[PATCH] Cygwin: pty: Fix 'Bad address' error when running 'cmd.exe /c dir'

[Takashi Yano]

On Sat, 22 Oct 2022 07:58:37 +0200
Johannes Schindelin wrote:
> On October 22, 2022 7:34:20 AM GMT+02:00, Takashi Yano <takashi.yano@nifty.ne.jp> wrote:
> >- If the command executed is 'cmd.exe /c [...]', runpath in spawn.cc
> >  will be NULL. In this case, is_console_app(runpath) check causes
> >  access violation. This case also the command executed is obviously
> >  console app., therefore, treat it as console app to fix this issue.
> >
> >  Addresses: https://github.com/msys2/msys2-runtime/issues/108
> >---
> > winsup/cygwin/spawn.cc | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> >diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
> >index 5aa52ab1e..4fc842a2b 100644
> >--- a/winsup/cygwin/spawn.cc
> >+++ b/winsup/cygwin/spawn.cc
> >@@ -215,6 +215,8 @@ handle (int fd, bool writing)
> > static bool
> > is_console_app (WCHAR *filename)
> > {
> >+  if (filename == NULL)
> >+    return true; /* The command executed is command.com or cmd.exe. */
> >   HANDLE h;
> >   const int id_offset = 92;
> >   h = CreateFileW (filename, GENERIC_READ, FILE_SHARE_READ,
> 
> The commit message of the original patch was substantially clearer and offered a thorough analysis. This patch lost that.

The reason which I did not apply your patch as-is is:
is_console_app() returns false for 'cmd.exe /c [...]' case
with your patch, while it should return true. 

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>