posix-poll.c File Reference

#include "uv.h"
#include "internal.h"
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <errno.h>
#include <unistd.h>

Go to the source code of this file.

Functions
int	uv__platform_loop_init (uv_loop_t *loop)
void	uv__platform_loop_delete (uv_loop_t *loop)
int	uv__io_fork (uv_loop_t *loop)
static void	uv__pollfds_maybe_resize (uv_loop_t *loop)
static void	uv__pollfds_swap (uv_loop_t *loop, size_t l, size_t r)
static void	uv__pollfds_add (uv_loop_t *loop, uv__io_t *w)
static void	uv__pollfds_del (uv_loop_t *loop, int fd)
void	uv__io_poll (uv_loop_t *loop, int timeout)
void	uv__platform_invalidate_fd (uv_loop_t *loop, int fd)
int	uv__io_check_fd (uv_loop_t *loop, int fd)

Function Documentation

uv__io_check_fd()

int uv__io_check_fd	(	uv_loop_t *	loop,
		int	fd
	)

Definition at line 356 of file posix-poll.c.

                                             {
  struct pollfd p[1];
  int rv;
 
  p[0].fd = fd;
  p[0].events = POLLIN;
 
  do
    rv = poll(p, 1, 0);
  while (rv == -1 && (errno == EINTR || errno == EAGAIN));
 
  if (rv == -1)
    return UV__ERR(errno);
 
  if (p[0].revents & POLLNVAL)
    return UV_EINVAL;
 
  return 0;
}

References EAGAIN, EINTR, fd, p, poll, and UV__ERR.

uv__io_fork()

int uv__io_fork

(

uv_loop_t *

loop

)

Definition at line 49 of file posix-poll.c.

                                 {
  uv__platform_loop_delete(loop);
  return uv__platform_loop_init(loop);
}

References loop, uv__platform_loop_delete(), and uv__platform_loop_init().

uv__io_poll()

void uv__io_poll	(	uv_loop_t *	loop,
		int	timeout
	)

Definition at line 134 of file posix-poll.c.

                                               {
  sigset_t* pset;
  sigset_t set;
  uint64_t time_base;
  uint64_t time_diff;
  QUEUE* q;
  uv__io_t* w;
  size_t i;
  unsigned int nevents;
  int nfds;
  int have_signals;
  struct pollfd* pe;
  int fd;
  int user_timeout;
  int reset_timeout;
 
  if (loop->nfds == 0) {
    assert(QUEUE_EMPTY(&loop->watcher_queue));
    return;
  }
 
  /* Take queued watchers and add their fds to our poll fds array.  */
  while (!QUEUE_EMPTY(&loop->watcher_queue)) {
    q = QUEUE_HEAD(&loop->watcher_queue);
    QUEUE_REMOVE(q);
    QUEUE_INIT(q);
 
    w = QUEUE_DATA(q, uv__io_t, watcher_queue);
    assert(w->pevents != 0);
    assert(w->fd >= 0);
    assert(w->fd < (int) loop->nwatchers);
 
    uv__pollfds_add(loop, w);
 
    w->events = w->pevents;
  }
 
  /* Prepare a set of signals to block around poll(), if any.  */
  pset = NULL;
  if (loop->flags & UV_LOOP_BLOCK_SIGPROF) {
    pset = &set;
    sigemptyset(pset);
    sigaddset(pset, SIGPROF);
  }
 
  assert(timeout >= -1);
  time_base = loop->time;
 
  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
    reset_timeout = 1;
    user_timeout = timeout;
    timeout = 0;
  } else {
    reset_timeout = 0;
  }
 
  /* Loop calls to poll() and processing of results.  If we get some
   * results from poll() but they turn out not to be interesting to
   * our caller then we need to loop around and poll() again.
   */
  for (;;) {
    /* Only need to set the provider_entry_time if timeout != 0. The function
     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
     */
    if (timeout != 0)
      uv__metrics_set_provider_entry_time(loop);
 
    if (pset != NULL)
      if (pthread_sigmask(SIG_BLOCK, pset, NULL))
        abort();
    nfds = poll(loop->poll_fds, (nfds_t)loop->poll_fds_used, timeout);
    if (pset != NULL)
      if (pthread_sigmask(SIG_UNBLOCK, pset, NULL))
        abort();
 
    /* Update loop->time unconditionally. It's tempting to skip the update when
     * timeout == 0 (i.e. non-blocking poll) but there is no guarantee that the
     * operating system didn't reschedule our process while in the syscall.
     */
    SAVE_ERRNO(uv__update_time(loop));
 
    if (nfds == 0) {
      if (reset_timeout != 0) {
        timeout = user_timeout;
        reset_timeout = 0;
        if (timeout == -1)
          continue;
        if (timeout > 0)
          goto update_timeout;
      }
 
      assert(timeout != -1);
      return;
    }
 
    if (nfds == -1) {
      if (errno != EINTR)
        abort();
 
      if (reset_timeout != 0) {
        timeout = user_timeout;
        reset_timeout = 0;
      }
 
      if (timeout == -1)
        continue;
 
      if (timeout == 0)
        return;
 
      /* Interrupted by a signal. Update timeout and poll again. */
      goto update_timeout;
    }
 
    /* Tell uv__platform_invalidate_fd not to manipulate our array
     * while we are iterating over it.
     */
    loop->poll_fds_iterating = 1;
 
    /* Initialize a count of events that we care about.  */
    nevents = 0;
    have_signals = 0;
 
    /* Loop over the entire poll fds array looking for returned events.  */
    for (i = 0; i < loop->poll_fds_used; i++) {
      pe = loop->poll_fds + i;
      fd = pe->fd;
 
      /* Skip invalidated events, see uv__platform_invalidate_fd.  */
      if (fd == -1)
        continue;
 
      assert(fd >= 0);
      assert((unsigned) fd < loop->nwatchers);
 
      w = loop->watchers[fd];
 
      if (w == NULL) {
        /* File descriptor that we've stopped watching, ignore.  */
        uv__platform_invalidate_fd(loop, fd);
        continue;
      }
 
      /* Filter out events that user has not requested us to watch
       * (e.g. POLLNVAL).
       */
      pe->revents &= w->pevents | POLLERR | POLLHUP;
 
      if (pe->revents != 0) {
        /* Run signal watchers last.  */
        if (w == &loop->signal_io_watcher) {
          have_signals = 1;
        } else {
          uv__metrics_update_idle_time(loop);
          w->cb(loop, w, pe->revents);
        }
 
        nevents++;
      }
    }
 
    if (reset_timeout != 0) {
      timeout = user_timeout;
      reset_timeout = 0;
    }
 
    if (have_signals != 0) {
      uv__metrics_update_idle_time(loop);
      loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN);
    }
 
    loop->poll_fds_iterating = 0;
 
    /* Purge invalidated fds from our poll fds array.  */
    uv__pollfds_del(loop, -1);
 
    if (have_signals != 0)
      return;  /* Event loop should cycle now so don't poll again. */
 
    if (nevents != 0)
      return;
 
    if (timeout == 0)
      return;
 
    if (timeout == -1)
      continue;
 
update_timeout:
    assert(timeout > 0);
 
    time_diff = loop->time - time_base;
    if (time_diff >= (uint64_t) timeout)
      return;
 
    timeout -= time_diff;
  }
}

References assert(), EINTR, fd, flags, i, loop, nfds, NULL, poll, QUEUE_DATA, QUEUE_EMPTY, QUEUE_HEAD, QUEUE_INIT, QUEUE_REMOVE, SAVE_ERRNO, timeout, uv__get_internal_fields, uv__metrics_set_provider_entry_time(), uv__metrics_update_idle_time(), uv__platform_invalidate_fd(), uv__pollfds_add(), uv__pollfds_del(), UV_LOOP_BLOCK_SIGPROF, UV_METRICS_IDLE_TIME, and w.

uv__platform_invalidate_fd()

void uv__platform_invalidate_fd	(	uv_loop_t *	loop,
		int	fd
	)

Definition at line 336 of file posix-poll.c.

                                                         {
  size_t i;
 
  assert(fd >= 0);
 
  if (loop->poll_fds_iterating) {
    /* uv__io_poll is currently iterating.  Just invalidate fd.  */
    for (i = 0; i < loop->poll_fds_used; i++)
      if (loop->poll_fds[i].fd == fd) {
        loop->poll_fds[i].fd = -1;
        loop->poll_fds[i].events = 0;
        loop->poll_fds[i].revents = 0;
      }
  } else {
    /* uv__io_poll is not iterating.  Delete fd from the set.  */
    uv__pollfds_del(loop, fd);
  }
}

References assert(), fd, i, loop, and uv__pollfds_del().

Referenced by uv__io_poll().

uv__platform_loop_delete()

void uv__platform_loop_delete

(

uv_loop_t *

loop

)

Definition at line 44 of file posix-poll.c.

                                               {
  uv__free(loop->poll_fds);
  loop->poll_fds = NULL;
}

References loop, NULL, and uv__free().

Referenced by uv__io_fork().

uv__platform_loop_init()

int uv__platform_loop_init

(

uv_loop_t *

loop

)

Definition at line 36 of file posix-poll.c.

                                            {
  loop->poll_fds = NULL;
  loop->poll_fds_used = 0;
  loop->poll_fds_size = 0;
  loop->poll_fds_iterating = 0;
  return 0;
}

References loop, and NULL.

Referenced by uv__io_fork().

uv__pollfds_add()

static void uv__pollfds_add ( uv_loop_t *  loop, uv__io_t *  w  )

static

Definition at line 86 of file posix-poll.c.

                                                          {
  size_t i;
  struct pollfd* pe;
 
  /* If the fd is already in the set just update its events.  */
  assert(!loop->poll_fds_iterating);
  for (i = 0; i < loop->poll_fds_used; ++i) {
    if (loop->poll_fds[i].fd == w->fd) {
      loop->poll_fds[i].events = w->pevents;
      return;
    }
  }
 
  /* Otherwise, allocate a new slot in the set for the fd.  */
  uv__pollfds_maybe_resize(loop);
  pe = &loop->poll_fds[loop->poll_fds_used++];
  pe->fd = w->fd;
  pe->events = w->pevents;
}

References assert(), i, loop, uv__pollfds_maybe_resize(), and w.

Referenced by uv__io_poll().

uv__pollfds_del()

static void uv__pollfds_del ( uv_loop_t *  loop, int  fd  )

static

Definition at line 107 of file posix-poll.c.

                                                     {
  size_t i;
  assert(!loop->poll_fds_iterating);
  for (i = 0; i < loop->poll_fds_used;) {
    if (loop->poll_fds[i].fd == fd) {
      /* swap to last position and remove */
      --loop->poll_fds_used;
      uv__pollfds_swap(loop, i, loop->poll_fds_used);
      loop->poll_fds[loop->poll_fds_used].fd = -1;
      loop->poll_fds[loop->poll_fds_used].events = 0;
      loop->poll_fds[loop->poll_fds_used].revents = 0;
      /* This method is called with an fd of -1 to purge the invalidated fds,
       * so we may possibly have multiples to remove.
       */
      if (-1 != fd)
        return;
    } else {
      /* We must only increment the loop counter when the fds do not match.
       * Otherwise, when we are purging an invalidated fd, the value just
       * swapped here from the previous end of the array will be skipped.
       */
       ++i;
    }
  }
}

References assert(), fd, i, loop, and uv__pollfds_swap().

Referenced by uv__io_poll(), and uv__platform_invalidate_fd().

uv__pollfds_maybe_resize()

static void uv__pollfds_maybe_resize ( uv_loop_t *  loop )

static

Definition at line 55 of file posix-poll.c.

                                                      {
  size_t i;
  size_t n;
  struct pollfd* p;
 
  if (loop->poll_fds_used < loop->poll_fds_size)
    return;
 
  n = loop->poll_fds_size ? loop->poll_fds_size * 2 : 64;
  p = uv__reallocf(loop->poll_fds, n * sizeof(*loop->poll_fds));
  if (p == NULL)
    abort();
 
  loop->poll_fds = p;
  for (i = loop->poll_fds_size; i < n; i++) {
    loop->poll_fds[i].fd = -1;
    loop->poll_fds[i].events = 0;
    loop->poll_fds[i].revents = 0;
  }
  loop->poll_fds_size = n;
}

References i, loop, n, NULL, p, and uv__reallocf().

Referenced by uv__pollfds_add().

uv__pollfds_swap()

static void uv__pollfds_swap ( uv_loop_t *  loop, size_t  l, size_t  r  )

static

Definition at line 78 of file posix-poll.c.

                                                                  {
  struct pollfd pfd;
  pfd = loop->poll_fds[l];
  loop->poll_fds[l] = loop->poll_fds[r];
  loop->poll_fds[r] = pfd;
}

References loop, and r.

Referenced by uv__pollfds_del().