[PATCH 1/1] cygwin: use CREATE_DEFAULT_ERROR_MODE in spawn

[Jeremy Drake]

On Tue, 8 Dec 2020, Jon Turney wrote:
> On 07/12/2020 09:43, Corinna Vinschen wrote:
> > On Dec  4 10:35, Jeremy Drake via Cygwin-patches wrote:
> > > On Fri, 4 Dec 2020, Corinna Vinschen via Cygwin-patches wrote:
> > >
> > > > I'm not happy about a new CYGWIN option.
> > > >
> > > > Wouldn't it make sense, perhaps, to switch to CREATE_DEFAULT_ERROR_MODE
> > > > for all non-Cygwin processes by default instead?
>
> I agree.
>
> Cygwin calls SetErrorMode(), so we need to use this flag to prevent that
> non-default behaviour being inherited by processes started with
> CreateProcess().
>

In that case, here's my initial, much simpler patch

-- >8 --
Subject: [PATCH] cygwin: use CREATE_DEFAULT_ERROR_MODE in spawn

This allows native processes to get Windows-default error handling
behavior (such as invoking the registered JIT debugger), while cygwin
processes would quickly set their error mode back to what they expect.
---
 winsup/cygwin/spawn.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index c77d62984..f5952d53b 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -429,7 +429,8 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
       c_flags = GetPriorityClass (GetCurrentProcess ());
       sigproc_printf ("priority class %d", c_flags);

-      c_flags |= CREATE_SEPARATE_WOW_VDM | CREATE_UNICODE_ENVIRONMENT;
+      c_flags |= CREATE_SEPARATE_WOW_VDM | CREATE_UNICODE_ENVIRONMENT
+	      | CREATE_DEFAULT_ERROR_MODE;

       /* We're adding the CREATE_BREAKAWAY_FROM_JOB flag here to workaround
 	 issues with the "Program Compatibility Assistant (PCA) Service".