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/* vim:ts=8:sts=8:sw=4:noai:noexpandtab
*
* Re-entrant safe signal handling.
*
* Copyright (c) 2006-2010 Miru Limited.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*/
#define _GNU_SOURCE
#include <fcntl.h>
#include <signal.h> /* _GNU_SOURCE for strsignal() */
#include <glib.h>
#ifndef G_OS_WIN32
# include <unistd.h>
#else
# include <io.h>
#endif
#include <pgm/pgm.h>
#include "pgm/signal.h"
//#define SIGNAL_DEBUG
/* globals */
static pgm_sighandler_t signal_list[NSIG];
static int signal_pipe[2];
static GIOChannel* signal_io = NULL;
static void on_signal (int);
static gboolean on_io_signal (GIOChannel*, GIOCondition, gpointer);
static const char* cond_string (GIOCondition);
static
void
set_nonblock (
const int s,
const gboolean v
)
{
#ifndef G_OS_WIN32
int flags = fcntl (s, F_GETFL);
if (!v) flags &= ~O_NONBLOCK;
else flags |= O_NONBLOCK;
fcntl (s, F_SETFL, flags);
#else
u_long mode = v;
ioctlsocket (s, FIONBIO, &mode);
#endif
}
/* install signal handler and return unix fd to add to event loop
*/
gboolean
pgm_signal_install (
int signum,
pgm_sighandler_t handler,
gpointer user_data
)
{
g_debug ("pgm_signal_install (signum:%d handler:%p user_data:%p)",
signum, (const void*)handler, user_data);
if (NULL == signal_io)
{
#ifdef G_OS_UNIX
if (pipe (signal_pipe))
#else
if (_pipe (signal_pipe, 4096, _O_BINARY | _O_NOINHERIT))
#endif
return FALSE;
set_nonblock (signal_pipe[0], TRUE);
set_nonblock (signal_pipe[1], TRUE);
/* add to evm */
signal_io = g_io_channel_unix_new (signal_pipe[0]);
g_io_add_watch (signal_io, G_IO_IN, on_io_signal, user_data);
}
signal_list[signum] = handler;
return (SIG_ERR != signal (signum, on_signal));
}
/* process signal from operating system
*/
static
void
on_signal (
int signum
)
{
g_debug ("on_signal (signum:%d)", signum);
if (write (signal_pipe[1], &signum, sizeof(signum)) != sizeof(signum))
{
#ifndef G_OS_WIN32
g_warning ("Unix signal %s (%d) lost", strsignal (signum), signum);
#else
g_warning ("Unix signal (%d) lost", signum);
#endif
}
}
/* process signal from pipe
*/
static
gboolean
on_io_signal (
GIOChannel* source,
GIOCondition cond,
gpointer user_data
)
{
/* pre-conditions */
g_assert (NULL != source);
g_assert (G_IO_IN == cond);
g_debug ("on_io_signal (source:%p cond:%s user_data:%p)",
(gpointer)source, cond_string (cond), user_data);
int signum;
const gsize bytes_read = read (g_io_channel_unix_get_fd (source), &signum, sizeof(signum));
if (sizeof(signum) == bytes_read)
{
signal_list[signum] (signum, user_data);
}
else
{
g_warning ("Lost data in signal pipe, read %" G_GSIZE_FORMAT " byte%s expected %" G_GSIZE_FORMAT ".",
bytes_read, bytes_read > 1 ? "s" : "", sizeof(signum));
}
return TRUE;
}
static
const char*
cond_string (
GIOCondition cond
)
{
const char* c;
switch (cond) {
case G_IO_IN: c = "G_IO_IN"; break;
case G_IO_OUT: c = "G_IO_OUT"; break;
case G_IO_PRI: c = "G_IO_PRI"; break;
case G_IO_ERR: c = "G_IO_ERR"; break;
case G_IO_HUP: c = "G_IO_HUP"; break;
case G_IO_NVAL: c = "G_IO_NVAL"; break;
default: c = "(unknown)"; break;
}
return c;
}
/* eof */
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