asked on

EPIPE in send(), Berkley sockets

I have a client application that runs on Linux RH, and a server the runs on WinXP.From the client application I connect to the server, then i try to send some data, and I receive an EPIPE error. In documentation it says that this error ocurs when the peer socket is closed, but in the server I don't close the client socket.
Funny is that, i have a version of the client on WinXP, which works fine.
Any ideea?

Thanks,
marius

skian

Have you checked whether the connect() call succeeded ?
Do you use a async connect() ?

You said that when both the client & server are on
winxp the client works fine. Are the client and the
server running on different hosts ?

Stephane

J0ker

[EPIPE] The socket is shut down for writing, or the socket is
connection-oriented and the peer is closed or shut down for read-
ing. In the latter case, and if the socket is of type
SOCK_STREAM, the SIGPIPE signal is generated to the calling pro-
cess.

SIGPIPE signal maybe? Signal interrupt any blocking operations in blocking socket.

cmaryus

ASKER

I just don't get it...i've made 2 very small test projects: client and server. I've tested in this way:
- start client
- client trying to conect...in keeps receiving ECONREFUSED
- start server
- in this moment client is connected
- on the server side i try to receive data from client
- when i try to send data from client I receive EPIPE (of course this comes with SIGPIPE, which I ignore)

If I do in this way:
- start server first
- start client
- client is connected ok
- client send ok !!!

So when i start the server first ...everything is ok !!!!
When i start the client first...EPIPE...

On Win XP the it works, no matter if i start the client or server first...

skian

could you post the relevant source code part ?

cmaryus

ASKER

This is a small test i've made...

Client:
client.cpp

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <iostream.h>
#include <errno.h>

int main(int argc, char* argv[])
{
signal(SIGPIPE, SIG_IGN);

int sock = socket(AF_INET, SOCK_STREAM, 0);

while(true)
{

sockaddr_in sockAddr;
memset(&sockAddr,0,sizeof(sockAddr));

sockAddr.sin_family = AF_INET;
sockAddr.sin_addr.s_addr = inet_addr(argv[1]);
sockAddr.sin_port = htons((u_short)(atoi(argv[2])));

int x = connect(sock, (struct sockaddr*)&sockAddr, sizeof(sockAddr));
if (x == 0)
{
break;
}
else
{
cout << "Connect err: " << strerror(errno) << endl;
}
usleep(1000000);
}

cout << "connect ok" << endl;

char szMsg[100];
strcpy(szMsg, "test");
while(true)
{
int x = send(sock, szMsg, strlen(szMsg), 0);
if (x == -1)
{
cout << "send err " << strerror(errno) << endl;
}
else
{
cout << "send OK" << endl;
}
usleep(1000000);
}

shutdown(sock, 2);
}

Server:
server.cpp

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/time.h>
#include <fcntl.h>

int main(int argc, char* argv[])
{
signal(SIGPIPE, SIG_IGN);

int sock = socket(AF_INET, SOCK_STREAM, 0);

sockaddr_in sockAddr;
memset(&sockAddr,0,sizeof(sockAddr));

sockAddr.sin_family = AF_INET;
sockAddr.sin_addr.s_addr = inet_addr(argv[1]);
sockAddr.sin_port = htons((u_short)(atoi(argv[2])));

int x = bind(sock, (struct sockaddr*)&sockAddr, sizeof(sockAddr));
if (x == 0)
{
printf("\nbind ok");;
}
else
{
perror("\n bind ");
}

listen(sock, 5);

int xxx;

while(true)
{

xxx = accept(sock, NULL, NULL);
if (xxx == -1)
{
perror("\n accept ");
}
else
{
printf("\n accept ok");
break;
}
usleep(100000);
}

fcntl(xxx, F_SETFL, O_NONBLOCK);

char msg[100];
int zzzz = recv(xxx, msg, 10, 0);

shutdown(sock, 2);
}

You start the processes like this:
client 10.11.12.13 1111
server 10.11.12.13 1111
(first param ip, second port)
If i start the client first-> send fails
If i start the server first, then client , the send is ok !

Please help...I'm desperate...i'm working on this since thursday...

cmaryus

ASKER

Until now I made the test on a RH6.2. When I make the tests on RH8.0...it works....could this be the problem?

ASKER CERTIFIED SOLUTION

skian

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cmaryus

ASKER

I know what fcntl does, i tested without it and still the same.

skian

so print zzzz value

cmaryus

ASKER

when in the blocking mode, recv don't return at all. in send i receive EPIPE...

cmaryus

ASKER

Thanks guys but I've succeeded to solve this problem: in the client code, after each unsuccessfull connect i close and create the socket again.
So I hope it's ok to get my points back...

Kyle Abrahams, PMP

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