/*
* IRC - Internet Relay Chat, ircd/ircd_events.c
* Copyright (C) 2001 Kevin L. Mitchell <klmitch@mit.edu>
*
* 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 1, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: ircd_events.c 579 2003-11-21 04:39:57Z r33d $
*/
#include "config.h"
#include "ircd_events.h"
#include "ircd.h"
#include "ircd_alloc.h"
#include "ircd_log.h"
#include "ircd_snprintf.h"
#include "s_debug.h"
#include <assert.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#define SIGS_PER_SOCK 10 /* number of signals to process per socket
readable event */
#ifdef USE_KQUEUE
extern struct Engine engine_kqueue;
#define ENGINE_KQUEUE &engine_kqueue,
#else
#define ENGINE_KQUEUE
#endif /* USE_KQUEUE */
#ifdef USE_DEVPOLL
extern struct Engine engine_devpoll;
#define ENGINE_DEVPOLL &engine_devpoll,
#else
#define ENGINE_DEVPOLL
#endif /* USE_DEVPOLL */
#ifdef USE_EPOLL
extern struct Engine engine_epoll;
#define ENGINE_EPOLL &engine_epoll,
#else
#define ENGINE_EPOLL
#endif /* USE_EPOLL */
#ifdef USE_POLL
extern struct Engine engine_poll;
#define ENGINE_FALLBACK &engine_poll,
#else
extern struct Engine engine_select;
#define ENGINE_FALLBACK &engine_select,
#endif /* USE_POLL */
/* list of engines to try */
static const struct Engine *evEngines[] = {
ENGINE_KQUEUE
ENGINE_EPOLL
ENGINE_DEVPOLL
ENGINE_FALLBACK
0
};
/* signal routines pipe data */
static struct {
int fd; /* signal routine's fd */
struct Socket sock; /* and its struct Socket */
} sigInfo = { -1 };
/* All the thread info */
static struct {
struct Generators gens; /* List of all generators */
struct Event* events_free; /* struct Event free list */
unsigned int events_alloc; /* count of allocated struct Events */
const struct Engine* engine; /* core engine being used */
#ifdef IRCD_THREADED
struct GenHeader* genq_head; /* head of generator event queue */
struct GenHeader* genq_tail; /* tail of generator event queue */
unsigned int genq_count; /* count of generators on queue */
#endif
} evInfo = {
{ 0, 0, 0 },
0, 0, 0
#ifdef IRCD_THREADED
, 0, 0, 0
#endif
};
/* Initialize a struct GenHeader */
static void
gen_init(struct GenHeader* gen, EventCallBack call, void* data,
struct GenHeader* next, struct GenHeader** prev_p)
{
assert(0 != gen);
gen->gh_next = next;
gen->gh_prev_p = prev_p;
#ifdef IRCD_THREADED
gen->gh_qnext = 0;
gen->gh_qprev_p = 0;
gen->gh_head = 0;
gen->gh_tail = 0;
#endif
gen->gh_flags = GEN_ACTIVE;
gen->gh_ref = 0;
gen->gh_call = call;
gen->gh_data = data;
gen->gh_engdata.ed_int = 0;
if (prev_p) { /* Going to link into list? */
if (next) /* do so */
next->gh_prev_p = &gen->gh_next;
*prev_p = gen;
}
}
/* Execute an event; optimizations should inline this */
static void
event_execute(struct Event* event)
{
assert(0 != event);
assert(0 == event->ev_prev_p); /* must be off queue first */
assert(event->ev_gen.gen_header->gh_flags & GEN_ACTIVE);
if (event->ev_type == ET_DESTROY) /* turn off active flag *before* destroy */
event->ev_gen.gen_header->gh_flags &= ~GEN_ACTIVE;
if (event->ev_type == ET_ERROR) /* turn on error flag before callback */
event->ev_gen.gen_header->gh_flags |= GEN_ERROR;
(*event->ev_gen.gen_header->gh_call)(event); /* execute the event */
/* The logic here is very careful; if the event was an ET_DESTROY,
* then we must assume the generator is now invalid; fortunately, we
* don't need to do anything to it if so. Otherwise, we decrement
* the reference count; if reference count goes to zero, AND we need
* to destroy the generator, THEN we generate a DESTROY event.
*/
if (event->ev_type != ET_DESTROY)
gen_ref_dec(event->ev_gen.gen_header);
event->ev_gen.gen_header = 0; /* clear event data */
event->ev_type = ET_DESTROY;
event->ev_next = evInfo.events_free; /* add to free list */
evInfo.events_free = event;
}
#ifndef IRCD_THREADED
/* we synchronously execute the event when not threaded */
#define event_add(event) \
do { \
struct Event* _ev = (event); \
_ev->ev_next = 0; \
_ev->ev_prev_p = 0; \
event_execute(_ev); \
} while (0)
#else
/* add an event to the work queue */
/* This is just a placeholder; don't expect ircd to be threaded soon */
/* There should be locks all over the place in here */
static void
event_add(struct Event* event)
{
struct GenHeader* gen;
assert(0 != event);
gen = event->ev_gen.gen_header;
/* First, place event on generator's event queue */
event->ev_next = 0;
if (gen->gh_head) {
assert(0 != gen->gh_tail);
event->ev_prev_p = &gen->gh_tail->ev_next;
gen->gh_tail->ev_next = event;
gen->gh_tail = event;
} else { /* queue was empty */
assert(0 == gen->gh_tail);
event->ev_prev_p = &gen->gh_head;
gen->gh_head = event;
gen->gh_tail = event;
}
/* Now, if the generator isn't on the queue yet... */
if (!gen->gh_qprev_p) {
gen->gh_qnext = 0;
if (evInfo.genq_head) {
assert(0 != evInfo.genq_tail);
gen->gh_qprev_p = &evInfo.genq_tail->gh_qnext;
evInfo.genq_tail->gh_qnext = gen;
evInfo.genq_tail = gen;
} else { /* queue was empty */
assert(0 == evInfo.genq_tail);
gen->gh_qprev_p = &evInfo.genq_head;
evInfo.genq_head = gen;
evInfo.genq_tail = gen;
}
/* We'd also have to signal the work crew here */
}
}
#endif /* IRCD_THREADED */
/* Place a timer in the correct spot on the queue */
static void
timer_enqueue(struct Timer* timer)
{
struct Timer** ptr_p;
assert(0 != timer);
assert(0 == timer->t_header.gh_prev_p); /* not already on queue */
assert(timer->t_header.gh_flags & GEN_ACTIVE); /* timer is active */
/* Calculate expire time */
switch (timer->t_type) {
case TT_ABSOLUTE: /* no need to consider it relative */
timer->t_expire = timer->t_value;
break;
case TT_RELATIVE: case TT_PERIODIC: /* relative timer */
timer->t_expire = timer->t_value + CurrentTime;
break;
}
/* Find a slot to insert timer */
for (ptr_p = &evInfo.gens.g_timer; ;
ptr_p = (struct Timer**) &(*ptr_p)->t_header.gh_next)
if (!*ptr_p || timer->t_expire < (*ptr_p)->t_expire)
break;
/* link it in the right place */
timer->t_header.gh_next = (struct GenHeader*) *ptr_p;
timer->t_header.gh_prev_p = (struct GenHeader**) ptr_p;
if (*ptr_p)
(*ptr_p)->t_header.gh_prev_p = &timer->t_header.gh_next;
*ptr_p = timer;
}
/* signal handler for writing signal notification to pipe */
static void
signal_handler(int sig)
{
unsigned char c;
assert(sigInfo.fd >= 0);
c = (unsigned char) sig; /* only write 1 byte to identify sig */
write(sigInfo.fd, &c, 1);
}
/* callback for signal "socket" events */
static void
signal_callback(struct Event* event)
{
unsigned char sigstr[SIGS_PER_SOCK];
int sig, n_sigs, i;
struct Signal* ptr;
assert(event->ev_type == ET_READ); /* readable events only */
n_sigs = read(event->ev_gen.gen_socket->s_fd, sigstr, sizeof(sigstr));
for (i = 0; i < n_sigs; i++) {
sig = (int) sigstr[i]; /* get signal */
for (ptr = evInfo.gens.g_signal; ptr;
ptr = (struct Signal*) ptr->sig_header.gh_next)
if (ptr->sig_signal == sig) /* find its descriptor... */
break;
if (ptr)
event_generate(ET_SIGNAL, ptr, sig); /* generate signal event */
}
}
/* Remove something from its queue */
void
gen_dequeue(void* arg)
{
struct GenHeader* gen = (struct GenHeader*) arg;
if (gen->gh_next) /* clip it out of the list */
gen->gh_next->gh_prev_p = gen->gh_prev_p;
if (gen->gh_prev_p)
*gen->gh_prev_p = gen->gh_next;
gen->gh_next = 0; /* mark that it's not in the list anymore */
gen->gh_prev_p = 0;
}
/* Initializes the event system */
void
event_init(int max_sockets)
{
int i, p[2];
for (i = 0; evEngines[i]; i++) { /* look for an engine... */
assert(0 != evEngines[i]->eng_name);
assert(0 != evEngines[i]->eng_init);
if ((*evEngines[i]->eng_init)(max_sockets))
break; /* Found an engine that'll work */
}
assert(0 != evEngines[i]);
evInfo.engine = evEngines[i]; /* save engine */
if (!evInfo.engine->eng_signal) { /* engine can't do signals */
if (pipe(p)) {
log_write(LS_SYSTEM, L_CRIT, 0, "Failed to open signal pipe");
exit(8);
}
sigInfo.fd = p[1]; /* write end of pipe */
socket_add(&sigInfo.sock, signal_callback, 0, SS_NOTSOCK,
SOCK_EVENT_READABLE, p[0]); /* read end of pipe */
}
}
/* Do the event loop */
void
event_loop(void)
{
assert(0 != evInfo.engine);
assert(0 != evInfo.engine->eng_loop);
(*evInfo.engine->eng_loop)(&evInfo.gens);
}
/* Generate an event and add it to the queue (or execute it) */
void
event_generate(enum EventType type, void* arg, int data)
{
struct Event* ptr;
struct GenHeader* gen = (struct GenHeader*) arg;
assert(0 != gen);
/* don't create events (other than ET_DESTROY) for destroyed generators */
if (type != ET_DESTROY && (gen->gh_flags & GEN_DESTROY))
return;
Debug((DEBUG_LIST, "Generating event type %s for generator %p (%s)",
event_to_name(type), gen, gen_flags(gen->gh_flags)));
if ((ptr = evInfo.events_free))
evInfo.events_free = ptr->ev_next; /* pop one off the freelist */
else { /* allocate another structure */
ptr = (struct Event*) MyMalloc(sizeof(struct Event));
evInfo.events_alloc++; /* count of allocated events */
}
ptr->ev_type = type; /* Record event type */
ptr->ev_data = data;
ptr->ev_gen.gen_header = (struct GenHeader*) gen;
ptr->ev_gen.gen_header->gh_ref++;
event_add(ptr); /* add event to queue */
}
#if 0
/* Try to verify the timer list */
void
timer_verify(void)
{
struct Timer* ptr;
struct Timer** ptr_p = &evInfo.gens.g_timer;
time_t lasttime = 0;
for (ptr = evInfo.gens.g_timer; ptr;
ptr = (struct Timer*) ptr->t_header.gh_next) {
/* verify timer is supposed to be in the list */
assert(ptr->t_header.gh_prev_p);
/* verify timer is correctly ordered */
assert((struct Timer**) ptr->t_header.gh_prev_p == ptr_p);
/* verify timer is active */
assert(ptr->t_header.gh_flags & GEN_ACTIVE);
/* verify timer ordering is correct */
assert(lasttime <= ptr->t_expire);
lasttime = ptr->t_expire; /* store time for ordering check */
ptr_p = (struct Timer**) &ptr->t_header.gh_next; /* store prev pointer */
}
}
#endif
/* Initialize a timer structure */
struct Timer*
timer_init(struct Timer* timer)
{
gen_init((struct GenHeader*) timer, 0, 0, 0, 0);
timer->t_header.gh_flags = 0; /* turn off active flag */
return timer; /* convenience return */
}
/* Add a timer to be processed */
void
timer_add(struct Timer* timer, EventCallBack call, void* data,
enum TimerType type, time_t value)
{
assert(0 != timer);
assert(0 != call);
Debug((DEBUG_LIST, "Adding timer %p; time out %Tu (type %s)", timer, value,
timer_to_name(type)));
/* initialize a timer... */
timer->t_header.gh_flags |= GEN_ACTIVE;
if (timer->t_header.gh_flags & GEN_MARKED)
timer->t_header.gh_flags |= GEN_READD;
timer->t_header.gh_ref = 0;
timer->t_header.gh_call = call;
timer->t_header.gh_data = data;
timer->t_type = type;
timer->t_value = value;
timer->t_expire = 0;
if (!(timer->t_header.gh_flags & GEN_MARKED))
timer_enqueue(timer); /* and enqueue it */
}
/* Remove a timer from the processing queue */
void
timer_del(struct Timer* timer)
{
assert(0 != timer);
timer->t_header.gh_flags &= ~GEN_READD;
if (timer->t_header.gh_flags & GEN_MARKED)
return; /* timer is being used */
Debug((DEBUG_LIST, "Deleting timer %p (type %s)", timer,
timer_to_name(timer->t_type)));
gen_dequeue(timer);
event_generate(ET_DESTROY, timer, 0);
}
/* Change the time a timer expires */
void
timer_chg(struct Timer* timer, enum TimerType type, time_t value)
{
assert(0 != timer);
assert(0 != value);
assert(TT_PERIODIC != timer->t_type);
assert(TT_PERIODIC != type);
Debug((DEBUG_LIST, "Changing timer %p from type %s timeout %Tu to type %s "
"timeout %Tu", timer, timer_to_name(timer->t_type), timer->t_value,
timer_to_name(type), value));
gen_dequeue(timer); /* remove the timer from the queue */
timer->t_type = type; /* Set the new type and value */
timer->t_value = value;
timer->t_expire = 0;
timer_enqueue(timer); /* re-queue the timer */
}
/* Execute all expired timers */
void
timer_run(void)
{
struct Timer* ptr;
/* go through queue... */
while ((ptr = evInfo.gens.g_timer)) {
if (CurrentTime < ptr->t_expire)
break; /* processed all pending timers */
gen_dequeue(ptr); /* must dequeue timer here */
ptr->t_header.gh_flags |= (GEN_MARKED |
(ptr->t_type == TT_PERIODIC ? GEN_READD : 0));
event_generate(ET_EXPIRE, ptr, 0); /* generate expire event */
ptr->t_header.gh_flags &= ~GEN_MARKED;
if (!(ptr->t_header.gh_flags & GEN_READD)) {
Debug((DEBUG_LIST, "Destroying timer %p", ptr));
event_generate(ET_DESTROY, ptr, 0);
} else {
Debug((DEBUG_LIST, "Re-enqueuing timer %p", ptr));
timer_enqueue(ptr); /* re-queue timer */
ptr->t_header.gh_flags &= ~GEN_READD;
}
}
}
/* Adds a signal to the event callback system */
void
signal_add(struct Signal* signal, EventCallBack call, void* data, int sig)
{
struct sigaction act;
assert(0 != signal);
assert(0 != call);
assert(0 != evInfo.engine);
/* set up struct */
gen_init((struct GenHeader*) signal, call, data,
(struct GenHeader*) evInfo.gens.g_signal,
(struct GenHeader**) &evInfo.gens.g_signal);
signal->sig_signal = sig;
if (evInfo.engine->eng_signal)
(*evInfo.engine->eng_signal)(signal); /* tell engine */
else {
act.sa_handler = signal_handler; /* set up signal handler */
act.sa_flags = 0;
sigemptyset(&act.sa_mask);
sigaction(sig, &act, 0);
}
}
/* Adds a socket to the event system */
int
socket_add(struct Socket* sock, EventCallBack call, void* data,
enum SocketState state, unsigned int events, int fd)
{
assert(0 != sock);
assert(0 != call);
assert(fd >= 0);
assert(0 != evInfo.engine);
assert(0 != evInfo.engine->eng_add);
/* set up struct */
gen_init((struct GenHeader*) sock, call, data,
(struct GenHeader*) evInfo.gens.g_socket,
(struct GenHeader**) &evInfo.gens.g_socket);
sock->s_state = state;
sock->s_events = events & SOCK_EVENT_MASK;
sock->s_fd = fd;
return (*evInfo.engine->eng_add)(sock); /* tell engine about it */
}
/* deletes (or marks for deletion) a socket */
void
socket_del(struct Socket* sock)
{
assert(0 != sock);
assert(!(sock->s_header.gh_flags & GEN_DESTROY));
assert(0 != evInfo.engine);
assert(0 != evInfo.engine->eng_closing);
/* tell engine socket is going away */
(*evInfo.engine->eng_closing)(sock);
sock->s_header.gh_flags |= GEN_DESTROY;
if (!sock->s_header.gh_ref) { /* not in use; destroy right now */
gen_dequeue(sock);
event_generate(ET_DESTROY, sock, 0);
}
}
/* Sets the socket state to something else */
void
socket_state(struct Socket* sock, enum SocketState state)
{
assert(0 != sock);
assert(0 != evInfo.engine);
assert(0 != evInfo.engine->eng_state);
/* assertions for invalid socket state transitions */
assert(sock->s_state != state); /* not changing states ?! */
assert(sock->s_state != SS_LISTENING); /* listening socket to...?! */
assert(sock->s_state != SS_CONNECTED); /* connected socket to...?! */
/* connecting socket now connected */
assert(sock->s_state != SS_CONNECTING || state == SS_CONNECTED);
/* unconnected datagram socket now connected */
assert(sock->s_state != SS_DATAGRAM || state == SS_CONNECTDG);
/* connected datagram socket now unconnected */
assert(sock->s_state != SS_CONNECTDG || state == SS_DATAGRAM);
/* Don't continue if an error occurred or the socket got destroyed */
if (sock->s_header.gh_flags & (GEN_DESTROY | GEN_ERROR))
return;
/* tell engine we're changing socket state */
(*evInfo.engine->eng_state)(sock, state);
sock->s_state = state; /* set new state */
}
/* sets the events a socket's interested in */
void
socket_events(struct Socket* sock, unsigned int events)
{
unsigned int new_events = 0;
assert(0 != sock);
assert(0 != evInfo.engine);
assert(0 != evInfo.engine->eng_events);
/* Don't continue if an error occurred or the socket got destroyed */
if (sock->s_header.gh_flags & (GEN_DESTROY | GEN_ERROR))
return;
switch (events & SOCK_ACTION_MASK) {
case SOCK_ACTION_SET: /* set events to given set */
new_events = events & SOCK_EVENT_MASK;
break;
case SOCK_ACTION_ADD: /* add some events */
new_events = sock->s_events | (events & SOCK_EVENT_MASK);
break;
case SOCK_ACTION_DEL: /* remove some events */
new_events = sock->s_events & ~(events & SOCK_EVENT_MASK);
break;
}
if (sock->s_events == new_events)
return; /* no changes have been made */
/* tell engine about event mask change */
(*evInfo.engine->eng_events)(sock, new_events);
sock->s_events = new_events; /* set new events */
}
/* Returns an engine's name for informational purposes */
const char*
engine_name(void)
{
assert(0 != evInfo.engine);
assert(0 != evInfo.engine->eng_name);
return evInfo.engine->eng_name;
}
#ifdef DEBUGMODE
/* These routines pretty-print names for states and types for debug printing */
#define NS(TYPE) \
struct { \
char *name; \
TYPE value; \
}
#define NM(name) { #name, name }
#define NE { 0, 0 }
const char*
state_to_name(enum SocketState state)
{
int i;
NS(enum SocketState) map[] = {
NM(SS_CONNECTING),
NM(SS_LISTENING),
NM(SS_CONNECTED),
NM(SS_DATAGRAM),
NM(SS_CONNECTDG),
NM(SS_NOTSOCK),
NE
};
for (i = 0; map[i].name; i++)
if (map[i].value == state)
return map[i].name;
return "Undefined socket state";
}
const char*
timer_to_name(enum TimerType type)
{
int i;
NS(enum TimerType) map[] = {
NM(TT_ABSOLUTE),
NM(TT_RELATIVE),
NM(TT_PERIODIC),
NE
};
for (i = 0; map[i].name; i++)
if (map[i].value == type)
return map[i].name;
return "Undefined timer type";
}
const char*
event_to_name(enum EventType type)
{
int i;
NS(enum EventType) map[] = {
NM(ET_READ),
NM(ET_WRITE),
NM(ET_ACCEPT),
NM(ET_CONNECT),
NM(ET_EOF),
NM(ET_ERROR),
NM(ET_SIGNAL),
NM(ET_EXPIRE),
NM(ET_DESTROY),
NE
};
for (i = 0; map[i].name; i++)
if (map[i].value == type)
return map[i].name;
return "Undefined event type";
}
const char*
gen_flags(unsigned int flags)
{
int i, loc = 0;
static char buf[256];
NS(unsigned int) map[] = {
NM(GEN_DESTROY),
NM(GEN_MARKED),
NM(GEN_ACTIVE),
NM(GEN_READD),
NM(GEN_ERROR),
NE
};
buf[0] = '\0';
for (i = 0; map[i].name; i++)
if (map[i].value & flags) {
if (loc != 0)
buf[loc++] = ' ';
loc += ircd_snprintf(0, buf + loc, sizeof(buf) - loc, "%s", map[i].name);
if (loc >= sizeof(buf))
return buf; /* overflow case */
}
return buf;
}
const char*
sock_flags(unsigned int flags)
{
int i, loc = 0;
static char buf[256];
NS(unsigned int) map[] = {
NM(SOCK_EVENT_READABLE),
NM(SOCK_EVENT_WRITABLE),
NM(SOCK_ACTION_SET),
NM(SOCK_ACTION_ADD),
NM(SOCK_ACTION_DEL),
NE
};
buf[0] = '\0';
for (i = 0; map[i].name; i++)
if (map[i].value & flags) {
if (loc != 0)
buf[loc++] = ' ';
loc += ircd_snprintf(0, buf + loc, sizeof(buf) - loc, "%s", map[i].name);
if (loc >= sizeof(buf))
return buf; /* overflow case */
}
return buf;
}
#endif /* DEBUGMODE */
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