Programming

 
#include "../hdr/isamhdr.h" 
#include <mcheck.h>
 
int main(int argc, char *argv[]) 
{
    struct addrinfo hints, *res, *p;
    struct sockaddr *accepted_conc;
    int status, socket_fd,accept_fd,sockaddr_size=sizeof(accepted_conc),curr_conc=0,max_conc;
    pthread_t *threads;

    if(argc != 3)
    {
        printf("ITF_ERR: Usage %s <port numebr> <max_connections>\n",argv[0]);
        return 2;
    }

    max_conc=atoi(argv[2]);
    threads=calloc(max_conc,sizeof(pthread_t));
    accepted_conc=calloc(max_conc,sizeof(struct sockaddr));

    memset(&hints, 0, sizeof hints);

    hints.ai_family = AF_UNSPEC; 
    hints.ai_socktype = SOCK_STREAM;    // open tcp connection
    hints.ai_flags = AI_PASSIVE;                // server always runs on localhost


    if ((status = getaddrinfo(NULL,argv[1], &hints, &res)) != 0) 
    {
        printf("ITF_ERR: getaddrinfo():%s\n", gai_strerror(status));
        return 2;
    }
    // socket()
    if((socket_fd = socket(res->ai_family,res->ai_socktype,res->ai_protocol)) <0 )
    {
        printf("ITF_ERR: socket() %s\n",strerror(errno));
        return 2;
    }
    else
        printf("socket() call sucess\n");
    
    // bind()
    if((status = bind(socket_fd,res->ai_addr,res->ai_addrlen)) < 0)
    {
        printf("ITF_ERR: bind() %s\n",strerror(errno));
        return 2;
    }
    else
        printf("bind() call sucess\n");

    // listen()
    if((status = listen(socket_fd,10)) < 0)
    {
        printf("ITF_ERR: listen() %s\n",strerror(errno));
        return 2;
    }
    else
        printf("listen() call success\n");

    while(curr_conc < max_conc)
    {
        printf("waiting for new connections ...\n");
        // accept()
        if((accept_fd = accept(socket_fd,accepted_conc+curr_conc,&sockaddr_size)) <0 )
        {
            printf("ITF_ERR: accept() %s\n",strerror(errno));
            return 2;
        }
        else
        {
            curr_conc++;
            printf("%d -accept() call success\n",curr_conc);
        }
        status = pthread_create(&threads[curr_conc], NULL,_server_thread, (void *)accept_fd);
        if(status)
        {
            printf("ITF_ERR; return code from pthread_create() is %d\n", status);
            return 2;
        }
    }
    close(socket_fd);
    printf("no room for further threads\n");
    
    return 0; 
} 
 
void *_server_thread(void *sock_fd)
{ 
    void *lib_hdl; 
    USR_qry_ptr qry; 
    USR_rslt_set_ptr rslt; 
    unsigned char qry_str[LINE_MAX];
    int fd=(int)sock_fd,sts;

    if((lib_hdl=dlopen(ISAM_LIB,RTLD_NOW)) == NULL) 
    { 
        printf("%s\n",dlerror()); 
        return NULL; 
    } 
 
    dl_qry_parser=dlsym(lib_hdl,"qry_parser"); 
     
    if(dl_qry_parser == NULL) 
    { 
        printf("%s\n",dlerror()); 
        return NULL; 
    } 
    dl_execute_qry=dlsym(lib_hdl,"execute_qry"); 
     
    if(dl_execute_qry == NULL) 
    { 
        printf("%s\n",dlerror()); 
        return NULL; 
    } 
    dl_print_rslt_set=dlsym(lib_hdl,"_print_rslt_set"); 
     
    if(dl_print_rslt_set == NULL) 
    { 
        printf("%s\n",dlerror()); 
        return NULL; 
    }
    dl_free_rslt_set=dlsym(lib_hdl,"_free_rslt_set"); 
     
    if(dl_free_rslt_set == NULL) 
    { 
        printf("%s\n",dlerror()); 
        return NULL; 
    }
    
    dl_free_qry=dlsym(lib_hdl,"_free_qry"); 
     
    if(dl_free_qry == NULL) 
    { 
        printf("%s\n",dlerror()); 
        return NULL; 
    }
    
    
    while(1)
    {
        sts=recv(fd,qry_str,LINE_MAX,0);
        if(sts < 0)
        {
            printf("SRV_ERR: recv() %s\n",strerror(errno));
            close(fd);
            pthread_exit(NULL);
        }            
        if(!strcmp(qry_str,"quit"))
        {
            printf("SRV_ERR: Thread exiting by quit\n");
            close(fd);
            pthread_exit(NULL);
        }
    
        qry=(*dl_qry_parser)((unsigned char *)qry_str);        
        rslt=(*dl_execute_qry)(qry);

        (*dl_print_rslt_set)(rslt);

        // do clean up        
        (*dl_free_rslt_set)(rslt);
        (*dl_free_qry)(qry);
    }

    return NULL;
}