diff options
Diffstat (limited to 'src/event_hdl.c')
| -rw-r--r-- | src/event_hdl.c | 999 |
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); |