Unable to get command line info from PEB

#include <pstypes.h>

#include <psfuncs.h>

static LPWSTR

getCommandLineFromProcess(HANDLE hProcess)

{

    PEB peb;

    PROCESS_BASIC_INFORMATION info;

    RTL_USER_PROCESS_PARAMETERS Params;

    NtQueryInformationProcess(hProcess, ProcessBasicInformation, &info, sizeof(info), NULL);

    ReadProcessMemory(hProcess, info.PebBaseAddress, &peb, sizeof(peb), NULL);

    ReadProcessMemory(hProcess, peb.ProcessParameters, &Params, sizeof(Params), NULL);

    LPWSTR cmdline = Params.CommandLine.Buffer;

    SIZE_T cchCmdLine = Params.CommandLine.Length;

    LPWSTR pszBuffer = (LPWSTR)calloc(cchCmdLine + 1, sizeof(WCHAR));

    ReadProcessMemory(hProcess, cmdline, pszBuffer, cchCmdLine, NULL);

    pszBuffer[cchCmdLine] = UNICODE_NULL;

    return pszBuffer; // needs free()

}