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/* 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-error.h"
#include "bus-locator.h"
#include "bus-unit-util.h"
#include "bus-util.h"
#include "constants.h"
#include "env-util.h"
#include "initrd-util.h"
#include "log.h"
#include "main-func.h"
#include "proc-cmdline.h"
#include "process-util.h"
#include "signal-util.h"
#include "special.h"
#include "unit-def.h"
static int target_is_inactive(sd_bus *bus, const char *target) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_free_ char *path = NULL, *state = NULL;
int r;
path = unit_dbus_path_from_name(target);
if (!path)
return log_oom();
r = sd_bus_get_property_string(bus,
"org.freedesktop.systemd1",
path,
"org.freedesktop.systemd1.Unit",
"ActiveState",
&error,
&state);
if (r < 0)
return log_error_errno(r, "Failed to retrieve unit state: %s", bus_error_message(&error, r));
return streq_ptr(state, "inactive");
}
static int start_target(sd_bus *bus, const char *target) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
int r;
log_info("Starting %s", 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", target, "isolate");
if (r < 0)
return log_error_errno(r, "Failed to start %s: %s", target, 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_SIGTERM|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, or \"exit\"\n" "to continue bootup.\n", mode);
fflush(stdout);
}
static int run(int argc, char *argv[]) {
const char* sulogin_cmdline[] = {
SULOGIN,
NULL, /* --force */
NULL
};
bool force = false;
int r;
log_setup();
print_mode(argc > 1 ? argv[1] : "");
if (getenv_bool("SYSTEMD_SULOGIN_FORCE") > 0)
force = true;
if (!force) {
/* We look the argument in the kernel cmdline under the same name as the environment variable
* to express that this is not supported at the same level as the regular kernel cmdline
* switches. */
r = proc_cmdline_get_bool("SYSTEMD_SULOGIN_FORCE", /* flags = */ 0, &force);
if (r < 0)
log_debug_errno(r, "Failed to parse SYSTEMD_SULOGIN_FORCE from kernel command line, ignoring: %m");
}
if (force)
/* allows passwordless logins if root account is locked. */
sulogin_cmdline[1] = "--force";
for (;;) {
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
(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");
goto fallback;
}
log_info("Reloading system manager configuration.");
r = bus_service_manager_reload(bus);
if (r < 0)
goto fallback;
const char *target = in_initrd() ? SPECIAL_INITRD_TARGET : SPECIAL_DEFAULT_TARGET;
r = target_is_inactive(bus, target);
if (r < 0)
goto fallback;
if (!r) {
log_warning("%s is not inactive. Please review the %s setting.", target, target);
goto fallback;
}
if (start_target(bus, target) >= 0)
break;
fallback:
log_warning("Fallback to the single-user shell.");
}
return 0;
}
DEFINE_MAIN_FUNCTION(run);
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