C program only write into files when debugging - c

Question

I am writing a simple code to test thread pools. I have a client sendin lines of data to server through different ports.
Some threads receive the data, then send them to other threads for processing.
For now, the only processing I am doing is just to write the data into a file.
Here is the code of the worker thread.
void* worker_thread(void* arg){
int i, workerNum;
pthread_t worker_id = pthread_self();
char *ticket = (char*) arg;
char dumpfile[50];
for(i=0;i<10;i++)
if(pthread_equal(worker_id, id_pool[i]))
break;
if(10==i){
pthread_exit(NULL);
}
workerNum = i;
fprintf(stdout, "Worker [%d] busy\n",workerNum);
sprintf(dumpfile, "worker_%d.log",workerNum);
if(strlen(ticket)<4){
fprintf(stdout, "Worker [%d] RELEASED!!\n",workerNum);
poolStatus[workerNum] = 0;
pthread_mutex_unlock(&mutexes[workerNum]);
pthread_exit(NULL);
}
FILE *logFile = fopen(dumpfile, "a+");
// ticket[strlen(ticket)]
fprintf(logFile, "%s\n", ticket);
fclose(logFile);
sleep(workerNum+2);
poolStatus[workerNum] = 0;
fprintf(stdout, "Worker [%d] RELEASED!!\n",workerNum);
pthread_mutex_unlock(&mutexes[workerNum]);
pthread_exit(NULL);
}
The code works when I run through a debugger (GDB, under linux). When I run it simply on the command line, it runs but does not create the files!
Can you please assist?
the complete code:
#include <time.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <strings.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define BUFSIZE 65535
#define NUMWORKERS 10
static pthread_mutex_t mutexes[NUMWORKERS];
pthread_t id_pool[NUMWORKERS], id_servers[6];
int serverports[6] = {22191, 22192, 22193, 7525, 7526, 7527};
char poolStatus[NUMWORKERS] = {0};
void error(char *msg) {
FILE *logFile = fopen("errorlog.log", "a+");
fprintf(logFile, "%s\n", msg);
fclose(logFile);
exit(1);
}
void* serverListener(void* arg);
void* worker_thread(void* arg);
int main(){
int i, t_err[6];
for(i=0; i< NUMWORKERS; i++)
pthread_mutex_init(&mutexes[i],NULL);
for(i=0; i<6; i++){
t_err[i] = pthread_create(&id_servers[i], NULL, serverListener, NULL);
}
pthread_join(id_servers[5], NULL);
return 0;
}
void* serverListener(void* arg){
int parentfd, childfd; // parent socket & child socket
int portno, clientlen; // port number and size of client address
struct sockaddr_in serveraddr;
struct sockaddr_in clientaddr;// server and client addresses
struct hostent *hostp; // client host info
char buf[BUFSIZE]; // message buffer
char *hostaddrp; // dotted decimal host addr string
int optval, n; // flag value for setsockopt and message byte size
unsigned int CLOCKREF, CLOCKCOUNT;
pthread_t id = pthread_self(); // own thread id
int threadNumber, i=0; // thread number linked to ort to listen to.
char dumpfile[50];
for(i=0; i<6; i++) if(pthread_equal(id, id_servers[i])) break;
threadNumber = i;
portno = serverports[threadNumber];
sprintf(dumpfile, "receiver_%d.log",portno);
// socket: create the parent socket
parentfd = socket(AF_INET, SOCK_STREAM, 0);
if (parentfd < 0)
error("ERROR opening socket");
optval = 1;
setsockopt(parentfd, SOL_SOCKET, SO_REUSEADDR, (const void *)&optval , sizeof(int));
// build the server's Internet address
bzero((char *) &serveraddr, sizeof(serveraddr));
serveraddr.sin_family = AF_INET;
// let the system figure out our IP address
serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
// this is the port we will listen on
serveraddr.sin_port = htons((unsigned short)portno);
// bind: associate the parent socket with a port
if (bind(parentfd, (struct sockaddr *) &serveraddr,
sizeof(serveraddr)) < 0)
error("ERROR on binding");
// listen: make this socket ready to accept connection requests
if (listen(parentfd, 5) < 0) /* allow 5 requests to queue up */
error("ERROR on listen");
// main loop: wait for a connection request
clientlen = sizeof(clientaddr);
while (1) {
// accept: wait for a connection request
childfd = accept(parentfd, (struct sockaddr *) &clientaddr, &clientlen);
if (childfd < 0)
error("ERROR on accept");
// gethostbyaddr: determine who sent the message
hostp = gethostbyaddr((const char *)&clientaddr.sin_addr.s_addr,
sizeof(clientaddr.sin_addr.s_addr), AF_INET);
if (hostp == NULL)
error("ERROR on gethostbyaddr");
hostaddrp = inet_ntoa(clientaddr.sin_addr);
if (hostaddrp == NULL)
error("ERROR on inet_ntoa\n");
fprintf(stdout, "server established connection with %s (%s)\n", hostp->h_name, hostaddrp);
// read: read input string from the client
CLOCKREF = (unsigned int)time(NULL);
int counter = 0;
while(1){
CLOCKCOUNT = (unsigned int)time(NULL) - CLOCKREF;
bzero(buf, BUFSIZE);
n = read(childfd, buf, BUFSIZE);
if (n < 0) error("ERROR reading from socket");
if(0==n) counter++;
if(3<=counter) {
close(childfd);
return;
}
int busyWorker = 1;
i = 0;
while(busyWorker){
if(i>=NUMWORKERS) i = 0;
if(pthread_mutex_trylock(&mutexes[i])==0){ // not locked, can be used
fprintf(stdout, "port [%d] sends to thread [%d]\n", portno, i);
pthread_create(&id_pool[i], NULL, worker_thread, (void*)buf);
busyWorker = 0;
break;
}
i++;
}
}
close(childfd);
}
}
void* worker_thread(void* arg){
int i, workerNum;
pthread_t worker_id = pthread_self();
char *ticket = (char*) arg;
char dumpfile[50];
for(i=0;i<10;i++)
if(pthread_equal(worker_id, id_pool[i]))
break;
if(10==i){
pthread_exit(NULL);
}
workerNum = i;
fprintf(stdout, "Worker [%d] busy\n",workerNum);
sprintf(dumpfile, "worker_%d.log",workerNum);
if(strlen(ticket)<4){
fprintf(stdout, "Worker [%d] RELEASED!!\n",workerNum);
poolStatus[workerNum] = 0;
pthread_mutex_unlock(&mutexes[workerNum]);
pthread_exit(NULL);
}
FILE *logFile = fopen(dumpfile, "a+");
// ticket[strlen(ticket)]
fprintf(logFile, "%s\n", ticket);
fclose(logFile);
sleep(workerNum+2);
poolStatus[workerNum] = 0;
fprintf(stdout, "Worker [%d] RELEASED!!\n",workerNum);
pthread_mutex_unlock(&mutexes[workerNum]);
pthread_exit(NULL);
}

Answer 1

I believe I have found the problem!!
To pass a message from serverListener thread to worker_thread, I used the pointer to buffer used to read from the socket. Problem is, before the worker_thread could process it, the serverListener has reset the value to zero ( bzero(buf, BUFSIZE) ) ! and given the fact that the worker_thread must only write to file when the size is greater than 4, it doesn't write it.
so to solve my problem, I replaced the line:
pthread_create(&id_pool[i], NULL, worker_thread, (void*)buf);
by:
char *msg2send = strdup(buf);
pthread_create(&id_pool[i], NULL, worker_thread, (void*)msg2send);
And it did the trick!!
Still does not really explain why it could create the files in debug mode though...