我一直在使用该网站一段时间（本学期结束后）期待回馈！但是，我最后一次想要你的帮助，似乎没有任何其他答案提供任何帮助。
背景：使用c ++，套接字和客户端/服务器架构设计基本聊天室，最多有10个客户端与服务器通信。客户端所说的任何内容都会在所有客户端和服务器之间回显（发送客户端除外）。
问题：在recv调用中发生错误，因为clientTalk函数中的while循环条件。我得到一个“接收失败：错误的文件描述符”，但服务器和客户端都没有完全“崩溃”，并且没有发生明显的行为变化，尽管接收完全遭到轰炸。
要解决的问题：
Google和SOF。 2小时......
移动变量，玩套接字设置和打开/关闭
-Valgrind：
==773== Warning: invalid file descriptor 96600128 in syscall read()
Recieve failed: Bad file descriptor
==773== Thread 2:
==773== Conditional jump or move depends on uninitialised value(s)
==773== at 0x4015A0: ??? (in /nethome/users/ghm455/CS284/ChatServer/server)
==773== by 0x4E39E99: start_thread (pthread_create.c:308)
==773== by 0x5442CBC: clone (clone.S:112)
==773==
==773== Conditional jump or move depends on uninitialised value(s)
==773== at 0x401614: ??? (in /nethome/users/ghm455/CS284/ChatServer/server)
==773== by 0x4E39E99: start_thread (pthread_create.c:308)
==773== by 0x5442CBC: clone (clone.S:112)
==773==
==773== Warning: invalid file descriptor 96600128 in syscall close()
第一个警告发生在我的接受声明中。接收失败发生在recv上，最后一次警告发生在尝试关闭时。这是由整个代码中散布的cout语句决定的。
代码：下面。如果您认为错误在那里，我会发布客户端，但是所有内容都指向这是服务器端问题。`#define SERVER_PORT 9999 /* define a server port number */
using std::cout;
using std::endl;
using std::string;
//Globals - descriptorArray holds client FDs. arraySize is its size.
//soc holds the information on the server's socket.
//m is the global mutex shared among the server and all clients
const int MAX_CLIENT = 10;
int descriptorArray[MAX_CLIENT];
int arraySize = 0;
int soc;
pthread_mutex_t m;
struct thread_info
{
pthread_t threadID; //Stores the ID number returned by pthread_create
int threadNumber; //We have to number incoming threads correctly
char *messageSent; //Message taken in from command line
};
int main()
{
void exitHandler(int sig); // Function that handles the control-C
void* clientTalk(void *arg); // Reads and writes with clients
struct sockaddr_in server_addr, client_addr;
int option = 1;
unsigned int clientCount;
uint8_t *new_socket;
//Initialize the socket
soc = socket(AF_INET, SOCK_STREAM, 0);
if (soc < 0)
{
cout << "ERROR : problem opening socket" <<endl;
return 1;
}
//Create socket structure
bzero((char *) &server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = htons(SERVER_PORT);
//Binding host address
if (bind(soc, (struct sockaddr *) &server_addr, sizeof(server_addr)) < 0)
{
cout << "ERROR : problem occured while binding" <<endl;
close(soc);
exit(1);
}
if(setsockopt(soc, SOL_SOCKET, SO_REUSEADDR, (char*) &option, sizeof(option)) < 0)
{
printf("setsockopt failed\n");
close(soc);
exit(1);
}
signal(SIGINT, exitHandler);
listen(soc, MAX_CLIENT);
clientCount = sizeof(struct sockaddr_in);
int clientID;
//cout << "Z " <<endl;
while(clientID = accept(soc, (struct sockaddr *) &client_addr, (socklen_t*)&clientCount))
{
//printf( "A");
if (clientID < 0 )
{
perror("ERROR ON ACCEPT");
exit(1);
}
else
{
pthread_t newClient;
new_socket = (uint8_t*)malloc(1);
*new_socket = clientID;
pthread_mutex_lock(&m);
if (arraySize < 10)
{
descriptorArray[arraySize++] = newClient;
}
else
{
cout << "There are already 10 clients connected!" << endl;
}
pthread_mutex_unlock(&m);
if( pthread_create(&newClient, NULL, clientTalk, &new_socket) < 0)
{
perror("ERROR Creating thread");
return 1;
}
cout << "Assigned!" <<endl;
pthread_join(newClient, NULL);
}
}
close(soc);
return 0;
}
void exitHandler(int sig)
{
sig = sig + 0; //Removing the warning. A clean compile looks a lot nicer.
for (int i = 0; i < arraySize; i++)
{
write(descriptorArray[i], "WARNING: Server exiting in ten seconds. End your conversation!", 1000);
}
cout << "WARNING: Server exiting in ten seconds. ";
cout << "End your conversation!" << endl;
sleep(10f);
for (int i = 0; i < arraySize; i++)
{
close(descriptorArray[i]);
}
close(soc);
exit(1);
}
void* clientTalk(void* arg)
{
int* myFD = (int*) arg;
char buffer[2000];
read(*myFD, buffer, 20);
char username[20];
//strcpy(username, buffer); // Takes in the username and stores it
char movableString[2000];
int amount_read;
// for (int i = 0; i < arraySize; i++)
// {
//strcpy(movableString, username);
// strcat(movableString, " has joined the room!");
//if (descriptorArray[0] != *myFD)
//{
// write(descriptorArray[0], movableString, 2000);
//}
//}
cout << "x" << endl;
int arrayLocation;
while ( (amount_read = recv(*myFD, buffer, 2000, MSG_WAITALL)) > 0)
{
cout << " Um" << endl;
pthread_mutex_lock(&m);
for (int i = 0; i < arraySize; i++)
{
if (descriptorArray[i] == *myFD)
{
arrayLocation = i;
break;
}
}
strcpy(movableString, username);
strcat(movableString, ": ");
strcat(movableString, buffer);
for (int i = 0; i < arraySize; i++)
{
//if (i != arrayLocation)
//{
write(*myFD, movableString, 2000);
//}
}
pthread_mutex_unlock(&m);
}
if (amount_read == 0)
{
cout << username << "disconnected unexpectedly" <<endl;
fflush(stdout);
}
if (amount_read == -1)
{
perror("Recieve failed");
}
pthread_mutex_lock(&m);
for (int i = 0; i < arraySize; i++)
{
if (descriptorArray[i] == *myFD)
{
arrayLocation = i;
break;
}
}
for (int i = arrayLocation; i < arraySize - 1; i++)
{
descriptorArray[i] = descriptorArray[i + 1];
}
arraySize--;
pthread_mutex_unlock(&m);
close(*myFD);
pthread_exit(NULL);
free(arg);
}
`
我会监控本网站以回答您的任何问题。我提前道歉，因为在提出问题时犯了任何新手错误。
感谢您的帮助！
答案 0 :(得分：1)
错误意味着传递给read函数的文件描述符不是有效的文件描述符，因此调试时要做的第一件事是确保ClientTalk函数中的文件描述符的值与main中的相同。
@ J.N。在评论中是正确的。它们不会是相同的，因为FD是一个int，你只是将第一个字节传递给函数（并将它转换为int *指针。）
您可能希望在C中编写此程序，因为它看起来不像C ++代码。
可能还有其他问题。
答案 1 :(得分：1)
这里至少有两个问题。首先，你永远不会调用pthread_mutex_init所以你的互斥锁从未被创建为一个理智的状态（尽管如果它在全局范围内它将被归零）。
其次，您将&new_socket作为void*传递给您的主题。这是uint8_t**类型，而在你的clientTalk函数中，你将C风格转换为int*，这是一个完全不同的指针类型，肯定不会提供你想要的结果。 / p>