+/***
+ This file is part of elogind.
+
+ Copyright 2017 Sven Eden
+
+ elogind is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ elogind is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with elogind; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+
+#include "bus-util.h"
+#include "cgroup.h"
+#include "elogind.h"
+#include "fd-util.h"
+#include "mount-setup.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "umask-util.h"
+
+
+#define CGROUPS_AGENT_RCVBUF_SIZE (8*1024*1024)
+
+
+static int signal_agent_released(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+ _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
+ Manager *m = userdata;
+ const char *cgroup;
+ uid_t sender_uid;
+ int r;
+
+ assert(message);
+ assert(m);
+
+ /* only accept org.freedesktop.elogind.Agent from UID=0 */
+ r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_EUID, &creds);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_creds_get_euid(creds, &sender_uid);
+ if (r < 0 || sender_uid != 0)
+ return 0;
+
+ /* parse 'cgroup-empty' notification */
+ r = sd_bus_message_read(message, "s", &cgroup);
+ if (r < 0) {
+ bus_log_parse_error(r);
+ return 0;
+ }
+
+ manager_notify_cgroup_empty(m, cgroup);
+
+ return 0;
+}
+
+/// Add-On for manager_connect_bus()
+void elogind_bus_setup_system(Manager* m) {
+ int r;
+
+ assert(m);
+ assert(m->bus);
+
+ /* if we are a user instance we get the Released message via the system bus */
+ if (MANAGER_IS_USER(m)) {
+ r = sd_bus_add_match(
+ m->bus,
+ NULL,
+ "type='signal',"
+ "interface='org.freedesktop.elogind.Agent',"
+ "member='Released',"
+ "path='/org/freedesktop/elogind/agent'",
+ signal_agent_released, m);
+ if (r < 0)
+ log_warning_errno(r, "Failed to register Released match on system bus: %m");
+ }
+
+ log_debug("Successfully connected to system bus.");
+}
+
+static int bus_forward_agent_released(Manager *m, const char *path) {
+ int r;
+
+ assert(m);
+ assert(path);
+
+ if (!MANAGER_IS_SYSTEM(m))
+ return 0;
+
+ if (!m->bus)
+ return 0;
+
+ /* If we are running a system instance we forward the agent message on the system bus, so that the user
+ * instances get notified about this, too */
+
+ r = sd_bus_emit_signal(m->bus,
+ "/org/freedesktop/elogind/agent",
+ "org.freedesktop.elogind.Agent",
+ "Released",
+ "s", path);
+ if (r < 0)
+ return log_warning_errno(r, "Failed to propagate agent release message: %m");
+
+ return 1;
+}
+
+static int manager_dispatch_cgroups_agent_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+ char buf[PATH_MAX+1];
+ ssize_t n;
+
+ n = recv(fd, buf, sizeof(buf), 0);
+ if (n < 0)
+ return log_error_errno(errno, "Failed to read cgroups agent message: %m");
+ if (n == 0) {
+ log_error("Got zero-length cgroups agent message, ignoring.");
+ return 0;
+ }
+ if ((size_t) n >= sizeof(buf)) {
+ log_error("Got overly long cgroups agent message, ignoring.");
+ return 0;
+ }
+
+ if (memchr(buf, 0, n)) {
+ log_error("Got cgroups agent message with embedded NUL byte, ignoring.");
+ return 0;
+ }
+ buf[n] = 0;
+
+ manager_notify_cgroup_empty(m, buf);
+ bus_forward_agent_released(m, buf);
+
+ return 0;
+}
+
+/// Add-On for manager_connect_bus()
+int elogind_setup_cgroups_agent(Manager *m) {
+
+ static const union sockaddr_union sa = {
+ .un.sun_family = AF_UNIX,
+ .un.sun_path = "/run/systemd/cgroups-agent",
+ };
+ int r;
+
+ /* This creates a listening socket we receive cgroups agent messages on. We do not use D-Bus for delivering
+ * these messages from the cgroups agent binary to PID 1, as the cgroups agent binary is very short-living, and
+ * each instance of it needs a new D-Bus connection. Since D-Bus connections are SOCK_STREAM/AF_UNIX, on
+ * overloaded systems the backlog of the D-Bus socket becomes relevant, as not more than the configured number
+ * of D-Bus connections may be queued until the kernel will start dropping further incoming connections,
+ * possibly resulting in lost cgroups agent messages. To avoid this, we'll use a private SOCK_DGRAM/AF_UNIX
+ * socket, where no backlog is relevant as communication may take place without an actual connect() cycle, and
+ * we thus won't lose messages.
+ *
+ * Note that PID 1 will forward the agent message to system bus, so that the user systemd instance may listen
+ * to it. The system instance hence listens on this special socket, but the user instances listen on the system
+ * bus for these messages. */
+
+ if (m->test_run)
+ return 0;
+
+ if (!MANAGER_IS_SYSTEM(m))
+ return 0;
+
+ if (cg_unified() > 0) /* We don't need this anymore on the unified hierarchy */
+ return 0;
+
+ if (m->cgroups_agent_fd < 0) {
+ _cleanup_close_ int fd = -1;
+
+ /* First free all secondary fields */
+ m->cgroups_agent_event_source = sd_event_source_unref(m->cgroups_agent_event_source);
+
+ fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (fd < 0)
+ return log_error_errno(errno, "Failed to allocate cgroups agent socket: %m");
+
+ fd_inc_rcvbuf(fd, CGROUPS_AGENT_RCVBUF_SIZE);
+
+ (void) unlink(sa.un.sun_path);
+
+ /* Only allow root to connect to this socket */
+ RUN_WITH_UMASK(0077)
+ r = bind(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
+ if (r < 0)
+ return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
+
+ m->cgroups_agent_fd = fd;
+ fd = -1;
+ }
+
+ if (!m->cgroups_agent_event_source) {
+ r = sd_event_add_io(m->event, &m->cgroups_agent_event_source, m->cgroups_agent_fd, EPOLLIN, manager_dispatch_cgroups_agent_fd, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to allocate cgroups agent event source: %m");
+
+ /* Process cgroups notifications early, but after having processed service notification messages or
+ * SIGCHLD signals, so that a cgroup running empty is always just the last safety net of notification,
+ * and we collected the metadata the notification and SIGCHLD stuff offers first. Also see handling of
+ * cgroup inotify for the unified cgroup stuff. */
+ r = sd_event_source_set_priority(m->cgroups_agent_event_source, SD_EVENT_PRIORITY_NORMAL-5);
+ if (r < 0)
+ return log_error_errno(r, "Failed to set priority of cgroups agent event source: %m");
+
+ (void) sd_event_source_set_description(m->cgroups_agent_event_source, "manager-cgroups-agent");
+ }
+
+ return 0;
+}
+
+/// Add-On for manager_free()
+void elogind_manager_free(Manager* m) {
+
+ manager_shutdown_cgroup(m, true);
+
+ sd_event_source_unref(m->cgroups_agent_event_source);
+
+ safe_close(m->cgroups_agent_fd);
+
+ strv_free(m->suspend_mode);
+ strv_free(m->suspend_state);
+ strv_free(m->hibernate_mode);
+ strv_free(m->hibernate_state);
+ strv_free(m->hybrid_sleep_mode);
+ strv_free(m->hybrid_sleep_state);
+}
+
+/// Add-On for manager_new()
+int elogind_manager_new(Manager* m) {
+ int r = 0;
+
+ m->cgroups_agent_fd = -1;
+ m->pin_cgroupfs_fd = -1;
+ m->test_run = false;
+
+ /* Init sleep modes and states */
+ m->suspend_mode = NULL;
+ m->suspend_state = NULL;
+ m->hibernate_mode = NULL;
+ m->hibernate_state = NULL;
+ m->hybrid_sleep_mode = NULL;
+ m->hybrid_sleep_state = NULL;
+
+ /* If elogind should be its own controller, mount its cgroup */
+ if (streq(SYSTEMD_CGROUP_CONTROLLER, "name=elogind")) {
+ m->is_system = true;
+ r = mount_setup(true);
+ } else
+ m->is_system = false;
+
+ /* Make cgroups */
+ if (r > -1)
+ r = manager_setup_cgroup(m);
+
+ return r;
+}
+
+/// Add-On for manager_reset_config()
+void elogind_manager_reset_config(Manager* m) {
+
+#ifdef ENABLE_DEBUG_ELOGIND
+ int dbg_cnt;
+#endif // ENABLE_DEBUG_ELOGIND
+
+ /* Set default Sleep config if not already set by logind.conf */
+ if (!m->suspend_state)
+ m->suspend_state = strv_new("mem", "standby", "freeze", NULL);
+ if (!m->hibernate_mode)
+ m->hibernate_mode = strv_new("platform", "shutdown", NULL);
+ if (!m->hibernate_state)
+ m->hibernate_state = strv_new("disk", NULL);
+ if (!m->hybrid_sleep_mode)
+ m->hybrid_sleep_mode = strv_new("suspend", "platform", "shutdown", NULL);
+ if (!m->hybrid_sleep_state)
+ m->hybrid_sleep_state = strv_new("disk", NULL);
+
+#ifdef ENABLE_DEBUG_ELOGIND
+ dbg_cnt = -1;
+ while (m->suspend_mode && m->suspend_mode[++dbg_cnt])
+ log_debug_elogind("suspend_mode[%d] = %s",
+ dbg_cnt, m->suspend_mode[dbg_cnt]);
+ dbg_cnt = -1;
+ while (m->suspend_state[++dbg_cnt])
+ log_debug_elogind("suspend_state[%d] = %s",
+ dbg_cnt, m->suspend_state[dbg_cnt]);
+ dbg_cnt = -1;
+ while (m->hibernate_mode[++dbg_cnt])
+ log_debug_elogind("hibernate_mode[%d] = %s",
+ dbg_cnt, m->hibernate_mode[dbg_cnt]);
+ dbg_cnt = -1;
+ while (m->hibernate_state[++dbg_cnt])
+ log_debug_elogind("hibernate_state[%d] = %s",
+ dbg_cnt, m->hibernate_state[dbg_cnt]);
+ dbg_cnt = -1;
+ while (m->hybrid_sleep_mode[++dbg_cnt])
+ log_debug_elogind("hybrid_sleep_mode[%d] = %s",
+ dbg_cnt, m->hybrid_sleep_mode[dbg_cnt]);
+ dbg_cnt = -1;
+ while (m->hybrid_sleep_state[++dbg_cnt])
+ log_debug_elogind("hybrid_sleep_state[%d] = %s",
+ dbg_cnt, m->hybrid_sleep_state[dbg_cnt]);
+#endif // ENABLE_DEBUG_ELOGIND
+}
~ianmdlvl / elogind.git / commitdiff