linux系统编程之信号 test10

本文介绍了一个使用C语言实现的程序，该程序通过注册信号处理函数来响应SIGINT、SIGTERM和SIGCONT信号，并利用实时定时器进行周期性的操作。程序还展示了如何阻止信号并检查待处理信号的数量。

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <stdarg.h>
#include <time.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>

int my_printf(const char *fmt,...);
void sighandler(int signum);
void continuehandler(int signumber);
char buffer[200];

int main(void)
{
struct itimerval itimer;
sigset_t blockset,pending;
int pendingcount;
strcpy(buffer,"None\n");
if(signal(SIGINT,&sighandler)==SIG_ERR)
{
my_printf("Couldn't register signal handler for SIGINT.\n");
}
if(signal(SIGTERM,&sighandler)==SIG_ERR)
{
my_printf("Couldn't register signal handler for SIGTERM.\n");
}
if(signal(SIGCONT,&sighandler)==SIG_ERR)
{
my_printf("Couldn't register signal handler for SIGCONT.\n");
}
sigemptyset(&blockset);
sigaddset(&blockset,SIGINT);
sigaddset(&blockset,SIGTERM);
itimer.it_interval.tv_usec=0;
itimer.it_interval.tv_sec=15;
itimer.it_value.tv_usec=0;
itimer.it_value.tv_sec=15;
for(;;)
{
sigprocmask(SIG_BLOCK,&blockset,NULL);
// alarm(15);
setitimer(ITIMER_REAL,&itimer,NULL);
fgets(buffer,sizeof(buffer),stdin);
my_printf("input:%s",buffer);
sigpending(&pending);
pendingcount=0;
if(sigismember(&pending,SIGINT))
pendingcount++;
if(sigismember(&pending,SIGTERM))
pendingcount++;
if(pendingcount)
{
my_printf("There are %d signals.\n",pendingcount);
}
sigprocmask(SIG_UNBLOCK,&blockset,NULL);
if(strcmp(buffer,"exit\n")==0)
{
raise(SIGKILL);
}
}
return 0;
}

int my_printf(const char *fmt,...)
{
va_list args;
struct tm *tstruct;
time_t tsec;
tsec=time(NULL);
tstruct=localtime(&tsec);
printf("%02d:%02d:%02d %05d\n",tstruct->tm_hour,tstruct->tm_min,tstruct->tm_sec,getpid());
va_start(args,fmt);
return vprintf(fmt,args);
}

void sighandler(int signumber)
{
my_printf("Caught sight %d.\n",signumber);
}

void continuehandler(int signumber)
{
my_printf("Continuint.\n");
my_printf("Your last input was: %s",buffer);
}

/*
void alarmhandler(int signumber)
{
my_printf("No activity for 15 seconds,exiting.\n");
exit(0);
}
*/