On Fri, 27 May 2022 18:18:49 +0900
Takashi Yano wrote:
> On Fri, 27 May 2022 16:47:09 +0800
> Sam Lin wrote:
> > I have also successfully executed that is to move cygwin1.dll to the root
> > directory to execute.
> >
> > Will cygwin1.dll be supported to execute in UDF format in the future?
>
> As I wrote earlier, it doesn't matter that the file system
> is UDF. cygwin1.dll 3.2.0 and later seems to cause problems
> if it is placed in the root directory.
>
> Even with UDF format, the problem does not occur if hello.exe
> and cygwin1.dll are placed in any directory other than root
> directory.
I looked into this problem and found the problem occurs after
the commit:
commit 6d898f43fc87a7bf3ab100d75538e381bd86f657
Author: Corinna Vinschen <cori...@vinschen.de>
Date: Fri Feb 19 18:15:58 2021 +0100
Cygwin: realpath: fix cygwin installation dir being access via junction
Consider this case:
- Cygwin installed in C:\cygwin64
- mklink /j D:\cygwin64 C:\cygwin64
- create testcase calling
realpath("/", result);
printf ("%s\n", result);
- start cmd
>C:\cygwin64\bin\bash -lc <path-to-testcase>
/
>D\cygwin64\bin\bash -lc <path-to-testcase>
/cygdrive/c/cygwin64
This scenario circumventing the mount point handling which is automated
in terms of /, depending on the path returned from GetModuleFileNameW
for the Cygwin DLL. When calling D:\cygwin64\bin\bash the dir returned
from GetModuleFileNameW is D:\cygwin64\bin, thus root is D:\cygwin64.
However, junctions are treated as symlinks in Cygwin which explains why
the path gets converted to a cygdrive path.
Fix this by calling GetFinalPathNameByHandleW on the result from
GetModuleFileNameW to get the correct root path, even if accessed via
a junction point.
Signed-off-by: Corinna Vinschen <cori...@vinschen.de>
And also found the following patch fixes the issue.
diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
index 01b49468e..c4031b919 100644
--- a/winsup/cygwin/cygheap.cc
+++ b/winsup/cygwin/cygheap.cc
@@ -183,6 +183,8 @@ init_cygheap::init_installation_root ()
if (p)
p = wcschr (p + 1, L'\\'); /* Skip share name */
}
+ else
+ p = installation_root_buf + 4; /* 4 is the length of "\\\\?\\" */
}
installation_root_buf[1] = L'?';
RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,
--
Takashi Yano <takashi.y...@nifty.ne.jp>
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