Issues writing my Server.c socket maintaining multi threading - c

Question

As the title says, I am creating a server/client connection. The server will allow multiple clients while the clients can communicate with the server. I have both server and client files. I am not sure where I am going wrong.
I execute each line in cygwin
gcc server.c -o server lpthread
crashes :(
gcc client.c -o client
./client localhost 8080
Server.c
#include <stdio.h>
#include <stdlib.h> // for IOs
#include <string.h>
#include <unistd.h>
#include <sys/types.h> // for system calls
#include <sys/socket.h> // for sockets
#include <netinet/in.h> // for internet
#include <stdbool.h>
#include <pthread.h> // for thread;
/* a function to print out error message and then abort */
void error(const char *msg) {
perror(msg);
exit(1);
}
void *threadFunct(int mySockfd) {
char buffer2[256];
bool exitFlag = false;
int read_writeLen;
while(!exitFlag) {
bzero(buffer2, 256);
read_writeLen = read(mySockfd, buffer2, 255);
if (read_writeLen < 0)
printf("ERROR reading from the client socket\n");
if(strcmp(buffer2,"EXIT\n")==0) {
printf("Now socket %d will be close\n", mySockfd);
close(mySockfd);
pthread_exit(mySockfd); // terminate the calling thread
} else {
printf("The message read from socket %d :%s\n ",mySockfd,buffer2);
read_writeLen = write(mySockfd,"I got Your Message" , 18);
if (read_writeLen < 0)
printf("Unable to write to socket\n");
}
}
close(mySockfd);
return NULL;
}
int main(int argc, char *argv[]) {
int sockfd, newsockfd, portno;
socklen_t clilen;
char buffer[256];
struct sockaddr_in serv_addr, cli_addr;
int charRead_Written;
if(argc <2) {
fprintf(stderr, "ERROR, no port provided\n");
exit(1);
}
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(sockfd < 0)
error("ERROR Opening socket");
bzero((char *) &serv_addr, sizeof(serv_addr));
portno = atoi(argv[1]);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(portno);
if(bind(sockfd,(struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
error("ERROR on binding");
while(true) {
pthread_t threadId;
listen(sockfd,10);
clilen = sizeof(cli_addr);
newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
if(newsockfd<0)
error("ERROR on accept");
pthread_create(&threadId,NULL,threadFunct,newsockfd);
}
close(sockfd);
return 0;
}
Client.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <string.h>
#include <stdbool.h>
void error(const char *msg) {
perror(msg);
exit(0);
}
int main(int argc, char *argv[]) {
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;
bool running = false; // Keep running until the user types EXIT
// gcc client.c -o client
// ./client localhost port
char buffer[256];
if (argc <3) {
fprintf(stderr, "usage %s hostname port\n", argv[0]);
exit(0);
}
portno = atoi(argv[2]);
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(sockfd <0)
error("ERROR opening socket");
server = gethostbyname(argv[1]);
if (server == NULL) {
fprintf(stderr, "ERROR , no such host \n");
exit(0);
}
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *) server->h_addr, (char *) &serv_addr.sin_addr.s_addr, server->h_length);
serv_addr.sin_port = htons(portno);
if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) <0)
error("ERROR Connecting");
while(!running) {
printf("Please Enter The message: ");
bzero(buffer, 256);
fgets(buffer, 255, stdin);
n = write(sockfd, buffer, strlen(buffer));
if(n<0)
error("ERROR writing from socket");
if(strcmp(buffer, "EXIT\n")== 0)
{
running = true;
break;
}
bzero(buffer,256);
n = read(sockfd, buffer,255);
if(n < 0)
printf("ERROR reading from socket");
printf("%s\n", buffer);
}
close(sockfd);
return 0;
}
The client.c file compiles and works fine. The server.c file does not compile and not sure how to solve the issues. Posted compile results below for server.c.
server.c: In function ‘threadFunct’:
server.c:39:17: warning: passing argument 1 of ‘pthread_exit’ makes pointer from integer without a cast [-Wint-conversion]
pthread_exit(mySockfd); // terminate the calling thread
^~~~~~~~
In file included from server.c:18:0:
/usr/include/pthread.h:150:6: note: expected ‘void *’ but argument is of type ‘int’
void pthread_exit (void *) __attribute__ ((__noreturn__));
^~~~~~~~~~~~
server.c: In function ‘main’:
server.c:85:36: warning: passing argument 3 of ‘pthread_create’ from incompatible pointer type [-Wincompatible-pointer-types]
pthread_create(&threadId,NULL,threadFunct,newsockfd);
^~~~~~~~~~~
In file included from server.c:18:0:
/usr/include/pthread.h:146:5: note: expected ‘void * (*)(void *)’ but argument is of type ‘void * (*)(int)’
int pthread_create (pthread_t *, const pthread_attr_t *,
^~~~~~~~~~~~~~
server.c:85:48: warning: passing argument 4 of ‘pthread_create’ makes pointer from integer without a cast [-Wint-conversion]
pthread_create(&threadId,NULL,threadFunct,newsockfd);
^~~~~~~~~
In file included from server.c:18:0:
/usr/include/pthread.h:146:5: note: expected ‘void *’ but argument is of type ‘int’
int pthread_create (pthread_t *, const pthread_attr_t *,

Answer 1

Instead of this:
pthread_exit(mySockfd); // terminate the calling thread
This:
pthread_exit(NULL); // terminate the calling thread
Instead of this:
void *threadFunct(int mySockfd)
This:
struct MyArgs
{
int mySockfd;
};
void *threadFunct(void* args)
{
int mySockfd = ((struct MyArgs*)args)->mySockfd;
Then create the thread as follows:
struct MyArgs* args = (struct MyArgs*)malloc(sizeof(struct MyArgs));
args->mySockfd = mySockfd;
pthread_create(&threadId,NULL,threadFunct,(void*)args);
You're on your own to properly invoke free on that allocate structure after the thread has exited or is about to exit.