linux进程间通信、异步信号处理机制

linux实验报告9、10章

 

第九章 进程间通信(管道)

实验9-4

实现一个服务器和多个客户端之间的通信:

(1)服务器创建一个有名管道,供客户端写入信息.

(2)每个客户端为自己创建有名管道.供服务器写入信息.

(3)客户端打印出发送到服务器的信息,从服务器接受到的信息

 

题目分析:

使用MUFIFO作为命题管道,使用fopen函数打开对应的命名管道,然后将argv中的字符串写入该命名管道中.创建fifosend.c

与之前相类似,使用fopen函数打开命名为MYFIFO的管道文件,然后从其中读出对应的字符串并显示在屏幕上.创建fifoget.c

 

实验结果:

 

实验代码:

//fifosend.c   #include<stdio.h> #include<stdlib.h> #include<sys/types.h>   #define FIFO_FILE "MYFIFO"   int main(int argc, char *argv[]) {         FILE *fp;         int i;         if(argc<2)         {                 printf("please use :%s<pathname>\n", argv[0]);                 exit(1);         }         if((fp=fopen(FIFO_FILE,"w")) == NULL)         {                 printf("fopen error!\n");                 exit(1);         }         for(i=1;i<argc;i++)         {                 if(fputs(argv[i],fp) == EOF)                 {                         printf("write fifo error!\n");                         exit(1);                 }                 if(fputs("",fp) == EOF)                 {                         printf("write fifo error!\n");                         exit(1);                 }         }         fclose(fp);         return 0; }

 

//fifoget.c   #include<stdio.h> #include<stdlib.h> #include<sys/stat.h> #include<unistd.h> #include<linux/stat.h> #include<errno.h>   #define FIFO_FILE "MYFIFO"   int main(int argc, char argv[]) {         FILE *fp;         char readbuf[80];           if((fp=fopen(FIFO_FILE, "r")) == NULL)         {                 umask(0);                 mknod(FIFO_FILE,S_IFIFO|0666,0);         }         else         {                 fclose(fp);         }         while(1)         {                 if((fp=fopen(FIFO_FILE, "r")) == NULL)                 {                         printf("open fifo error!\n");                         exit(1);                 }                 if(fgets(readbuf, 80, fp)!=NULL)                 {                         printf("get the readbuf is : %s\n", readbuf);                         fclose(fp);                 }                 else                 {                         if(ferror(fp))                         {                                 perror("read file error!\n");                                 exit(1);                         }                 }         }         return 0; }

 

 

 

 

 

第十章 异步信号处理机制

实验10-1

编写程序测试函数setitimer(int)和getitimer()。

安装信号, 使信号SIGALRM、SIGVTALRM、SIGPROF可以被捕获。

测试:setitimer()函数

运行结果:

 

实验代码:

//setitimer.c   #include<stdlib.h>   static void signalDeal(int signo) {         struct timeval tp;         struct tm *tm;         gettimeofday(&tp,NULL);         tm=localtime(&tp.tv_sec);         system("clear");         printf("sec=%d\t",tp.tv_sec);         printf("usec=%d\n",tp.tv_usec);         printf("%d-%d-%d  %d:%d:%d\n",tm->tm_year+1900,tm->tm_mon+1,tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec); }   static void InitTime(int tv_sec,int tv_usec) {         struct itimerval value;         signal(SIGALRM,signalDeal);         value.it_value.tv_sec=tv_sec;         value.it_value.tv_usec=tv_usec;         value.it_interval.tv_sec=tv_sec;         value.it_interval.tv_usec=tv_usec;         setitimer(ITIMER_REAL,&value,NULL); }   int main(int argc,char *argv[]) {         InitTime(1,0);         while(1)         {         }         exit(0); }

实验10-2

编写程序测试sigaction()函数。

sa_flags 设置为以下标志时，程序的行为有何不同。

对比程序运行情况予以说明。

SA_SIGINFO

SA_NOCLDSTOP

SA_NOCLDWAIT

SA_NODEFER

SA_RESETHAND

 

测试sigaction()函数

运行结果:

 

 

测试sigaction2()函数

运行结果:

 

函数代码:

//sigaction.c   #include<stdio.h> #include<stdlib.h> #include<signal.h>   void signalDeal(int sig,siginfo_t*info,void *t) {         if(sig==SIGINT) //CTRL+C         {                 printf("使用CTRL+C!\n");         }         else if(sig==SIGQUIT) //CTRL+/         {                 printf("使用CTRL+/!\n");         }         else         {                 printf("其他信号!\n");         } }   int main(int argc,char *argv[]) {         struct sigaction act;         act.sa_sigaction = signalDeal;         sigemptyset(&act.sa_mask);         act.sa_flags=SA_SIGINFO;         sigaction(SIGINT,&act,NULL);         sigaction(SIGQUIT,&act,NULL);         while(1)         {         }         return 0; }

 

//sigaction2.c   #include <stdio.h> #include <unistd.h> #include <signal.h> #include <errno.h>   static void sig_usr(int signum) {     if(signum == SIGUSR1)     {         printf("SIGUSR1 received\n");     }     else if(signum == SIGUSR2)     {         printf("SIGUSR2 received\n");     }     else     {         printf("signal %d received\n", signum);     } }   int main(void) {     char buf[512];     int  n;     struct sigaction sa_usr;     sa_usr.sa_flags = 0;     sa_usr.sa_handler = sig_usr;   //信号处理函数     sigaction(SIGUSR1, &sa_usr, NULL);     sigaction(SIGUSR2, &sa_usr, NULL);     printf("My PID is %d\n", getpid());     while(1)     {         if((n = read(STDIN_FILENO, buf, 511)) == -1)         {             if(errno == EINTR)             {                 printf("read is interrupted by signal\n");             }         }         else         {             buf[n] = '\0';             printf("%d bytes read: %s\n", n, buf);         }     }     return 0; }

 

 

 

测试sigprocmask()函数

运行结果:

 

 

 

实验代码:

//sigprocmask.c   #include <stdio.h> #include <unistd.h> #include <signal.h> #include <stdlib.h>   static void sig_quit(int signo) {         printf("caught SIGQUIT\n");         signal(SIGQUIT, SIG_DFL);//再次安装 } int main() {         sigset_t newmask, oldmask, pendmask;           signal(SIGQUIT, sig_quit);//安装信号处理函数           sigemptyset(&newmask);//初始化信号量集         sigaddset(&newmask, SIGQUIT);//将SIGQUIT添加到信号量集中           sigprocmask(SIG_BLOCK, &newmask, &oldmask);//将newmask中的SIGQUIT阻塞掉，并保存当前信号屏蔽字,原来值读到oldmask.           sleep (5);//休眠5秒钟           sigpending(&pendmask);//检查信号是否SIGQUIT被阻塞还没有被处理           if (sigismember(&pendmask, SIGQUIT))//SIGQUIT被阻塞还没有被处理         {                 printf("\nSIGQUIT pending\n");         }           sigprocmask(SIG_SETMASK, &oldmask, NULL);//恢复被屏蔽的信号SIGQUIT           printf("SIGQUIT unblocked\n");           sleep(5);//再次休眠5秒钟           return (0); }

 

 

测试信号集

实验结果:

 

实验代码:

#include<signal.h> #include<stdio.h> #include<stdlib.h>   int output(sigset_t set);   int main() {         sigset_t set;         printf("after empty the set:\n");         sigemptyset(&set);         output(set);           printf("after add signo=7:\n");         sigaddset(&set,7);         output(set);         printf("after add signo=13:\n");         sigaddset(&set,13);         output(set);           return 0; }   int output(sigset_t set) {         int i=0;         for(i=0;i<1;i++)         {                 printf("0x%8x\n", set.__val[i]);                 if((i+1)%8==0)                         printf("\n");         } }