Adding upstream version 2.1.6.upstream/2.1.6

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1100 insertions, 0 deletions

diff --git a/lib/services/systemd.c b/lib/services/systemd.c
new file mode 100644
index 0000000..0c38ae0
--- /dev/null
+++ b/lib/services/systemd.c
@@ -0,0 +1,1100 @@
+/*
+ * Copyright 2012-2022 the Pacemaker project contributors
+ *
+ * The version control history for this file may have further details.
+ *
+ * This source code is licensed under the GNU Lesser General Public License
+ * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
+ */
+
+#include <crm_internal.h>
+#include <crm/crm.h>
+#include <crm/services.h>
+#include <crm/services_internal.h>
+#include <crm/common/mainloop.h>
+
+#include <sys/stat.h>
+#include <gio/gio.h>
+#include <services_private.h>
+#include <systemd.h>
+#include <dbus/dbus.h>
+#include <pcmk-dbus.h>
+
+static void invoke_unit_by_path(svc_action_t *op, const char *unit);
+
+#define BUS_NAME         "org.freedesktop.systemd1"
+#define BUS_NAME_MANAGER BUS_NAME ".Manager"
+#define BUS_NAME_UNIT    BUS_NAME ".Unit"
+#define BUS_PATH         "/org/freedesktop/systemd1"
+
+/*!
+ * \internal
+ * \brief Prepare a systemd action
+ *
+ * \param[in,out] op  Action to prepare
+ *
+ * \return Standard Pacemaker return code
+ */
+int
+services__systemd_prepare(svc_action_t *op)
+{
+    op->opaque->exec = strdup("systemd-dbus");
+    if (op->opaque->exec == NULL) {
+        return ENOMEM;
+    }
+    return pcmk_rc_ok;
+}
+
+/*!
+ * \internal
+ * \brief Map a systemd result to a standard OCF result
+ *
+ * \param[in] exit_status  Systemd result
+ *
+ * \return Standard OCF result
+ */
+enum ocf_exitcode
+services__systemd2ocf(int exit_status)
+{
+    // This library uses OCF codes for systemd actions
+    return (enum ocf_exitcode) exit_status;
+}
+
+static inline DBusMessage *
+systemd_new_method(const char *method)
+{
+    crm_trace("Calling: %s on " BUS_NAME_MANAGER, method);
+    return dbus_message_new_method_call(BUS_NAME, BUS_PATH, BUS_NAME_MANAGER,
+                                        method);
+}
+
+/*
+ * Functions to manage a static DBus connection
+ */
+
+static DBusConnection* systemd_proxy = NULL;
+
+static inline DBusPendingCall *
+systemd_send(DBusMessage *msg,
+             void(*done)(DBusPendingCall *pending, void *user_data),
+             void *user_data, int timeout)
+{
+    return pcmk_dbus_send(msg, systemd_proxy, done, user_data, timeout);
+}
+
+static inline DBusMessage *
+systemd_send_recv(DBusMessage *msg, DBusError *error, int timeout)
+{
+    return pcmk_dbus_send_recv(msg, systemd_proxy, error, timeout);
+}
+
+/*!
+ * \internal
+ * \brief Send a method to systemd without arguments, and wait for reply
+ *
+ * \param[in] method  Method to send
+ *
+ * \return Systemd reply on success, NULL (and error will be logged) otherwise
+ *
+ * \note The caller must call dbus_message_unref() on the reply after
+ *       handling it.
+ */
+static DBusMessage *
+systemd_call_simple_method(const char *method)
+{
+    DBusMessage *msg = systemd_new_method(method);
+    DBusMessage *reply = NULL;
+    DBusError error;
+
+    /* Don't call systemd_init() here, because that calls this */
+    CRM_CHECK(systemd_proxy, return NULL);
+
+    if (msg == NULL) {
+        crm_err("Could not create message to send %s to systemd", method);
+        return NULL;
+    }
+
+    dbus_error_init(&error);
+    reply = systemd_send_recv(msg, &error, DBUS_TIMEOUT_USE_DEFAULT);
+    dbus_message_unref(msg);
+
+    if (dbus_error_is_set(&error)) {
+        crm_err("Could not send %s to systemd: %s (%s)",
+                method, error.message, error.name);
+        dbus_error_free(&error);
+        return NULL;
+
+    } else if (reply == NULL) {
+        crm_err("Could not send %s to systemd: no reply received", method);
+        return NULL;
+    }
+
+    return reply;
+}
+
+static gboolean
+systemd_init(void)
+{
+    static int need_init = 1;
+    // https://dbus.freedesktop.org/doc/api/html/group__DBusConnection.html
+
+    if (systemd_proxy
+        && dbus_connection_get_is_connected(systemd_proxy) == FALSE) {
+        crm_warn("Connection to System DBus is closed. Reconnecting...");
+        pcmk_dbus_disconnect(systemd_proxy);
+        systemd_proxy = NULL;
+        need_init = 1;
+    }
+
+    if (need_init) {
+        need_init = 0;
+        systemd_proxy = pcmk_dbus_connect();
+    }
+    if (systemd_proxy == NULL) {
+        return FALSE;
+    }
+    return TRUE;
+}
+
+static inline char *
+systemd_get_property(const char *unit, const char *name,
+                     void (*callback)(const char *name, const char *value, void *userdata),
+                     void *userdata, DBusPendingCall **pending, int timeout)
+{
+    return systemd_proxy?
+           pcmk_dbus_get_property(systemd_proxy, BUS_NAME, unit, BUS_NAME_UNIT,
+                                  name, callback, userdata, pending, timeout)
+           : NULL;
+}
+
+void
+systemd_cleanup(void)
+{
+    if (systemd_proxy) {
+        pcmk_dbus_disconnect(systemd_proxy);
+        systemd_proxy = NULL;
+    }
+}
+
+/*
+ * end of systemd_proxy functions
+ */
+
+/*!
+ * \internal
+ * \brief Check whether a file name represents a manageable systemd unit
+ *
+ * \param[in] name  File name to check
+ *
+ * \return Pointer to "dot" before filename extension if so, NULL otherwise
+ */
+static const char *
+systemd_unit_extension(const char *name)
+{
+    if (name) {
+        const char *dot = strrchr(name, '.');
+
+        if (dot && (!strcmp(dot, ".service")
+                    || !strcmp(dot, ".socket")
+                    || !strcmp(dot, ".mount")
+                    || !strcmp(dot, ".timer")
+                    || !strcmp(dot, ".path"))) {
+            return dot;
+        }
+    }
+    return NULL;
+}
+
+static char *
+systemd_service_name(const char *name, bool add_instance_name)
+{
+    const char *dot = NULL;
+
+    if (pcmk__str_empty(name)) {
+        return NULL;
+    }
+
+    /* Services that end with an @ sign are systemd templates.  They expect an
+     * instance name to follow the service name.  If no instance name was
+     * provided, just add "pacemaker" to the string as the instance name.  It
+     * doesn't seem to matter for purposes of looking up whether a service
+     * exists or not.
+     *
+     * A template can be specified either with or without the unit extension,
+     * so this block handles both cases.
+     */
+    dot = systemd_unit_extension(name);
+
+    if (dot) {
+        if (dot != name && *(dot-1) == '@') {
+            char *s = NULL;
+
+            if (asprintf(&s, "%.*spacemaker%s", (int) (dot-name), name, dot) == -1) {
+                /* If asprintf fails, just return name. */
+                return strdup(name);
+            }
+
+            return s;
+        } else {
+            return strdup(name);
+        }
+
+    } else if (add_instance_name && *(name+strlen(name)-1) == '@') {
+        return crm_strdup_printf("%spacemaker.service", name);
+
+    } else {
+        return crm_strdup_printf("%s.service", name);
+    }
+}
+
+static void
+systemd_daemon_reload_complete(DBusPendingCall *pending, void *user_data)
+{
+    DBusError error;
+    DBusMessage *reply = NULL;
+    unsigned int reload_count = GPOINTER_TO_UINT(user_data);
+
+    dbus_error_init(&error);
+    if(pending) {
+        reply = dbus_pending_call_steal_reply(pending);
+    }
+
+    if (pcmk_dbus_find_error(pending, reply, &error)) {
+        crm_warn("Could not issue systemd reload %d: %s",
+                 reload_count, error.message);
+        dbus_error_free(&error);
+
+    } else {
+        crm_trace("Reload %d complete", reload_count);
+    }
+
+    if(pending) {
+        dbus_pending_call_unref(pending);
+    }
+    if(reply) {
+        dbus_message_unref(reply);
+    }
+}
+
+static bool
+systemd_daemon_reload(int timeout)
+{
+    static unsigned int reload_count = 0;
+    DBusMessage *msg = systemd_new_method("Reload");
+
+    reload_count++;
+    CRM_ASSERT(msg != NULL);
+    systemd_send(msg, systemd_daemon_reload_complete,
+                 GUINT_TO_POINTER(reload_count), timeout);
+    dbus_message_unref(msg);
+
+    return TRUE;
+}
+
+/*!
+ * \internal
+ * \brief Set an action result based on a method error
+ *
+ * \param[in,out] op     Action to set result for
+ * \param[in]     error  Method error
+ */
+static void
+set_result_from_method_error(svc_action_t *op, const DBusError *error)
+{
+    services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                         "Unable to invoke systemd DBus method");
+
+    if (strstr(error->name, "org.freedesktop.systemd1.InvalidName")
+        || strstr(error->name, "org.freedesktop.systemd1.LoadFailed")
+        || strstr(error->name, "org.freedesktop.systemd1.NoSuchUnit")) {
+
+        if (pcmk__str_eq(op->action, "stop", pcmk__str_casei)) {
+            crm_trace("Masking systemd stop failure (%s) for %s "
+                      "because unknown service can be considered stopped",
+                      error->name, pcmk__s(op->rsc, "unknown resource"));
+            services__set_result(op, PCMK_OCF_OK, PCMK_EXEC_DONE, NULL);
+            return;
+        }
+
+        services__format_result(op, PCMK_OCF_NOT_INSTALLED,
+                               PCMK_EXEC_NOT_INSTALLED,
+                               "systemd unit %s not found", op->agent);
+    }
+
+    crm_info("DBus request for %s of systemd unit %s%s%s failed: %s",
+             op->action, op->agent,
+             ((op->rsc == NULL)? "" : " for resource "), pcmk__s(op->rsc, ""),
+             error->message);
+}
+
+/*!
+ * \internal
+ * \brief Extract unit path from LoadUnit reply, and execute action
+ *
+ * \param[in]     reply  LoadUnit reply
+ * \param[in,out] op     Action to execute (or NULL to just return path)
+ *
+ * \return DBus object path for specified unit if successful (only valid for
+ *         lifetime of \p reply), otherwise NULL
+ */
+static const char *
+execute_after_loadunit(DBusMessage *reply, svc_action_t *op)
+{
+    const char *path = NULL;
+    DBusError error;
+
+    /* path here is not used other than as a non-NULL flag to indicate that a
+     * request was indeed sent
+     */
+    if (pcmk_dbus_find_error((void *) &path, reply, &error)) {
+        if (op != NULL) {
+            set_result_from_method_error(op, &error);
+        }
+        dbus_error_free(&error);
+
+    } else if (!pcmk_dbus_type_check(reply, NULL, DBUS_TYPE_OBJECT_PATH,
+                                     __func__, __LINE__)) {
+        if (op != NULL) {
+            services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                                 "systemd DBus method had unexpected reply");
+            crm_info("Could not load systemd unit %s for %s: "
+                     "DBus reply has unexpected type", op->agent, op->id);
+        } else {
+            crm_info("Could not load systemd unit: "
+                     "DBus reply has unexpected type");
+        }
+
+    } else {
+        dbus_message_get_args (reply, NULL,
+                               DBUS_TYPE_OBJECT_PATH, &path,
+                               DBUS_TYPE_INVALID);
+    }
+
+    if (op != NULL) {
+        if (path != NULL) {
+            invoke_unit_by_path(op, path);
+
+        } else if (!(op->synchronous)) {
+            services__format_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                                    "No DBus object found for systemd unit %s",
+                                    op->agent);
+            services__finalize_async_op(op);
+        }
+    }
+
+    return path;
+}
+
+/*!
+ * \internal
+ * \brief Execute a systemd action after its LoadUnit completes
+ *
+ * \param[in,out] pending    If not NULL, DBus call associated with LoadUnit
+ * \param[in,out] user_data  Action to execute
+ */
+static void
+loadunit_completed(DBusPendingCall *pending, void *user_data)
+{
+    DBusMessage *reply = NULL;
+    svc_action_t *op = user_data;
+
+    crm_trace("LoadUnit result for %s arrived", op->id);
+
+    // Grab the reply
+    if (pending != NULL) {
+        reply = dbus_pending_call_steal_reply(pending);
+    }
+
+    // The call is no longer pending
+    CRM_LOG_ASSERT(pending == op->opaque->pending);
+    services_set_op_pending(op, NULL);
+
+    // Execute the desired action based on the reply
+    execute_after_loadunit(reply, user_data);
+    if (reply != NULL) {
+        dbus_message_unref(reply);
+    }
+}
+
+/*!
+ * \internal
+ * \brief Execute a systemd action, given the unit name
+ *
+ * \param[in]     arg_name  Unit name (possibly without ".service" extension)
+ * \param[in,out] op        Action to execute (if NULL, just get object path)
+ * \param[out]    path      If non-NULL and \p op is NULL or synchronous, where
+ *                          to store DBus object path for specified unit
+ *
+ * \return Standard Pacemaker return code (for NULL \p op, pcmk_rc_ok means unit
+ *         was found; for synchronous actions, pcmk_rc_ok means unit was
+ *         executed, with the actual result stored in \p op; for asynchronous
+ *         actions, pcmk_rc_ok means action was initiated)
+ * \note It is the caller's responsibility to free the path.
+ */
+static int
+invoke_unit_by_name(const char *arg_name, svc_action_t *op, char **path)
+{
+    DBusMessage *msg;
+    DBusMessage *reply = NULL;
+    DBusPendingCall *pending = NULL;
+    char *name = NULL;
+
+    if (!systemd_init()) {
+        if (op != NULL) {
+            services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                                 "No DBus connection");
+        }
+        return ENOTCONN;
+    }
+
+    /* Create a LoadUnit DBus method (equivalent to GetUnit if already loaded),
+     * which makes the unit usable via further DBus methods.
+     *
+     * <method name="LoadUnit">
+     *  <arg name="name" type="s" direction="in"/>
+     *  <arg name="unit" type="o" direction="out"/>
+     * </method>
+     */
+    msg = systemd_new_method("LoadUnit");
+    CRM_ASSERT(msg != NULL);
+
+    // Add the (expanded) unit name as the argument
+    name = systemd_service_name(arg_name, op == NULL || pcmk__str_eq(op->action, "meta-data", pcmk__str_none));
+    CRM_LOG_ASSERT(dbus_message_append_args(msg, DBUS_TYPE_STRING, &name,
+                                            DBUS_TYPE_INVALID));
+    free(name);
+
+    if ((op == NULL) || op->synchronous) {
+        // For synchronous ops, wait for a reply and extract the result
+        const char *unit = NULL;
+        int rc = pcmk_rc_ok;
+
+        reply = systemd_send_recv(msg, NULL,
+                                  (op? op->timeout : DBUS_TIMEOUT_USE_DEFAULT));
+        dbus_message_unref(msg);
+
+        unit = execute_after_loadunit(reply, op);
+        if (unit == NULL) {
+            rc = ENOENT;
+            if (path != NULL) {
+                *path = NULL;
+            }
+        } else if (path != NULL) {
+            *path = strdup(unit);
+            if (*path == NULL) {
+                rc = ENOMEM;
+            }
+        }
+
+        if (reply != NULL) {
+            dbus_message_unref(reply);
+        }
+        return rc;
+    }
+
+    // For asynchronous ops, initiate the LoadUnit call and return
+    pending = systemd_send(msg, loadunit_completed, op, op->timeout);
+    if (pending == NULL) {
+        services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                             "Unable to send DBus message");
+        dbus_message_unref(msg);
+        return ECOMM;
+    }
+
+    // LoadUnit was successfully initiated
+    services__set_result(op, PCMK_OCF_UNKNOWN, PCMK_EXEC_PENDING, NULL);
+    services_set_op_pending(op, pending);
+    dbus_message_unref(msg);
+    return pcmk_rc_ok;
+}
+
+/*!
+ * \internal
+ * \brief Compare two strings alphabetically (case-insensitive)
+ *
+ * \param[in] a  First string to compare
+ * \param[in] b  Second string to compare
+ *
+ * \return 0 if strings are equal, -1 if a < b, 1 if a > b
+ *
+ * \note Usable as a GCompareFunc with g_list_sort().
+ *       NULL is considered less than non-NULL.
+ */
+static gint
+sort_str(gconstpointer a, gconstpointer b)
+{
+    if (!a && !b) {
+        return 0;
+    } else if (!a) {
+        return -1;
+    } else if (!b) {
+        return 1;
+    }
+    return strcasecmp(a, b);
+}
+
+GList *
+systemd_unit_listall(void)
+{
+    int nfiles = 0;
+    GList *units = NULL;
+    DBusMessageIter args;
+    DBusMessageIter unit;
+    DBusMessageIter elem;
+    DBusMessage *reply = NULL;
+
+    if (systemd_init() == FALSE) {
+        return NULL;
+    }
+
+/*
+        "  <method name=\"ListUnitFiles\">\n"                               \
+        "   <arg name=\"files\" type=\"a(ss)\" direction=\"out\"/>\n" \
+        "  </method>\n"                                                 \
+*/
+
+    reply = systemd_call_simple_method("ListUnitFiles");
+    if (reply == NULL) {
+        return NULL;
+    }
+    if (!dbus_message_iter_init(reply, &args)) {
+        crm_err("Could not list systemd unit files: systemd reply has no arguments");
+        dbus_message_unref(reply);
+        return NULL;
+    }
+    if (!pcmk_dbus_type_check(reply, &args, DBUS_TYPE_ARRAY,
+                              __func__, __LINE__)) {
+        crm_err("Could not list systemd unit files: systemd reply has invalid arguments");
+        dbus_message_unref(reply);
+        return NULL;
+    }
+
+    dbus_message_iter_recurse(&args, &unit);
+    for (; dbus_message_iter_get_arg_type(&unit) != DBUS_TYPE_INVALID;
+        dbus_message_iter_next(&unit)) {
+
+        DBusBasicValue value;
+        const char *match = NULL;
+        char *unit_name = NULL;
+        char *basename = NULL;
+
+        if(!pcmk_dbus_type_check(reply, &unit, DBUS_TYPE_STRUCT, __func__, __LINE__)) {
+            crm_warn("Skipping systemd reply argument with unexpected type");
+            continue;
+        }
+
+        dbus_message_iter_recurse(&unit, &elem);
+        if(!pcmk_dbus_type_check(reply, &elem, DBUS_TYPE_STRING, __func__, __LINE__)) {
+            crm_warn("Skipping systemd reply argument with no string");
+            continue;
+        }
+
+        dbus_message_iter_get_basic(&elem, &value);
+        if (value.str == NULL) {
+            crm_debug("ListUnitFiles reply did not provide a string");
+            continue;
+        }
+        crm_trace("DBus ListUnitFiles listed: %s", value.str);
+
+        match = systemd_unit_extension(value.str);
+        if (match == NULL) {
+            // This is not a unit file type we know how to manage
+            crm_debug("ListUnitFiles entry '%s' is not supported as resource",
+                      value.str);
+            continue;
+        }
+
+        // ListUnitFiles returns full path names, we just want base name
+        basename = strrchr(value.str, '/');
+        if (basename) {
+            basename = basename + 1;
+        } else {
+            basename = value.str;
+        }
+
+        if (!strcmp(match, ".service")) {
+            // Service is the "default" unit type, so strip it
+            unit_name = strndup(basename, match - basename);
+        } else {
+            unit_name = strdup(basename);
+        }
+
+        nfiles++;
+        units = g_list_prepend(units, unit_name);
+    }
+
+    dbus_message_unref(reply);
+
+    crm_trace("Found %d manageable systemd unit files", nfiles);
+    units = g_list_sort(units, sort_str);
+    return units;
+}
+
+gboolean
+systemd_unit_exists(const char *name)
+{
+    char *path = NULL;
+    char *state = NULL;
+
+    /* Note: Makes a blocking dbus calls
+     * Used by resources_find_service_class() when resource class=service
+     */
+    if ((invoke_unit_by_name(name, NULL, &path) != pcmk_rc_ok)
+        || (path == NULL)) {
+        return FALSE;
+    }
+
+    /* A successful LoadUnit is not sufficient to determine the unit's
+     * existence; it merely means the LoadUnit request received a reply.
+     * We must make another blocking call to check the LoadState property.
+     */
+    state = systemd_get_property(path, "LoadState", NULL, NULL, NULL,
+                                 DBUS_TIMEOUT_USE_DEFAULT);
+    free(path);
+    if (pcmk__str_any_of(state, "loaded", "masked", NULL)) {
+        free(state);
+        return TRUE;
+    }
+    free(state);
+    return FALSE;
+}
+
+#define METADATA_FORMAT                                                     \
+    "<?xml version=\"1.0\"?>\n"                                             \
+    "<!DOCTYPE resource-agent SYSTEM \"ra-api-1.dtd\">\n"                   \
+    "<resource-agent name=\"%s\" version=\"" PCMK_DEFAULT_AGENT_VERSION "\">\n" \
+    "  <version>1.1</version>\n"                                            \
+    "  <longdesc lang=\"en\">\n"                                            \
+    "    %s\n"                                                              \
+    "  </longdesc>\n"                                                       \
+    "  <shortdesc lang=\"en\">systemd unit file for %s</shortdesc>\n"       \
+    "  <parameters/>\n"                                                     \
+    "  <actions>\n"                                                         \
+    "    <action name=\"start\"     timeout=\"100\" />\n"                   \
+    "    <action name=\"stop\"      timeout=\"100\" />\n"                   \
+    "    <action name=\"status\"    timeout=\"100\" />\n"                   \
+    "    <action name=\"monitor\"   timeout=\"100\" interval=\"60\"/>\n"    \
+    "    <action name=\"meta-data\" timeout=\"5\"   />\n"                   \
+    "  </actions>\n"                                                        \
+    "  <special tag=\"systemd\"/>\n"                                        \
+    "</resource-agent>\n"
+
+static char *
+systemd_unit_metadata(const char *name, int timeout)
+{
+    char *meta = NULL;
+    char *desc = NULL;
+    char *path = NULL;
+
+    char *escaped = NULL;
+
+    if (invoke_unit_by_name(name, NULL, &path) == pcmk_rc_ok) {
+        /* TODO: Worth a making blocking call for? Probably not. Possibly if cached. */
+        desc = systemd_get_property(path, "Description", NULL, NULL, NULL,
+                                    timeout);
+    } else {
+        desc = crm_strdup_printf("Systemd unit file for %s", name);
+    }
+
+    escaped = crm_xml_escape(desc);
+
+    meta = crm_strdup_printf(METADATA_FORMAT, name, escaped, name);
+    free(desc);
+    free(path);
+    free(escaped);
+    return meta;
+}
+
+/*!
+ * \internal
+ * \brief Determine result of method from reply
+ *
+ * \param[in]     reply  Reply to start, stop, or restart request
+ * \param[in,out] op     Action that was executed
+ */
+static void
+process_unit_method_reply(DBusMessage *reply, svc_action_t *op)
+{
+    DBusError error;
+
+    /* The first use of error here is not used other than as a non-NULL flag to
+     * indicate that a request was indeed sent
+     */
+    if (pcmk_dbus_find_error((void *) &error, reply, &error)) {
+        set_result_from_method_error(op, &error);
+        dbus_error_free(&error);
+
+    } else if (!pcmk_dbus_type_check(reply, NULL, DBUS_TYPE_OBJECT_PATH,
+                                     __func__, __LINE__)) {
+        crm_info("DBus request for %s of %s succeeded but "
+                 "return type was unexpected",
+                 op->action, pcmk__s(op->rsc, "unknown resource"));
+        services__set_result(op, PCMK_OCF_OK, PCMK_EXEC_DONE,
+                             "systemd DBus method had unexpected reply");
+
+    } else {
+        const char *path = NULL;
+
+        dbus_message_get_args(reply, NULL,
+                              DBUS_TYPE_OBJECT_PATH, &path,
+                              DBUS_TYPE_INVALID);
+        crm_debug("DBus request for %s of %s using %s succeeded",
+                  op->action, pcmk__s(op->rsc, "unknown resource"), path);
+        services__set_result(op, PCMK_OCF_OK, PCMK_EXEC_DONE, NULL);
+    }
+}
+
+/*!
+ * \internal
+ * \brief Process the completion of an asynchronous unit start, stop, or restart
+ *
+ * \param[in,out] pending    If not NULL, DBus call associated with request
+ * \param[in,out] user_data  Action that was executed
+ */
+static void
+unit_method_complete(DBusPendingCall *pending, void *user_data)
+{
+    DBusMessage *reply = NULL;
+    svc_action_t *op = user_data;
+
+    crm_trace("Result for %s arrived", op->id);
+
+    // Grab the reply
+    if (pending != NULL) {
+        reply = dbus_pending_call_steal_reply(pending);
+    }
+
+    // The call is no longer pending
+    CRM_LOG_ASSERT(pending == op->opaque->pending);
+    services_set_op_pending(op, NULL);
+
+    // Determine result and finalize action
+    process_unit_method_reply(reply, op);
+    services__finalize_async_op(op);
+    if (reply != NULL) {
+        dbus_message_unref(reply);
+    }
+}
+
+#define SYSTEMD_OVERRIDE_ROOT "/run/systemd/system/"
+
+/* When the cluster manages a systemd resource, we create a unit file override
+ * to order the service "before" pacemaker. The "before" relationship won't
+ * actually be used, since systemd won't ever start the resource -- we're
+ * interested in the reverse shutdown ordering it creates, to ensure that
+ * systemd doesn't stop the resource at shutdown while pacemaker is still
+ * running.
+ *
+ * @TODO Add start timeout
+ */
+#define SYSTEMD_OVERRIDE_TEMPLATE                           \
+    "[Unit]\n"                                              \
+    "Description=Cluster Controlled %s\n"                   \
+    "Before=pacemaker.service pacemaker_remote.service\n"   \
+    "\n"                                                    \
+    "[Service]\n"                                           \
+    "Restart=no\n"
+
+// Temporarily use rwxr-xr-x umask when opening a file for writing
+static FILE *
+create_world_readable(const char *filename)
+{
+    mode_t orig_umask = umask(S_IWGRP | S_IWOTH);
+    FILE *fp = fopen(filename, "w");
+
+    umask(orig_umask);
+    return fp;
+}
+
+static void
+create_override_dir(const char *agent)
+{
+    char *override_dir = crm_strdup_printf(SYSTEMD_OVERRIDE_ROOT
+                                           "/%s.service.d", agent);
+    int rc = pcmk__build_path(override_dir, 0755);
+
+    if (rc != pcmk_rc_ok) {
+        crm_warn("Could not create systemd override directory %s: %s",
+                 override_dir, pcmk_rc_str(rc));
+    }
+    free(override_dir);
+}
+
+static char *
+get_override_filename(const char *agent)
+{
+    return crm_strdup_printf(SYSTEMD_OVERRIDE_ROOT
+                             "/%s.service.d/50-pacemaker.conf", agent);
+}
+
+static void
+systemd_create_override(const char *agent, int timeout)
+{
+    FILE *file_strm = NULL;
+    char *override_file = get_override_filename(agent);
+
+    create_override_dir(agent);
+
+    /* Ensure the override file is world-readable. This is not strictly
+     * necessary, but it avoids a systemd warning in the logs.
+     */
+    file_strm = create_world_readable(override_file);
+    if (file_strm == NULL) {
+        crm_err("Cannot open systemd override file %s for writing",
+                override_file);
+    } else {
+        char *override = crm_strdup_printf(SYSTEMD_OVERRIDE_TEMPLATE, agent);
+
+        int rc = fprintf(file_strm, "%s\n", override);
+
+        free(override);
+        if (rc < 0) {
+            crm_perror(LOG_WARNING, "Cannot write to systemd override file %s",
+                       override_file);
+        }
+        fflush(file_strm);
+        fclose(file_strm);
+        systemd_daemon_reload(timeout);
+    }
+
+    free(override_file);
+}
+
+static void
+systemd_remove_override(const char *agent, int timeout)
+{
+    char *override_file = get_override_filename(agent);
+    int rc = unlink(override_file);
+
+    if (rc < 0) {
+        // Stop may be called when already stopped, which is fine
+        crm_perror(LOG_DEBUG, "Cannot remove systemd override file %s",
+                   override_file);
+    } else {
+        systemd_daemon_reload(timeout);
+    }
+    free(override_file);
+}
+
+/*!
+ * \internal
+ * \brief Parse result of systemd status check
+ *
+ * Set a status action's exit status and execution status based on a DBus
+ * property check result, and finalize the action if asynchronous.
+ *
+ * \param[in]     name      DBus interface name for property that was checked
+ * \param[in]     state     Property value
+ * \param[in,out] userdata  Status action that check was done for
+ */
+static void
+parse_status_result(const char *name, const char *state, void *userdata)
+{
+    svc_action_t *op = userdata;
+
+    crm_trace("Resource %s has %s='%s'",
+              pcmk__s(op->rsc, "(unspecified)"), name,
+              pcmk__s(state, "<null>"));
+
+    if (pcmk__str_eq(state, "active", pcmk__str_none)) {
+        services__set_result(op, PCMK_OCF_OK, PCMK_EXEC_DONE, NULL);
+
+    } else if (pcmk__str_eq(state, "reloading", pcmk__str_none)) {
+        services__set_result(op, PCMK_OCF_OK, PCMK_EXEC_DONE, NULL);
+
+    } else if (pcmk__str_eq(state, "activating", pcmk__str_none)) {
+        services__set_result(op, PCMK_OCF_UNKNOWN, PCMK_EXEC_PENDING, NULL);
+
+    } else if (pcmk__str_eq(state, "deactivating", pcmk__str_none)) {
+        services__set_result(op, PCMK_OCF_UNKNOWN, PCMK_EXEC_PENDING, NULL);
+
+    } else {
+        services__set_result(op, PCMK_OCF_NOT_RUNNING, PCMK_EXEC_DONE, state);
+    }
+
+    if (!(op->synchronous)) {
+        services_set_op_pending(op, NULL);
+        services__finalize_async_op(op);
+    }
+}
+
+/*!
+ * \internal
+ * \brief Invoke a systemd unit, given its DBus object path
+ *
+ * \param[in,out] op    Action to execute
+ * \param[in]     unit  DBus object path of systemd unit to invoke
+ */
+static void
+invoke_unit_by_path(svc_action_t *op, const char *unit)
+{
+    const char *method = NULL;
+    DBusMessage *msg = NULL;
+    DBusMessage *reply = NULL;
+
+    if (pcmk__str_any_of(op->action, "monitor", "status", NULL)) {
+        DBusPendingCall *pending = NULL;
+        char *state;
+
+        state = systemd_get_property(unit, "ActiveState",
+                                     (op->synchronous? NULL : parse_status_result),
+                                     op, (op->synchronous? NULL : &pending),
+                                     op->timeout);
+        if (op->synchronous) {
+            parse_status_result("ActiveState", state, op);
+            free(state);
+
+        } else if (pending == NULL) { // Could not get ActiveState property
+            services__format_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                                    "Could not get state for unit %s from DBus",
+                                    op->agent);
+            services__finalize_async_op(op);
+
+        } else {
+            services_set_op_pending(op, pending);
+        }
+        return;
+
+    } else if (pcmk__str_eq(op->action, "start", pcmk__str_none)) {
+        method = "StartUnit";
+        systemd_create_override(op->agent, op->timeout);
+
+    } else if (pcmk__str_eq(op->action, "stop", pcmk__str_none)) {
+        method = "StopUnit";
+        systemd_remove_override(op->agent, op->timeout);
+
+    } else if (pcmk__str_eq(op->action, "restart", pcmk__str_none)) {
+        method = "RestartUnit";
+
+    } else {
+        services__format_result(op, PCMK_OCF_UNIMPLEMENT_FEATURE,
+                                PCMK_EXEC_ERROR,
+                                "Action %s not implemented "
+                                "for systemd resources",
+                                pcmk__s(op->action, "(unspecified)"));
+        if (!(op->synchronous)) {
+            services__finalize_async_op(op);
+        }
+        return;
+    }
+
+    crm_trace("Calling %s for unit path %s%s%s",
+              method, unit,
+              ((op->rsc == NULL)? "" : " for resource "), pcmk__s(op->rsc, ""));
+
+    msg = systemd_new_method(method);
+    CRM_ASSERT(msg != NULL);
+
+    /* (ss) */
+    {
+        const char *replace_s = "replace";
+        char *name = systemd_service_name(op->agent, pcmk__str_eq(op->action, "meta-data", pcmk__str_none));
+
+        CRM_LOG_ASSERT(dbus_message_append_args(msg, DBUS_TYPE_STRING, &name, DBUS_TYPE_INVALID));
+        CRM_LOG_ASSERT(dbus_message_append_args(msg, DBUS_TYPE_STRING, &replace_s, DBUS_TYPE_INVALID));
+
+        free(name);
+    }
+
+    if (op->synchronous) {
+        reply = systemd_send_recv(msg, NULL, op->timeout);
+        dbus_message_unref(msg);
+        process_unit_method_reply(reply, op);
+        if (reply != NULL) {
+            dbus_message_unref(reply);
+        }
+
+    } else {
+        DBusPendingCall *pending = systemd_send(msg, unit_method_complete, op,
+                                                op->timeout);
+
+        dbus_message_unref(msg);
+        if (pending == NULL) {
+            services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                                 "Unable to send DBus message");
+            services__finalize_async_op(op);
+
+        } else {
+            services_set_op_pending(op, pending);
+        }
+    }
+}
+
+static gboolean
+systemd_timeout_callback(gpointer p)
+{
+    svc_action_t * op = p;
+
+    op->opaque->timerid = 0;
+    crm_info("%s action for systemd unit %s named '%s' timed out",
+             op->action, op->agent, op->rsc);
+    services__format_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_TIMEOUT,
+                            "%s action for systemd unit %s "
+                            "did not complete in time", op->action, op->agent);
+    services__finalize_async_op(op);
+    return FALSE;
+}
+
+/*!
+ * \internal
+ * \brief Execute a systemd action
+ *
+ * \param[in,out] op  Action to execute
+ *
+ * \return Standard Pacemaker return code
+ * \retval EBUSY          Recurring operation could not be initiated
+ * \retval pcmk_rc_error  Synchronous action failed
+ * \retval pcmk_rc_ok     Synchronous action succeeded, or asynchronous action
+ *                        should not be freed (because it's pending or because
+ *                        it failed to execute and was already freed)
+ *
+ * \note If the return value for an asynchronous action is not pcmk_rc_ok, the
+ *       caller is responsible for freeing the action.
+ */
+int
+services__execute_systemd(svc_action_t *op)
+{
+    CRM_ASSERT(op != NULL);
+
+    if ((op->action == NULL) || (op->agent == NULL)) {
+        services__set_result(op, PCMK_OCF_NOT_CONFIGURED, PCMK_EXEC_ERROR_FATAL,
+                             "Bug in action caller");
+        goto done;
+    }
+
+    if (!systemd_init()) {
+        services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                             "No DBus connection");
+        goto done;
+    }
+
+    crm_debug("Performing %ssynchronous %s op on systemd unit %s%s%s",
+              (op->synchronous? "" : "a"), op->action, op->agent,
+              ((op->rsc == NULL)? "" : " for resource "), pcmk__s(op->rsc, ""));
+
+    if (pcmk__str_eq(op->action, "meta-data", pcmk__str_casei)) {
+        op->stdout_data = systemd_unit_metadata(op->agent, op->timeout);
+        services__set_result(op, PCMK_OCF_OK, PCMK_EXEC_DONE, NULL);
+        goto done;
+    }
+
+    /* invoke_unit_by_name() should always override these values, which are here
+     * just as a fail-safe in case there are any code paths that neglect to
+     */
+    services__set_result(op, PCMK_OCF_UNKNOWN_ERROR, PCMK_EXEC_ERROR,
+                         "Bug in service library");
+
+    if (invoke_unit_by_name(op->agent, op, NULL) == pcmk_rc_ok) {
+        op->opaque->timerid = g_timeout_add(op->timeout + 5000,
+                                            systemd_timeout_callback, op);
+        services_add_inflight_op(op);
+        return pcmk_rc_ok;
+    }
+
+done:
+    if (op->synchronous) {
+        return (op->rc == PCMK_OCF_OK)? pcmk_rc_ok : pcmk_rc_error;
+    } else {
+        return services__finalize_async_op(op);
+    }
+}