Re: [boost] [boost.process] Review

Subject: Re: [boost] [boost.process] Review
From: Klemens Morgenstern (klemens.morgenstern_at_[hidden])
Date: 2016-10-24 18:31:13

Am 24.10.2016 um 23:58 schrieb Remi Chateauneu:
> "Get the parent process id ?"
>
> I found and successfully tested this on Windows 7:
> http://stackoverflow.com/questions/185254/how-can-a-win32-process-get-the-pid-of-its-parent
>
> ULONG_PTR GetParentProcessId() // By Napalm @ NetCore2K{
>   ULONG_PTR pbi[6];
>   ULONG ulSize = 0;
>   LONG (WINAPI *NtQueryInformationProcess)(HANDLE ProcessHandle, ULONG
> ProcessInformationClass,
>    PVOID ProcessInformation, ULONG ProcessInformationLength, PULONG
> ReturnLength);
>   *(FARPROC *)&NtQueryInformationProcess =
>    GetProcAddress(LoadLibraryA("NTDLL.DLL"), "NtQueryInformationProcess");
>   if(NtQueryInformationProcess){
>    if(NtQueryInformationProcess(GetCurrentProcess(), 0,
>      &pbi, sizeof(pbi), &ulSize) >= 0 && ulSize == sizeof(pbi))
>       return pbi[5];
>   }
>   return (ULONG_PTR)-1;}
>
>
Neat. I hope you don't have a problem, if I do in fact consider that not 
straight-forward. Though to be fair, I had code like that in my library 
too, before I realized that the particular problem was easier to solve. 
Not sure however, why the function returns a pointer.
It's also a bit ugly, since the Nt* functions have errorcodes different 
from the regular API functions - and you can run into a number of access 
right errors here.

Well the review starts on thursday, so considering, that I might still 
get an urgent bugfix and have a dayjob, I'd think that's to little time 
to get a solid version into the library. We'll do it afterwards, but 
this shouldn't be a problem. So you'd have two functions:

child::get_parent_id();
this_process::get_parent_id();

If you want to help me out here, the pattern is this: Implementation in 
boost::process::detail::windows/posix, two times, on that throws, one 
that uses std::error_code, and then using them in the higher layer 
though the namespace alias api, i.e. boost::process::api. Also the 
implementation must use boost.winapi, so windows.h does not get included.