/*******
--About nosparse.cpp--
Preventing fragmentation of ".vmem" file of VMware Server 1.0.x on Linux(32 or 64bit)
Generating .vmem file as a normal file, not as a sparse file.

This code is based on the "hook_tcp.cpp" by Yoggy(http://www.t-dori.net/?hook_tcp.so) 
Special thanx to Yoggy and Team t-dori!

--How to use--
Compile:
***!! you need to compile this code on the 32 bit Linux box !!***
g++ -Wall -fPIC  -shared -o nosparse.so nosparse.cpp -ldl

Run:
example_shell> LD_PRELOAD=/root/vmware/nosparse.so /usr/lib/vmware/bin/vmware-vmx -x -C /vmware/Linux/Linux.vmx -@ \"\" &
Suppose "nosparse.so" is on /root/vmware and your guest .vmx file is /vmware/Linux/Linux.vmx
Your guest OS needs at least more than 200MB memory allocated.
Generating .vmem file takes some time. Please be patient.

Author: Kanatoko<anvil@jumperz.net>
http://www.jumperz.net/
*******/

#include <dlfcn.h>
#include <syslog.h>
#include <fstream>

#if defined(RTLD_NEXT)
#define REAL_LIBC RTLD_NEXT
#else
#define REAL_LIBC ((void *) -1L)
#endif

using namespace std;

static int flag1 = 0;

// pointer to the original function
static int (*original_pwrite64) (int file_descriptor, const void *buf, size_t nbyte, off64_t offset) = NULL;

// for logging
#define LOG(...) do {                 \
  syslog(LOG_INFO, __VA_ARGS__);      \
} while(0)

#define SADDR_B(target,shift)  (((target) >>  (shift)) & 0x000000ff)

static void __attribute__ ((constructor))
_constructor()
{
  // for syslog
  openlog(NULL, LOG_CONS | LOG_NDELAY | LOG_PID, LOG_USER); 

  //get address of the original function
  original_pwrite64 = (int(*)(int,const void*,size_t, off64_t)) dlsym(REAL_LIBC, "pwrite64");
}

static void __attribute__ ((destructor))
_destructor()
{
  closelog();
}

ssize_t pwrite64(int fd, const void *buf, size_t nbyte, off64_t offset)
{
int rv;
if( flag1 == 0
 && offset > ( 1024 * 1024 * 200 ) //works only if offset is larger than 200MB
 && nbyte == 1
  )
	{
	flag1 = 1;
	LOG( "pwrite64 is hooked. ARGS: nbyte=%d, offset=%d\n", nbyte, (int)offset );
	LOG( "creating .vmem file...\n" );
	int bufsize = 1024 * 1024;
	char buffer[ bufsize ];
	off64_t remain = offset + 1;

	while( remain > 0 )
		{
		if( remain > bufsize )
			{
			rv = write( fd, buffer, bufsize );
			}
		else
			{
			rv = write( fd, buffer, remain );
			}
		if( rv == -1 )
			{
			LOG( "write failed.\n" );
			return -1;
			}
		remain -= rv;
		}
	return 1;
	}
else
	{
	rv = (*original_pwrite64)(fd, buf, nbyte, offset );
	return rv;
	}
}