逆向 | linux c父子进程通信模板

#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
 
int main(){
        pid_t pid;      //parent_id
        pid_t cid;      //child_pid
        printf("Before fork Process id: %d\n", getpid());
        
	int fields[2]; // create pipe
	char buffer[1024] = {0};
	if(pipe(fields)!=0){
		printf("Createpipe error \n");
		exit(1);
	}

	cid = fork();
        if(cid==0){     // child
                printf("Child process id(my parent id is %d): %d\n", getppid(), getpid());
		close(fields[0]);
		//char s[] = "from child! \n";
                //write(fields[1], s, sizeof(s));
		//printf("send ok \n");
		// 将子进程的输出由标准输出重定向到 fields 的管道写端上
  		dup2(fields[1], 1);
		// 替换执行脚本
		execl("/bin/ls", "ls", "-la", NULL);

		exit(0);
        }else {         // father
                printf("Parent process id: %d\n", getpid());
		wait(NULL);
		printf("ready to recv \n");
		int x = read(fields[0], buffer, sizeof(buffer));
		printf("recv %d: %s \n",x,  buffer);
		//close(fields[0]);
        }
        printf("After fork, Process id: %d\n", getpid());
        return 0;
}