out o unit);
GetUnitByControlGroup(in s cgroup,
out o unit);
+ GetUnitByPIDFD(in h pidfd,
+ out o unit,
+ out s unit_id,
+ out ay invocation_id);
LoadUnit(in s name,
out o unit);
StartUnit(in s name,
<variablelist class="dbus-method" generated="True" extra-ref="GetUnitByControlGroup()"/>
+ <variablelist class="dbus-method" generated="True" extra-ref="GetUnitByPIDFD()"/>
+
<variablelist class="dbus-method" generated="True" extra-ref="LoadUnit()"/>
<variablelist class="dbus-method" generated="True" extra-ref="StartUnit()"/>
will fail.</para>
<para><function>GetUnitByPID()</function> may be used to get the unit object path of the unit a process
- ID belongs to. It takes a UNIX PID and returns the object path. The PID must refer to an existing system process.</para>
+ ID belongs to. It takes a UNIX PID and returns the object path. The PID must refer to an existing system process.
+ <function>GetUnitByPIDFD()</function> may be used to query with a Linux PIDFD (see:
+ <citerefentry><refentrytitle>pidfd_open</refentrytitle><manvolnum>2</manvolnum></citerefentry>) instead
+ of a PID, which is safer as UNIX PIDs can be recycled. The latter method returns the unit id and the
+ invocation id together with the unit object path.</para>
<para><function>LoadUnit()</function> is similar to <function>GetUnit()</function> but will load the
unit from disk if possible.</para>
return reply_unit_path(u, message, error);
}
+static int method_get_unit_by_pidfd(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+ Manager *m = ASSERT_PTR(userdata);
+ _cleanup_free_ char *path = NULL;
+ int r, pidfd;
+ pid_t pid_early, pid_late;
+ Unit *u;
+
+ assert(message);
+
+ r = sd_bus_message_read(message, "h", &pidfd);
+ if (r < 0)
+ return r;
+
+ r = pidfd_get_pid(pidfd, &pid_early);
+ if (r < 0)
+ return sd_bus_error_set_errnof(error, r, "Failed to get PID from PIDFD: %m");
+
+ u = manager_get_unit_by_pid(m, pid_early);
+ if (!u)
+ return sd_bus_error_setf(error, BUS_ERROR_NO_UNIT_FOR_PID, "PID "PID_FMT" does not belong to any loaded unit.", pid_early);
+
+ r = mac_selinux_unit_access_check(u, message, "status", error);
+ if (r < 0)
+ return r;
+
+ path = unit_dbus_path(u);
+ if (!path)
+ return log_oom();
+
+ r = sd_bus_message_new_method_return(message, &reply);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(reply, "os", path, u->id);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append_array(reply, 'y', u->invocation_id.bytes, sizeof(u->invocation_id.bytes));
+ if (r < 0)
+ return r;
+
+ /* Double-check that the process is still alive and that the PID did not change before returning the
+ * answer. */
+ r = pidfd_get_pid(pidfd, &pid_late);
+ if (r < 0)
+ return sd_bus_error_set_errnof(error, r, "Failed to get PID from PIDFD: %m");
+ if (pid_early != pid_late)
+ return sd_bus_error_setf(error,
+ BUS_ERROR_NO_SUCH_PROCESS,
+ "The PIDFD's PID "PID_FMT" changed to "PID_FMT" during the lookup operation.",
+ pid_early,
+ pid_late);
+
+ return sd_bus_send(NULL, reply, NULL);
+}
+
static int method_load_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
Manager *m = ASSERT_PTR(userdata);
const char *name;
SD_BUS_RESULT("o", unit),
method_get_unit_by_control_group,
SD_BUS_VTABLE_UNPRIVILEGED),
+ SD_BUS_METHOD_WITH_ARGS("GetUnitByPIDFD",
+ SD_BUS_ARGS("h", pidfd),
+ SD_BUS_RESULT("o", unit, "s", unit_id, "ay", invocation_id),
+ method_get_unit_by_pidfd,
+ SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD_WITH_ARGS("LoadUnit",
SD_BUS_ARGS("s", name),
SD_BUS_RESULT("o", unit),
send_interface="org.freedesktop.systemd1.Manager"
send_member="GetUnitByControlGroup"/>
+ <allow send_destination="org.freedesktop.systemd1"
+ send_interface="org.freedesktop.systemd1.Manager"
+ send_member="GetUnitByPIDFD"/>
+
<allow send_destination="org.freedesktop.systemd1"
send_interface="org.freedesktop.systemd1.Manager"
send_member="LoadUnit"/>
#include "errno-util.h"
#include "exec-util.h"
#include "exit-status.h"
+#include "fd-util.h"
#include "format-util.h"
#include "hexdecoct.h"
#include "hostname-util.h"
return 0;
}
-static int get_unit_dbus_path_by_pid(
+static int get_unit_dbus_path_by_pid_fallback(
sd_bus *bus,
uint32_t pid,
- char **unit) {
+ char **ret_path,
+ char **ret_unit) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
- char *u;
+ _cleanup_free_ char *path = NULL, *unit = NULL;
+ char *p;
int r;
+ assert(bus);
+ assert(ret_path);
+ assert(ret_unit);
+
r = bus_call_method(bus, bus_systemd_mgr, "GetUnitByPID", &error, &reply, "u", pid);
if (r < 0)
return log_error_errno(r, "Failed to get unit for PID %"PRIu32": %s", pid, bus_error_message(&error, r));
- r = sd_bus_message_read(reply, "o", &u);
+ r = sd_bus_message_read(reply, "o", &p);
+ if (r < 0)
+ return bus_log_parse_error(r);
+
+ path = strdup(p);
+ if (!path)
+ return log_oom();
+
+ r = unit_name_from_dbus_path(path, &unit);
+ if (r < 0)
+ return log_oom();
+
+ *ret_unit = TAKE_PTR(unit);
+ *ret_path = TAKE_PTR(path);
+
+ return 0;
+}
+
+static int get_unit_dbus_path_by_pid(
+ sd_bus *bus,
+ uint32_t pid,
+ char **ret_path,
+ char **ret_unit) {
+
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+ _cleanup_free_ char *path = NULL, *unit = NULL;
+ _cleanup_close_ int pidfd = -EBADFD;
+ char *p, *u;
+ int r;
+
+ assert(bus);
+ assert(ret_path);
+ assert(ret_unit);
+
+ /* First, try to send a PIDFD across the wire, so that we can pin the process and there's no race
+ * condition possible while we wait for the D-Bus reply. If we either don't have PIDFD support in
+ * the kernel or the new D-Bus method is not available, then fallback to the older method that
+ * sends the numeric PID. */
+
+ pidfd = pidfd_open(pid, 0);
+ if (pidfd < 0 && ERRNO_IS_NOT_SUPPORTED(errno))
+ return get_unit_dbus_path_by_pid_fallback(bus, pid, ret_path, ret_unit);
+ if (pidfd < 0)
+ return log_error_errno(errno, "Failed to open PID %"PRIu32": %m", pid);
+
+ r = bus_call_method(bus, bus_systemd_mgr, "GetUnitByPIDFD", &error, &reply, "h", pidfd);
+ if (r < 0 && sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD))
+ return get_unit_dbus_path_by_pid_fallback(bus, pid, ret_path, ret_unit);
+ if (r < 0)
+ return log_error_errno(r, "Failed to get unit for PID %"PRIu32": %s", pid, bus_error_message(&error, r));
+
+ r = sd_bus_message_read(reply, "os", &p, &u);
if (r < 0)
return bus_log_parse_error(r);
- u = strdup(u);
- if (!u)
+ path = strdup(p);
+ if (!path)
+ return log_oom();
+
+ unit = strdup(u);
+ if (!unit)
return log_oom();
- *unit = u;
+ *ret_unit = TAKE_PTR(unit);
+ *ret_path = TAKE_PTR(path);
+
return 0;
}
} else {
/* Interpret as PID */
- r = get_unit_dbus_path_by_pid(bus, id, &path);
+ r = get_unit_dbus_path_by_pid(bus, id, &path, &unit);
if (r < 0) {
ret = r;
continue;
}
-
- r = unit_name_from_dbus_path(path, &unit);
- if (r < 0)
- return log_oom();
}
r = show_one(bus, path, unit, show_mode, &new_line, &ellipsized);
systemctl status "systemd-journald*.socket"
systemctl status "sys-devices-*-ttyS0.device"
systemctl status -- -.mount
+systemctl status 1
# --marked
systemctl restart "$UNIT_NAME"
projects / thirdparty / systemd.git / commitdiff
