basic: split out update_reboot_parameter_and_warn() into its own .c/.h files

This is primarily preparation for a follow-up commit that adds a common
implementation of the other side of the reboot parameter file, i.e. the
code that reads the file and issues reboot() for it.

1 files changed, 34 insertions, 0 deletions

diff --git a/src/basic/reboot-util.c b/src/basic/reboot-util.c
new file mode 100644
index 000000000..2528d9bbe
--- /dev/null
+++ b/src/basic/reboot-util.c
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+//#include <errno.h>
+//#include <unistd.h>
+
+//#include "fileio.h"
+//#include "log.h"
+//#include "reboot-util.h"
+//#include "string-util.h"
+//#include "umask-util.h"
+
+int update_reboot_parameter_and_warn(const char *parameter) {
+        int r;
+
+        if (isempty(parameter)) {
+                if (unlink("/run/systemd/reboot-param") < 0) {
+                        if (errno == ENOENT)
+                                return 0;
+
+                        return log_warning_errno(errno, "Failed to unlink reboot parameter file: %m");
+                }
+
+                return 0;
+        }
+
+        RUN_WITH_UMASK(0022) {
+                r = write_string_file("/run/systemd/reboot-param", parameter,
+                                      WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
+                if (r < 0)
+                        return log_warning_errno(r, "Failed to write reboot parameter file: %m");
+        }
+
+        return 0;
+}