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-rw-r--r--src/event_hdl.c999
1 files changed, 999 insertions, 0 deletions
diff --git a/src/event_hdl.c b/src/event_hdl.c
new file mode 100644
index 0000000..aeb4d24
--- /dev/null
+++ b/src/event_hdl.c
@@ -0,0 +1,999 @@
+/*
+ * general purpose event handlers management
+ *
+ * Copyright 2022 HAProxy Technologies
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2.1 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <string.h>
+#include <haproxy/event_hdl.h>
+#include <haproxy/compiler.h>
+#include <haproxy/task.h>
+#include <haproxy/tools.h>
+#include <haproxy/errors.h>
+#include <haproxy/signal.h>
+#include <haproxy/xxhash.h>
+#include <haproxy/cfgparse.h>
+
+/* event types changes in event_hdl-t.h file should be reflected in the
+ * map below to allow string to type and type to string conversions
+ */
+static struct event_hdl_sub_type_map event_hdl_sub_type_map[] = {
+ {"NONE", EVENT_HDL_SUB_NONE},
+ {"SERVER", EVENT_HDL_SUB_SERVER},
+ {"SERVER_ADD", EVENT_HDL_SUB_SERVER_ADD},
+ {"SERVER_DEL", EVENT_HDL_SUB_SERVER_DEL},
+ {"SERVER_UP", EVENT_HDL_SUB_SERVER_UP},
+ {"SERVER_DOWN", EVENT_HDL_SUB_SERVER_DOWN},
+ {"SERVER_STATE", EVENT_HDL_SUB_SERVER_STATE},
+ {"SERVER_ADMIN", EVENT_HDL_SUB_SERVER_ADMIN},
+ {"SERVER_CHECK", EVENT_HDL_SUB_SERVER_CHECK},
+ {"SERVER_INETADDR", EVENT_HDL_SUB_SERVER_INETADDR},
+};
+
+/* internal types (only used in this file) */
+struct event_hdl_async_task_default_ctx
+{
+ event_hdl_async_equeue e_queue; /* event queue list */
+ event_hdl_cb_async func; /* event handling func */
+};
+
+/* memory pools declarations */
+DECLARE_STATIC_POOL(pool_head_sub, "ehdl_sub", sizeof(struct event_hdl_sub));
+DECLARE_STATIC_POOL(pool_head_sub_event, "ehdl_sub_e", sizeof(struct event_hdl_async_event));
+DECLARE_STATIC_POOL(pool_head_sub_event_data, "ehdl_sub_ed", sizeof(struct event_hdl_async_event_data));
+DECLARE_STATIC_POOL(pool_head_sub_taskctx, "ehdl_sub_tctx", sizeof(struct event_hdl_async_task_default_ctx));
+
+/* global event_hdl tunables (public variable) */
+struct event_hdl_tune event_hdl_tune;
+
+/* global subscription list (implicit where NULL is used as sublist argument) */
+static event_hdl_sub_list global_event_hdl_sub_list;
+
+/* every known subscription lists are tracked in this list (including the global one) */
+static struct mt_list known_event_hdl_sub_list = MT_LIST_HEAD_INIT(known_event_hdl_sub_list);
+
+static void _event_hdl_sub_list_destroy(event_hdl_sub_list *sub_list);
+
+static void event_hdl_deinit(struct sig_handler *sh)
+{
+ event_hdl_sub_list *cur_list;
+ struct mt_list *elt1, elt2;
+
+ /* destroy all known subscription lists */
+ mt_list_for_each_entry_safe(cur_list, &known_event_hdl_sub_list, known, elt1, elt2) {
+ /* remove cur elem from list */
+ MT_LIST_DELETE_SAFE(elt1);
+ /* then destroy it */
+ _event_hdl_sub_list_destroy(cur_list);
+ }
+}
+
+static void event_hdl_init(void)
+{
+ /* initialize global subscription list */
+ event_hdl_sub_list_init(&global_event_hdl_sub_list);
+ /* register the deinit function, will be called on soft-stop */
+ signal_register_fct(0, event_hdl_deinit, 0);
+
+ /* set some default values */
+ event_hdl_tune.max_events_at_once = EVENT_HDL_MAX_AT_ONCE;
+}
+
+/* general purpose hashing function when you want to compute
+ * an ID based on <scope> x <name>
+ * It is your responsibility to make sure <scope> is not used
+ * elsewhere in the code (or that you are fine with sharing
+ * the scope).
+ */
+inline uint64_t event_hdl_id(const char *scope, const char *name)
+{
+ XXH64_state_t state;
+
+ XXH64_reset(&state, 0);
+ XXH64_update(&state, scope, strlen(scope));
+ XXH64_update(&state, name, strlen(name));
+ return XXH64_digest(&state);
+}
+
+/* takes a sub_type as input, returns corresponding sub_type
+ * printable string or "N/A" if not found.
+ * If not found, an error will be reported to stderr so the developers
+ * know that a sub_type is missing its associated string in event_hdl-t.h
+ */
+const char *event_hdl_sub_type_to_string(struct event_hdl_sub_type sub_type)
+{
+ int it;
+
+ for (it = 0; it < (int)(sizeof(event_hdl_sub_type_map) / sizeof(event_hdl_sub_type_map[0])); it++) {
+ if (sub_type.family == event_hdl_sub_type_map[it].type.family &&
+ sub_type.subtype == event_hdl_sub_type_map[it].type.subtype)
+ return event_hdl_sub_type_map[it].name;
+ }
+ ha_alert("event_hdl-t.h: missing sub_type string representation.\n"
+ "Please reflect any changes in event_hdl_sub_type_map.\n");
+ return "N/A";
+}
+
+/* returns the internal sub_type corresponding
+ * to the printable representation <name>
+ * or EVENT_HDL_SUB_NONE if no such event exists
+ * (see event_hdl-t.h for the complete list of supported types)
+ */
+struct event_hdl_sub_type event_hdl_string_to_sub_type(const char *name)
+{
+ int it;
+
+ for (it = 0; it < (int)(sizeof(event_hdl_sub_type_map) / sizeof(event_hdl_sub_type_map[0])); it++) {
+ if (!strcmp(name, event_hdl_sub_type_map[it].name))
+ return event_hdl_sub_type_map[it].type;
+ }
+ return EVENT_HDL_SUB_NONE;
+}
+
+/* Takes <subscriptions> sub list as input, returns a printable string
+ * containing every sub_types contained in <subscriptions>
+ * separated by '|' char.
+ * Returns NULL if no sub_types are found in <subscriptions>
+ * This functions leverages memprintf, thus it is up to the
+ * caller to free the returned value (if != NULL) when he no longer
+ * uses it.
+ */
+char *event_hdl_sub_type_print(struct event_hdl_sub_type subscriptions)
+{
+ char *out = NULL;
+ int it;
+ uint8_t first = 1;
+
+ for (it = 0; it < (int)(sizeof(event_hdl_sub_type_map) / sizeof(event_hdl_sub_type_map[0])); it++) {
+ if (subscriptions.family == event_hdl_sub_type_map[it].type.family &&
+ ((subscriptions.subtype & event_hdl_sub_type_map[it].type.subtype) ==
+ event_hdl_sub_type_map[it].type.subtype)) {
+ if (first) {
+ memprintf(&out, "%s", event_hdl_sub_type_map[it].name);
+ first--;
+ }
+ else
+ memprintf(&out, "%s%s%s", out, "|", event_hdl_sub_type_map[it].name);
+ }
+ }
+
+ return out;
+}
+
+/* event_hdl debug/reporting function */
+typedef void (*event_hdl_report_hdl_state_func)(const char *fmt, ...);
+static void event_hdl_report_hdl_state(event_hdl_report_hdl_state_func report_func,
+ const struct event_hdl *hdl, const char *what, const char *state)
+{
+ report_func("[event_hdl]:%s (%s)'#%llu@%s': %s\n",
+ what,
+ (hdl->async) ? "ASYNC" : "SYNC",
+ (long long unsigned int)hdl->id,
+ hdl->dorigin,
+ state);
+}
+
+static inline void _event_hdl_async_data_drop(struct event_hdl_async_event_data *data)
+{
+ if (HA_ATOMIC_SUB_FETCH(&data->refcount, 1) == 0) {
+ /* we were the last one holding a reference to event data - free required */
+ if (data->mfree) {
+ /* Some event data members are dynamically allocated and thus
+ * require specific cleanup using user-provided function.
+ * We directly pass a pointer to internal data storage but
+ * we only expect the cleanup function to typecast it in the
+ * relevant data type to give enough context to the function to
+ * perform the cleanup on data members, and not actually freeing
+ * data pointer since it is our internal buffer :)
+ */
+ data->mfree(&data->data);
+ }
+ pool_free(pool_head_sub_event_data, data);
+ }
+}
+
+void event_hdl_async_free_event(struct event_hdl_async_event *e)
+{
+ if (unlikely(event_hdl_sub_type_equal(e->type, EVENT_HDL_SUB_END))) {
+ /* last event for hdl, special case */
+ /* free subscription entry as we're the last one still using it
+ * (it is already removed from mt_list, no race can occur)
+ */
+ event_hdl_drop(e->sub_mgmt.this);
+ HA_ATOMIC_DEC(&jobs);
+ }
+ else if (e->_data)
+ _event_hdl_async_data_drop(e->_data); /* data wrapper */
+ pool_free(pool_head_sub_event, e);
+}
+
+/* wakeup the task depending on its type:
+ * normal async mode internally uses tasklets but advanced async mode
+ * allows both tasks and tasklets.
+ * While tasks and tasklets may be easily casted, we need to use the proper
+ * API to wake them up (the waiting queues are exclusive).
+ */
+static void event_hdl_task_wakeup(struct tasklet *task)
+{
+ if (TASK_IS_TASKLET(task))
+ tasklet_wakeup(task);
+ else
+ task_wakeup((struct task *)task, TASK_WOKEN_OTHER); /* TODO: switch to TASK_WOKEN_EVENT? */
+}
+
+/* task handler used for normal async subscription mode
+ * if you use advanced async subscription mode, you can use this
+ * as an example to implement your own task wrapper
+ */
+static struct task *event_hdl_async_task_default(struct task *task, void *ctx, unsigned int state)
+{
+ struct tasklet *tl = (struct tasklet *)task;
+ struct event_hdl_async_task_default_ctx *task_ctx = ctx;
+ struct event_hdl_async_event *event;
+ int max_notif_at_once_it = 0;
+ uint8_t done = 0;
+
+ /* run through e_queue, and call func() for each event
+ * if we read END event, it indicates we must stop:
+ * no more events to come (handler is unregistered)
+ * so we must free task_ctx and stop task
+ */
+ while (max_notif_at_once_it < event_hdl_tune.max_events_at_once &&
+ (event = event_hdl_async_equeue_pop(&task_ctx->e_queue)))
+ {
+ if (event_hdl_sub_type_equal(event->type, EVENT_HDL_SUB_END)) {
+ done = 1;
+ event_hdl_async_free_event(event);
+ /* break is normally not even required, EVENT_HDL_SUB_END
+ * is guaranteed to be last event of e_queue
+ * (because in normal mode one sub == one e_queue)
+ */
+ break;
+ }
+ else {
+ struct event_hdl_cb cb;
+
+ cb.e_type = event->type;
+ cb.e_data = event->data;
+ cb.sub_mgmt = &event->sub_mgmt;
+ cb._sync = 0;
+
+ /* call user function */
+ task_ctx->func(&cb, event->private);
+ max_notif_at_once_it++;
+ }
+ event_hdl_async_free_event(event);
+ }
+
+ if (done) {
+ /* our job is done, subscription is over: no more events to come */
+ pool_free(pool_head_sub_taskctx, task_ctx);
+ tasklet_free(tl);
+ return NULL;
+ }
+ return task;
+}
+
+/* internal subscription mgmt functions */
+static inline struct event_hdl_sub_type _event_hdl_getsub(struct event_hdl_sub *cur_sub)
+{
+ return cur_sub->sub;
+}
+
+static inline struct event_hdl_sub_type _event_hdl_getsub_async(struct event_hdl_sub *cur_sub)
+{
+ struct mt_list lock;
+ struct event_hdl_sub_type type = EVENT_HDL_SUB_NONE;
+
+ lock = MT_LIST_LOCK_ELT(&cur_sub->mt_list);
+ if (lock.next != &cur_sub->mt_list)
+ type = _event_hdl_getsub(cur_sub);
+ // else already removed
+ MT_LIST_UNLOCK_ELT(&cur_sub->mt_list, lock);
+ return type;
+}
+
+static inline int _event_hdl_resub(struct event_hdl_sub *cur_sub, struct event_hdl_sub_type type)
+{
+ if (!event_hdl_sub_family_equal(cur_sub->sub, type))
+ return 0; /* family types differ, do nothing */
+ cur_sub->sub.subtype = type.subtype; /* new subtype assignment */
+ return 1;
+}
+
+static inline int _event_hdl_resub_async(struct event_hdl_sub *cur_sub, struct event_hdl_sub_type type)
+{
+ int status = 0;
+ struct mt_list lock;
+
+ lock = MT_LIST_LOCK_ELT(&cur_sub->mt_list);
+ if (lock.next != &cur_sub->mt_list)
+ status = _event_hdl_resub(cur_sub, type);
+ // else already removed
+ MT_LIST_UNLOCK_ELT(&cur_sub->mt_list, lock);
+ return status;
+}
+
+static inline void _event_hdl_unsubscribe(struct event_hdl_sub *del_sub)
+{
+ struct mt_list lock;
+
+ if (del_sub->hdl.async) {
+ /* ASYNC SUB MODE */
+ /* push EVENT_HDL_SUB_END (to notify the task that the subscription is dead) */
+
+ /* push END EVENT in busy state so we can safely wakeup
+ * the task before releasing it.
+ * Not doing that would expose us to a race where the task could've already
+ * consumed the END event before the wakeup, and some tasks
+ * kill themselves (ie: normal async mode) when they receive such event
+ */
+ HA_ATOMIC_INC(&del_sub->hdl.async_equeue->size);
+ lock = MT_LIST_APPEND_LOCKED(&del_sub->hdl.async_equeue->head, &del_sub->async_end->mt_list);
+
+ /* wake up the task */
+ event_hdl_task_wakeup(del_sub->hdl.async_task);
+
+ /* unlock END EVENT (we're done, the task is now free to consume it) */
+ MT_LIST_UNLOCK_ELT(&del_sub->async_end->mt_list, lock);
+
+ /* we don't free sub here
+ * freeing will be performed by async task so it can safely rely
+ * on the pointer until it notices it
+ */
+ } else {
+ /* SYNC SUB MODE */
+
+ /* we can directly free the subscription:
+ * no other thread can access it since we successfully
+ * removed it from the list
+ */
+ event_hdl_drop(del_sub);
+ }
+}
+
+static inline void _event_hdl_unsubscribe_async(struct event_hdl_sub *del_sub)
+{
+ if (!MT_LIST_DELETE(&del_sub->mt_list))
+ return; /* already removed (but may be pending in e_queues) */
+ _event_hdl_unsubscribe(del_sub);
+}
+
+/* sub_mgmt function pointers (for handlers) */
+static struct event_hdl_sub_type event_hdl_getsub_sync(const struct event_hdl_sub_mgmt *mgmt)
+{
+ if (!mgmt)
+ return EVENT_HDL_SUB_NONE;
+
+ if (!mgmt->this)
+ return EVENT_HDL_SUB_NONE; /* already removed from sync ctx */
+ return _event_hdl_getsub(mgmt->this);
+}
+
+static struct event_hdl_sub_type event_hdl_getsub_async(const struct event_hdl_sub_mgmt *mgmt)
+{
+ if (!mgmt)
+ return EVENT_HDL_SUB_NONE;
+
+ return _event_hdl_getsub_async(mgmt->this);
+}
+
+static int event_hdl_resub_sync(const struct event_hdl_sub_mgmt *mgmt, struct event_hdl_sub_type type)
+{
+ if (!mgmt)
+ return 0;
+
+ if (!mgmt->this)
+ return 0; /* already removed from sync ctx */
+ return _event_hdl_resub(mgmt->this, type);
+}
+
+static int event_hdl_resub_async(const struct event_hdl_sub_mgmt *mgmt, struct event_hdl_sub_type type)
+{
+ if (!mgmt)
+ return 0;
+
+ return _event_hdl_resub_async(mgmt->this, type);
+}
+
+static void event_hdl_unsubscribe_sync(const struct event_hdl_sub_mgmt *mgmt)
+{
+ if (!mgmt)
+ return;
+
+ if (!mgmt->this)
+ return; /* already removed from sync ctx */
+
+ /* assuming that publish sync code will notice that mgmt->this is NULL
+ * and will perform the list removal using MT_LIST_DELETE_SAFE and
+ * _event_hdl_unsubscribe()
+ * while still owning the lock
+ */
+ ((struct event_hdl_sub_mgmt *)mgmt)->this = NULL;
+}
+
+static void event_hdl_unsubscribe_async(const struct event_hdl_sub_mgmt *mgmt)
+{
+ if (!mgmt)
+ return;
+
+ _event_hdl_unsubscribe_async(mgmt->this);
+}
+
+#define EVENT_HDL_SUB_MGMT_ASYNC(_sub) (struct event_hdl_sub_mgmt){ .this = _sub, \
+ .getsub = event_hdl_getsub_async, \
+ .resub = event_hdl_resub_async, \
+ .unsub = event_hdl_unsubscribe_async}
+#define EVENT_HDL_SUB_MGMT_SYNC(_sub) (struct event_hdl_sub_mgmt){ .this = _sub, \
+ .getsub = event_hdl_getsub_sync, \
+ .resub = event_hdl_resub_sync, \
+ .unsub = event_hdl_unsubscribe_sync}
+
+struct event_hdl_sub *event_hdl_subscribe_ptr(event_hdl_sub_list *sub_list,
+ struct event_hdl_sub_type e_type, struct event_hdl hdl)
+{
+ struct event_hdl_sub *new_sub = NULL;
+ struct mt_list *elt1, elt2;
+ struct event_hdl_async_task_default_ctx *task_ctx = NULL;
+ struct mt_list lock;
+
+ if (!sub_list)
+ sub_list = &global_event_hdl_sub_list; /* fall back to global list */
+
+ /* hdl API consistency check */
+ /*FIXME: do we need to ensure that if private is set, private_free should be set as well? */
+ BUG_ON((!hdl.async && !hdl.sync_ptr) ||
+ (hdl.async == EVENT_HDL_ASYNC_MODE_NORMAL && !hdl.async_ptr) ||
+ (hdl.async == EVENT_HDL_ASYNC_MODE_ADVANCED &&
+ (!hdl.async_equeue || !hdl.async_task)));
+
+ new_sub = pool_alloc(pool_head_sub);
+ if (new_sub == NULL) {
+ goto memory_error;
+ }
+
+ /* assignments */
+ new_sub->sub.family = e_type.family;
+ new_sub->sub.subtype = e_type.subtype;
+ new_sub->flags = 0;
+ new_sub->hdl = hdl;
+
+ if (hdl.async) {
+ /* async END event pre-allocation */
+ new_sub->async_end = pool_alloc(pool_head_sub_event);
+ if (!new_sub->async_end) {
+ /* memory error */
+ goto memory_error;
+ }
+ if (hdl.async == EVENT_HDL_ASYNC_MODE_NORMAL) {
+ /* normal mode: no task provided, we must initialize it */
+
+ /* initialize task context */
+ task_ctx = pool_alloc(pool_head_sub_taskctx);
+
+ if (!task_ctx) {
+ /* memory error */
+ goto memory_error;
+ }
+ event_hdl_async_equeue_init(&task_ctx->e_queue);
+ task_ctx->func = new_sub->hdl.async_ptr;
+
+ new_sub->hdl.async_equeue = &task_ctx->e_queue;
+ new_sub->hdl.async_task = tasklet_new();
+
+ if (!new_sub->hdl.async_task) {
+ /* memory error */
+ goto memory_error;
+ }
+ new_sub->hdl.async_task->context = task_ctx;
+ new_sub->hdl.async_task->process = event_hdl_async_task_default;
+ }
+ /* initialize END event (used to notify about subscription ending)
+ * used by both normal and advanced mode:
+ * - to safely terminate the task in normal mode
+ * - to safely free subscription and
+ * keep track of active subscriptions in advanced mode
+ */
+ new_sub->async_end->type = EVENT_HDL_SUB_END;
+ new_sub->async_end->sub_mgmt = EVENT_HDL_SUB_MGMT_ASYNC(new_sub);
+ new_sub->async_end->private = new_sub->hdl.private;
+ new_sub->async_end->_data = NULL;
+ MT_LIST_INIT(&new_sub->async_end->mt_list);
+ }
+ /* set refcount to 2:
+ * 1 for handler (because handler can manage the subscription itself)
+ * 1 for caller (will be dropped automatically if caller use the non-ptr version)
+ */
+ new_sub->refcount = 2;
+
+ /* ready for registration */
+ MT_LIST_INIT(&new_sub->mt_list);
+
+ lock = MT_LIST_LOCK_ELT(&sub_list->known);
+
+ /* check if such identified hdl is not already registered */
+ if (hdl.id) {
+ struct event_hdl_sub *cur_sub;
+ uint8_t found = 0;
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ if (hdl.id == cur_sub->hdl.id) {
+ /* we found matching registered hdl */
+ found = 1;
+ break;
+ }
+ }
+ if (found) {
+ /* error already registered */
+ MT_LIST_UNLOCK_ELT(&sub_list->known, lock);
+ event_hdl_report_hdl_state(ha_alert, &hdl, "SUB", "could not subscribe: subscription with this id already exists");
+ goto cleanup;
+ }
+ }
+
+ if (lock.next == &sub_list->known) {
+ /* this is an expected corner case on de-init path, a subscribe attempt
+ * was made but the subscription list is already destroyed, we pretend
+ * it is a memory/IO error since it should not be long before haproxy
+ * enters the deinit() function anyway
+ */
+ MT_LIST_UNLOCK_ELT(&sub_list->known, lock);
+ goto cleanup;
+ }
+
+ /* Append in list (global or user specified list).
+ * For now, append when sync mode, and insert when async mode
+ * so that async handlers are executed first
+ */
+ if (hdl.async) {
+ /* Prevent the task from being aborted on soft-stop: let's wait
+ * until the END event is acknowledged by the task.
+ * (decrease is performed in event_hdl_async_free_event())
+ *
+ * If we don't do this, event_hdl API will leak and we won't give
+ * a chance to the event-handling task to perform cleanup
+ */
+ HA_ATOMIC_INC(&jobs);
+ /* async mode, insert at the beginning of the list */
+ MT_LIST_INSERT(&sub_list->head, &new_sub->mt_list);
+ } else {
+ /* sync mode, append at the end of the list */
+ MT_LIST_APPEND(&sub_list->head, &new_sub->mt_list);
+ }
+
+ MT_LIST_UNLOCK_ELT(&sub_list->known, lock);
+
+ return new_sub;
+
+ cleanup:
+ if (new_sub) {
+ if (hdl.async == EVENT_HDL_ASYNC_MODE_NORMAL) {
+ tasklet_free(new_sub->hdl.async_task);
+ pool_free(pool_head_sub_taskctx, task_ctx);
+ }
+ if (hdl.async)
+ pool_free(pool_head_sub_event, new_sub->async_end);
+ pool_free(pool_head_sub, new_sub);
+ }
+
+ return NULL;
+
+ memory_error:
+ event_hdl_report_hdl_state(ha_warning, &hdl, "SUB", "could not register subscription due to memory error");
+ goto cleanup;
+}
+
+void event_hdl_take(struct event_hdl_sub *sub)
+{
+ HA_ATOMIC_INC(&sub->refcount);
+}
+
+void event_hdl_drop(struct event_hdl_sub *sub)
+{
+ if (HA_ATOMIC_SUB_FETCH(&sub->refcount, 1) != 0)
+ return;
+
+ /* we were the last one holding a reference to event sub - free required */
+ if (sub->hdl.private_free) {
+ /* free private data if specified upon registration */
+ sub->hdl.private_free(sub->hdl.private);
+ }
+ pool_free(pool_head_sub, sub);
+}
+
+int event_hdl_resubscribe(struct event_hdl_sub *cur_sub, struct event_hdl_sub_type type)
+{
+ return _event_hdl_resub_async(cur_sub, type);
+}
+
+void _event_hdl_pause(struct event_hdl_sub *cur_sub)
+{
+ cur_sub->flags |= EHDL_SUB_F_PAUSED;
+}
+
+void event_hdl_pause(struct event_hdl_sub *cur_sub)
+{
+ struct mt_list lock;
+
+ lock = MT_LIST_LOCK_ELT(&cur_sub->mt_list);
+ if (lock.next != &cur_sub->mt_list)
+ _event_hdl_pause(cur_sub);
+ // else already removed
+ MT_LIST_UNLOCK_ELT(&cur_sub->mt_list, lock);
+}
+
+void _event_hdl_resume(struct event_hdl_sub *cur_sub)
+{
+ cur_sub->flags &= ~EHDL_SUB_F_PAUSED;
+}
+
+void event_hdl_resume(struct event_hdl_sub *cur_sub)
+{
+ struct mt_list lock;
+
+ lock = MT_LIST_LOCK_ELT(&cur_sub->mt_list);
+ if (lock.next != &cur_sub->mt_list)
+ _event_hdl_resume(cur_sub);
+ // else already removed
+ MT_LIST_UNLOCK_ELT(&cur_sub->mt_list, lock);
+}
+
+void event_hdl_unsubscribe(struct event_hdl_sub *del_sub)
+{
+ _event_hdl_unsubscribe_async(del_sub);
+ /* drop refcount, assuming caller no longer use ptr */
+ event_hdl_drop(del_sub);
+}
+
+int event_hdl_subscribe(event_hdl_sub_list *sub_list, struct event_hdl_sub_type e_type, struct event_hdl hdl)
+{
+ struct event_hdl_sub *sub;
+
+ sub = event_hdl_subscribe_ptr(sub_list, e_type, hdl);
+ if (sub) {
+ /* drop refcount because the user is not willing to hold a reference */
+ event_hdl_drop(sub);
+ return 1;
+ }
+ return 0;
+}
+
+/* Subscription external lookup functions
+ */
+int event_hdl_lookup_unsubscribe(event_hdl_sub_list *sub_list,
+ uint64_t lookup_id)
+{
+ struct event_hdl_sub *del_sub = NULL;
+ struct mt_list *elt1, elt2;
+ int found = 0;
+
+ if (!sub_list)
+ sub_list = &global_event_hdl_sub_list; /* fall back to global list */
+
+ mt_list_for_each_entry_safe(del_sub, &sub_list->head, mt_list, elt1, elt2) {
+ if (lookup_id == del_sub->hdl.id) {
+ /* we found matching registered hdl */
+ MT_LIST_DELETE_SAFE(elt1);
+ _event_hdl_unsubscribe(del_sub);
+ found = 1;
+ break; /* id is unique, stop searching */
+ }
+ }
+ return found;
+}
+
+int event_hdl_lookup_resubscribe(event_hdl_sub_list *sub_list,
+ uint64_t lookup_id, struct event_hdl_sub_type type)
+{
+ struct event_hdl_sub *cur_sub = NULL;
+ struct mt_list *elt1, elt2;
+ int status = 0;
+
+ if (!sub_list)
+ sub_list = &global_event_hdl_sub_list; /* fall back to global list */
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ if (lookup_id == cur_sub->hdl.id) {
+ /* we found matching registered hdl */
+ status = _event_hdl_resub(cur_sub, type);
+ break; /* id is unique, stop searching */
+ }
+ }
+ return status;
+}
+
+int event_hdl_lookup_pause(event_hdl_sub_list *sub_list,
+ uint64_t lookup_id)
+{
+ struct event_hdl_sub *cur_sub = NULL;
+ struct mt_list *elt1, elt2;
+ int found = 0;
+
+ if (!sub_list)
+ sub_list = &global_event_hdl_sub_list; /* fall back to global list */
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ if (lookup_id == cur_sub->hdl.id) {
+ /* we found matching registered hdl */
+ _event_hdl_pause(cur_sub);
+ found = 1;
+ break; /* id is unique, stop searching */
+ }
+ }
+ return found;
+}
+
+int event_hdl_lookup_resume(event_hdl_sub_list *sub_list,
+ uint64_t lookup_id)
+{
+ struct event_hdl_sub *cur_sub = NULL;
+ struct mt_list *elt1, elt2;
+ int found = 0;
+
+ if (!sub_list)
+ sub_list = &global_event_hdl_sub_list; /* fall back to global list */
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ if (lookup_id == cur_sub->hdl.id) {
+ /* we found matching registered hdl */
+ _event_hdl_resume(cur_sub);
+ found = 1;
+ break; /* id is unique, stop searching */
+ }
+ }
+ return found;
+}
+
+struct event_hdl_sub *event_hdl_lookup_take(event_hdl_sub_list *sub_list,
+ uint64_t lookup_id)
+{
+ struct event_hdl_sub *cur_sub = NULL;
+ struct mt_list *elt1, elt2;
+ uint8_t found = 0;
+
+ if (!sub_list)
+ sub_list = &global_event_hdl_sub_list; /* fall back to global list */
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ if (lookup_id == cur_sub->hdl.id) {
+ /* we found matching registered hdl */
+ event_hdl_take(cur_sub);
+ found = 1;
+ break; /* id is unique, stop searching */
+ }
+ }
+ if (found)
+ return cur_sub;
+ return NULL;
+}
+
+/* event publishing functions
+ */
+static int _event_hdl_publish(event_hdl_sub_list *sub_list, struct event_hdl_sub_type e_type,
+ const struct event_hdl_cb_data *data)
+{
+ struct event_hdl_sub *cur_sub;
+ struct mt_list *elt1, elt2;
+ struct event_hdl_async_event_data *async_data = NULL; /* reuse async data for multiple async hdls */
+ int error = 0;
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ /* notify each function that has subscribed to sub_family.type, unless paused */
+ if ((cur_sub->sub.family == e_type.family) &&
+ ((cur_sub->sub.subtype & e_type.subtype) == e_type.subtype) &&
+ !(cur_sub->flags & EHDL_SUB_F_PAUSED)) {
+ /* hdl should be notified */
+ if (!cur_sub->hdl.async) {
+ /* sync mode: simply call cb pointer
+ * it is up to the callee to schedule a task if needed or
+ * take specific precautions in order to return as fast as possible
+ * and not use locks that are already held by the caller
+ */
+ struct event_hdl_cb cb;
+ struct event_hdl_sub_mgmt sub_mgmt;
+
+ sub_mgmt = EVENT_HDL_SUB_MGMT_SYNC(cur_sub);
+ cb.e_type = e_type;
+ if (data)
+ cb.e_data = data->_ptr;
+ else
+ cb.e_data = NULL;
+ cb.sub_mgmt = &sub_mgmt;
+ cb._sync = 1;
+
+ /* call user function */
+ cur_sub->hdl.sync_ptr(&cb, cur_sub->hdl.private);
+
+ if (!sub_mgmt.this) {
+ /* user has performed hdl unsub
+ * we must remove it from the list
+ */
+ MT_LIST_DELETE_SAFE(elt1);
+ /* then free it */
+ _event_hdl_unsubscribe(cur_sub);
+ }
+ } else {
+ /* async mode: here we need to prepare event data
+ * and push it to the event_queue of the task(s)
+ * responsible for consuming the events of current
+ * subscription.
+ * Once the event is pushed, we wake up the associated task.
+ * This feature depends on <haproxy/task> that also
+ * depends on <haproxy/pool>:
+ * If STG_PREPARE+STG_POOL is not performed prior to publishing to
+ * async handler, program may crash.
+ * Hopefully, STG_PREPARE+STG_POOL should be done early in
+ * HAProxy startup sequence.
+ */
+ struct event_hdl_async_event *new_event;
+
+ new_event = pool_alloc(pool_head_sub_event);
+ if (!new_event) {
+ error = 1;
+ break; /* stop on error */
+ }
+ new_event->type = e_type;
+ new_event->private = cur_sub->hdl.private;
+ new_event->when = date;
+ new_event->sub_mgmt = EVENT_HDL_SUB_MGMT_ASYNC(cur_sub);
+ if (data) {
+ /* if this fails, please adjust EVENT_HDL_ASYNC_EVENT_DATA in
+ * event_hdl-t.h file or consider providing dynamic struct members
+ * to reduce overall struct size
+ */
+ BUG_ON(data->_size > sizeof(async_data->data));
+ if (!async_data) {
+ /* first async hdl reached - preparing async_data cache */
+ async_data = pool_alloc(pool_head_sub_event_data);
+ if (!async_data) {
+ error = 1;
+ pool_free(pool_head_sub_event, new_event);
+ break; /* stop on error */
+ }
+
+ /* async data assignment */
+ memcpy(async_data->data, data->_ptr, data->_size);
+ async_data->mfree = data->_mfree;
+ /* Initialize refcount, we start at 1 to prevent async
+ * data from being freed by an async handler while we
+ * still use it. We will drop the reference when the
+ * publish is over.
+ *
+ * (first use, atomic operation not required)
+ */
+ async_data->refcount = 1;
+ }
+ new_event->_data = async_data;
+ new_event->data = async_data->data;
+ /* increment refcount because multiple hdls could
+ * use the same async_data
+ */
+ HA_ATOMIC_INC(&async_data->refcount);
+ } else
+ new_event->data = NULL;
+
+ /* appending new event to event hdl queue */
+ MT_LIST_INIT(&new_event->mt_list);
+ HA_ATOMIC_INC(&cur_sub->hdl.async_equeue->size);
+ MT_LIST_APPEND(&cur_sub->hdl.async_equeue->head, &new_event->mt_list);
+
+ /* wake up the task */
+ event_hdl_task_wakeup(cur_sub->hdl.async_task);
+ } /* end async mode */
+ } /* end hdl should be notified */
+ } /* end mt_list */
+ if (async_data) {
+ /* we finished publishing, drop the reference on async data */
+ _event_hdl_async_data_drop(async_data);
+ } else {
+ /* no async subscribers, we are responsible for calling the data
+ * member freeing function if it was provided
+ */
+ if (data && data->_mfree)
+ data->_mfree(data->_ptr);
+ }
+ if (error) {
+ event_hdl_report_hdl_state(ha_warning, &cur_sub->hdl, "PUBLISH", "memory error");
+ return 0;
+ }
+ return 1;
+}
+
+/* Publish function should not be used from high calling rate or time sensitive
+ * places for now, because list lookup based on e_type is not optimized at
+ * all!
+ * Returns 1 in case of SUCCESS:
+ * Subscribed handlers were notified successfully
+ * Returns 0 in case of FAILURE:
+ * FAILURE means memory error while handling the very first async handler from
+ * the subscription list.
+ * As async handlers are executed first within the list, when such failure occurs
+ * you can safely assume that no events were published for the current call
+ */
+int event_hdl_publish(event_hdl_sub_list *sub_list,
+ struct event_hdl_sub_type e_type, const struct event_hdl_cb_data *data)
+{
+ if (!e_type.family) {
+ /* do nothing, these types are reserved for internal use only
+ * (ie: unregistering) */
+ return 0;
+ }
+ if (sub_list) {
+ /* if sublist is provided, first publish event to list subscribers */
+ return _event_hdl_publish(sub_list, e_type, data);
+ } else {
+ /* publish to global list */
+ return _event_hdl_publish(&global_event_hdl_sub_list, e_type, data);
+ }
+}
+
+void event_hdl_sub_list_init(event_hdl_sub_list *sub_list)
+{
+ BUG_ON(!sub_list); /* unexpected, global sublist is managed internally */
+ MT_LIST_INIT(&sub_list->head);
+ MT_LIST_APPEND(&known_event_hdl_sub_list, &sub_list->known);
+}
+
+/* internal function, assumes that sub_list ptr is always valid */
+static void _event_hdl_sub_list_destroy(event_hdl_sub_list *sub_list)
+{
+ struct event_hdl_sub *cur_sub;
+ struct mt_list *elt1, elt2;
+
+ mt_list_for_each_entry_safe(cur_sub, &sub_list->head, mt_list, elt1, elt2) {
+ /* remove cur elem from list */
+ MT_LIST_DELETE_SAFE(elt1);
+ /* then free it */
+ _event_hdl_unsubscribe(cur_sub);
+ }
+}
+
+/* when a subscription list is no longer used, call this
+ * to do the cleanup and make sure all related subscriptions are
+ * safely ended according to their types
+ */
+void event_hdl_sub_list_destroy(event_hdl_sub_list *sub_list)
+{
+ BUG_ON(!sub_list); /* unexpected, global sublist is managed internally */
+ if (!MT_LIST_DELETE(&sub_list->known))
+ return; /* already destroyed */
+ _event_hdl_sub_list_destroy(sub_list);
+}
+
+/* config parser for global "tune.events.max-events-at-once" */
+static int event_hdl_parse_max_events_at_once(char **args, int section_type, struct proxy *curpx,
+ const struct proxy *defpx, const char *file, int line,
+ char **err)
+{
+ int arg = -1;
+
+ if (too_many_args(1, args, err, NULL))
+ return -1;
+
+ if (*(args[1]) != 0)
+ arg = atoi(args[1]);
+
+ if (arg < 1 || arg > 10000) {
+ memprintf(err, "'%s' expects an integer argument between 1 and 10000.", args[0]);
+ return -1;
+ }
+
+ event_hdl_tune.max_events_at_once = arg;
+ return 0;
+}
+
+/* config keyword parsers */
+static struct cfg_kw_list cfg_kws = {ILH, {
+ { CFG_GLOBAL, "tune.events.max-events-at-once", event_hdl_parse_max_events_at_once },
+ { 0, NULL, NULL }
+}};
+
+INITCALL1(STG_REGISTER, cfg_register_keywords, &cfg_kws);
+
+INITCALL0(STG_INIT, event_hdl_init);