basic: add a common syscall wrapper around reboot()

This mimics the raw_clone() call we have in place already and
establishes a new syscall wrapper raw_reboot() that wraps the kernel's
reboot() system call in a bit more low-level fashion that glibc's
reboot() wrapper. The main difference is that the extra "arg" argument
is supported.

Ultimately this just replaces the syscall wrapper implementation we
currently have at three places in our codebase by a single one.

With this change this means that all our syscall() invocations are
neatly separated out in static inline system call wrappers in our header
functions.

5 files changed, 22 insertions, 8 deletions

diff --git a/src/basic/meson.build b/src/basic/meson.build
index d0e499d0d2..811085eec1 100644
--- a/src/basic/meson.build
+++ b/src/basic/meson.build
@@ -157,6 +157,7 @@ basic_sources = files('''
         ratelimit.c
         ratelimit.h
         raw-clone.h
+        raw-reboot.h
         refcnt.h
         replace-var.c
         replace-var.h
diff --git a/src/basic/raw-reboot.h b/src/basic/raw-reboot.h
new file mode 100644
index 0000000000..8ecefe9e21
--- /dev/null
+++ b/src/basic/raw-reboot.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <linux/reboot.h>
+#include <sys/reboot.h>
+#include <sys/syscall.h>
+
+/* glibc defines the reboot() API call, which is a wrapper around the system call of the same name, but without the
+ * extra "arg" parameter. Since we need that parameter for some calls, let's add a "raw" wrapper that is defined the
+ * same way, except it takes the additional argument. */
+
+static inline int raw_reboot(int cmd, const void *arg) {
+        return (int) syscall(SYS_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, arg);
+}
diff --git a/src/core/emergency-action.c b/src/core/emergency-action.c
index decfacd600..095033732b 100644
--- a/src/core/emergency-action.c
+++ b/src/core/emergency-action.c
@@ -20,11 +20,11 @@
 ***/
 
 #include <sys/reboot.h>
-#include <linux/reboot.h>
 
 #include "bus-error.h"
 #include "bus-util.h"
 #include "emergency-action.h"
+#include "raw-reboot.h"
 #include "special.h"
 #include "string-table.h"
 #include "terminal-util.h"
@@ -88,7 +88,7 @@ int emergency_action(
 
                 if (!isempty(reboot_arg)) {
                         log_info("Rebooting with argument '%s'.", reboot_arg);
-                        syscall(SYS_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_RESTART2, reboot_arg);
+                        (void) raw_reboot(LINUX_REBOOT_CMD_RESTART2, reboot_arg);
                         log_warning_errno(errno, "Failed to reboot with parameter, retrying without: %m");
                 }
 
diff --git a/src/core/shutdown.c b/src/core/shutdown.c
index 0326a7808d..8907c4b0a3 100644
--- a/src/core/shutdown.c
+++ b/src/core/shutdown.c
@@ -20,7 +20,6 @@
 
 #include <errno.h>
 #include <getopt.h>
-#include <linux/reboot.h>
 #include <signal.h>
 #include <stdbool.h>
 #include <stdlib.h>
@@ -42,6 +41,7 @@
 #include "missing.h"
 #include "parse-util.h"
 #include "process-util.h"
+#include "raw-reboot.h"
 #include "signal-util.h"
 #include "string-util.h"
 #include "switch-root.h"
@@ -528,7 +528,7 @@ int main(int argc, char *argv[]) {
 
                         if (!isempty(param)) {
                                 log_info("Rebooting with argument '%s'.", param);
-                                syscall(SYS_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_RESTART2, param);
+                                (void) raw_reboot(LINUX_REBOOT_CMD_RESTART2, param);
                                 log_warning_errno(errno, "Failed to reboot with parameter, retrying without: %m");
                         }
                 }
diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index 99ad2fc4b0..800f862938 100644
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -22,7 +22,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
-#include <linux/reboot.h>
 #include <locale.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -57,8 +56,8 @@
 #include "format-util.h"
 #include "fs-util.h"
 #include "glob-util.h"
-#include "hostname-util.h"
 #include "hexdecoct.h"
+#include "hostname-util.h"
 #include "initreq.h"
 #include "install.h"
 #include "io-util.h"
@@ -73,6 +72,7 @@
 #include "path-lookup.h"
 #include "path-util.h"
 #include "process-util.h"
+#include "raw-reboot.h"
 #include "rlimit-util.h"
 #include "set.h"
 #include "sigbus.h"
@@ -8514,8 +8514,7 @@ static int halt_now(enum action a) {
                         if (!arg_quiet)
                                 log_info("Rebooting with argument '%s'.", param);
                         if (!arg_dry_run) {
-                                (void) syscall(SYS_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
-                                               LINUX_REBOOT_CMD_RESTART2, param);
+                                (void) raw_reboot(LINUX_REBOOT_CMD_RESTART2, param);
                                 log_warning_errno(errno, "Failed to reboot with parameter, retrying without: %m");
                         }
                 }