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/*
* FD polling functions for generic select()
*
* Copyright 2000-2014 Willy Tarreau <w@1wt.eu>
*
* 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.
*
*/
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <common/compat.h>
#include <common/config.h>
#include <common/ticks.h>
#include <common/time.h>
#include <types/global.h>
#include <proto/fd.h>
/* private data */
static fd_set *fd_evts[2];
static THREAD_LOCAL fd_set *tmp_evts[2];
/* Immediately remove the entry upon close() */
REGPRM1 static void __fd_clo(int fd)
{
SPIN_LOCK(POLL_LOCK, &poll_lock);
FD_CLR(fd, fd_evts[DIR_RD]);
FD_CLR(fd, fd_evts[DIR_WR]);
SPIN_UNLOCK(POLL_LOCK, &poll_lock);
}
/*
* Select() poller
*/
REGPRM2 static void _do_poll(struct poller *p, int exp)
{
int status;
int fd, i;
struct timeval delta;
int delta_ms;
int fds;
int updt_idx, en, eo;
char count;
int readnotnull, writenotnull;
/* first, scan the update list to find changes */
for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
fd = fd_updt[updt_idx];
if (!fdtab[fd].owner)
continue;
SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fdtab[fd].updated = 0;
fdtab[fd].new = 0;
eo = fdtab[fd].state;
en = fd_compute_new_polled_status(eo);
fdtab[fd].state = en;
SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
if ((eo ^ en) & FD_EV_POLLED_RW) {
/* poll status changed, update the lists */
SPIN_LOCK(POLL_LOCK, &poll_lock);
if ((eo & ~en) & FD_EV_POLLED_R)
FD_CLR(fd, fd_evts[DIR_RD]);
else if ((en & ~eo) & FD_EV_POLLED_R)
FD_SET(fd, fd_evts[DIR_RD]);
if ((eo & ~en) & FD_EV_POLLED_W)
FD_CLR(fd, fd_evts[DIR_WR]);
else if ((en & ~eo) & FD_EV_POLLED_W)
FD_SET(fd, fd_evts[DIR_WR]);
SPIN_UNLOCK(POLL_LOCK, &poll_lock);
}
}
fd_nbupdt = 0;
/* let's restore fdset state */
readnotnull = 0; writenotnull = 0;
for (i = 0; i < (maxfd + FD_SETSIZE - 1)/(8*sizeof(int)); i++) {
readnotnull |= (*(((int*)tmp_evts[DIR_RD])+i) = *(((int*)fd_evts[DIR_RD])+i)) != 0;
writenotnull |= (*(((int*)tmp_evts[DIR_WR])+i) = *(((int*)fd_evts[DIR_WR])+i)) != 0;
}
#if 0
/* just a verification code, needs to be removed for performance */
for (i=0; i<maxfd; i++) {
if (FD_ISSET(i, tmp_evts[DIR_RD]) != FD_ISSET(i, fd_evts[DIR_RD]))
abort();
if (FD_ISSET(i, tmp_evts[DIR_WR]) != FD_ISSET(i, fd_evts[DIR_WR]))
abort();
}
#endif
delta_ms = 0;
delta.tv_sec = 0;
delta.tv_usec = 0;
if (!exp) {
delta_ms = MAX_DELAY_MS;
delta.tv_sec = (MAX_DELAY_MS / 1000);
delta.tv_usec = (MAX_DELAY_MS % 1000) * 1000;
}
else if (!tick_is_expired(exp, now_ms)) {
delta_ms = TICKS_TO_MS(tick_remain(now_ms, exp)) + SCHEDULER_RESOLUTION;
if (delta_ms > MAX_DELAY_MS)
delta_ms = MAX_DELAY_MS;
delta.tv_sec = (delta_ms / 1000);
delta.tv_usec = (delta_ms % 1000) * 1000;
}
gettimeofday(&before_poll, NULL);
status = select(maxfd,
readnotnull ? tmp_evts[DIR_RD] : NULL,
writenotnull ? tmp_evts[DIR_WR] : NULL,
NULL,
&delta);
tv_update_date(delta_ms, status);
measure_idle();
if (status <= 0)
return;
for (fds = 0; (fds * BITS_PER_INT) < maxfd; fds++) {
if ((((int *)(tmp_evts[DIR_RD]))[fds] | ((int *)(tmp_evts[DIR_WR]))[fds]) == 0)
continue;
for (count = BITS_PER_INT, fd = fds * BITS_PER_INT; count && fd < maxfd; count--, fd++) {
unsigned int n = 0;
/* if we specify read first, the accepts and zero reads will be
* seen first. Moreover, system buffers will be flushed faster.
*/
if (!fdtab[fd].owner || !(fdtab[fd].thread_mask & tid_bit))
continue;
if (FD_ISSET(fd, tmp_evts[DIR_RD]))
n |= FD_POLL_IN;
if (FD_ISSET(fd, tmp_evts[DIR_WR]))
n |= FD_POLL_OUT;
fd_update_events(fd, n);
}
}
}
static int init_select_per_thread()
{
int fd_set_bytes;
fd_set_bytes = sizeof(fd_set) * (global.maxsock + FD_SETSIZE - 1) / FD_SETSIZE;
if ((tmp_evts[DIR_RD] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
goto fail;
if ((tmp_evts[DIR_WR] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
goto fail;
return 1;
fail:
free(tmp_evts[DIR_RD]);
free(tmp_evts[DIR_WR]);
return 0;
}
static void deinit_select_per_thread()
{
free(tmp_evts[DIR_WR]); tmp_evts[DIR_WR] = NULL;
free(tmp_evts[DIR_RD]); tmp_evts[DIR_RD] = NULL;
}
/*
* Initialization of the select() poller.
* Returns 0 in case of failure, non-zero in case of success. If it fails, it
* disables the poller by setting its pref to 0.
*/
REGPRM1 static int _do_init(struct poller *p)
{
__label__ fail_swevt, fail_srevt, fail_revt;
int fd_set_bytes;
p->private = NULL;
if (global.maxsock > FD_SETSIZE)
goto fail_revt;
fd_set_bytes = sizeof(fd_set) * (global.maxsock + FD_SETSIZE - 1) / FD_SETSIZE;
if ((fd_evts[DIR_RD] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
goto fail_srevt;
if ((fd_evts[DIR_WR] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
goto fail_swevt;
hap_register_per_thread_init(init_select_per_thread);
hap_register_per_thread_deinit(deinit_select_per_thread);
return 1;
fail_swevt:
free(fd_evts[DIR_RD]);
fail_srevt:
free(tmp_evts[DIR_WR]);
free(tmp_evts[DIR_RD]);
fail_revt:
p->pref = 0;
return 0;
}
/*
* Termination of the select() poller.
* Memory is released and the poller is marked as unselectable.
*/
REGPRM1 static void _do_term(struct poller *p)
{
free(fd_evts[DIR_WR]);
free(fd_evts[DIR_RD]);
p->private = NULL;
p->pref = 0;
}
/*
* Check that the poller works.
* Returns 1 if OK, otherwise 0.
*/
REGPRM1 static int _do_test(struct poller *p)
{
if (global.maxsock > FD_SETSIZE)
return 0;
return 1;
}
/*
* It is a constructor, which means that it will automatically be called before
* main(). This is GCC-specific but it works at least since 2.95.
* Special care must be taken so that it does not need any uninitialized data.
*/
__attribute__((constructor))
static void _do_register(void)
{
struct poller *p;
if (nbpollers >= MAX_POLLERS)
return;
p = &pollers[nbpollers++];
p->name = "select";
p->pref = 150;
p->flags = 0;
p->private = NULL;
p->clo = __fd_clo;
p->test = _do_test;
p->init = _do_init;
p->term = _do_term;
p->poll = _do_poll;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/