1 files changed, 119 insertions, 0 deletions
diff --git a/src/sulogin-shell/sulogin-shell.c b/src/sulogin-shell/sulogin-shell.c
new file mode 100644
index 0000000..5648dfd
--- /dev/null
+++ b/src/sulogin-shell/sulogin-shell.c
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2017 Felipe Sateler
+***/
+
+#include <errno.h>
+#include <sys/prctl.h>
+
+#include "sd-bus.h"
+
+#include "bus-locator.h"
+#include "bus-util.h"
+#include "bus-error.h"
+#include "def.h"
+#include "env-util.h"
+#include "log.h"
+#include "process-util.h"
+#include "signal-util.h"
+#include "special.h"
+
+static int reload_manager(sd_bus *bus) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        log_info("Reloading system manager configuration");
+
+        r = bus_message_new_method_call(
+                        bus,
+                        &m,
+                        bus_systemd_mgr,
+                        "Reload");
+        if (r < 0)
+                return bus_log_create_error(r);
+
+        /* Reloading the daemon may take long, hence set a longer timeout here */
+        r = sd_bus_call(bus, m, DAEMON_RELOAD_TIMEOUT_SEC, &error, NULL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to reload daemon: %s", bus_error_message(&error, r));
+
+        return 0;
+}
+
+static int start_default_target(sd_bus *bus) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        int r;
+
+        log_info("Starting "SPECIAL_DEFAULT_TARGET);
+
+        /* Start this unit only if we can replace basic.target with it */
+        r = bus_call_method(
+                        bus,
+                        bus_systemd_mgr,
+                        "StartUnit",
+                        &error,
+                        NULL,
+                        "ss", SPECIAL_DEFAULT_TARGET, "isolate");
+
+        if (r < 0)
+                return log_error_errno(r, "Failed to start "SPECIAL_DEFAULT_TARGET": %s", bus_error_message(&error, r));
+
+        return 0;
+}
+
+static int fork_wait(const char* const cmdline[]) {
+        pid_t pid;
+        int r;
+
+        r = safe_fork("(sulogin)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_RLIMIT_NOFILE_SAFE|FORK_LOG, &pid);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                /* Child */
+                execv(cmdline[0], (char**) cmdline);
+                log_error_errno(errno, "Failed to execute %s: %m", cmdline[0]);
+                _exit(EXIT_FAILURE); /* Operational error */
+        }
+
+        return wait_for_terminate_and_check(cmdline[0], pid, WAIT_LOG_ABNORMAL);
+}
+
+static void print_mode(const char* mode) {
+        printf("You are in %s mode. After logging in, type \"journalctl -xb\" to view\n"
+                "system logs, \"systemctl reboot\" to reboot, \"systemctl default\" or \"exit\"\n"
+                "to boot into default mode.\n", mode);
+        fflush(stdout);
+}
+
+int main(int argc, char *argv[]) {
+        const char* sulogin_cmdline[] = {
+                SULOGIN,
+                NULL,             /* --force */
+                NULL
+        };
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        int r;
+
+        log_setup();
+
+        print_mode(argc > 1 ? argv[1] : "");
+
+        if (getenv_bool("SYSTEMD_SULOGIN_FORCE") > 0)
+                /* allows passwordless logins if root account is locked. */
+                sulogin_cmdline[1] = "--force";
+
+        (void) fork_wait(sulogin_cmdline);
+
+        r = bus_connect_system_systemd(&bus);
+        if (r < 0) {
+                log_warning_errno(r, "Failed to get D-Bus connection: %m");
+                r = 0;
+        } else {
+                (void) reload_manager(bus);
+
+                r = start_default_target(bus);
+        }
+
+        return r >= 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}