src/common/fd-tracker/utils-epoll.c

   1 /*
   2  * Copyright (C) 2018 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #include <common/compat/poll.h>
  19
  20 #include "utils.h"
  21
  22 struct create_args {
  23         struct lttng_poll_event *events;
  24         int size;
  25         int flags;
  26 };
  27
  28 static int open_epoll(void *data, int *out_fd)
  29 {
  30         int ret;
  31         struct create_args *args = data;
  32
  33         ret = lttng_poll_create(args->events, args->size, args->flags);
  34         if (ret < 0) {
  35                 goto end;
  36         }
  37
  38         *out_fd = args->events->epfd;
  39 end:
  40         return ret;
  41 }
  42
  43 static int close_epoll(void *data, int *in_fd)
  44 {
  45         /* Will close the epfd. */
  46         lttng_poll_clean((struct lttng_poll_event *) data);
  47         return 0;
  48 }
  49
  50 /*
  51  * The epoll variant of the poll compat layer creates an unsuspendable fd which
  52  * must be tracked.
  53  */
  54 int fd_tracker_util_poll_create(struct fd_tracker *tracker,
  55                 const char *name,
  56                 struct lttng_poll_event *events,
  57                 int size,
  58                 int flags)
  59 {
  60         int out_fd;
  61         struct create_args create_args = {
  62                 .events = events,
  63                 .size = size,
  64                 .flags = flags,
  65         };
  66
  67         return fd_tracker_open_unsuspendable_fd(
  68                         tracker, &out_fd, &name, 1, open_epoll, &create_args);
  69 }
  70
  71 int fd_tracker_util_poll_clean(
  72                 struct fd_tracker *tracker, struct lttng_poll_event *events)
  73 {
  74         return fd_tracker_close_unsuspendable_fd(
  75                         tracker, &events->epfd, 1, close_epoll, events);
  76 }