core: rework reboot parameter logic a bit

Always warn if something fails, and clarify that the involved utility functions
do so in their name.

Drop the REBOOT_PARAM_FILE macro. We don't do this for other flag file paths
like this, so don't do this for this one either. The path isn't configurable
anyway, hence let's make this easier to read by avoiding this one indirection.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/core/shutdown.c b/src/core/shutdown.c
index 96679c920f..e14755d84e 100644
--- a/src/core/shutdown.c
+++ b/src/core/shutdown.c
@@ -397,9 +397,14 @@ int main(int argc, char *argv[]) {
                 if (!in_container) {
                         _cleanup_free_ char *param = NULL;
 
-                        if (read_one_line_file(REBOOT_PARAM_FILE, &param) >= 0) {
+                        r = read_one_line_file("/run/systemd/reboot-param", &param);
+                        if (r < 0)
+                                log_warning_errno(r, "Failed to read reboot parameter file: %m");
+
+                        if (!isempty(param)) {
                                 log_info("Rebooting with argument '%s'.", param);
                                 syscall(SYS_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_RESTART2, param);
+                                log_warning_errno(errno, "Failed to reboot with parameter, retrying without: %m");
                         }
                 }