这个程序的作用就是 前台输入的 数据通过管道传递给后台的 sh 进程 然后将执行的结果返回到前台
linux 的管道使用要注意 一个管道 只能一端读 一端 写 当创建完子进程后 父进程和子进程都需要关闭管道的一端 因为 没必要自己写 自己读 此处 需要使用两个管道
#include#include #include #include #include #include #include #include #include #include int read_pipe[2];int write_pipe[2];void MyCreateThread(void *(*func)(void *),void *lparam){ pthread_attr_t attr; pthread_t p; pthread_attr_init(&attr); pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_DETACHED); pthread_create(&p,&attr,func,lparam); pthread_attr_destroy(&attr);}void *read_thread(void *lparam){ char cmd[100]; int bytes = 0; while((bytes = read(STDIN_FILENO,cmd,100)) > 0) { write(write_pipe[1],cmd,bytes); } return NULL;}int main(int argc, char *argv[]){ int pid; pipe(read_pipe); pipe(write_pipe); pid = fork(); if(0 == pid) { //进入子进程 // 启动 shell 进程 close(read_pipe[0]); close(write_pipe[1]); char *argv[] = {"/bin/sh",NULL}; char *shell = "/bin/sh"; dup2(write_pipe[0],STDIN_FILENO); //将输入输出重定向到管道 dup2(read_pipe[1],STDOUT_FILENO); dup2(read_pipe[1],STDERR_FILENO); execv(shell,argv); } else { char buff; close(read_pipe[1]); close(write_pipe[0]); printf("child process id %d \n",pid); write(write_pipe[1],"ls\n",3); //启动一个线程来读取 MyCreateThread(read_thread,NULL); while(read(read_pipe[0],&buff,1) > 0) { putchar(buff); } waitpid(pid,NULL,0); printf("child exit. ..\n"); } return 0;}