fread hanging, C++ with pipes - c++

Question

I'm writing a tictactoe application which communicates between a server and client file. Currently, my program hangs when trying to read in the players move. The client is showing successful write to the pipe but the server is not reading the information. Any help would be appreciated. Heres the offending code from both portions. Edit: I just realized the formatting got completely buggered in the copy/paste, I am sorry.
client main() :
//used to define int holder for server read in
const int MAX = 2;
//used to define buffers to transfer information
const int BUFFERS = 10;
//path of the global pipe
const string PRIMARY = "/home/mking/GPipe";
int main() {
//variables
size_t result;
srand(time(NULL) );
int s = rand() % 10000;
if (s < 1000) { s += 1000; }
cout << s << endl;
string userWrite = "/temp/" + to_string(s);
s = rand() % 10000;
if (s < 1000) { s += 1000; }
cout << s << endl;
string serverWrite = "/temp/" + to_string(s);
cout << PRIMARY << endl;
cout << "User pipe is " << userWrite << endl;
cout << "Server pipe is " << serverWrite << endl;
// send personal pipe information through global pipe to server
FILE * comms = fopen(PRIMARY.c_str(), "w");
cout << "Comms open" << endl;
result = fwrite(userWrite.c_str(), 1, userWrite.length(), comms);
if (result < userWrite.length()) { cout << endl << endl << endl << endl << endl << "write error, userfifo" << endl; }
result = fwrite(serverWrite.c_str(), 1, serverWrite.length(), comms);
if (result < userWrite.length()) { cout << endl << endl << endl << endl << endl << "write error, serverfifo" << endl; }
cout << "Comms written to" << endl;
//done with comms so close it
fclose(comms);
// for some reason sending /tmp/ caused a hang also, so i improvised
userWrite.erase(2,1);
serverWrite.erase(2,1);
// make the personal pipes
cout << userWrite << " " << serverWrite << endl;
mkfifo(userWrite.c_str(), 0777);
mkfifo(serverWrite.c_str(), 0777);
// open the personal pipes with read or write privelege
cout << "fifos made" << endl;
FILE * pwrite = fopen(userWrite.c_str(), "w");
cout << "pwrite open" << endl;
FILE * pread = fopen(serverWrite.c_str(), "r");
cout << "pread open" << endl;
// if either pipe did not get made correctly, print an error
if (pwrite == NULL ) { cout << "pwrite is wrong" << endl; }
if (pread == NULL ) { cout << "pread is wrong" << endl; }
// used to transfer information between pipes
string buffer = "/temp/0000";
string catcher = "/temp/0000";
// initialize curses functions
initscr();
noecho();
keypad(stdscr,TRUE);
cbreak();
WINDOW * screen = newwin(LINES/2, COLS/2, 0, 0);
wclear(screen);
keypad(screen,TRUE);
//wait for input before playing the game
int c = getch();
displayOpening(screen);
c = getch();
//initialize the game data types
int row = 0;
int column = 0;
vector<pair<int, int> > userMoves;
vector<pair<int,int> > serverMoves;
int charInt[MAX];
bool invalid = 0;
//until game is over or user exits
while (1) {
// update the board
displayBoard(screen,userMoves,serverMoves, row, column, invalid);
// based on user input, do stuff, supports wsad or arrow keys
switch(c = getch() ) {
// if go up, move up a row or go back to bottom if at top
case KEY_UP:
case 'w':
if (row == 0) { row = 2; }
else { row--; }
break;
// if go down, move down a row or go back to the top if at bottom
case KEY_DOWN:
case 's':
if (row == 2) { row = 0; }
else { row++; }
break;
// if go left, move left a column or go back to the far right if at far left
case KEY_LEFT:
case 'a':
if (column == 0) { column = 2; }
else { column--; }
break;
// if go right, move right a column or go back to the far left if at far right
case KEY_RIGHT:
case 'd':
if (column == 2) { column = 0; }
else { column++; }
break;
// if spacebar is pressed, enter move if valid, otherwise tell invalid and get more input
case ' ':
if (checkX(row, column, userMoves, serverMoves)) {
invalid = 0;
// no longer used function, thought maybe was the issue
//addX(row,column,userMoves,buffer);
//catch information in buffer to send to server
buffer[8] = (row + '0');
buffer[9] = (column + '0');
//cout << "buffer 0 and 1 are " << int(buffer[0]) << " " << int(buffer[1]) << endl;
// add newest move to the list of user moves
userMoves.push_back(make_pair(row,column));
// check if the game is over, send a game over message to server if so and exit/clean up pipes
if (checkValid(userMoves,serverMoves) == 0 || (userMoves.size() + serverMoves.size() == 9) ) {
youwin(screen);
buffer[8] = (3 + '0');
buffer[9] = (3 + '0');
result = fwrite(buffer.c_str(), 1, buffer.length(), pwrite);
if (result < BUFFERS) { cout << endl << endl << endl << endl << endl << "write error, usermove" << endl; }
fclose(pread);
fclose(pwrite);
unlink(userWrite.c_str());
unlink(serverWrite.c_str());
endwin();
return 0;
}
//mvwaddch(screen, 12, 1, 'k');
//wrefresh(screen);
//cout << endl << endl << endl << endl << endl << buffer << " " << buffer.length() << endl;
// write newest move to server, currently where hangs!!!!!!
result = fwrite(buffer.c_str(),1,buffer.length(),pwrite);
if (result < BUFFERS) { cout << endl << endl << endl << endl << endl << "write error, usermove" << endl; }
//cout << endl << "written successfully" << endl;
//mvwaddch(screen,12,1,'l');
//wrefresh(screen);
// read in server counter move
result = fread(&catcher[0],1,BUFFERS,pread);
if (result < BUFFERS) { cout << endl << endl << endl << endl << endl << "read error, servermove" << endl; }
// catch newest computer move
charInt[0] = (catcher[8] - '0');
charInt[1] = (catcher[9] - '0');
// if the server says it won, clean up pipes and exit
if (charInt[0] == 3 && charInt[1] == 3) {
youlose(screen);
fclose(pread);
fclose(pwrite);
unlink(userWrite.c_str());
unlink(serverWrite.c_str());
endwin();
return 0;
}
// check if the server made a valid move
if (checkX(charInt[0], charInt[1], userMoves, serverMoves)) { invalid = 1; }
//addX(charInt[0],charInt[1],serverMoves,catcher);
// add newest server move to list of server moves
serverMoves.push_back(make_pair(charInt[0],charInt[1]));
// if server has won or a draw, tell the server and clean up pipes/exit
if (checkValid(userMoves,serverMoves) == 0) {
youlose(screen);
buffer[8] = (3 + '0');
buffer[9] = (3 + '0');
result = fwrite(&buffer[0],1,BUFFERS,pwrite);
if (result < BUFFERS) { cout << endl << endl << endl << endl << endl << "write error, usermove" << endl; }
fclose(pread);
fclose(pwrite);
unlink(userWrite.c_str());
unlink(serverWrite.c_str());
endwin();
return 0;
}
}
// if the move was invalid say so
else { invalid = 1; }
break;
// if user wants to exit, tell the server and clean up/exit
case 'q':
buffer[8] = 3 + '0';
buffer[9] = 3 + '0';
result = fwrite(&buffer[0],sizeof(char),BUFFERS,pwrite);
if (result < BUFFERS) { cout << endl << endl << endl << endl << endl << "write error, usermove" << endl; }
fclose(pread);
fclose(pwrite);
unlink(userWrite.c_str());
unlink(serverWrite.c_str());
endwin();
return 0;
break;
default:
break;
}
}
return 0;
}
server main() :
const int GRID = 9;
const int MAX_G = 10;
const int MAX_L = 10;
const string PRIMARY="/home/mking/GPipe";
int main() {
// variables to hold personal pipe input
char userWrite[MAX_L];
char serverWrite[MAX_L];
// open global pipe and prepare for input
cout << PRIMARY << endl;
FILE * comms = fopen(PRIMARY.c_str(), "r");
cout << "comms open" << endl;
pid_t pid;
bool valid = 1;
int charInt[MAX_G];
char prev[] = "/temp/0000";
size_t result;
// run until forced to close
while(1) {
// get the personal pipe names
//cout << "about to read user" << endl;
result = fread(&userWrite[0], sizeof(char),MAX_L,comms);
if (result < MAX_L && result > 0) { cout << "read error, user" << endl; }
//cout << "read user" << endl;
result = fread(&serverWrite[0], sizeof(char), MAX_L,comms);
if (result < MAX_L && result > 0) { cout << "read error, server" << endl; }
//cout << "read server" << endl;
//cout << "User pipe is " << userWrite << endl;
//cout << "Server pipe is " << serverWrite << endl;
// if a new pipe was detected, fork and play against a client
if (strcmp(prev, userWrite) != 0) { pid = fork(); }
strcpy(prev, userWrite);
// if a chiled, play against a client
if (pid == 0) {
//close comms and open personal pipes
cout << "In child" << endl;
fclose(comms);
string user(userWrite);
string server(serverWrite);
// was having issues with fread earlier also, roundabout fix
user.erase(2,1);
server.erase(2,1);
// set up pipes
cout << "opened pipes " << user << " " << server << endl;
FILE * userFifo = fopen(user.c_str(), "r");
cout << "opened user pipe" << endl;
FILE * serverFifo = fopen(server.c_str(), "w");
cout << "opened server pipe" << endl;
// set up data for server to check moves
pair<int,int> move;
vector<pair<int,int> > userMoves;
vector<pair<int,int> > serverMoves;
char buffer[MAX_G] = {'/','t','e','m','p','/','0','0' };
char filler[MAX_G];
vector<bool> untaken (GRID, 1);
// while game not over
while (valid) {
// get a new move, HANGS HERE!!!!!
cout << "waiting for user move" << endl;
result = fread(&filler[0], sizeof(char), MAX_G, userFifo);
if (result < MAX_G) { cout << "read error, usermove" << endl; }
cout << "move read in" << endl;
// catch user move
charInt[0] = filler[6] - '0';
charInt[1] = filler[7] - '0';
cout << charInt[0] << " " << charInt[1] << endl;
// if user says game over, close pipes
if (charInt[0] == 3 && charInt[1] == 3) {
fclose(userFifo);
fclose(serverFifo);
exit(0);
}
// add user move to list of moves
userMoves.push_back(make_pair(charInt[0], charInt[1]));
// mark location of taken moves
untaken[(userMoves.back().first * 3 + userMoves.back().second)] = 0;
// see if game can be ended and add a server move
valid = checkX(userMoves,serverMoves, untaken);
untaken[(serverMoves.back().first * 3 + serverMoves.back().second)] = 0;
//prepare server move for writing
buffer[6] = serverMoves.back().first + '0';
buffer[7] = serverMoves.back().second + '0';
//buffer[0] = -1;
//buffer[1] = -1;
// write servermove to client
//cout << buffer[0] << " " << buffer[1] << endl;
result = fwrite(&buffer[0],sizeof(char),MAX_G,serverFifo);
if (result < MAX_G) { cout << "write error, servermove" << endl; }
}
// close pipes if game is over
fclose(userFifo);
fclose(serverFifo);
exit(0);
}
}
fclose(comms);
return 0;
}