Encountering seg fault in wininet ftp program - c++

Question

So i found this c++ program and i thought i would use it to automate backing up my files to my desktop ftp server but it always runs into the same seg fault problem, After checking the ftp server logs i can see that is does actually connect to the ftp server and log in with the user name and password but it when it reaches the actual upload part it crashes.
I ran it through the debugger in dev c++ and it says "Access violation (Seg faut)"
Is this a bug in wininet? and if so is there some sort of workaround?
#include <windows.h>
#include <wininet.h>
#pragma comment(lib, "wininet")
#include <fstream>
#include <string.h>
int send(const char * ftp, const char * user, const char * pass, const char * pathondisk, char * nameonftp)
{
HINTERNET hInternet;
HINTERNET hFtpSession;
hInternet = InternetOpen(NULL,INTERNET_OPEN_TYPE_DIRECT,NULL,NULL,0);
if(hInternet==NULL)
{
cout << GetLastError();
//system("PAUSE");
return 1;
}
hFtpSession = InternetConnect(hInternet,
(LPTSTR)ftp, INTERNET_DEFAULT_FTP_PORT,
(LPTSTR)user, (LPTSTR)pass, INTERNET_SERVICE_FTP,
INTERNET_FLAG_PASSIVE, 0);
if(hFtpSession==NULL)
{
cout << GetLastError();
//system("PAUSE");
return 1;
}
Sleep(1000);
char * buf=nameonftp;
strcat(buf,".txt");
if (!FtpPutFile(hFtpSession, (LPTSTR)pathondisk, (LPTSTR)buf, FTP_TRANSFER_TYPE_ASCII, 0)) {
cout << GetLastError();//this is never reached
return 1;
}
Sleep(1000);
InternetCloseHandle(hFtpSession);
InternetCloseHandle(hInternet);
return 0;
}
int main() {
send("127.0.0.1","testuser","test","file.pdf","backup");
return 0;
}

Answer 1

You must not modify string literals. Copy the string to a new buffer to edit the contents.
Also, you should use hogeA() APIs to have the system use ANSI charset explicitly.
Try this:
#include <windows.h>
#include <wininet.h>
#pragma comment(lib, "wininet")
#include <iostream>
#include <fstream>
#include <string.h>
using std::cout;
int send(const char * ftp, const char * user, const char * pass, const char * pathondisk, const char * nameonftp)
{
HINTERNET hInternet;
HINTERNET hFtpSession;
hInternet = InternetOpen(NULL, INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
if(hInternet==NULL)
{
cout << GetLastError();
//system("PAUSE");
return 1;
}
hFtpSession = InternetConnectA(hInternet,
ftp, INTERNET_DEFAULT_FTP_PORT,
user, pass, INTERNET_SERVICE_FTP,
INTERNET_FLAG_PASSIVE, 0);
if(hFtpSession==NULL)
{
cout << GetLastError();
//system("PAUSE");
return 1;
}
Sleep(1000);
char * buf=new char[strlen(nameonftp) + 4 + 1];
strcpy(buf, nameonftp);
strcat(buf, ".txt");
if (!FtpPutFileA(hFtpSession, pathondisk, buf, FTP_TRANSFER_TYPE_ASCII, 0)) {
cout << GetLastError();
delete[] buf;
return 1;
}
delete[] buf;
Sleep(1000);
InternetCloseHandle(hFtpSession);
InternetCloseHandle(hInternet);
return 0;
}
int main() {
send("127.0.0.1", "testuser", "test", "file.pdf", "backup");
return 0;
}