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ev_poll.c

/*
 * FD polling functions for generic poll()
 *
 * Copyright 2000-2007 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/poll.h>
#include <sys/time.h>
#include <sys/types.h>

#include <common/compat.h>
#include <common/config.h>
#include <common/time.h>

#include <types/fd.h>
#include <types/global.h>

#include <proto/fd.h>
#include <proto/task.h>


static fd_set *fd_evts[2];

/* private data */
static struct pollfd *poll_events = NULL;


/*
 * Benchmarks performed on a Pentium-M notebook show that using functions
 * instead of the usual macros improve the FD_* performance by about 80%,
 * and that marking them regparm(2) adds another 20%.
 */
REGPRM2 static int __fd_is_set(const int fd, int dir)
{
      return FD_ISSET(fd, fd_evts[dir]);
}

REGPRM2 static int __fd_set(const int fd, int dir)
{
      FD_SET(fd, fd_evts[dir]);
      return 0;
}

REGPRM2 static int __fd_clr(const int fd, int dir)
{
      FD_CLR(fd, fd_evts[dir]);
      return 0;
}

REGPRM2 static int __fd_cond_s(const int fd, int dir)
{
      int ret;
      ret = !FD_ISSET(fd, fd_evts[dir]);
      if (ret)
            FD_SET(fd, fd_evts[dir]);
      return ret;
}

REGPRM2 static int __fd_cond_c(const int fd, int dir)
{
      int ret;
      ret = FD_ISSET(fd, fd_evts[dir]);
      if (ret)
            FD_CLR(fd, fd_evts[dir]);
      return ret;
}

REGPRM1 static void __fd_rem(const int fd)
{
      FD_CLR(fd, fd_evts[DIR_RD]);
      FD_CLR(fd, fd_evts[DIR_WR]);
}

/*
 * Poll() poller
 */
REGPRM2 static void _do_poll(struct poller *p, struct timeval *exp)
{
      int status;
      int fd, nbfd;
      int wait_time;

      int fds, count;
      int sr, sw;
      unsigned rn, wn; /* read new, write new */

      nbfd = 0;
      for (fds = 0; (fds << INTBITS) < maxfd; fds++) {

            rn = ((int*)fd_evts[DIR_RD])[fds];
            wn = ((int*)fd_evts[DIR_WR])[fds];
        
            if ((rn|wn)) {
                  for (count = 0, fd = fds << INTBITS; count < (1<<INTBITS) && fd < maxfd; count++, fd++) {
#define FDSETS_ARE_INT_ALIGNED
#ifdef FDSETS_ARE_INT_ALIGNED

#define WE_REALLY_NOW_THAT_FDSETS_ARE_INTS
#ifdef WE_REALLY_NOW_THAT_FDSETS_ARE_INTS
                        sr = (rn >> count) & 1;
                        sw = (wn >> count) & 1;
#else
                        sr = FD_ISSET(fd&((1<<INTBITS)-1), (typeof(fd_set*))&rn);
                        sw = FD_ISSET(fd&((1<<INTBITS)-1), (typeof(fd_set*))&wn);
#endif
#else
                        sr = FD_ISSET(fd, fd_evts[DIR_RD]);
                        sw = FD_ISSET(fd, fd_evts[DIR_WR]);
#endif
                        if ((sr|sw)) {
                              poll_events[nbfd].fd = fd;
                              poll_events[nbfd].events = (sr ? POLLIN : 0) | (sw ? POLLOUT : 0);
                              nbfd++;
                        }
                  }
            }             
      }
      
      /* now let's wait for events */
      if (tv_iseternity(exp))
            wait_time = -1;
      else if (tv_isge(&now, exp))
            wait_time = 0;
      else
            wait_time = __tv_ms_elapsed(&now, exp) + 1;

      status = poll(poll_events, nbfd, wait_time);
      tv_now(&now);

      for (count = 0; status > 0 && count < nbfd; count++) {
            fd = poll_events[count].fd;
        
            if (!(poll_events[count].revents & ( POLLOUT | POLLIN | POLLERR | POLLHUP )))
                  continue;

            /* ok, we found one active fd */
            status--;

            if (FD_ISSET(fd, fd_evts[DIR_RD])) {
                  if (fdtab[fd].state == FD_STCLOSE)
                        continue;
                  if (poll_events[count].revents & ( POLLIN | POLLERR | POLLHUP ))
                        fdtab[fd].cb[DIR_RD].f(fd);
            }
        
            if (FD_ISSET(fd, fd_evts[DIR_WR])) {
                  if (fdtab[fd].state == FD_STCLOSE)
                        continue;
                  if (poll_events[count].revents & ( POLLOUT | POLLERR | POLLHUP ))
                        fdtab[fd].cb[DIR_WR].f(fd);
            }
      }

}

/*
 * Initialization of the poll() 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_pe;
      int fd_set_bytes;

      p->private = NULL;
      fd_set_bytes = sizeof(fd_set) * (global.maxsock + FD_SETSIZE - 1) / FD_SETSIZE;

      poll_events = (struct pollfd*)
            calloc(1, sizeof(struct pollfd) * global.maxsock);

      if (poll_events == NULL)
            goto fail_pe;
            
      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;

      return 1;

 fail_swevt:
      free(fd_evts[DIR_RD]);
 fail_srevt:
      free(poll_events);
 fail_pe:
      p->pref = 0;
      return 0;
}

/*
 * Termination of the poll() poller.
 * Memory is released and the poller is marked as unselectable.
 */
REGPRM1 static void _do_term(struct poller *p)
{
      if (fd_evts[DIR_WR])
            free(fd_evts[DIR_WR]);
      if (fd_evts[DIR_RD])
            free(fd_evts[DIR_RD]);
      if (poll_events)
            free(poll_events);
      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)
{
      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 = "poll";
      p->pref = 200;
      p->private = NULL;

      p->test = _do_test;
      p->init = _do_init;
      p->term = _do_term;
      p->poll = _do_poll;
      p->is_set = __fd_is_set;
      p->set = __fd_set;
      p->clr = __fd_clr;
      p->clo = p->rem = __fd_rem;
      p->cond_s = __fd_cond_s;
      p->cond_c = __fd_cond_c;
}


/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */

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