina(arg_dest, "/", where, ".wants/", service);
+
+        (void) mkdir_parents_label(to, 0755);
+
+        if (symlink(from, to) < 0) {
+                if (errno == EEXIST)
+                        return 0;
+
+                return log_error_errno(errno, "Failed to create symlink %s: %m", to);
+        }
+
+        return 1;
+}
+
+static int check_executable(const char *path) {
+        assert(path);
+
+        if (access(path, X_OK) < 0) {
+                if (errno == ENOENT)
+                        return log_debug_errno(errno, "%s does not exist, skipping.", path);
+                if (errno == EACCES)
+                        return log_info_errno(errno, "%s is not marked executable, skipping.", path);
+
+                return log_warning_errno(errno, "Couldn't determine if %s exists and is executable, skipping: %m", path);
+        }
+
+        return 0;
+}
+
+static int run(const char *dest, const char *dest_early, const char *dest_late) {
+        int r = 0, k = 0;
+
+        assert_se(arg_dest = dest);
+
+        if (in_initrd()) {
+                log_debug("Skipping generator, running in the initrd.");
+                return EXIT_SUCCESS;
+        }
+
+        if (check_executable(RC_LOCAL_PATH) >= 0) {
+                log_debug("Automatically adding rc-local.service.");
+
+                r = add_symlink("rc-local.service", "multi-user.target");
+        }
+
+        return r < 0 ? r : k;
+}
+
+DEFINE_MAIN_GENERATOR_FUNCTION(run);