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https://github.com/warmcat/libwebsockets.git
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17357ddd5a
From eventfd man page: Applications can use an eventfd file descriptor instead of a pipe (see pipe(2)) in all cases where a pipe is used simply to signal events. The kernel overhead of an eventfd file descriptor is much lower than that of a pipe, and only one file descriptor is required (versus the two required for a pipe).
70 lines
1.9 KiB
C
70 lines
1.9 KiB
C
/*
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* libwebsockets - small server side websockets and web server implementation
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*
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* Copyright (C) 2010-2018 Andy Green <andy@warmcat.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation:
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* version 2.1 of the License.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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#define _GNU_SOURCE
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#include "core/private.h"
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int
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lws_plat_pipe_create(struct lws *wsi)
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{
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struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
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#if defined(LWS_HAVE_EVENTFD)
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pt->dummy_pipe_fds[0] = eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK);
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pt->dummy_pipe_fds[1] = -1;
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return pt->dummy_pipe_fds[0]<0?-1:0;
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#elif defined(LWS_HAVE_PIPE2)
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return pipe2(pt->dummy_pipe_fds, O_NONBLOCK);
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#else
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return pipe(pt->dummy_pipe_fds);
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#endif
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}
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int
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lws_plat_pipe_signal(struct lws *wsi)
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{
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struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
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#if defined(LWS_HAVE_EVENTFD)
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eventfd_t value = 1;
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return eventfd_write(pt->dummy_pipe_fds[0], value);
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#else
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char buf = 0;
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int n;
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n = write(pt->dummy_pipe_fds[1], &buf, 1);
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return n != 1;
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#endif
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}
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void
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lws_plat_pipe_close(struct lws *wsi)
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{
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struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
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if (pt->dummy_pipe_fds[0] && pt->dummy_pipe_fds[0] != -1)
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close(pt->dummy_pipe_fds[0]);
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if (pt->dummy_pipe_fds[1] && pt->dummy_pipe_fds[1] != -1)
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close(pt->dummy_pipe_fds[1]);
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pt->dummy_pipe_fds[0] = pt->dummy_pipe_fds[1] = -1;
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}
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