When transferring 500 downloads in parallel with a c-ares enabled build only

to find that it crashed miserably, and this was due to some select()isms left
in the code. This was due to API restrictions in c-ares 1.3.x, but with the
upcoming c-ares 1.4.0 this is no longer the case so now libcurl runs much
better with c-ares and the multi interface with > 1024 file descriptors in
use.

1 files changed, 0 insertions, 221 deletions

diff --git a/lib/select.c b/lib/select.c
index daa591eae..28bb141b1 100644
--- a/lib/select.c
+++ b/lib/select.c
@@ -482,227 +482,6 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
   return r;
 }
 
-/*
- * This is a wrapper around select().  It uses poll() when a fine
- * poll() is available, in order to avoid limits with FD_SETSIZE,
- * otherwise select() is used.  An error is returned if select() is
- * being used and a the number of file descriptors is larger than
- * FD_SETSIZE.  A NULL timeout pointer makes this function wait
- * indefinitely, unles no valid file descriptor is given, when this
- * happens the NULL timeout is ignored and the function times out
- * immediately.  When compiled with CURL_ACKNOWLEDGE_EINTR defined,
- * EINTR condition is honored and function might exit early without
- * awaiting timeout, otherwise EINTR will be ignored.
- *
- * Return values:
- *   -1 = system call error or nfds > FD_SETSIZE
- *    0 = timeout
- *    N = number of file descriptors kept in file descriptor sets.
- */
-int Curl_select(int nfds,
-                fd_set *fds_read, fd_set *fds_write, fd_set *fds_excep,
-                struct timeval *timeout)
-{
-  struct timeval initial_tv;
-  int timeout_ms;
-  int pending_ms = 0;
-  int error;
-  int r;
-#ifdef HAVE_POLL_FINE
-  struct pollfd small_fds[SMALL_POLLNFDS];
-  struct pollfd *poll_fds;
-  int ix;
-  int fd;
-  int poll_nfds = 0;
-#else
-  struct timeval pending_tv;
-  struct timeval *ptimeout;
-#endif
-  int ret = 0;
-
-  if ((nfds < 0) ||
-     ((nfds > 0) && (!fds_read && !fds_write && !fds_excep))) {
-    SET_SOCKERRNO(EINVAL);
-    return -1;
-  }
-
-  if (timeout) {
-    if ((timeout->tv_sec < 0) ||
-        (timeout->tv_usec < 0) ||
-        (timeout->tv_usec >= 1000000)) {
-      SET_SOCKERRNO(EINVAL);
-      return -1;
-    }
-    timeout_ms = (int)(timeout->tv_sec * 1000) +
-      (int)(timeout->tv_usec / 1000);
-  }
-  else {
-    timeout_ms = -1;
-  }
-
-  if ((!nfds) || (!fds_read && !fds_write && !fds_excep)) {
-    r = wait_ms(timeout_ms);
-    return r;
-  }
-
-  /* Avoid initial timestamp, avoid gettimeofday() call, when elapsed
-     time in this function does not need to be measured. This happens
-     when function is called with a zero timeout in the timeval struct
-     referenced argument or when a NULL pointer is received as timeval
-     reference indicating a blocking call should be performed. */
-
-  if (timeout_ms > 0) {
-    pending_ms = timeout_ms;
-    initial_tv = curlx_tvnow();
-  }
-
-#ifdef HAVE_POLL_FINE
-
-  if (fds_read || fds_write || fds_excep) {
-    fd = nfds;
-    while (fd--) {
-      if ((fds_read && (0 != FD_ISSET(fd, fds_read))) ||
-          (fds_write && (0 != FD_ISSET(fd, fds_write))) ||
-          (fds_excep && (0 != FD_ISSET(fd, fds_excep))))
-        poll_nfds++;
-    }
-  }
-
-  if (!poll_nfds)
-    poll_fds = NULL;
-  else if (poll_nfds <= SMALL_POLLNFDS)
-    poll_fds = small_fds;
-  else {
-    poll_fds = malloc(poll_nfds * sizeof(struct pollfd));
-    if (!poll_fds) {
-      SET_SOCKERRNO(ENOBUFS);
-      return -1;
-    }
-  }
-
-  if (poll_fds) {
-    int events;
-    ix = 0;
-    fd = nfds;
-    while (fd--) {
-      events = 0;
-      if (fds_read && (0 != FD_ISSET(fd, fds_read)))
-        events |= (POLLRDNORM|POLLIN);
-      if (fds_write && (0 != FD_ISSET(fd, fds_write)))
-        events |= (POLLWRNORM|POLLOUT);
-      if (fds_excep && (0 != FD_ISSET(fd, fds_excep)))
-        events |= (POLLRDBAND|POLLPRI);
-      if (events) {
-        poll_fds[ix].events = events;
-        poll_fds[ix].fd = fd;
-        poll_fds[ix].revents = 0;
-        ix++;
-        if(ix == poll_nfds)
-          /* since we know this is the total amount of descriptors with
-             interesting actions, we can skip the rest of the loop at this
-             point */
-          break;
-      }
-    }
-  }
-
-  do {
-    if (timeout_ms < 0)
-      pending_ms = -1;
-    else if (!timeout_ms)
-      pending_ms = 0;
-    r = poll(poll_fds, poll_nfds, pending_ms);
-    if (r != -1)
-      break;
-    error = SOCKERRNO;
-    if ((error == EINVAL) || error_is_EINTR)
-      break;
-    if (timeout_ms > 0) {
-      pending_ms = timeout_ms - elapsed_ms;
-      if (pending_ms <= 0)
-        break;
-    }
-  } while (r == -1);
-
-  if (r < 0)
-    ret = -1;
-
-  if (r > 0) {
-    ix = poll_nfds;
-    while (ix--) {
-      if (poll_fds[ix].revents & POLLNVAL) {
-        SET_SOCKERRNO(EBADF);
-        ret = -1;
-        break;
-      }
-    }
-  }
-
-  if (!ret) {
-    ix = poll_nfds;
-    while (ix--) {
-      if (fds_read && (0 != FD_ISSET(poll_fds[ix].fd, fds_read))) {
-        if (0 == (poll_fds[ix].revents & (POLLRDNORM|POLLERR|POLLHUP|POLLIN)))
-          FD_CLR(poll_fds[ix].fd, fds_read);
-        else
-          ret++;
-      }
-      if (fds_write && (0 != FD_ISSET(poll_fds[ix].fd, fds_write))) {
-        if (0 == (poll_fds[ix].revents & (POLLWRNORM|POLLERR|POLLHUP|POLLOUT)))
-          FD_CLR(poll_fds[ix].fd, fds_write);
-        else
-          ret++;
-      }
-      if (fds_excep && (0 != FD_ISSET(poll_fds[ix].fd, fds_excep))) {
-        if (0 == (poll_fds[ix].revents & (POLLRDBAND|POLLERR|POLLHUP|POLLPRI)))
-          FD_CLR(poll_fds[ix].fd, fds_excep);
-        else
-          ret++;
-      }
-    }
-  }
-
-  if (poll_fds && (poll_nfds > SMALL_POLLNFDS))
-    free(poll_fds);
-
-#else  /* HAVE_POLL_FINE */
-
-  VERIFY_NFDS(nfds);
-
-  ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
-
-  do {
-    if (timeout_ms > 0) {
-      pending_tv.tv_sec = pending_ms / 1000;
-      pending_tv.tv_usec = (pending_ms % 1000) * 1000;
-    }
-    else if (!timeout_ms) {
-      pending_tv.tv_sec = 0;
-      pending_tv.tv_usec = 0;
-    }
-    r = select(nfds, fds_read, fds_write, fds_excep, ptimeout);
-    if (r != -1)
-      break;
-    error = SOCKERRNO;
-    if ((error == EINVAL) || (error == EBADF) || error_is_EINTR)
-      break;
-    if (timeout_ms > 0) {
-      pending_ms = timeout_ms - elapsed_ms;
-      if (pending_ms <= 0)
-        break;
-    }
-  } while (r == -1);
-
-  if (r < 0)
-    ret = -1;
-  else
-    ret = r;
-
-#endif  /* HAVE_POLL_FINE */
-
-  return ret;
-}
-
 #ifdef TPF
 /*
  * This is a replacement for select() on the TPF platform.