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/*
* Copyright (c) 2007 Brian Tarricone <bjt23@cornell.edu>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SIGNAL_H
#include <signal.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <glib.h>
#include <libxfce4util/libxfce4util.h>
#include <libxfce4util/libxfce4util-alias.h>
#define SIGNAL_PIPE_READ __signal_pipe[0]
#define SIGNAL_PIPE_WRITE __signal_pipe[1]
typedef struct
{
gint signal;
XfcePosixSignalHandler handler;
gpointer user_data;
struct sigaction old_sa;
} XfcePosixSignalHandlerData;
static gboolean __inited = FALSE;
static int __signal_pipe[2] = { -1, -1 };
static GHashTable *__handlers = NULL;
static GIOChannel *__signal_io = NULL;
static guint __io_watch_id = 0;
static void
xfce_posix_signal_handler_data_free(XfcePosixSignalHandlerData *hdata)
{
if(!hdata)
return;
sigaction(hdata->signal, &hdata->old_sa, NULL);
g_free(hdata);
}
static gboolean
xfce_posix_signal_handler_pipe_io(GIOChannel *source,
GIOCondition condition,
gpointer data)
{
int signal = 0;
GError *error = NULL;
gsize bin = 0;
XfcePosixSignalHandlerData *hdata;
if(G_IO_STATUS_NORMAL == g_io_channel_read_chars(source, (gchar *)&signal,
sizeof(signal), &bin,
&error)
&& bin == sizeof(signal))
{
hdata = g_hash_table_lookup(__handlers, GINT_TO_POINTER(signal));
if(hdata)
hdata->handler(signal, hdata->user_data);
} else {
if(error) {
g_critical("Signal pipe read failed: %s\n", error->message);
g_error_free(error);
} else {
g_critical("Short read from signal pipe (expected %d, got %d)\n",
(int)sizeof(signal), (int)bin);
}
}
return TRUE;
}
static void
xfce_posix_signal_handler(int signal)
{
write(SIGNAL_PIPE_WRITE, &signal, sizeof(signal));
}
/**
* xfce_posix_signal_handler_init:
* @error: Location of a #GError to store any possible errors.
*
* Initializes the POSIX signal handler system. Must be called
* before setting any POSIX signal handlers.
*
* Returns: %TRUE on success, %FALSE on failure, in which case
* @error will be set.
**/
gboolean
xfce_posix_signal_handler_init(GError **error)
{
if(G_UNLIKELY(__inited))
return TRUE;
if(pipe(__signal_pipe)) {
if(error) {
g_set_error(error, G_FILE_ERROR, g_file_error_from_errno(errno),
_("pipe() failed: %s"), strerror(errno));
}
return FALSE;
}
__handlers = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,
(GDestroyNotify)xfce_posix_signal_handler_data_free);
__signal_io = g_io_channel_unix_new(SIGNAL_PIPE_READ);
g_io_channel_set_close_on_unref(__signal_io, FALSE);
g_io_channel_set_encoding(__signal_io, NULL, NULL);
g_io_channel_set_buffered(__signal_io, FALSE);
__io_watch_id = g_io_add_watch(__signal_io, G_IO_IN,
xfce_posix_signal_handler_pipe_io, NULL);
__inited = TRUE;
return TRUE;
}
/**
* xfce_posix_signal_handler_shutdown:
*
* Frees all memory associated with the POSIX signal handling system
* and restores all default signal handlers.
**/
void
xfce_posix_signal_handler_shutdown()
{
if(G_UNLIKELY(!__inited))
return;
g_source_remove(__io_watch_id);
__io_watch_id = 0;
g_io_channel_unref(__signal_io);
__signal_io = NULL;
g_hash_table_destroy(__handlers);
__handlers = NULL;
close(SIGNAL_PIPE_READ);
SIGNAL_PIPE_READ = -1;
close(SIGNAL_PIPE_WRITE);
SIGNAL_PIPE_WRITE = -1;
__inited = FALSE;
}
/**
* xfce_posix_signal_handler_set_handler:
* @signal: A POSIX signal id number.
* @handler: A callback function.
* @user_data: Arbitrary data that will be passed to @handler.
* @error: Location of a #GError to store any possible errors.
*
* Sets @handler to be called whenever @signal is caught by the
* application. The @user_data parameter will be passed as an argument
* to @handler.
*
* Returns: %TRUE on success, %FALSE otherwise, in which case
* @error will be set.
**/
gboolean
xfce_posix_signal_handler_set_handler(gint signal,
XfcePosixSignalHandler handler,
gpointer user_data,
GError **error)
{
XfcePosixSignalHandlerData *hdata;
struct sigaction sa;
if(G_UNLIKELY(!__inited)) {
if(error) {
g_set_error(error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
_("xfce_posix_signal_handler_init() must be called first"));
}
return FALSE;
}
if(!handler) {
g_warning("NULL signal handler supplied; removing existing handler");
xfce_posix_signal_handler_restore_handler(signal);
return TRUE;
}
if(g_hash_table_lookup(__handlers, GINT_TO_POINTER(signal)))
xfce_posix_signal_handler_restore_handler(signal);
hdata = g_new0(XfcePosixSignalHandlerData, 1);
hdata->signal = signal;
hdata->handler = handler;
hdata->user_data = user_data;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = xfce_posix_signal_handler;
sa.sa_flags = SA_RESTART;
if(sigaction(signal, &sa, &hdata->old_sa)) {
if(error) {
g_set_error(error, G_FILE_ERROR, g_file_error_from_errno(errno),
_("sigaction() failed: %s\n"), strerror(errno));
}
g_free(hdata);
return FALSE;
}
g_hash_table_insert(__handlers, GINT_TO_POINTER(signal), hdata);
return TRUE;
}
/**
* xfce_posix_signal_handler_restore_handler:
* @signal: A POSIX signal id number.
*
* Restores the default handler for @signal.
**/
void
xfce_posix_signal_handler_restore_handler(gint signal)
{
if(G_UNLIKELY(!__inited))
return;
g_hash_table_remove(__handlers, GINT_TO_POINTER(signal));
}
#define __XFCE_POSIX_SIGNAL_HANDLER_C__
#include <libxfce4util/libxfce4util-aliasdef.c>
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