shared: add generic logic for waiting for a unit to enter some state
This is a generic implementation of a client-side logic of waiting until a unit enters or leaves some state. This is a more generic implementation of the WaitContext logic currently in systemctl.c, and is supposed to replace it (a later commit does this). It's similar to bus-wait-for-jobs.c and we probably should fold that one into it later on. This code is more powerful and cleaner than the WaitContext logic however. In addition to waiting for a unit to exit this also allows us to wait for a unit to leave the "maintainance" state. This commit only implements the generic logic, and adds no users of it yet.
This commit is contained in:
Lennart Poettering
parent
345f322185
commit
3572d3df8f
434
src/shared/bus-wait-for-units.c
Normal file
434
src/shared/bus-wait-for-units.c
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@ -0,0 +1,434 @@
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/* SPDX-License-Identifier: LGPL-2.1+ */
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#include "bus-util.h"
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#include "bus-wait-for-units.h"
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#include "hashmap.h"
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#include "string-util.h"
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#include "strv.h"
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#include "unit-def.h"
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typedef struct WaitForItem {
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BusWaitForUnits *parent;
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BusWaitForUnitsFlags flags;
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char *bus_path;
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sd_bus_slot *slot_get_all;
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sd_bus_slot *slot_properties_changed;
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bus_wait_for_units_unit_callback unit_callback;
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void *userdata;
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char *active_state;
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uint32_t job_id;
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char *clean_result;
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} WaitForItem;
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typedef struct BusWaitForUnits {
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sd_bus *bus;
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sd_bus_slot *slot_disconnected;
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Hashmap *items;
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bus_wait_for_units_ready_callback ready_callback;
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void *userdata;
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WaitForItem *current;
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BusWaitForUnitsState state;
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bool has_failed:1;
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} BusWaitForUnits;
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static WaitForItem *wait_for_item_free(WaitForItem *item) {
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int r;
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if (!item)
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return NULL;
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if (item->parent) {
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if (FLAGS_SET(item->flags, BUS_WAIT_REFFED) && item->bus_path && item->parent->bus) {
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r = sd_bus_call_method_async(
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item->parent->bus,
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NULL,
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"org.freedesktop.systemd1",
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item->bus_path,
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"org.freedesktop.systemd1.Unit",
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"Unref",
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NULL,
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NULL,
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NULL);
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if (r < 0)
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log_debug_errno(r, "Failed to drop reference to unit %s, ignoring: %m", item->bus_path);
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}
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assert_se(hashmap_remove(item->parent->items, item->bus_path) == item);
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if (item->parent->current == item)
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item->parent->current = NULL;
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}
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sd_bus_slot_unref(item->slot_properties_changed);
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sd_bus_slot_unref(item->slot_get_all);
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free(item->bus_path);
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free(item->active_state);
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free(item->clean_result);
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return mfree(item);
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}
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DEFINE_TRIVIAL_CLEANUP_FUNC(WaitForItem*, wait_for_item_free);
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static void bus_wait_for_units_clear(BusWaitForUnits *d) {
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WaitForItem *item;
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assert(d);
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d->slot_disconnected = sd_bus_slot_unref(d->slot_disconnected);
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d->bus = sd_bus_unref(d->bus);
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while ((item = hashmap_first(d->items))) {
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d->current = item;
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item->unit_callback(d, item->bus_path, false, item->userdata);
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wait_for_item_free(item);
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}
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d->items = hashmap_free(d->items);
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}
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static int match_disconnected(sd_bus_message *m, void *userdata, sd_bus_error *error) {
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BusWaitForUnits *d = userdata;
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assert(m);
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assert(d);
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log_error("Warning! D-Bus connection terminated.");
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bus_wait_for_units_clear(d);
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if (d->ready_callback)
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d->ready_callback(d, false, d->userdata);
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else /* If no ready callback is specified close the connection so that the event loop exits */
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sd_bus_close(sd_bus_message_get_bus(m));
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return 0;
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}
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int bus_wait_for_units_new(sd_bus *bus, BusWaitForUnits **ret) {
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_cleanup_(bus_wait_for_units_freep) BusWaitForUnits *d = NULL;
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int r;
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assert(bus);
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assert(ret);
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d = new(BusWaitForUnits, 1);
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if (!d)
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return -ENOMEM;
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*d = (BusWaitForUnits) {
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.state = BUS_WAIT_SUCCESS,
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.bus = sd_bus_ref(bus),
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};
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r = sd_bus_match_signal_async(
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bus,
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&d->slot_disconnected,
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"org.freedesktop.DBus.Local",
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NULL,
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"org.freedesktop.DBus.Local",
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"Disconnected",
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match_disconnected, NULL, d);
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if (r < 0)
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return r;
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*ret = TAKE_PTR(d);
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return 0;
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}
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BusWaitForUnits* bus_wait_for_units_free(BusWaitForUnits *d) {
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if (!d)
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return NULL;
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bus_wait_for_units_clear(d);
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sd_bus_slot_unref(d->slot_disconnected);
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sd_bus_unref(d->bus);
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return mfree(d);
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}
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static bool bus_wait_for_units_is_ready(BusWaitForUnits *d) {
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assert(d);
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if (!d->bus) /* Disconnected? */
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return true;
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return hashmap_isempty(d->items);
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}
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void bus_wait_for_units_set_ready_callback(BusWaitForUnits *d, bus_wait_for_units_ready_callback callback, void *userdata) {
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assert(d);
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d->ready_callback = callback;
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d->userdata = userdata;
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}
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static void bus_wait_for_units_check_ready(BusWaitForUnits *d) {
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assert(d);
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if (!bus_wait_for_units_is_ready(d))
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return;
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d->state = d->has_failed ? BUS_WAIT_FAILURE : BUS_WAIT_SUCCESS;
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if (d->ready_callback)
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d->ready_callback(d, d->state, d->userdata);
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}
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static void wait_for_item_check_ready(WaitForItem *item) {
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BusWaitForUnits *d;
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assert(item);
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assert(d = item->parent);
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if (FLAGS_SET(item->flags, BUS_WAIT_FOR_MAINTENANCE_END)) {
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if (item->clean_result && !streq(item->clean_result, "success"))
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d->has_failed = true;
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if (!item->active_state || streq(item->active_state, "maintenance"))
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return;
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}
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if (FLAGS_SET(item->flags, BUS_WAIT_NO_JOB) && item->job_id != 0)
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return;
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if (FLAGS_SET(item->flags, BUS_WAIT_FOR_INACTIVE)) {
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if (streq_ptr(item->active_state, "failed"))
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d->has_failed = true;
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else if (!streq_ptr(item->active_state, "inactive"))
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return;
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}
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if (item->unit_callback) {
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d->current = item;
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item->unit_callback(d, item->bus_path, true, item->userdata);
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}
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wait_for_item_free(item);
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bus_wait_for_units_check_ready(d);
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}
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static int property_map_job(
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sd_bus *bus,
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const char *member,
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sd_bus_message *m,
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sd_bus_error *error,
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void *userdata) {
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WaitForItem *item = userdata;
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const char *path;
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uint32_t id;
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int r;
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assert(item);
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r = sd_bus_message_read(m, "(uo)", &id, &path);
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if (r < 0)
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return r;
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item->job_id = id;
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return 0;
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}
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static int wait_for_item_parse_properties(WaitForItem *item, sd_bus_message *m) {
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static const struct bus_properties_map map[] = {
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{ "ActiveState", "s", NULL, offsetof(WaitForItem, active_state) },
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{ "Job", "(uo)", property_map_job, 0 },
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{ "CleanResult", "s", NULL, offsetof(WaitForItem, clean_result) },
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{}
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};
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int r;
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assert(item);
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assert(m);
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r = bus_message_map_all_properties(m, map, BUS_MAP_STRDUP, NULL, item);
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if (r < 0)
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return r;
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wait_for_item_check_ready(item);
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return 0;
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}
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static int on_properties_changed(sd_bus_message *m, void *userdata, sd_bus_error *error) {
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WaitForItem *item = userdata;
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const char *interface;
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int r;
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assert(item);
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r = sd_bus_message_read(m, "s", &interface);
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if (r < 0) {
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log_debug_errno(r, "Failed to parse PropertiesChanged signal: %m");
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return 0;
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}
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if (!streq(interface, "org.freedesktop.systemd1.Unit"))
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return 0;
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r = wait_for_item_parse_properties(item, m);
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if (r < 0)
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log_debug_errno(r, "Failed to process PropertiesChanged signal: %m");
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return 0;
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}
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static int on_get_all_properties(sd_bus_message *m, void *userdata, sd_bus_error *error) {
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WaitForItem *item = userdata;
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int r;
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assert(item);
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if (sd_bus_error_is_set(error)) {
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BusWaitForUnits *d = item->parent;
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d->has_failed = true;
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log_debug_errno(sd_bus_error_get_errno(error), "GetAll() failed for %s: %s",
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item->bus_path, error->message);
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d->current = item;
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item->unit_callback(d, item->bus_path, false, item->userdata);
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wait_for_item_free(item);
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bus_wait_for_units_check_ready(d);
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return 0;
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}
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r = wait_for_item_parse_properties(item, m);
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if (r < 0)
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log_debug_errno(r, "Failed to process GetAll method reply: %m");
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return 0;
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}
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int bus_wait_for_units_add_unit(
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BusWaitForUnits *d,
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const char *unit,
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BusWaitForUnitsFlags flags,
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bus_wait_for_units_unit_callback callback,
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void *userdata) {
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_cleanup_(wait_for_item_freep) WaitForItem *item = NULL;
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int r;
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assert(d);
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assert(unit);
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assert(flags != 0);
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r = hashmap_ensure_allocated(&d->items, &string_hash_ops);
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if (r < 0)
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return r;
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item = new(WaitForItem, 1);
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if (!item)
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return -ENOMEM;
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*item = (WaitForItem) {
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.flags = flags,
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.bus_path = unit_dbus_path_from_name(unit),
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.unit_callback = callback,
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.userdata = userdata,
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.job_id = UINT32_MAX,
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};
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if (!item->bus_path)
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return -ENOMEM;
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if (!FLAGS_SET(item->flags, BUS_WAIT_REFFED)) {
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r = sd_bus_call_method_async(
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d->bus,
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NULL,
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"org.freedesktop.systemd1",
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item->bus_path,
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"org.freedesktop.systemd1.Unit",
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"Ref",
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NULL,
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NULL,
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NULL);
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if (r < 0)
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return log_debug_errno(r, "Failed to add reference to unit %s: %m", unit);
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item->flags |= BUS_WAIT_REFFED;
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}
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r = sd_bus_match_signal_async(
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d->bus,
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&item->slot_properties_changed,
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"org.freedesktop.systemd1",
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item->bus_path,
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"org.freedesktop.DBus.Properties",
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"PropertiesChanged",
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on_properties_changed,
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NULL,
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item);
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if (r < 0)
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return log_debug_errno(r, "Failed to request match for PropertiesChanged signal: %m");
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r = sd_bus_call_method_async(
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d->bus,
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&item->slot_get_all,
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"org.freedesktop.systemd1",
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item->bus_path,
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"org.freedesktop.DBus.Properties",
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"GetAll",
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on_get_all_properties,
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item,
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"s", FLAGS_SET(item->flags, BUS_WAIT_FOR_MAINTENANCE_END) ? NULL : "org.freedesktop.systemd1.Unit");
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if (r < 0)
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return log_debug_errno(r, "Failed to request properties of unit %s: %m", unit);
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r = hashmap_put(d->items, item->bus_path, item);
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if (r < 0)
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return r;
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d->state = BUS_WAIT_RUNNING;
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item->parent = d;
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TAKE_PTR(item);
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return 0;
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}
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int bus_wait_for_units_run(BusWaitForUnits *d) {
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int r;
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assert(d);
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while (d->state == BUS_WAIT_RUNNING) {
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r = sd_bus_process(d->bus, NULL);
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if (r < 0)
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return r;
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if (r > 0)
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continue;
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r = sd_bus_wait(d->bus, (uint64_t) -1);
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if (r < 0)
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return r;
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}
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return d->state;
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}
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BusWaitForUnitsState bus_wait_for_units_state(BusWaitForUnits *d) {
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assert(d);
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return d->state;
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}
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35
src/shared/bus-wait-for-units.h
Normal file
35
src/shared/bus-wait-for-units.h
Normal file
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@ -0,0 +1,35 @@
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/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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#include "macro.h"
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#include "sd-bus.h"
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typedef struct BusWaitForUnits BusWaitForUnits;
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typedef enum BusWaitForUnitsState {
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BUS_WAIT_SUCCESS, /* Nothing to wait for anymore and nothing failed */
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BUS_WAIT_FAILURE, /* dito, but something failed */
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BUS_WAIT_RUNNING, /* Still something to wait for */
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_BUS_WAIT_FOR_UNITS_STATE_MAX,
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_BUS_WAIT_FOR_UNITS_STATE_INVALID = -1,
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} BusWaitForUnitsState;
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typedef enum BusWaitForUnitsFlags {
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BUS_WAIT_FOR_MAINTENANCE_END = 1 << 0, /* Wait until the unit is no longer in maintenance state */
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BUS_WAIT_FOR_INACTIVE = 1 << 1, /* Wait until the unit is back in inactive or dead state */
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BUS_WAIT_NO_JOB = 1 << 2, /* Wait until there's no more job pending */
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BUS_WAIT_REFFED = 1 << 3, /* The unit is already reffed with RefUnit() */
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} BusWaitForUnitsFlags;
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typedef void (*bus_wait_for_units_ready_callback)(BusWaitForUnits *d, BusWaitForUnitsState state, void *userdata);
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typedef void (*bus_wait_for_units_unit_callback)(BusWaitForUnits *d, const char *unit_path, bool good, void *userdata);
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int bus_wait_for_units_new(sd_bus *bus, BusWaitForUnits **ret);
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BusWaitForUnits* bus_wait_for_units_free(BusWaitForUnits *d);
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BusWaitForUnitsState bus_wait_for_units_state(BusWaitForUnits *d);
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void bus_wait_for_units_set_ready_callback(BusWaitForUnits *d, bus_wait_for_units_ready_callback callback, void *userdata);
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int bus_wait_for_units_add_unit(BusWaitForUnits *d, const char *unit, BusWaitForUnitsFlags flags, bus_wait_for_units_unit_callback callback, void *userdata);
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int bus_wait_for_units_run(BusWaitForUnits *d);
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DEFINE_TRIVIAL_CLEANUP_FUNC(BusWaitForUnits*, bus_wait_for_units_free);
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@ -29,6 +29,8 @@ shared_sources = files('''
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bus-util.h
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bus-wait-for-jobs.c
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bus-wait-for-jobs.h
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bus-wait-for-units.c
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bus-wait-for-units.h
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calendarspec.c
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calendarspec.h
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cgroup-show.c
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