freebsd-dev/contrib/libbegemot/rpoll.c

715 lines
16 KiB
C

/*
* Copyright (c)1996-2002 by Hartmut Brandt
* All rights reserved.
*
* Author: Hartmut Brandt
*
* Redistribution of this software and documentation 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 or documentation 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.
*
* THIS SOFTWARE AND DOCUMENTATION IS PROVIDED BY THE AUTHOR
* AND ITS CONTRIBUTORS ``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 OR ITS CONTRIBUTORS 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.
*/
/*
* These functions try to hide the poll/select/setitimer interface from the
* user. You associate callback functions with file descriptors and timers.
*
* $Begemot: libbegemot/rpoll.c,v 1.14 2004/09/21 15:59:00 brandt Exp $
*/
# include <stdio.h>
# include <stdlib.h>
# include <stddef.h>
# include <stdarg.h>
# include <signal.h>
# include <string.h>
# include <errno.h>
# include <time.h>
# include <assert.h>
# include <unistd.h>
# include <sys/time.h>
/*
* There happens to be linuxes which read siginfo.h when including
* signal.h, which, for no appearent reason, defines these symbols.
*/
# ifdef POLL_IN
# undef POLL_IN
# endif
# ifdef POLL_OUT
# undef POLL_OUT
# endif
# include "rpoll.h"
/*
# define DEBUG
*/
# ifdef USE_POLL
# ifdef NEED_POLL_XOPEN_TWIDDLE
# define __USE_XOPEN
# endif
# include <poll.h>
# ifdef NEED_POLL_XOPEN_TWIDDLE
# undef __USE_XOPEN
# endif
# include <stropts.h>
# endif
/*
* the second define is for Linux, which sometimes fails to
* declare INFTIM.
*/
# if defined(USE_SELECT) || !defined(INFTIM)
# define INFTIM (-1)
# endif
# if defined(SIGPOLL)
# define SIGNAL SIGPOLL
# else
# if defined(SIGIO)
# define SIGNAL SIGIO
# endif
# endif
# ifdef USE_POLL
# define poll_in (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI)
# define poll_out (POLLOUT | POLLWRNORM | POLLWRBAND)
# define poll_except (POLLERR | POLLHUP)
# endif
# ifdef BROKEN_SELECT_PROTO
# define SELECT_CAST(P) (int *)P
# else
# define SELECT_CAST(P) P
# endif
typedef signed long long tval_t;
static inline tval_t GETMSECS(void);
static inline tval_t
GETMSECS(void) {
struct timeval tval;
(void)gettimeofday(&tval, NULL);
return (tval_t)tval.tv_sec*1000+tval.tv_usec/1000;
}
/*
* Simple fatal exit.
*/
static void
_panic(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
fprintf(stderr, "panic: ");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
va_end(ap);
exit(1);
}
static void *
_xrealloc(void *p, size_t s)
{
void *ptr;
if(p == NULL) {
if((ptr=malloc(s)) == NULL && (s!=0 || (ptr=malloc(1)) == NULL))
_panic("out of memory: xrealloc(%lx, %lu)",
(unsigned long)p, (unsigned long)s);
} else if(s == 0) {
free(p);
if((ptr=malloc(s)) == NULL && (ptr=malloc(1)) == NULL)
_panic("out of memory: xrealloc(%lx, %lu)",
(unsigned long)p, (unsigned long)s);
} else {
if((ptr = realloc(p, s)) == NULL)
_panic("out of memory: xrealloc(%lx, %lu)",
(unsigned long)p, (unsigned long)s);
}
return ptr;
}
/*
* This structure holds one registration record for files
*/
typedef struct {
int fd; /* file descriptor (-1 if struct unused) */
int mask; /* event flags */
void * arg; /* client arg */
poll_f func; /* handler */
# ifdef USE_POLL
struct pollfd *pfd; /* pointer to corresponding poll() structure */
# endif
} PollReg_t;
/*
* Now for timers
*/
typedef struct {
u_int msecs; /* millisecond value of the timer */
int repeat; /* one shot or repeat? */
void *arg; /* client arg */
timer_f func; /* handler, 0 means disfunct */
tval_t when; /* next time to trigger in msecs! */
} PollTim_t;
/* how many records should our table grow at once? */
# define POLL_REG_GROW 100
# ifdef USE_POLL
static struct pollfd * pfd; /* fd list for poll() */
# endif
# ifdef USE_SELECT
static fd_set rset, wset, xset; /* file descriptor sets for select() */
static int maxfd; /* maximum fd number */
# endif
static int in_dispatch;
static PollReg_t * regs; /* registration records */
static u_int regs_alloc; /* how many are allocated */
static u_int regs_used; /* upper used limit */
static sigset_t bset; /* blocked signals */
static int rebuild; /* rebuild table on next dispatch() */
static int * tfd; /* sorted entries */
static u_int tfd_alloc; /* number of entries allocated */
static u_int tfd_used; /* number of entries used */
static PollTim_t * tims; /* timer registration records */
static u_int tims_alloc; /* how many are allocated */
static u_int tims_used; /* how many are used */
static int resort; /* resort on next dispatch */
int rpoll_trace;
int rpoll_policy; /* if 0 start sched callbacks from 0 else try round robin */
static void poll_build(void);
static void poll_blocksig(void);
static void poll_unblocksig(void);
static void sort_timers(void);
/*
* Private function to block SIGPOLL or SIGIO for a short time.
* Don't forget to call poll_unblock before return from the calling function.
* Don't change the mask between this calls (your changes will be lost).
*/
static void
poll_blocksig(void)
{
sigset_t set;
sigemptyset(&set);
sigaddset(&set, SIGNAL);
if(sigprocmask(SIG_BLOCK, &set, &bset))
_panic("sigprocmask(SIG_BLOCK): %s", strerror(errno));
}
/*
* unblock the previously blocked signal
*/
static void
poll_unblocksig(void)
{
if(sigprocmask(SIG_SETMASK, &bset, NULL))
_panic("sigprocmask(SIG_SETMASK): %s", strerror(errno));
}
/*
* Register the file descriptor fd. If the event corresponding to
* mask arrives func is called with arg.
* If fd is already registered with that func and arg, only the mask
* is changed.
* We block the IO-signal, so the dispatch function can be called from
* within the signal handler.
*/
int
poll_register(int fd, poll_f func, void *arg, int mask)
{
PollReg_t * p;
poll_blocksig();
/* already registered? */
for(p = regs; p < &regs[regs_alloc]; p++)
if(p->fd == fd && p->func == func && p->arg == arg) {
p->mask = mask;
break;
}
if(p == &regs[regs_alloc]) {
/* no - register */
/* find a free slot */
for(p = regs; p < &regs[regs_alloc]; p++)
if(p->fd == -1)
break;
if(p == &regs[regs_alloc]) {
size_t newsize = regs_alloc + POLL_REG_GROW;
regs = _xrealloc(regs, sizeof(regs[0]) * newsize);
for(p = &regs[regs_alloc]; p < &regs[newsize]; p++) {
p->fd = -1;
# ifdef USE_POLL
p->pfd = NULL;
# endif
}
p = &regs[regs_alloc];
regs_alloc = newsize;
}
p->fd = fd;
p->arg = arg;
p->mask = mask;
p->func = func;
regs_used++;
rebuild = 1;
}
poll_unblocksig();
if(rpoll_trace)
fprintf(stderr, "poll_register(%d, %#lx, %#lx, %#x)->%d",
fd, (u_long)func, (u_long)arg, mask, p - regs);
return p - regs;
}
/*
* remove registration
*/
void
poll_unregister(int handle)
{
if(rpoll_trace)
fprintf(stderr, "poll_unregister(%d)", handle);
poll_blocksig();
regs[handle].fd = -1;
# ifdef USE_POLL
regs[handle].pfd = NULL;
# endif
rebuild = 1;
regs_used--;
poll_unblocksig();
}
/*
* Build the structures used by poll() or select()
*/
static void
poll_build(void)
{
PollReg_t * p;
# ifdef USE_POLL
struct pollfd * f;
f = pfd = _xrealloc(pfd, sizeof(pfd[0]) * regs_used);
for(p = regs; p < &regs[regs_alloc]; p++)
if(p->fd >= 0) {
f->fd = p->fd;
f->events = 0;
if(p->mask & POLL_IN)
f->events |= poll_in;
if(p->mask & POLL_OUT)
f->events |= poll_out;
if(p->mask & POLL_EXCEPT)
f->events |= poll_except;
f->revents = 0;
p->pfd = f++;
}
assert(f == &pfd[regs_used]);
# endif
# ifdef USE_SELECT
FD_ZERO(&rset);
FD_ZERO(&wset);
FD_ZERO(&xset);
maxfd = -1;
for(p = regs; p < &regs[regs_alloc]; p++)
if(p->fd >= 0) {
if(p->fd > maxfd)
maxfd = p->fd;
if(p->mask & POLL_IN)
FD_SET(p->fd, &rset);
if(p->mask & POLL_OUT)
FD_SET(p->fd, &wset);
if(p->mask & POLL_EXCEPT)
FD_SET(p->fd, &xset);
}
# endif
}
int
poll_start_timer(u_int msecs, int repeat, timer_f func, void *arg)
{
PollTim_t *p;
/* find unused entry */
for(p = tims; p < &tims[tims_alloc]; p++)
if(p->func == NULL)
break;
if(p == &tims[tims_alloc]) {
if(tims_alloc == tims_used) {
size_t newsize = tims_alloc + POLL_REG_GROW;
tims = _xrealloc(tims, sizeof(tims[0]) * newsize);
for(p = &tims[tims_alloc]; p < &tims[newsize]; p++)
p->func = NULL;
p = &tims[tims_alloc];
tims_alloc = newsize;
}
}
/* create entry */
p->msecs = msecs;
p->repeat = repeat;
p->arg = arg;
p->func = func;
p->when = GETMSECS() + msecs;
tims_used++;
resort = 1;
if(rpoll_trace)
fprintf(stderr, "poll_start_timer(%u, %d, %#lx, %#lx)->%u",
msecs, repeat, (u_long)func, (u_long)arg, p - tims);
return p - tims;
}
/*
* Here we have to look into the sorted table, whether any entry there points
* into the registration table for the deleted entry. This is needed,
* because a unregistration can occure while we are scanning through the
* table in dispatch(). Do this only, if we are really there - resorting
* will sort out things if we are called from outside the loop.
*/
void
poll_stop_timer(int handle)
{
u_int i;
if(rpoll_trace)
fprintf(stderr, "poll_stop_timer(%d)", handle);
tims[handle].func = NULL;
tims_used--;
resort = 1;
if(!in_dispatch)
return;
for(i = 0; i < tfd_used; i++)
if(tfd[i] == handle) {
tfd[i] = -1;
break;
}
}
/*
* Squeeze and sort timer table.
* Should perhaps use a custom sort.
*/
static int
tim_cmp(const void *p1, const void *p2)
{
int t1 = *(const int *)p1;
int t2 = *(const int *)p2;
return tims[t1].when < tims[t2].when ? -1
: tims[t1].when > tims[t2].when ? +1
: 0;
}
/*
* Reconstruct the tfd-array. This will be an sorted array of indexes
* to the used entries in tims. The next timer to expire will be infront
* of the array. tfd_used is the number of used entries. The array is
* re-allocated if needed.
*/
static void
sort_timers(void)
{
int *pp;
u_int i;
if(tims_used > tfd_alloc) {
tfd_alloc = tims_used;
tfd = _xrealloc(tfd, sizeof(int *) * tfd_alloc);
}
pp = tfd;
for(i = 0; i < tims_alloc; i++)
if(tims[i].func)
*pp++ = i;
assert(pp - tfd == (ptrdiff_t)tims_used);
tfd_used = tims_used;
if(tfd_used > 1)
qsort(tfd, tfd_used, sizeof(int), tim_cmp);
}
/*
* Poll the file descriptors and dispatch to the right function
* If wait is true the poll blocks until somewhat happens.
* Don't use a pointer here, because the called function may cause
* a reallocation! The check for pfd != NULL is required, because
* a sequence of unregister/register could make the wrong callback
* to be called. So we clear pfd in unregister and check here.
*/
void
poll_dispatch(int wait)
{
u_int i, idx;
int ret;
tval_t now;
int tout;
static u_int last_index;
# ifdef USE_SELECT
fd_set nrset, nwset, nxset;
struct timeval tv;
# endif
in_dispatch = 1;
if(rebuild) {
rebuild = 0;
poll_build();
}
if(resort) {
resort = 0;
sort_timers();
}
/* in wait mode - compute the timeout */
if(wait) {
if(tfd_used) {
now = GETMSECS();
# ifdef DEBUG
{
fprintf(stderr, "now=%"QUADFMT"u", now);
for(i = 0; i < tims_used; i++)
fprintf(stderr, "timers[%2d] = %"QUADFMT"d", i, tfd[i]->when - now);
}
# endif
if((tout = tims[tfd[0]].when - now) < 0)
tout = 0;
} else
tout = INFTIM;
} else
tout = 0;
# ifdef DEBUG
fprintf(stderr, "rpoll -- selecting with tout=%u", tout);
# endif
# ifdef USE_POLL
ret = poll(pfd, regs_used, tout);
# endif
# ifdef USE_SELECT
nrset = rset;
nwset = wset;
nxset = xset;
if(tout != INFTIM) {
tv.tv_sec = tout / 1000;
tv.tv_usec = (tout % 1000) * 1000;
}
ret = select(maxfd+1,
SELECT_CAST(&nrset),
SELECT_CAST(&nwset),
SELECT_CAST(&nxset), (tout==INFTIM) ? 0 : &tv);
# endif
if(ret == -1) {
if(errno == EINTR)
return;
_panic("poll/select: %s", strerror(errno));
}
/* dispatch files */
if(ret > 0) {
for(i = 0; i < regs_alloc; i++) {
idx = rpoll_policy ? ((last_index+i) % regs_alloc) : i;
assert(idx < regs_alloc);
if(regs[idx].fd >= 0) {
int mask = 0;
# ifdef USE_POLL
if(regs[idx].pfd) {
if(regs[idx].pfd->revents & poll_in)
mask |= POLL_IN;
if(regs[idx].pfd->revents & poll_out)
mask |= POLL_OUT;
if(regs[idx].pfd->revents & poll_except)
mask |= POLL_EXCEPT;
}
# endif
# ifdef USE_SELECT
if(FD_ISSET(regs[idx].fd, &nrset))
mask |= POLL_IN;
if(FD_ISSET(regs[idx].fd, &nwset))
mask |= POLL_OUT;
if(FD_ISSET(regs[idx].fd, &nxset))
mask |= POLL_EXCEPT;
# endif
assert(idx < regs_alloc);
if(mask) {
if(rpoll_trace)
fprintf(stderr, "poll_dispatch() -- "
"file %d/%d",
regs[idx].fd, idx);
(*regs[idx].func)(regs[idx].fd, mask, regs[idx].arg);
}
}
}
last_index++;
}
/* dispatch timeouts */
if(tfd_used) {
now = GETMSECS();
for(i = 0; i < tfd_used; i++) {
if(tfd[i] < 0)
continue;
if(tims[tfd[i]].when > now)
break;
if(rpoll_trace)
fprintf(stderr, "rpoll_dispatch() -- timeout %d",tfd[i]);
(*tims[tfd[i]].func)(tfd[i], tims[tfd[i]].arg);
if(tfd[i] < 0)
continue;
if(tims[tfd[i]].repeat)
tims[tfd[i]].when = now + tims[tfd[i]].msecs;
else {
tims[tfd[i]].func = NULL;
tims_used--;
tfd[i] = -1;
}
resort = 1;
}
}
in_dispatch = 0;
}
# ifdef TESTME
struct timeval start, now;
int t0, t1;
double elaps(void);
void infunc(int fd, int mask, void *arg);
double
elaps(void)
{
gettimeofday(&now, NULL);
return (double)(10 * now.tv_sec + now.tv_usec / 100000 - 10 * start.tv_sec - start.tv_usec / 100000)
/ 10;
}
void
infunc(int fd, int mask, void *arg)
{
char buf[1024];
int ret;
mask = mask;
arg = arg;
if((ret = read(fd, buf, sizeof(buf))) < 0)
_panic("read: %s", strerror(errno));
write(1, "stdin:", 6);
write(1, buf, ret);
}
void tfunc0(int tid, void *arg);
void tfunc1(int tid, void *arg);
void
tfunc0(int tid, void *arg)
{
printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg);
}
void
tfunc1(int tid, void *arg)
{
printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg);
}
void first(int tid, void *arg);
void second(int tid, void *arg);
void
second(int tid, void *arg)
{
printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg);
poll_start_timer(5500, 0, first, "first");
poll_stop_timer(t1);
t0 = poll_start_timer(1000, 1, tfunc0, "1 second");
}
void
first(int tid, void *arg)
{
printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg);
poll_start_timer(3700, 0, second, "second");
poll_stop_timer(t0);
t1 = poll_start_timer(250, 1, tfunc1, "1/4 second");
}
int
main(int argc, char *argv[])
{
argc = argc;
argv = argv;
gettimeofday(&start, NULL);
poll_register(0, infunc, NULL, POLL_IN);
t0 = poll_start_timer(1000, 1, tfunc0, "1 second");
poll_start_timer(2500, 0, first, "first");
while(1)
poll_dispatch(1);
return 0;
}
# endif