Hi Takashi,
On Dec 10 21:21, Takashi Yano wrote:
> Hi Corinna,
>
> On Mon, 9 Dec 2024 16:26:53 +0100
> Corinna Vinschen wrote:
> > On Dec 9 22:57, Takashi Yano wrote:
> > > On Mon, 9 Dec 2024 22:44:00 +0900
> > > Takashi Yano wrote:
> > > > On Mon, 9 Dec 2024 12:11:56 +0100
> > > > Corinna Vinschen wrote:
> > > > > init_reopen_attr() uses the "open by handle" functionality as in the
> > > > > Win32 API ReOpenFile(). It only does so if the filesystem supports
> > > > > it.
> > > > > Samba usually does, so it's not clear to me why pc.init_reopen_attr()
> > > > > fails for you.
> > > >
> > > > I didn't mean pc.init_reopen_attr() failed. Just I was no idea
> > > > for what handle to be passed.
> > > >
> > > > > > What handle should I pass to pc.init_reopen_attr()?
> > > > >
> > > > > You could pass pc.handle(). Is pc.handle() in this scenario NULL,
> > > > > perhaps?
> > > >
> > > > I have tried pc.handle() and suceeded. Thanks for advice!
> > >
> > > No! pc.handle() sometimes seems to be NULL....
> >
> > Can you please figure out in which scenario it's NULL? Theoretically
> > the function shouldn't even be called in this case.
>
> This seems to happen when check_file_access() is called from av::setup()
> (spawn.cc:1237) called from child_info_spawn::worker() (spawn.cc:358).
Huh, yeah, thanks for tracking this down. And this code snippet is
actually only called if we *failed* opening the file, so there's no
usable handle.
Try this:
>From 23387c343381ba01d02210257e33cf2691611c2d Mon Sep 17 00:00:00 2001
From: Corinna Vinschen <cori...@vinschen.de>
Date: Tue, 10 Dec 2024 13:55:54 +0100
Subject: [PATCH] Cygwin: path_conv: allow NULL handle in init_reopen_attr()
init_reopen_attr() doesn't guard against a NULL handle. However,
there are scenarios calling functions deliberately with a NULL handle,
for instance, av::setup() calling check_file_access() only if opening
the file did NOT succeed.
So check for a NULL handle in init_reopen_attr() and if so, use the
name based approach filling the OBJECT_ATTRIBUTES struct, just as in
the has_buggy_reopen() case.
Fixes: 4c9d01fdad2a ("* mount.h (class fs_info): Add has_buggy_reopen flag and
accessor methods.")
Signed-off-by: Corinna Vinschen <cori...@vinschen.de>
---
winsup/cygwin/local_includes/path.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/winsup/cygwin/local_includes/path.h
b/winsup/cygwin/local_includes/path.h
index 3dd21d975abf..2a05cf44d40a 100644
--- a/winsup/cygwin/local_includes/path.h
+++ b/winsup/cygwin/local_includes/path.h
@@ -323,7 +323,7 @@ class path_conv
}
inline POBJECT_ATTRIBUTES init_reopen_attr (OBJECT_ATTRIBUTES &attr, HANDLE
h)
{
- if (has_buggy_reopen ())
+ if (!h || has_buggy_reopen ())
InitializeObjectAttributes (&attr, get_nt_native_path (),
objcaseinsensitive (), NULL, NULL)
else
--
2.47.0
