Fork and MySQL causing infine loop

Hi,

I am creating a socket application that requires connecting a MySQL database.

Basically, I am accepting a socket, forking the process, then calling a method to perform user authentication. Everything works fine, however, if I manually break the connection on the client end, the programs runs into an infinite loop.

The code is listed below:

server.c

Code:

#include <stdio.h>
#include "server.h"
#include "prompt.h"
#include "single_transaction.h"
#include "logging.h"
#include <signal.h>
#include "permissions.h"

void initChild(int client, SSL_CTX* ctx);

void error(const char *msg) {
	perror(msg);
	exit(1);
}

int main(int count, char *strings[])
{   SSL_CTX *ctx;
	int server, client_sockfd;
    char *portnum;
	int pid;
    if ( count != 2 )
    {
        printf("Usage: %s <portnum>\n", strings[0]);
        exit(0);
    }
	SSL_library_init();
    portnum = strings[1];
	ctx = InitServerCTX();											/* initialize SSL */  
  	LoadCertificates(ctx, "../keys/mycert.pem", "../keys/server.key");	/* load certs */
    server = OpenListener(atoi(portnum));							
	struct sockaddr_in addr;
	int len = sizeof(addr);							
	signal(SIGCHLD, SIG_IGN); /* Prevent zombie processes */
	while (1) {
		if ((client_sockfd = accept(server,(struct sockaddr *)&addr,&len)) == -1) {
			/** accept error **/
		         exit(1);
		}
		if (!(pid = fork())) {
			/** Child keeps communicating here **/
			initChild(client_sockfd, ctx);
			/** Now Child Exits **/
		    shutdown(client_sockfd,2);
		    close(client_sockfd);
		}
		 /** if forked successfully **/
		//close(client_sockfd ); /* Causes socket to close - the socket should be closed by the client */	
	}  /** while waiting for hits on port **/
	close(server);
	SSL_CTX_free(ctx);	

	return 0;
}
void initChild(int client, SSL_CTX* ctx) {
	int sd, response, n;
	char action[255];
	int bufsize = 1024;
	char* buf = (char *)malloc(1024*sizeof(char));
	SSL ........l;
	ssl = SSL_new(ctx);         									/* get new SSL state with context */	
	SSL_set_fd(ssl, client);										/* set connection socket to SSL state */
	if ( SSL_accept(ssl) == FAIL )					/* do SSL-protocol accept */
        ERR_print_errors_fp(stderr);
    else
    {
		if(authenticate_client("ethanhayon", "password")) {
			while (1)
			{
				write_menu(ssl);
				printf("Action: %d\n", getAction(ssl));
			
			}	
		}
	}
	

	/* clean up */	
	free(buf);
	sd = SSL_get_fd(ssl);											/* get socket connection */
    SSL_free(ssl);													/* release SSL state */
    close(sd);	
																	/* close connection */
	
}

permissions.h

Code:

#include <my_global.h>
#include <mysql.h>

#ifndef _PERMISSIONS_H_
#define _PERMISSIONS_H_

int authenticate_client(char * username, char * password) {
	MYSQL *conn;
	MYSQL_RES *result;
	int num_rows;
	char* query = (char *)malloc(1024*sizeof(char));
	conn = mysql_init(NULL);
	if (!(mysql_real_connect(conn, "localhost", "user", "pass", "db_name", 0, NULL, 0))) {
		printf("Error connecting to database");
		// exit gracefully
	} else {
		sprintf(query, "SELECT * FROM permissions WHERE username='%s' AND password = '%s'", username, password);
		mysql_query(conn, "SELECT * FROM permissions WHERE username = 'ethanhayon'");
		result = mysql_store_result(conn);
		num_rows = mysql_num_rows(result);
	}
  	// clean up...
	mysql_free_result(result);
	mysql_close(conn);
	free(query);
	return 1;
	
}

Any help is appreciated!

Thank you!

- Ethan

EDIT: I know the code is messy, I'm still in the debugging phase...

Well, right off the top, you should not be writing code in header files... make a C file for the code and an H file with prototypes only.

Thank you, I plan to change that. This is for debug purposes only.

Why not run it in a debugger and see where the infinite loop is?

Thanks! I was able to pinpoint what was causing it. It was the mysql_real_connect().
I fixed it by using the "CLIENT_IGNORE_SIGPIPE" flag with mysql_real_connect().