我正在尝试创建一个支持多个客户端的基本服务器。我希望主服务器连接到两个客户端,然后分叉并通过调用execl将客户端的文件描述符传递给另一个程序。两个客户端都连接到服务器并且能够与它通信(通过向客户端询问用户名或句柄进行测试),但是当我尝试将客户端传递给第二个程序时(这意味着它们之间是个人服务器)主持棋盘游戏的客户端)当第二个程序试图联系他们时,客户端没有显示输出,我很肯定这是我尝试传递连接信息的方式。任何有关正确传递连接的帮助都表示赞赏。
以下是主服务器接受两个连接后的代码:
主服务器:注意。根据建议添加了额外的错误检查。
if(fork() == 0){
close(listener);
int nBytes;
char* playerOne[20];
char* playerTwo[20];
//Creates strings to hold file descriptor information for execl
char connAscii[sizeof(int)];
char connAscii2[sizeof(int)];
snprintf(connAscii,sizeof(conn), "%d", conn);
snprintf(connAscii2,sizeof(conn2), "%d", conn2);
fprintf(stderr, "Int conn: %d, asciiConn: %s, backToInt: %d", conn, connAscii, atoi(connAscii));
char *argf[2];
argf[0] = connAscii;
argf[1] = connAscii2;
//Send Handle Request to Connection 1
nBytes = send(conn, handleRequest, sizeof(handleRequest),0);
if(nBytes == -1){
perror("send");
exit(1);
}
//Receive Handle from Connection 1
nBytes = recv(conn, playerOne, 20, 0);
if(nBytes == -1){
perror("recv");
exit(1);
}
//Send Handle Request to Connection 2
nBytes = send(conn2, handleRequest, sizeof(handleRequest),0);
if(nBytes == -1){
perror("send");
exit(1);
}
//Receive Handle from Connection 2
nBytes = recv(conn2, playerTwo, 20, 0);
if(nBytes == -1){
perror("recv");
exit(1);
}
//Send Handle for Connection 2 to Connection 1
nBytes = send(conn, playerTwo, sizeof(playerTwo),0);
if(nBytes == -1){
perror("send");
exit(1);
}
//Send Handle for Connection 1 to Connection 2
nBytes = send(conn2, playerOne, sizeof(playerOne),0);
if(nBytes == -1){
perror("send");
exit(1);
}
//Passes file descriptors to nimMatch
execl("nimMatch", "nimMatch", argf, (char *)0);
}
个人服务器(与主服务器不同的.c文件):注意。添加了debuging语句
char greet[] = {"Hello players, please wait for match setup."};
int main(int argc, char *argv[]) {
int conn1 = atoi(argv[1]);
int conn2 = atoi(argv[2]);
int sent;
fprintf(stderr, "Attempting connection\n");
sent = send(conn1, greet,sizeof(greet),0);
if(sent == -1){
perror("send");
exit(1);
}
return 0;
}
之后的客户端代码已连接并与对手匹配:
printf("Your opponent is: %s\n\n Connecting to match server...", otherHandle);
memset(&buf[0],0,sizeof(buf));
if ((numbytes = recv(sockfd, buf, 99, 0)) == -1) { //should come from personal server
perror("recv");
exit(1);
}
printf("From match server: %s\n", buf);
如果需要更多代码,请告诉我,我知道客户端成功连接到服务器,编译或运行时没有错误。
EJP建议的答案可确保私有服务器收到正确的输入,但客户端似乎没有存储来自私有服务器的字符串。下面调整的客户端代码表明客户端正在接收64字节,但buf为空。
printf("You're opponent is: %s\n\n Connecting to match server...", otherHandle);
memset(&buf[0],0,sizeof(buf));
numbytes = recv(sockfd, buf, 99, 0);
if (numbytes == -1) {
perror("recv");
exit(1);
}
if(strlen(buf) < 1)
fprintf(stderr, "No buffer input, found %d bytes\n", numbytes);
printf("From match server: %s\n", buf);
答案 0 :(得分:2)
您错误地将参数传递给execl()
。它不需要参数数组,它需要一个varargs参数列表。它应该是
execl(path, connAscii, connAscii2, (char*)0);