C: Pass socket connection via execl - c

Question

I am attempting to create a basic server that supports multiple clients. I want the main server to connect to two clients, and then fork off and pass the file descriptors for the clients to another program via a call to execl. Both of the clients connect to the server and are able to communicate with it (tested via asking the clients for user names or handles), but when I attempt to pass the clients to the second program (which is meant to be a personal server between the clients to host a board game match) no output is shown on the client's end when the second program attempts to contact them, I am positive it is the way I am attempting to pass the connection information. Any help with passing the connections correctly is appreciated.
Here is the code for the main server after it accepts two connections:
Main Server: Note. Added additional error checking as recommended.
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);
}
The personal server(different .c file than main server): Note. Added debuging statements
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;
}
And the client code after it has been connected and matched with an opponent:
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);
If more code is needed let me know, I know that the clients successfully connect to the server and I get no errors when compiling or running.
The suggested answer from EJP ensures the private server receives the correct input, but the client does not appear to be storing the string from the private server. The adjusted client code below states that the client is receiving 64 bytes but the buf is empty.
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);

Answer 1

You're passing the arguments to execl() incorrectly. It doesn't take an argument array, it takes a varargs list of arguments. It should be
execl(path, connAscii, connAscii2, (char*)0);