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Member "libev-4.33/ev_port.c" (31 Oct 2019, 6528 Bytes) of package /linux/misc/libev-4.33.tar.gz:


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    1 /*
    2  * libev solaris event port backend
    3  *
    4  * Copyright (c) 2007,2008,2009,2010,2011,2019 Marc Alexander Lehmann <libev@schmorp.de>
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without modifica-
    8  * tion, are permitted provided that the following conditions are met:
    9  *
   10  *   1.  Redistributions of source code must retain the above copyright notice,
   11  *       this list of conditions and the following disclaimer.
   12  *
   13  *   2.  Redistributions in binary form must reproduce the above copyright
   14  *       notice, this list of conditions and the following disclaimer in the
   15  *       documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
   18  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
   19  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
   20  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
   21  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   22  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   23  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   24  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
   25  * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   26  * OF THE POSSIBILITY OF SUCH DAMAGE.
   27  *
   28  * Alternatively, the contents of this file may be used under the terms of
   29  * the GNU General Public License ("GPL") version 2 or any later version,
   30  * in which case the provisions of the GPL are applicable instead of
   31  * the above. If you wish to allow the use of your version of this file
   32  * only under the terms of the GPL and not to allow others to use your
   33  * version of this file under the BSD license, indicate your decision
   34  * by deleting the provisions above and replace them with the notice
   35  * and other provisions required by the GPL. If you do not delete the
   36  * provisions above, a recipient may use your version of this file under
   37  * either the BSD or the GPL.
   38  */
   39 
   40 /* useful reading:
   41  *
   42  * http://bugs.opensolaris.org/view_bug.do?bug_id=6268715 (random results)
   43  * http://bugs.opensolaris.org/view_bug.do?bug_id=6455223 (just totally broken)
   44  * http://bugs.opensolaris.org/view_bug.do?bug_id=6873782 (manpage ETIME)
   45  * http://bugs.opensolaris.org/view_bug.do?bug_id=6874410 (implementation ETIME)
   46  * http://www.mail-archive.com/networking-discuss@opensolaris.org/msg11898.html ETIME vs. nget
   47  * http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/lib/libc/port/gen/event_port.c (libc)
   48  * http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/portfs/port.c#1325 (kernel)
   49  */
   50 
   51 #include <sys/types.h>
   52 #include <sys/time.h>
   53 #include <poll.h>
   54 #include <port.h>
   55 #include <string.h>
   56 #include <errno.h>
   57 
   58 inline_speed
   59 void
   60 port_associate_and_check (EV_P_ int fd, int ev)
   61 {
   62   if (0 >
   63       port_associate (
   64          backend_fd, PORT_SOURCE_FD, fd,
   65          (ev & EV_READ ? POLLIN : 0)
   66          | (ev & EV_WRITE ? POLLOUT : 0),
   67          0
   68       )
   69   )
   70     {
   71       if (errno == EBADFD)
   72         {
   73           assert (("libev: port_associate found invalid fd", errno != EBADFD));
   74           fd_kill (EV_A_ fd);
   75         }
   76       else
   77         ev_syserr ("(libev) port_associate");
   78     }
   79 }
   80 
   81 static void
   82 port_modify (EV_P_ int fd, int oev, int nev)
   83 {
   84   /* we need to reassociate no matter what, as closes are
   85    * once more silently being discarded.
   86    */
   87   if (!nev)
   88     {
   89       if (oev)
   90         port_dissociate (backend_fd, PORT_SOURCE_FD, fd);
   91     }
   92   else
   93     port_associate_and_check (EV_A_ fd, nev);
   94 }
   95 
   96 static void
   97 port_poll (EV_P_ ev_tstamp timeout)
   98 {
   99   int res, i;
  100   struct timespec ts;
  101   uint_t nget = 1;
  102 
  103   /* we initialise this to something we will skip in the loop, as */
  104   /* port_getn can return with nget unchanged, but no indication */
  105   /* whether it was the original value or has been updated :/ */
  106   port_events [0].portev_source = 0;
  107 
  108   EV_RELEASE_CB;
  109   EV_TS_SET (ts, timeout);
  110   res = port_getn (backend_fd, port_events, port_eventmax, &nget, &ts);
  111   EV_ACQUIRE_CB;
  112 
  113   /* port_getn may or may not set nget on error */
  114   /* so we rely on port_events [0].portev_source not being updated */
  115   if (res == -1 && errno != ETIME && errno != EINTR)
  116     ev_syserr ("(libev) port_getn (see http://bugs.opensolaris.org/view_bug.do?bug_id=6268715, try LIBEV_FLAGS=3 env variable)");
  117 
  118   for (i = 0; i < nget; ++i)
  119     {
  120       if (port_events [i].portev_source == PORT_SOURCE_FD)
  121         {
  122           int fd = port_events [i].portev_object;
  123 
  124           fd_event (
  125             EV_A_
  126             fd,
  127             (port_events [i].portev_events & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
  128             | (port_events [i].portev_events & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
  129           );
  130 
  131           fd_change (EV_A_ fd, EV__IOFDSET);
  132         }
  133     }
  134 
  135   if (ecb_expect_false (nget == port_eventmax))
  136     {
  137       ev_free (port_events);
  138       port_eventmax = array_nextsize (sizeof (port_event_t), port_eventmax, port_eventmax + 1);
  139       port_events = (port_event_t *)ev_malloc (sizeof (port_event_t) * port_eventmax);
  140     }
  141 }
  142 
  143 inline_size
  144 int
  145 port_init (EV_P_ int flags)
  146 {
  147   /* Initialize the kernel queue */
  148   if ((backend_fd = port_create ()) < 0)
  149     return 0;
  150 
  151   assert (("libev: PORT_SOURCE_FD must not be zero", PORT_SOURCE_FD));
  152 
  153   fcntl (backend_fd, F_SETFD, FD_CLOEXEC); /* not sure if necessary, hopefully doesn't hurt */
  154 
  155   /* if my reading of the opensolaris kernel sources are correct, then
  156    * opensolaris does something very stupid: it checks if the time has already
  157    * elapsed and doesn't round up if that is the case, otherwise it DOES round
  158    * up. Since we can't know what the case is, we need to guess by using a
  159    * "large enough" timeout. Normally, 1e-9 would be correct.
  160    */
  161   backend_mintime = EV_TS_CONST (1e-3); /* needed to compensate for port_getn returning early */
  162   backend_modify  = port_modify;
  163   backend_poll    = port_poll;
  164 
  165   port_eventmax = 64; /* initial number of events receivable per poll */
  166   port_events = (port_event_t *)ev_malloc (sizeof (port_event_t) * port_eventmax);
  167 
  168   return EVBACKEND_PORT;
  169 }
  170 
  171 inline_size
  172 void
  173 port_destroy (EV_P)
  174 {
  175   ev_free (port_events);
  176 }
  177 
  178 inline_size
  179 void
  180 port_fork (EV_P)
  181 {
  182   close (backend_fd);
  183 
  184   while ((backend_fd = port_create ()) < 0)
  185     ev_syserr ("(libev) port");
  186 
  187   fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
  188 
  189   /* re-register interest in fds */
  190   fd_rearm_all (EV_A);
  191 }
  192