From: Johannes Sixt <j6t@kdbg.org>
To: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org,
Johannes Schindelin <johannes.schindelin@gmx.de>,
Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 0/2] Brown-bag fix on top of js/mingw-inherit-only-std-handles
Date: Sat, 30 Nov 2019 20:20:11 +0100 [thread overview]
Message-ID: <7a88a80d-76db-3ca5-c5e1-134b82b5bcbf@kdbg.org> (raw)
In-Reply-To: <pull.480.v2.git.1575110200.gitgitgadget@gmail.com>
Am 30.11.19 um 11:36 schrieb Johannes Schindelin via GitGitGadget:
> Johannes "Hannes" Sixt pointed out that this patch series (which already
> made it to next) introduces a problem: when falling back to spawning the
> process without restricting the file handles, errno is not set accurately.
>
> Sadly, the regression test failure observed by Hannes did not show up over
> here, nor in the PR builds (or, for that matter, the literally hundreds of
> CI builds that patch series underwent as part of Git for Windows' master
> branch). The cause was that errno is set to the expected ENOENT by another
> part of the code, too, that happens right before the calls to
> CreateProcessW(): the test whether a given path refers to a script that
> needs to be executed via an interpreter (such as sh.exe) obviously needs to
> open the file, and that obviously fails, setting errno = ENOENT!
>
> I have currently no idea what function call could be responsible for
> re-setting errno to the reported ERANGE... But at least over here, when I
> partially apply this patch, the part that sets errno = 0;, t0061.2 fails for
> me, too.
>
> Changes since v1:
>
> * A copy/edit fail in the commit message was fixed.
> * We now assign errno only when the call to CreateProcessW() failed.
> * For good measure, we teach the err_win_to_posix() function to translate
> ERROR_SUCCESS into the errno value 0.
This series fixes the observed failure. The changes look good. Thank you
for the quick turn-around.
Tested-by: Johannes Sixt <j6t@kdbg.org>
>
> Johannes Schindelin (2):
> mingw: do set `errno` correctly when trying to restrict handle
> inheritance
> mingw: translate ERROR_SUCCESS to errno = 0
>
> compat/mingw.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>
> base-commit: ac33519ddfa818f420b4ef5a09b4a7b3ac8adeb8
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-480%2Fdscho%2Fmingw-inherit-only-std-handles-set-errno-v2
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-480/dscho/mingw-inherit-only-std-handles-set-errno-v2
> Pull-Request: https://github.com/gitgitgadget/git/pull/480
>
> Range-diff vs v1:
>
> 1: 685360f735 ! 1: 280b6d08a4 mingw: do set `errno` correctly when trying to restrict handle inheritance
> @@ -28,7 +28,10 @@
> test suite, `HOME` points to the test directory), the `errno` has the
> expected value, but for the wrong reasons.
>
> - Let's fix that by making sure that `errno` is set correctly.
> + Let's fix that by making sure that `errno` is set correctly. It even
> + appears that `errno` was set in the _wrong_ case previously:
> + `CreateProcessW()` returns non-zero upon success, but `errno` was set
> + only in the non-zero case.
>
> It would be nice if we could somehow fix t0061 to make sure that this
> does not regress again. One approach that seemed like it should work,
> @@ -37,9 +40,8 @@
>
> However, when `mingw_spawnvpe()` wants to see whether the file in
> question is a script, it calls `parse_interpreter()`, which in turn
> - tries to `open()` the file.0/compat/mingw.c#L1134. Obviously,
> - this call fails, and sets `errno` to `ENOENT`, deep inside the call
> - chain started from that test helper.
> + tries to `open()` the file. Obviously, this call fails, and sets `errno`
> + to `ENOENT`, deep inside the call chain started from that test helper.
>
> Instead, we force re-set `errno` at the beginning of the function
> `mingw_spawnve_fd()`, which _should_ be safe given that callers of that
> @@ -66,9 +68,10 @@
> ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
> TRUE, flags, wenvblk, dir ? wdir : NULL,
> &si.StartupInfo, &pi);
> -+ errno = err_win_to_posix(GetLastError());
> - if (ret && buf.len) {
> -- errno = err_win_to_posix(GetLastError());
> +- if (ret && buf.len) {
> ++ if (!ret)
> + errno = err_win_to_posix(GetLastError());
> ++ if (ret && buf.len) {
> warning("failed to restrict file handles (%ld)\n\n%s",
> err, buf.buf);
> }
> -: ---------- > 2: c3dea00fb1 mingw: translate ERROR_SUCCESS to errno = 0
>
-- Hannes
next prev parent reply other threads:[~2019-11-30 19:20 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-29 21:44 [PATCH 0/1] Brown-bag fix on top of js/mingw-inherit-only-std-handles Johannes Schindelin via GitGitGadget
2019-11-29 21:44 ` [PATCH 1/1] mingw: do set `errno` correctly when trying to restrict handle inheritance Johannes Schindelin via GitGitGadget
2019-11-29 23:02 ` Johannes Sixt
2019-11-30 22:06 ` Johannes Schindelin
2019-11-30 22:16 ` Johannes Sixt
2019-11-30 10:36 ` [PATCH v2 0/2] Brown-bag fix on top of js/mingw-inherit-only-std-handles Johannes Schindelin via GitGitGadget
2019-11-30 10:36 ` [PATCH v2 1/2] mingw: do set `errno` correctly when trying to restrict handle inheritance Johannes Schindelin via GitGitGadget
2019-11-30 10:36 ` [PATCH v2 2/2] mingw: translate ERROR_SUCCESS to errno = 0 Johannes Schindelin via GitGitGadget
2019-11-30 18:04 ` [PATCH v2 0/2] Brown-bag fix on top of js/mingw-inherit-only-std-handles Junio C Hamano
2019-11-30 19:13 ` Johannes Sixt
2019-11-30 20:11 ` Andreas Schwab
2019-11-30 20:23 ` Junio C Hamano
2019-11-30 20:43 ` Andreas Schwab
2019-11-30 21:22 ` Johannes Schindelin
2019-11-30 20:21 ` Junio C Hamano
2019-12-01 6:26 ` Junio C Hamano
2019-12-01 9:53 ` Johannes Schindelin
2019-12-02 6:07 ` Junio C Hamano
2019-12-02 9:05 ` Johannes Schindelin
2019-11-30 19:20 ` Johannes Sixt [this message]
2019-11-30 22:09 ` Junio C Hamano
2019-12-02 11:33 ` [PATCH v3 " Johannes Schindelin via GitGitGadget
2019-12-02 11:33 ` [PATCH v3 1/2] mingw: do set `errno` correctly when trying to restrict handle inheritance Johannes Schindelin via GitGitGadget
2019-12-02 11:33 ` [PATCH v3 2/2] mingw: translate ERROR_SUCCESS to errno = 0 Johannes Schindelin via GitGitGadget
2019-12-02 17:35 ` [PATCH v3 0/2] Brown-bag fix on top of js/mingw-inherit-only-std-handles Johannes Sixt
2019-12-02 19:04 ` Junio C Hamano
2019-12-03 12:04 ` Johannes Schindelin
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