操作系统上机实验五

实验五命名匿名管道通信

【实验软硬件环境】

Linux、Win11、GCC

【实验目的与内容】

学习使用命名匿名管道在多进程间建立通信。

建立父子进程，由父进程创建一个命名匿名管道，由子进程向命名管道写入数据，由父进程从命名管道读取数据。

【实验程序及分析】

Windows下

父进程代码father.cpp

#include <windows.h>
#include <process.h>
#include <cstring>
#include <stdio.h>

int main() {
	HANDLE hPipeRead;
	HANDLE hPipeWrite = CreateNamedPipe(TEXT("\\\\.\\Pipe\\test_write"), PIPE_ACCESS_DUPLEX,//创建命名管道 
							PIPE_READMODE_BYTE | PIPE_WAIT, PIPE_UNLIMITED_INSTANCES, 0, 0, NMPWAIT_WAIT_FOREVER, NULL);
	
	STARTUPINFO si = {0};//si进程创建
	ZeroMemory(&si, sizeof(STARTUPINFO));
	PROCESS_INFORMATION pi = {0};
	BOOL bSuccess = CreateProcess(TEXT("child.exe"), NULL, NULL, NULL, TRUE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi);//创建子进程
	
	if (ConnectNamedPipe(hPipeWrite, NULL)) {
		printf("Connected\n");
		printf("Send signal? [Y/n]\n");
		char ch;
		scanf("%c",&ch);
		if (ch == 'y' || ch == 'Y') {
			DWORD dwWrite;
			const char* ptr = "start";
			if (!WriteFile(hPipeWrite, ptr, strlen(ptr), &dwWrite, NULL)) {
				printf("ERROR\n");
			}
			printf("Signal sent success\n");
		}
		
		Sleep(1000);
		hPipeRead = CreateFile(TEXT("\\\\.\\Pipe\\test_read"), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
		//创建文件存储读取来自管道的数据
		char buffer[4096] = {0};
		DWORD dwRead = 0;
		BOOL rSuccess = false;
		
		while (TRUE) {
			rSuccess = ReadFile(hPipeRead, buffer, 4096, &dwRead, NULL);
			if (!rSuccess) {
				break;
			}
			
			printf("Received: %s", buffer);
		}
	}
	
	DisconnectNamedPipe(hPipeWrite);
	CloseHandle(hPipeWrite);
	DisconnectNamedPipe(hPipeRead);
	CloseHandle(hPipeRead);
	system("pause");
	return 0;
}

子进程代码child.cpp

#include <windows.h>
#include <process.h>
#include <cstring>
#include <cstdio>

int main() {
	if (WaitNamedPipe(TEXT("\\\\.\\Pipe\\test_write"), NMPWAIT_WAIT_FOREVER)) {//等待函数
		HANDLE hPipeWrite;
		printf("Connection successful\n");
		
		HANDLE hPipeRead = CreateFile(TEXT("\\\\.\\Pipe\\test_write"), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
		//创建读文件句柄管道
		char buffer[4096] = {0};
		DWORD dwRead = 0;
		BOOL rSuccess = false;
		
		while (TRUE) {
			rSuccess = ReadFile(hPipeRead, buffer, 4096, &dwRead, NULL);
			if (!rSuccess) {
				break;
			}
			printf("%s\n", buffer);
			if (buffer[0] == 's') {
				printf("Received signal.\n");
				
				hPipeWrite = CreateNamedPipe(TEXT("\\\\.\\Pipe\\test_read"), PIPE_ACCESS_DUPLEX, //创建写文件内容管道
							PIPE_READMODE_BYTE | PIPE_WAIT, PIPE_UNLIMITED_INSTANCES, 0, 0, NMPWAIT_WAIT_FOREVER, NULL);
				if (ConnectNamedPipe(hPipeWrite, NULL)) {
					FILE *fp = fopen("example.txt", "r");
					char s[4096] = {0};
					while (fgets(s, 100, fp) != NULL) {
						DWORD dwBytesWritten;
						WriteFile(hPipeWrite, s, 4096, &dwBytesWritten, NULL);
						printf("Sent: %s", s);
					}
					fclose(fp);
					break;
				}
				
				
			}
		}
		
		FlushFileBuffers(hPipeRead);
		DisconnectNamedPipe(hPipeRead);
		CloseHandle(hPipeRead);
		DisconnectNamedPipe(hPipeWrite);
		CloseHandle(hPipeWrite);
	}
	Sleep(10000);
	return 0;
}