Re: [PATCH v3 0/2] Brown-bag fix on top of js/mingw-inherit-only-std-handles

[Johannes Sixt <j6t@kdbg.org>]

Am 02.12.19 um 12:33 schrieb Johannes Schindelin via GitGitGadget:
> Range-diff vs v2:
> 
>  1:  280b6d08a4 = 1:  280b6d08a4 mingw: do set `errno` correctly when trying to restrict handle inheritance
>  2:  c3dea00fb1 ! 2:  e04e1269b3 mingw: translate ERROR_SUCCESS to errno = 0
>      @@ -3,12 +3,15 @@
>           mingw: translate ERROR_SUCCESS to errno = 0

The subject line would have to be adjusted as well.

	mingw: forbid translating ERROR_SUCCESS to an errno value

or something.

>       
>           Johannes Sixt pointed out that the `err_win_to_posix()` function
>      -    mishandles `ERROR_SUCCESS`. This commit fixes that.
>      +    mishandles `ERROR_SUCCESS`: it maps it to `ENOSYS`.
>       
>      -    Technically, we try to only assign `errno` to the corresponding value of
>      -    `GetLastError()` (which translation is performed by that function) when
>      -    a Win32 API call failed, so this change is purely defensive and is not
>      -    expected to fix an existing bug in our code base.
>      +    The only purpose of this function is to map Win32 API errors to `errno`
>      +    ones, and there is actually no equivalent to `ERROR_SUCCESS`: the idea
>      +    of `errno` is that it will only be set in case of an error, and left
>      +    alone in case of success.
>      +
>      +    Therefore, as pointed out by Junio Hamano, it is a bug to call this
>      +    function when there was not even any error to map.
>       
>           Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
>       
>      @@ -19,7 +22,7 @@
>        	case ERROR_SHARING_BUFFER_EXCEEDED: error = ENFILE; break;
>        	case ERROR_SHARING_VIOLATION: error = EACCES; break;
>        	case ERROR_STACK_OVERFLOW: error = ENOMEM; break;
>      -+	case ERROR_SUCCESS: error = 0; break;
>      ++	case ERROR_SUCCESS: BUG("err_win_to_posix() called without an error!");
>        	case ERROR_SWAPERROR: error = ENOENT; break;
>        	case ERROR_TOO_MANY_MODULES: error = EMFILE; break;
>        	case ERROR_TOO_MANY_OPEN_FILES: error = EMFILE; break;
> 

-- Hannes