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core: add io.systemd.Manager.{PowerOff,Reboot,SoftReboot,Halt,Kexec}

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This adds the low-level io.systemd.Manager shutdown support. This
is (much) simpler than the logind one. It mimics dbus but uses
a shared helper for the simple cases.

Note that this is more restrictive than the dbus version. The
dbus version uses SD_BUS_VTABLE_CAPABILITY(CAP_SYS_BOOT) but
the varlink version uses varlink_check_privileged_peer(link).
This is mostly because I'm not sure how to do the equivalent
in a race-free way.

Thanks to Daan for suggesting this.
This commit is contained in:
Michael Vogt
2026-03-21 22:01:17 +01:00
parent 55356a7821
commit 6215147624
5 changed files with 112 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/dbus-manager.c
+1
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@@ -1690,6 +1690,7 @@ static int method_soft_reboot(sd_bus_message *message, void *userdata, sd_bus_er
return sd_bus_error_set(reterr_error, SD_BUS_ERROR_NOT_SUPPORTED,
"Soft reboot is only supported by system manager.");
/* Keep the checks in sync with varlink-manager.c:vl_method_soft_reboot_manager() */
r = mac_selinux_access_check(message, "reboot", reterr_error);
if (r < 0)
return r;
src/core/varlink-manager.c
+82
View File
@@ -16,6 +16,7 @@
#include "glyph-util.h"
#include "json-util.h"
#include "manager.h"
#include "path-util.h"
#include "pidref.h"
#include "selinux-access.h"
#include "set.h"
@@ -398,3 +399,84 @@ int vl_method_enqueue_marked_jobs_manager(sd_varlink *link, sd_json_variant *par
return ret;
}
static int manager_do_set_objective(sd_varlink *link, sd_json_variant *parameters, ManagerObjective objective, const char *selinux_permission, bool can_do_root) {
Manager *m = ASSERT_PTR(sd_varlink_get_userdata(link));
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
_cleanup_free_ char *rt = NULL;
const char *root = NULL;
int r;
assert(link);
assert(parameters);
if (!MANAGER_IS_SYSTEM(m))
return sd_varlink_error(link, SD_VARLINK_ERROR_METHOD_NOT_IMPLEMENTED, NULL);
if (can_do_root) {
static const sd_json_dispatch_field dispatch_table[] = {
{ "root", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, 0, 0 },
{}
};
r = sd_varlink_dispatch(link, parameters, dispatch_table, &root);
} else
r = sd_varlink_dispatch(link, parameters, /* dispatch_table= */ NULL, /* userdata= */ NULL);
if (r != 0)
return r;
r = mac_selinux_access_check_varlink(link, selinux_permission);
if (r < 0)
return r;
/* dbus uses SD_BUS_VTABLE_CAPABILITY(CAP_SYS_BOOT) in its checking. We cannot do the same
* because reading capabilities from /proc is racy (TOCTOU). So we use the stricter check
* TODO: figure out a way to check for CAP_SYS_BOOT */
r = varlink_check_privileged_peer(link);
if (r < 0)
return r;
if (!isempty(root)) {
if (!path_is_valid(root))
return sd_varlink_error_invalid_parameter_name(link, "root");
if (!path_is_absolute(root))
return sd_varlink_error_invalid_parameter_name(link, "root");
r = path_simplify_alloc(root, &rt);
if (r < 0)
return r;
}
/* We need at least the pidref, otherwise there's nothing to log about. */
r = varlink_get_peer_pidref(link, &pidref);
if (r < 0)
log_debug_errno(r, "Failed to get peer pidref, ignoring: %m");
else
manager_log_caller(m, &pidref, manager_objective_to_string(objective));
if (can_do_root)
free_and_replace(m->switch_root, rt);
m->objective = objective;
return sd_varlink_reply(link, NULL);
}
int vl_method_poweroff_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
return manager_do_set_objective(link, parameters, MANAGER_POWEROFF, "halt", /* can_do_root= */ false);
}
int vl_method_reboot_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
return manager_do_set_objective(link, parameters, MANAGER_REBOOT, "reboot", /* can_do_root= */ false);
}
int vl_method_halt_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
return manager_do_set_objective(link, parameters, MANAGER_HALT, "halt", /* can_do_root= */ false);
}
int vl_method_kexec_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
return manager_do_set_objective(link, parameters, MANAGER_KEXEC, "reboot", /* can_do_root= */ false);
}
int vl_method_soft_reboot_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
return manager_do_set_objective(link, parameters, MANAGER_SOFT_REBOOT, "reboot", /* can_do_root= */ true);
}
src/core/varlink-manager.h
+5
View File
@@ -9,3 +9,8 @@ int vl_method_describe_manager(sd_varlink *link, sd_json_variant *parameters, sd
int vl_method_reexecute_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_reload_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_enqueue_marked_jobs_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_poweroff_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_reboot_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_halt_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_kexec_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
int vl_method_soft_reboot_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
src/core/varlink.c
+5
View File
@@ -390,6 +390,11 @@ int manager_setup_varlink_server(Manager *m) {
"io.systemd.Manager.Reexecute", vl_method_reexecute_manager,
"io.systemd.Manager.Reload", vl_method_reload_manager,
"io.systemd.Manager.EnqueueMarkedJobs", vl_method_enqueue_marked_jobs_manager,
"io.systemd.Manager.PowerOff", vl_method_poweroff_manager,
"io.systemd.Manager.Reboot", vl_method_reboot_manager,
"io.systemd.Manager.Halt", vl_method_halt_manager,
"io.systemd.Manager.KExec", vl_method_kexec_manager,
"io.systemd.Manager.SoftReboot", vl_method_soft_reboot_manager,
"io.systemd.Unit.List", vl_method_list_units,
"io.systemd.Unit.SetProperties", vl_method_set_unit_properties,
"io.systemd.service.Ping", varlink_method_ping,
src/shared/varlink-io.systemd.Manager.c
+19
View File
@@ -193,6 +193,15 @@ static SD_VARLINK_DEFINE_METHOD_FULL(
SD_VARLINK_FIELD_COMMENT("Job enqueue error message (on failure)"),
SD_VARLINK_DEFINE_OUTPUT(errorMessage, SD_VARLINK_STRING, SD_VARLINK_NULLABLE));
static SD_VARLINK_DEFINE_METHOD(PowerOff);
static SD_VARLINK_DEFINE_METHOD(Reboot);
static SD_VARLINK_DEFINE_METHOD(Halt);
static SD_VARLINK_DEFINE_METHOD(KExec);
static SD_VARLINK_DEFINE_METHOD(
SoftReboot,
SD_VARLINK_FIELD_COMMENT("New root directory for the soft reboot"),
SD_VARLINK_DEFINE_INPUT(root, SD_VARLINK_STRING, SD_VARLINK_NULLABLE));
static SD_VARLINK_DEFINE_ERROR(RateLimitReached);
SD_VARLINK_DEFINE_INTERFACE(
@@ -205,6 +214,16 @@ SD_VARLINK_DEFINE_INTERFACE(
&vl_method_Reload,
SD_VARLINK_SYMBOL_COMMENT("Enqueue all marked jobs"),
&vl_method_EnqueueMarkedJobs,
SD_VARLINK_SYMBOL_COMMENT("Power off the system"),
&vl_method_PowerOff,
SD_VARLINK_SYMBOL_COMMENT("Reboot the system"),
&vl_method_Reboot,
SD_VARLINK_SYMBOL_COMMENT("Halt the system"),
&vl_method_Halt,
SD_VARLINK_SYMBOL_COMMENT("Reboot the system via kexec"),
&vl_method_KExec,
SD_VARLINK_SYMBOL_COMMENT("Soft-reboot the userspace"),
&vl_method_SoftReboot,
&vl_error_RateLimitReached,
&vl_type_ManagerContext,
&vl_type_ManagerRuntime,