#include <windows.h>

#include <stdio.h>

#include <stdlib.h>

#pragma hdrstop







#define MAXLEN 256

#define	CHUNK 32







struct Session

{

	char *client; // client machine

	char *user; // user name

	DWORD time; // idle since (seconds)

};







struct SessionList

{

	int nReserved;

	int nUsed; // number of elements

	Session *s; // points to array of Session structs containing the info we want

};







// we do all our declares ourselves. To learn why, check out

// http://www.mvps.org/win32/network/nt95.html







// ----- cut here ----- NT declarations



#define	NET_API_STATUS DWORD

#define	NET_API_FUNCTION __stdcall



typedef NET_API_STATUS (NET_API_FUNCTION *NetSessionEnum_NT)( LPWSTR servername,

	LPWSTR UncClientName, LPWSTR username, DWORD level, LPBYTE *bufptr,

	DWORD prefmaxlen, LPDWORD entriesread, LPDWORD totalentries,

	LPDWORD resume_handle );



typedef NET_API_STATUS (NET_API_FUNCTION *NetApiBufferFree_NT)( LPVOID Buffer );







struct SESSION_INFO_10_NT {

	LPWSTR sesi10_cname;

	LPWSTR sesi10_username;

	DWORD sesi10_time;

	DWORD sesi10_idle_time;

};



// ----- cut here ----- 95 declarations



#define API_FUNCTION DECLSPEC_IMPORT API_RET_TYPE APIENTRY



typedef __declspec(dllimport) DWORD (__stdcall *NetSessionEnum_95)(

	const char FAR *pszServer, short sLevel, char FAR *pbBuffer,

	unsigned short cbBuffer, unsigned short FAR *pcEntriesRead,

	unsigned short FAR *pcTotalAvail );







#pragma pack(push, 1)

struct session_info_0_95 {

	char FAR *sesi0_cname;

};







struct session_info_10_95 {

	char FAR *sesi10_cname;

	char FAR *sesi10_username;

	unsigned long sesi10_time;

	unsigned long sesi10_idle_time;

};







struct session_info_50_95 {

	char FAR *sesi50_cname;

	char FAR *sesi50_username;

	unsigned long sesi50_key;

	unsigned short sesi50_num_conns;

	unsigned short sesi50_num_opens;

	unsigned long sesi50_time;

	unsigned long sesi50_idle_time;

	unsigned char sesi50_protocol;

	unsigned char pad1;

};

#pragma pack(pop)



// ----- cut here ----- End of OS-specific declarations







void FillSessionList95( const char *server, SessionList& sl )

{

	char *buf;

	int bufsize, level, successLevel;

	session_info_10_95 *cur10;

	session_info_50_95 *cur50;

	NetSessionEnum_95 pNSE;

	HINSTANCE hDLL;

	DWORD rc, i;

	WORD read, total;



	hDLL = LoadLibrary( "svrapi.dll" );

	if ( hDLL == NULL )

	{

		printf( "LoadLibrary( \"svrapi.dll\" ): gle = %lu\n", GetLastError() );

		exit( 1 );

	}



	pNSE = (NetSessionEnum_95) GetProcAddress( hDLL, "NetSessionEnum" );

	if ( pNSE == NULL )

	{

		printf( "GetProcAddress( \"svrapi.dll\" ): gle = %lu\n", GetLastError() );

		exit( 1 );

	}



	buf = NULL;

	successLevel = 90;



	// try levels 10 and 50 in this order, until we don't get a level error

	for ( rc = ERROR_INVALID_LEVEL, level = 10;

		rc == ERROR_INVALID_LEVEL && level <= 50; level += 40 )

	{

		bufsize = 1024;

		do

		{

			printf( "Trying: level %d, bufsize = %d bytes\n", level, bufsize );

			free( buf );

			buf = (char *) malloc( bufsize );



			// NOTE: pre-Jul98 Platform SDKs had bugs in the headers

			// and required a cast for the first three args (to char*).



			rc = pNSE( server, level, buf, bufsize, &read, &total );



			// printf( "rc = %ld; server = %s, level = %d, buf = %p, bufsize = %d, read = %d, total = %d\n",

			//	(int) rc, server, level, buf, bufsize, (int) read, (int) total );



			if ( rc == 0 )

				successLevel = level;



			bufsize += 1024;

		} while ( bufsize < 65536 && ( rc == ERROR_MORE_DATA || rc == ERROR_INVALID_PARAMETER ) );

	}



	if ( rc != ERROR_SUCCESS )

	{

		printf( "NSE() returned %lu\n", rc );

		exit( 1 );

	}



	// belts and braces

	if ( successLevel != 10 && successLevel != 50 )

	{

		printf( "why is successLevel == %d?\n", successLevel );

		exit( 1 );

	}



	if ( (DWORD) ( sl.nReserved - sl.nUsed ) < read )

	{

		// make some room in the list

		sl.s = (Session *) realloc( sl.s, ( sl.nReserved + max( CHUNK, read ) ) * sizeof sl.s[0] );

		if ( sl.s == NULL )

		{

			printf( "Unable to get memory for %d additional sessions.\n", max( CHUNK, read ) );

			exit( 1 );

		}

		sl.nReserved += max( CHUNK, read );

	}



	switch ( successLevel )

	{

		case 10:

			for ( i = 0, cur10 = (session_info_10_95 *) buf; i < read; ++ i, ++ cur10 )

			{

				memset( &sl.s[sl.nUsed], '\0', sizeof sl.s[sl.nUsed] );

				if ( cur10->sesi10_cname != NULL )

					sl.s[sl.nUsed].client = strdup( cur10->sesi10_cname );

				if ( cur10->sesi10_username != NULL )

					sl.s[sl.nUsed].user = strdup( cur10->sesi10_username );

				sl.s[sl.nUsed].time = cur10->sesi10_time;

				++ sl.nUsed;

			}

			break;

		case 50:

			for ( i = 0, cur50 = (session_info_50_95 *) buf; i < read; ++ i, ++ cur50 )

			{

				memset( &sl.s[sl.nUsed], '\0', sizeof sl.s[sl.nUsed] );

				if ( cur50->sesi50_cname != NULL )

					sl.s[sl.nUsed].client = strdup( cur50->sesi50_cname );

				if ( cur50->sesi50_username != NULL )

					sl.s[sl.nUsed].user = strdup( cur50->sesi50_username );

				sl.s[sl.nUsed].time = cur50->sesi50_time;

				++ sl.nUsed;

			}

			break;

		default:

			printf( "why is successLevel == %d, and why didn't the "

				"earlier \"if\" catch it?\n", successLevel );

			exit( 1 );

			break;

	}



	FreeLibrary( hDLL );

	free( buf );

}







void FillSessionListNT( const char *server, const char *client, const char *user, SessionList& sl )

{

	SESSION_INFO_10_NT *buf;

	SESSION_INFO_10_NT *cur;

	DWORD read, total, resumeh, rc, i;

	char tt[MAXLEN];

	wchar_t *wserver = NULL, *wclient = NULL, *wuser = NULL;

	NetSessionEnum_NT pNSE = NULL;

	NetApiBufferFree_NT pNABF = NULL;

	HINSTANCE hDLL;



	hDLL = LoadLibrary( "netapi32.dll" );

	if ( hDLL == NULL )

	{

		printf( "LoadLibrary( \"netapi32.dll\" ): gle = %lu\n", GetLastError() );

		exit( 1 );

	}



	pNSE = (NetSessionEnum_NT) GetProcAddress( hDLL, "NetSessionEnum" );

	pNABF = (NetApiBufferFree_NT) GetProcAddress( hDLL, "NetApiBufferFree" );

	if ( pNSE == NULL || pNABF == NULL )

	{

		printf( "GetProcAddress( \"netapi32.dll\" ) returned NULL\n" );

		exit( 1 );

	}



	if ( server != NULL )

	{

		wserver = (wchar_t *) malloc( ( strlen( server ) + 10 ) * 2 );

		mbstowcs( wserver, server, -1 );

	}



	if ( client != NULL )

	{

		wclient = (wchar_t *) malloc( ( strlen( client ) + 10 ) * 2 );

		mbstowcs( wclient, client, -1 );

	}



	if ( user != NULL )

	{

		wuser = (wchar_t *) malloc( ( strlen( user ) + 10 ) * 2 );

		mbstowcs( wuser, user, -1 );

	}



	resumeh = 0;

	do

	{

		buf = NULL;



		// NOTE: pre-Jul98 Platform SDKs had bugs in the headers

		// and required a cast for the first three args (to char*).

		rc = pNSE( wserver, wclient, wuser, 10,

			(BYTE **) &buf, 2048, &read, &total, &resumeh );

		if ( rc != ERROR_MORE_DATA && rc != ERROR_SUCCESS )

			break;



		if ( (DWORD) ( sl.nReserved - sl.nUsed ) < read )

		{

			// make some room in the list

			sl.s = (Session *) realloc( sl.s, ( sl.nReserved + max( CHUNK, read ) ) * sizeof sl.s[0] );

			if ( sl.s == NULL )

			{

				printf( "Unable to get memory for %d additional sessions.\n", max( CHUNK, read ) );

				exit( 1 );

			}

			sl.nReserved += max( CHUNK, read );

		}



		printf( "\ngot %lu entries out of %lu\n", read, total );

		for ( i = 0, cur = buf; i < read; ++ i, ++ cur )

		{

			memset( &sl.s[sl.nUsed], '\0', sizeof sl.s[sl.nUsed] );

			if ( cur->sesi10_cname != NULL )

			{

				wcstombs( tt, cur->sesi10_cname, MAXLEN );

				sl.s[sl.nUsed].client = strdup( tt );

			}

			if ( cur->sesi10_username != NULL )

			{

				wcstombs( tt, cur->sesi10_username, MAXLEN );

				sl.s[sl.nUsed].user = strdup( tt );

			}

			sl.s[sl.nUsed].time = cur->sesi10_time;

			++ sl.nUsed;

		}



		if ( buf != NULL )

			pNABF( buf );



	} while ( rc == ERROR_MORE_DATA );



	FreeLibrary( hDLL );



	if ( rc != ERROR_SUCCESS )

		printf( "NSE() returned %lu\n", rc );



	free( wserver );

	free( wclient );

	free( wuser);

}







void ShowSessionList( const char *server, const char *client, const char *user )

{

	OSVERSIONINFO ovi = { sizeof ovi };

	SessionList sl = { 0, 0, NULL };

	int i;



	GetVersionEx( &ovi );

	switch ( ovi.dwPlatformId )

	{

		case VER_PLATFORM_WIN32_WINDOWS:

			FillSessionList95( server, sl );

			break;

		case VER_PLATFORM_WIN32_NT:

			FillSessionListNT( server, client, user, sl );

			break;

		default:

			puts( "Sorry, but this sample requires Windows 9x or NT." );

			exit( 1 );

	}



	printf( "%-30.30s %-30.30s %-8.8s\n", "Client", "User", "Idle sec" );

	printf( "%-30.30s %-30.30s %-8.8s\n", "------------------------------",

		"------------------------------", "--------" );



	for ( i = 0; i < sl.nUsed; ++ i )

	{

		printf( "%-30.30s %-30.30s %02d:%02d:%02d\n",

			sl.s[i].client == NULL? "": sl.s[i].client,

			sl.s[i].user == NULL? "": sl.s[i].user,

			sl.s[i].time / 3600, ( sl.s[i].time % 3600 ) / 60, sl.s[i].time % 60 );

		free( sl.s[i].client );

		free( sl.s[i].user );

	}



	free( sl.s );

}







int main( int argc, char *argv[] )

{

	const char *server = NULL, *user = NULL, *client = NULL;

	int errors = 0, i;

	bool haveServer = false, haveUser = false, haveClient = false;



	if ( argc > 7 )

	{

usage:

		puts( "\nnsesse2 [-s \\\\server] [-c \\\\computername|-u username]\n" );

		puts( "\\\\server -- machine to check, with backslashes, please." );

		puts( "  Default: local machine.\n" );

		puts( "\\\\computername -- only list sessions from this computer." );

		puts( "  Default: all computers.\n" );

		puts( "username -- only list sessions logged in as username." );

		puts( "  Default: all users.\n" );

		puts( "You can use -c, or -u, or neither -- but not both together." );

		puts( "On Win9X, both -c and -u will be ignored." );

		return 1;

	}



	for ( i = 1; i < argc; ++ i )

	{

		if ( *argv[i] != '-' && *argv[1] != '/' )

		{

			printf( "\"%s\": switches must start with a dash or a slash.\n",

				argv[i] );

			++ errors;

			continue;

		}



		switch ( argv[i][1] )

		{

			case '?':

				goto usage;

			case 's':

				if ( i == argc - 1 ) // no further args?

				{

					printf( "\"%s\" requires the server name as an argument.\n", argv[i] );

					++ errors;

					break;

				}

				if ( haveServer )

				{

					printf( "\"%s\" can only be used once.\n", argv[i] );

					++ errors;

					++ i; // skip what probably is another server name

					break;

				}

				++ i; // advance arg index to account for server name

				server = argv[i];

				haveServer = true;

				break;

			case 'c':

				if ( i == argc - 1 ) // no further args?

				{

					printf( "\"%s\" requires the client name as an argument.\n", argv[i] );

					++ errors;

					break;

				}

				if ( haveClient )

				{

					printf( "\"%s\" can only be used once.\n", argv[i] );

					++ i;

					++ errors;

					break;

				}

				++ i;

				client = argv[i];

				haveClient = true;

				if ( client[0] != '\\' || client[1] != '\\' )

				{

					printf( "\"%s\" should start with a double backslash \"\\\\\".\n", client );

					++ errors;

				}

				break;

			case 'u':

				if ( i == argc - 1 ) // no further args?

				{

					printf( "\"%s\" requires the user name as an argument.\n", argv[i] );

					++ errors;

					break;

				}

				if ( haveUser )

				{

					printf( "\"%s\" can only be used once.\n", argv[i] );

					++ i;

					++ errors;

					break;

				}

				++ i;

				user = argv[i];

				haveUser = true;

				break;

			default:

				printf( "\"%s\" is not a valid switch, sorry.\n", argv[i] );

				++ errors;

				break;

		}

	}



	if ( errors )

	{

		printf( "\n%d command line errors. Pass GO, do not collect $200.\n\n",

			errors );

		goto usage;

	}



	ShowSessionList( server, client, user );



	return i;

}