Segmentation fault (core dumped) on Server side in CORBA C++/Java application

问题

I have such code:

interface Employee
{
    string getLastname();
};

#include "Employee.idl"

interface Work
{
    Employee getEmployee(in short id);
};

Server files:

#include "Employee.hh"

class EmployeeImpl : public POA_Employee
{
    private:
        char* lastname;
        int id;

    public:
        EmployeeImpl(const char* lastname, int id);
        char* getLastname();
};

#include "EmployeeImpl.h"

EmployeeImpl::EmployeeImpl(const char* lastname, int id)
{
    this->lastname = const_cast<char*>(lastname);
    this->id = id;
}

char* EmployeeImpl::getLastname()
{
    return this->lastname;
}

#include "Work.hh"
#include <vector>
#include "EmployeeImpl.h"
using namespace std;

class WorkImpl : public POA_Work
{
    private:
        vector<EmployeeImpl> employees;

    public:
        WorkImpl();
        Employee_ptr getEmployee(::CORBA::Short id);
};

#include "WorkImpl.h"

 WorkImpl::WorkImpl()
 {
    EmployeeImpl ei1("Doe", 1);
    EmployeeImpl ei2("Smith", 2);
    EmployeeImpl ei3("Brown", 3);

    employees.push_back(ei1);
    employees.push_back(ei2);
    employees.push_back(ei3);
 }

Employee_ptr WorkImpl::getEmployee(::CORBA::Short id)
{
    return employees[id]._this();
}

Client files:

import java.util.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import java.io.*;

public class Client
{
    public static void main(String [] args)
    {
     try
     {
        org.omg.CORBA.ORB clientORB = org.omg.CORBA.ORB.init(args, null);

        if (clientORB == null)
        {
            System.out.println("Problem while creating ORB");
            System.exit(1);
        }

        org.omg.CORBA.Object objRef = clientORB.resolve_initial_references("NameService");
        NamingContextExt ncRef = NamingContextExtHelper.narrow(objRef);

        Work work = WorkHelper.narrow(ncRef.resolve_str("WorkService"));
        Employee e = work.getEmployee((short)1);
        System.out.println(e.getLastname());
            e = work.getEmployee((short)2);
            System.out.println(e.getLastname());
            e = work.getEmployee((short)3);
            System.out.println(e.getLastname());

        }catch(Exception e){ System.out.println(e.getMessage()); }
    }
}

when I run Server, and then client, on client side I see:

Smith

instead of:

Doe
Smith
Brown

and when the client got the message, on server side I see:

segmentation fault (cope dumped)

and server crashes. Whats wrong with my code guys? I use omniORB and idlj on Kubuntu, and g++ and javac to compile my files.

Heres my whole project: http://www44.zippyshare.com/v/60244821/file.html

回答1:

You aren't following the IDL to C++ mapping rules about parameter passing. In particular, on the server:

char* EmployeeImpl::getLastname()
{
    return this->lastname;   // this is the problem
}

You need to return dynamically allocated memory because the skeleton code is going to deallocate it (with CORBA::string_free) after it marshals it over the wire to the client.

This should be:

char* EmployeeImpl::getLastname()
{
    return CORBA::string_dup(this->lastname);
}

This is all explained in the Henning & Vinowski book Advanced CORBA Programming with C++.

The other problem you are having is you are indexing into your vector with a 1-based index. But vector uses a 0-based index scheme. To fix this, either change your client calls, or change your server implementation to something like this:

Employee_ptr WorkImpl::getEmployee(::CORBA::Short id)
{
    if (id >= 1 && id <= employees.size())
    { 
       return employees[id - 1]._this();  // convert to 0-based indexing
    }
    else
    {
       // throw some type of exception
    }
}

来源：https://stackoverflow.com/questions/12288660/segmentation-fault-core-dumped-on-server-side-in-corba-c-java-application

标签

c++

segmentation-fault

corba

omniorb