Unable to execute Cygwin application within UDF format

Unable to execute Cygwin application within UDF format

[Sam Lin]

Hi ,

I will see the problem on WIN10 or WIN SERVER, the duplicate steps are as
follows:

1. Write a simple code 'hello world'  program  and   compiled the
executable file using GCC.

//  hello.c
#include <stdio.h>

int main() {
    printf("Hello World\n");
    return 0;
}

$ gcc hello.c -o hello.exe

2. Format the specified USB drive using command prompt.
  C:\> format <USB Drive Letter>: /fs:UDF /q

3. Put the executable files hello.exe and cygwin1.dll into the UDF format
flash drive and execute.
We will find that the execution error occurs with cygwin v3.2.x and above.

F:\>hello.exe
      0 [main] hello (16224) F:\hello.exe: *** fatal error - add_item
("\??", "/", ...) failed, errno 22
Stack trace:
Frame        Function    Args
000FFFFCCE0  001800622EE (0018029F172, 0018027AE81, 00800000000,
000FFFF8B40)
000FFFFCCE0  0018004874A (00000000000, 000FFFFCCE0, 00180020010,
000FFFFABD6)
000FFFFCCE0  00180048782 (000FFFF9BD0, 00000000016, 00800000000,
00000000001)
000FFFFCCE0  001800E30BC (000FFFFCBD0, 000FFFFCDF0, 001800D7488,
00000000000)
000FFFFCCE0  00180133DC5 (001800D344A, 00000000000, 00000000000,
00000000000)
000FFFFCCE0  00180048DA5 (00000000000, 00000000000, 00000000000,
00000000000)
000FFFFFFF0  00180047856 (00000000000, 00000000000, 00000000000,
00000000000)
000FFFFFFF0  00180047904 (00000000000, 00000000000, 00000000000,
00000000000)
End of stack trace

This error does not occur in v3.1.7.
Hope this will be resolved in the future.

Thanks,
Sam

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

On Fri, 27 May 2022 11:36:27 +0800
Sam Lin wrote:
> I will see the problem on WIN10 or WIN SERVER, the duplicate steps are as
> follows:
> 
> 1. Write a simple code 'hello world'  program  and   compiled the
> executable file using GCC.
> 
> //  hello.c
> #include <stdio.h>
> 
> int main() {
>     printf("Hello World\n");
>     return 0;
> }
> 
> $ gcc hello.c -o hello.exe
> 
> 2. Format the specified USB drive using command prompt.
>   C:\> format <USB Drive Letter>: /fs:UDF /q
> 
> 3. Put the executable files hello.exe and cygwin1.dll into the UDF format
> flash drive and execute.
> We will find that the execution error occurs with cygwin v3.2.x and above.
> 
> F:\>hello.exe
>       0 [main] hello (16224) F:\hello.exe: *** fatal error - add_item
> ("\??", "/", ...) failed, errno 22
> Stack trace:
> Frame        Function    Args
> 000FFFFCCE0  001800622EE (0018029F172, 0018027AE81, 00800000000,
> 000FFFF8B40)
> 000FFFFCCE0  0018004874A (00000000000, 000FFFFCCE0, 00180020010,
> 000FFFFABD6)
> 000FFFFCCE0  00180048782 (000FFFF9BD0, 00000000016, 00800000000,
> 00000000001)
> 000FFFFCCE0  001800E30BC (000FFFFCBD0, 000FFFFCDF0, 001800D7488,
> 00000000000)
> 000FFFFCCE0  00180133DC5 (001800D344A, 00000000000, 00000000000,
> 00000000000)
> 000FFFFCCE0  00180048DA5 (00000000000, 00000000000, 00000000000,
> 00000000000)
> 000FFFFFFF0  00180047856 (00000000000, 00000000000, 00000000000,
> 00000000000)
> 000FFFFFFF0  00180047904 (00000000000, 00000000000, 00000000000,
> 00000000000)
> End of stack trace
> 
> This error does not occur in v3.1.7.
> Hope this will be resolved in the future.

This seems to happen if cygwin1.dll is placed in the root
directly regardless of file system type.

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

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

On Fri, 27 May 2022 13:31:20 +0900
Takashi Yano wrote:
> On Fri, 27 May 2022 11:36:27 +0800
> Sam Lin wrote:
> > I will see the problem on WIN10 or WIN SERVER, the duplicate steps are as
> > follows:
> > 
> > 1. Write a simple code 'hello world'  program  and   compiled the
> > executable file using GCC.
> > 
> > //  hello.c
> > #include <stdio.h>
> > 
> > int main() {
> >     printf("Hello World\n");
> >     return 0;
> > }
> > 
> > $ gcc hello.c -o hello.exe
> > 
> > 2. Format the specified USB drive using command prompt.
> >   C:\> format <USB Drive Letter>: /fs:UDF /q
> > 
> > 3. Put the executable files hello.exe and cygwin1.dll into the UDF format
> > flash drive and execute.
> > We will find that the execution error occurs with cygwin v3.2.x and above.
> > 
> > F:\>hello.exe
> >       0 [main] hello (16224) F:\hello.exe: *** fatal error - add_item
> > ("\??", "/", ...) failed, errno 22
> > Stack trace:
> > Frame        Function    Args
> > 000FFFFCCE0  001800622EE (0018029F172, 0018027AE81, 00800000000,
> > 000FFFF8B40)
> > 000FFFFCCE0  0018004874A (00000000000, 000FFFFCCE0, 00180020010,
> > 000FFFFABD6)
> > 000FFFFCCE0  00180048782 (000FFFF9BD0, 00000000016, 00800000000,
> > 00000000001)
> > 000FFFFCCE0  001800E30BC (000FFFFCBD0, 000FFFFCDF0, 001800D7488,
> > 00000000000)
> > 000FFFFCCE0  00180133DC5 (001800D344A, 00000000000, 00000000000,
> > 00000000000)
> > 000FFFFCCE0  00180048DA5 (00000000000, 00000000000, 00000000000,
> > 00000000000)
> > 000FFFFFFF0  00180047856 (00000000000, 00000000000, 00000000000,
> > 00000000000)
> > 000FFFFFFF0  00180047904 (00000000000, 00000000000, 00000000000,
> > 00000000000)
> > End of stack trace
> > 
> > This error does not occur in v3.1.7.
> > Hope this will be resolved in the future.
> 
> This seems to happen if cygwin1.dll is placed in the root
> directly regardless of file system type.

I meant "root directory".

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

Re: Unable to execute Cygwin application within UDF format

[Sam Lin]

Hi ,

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?
Thanks,
Sam

Takashi Yano <takashi.yano@nifty.ne.jp> 於 2022年5月27日 週五 下午12:32寫道：

> On Fri, 27 May 2022 11:36:27 +0800
> Sam Lin wrote:
> > I will see the problem on WIN10 or WIN SERVER, the duplicate steps are as
> > follows:
> >
> > 1. Write a simple code 'hello world'  program  and   compiled the
> > executable file using GCC.
> >
> > //  hello.c
> > #include <stdio.h>
> >
> > int main() {
> >     printf("Hello World\n");
> >     return 0;
> > }
> >
> > $ gcc hello.c -o hello.exe
> >
> > 2. Format the specified USB drive using command prompt.
> >   C:\> format <USB Drive Letter>: /fs:UDF /q
> >
> > 3. Put the executable files hello.exe and cygwin1.dll into the UDF format
> > flash drive and execute.
> > We will find that the execution error occurs with cygwin v3.2.x and
> above.
> >
> > F:\>hello.exe
> >       0 [main] hello (16224) F:\hello.exe: *** fatal error - add_item
> > ("\??", "/", ...) failed, errno 22
> > Stack trace:
> > Frame        Function    Args
> > 000FFFFCCE0  001800622EE (0018029F172, 0018027AE81, 00800000000,
> > 000FFFF8B40)
> > 000FFFFCCE0  0018004874A (00000000000, 000FFFFCCE0, 00180020010,
> > 000FFFFABD6)
> > 000FFFFCCE0  00180048782 (000FFFF9BD0, 00000000016, 00800000000,
> > 00000000001)
> > 000FFFFCCE0  001800E30BC (000FFFFCBD0, 000FFFFCDF0, 001800D7488,
> > 00000000000)
> > 000FFFFCCE0  00180133DC5 (001800D344A, 00000000000, 00000000000,
> > 00000000000)
> > 000FFFFCCE0  00180048DA5 (00000000000, 00000000000, 00000000000,
> > 00000000000)
> > 000FFFFFFF0  00180047856 (00000000000, 00000000000, 00000000000,
> > 00000000000)
> > 000FFFFFFF0  00180047904 (00000000000, 00000000000, 00000000000,
> > 00000000000)
> > End of stack trace
> >
> > This error does not occur in v3.1.7.
> > Hope this will be resolved in the future.
>
> This seems to happen if cygwin1.dll is placed in the root
> directly regardless of file system type.
>
> --
> Takashi Yano <takashi.yano@nifty.ne.jp>
>
> --
> Problem reports:      https://cygwin.com/problems.html
> FAQ:                  https://cygwin.com/faq/
> Documentation:        https://cygwin.com/docs.html
> Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple
>

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

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.

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

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

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 <corinna@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 <corinna@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.yano@nifty.ne.jp>

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

On Fri, 27 May 2022 19:51:23 +0900
Takashi Yano wrote:
> 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,

I think the following patch makes more sense.

diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
index 01b49468e..5623c9f5f 100644
--- a/winsup/cygwin/cygheap.cc
+++ b/winsup/cygwin/cygheap.cc
@@ -183,6 +183,11 @@ init_cygheap::init_installation_root ()
 	  if (p)
 	    p = wcschr (p + 1, L'\\');  /* Skip share name */
 	}
+      else if (!wcsncmp (p + 2, L"?\\", 2))
+	{
+	  len = 4;
+	  p = installation_root_buf + 4;
+	}
     }
   installation_root_buf[1] = L'?';
   RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,

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

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

On Fri, 27 May 2022 21:28:13 +0900
Takashi Yano wrote:
> On Fri, 27 May 2022 19:51:23 +0900
> Takashi Yano wrote:
> > 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,
> 
> I think the following patch makes more sense.
> 
> diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
> index 01b49468e..5623c9f5f 100644
> --- a/winsup/cygwin/cygheap.cc
> +++ b/winsup/cygwin/cygheap.cc
> @@ -183,6 +183,11 @@ init_cygheap::init_installation_root ()
>  	  if (p)
>  	    p = wcschr (p + 1, L'\\');  /* Skip share name */
>  	}
> +      else if (!wcsncmp (p + 2, L"?\\", 2))
> +	{
> +	  len = 4;
> +	  p = installation_root_buf + 4;
> +	}
>      }
>    installation_root_buf[1] = L'?';
>    RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,

Ah, wcsncmp() check is redundant here. So it is better:

diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
index 01b49468e..34c9e2bc7 100644
--- a/winsup/cygwin/cygheap.cc
+++ b/winsup/cygwin/cygheap.cc
@@ -183,6 +183,11 @@ init_cygheap::init_installation_root ()
 	  if (p)
 	    p = wcschr (p + 1, L'\\');  /* Skip share name */
 	}
+      else
+	{
+	  len = 4;
+	  p = installation_root_buf + 4;
+	}
     }
   installation_root_buf[1] = L'?';
   RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,


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

Re: Unable to execute Cygwin application within UDF format

[Sam Edge]

On 27/05/2022 10:18, 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.

Perhaps the Cygwin DLL is trying to identify the Cygwin root directory
as one higher than its own location so that it can locate /etc/fstab
etc. If it's in the root of a drive maybe it's getting confused. Create
an x:\bin\ directory (where x is the drive letter of the UDF device)
into which to place cygwin1.dll and the executable.

--
Sam Edge

Re: Unable to execute Cygwin application within UDF format

[Ken Brown]

On 5/27/2022 8:36 AM, Takashi Yano wrote:
> diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
> index 01b49468e..34c9e2bc7 100644
> --- a/winsup/cygwin/cygheap.cc
> +++ b/winsup/cygwin/cygheap.cc
> @@ -183,6 +183,11 @@ init_cygheap::init_installation_root ()
>   	  if (p)
>   	    p = wcschr (p + 1, L'\\');  /* Skip share name */
>   	}
> +      else
> +	{
> +	  len = 4;
> +	  p = installation_root_buf + 4;
> +	}
>       }
>     installation_root_buf[1] = L'?';
>     RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,

This looks right to me.  I would just suggest an explanatory comment, something 
like this:

+      else  /* Long path prefix followed by drive letter path */

Ken

Re: Unable to execute Cygwin application within UDF format

[Takashi Yano]

On Sat, 28 May 2022 09:22:12 -0400
Ken Brown wrote:
> On 5/27/2022 8:36 AM, Takashi Yano wrote:
> > diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
> > index 01b49468e..34c9e2bc7 100644
> > --- a/winsup/cygwin/cygheap.cc
> > +++ b/winsup/cygwin/cygheap.cc
> > @@ -183,6 +183,11 @@ init_cygheap::init_installation_root ()
> >   	  if (p)
> >   	    p = wcschr (p + 1, L'\\');  /* Skip share name */
> >   	}
> > +      else
> > +	{
> > +	  len = 4;
> > +	  p = installation_root_buf + 4;
> > +	}
> >       }
> >     installation_root_buf[1] = L'?';
> >     RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,
> 
> This looks right to me.  I would just suggest an explanatory comment, something 
> like this:
> 
> +      else  /* Long path prefix followed by drive letter path */

Thanks for the advice. I will submit the patch to cygwin-patches
mailing list.

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