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Diffstat (limited to 'libevent/event-internal.h')
| -rw-r--r-- | libevent/event-internal.h | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/libevent/event-internal.h b/libevent/event-internal.h new file mode 100644 index 0000000..9e5ff42 --- /dev/null +++ b/libevent/event-internal.h @@ -0,0 +1,488 @@ +/* + * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu> + * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#ifndef EVENT_INTERNAL_H_INCLUDED_ +#define EVENT_INTERNAL_H_INCLUDED_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include "event2/event-config.h" +#include "evconfig-private.h" + +#include <time.h> +#include <sys/queue.h> +#include "event2/event_struct.h" +#include "minheap-internal.h" +#include "evsignal-internal.h" +#include "mm-internal.h" +#include "defer-internal.h" + +/* map union members back */ + +/* mutually exclusive */ +#define ev_signal_next ev_.ev_signal.ev_signal_next +#define ev_io_next ev_.ev_io.ev_io_next +#define ev_io_timeout ev_.ev_io.ev_timeout + +/* used only by signals */ +#define ev_ncalls ev_.ev_signal.ev_ncalls +#define ev_pncalls ev_.ev_signal.ev_pncalls + +#define ev_pri ev_evcallback.evcb_pri +#define ev_flags ev_evcallback.evcb_flags +#define ev_closure ev_evcallback.evcb_closure +#define ev_callback ev_evcallback.evcb_cb_union.evcb_callback +#define ev_arg ev_evcallback.evcb_arg + +/** @name Event closure codes + + Possible values for evcb_closure in struct event_callback + + @{ + */ +/** A regular event. Uses the evcb_callback callback */ +#define EV_CLOSURE_EVENT 0 +/** A signal event. Uses the evcb_callback callback */ +#define EV_CLOSURE_EVENT_SIGNAL 1 +/** A persistent non-signal event. Uses the evcb_callback callback */ +#define EV_CLOSURE_EVENT_PERSIST 2 +/** A simple callback. Uses the evcb_selfcb callback. */ +#define EV_CLOSURE_CB_SELF 3 +/** A finalizing callback. Uses the evcb_cbfinalize callback. */ +#define EV_CLOSURE_CB_FINALIZE 4 +/** A finalizing event. Uses the evcb_evfinalize callback. */ +#define EV_CLOSURE_EVENT_FINALIZE 5 +/** A finalizing event that should get freed after. Uses the evcb_evfinalize + * callback. */ +#define EV_CLOSURE_EVENT_FINALIZE_FREE 6 +/** @} */ + +/** Structure to define the backend of a given event_base. */ +struct eventop { + /** The name of this backend. */ + const char *name; + /** Function to set up an event_base to use this backend. It should + * create a new structure holding whatever information is needed to + * run the backend, and return it. The returned pointer will get + * stored by event_init into the event_base.evbase field. On failure, + * this function should return NULL. */ + void *(*init)(struct event_base *); + /** Enable reading/writing on a given fd or signal. 'events' will be + * the events that we're trying to enable: one or more of EV_READ, + * EV_WRITE, EV_SIGNAL, and EV_ET. 'old' will be those events that + * were enabled on this fd previously. 'fdinfo' will be a structure + * associated with the fd by the evmap; its size is defined by the + * fdinfo field below. It will be set to 0 the first time the fd is + * added. The function should return 0 on success and -1 on error. + */ + int (*add)(struct event_base *, evutil_socket_t fd, short old, short events, void *fdinfo); + /** As "add", except 'events' contains the events we mean to disable. */ + int (*del)(struct event_base *, evutil_socket_t fd, short old, short events, void *fdinfo); + /** Function to implement the core of an event loop. It must see which + added events are ready, and cause event_active to be called for each + active event (usually via event_io_active or such). It should + return 0 on success and -1 on error. + */ + int (*dispatch)(struct event_base *, struct timeval *); + /** Function to clean up and free our data from the event_base. */ + void (*dealloc)(struct event_base *); + /** Flag: set if we need to reinitialize the event base after we fork. + */ + int need_reinit; + /** Bit-array of supported event_method_features that this backend can + * provide. */ + enum event_method_feature features; + /** Length of the extra information we should record for each fd that + has one or more active events. This information is recorded + as part of the evmap entry for each fd, and passed as an argument + to the add and del functions above. + */ + size_t fdinfo_len; +}; + +#ifdef _WIN32 +/* If we're on win32, then file descriptors are not nice low densely packed + integers. Instead, they are pointer-like windows handles, and we want to + use a hashtable instead of an array to map fds to events. +*/ +#define EVMAP_USE_HT +#endif + +/* #define HT_CACHE_HASH_VALS */ + +#ifdef EVMAP_USE_HT +#define HT_NO_CACHE_HASH_VALUES +#include "ht-internal.h" +struct event_map_entry; +HT_HEAD(event_io_map, event_map_entry); +#else +#define event_io_map event_signal_map +#endif + +/* Used to map signal numbers to a list of events. If EVMAP_USE_HT is not + defined, this structure is also used as event_io_map, which maps fds to a + list of events. +*/ +struct event_signal_map { + /* An array of evmap_io * or of evmap_signal *; empty entries are + * set to NULL. */ + void **entries; + /* The number of entries available in entries */ + int nentries; +}; + +/* A list of events waiting on a given 'common' timeout value. Ordinarily, + * events waiting for a timeout wait on a minheap. Sometimes, however, a + * queue can be faster. + **/ +struct common_timeout_list { + /* List of events currently waiting in the queue. */ + struct event_list events; + /* 'magic' timeval used to indicate the duration of events in this + * queue. */ + struct timeval duration; + /* Event that triggers whenever one of the events in the queue is + * ready to activate */ + struct event timeout_event; + /* The event_base that this timeout list is part of */ + struct event_base *base; +}; + +/** Mask used to get the real tv_usec value from a common timeout. */ +#define COMMON_TIMEOUT_MICROSECONDS_MASK 0x000fffff + +struct event_change; + +/* List of 'changes' since the last call to eventop.dispatch. Only maintained + * if the backend is using changesets. */ +struct event_changelist { + struct event_change *changes; + int n_changes; + int changes_size; +}; + +#ifndef EVENT__DISABLE_DEBUG_MODE +/* Global internal flag: set to one if debug mode is on. */ +extern int event_debug_mode_on_; +#define EVENT_DEBUG_MODE_IS_ON() (event_debug_mode_on_) +#else +#define EVENT_DEBUG_MODE_IS_ON() (0) +#endif + +TAILQ_HEAD(evcallback_list, event_callback); + +/* Sets up an event for processing once */ +struct event_once { + LIST_ENTRY(event_once) next_once; + struct event ev; + + void (*cb)(evutil_socket_t, short, void *); + void *arg; +}; + +struct event_base { + /** Function pointers and other data to describe this event_base's + * backend. */ + const struct eventop *evsel; + /** Pointer to backend-specific data. */ + void *evbase; + + /** List of changes to tell backend about at next dispatch. Only used + * by the O(1) backends. */ + struct event_changelist changelist; + + /** Function pointers used to describe the backend that this event_base + * uses for signals */ + const struct eventop *evsigsel; + /** Data to implement the common signal handler code. */ + struct evsig_info sig; + + /** Number of virtual events */ + int virtual_event_count; + /** Maximum number of virtual events active */ + int virtual_event_count_max; + /** Number of total events added to this event_base */ + int event_count; + /** Maximum number of total events added to this event_base */ + int event_count_max; + /** Number of total events active in this event_base */ + int event_count_active; + /** Maximum number of total events active in this event_base */ + int event_count_active_max; + + /** Set if we should terminate the loop once we're done processing + * events. */ + int event_gotterm; + /** Set if we should terminate the loop immediately */ + int event_break; + /** Set if we should start a new instance of the loop immediately. */ + int event_continue; + + /** The currently running priority of events */ + int event_running_priority; + + /** Set if we're running the event_base_loop function, to prevent + * reentrant invocation. */ + int running_loop; + + /** Set to the number of deferred_cbs we've made 'active' in the + * loop. This is a hack to prevent starvation; it would be smarter + * to just use event_config_set_max_dispatch_interval's max_callbacks + * feature */ + int n_deferreds_queued; + + /* Active event management. */ + /** An array of nactivequeues queues for active event_callbacks (ones + * that have triggered, and whose callbacks need to be called). Low + * priority numbers are more important, and stall higher ones. + */ + struct evcallback_list *activequeues; + /** The length of the activequeues array */ + int nactivequeues; + /** A list of event_callbacks that should become active the next time + * we process events, but not this time. */ + struct evcallback_list active_later_queue; + + /* common timeout logic */ + + /** An array of common_timeout_list* for all of the common timeout + * values we know. */ + struct common_timeout_list **common_timeout_queues; + /** The number of entries used in common_timeout_queues */ + int n_common_timeouts; + /** The total size of common_timeout_queues. */ + int n_common_timeouts_allocated; + + /** Mapping from file descriptors to enabled (added) events */ + struct event_io_map io; + + /** Mapping from signal numbers to enabled (added) events. */ + struct event_signal_map sigmap; + + /** Priority queue of events with timeouts. */ + struct min_heap timeheap; + + /** Stored timeval: used to avoid calling gettimeofday/clock_gettime + * too often. */ + struct timeval tv_cache; + + struct evutil_monotonic_timer monotonic_timer; + + /** Difference between internal time (maybe from clock_gettime) and + * gettimeofday. */ + struct timeval tv_clock_diff; + /** Second in which we last updated tv_clock_diff, in monotonic time. */ + time_t last_updated_clock_diff; + +#ifndef EVENT__DISABLE_THREAD_SUPPORT + /* threading support */ + /** The thread currently running the event_loop for this base */ + unsigned long th_owner_id; + /** A lock to prevent conflicting accesses to this event_base */ + void *th_base_lock; + /** A condition that gets signalled when we're done processing an + * event with waiters on it. */ + void *current_event_cond; + /** Number of threads blocking on current_event_cond. */ + int current_event_waiters; +#endif + /** The event whose callback is executing right now */ + struct event_callback *current_event; + +#ifdef _WIN32 + /** IOCP support structure, if IOCP is enabled. */ + struct event_iocp_port *iocp; +#endif + + /** Flags that this base was configured with */ + enum event_base_config_flag flags; + + struct timeval max_dispatch_time; + int max_dispatch_callbacks; + int limit_callbacks_after_prio; + + /* Notify main thread to wake up break, etc. */ + /** True if the base already has a pending notify, and we don't need + * to add any more. */ + int is_notify_pending; + /** A socketpair used by some th_notify functions to wake up the main + * thread. */ + evutil_socket_t th_notify_fd[2]; + /** An event used by some th_notify functions to wake up the main + * thread. */ + struct event th_notify; + /** A function used to wake up the main thread from another thread. */ + int (*th_notify_fn)(struct event_base *base); + + /** Saved seed for weak random number generator. Some backends use + * this to produce fairness among sockets. Protected by th_base_lock. */ + struct evutil_weakrand_state weakrand_seed; + + /** List of event_onces that have not yet fired. */ + LIST_HEAD(once_event_list, event_once) once_events; + +}; + +struct event_config_entry { + TAILQ_ENTRY(event_config_entry) next; + + const char *avoid_method; +}; + +/** Internal structure: describes the configuration we want for an event_base + * that we're about to allocate. */ +struct event_config { + TAILQ_HEAD(event_configq, event_config_entry) entries; + + int n_cpus_hint; + struct timeval max_dispatch_interval; + int max_dispatch_callbacks; + int limit_callbacks_after_prio; + enum event_method_feature require_features; + enum event_base_config_flag flags; +}; + +/* Internal use only: Functions that might be missing from <sys/queue.h> */ +#ifndef LIST_END +#define LIST_END(head) NULL +#endif + +#ifndef TAILQ_FIRST +#define TAILQ_FIRST(head) ((head)->tqh_first) +#endif +#ifndef TAILQ_END +#define TAILQ_END(head) NULL +#endif +#ifndef TAILQ_NEXT +#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) +#endif + +#ifndef TAILQ_FOREACH +#define TAILQ_FOREACH(var, head, field) \ + for ((var) = TAILQ_FIRST(head); \ + (var) != TAILQ_END(head); \ + (var) = TAILQ_NEXT(var, field)) +#endif + +#ifndef TAILQ_INSERT_BEFORE +#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ + (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ + (elm)->field.tqe_next = (listelm); \ + *(listelm)->field.tqe_prev = (elm); \ + (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ +} while (0) +#endif + +#define N_ACTIVE_CALLBACKS(base) \ + ((base)->event_count_active) + +int evsig_set_handler_(struct event_base *base, int evsignal, + void (*fn)(int)); +int evsig_restore_handler_(struct event_base *base, int evsignal); + +int event_add_nolock_(struct event *ev, + const struct timeval *tv, int tv_is_absolute); +/** Argument for event_del_nolock_. Tells event_del not to block on the event + * if it's running in another thread. */ +#define EVENT_DEL_NOBLOCK 0 +/** Argument for event_del_nolock_. Tells event_del to block on the event + * if it's running in another thread, regardless of its value for EV_FINALIZE + */ +#define EVENT_DEL_BLOCK 1 +/** Argument for event_del_nolock_. Tells event_del to block on the event + * if it is running in another thread and it doesn't have EV_FINALIZE set. + */ +#define EVENT_DEL_AUTOBLOCK 2 +/** Argument for event_del_nolock_. Tells event_del to proceed even if the + * event is set up for finalization rather for regular use.*/ +#define EVENT_DEL_EVEN_IF_FINALIZING 3 +int event_del_nolock_(struct event *ev, int blocking); +int event_remove_timer_nolock_(struct event *ev); + +void event_active_nolock_(struct event *ev, int res, short count); +EVENT2_EXPORT_SYMBOL +int event_callback_activate_(struct event_base *, struct event_callback *); +int event_callback_activate_nolock_(struct event_base *, struct event_callback *); +int event_callback_cancel_(struct event_base *base, + struct event_callback *evcb); + +void event_callback_finalize_nolock_(struct event_base *base, unsigned flags, struct event_callback *evcb, void (*cb)(struct event_callback *, void *)); +EVENT2_EXPORT_SYMBOL +void event_callback_finalize_(struct event_base *base, unsigned flags, struct event_callback *evcb, void (*cb)(struct event_callback *, void *)); +int event_callback_finalize_many_(struct event_base *base, int n_cbs, struct event_callback **evcb, void (*cb)(struct event_callback *, void *)); + + +EVENT2_EXPORT_SYMBOL +void event_active_later_(struct event *ev, int res); +void event_active_later_nolock_(struct event *ev, int res); +int event_callback_activate_later_nolock_(struct event_base *base, + struct event_callback *evcb); +int event_callback_cancel_nolock_(struct event_base *base, + struct event_callback *evcb, int even_if_finalizing); +void event_callback_init_(struct event_base *base, + struct event_callback *cb); + +/* FIXME document. */ +EVENT2_EXPORT_SYMBOL +void event_base_add_virtual_(struct event_base *base); +void event_base_del_virtual_(struct event_base *base); + +/** For debugging: unless assertions are disabled, verify the referential + integrity of the internal data structures of 'base'. This operation can + be expensive. + + Returns on success; aborts on failure. +*/ +EVENT2_EXPORT_SYMBOL +void event_base_assert_ok_(struct event_base *base); +void event_base_assert_ok_nolock_(struct event_base *base); + + +/* Helper function: Call 'fn' exactly once every inserted or active event in + * the event_base 'base'. + * + * If fn returns 0, continue on to the next event. Otherwise, return the same + * value that fn returned. + * + * Requires that 'base' be locked. + */ +int event_base_foreach_event_nolock_(struct event_base *base, + event_base_foreach_event_cb cb, void *arg); + +/* Cleanup function to reset debug mode during shutdown. + * + * Calling this function doesn't mean it'll be possible to re-enable + * debug mode if any events were added. + */ +void event_disable_debug_mode(void); + +#ifdef __cplusplus +} +#endif + +#endif /* EVENT_INTERNAL_H_INCLUDED_ */ |