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# sig.c

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    00001 /*
    00002  * $Id: sig.c,v 1.6 2003/12/01 09:10:16 troth Exp $
    00003  *
    00004  ****************************************************************************
    00005  *
    00006  * simulavr - A simulator for the Atmel AVR family of microcontrollers.
    00007  * Copyright (C) 2001, 2002, 2003  Theodore A. Roth
    00008  *
    00009  * This program is free software; you can redistribute it and/or modify
    00010  * it under the terms of the GNU General Public License as published by
    00011  * the Free Software Foundation; either version 2 of the License, or
    00012  * (at your option) any later version.
    00013  *
    00014  * This program is distributed in the hope that it will be useful,
    00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00017  * GNU General Public License for more details.
    00018  *
    00019  * You should have received a copy of the GNU General Public License
    00020  * along with this program; if not, write to the Free Software
    00021  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    00022  *
    00023  ****************************************************************************
    00024  */
    00025
    00026 /**
    00027  * \file sig.c
    00028  * \brief Public interface to signal handlers.
    00029  *
    00030  * This module provides a way for the simulator to process signals generated
    00031  * by the native host system. Note that these signals in this context have
    00032  * nothing to do with signals or interrupts as far as a program running in the
    00033  * simulator is concerned. */
    00034
    00035 #include <config.h>
    00036
    00037 #include <stdio.h>
    00038 #include <stdlib.h>
    00039 #include <string.h>
    00040 #include <errno.h>
    00041 #include <signal.h>
    00042
    00043 #include "avrerror.h"
    00044 #include "sig.h"
    00045
    00046 static volatile int global_got_sigint = 0;
    00047
    00048 /*
    00049  * Private.
    00050  *
    00051  * Handler for SIGINT signals.
    00052  */
    00053 static void
    00054 signal_handle_sigint (int signo)
    00055 {
    00056     global_got_sigint = 1;
    00057 }
    00058
    00059 /**
    00060  * \brief Start watching for the occurrance of the given signal.
    00061  *
    00062  * This function will install a signal handler which will set a flag when the
    00063  * signal occurs. Once the watch has been started, periodically call
    00064  * signal_has_occurred() to check if the signal was raised.
    00065  */
    00066 void
    00067 signal_watch_start (int signo)
    00068 {
    00069     struct sigaction act, oact;
    00070
    00071     sigemptyset (&act.sa_mask);
    00072     act.sa_flags = 0;
    00073
    00074     switch (signo)
    00075     {
    00076         case SIGINT:
    00077             global_got_sigint = 0;
    00078             act.sa_handler = signal_handle_sigint;
    00079             break;
    00080         default:
    00081             avr_warning ("Invalid signal: %d\n", signo);
    00082             return;
    00083     }
    00084
    00085     if (sigaction (signo, &act, &oact) < 0)
    00086         avr_warning ("Failed to install signal handler: sig=%d: %s\n", signo,
    00087                      strerror (errno));
    00088 }
    00089
    00090 /**
    00091  * \brief Stop watching signal.
    00092  *
    00093  * Restores the default signal handler for the given signal and resets the
    00094  * signal flag.
    00095  */
    00096 void
    00097 signal_watch_stop (int signo)
    00098 {
    00099     struct sigaction act, oact;
    00100
    00101     sigemptyset (&act.sa_mask);
    00102     act.sa_flags = 0;
    00103     act.sa_handler = SIG_DFL;
    00104
    00105     signal_reset (signo);
    00106
    00107     if (sigaction (signo, &act, &oact) < 0)
    00108         avr_warning ("Failed to restore default signal handler: sig=%d: %s\n",
    00109                      signo, strerror (errno));
    00110 }
    00111
    00112 /**
    00113  * \brief Check to see if a signal has occurred.
    00114  *
    00115  * \return Non-zero if signal has occurred. The flag will always be reset
    00116  * automatically.
    00117  */
    00118 int
    00119 signal_has_occurred (int signo)
    00120 {
    00121     int res = 0;
    00122
    00123     switch (signo)
    00124     {
    00125         case SIGINT:
    00126             res = global_got_sigint;
    00127             global_got_sigint = 0;
    00128             break;
    00129         default:
    00130             avr_warning ("Invalid signal: %d", signo);
    00131     }
    00132
    00133     return res;
    00134 }
    00135
    00136 /**
    00137  * \brief Clear the flag which indicates that a signal has ocurred.
    00138  *
    00139  * Use signal_reset to manually reset (i.e. clear) the flag.
    00140  */
    00141 void
    00142 signal_reset (int signo)
    00143 {
    00144     signal_has_occurred (signo);
    00145 }

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