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haproxy/src/event_hdl.c
Tim Duesterhus f88ea5949c CLEANUP: Reapply strcmp.cocci (2) 
This reapplies strcmp.cocci across the whole src/ tree.
2024-04-02 07:27:33 +02:00

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/*
* 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 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#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) == 0)
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);
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