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b2715bbc5e
the FdSource was calling g_cancellable_disconnect while holding the main context lock, which is bad news if the ::cancelled handler is trying to get that lock to wake up the mainloop... Bug 586432
143 lines
3.7 KiB
C
143 lines
3.7 KiB
C
/* GIO - GLib Input, Output and Streaming Library
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*
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* Copyright (C) 2006-2007 Red Hat, Inc.
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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; either
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* version 2 of the License, or (at your option) any later version.
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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
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* Public License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Author: Alexander Larsson <alexl@redhat.com>
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*/
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#include "config.h"
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#include "gasynchelper.h"
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/**
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* SECTION:gasynchelper
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* @short_description: Asynchronous Helper Functions
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* @include: gio/gio.h
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* @see_also: #GAsyncReady
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*
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* Provides helper functions for asynchronous operations.
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*
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**/
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/*************************************************************************
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* fd source *
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************************************************************************/
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typedef struct
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{
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GSource source;
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GPollFD pollfd;
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GCancellable *cancellable;
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gulong cancelled_tag;
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} FDSource;
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static gboolean
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fd_source_prepare (GSource *source,
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gint *timeout)
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{
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FDSource *fd_source = (FDSource *)source;
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*timeout = -1;
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return g_cancellable_is_cancelled (fd_source->cancellable);
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}
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static gboolean
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fd_source_check (GSource *source)
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{
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FDSource *fd_source = (FDSource *)source;
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return
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g_cancellable_is_cancelled (fd_source->cancellable) ||
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fd_source->pollfd.revents != 0;
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}
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static gboolean
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fd_source_dispatch (GSource *source,
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GSourceFunc callback,
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gpointer user_data)
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{
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GFDSourceFunc func = (GFDSourceFunc)callback;
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FDSource *fd_source = (FDSource *)source;
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g_warn_if_fail (func != NULL);
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return (*func) (user_data, fd_source->pollfd.revents, fd_source->pollfd.fd);
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}
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static void
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fd_source_finalize (GSource *source)
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{
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FDSource *fd_source = (FDSource *)source;
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/* we don't use g_cancellable_disconnect() here, since we are holding
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* the main context lock here, and the ::disconnect signal handler
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* will try to grab that, and deadlock looms.
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*/
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if (fd_source->cancelled_tag)
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g_signal_handler_disconnect (fd_source->cancellable,
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fd_source->cancelled_tag);
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if (fd_source->cancellable)
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g_object_unref (fd_source->cancellable);
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}
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static GSourceFuncs fd_source_funcs = {
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fd_source_prepare,
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fd_source_check,
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fd_source_dispatch,
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fd_source_finalize
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};
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/* Might be called on another thread */
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static void
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fd_source_cancelled_cb (GCancellable *cancellable,
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gpointer data)
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{
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/* Wake up the mainloop in case we're waiting on async calls with FDSource */
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g_main_context_wakeup (NULL);
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}
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GSource *
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_g_fd_source_new (int fd,
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gushort events,
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GCancellable *cancellable)
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{
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GSource *source;
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FDSource *fd_source;
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source = g_source_new (&fd_source_funcs, sizeof (FDSource));
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fd_source = (FDSource *)source;
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if (cancellable)
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fd_source->cancellable = g_object_ref (cancellable);
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fd_source->pollfd.fd = fd;
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fd_source->pollfd.events = events;
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g_source_add_poll (source, &fd_source->pollfd);
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if (cancellable)
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fd_source->cancelled_tag =
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g_cancellable_connect (cancellable,
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(GCallback)fd_source_cancelled_cb,
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NULL, NULL);
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return source;
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}
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