Windows Netapi32 - c++

Question

I am currently accessing the Windows Netapi32 using Netapi32.lib, currently I am using c++ to access the api. I am having trouble retrieving the computer name, currently one the NetFileEnum here on FILE_INFO_3 structure here. In the documentation it says,
fi3_username
Pointer to a string that specifies which user (on servers that have user-level security) or which computer (on servers that have
share-level security) opened the resource. Note that Windows does not
support share-level security.This string is Unicode if _WIN32_WINNT or FORCE_UNICODE are defined.
Now, the network that I am running this script in has indeed Share-level security, I am just not sure how to list the computer name.
Relevant code
Library includes:
#pragma comment(lib, "Netapi32.lib")
#include <stdio.h>
#include <assert.h>
#include <windows.h>
#include <lm.h>
Initiate structure:
fstatus is defined in my code as, NET_API_STATUS fStatus, it is the I/O structure. Documentation here
if fstatus is successful the Return value NERR_Success.
If the function fails, the return value can be one of the following error codes.
ERROR_ACCESS_DENIED The user does not have access to the requested
information.
ERROR_INVALID_LEVEL The value specified for the level parameter is
not valid.
ERROR_INVALID_PARAMETER The specified parameter is not valid.
ERROR_MORE_DATA More entries are available. Specify a large enough buffer to receive all entries.
....
more here
To handle that I use if ((fStatus == NERR_Success) || (fStatus == ERROR_MORE_DATA))
The user name could not be found.
fStatus = NetFileEnum(
flServerName, //Pointer to a string that specifies the DNS or NetBIOS name of the remote server on which the function is to execute. If this parameter is NULL, the local computer is used.
flBasePath, //Pointer to a string that specifies a qualifier for the returned information. If this parameter is NULL, all open resources are enumerated.
flUserName, //Pointer to a string that specifies the name of the user or the name of the connection.
dfLevel, //Pointer to a string that specifies the name of the user or the name of the connection. Can be either 2 or 3, I am using 3
(LPBYTE*)&pFile, //Pointer to the address of the buffer that receives the information. The format of this data depends on the value of the level parameter.
fwPrefMaxLen, //pecifies the preferred maximum length of returned data, in bytes.
&fwEntriesRead, //Pointer to a value that receives the count of elements actually enumerated.
&fwTotalEntries, //Pointer to a value that receives the total number of entries that could have been enumerated from the current resume position.
&fwResumeHandle); //Pointer to a value that contains a resume handle which is used to continue an existing file search.
NET_API_STATUS NetFileEnum(
_In_ LMSTR servername,
_In_ LMSTR basepath,
_In_ LMSTR username,
_In_ DWORD level,
_Out_ LPBYTE *bufptr,
_In_ DWORD prefmaxlen,
_Out_ LPDWORD entriesread,
_Out_ LPDWORD totalentries,
_Inout_ PDWORD_PTR resume_handle
);
RAW Values for the above:
NET_API_STATUS fStatus;
LPFILE_INFO_3 pFile = NULL;
LPFILE_INFO_3 pTmpFile;
DWORD dfLevel = 3;
LPTSTR flServerName = NULL;
LPTSTR flUserName = NULL;
LPTSTR flBasePath = NULL;
DWORD fwPrefMaxLen = MAX_PREFERRED_LENGTH;
DWORD fwEntriesRead = 0;
DWORD fwTotalEntries = 0;
DWORD fwResumeHandle = 0;
pTmpfile is the level 3 (documentation here) buffer object,
bufptr [out]
Pointer to the address of the buffer that receives the information. The format of this data depends on the value of the levelparameter.
This buffer returns data in this format,
typedef struct _FILE_INFO_3 {
DWORD fi3_id;
DWORD fi3_permissions;
DWORD fi3_num_locks;
LMSTR fi3_pathname;
LMSTR fi3_username;
} FILE_INFO_3, *PFILE_INFO_3, *LPFILE_INFO_3;
Retrieve data:
printf("\n\tComputer: %S\n", pTmpFile->fi3_username); //how do I retrieve computer name???
printf("\n\tid: %D\n", pTmpFile->fi3_id);
printf("\n\tpath: %S\n", pTmpFile->fi3_pathname);
**It is important to note that I have tried this using vbnet and it works, but somehow cant figure it how to do it on c++.
Complete Test Program:
#ifndef UNICODE
#define UNICODE
#endif
//Initialize the NetAPI Library
#pragma comment(lib, "Netapi32.lib")
#include <stdio.h>
#include <assert.h>
#include <windows.h>
#include <lm.h>
int wmain(int argc, wchar_t *argv[])
{
//NetFile Enum, using 3 Level.
NET_API_STATUS fStatus;
LPFILE_INFO_3 pFile = NULL;
LPFILE_INFO_3 pTmpFile;
DWORD dfLevel = 3;
LPTSTR flServerName = NULL;
LPTSTR flUserName = NULL;
LPTSTR flBasePath = NULL;
DWORD fwPrefMaxLen = MAX_PREFERRED_LENGTH;
DWORD fwEntriesRead = 0;
DWORD fwTotalEntries = 0;
DWORD fwResumeHandle = 0;
DWORD fi;
//
// Check command line arguments.
// Dont need this currently.
//
do
{
fStatus = NetFileEnum(flServerName,
flBasePath,
flUserName,
dfLevel,
(LPBYTE*)&pFile,
fwPrefMaxLen,
&fwEntriesRead,
&fwTotalEntries,
&fwResumeHandle);
if ((fStatus == NERR_Success) || (fStatus == ERROR_MORE_DATA))
{
if ((pTmpFile = pFile) != NULL)
{
for (fi=0; fi < fwEntriesRead; fi++)
{
assert(pTmpFile != NULL);
if (pTmpFile == NULL)
{
fprintf(stderr, "An access violation has occurred\n");
break;
}
printf("\n\tComputer: %S", pTmpFile->fi3_username);
printf("\n\tid: %d", pTmpFile->fi3_id);
printf("\n\tpath: %s", pTmpFile->fi3_pathname);
printf("\n\tLocks: %d\n", pTmpFile->fi3_num_locks);
pTmpFile++;
fwTotalEntries++;
}
}
}
else
fprintf(stderr, "A system error has occurred: %d\n", fStatus);
//
// Free the allocated memory.
//
if (pFile != NULL)
{
NetApiBufferFree(pFile);
pFile = NULL;
}
}
//
// Continue to call NetFilEnum while
// there are more entries.
//
while (fStatus == ERROR_MORE_DATA);
if (pFile != NULL)
NetApiBufferFree(pFile);
return 0;
}
Output:
From Build:
1>------ Build started: Project: Perfmon, Configuration: Release Win32 ------
1>Compiling...
1>file_enumerate.cpp
1>Linking...
1>Generating code
1>Finished generating code
1>Embedding manifest...
1>Build log was saved at "file://...."
1>Perfmon - 0 error(s), 0 warning(s)
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========
Run:
Computer: User1 //prints only username, not computername (in our system, each user has the same username)
id: 1005687
path: c:\fips\library
Computer: User2 //prints only username, not computername (in our system, each user has the same username)
id: 1005689
path: c:\fips\library\util

Answer 1

If anyone else is wondering about the solution, I figured it out. To query the number of files assoicated with the Computer and not just the User, the NetFileEnum function has to be used, documentation here. The NetFileEnum syntax is shown below,
NET_API_STATUS NetFileEnum(
_In_ LMSTR servername,
_In_ LMSTR basepath,
_In_ LMSTR username,
_In_ DWORD level,
_Out_ LPBYTE *bufptr,
_In_ DWORD prefmaxlen,
_Out_ LPDWORD entriesread,
_Out_ LPDWORD totalentries,
_Inout_ PDWORD_PTR resume_handle
);
Where you have to pass the Computer Name as LMSTR username (you can retrieve the computer name by quering NetSessionEnum(502) which will return all computer names in the network, documentation here ) and the query returns the file details based on the DWORD level, either FILE_INFO_3 documentation here and FILE_INFO_2 documentation here.