/*********************************************************************************
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* Copyright: (C) 2025 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: sigact.c
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* Description: This file sigaction() example program.
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*
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* Version: 1.0.0(10/28/2025)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "10/28/2025 03:39:49 PM"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <execinfo.h>
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int g_sigstop = 0;
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void signal_stop(int signum)
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{
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if( SIGTERM == signum )
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{
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printf("SIGTERM signal detected\n");
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}
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else if( SIGALRM == signum )
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{
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printf("SIGALRM signal detected\n");
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g_sigstop = 1;
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}
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}
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void signal_user(int signum)
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{
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if(SIGUSR1 == signum)
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{
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printf("SIGUSR1 signal detected\n");
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}
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else if(SIGUSR2 == signum)
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{
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printf("SIGUSR2 signal detected\n");
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}
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g_sigstop = 1;
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}
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void signal_code(int signum)
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{
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if(SIGBUS == signum)
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{
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printf("SIGBUS signal detected\n");
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}
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else if(SIGILL == signum)
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{
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printf("SIGILL signal detected\n");
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}
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else if(SIGSEGV == signum)
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{
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printf("SIGSEGV signal detected\n");
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}
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exit(-1);
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}
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int main(int argc, char **argv)
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{
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char *ptr=NULL;
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struct sigaction sigact, sigign;
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/*+--------------------------------------+
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*| Method1: Use signal() install signal |
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*+--------------------------------------+*/
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signal(SIGTERM, signal_stop);
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signal(SIGALRM, signal_stop);
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signal(SIGBUS, signal_code);
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signal(SIGILL, signal_code);
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signal(SIGSEGV, signal_code);
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/*+-----------------------------------------+
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*| Method2: Use sigaction() install signal |
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*+-----------------------------------------+*/
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/* Initialize the catch signal structure. */
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sigemptyset(&sigact.sa_mask);
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sigact.sa_flags = 0;
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sigact.sa_handler = signal_user;
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/* Setup the ignore signal. */
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sigemptyset(&sigign.sa_mask);
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sigign.sa_flags = 0;
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sigign.sa_handler = SIG_IGN;
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sigaction(SIGINT, &sigign, 0); /* ignore SIGINT signal by CTRL+C */
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sigaction(SIGUSR1, &sigact, 0); /* catch SIGUSR1 */
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sigaction(SIGUSR2, &sigact, 0); /* catch SIGUSR2 */
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printf("Program start running for 5 seconds...\n");
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alarm(5);
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while( !g_sigstop )
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{
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;
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}
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printf("Program start stop running...\n");
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printf("Invalid pointer operator will raise SIGSEGV signal\n");
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*ptr = 'h';
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return 0;
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}
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