bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Guy Offer via Bug reports for GNU Emacs, the Swiss army knife of text editors]

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Working on Cygwin Emacs when source code is located on Windows 10
network drives (e.g. Windows F: drive points to \\fileserver\soruce) and accessed
by gdb using \cygdrive\f\source\.. the Emacs gdb support cannot find the
file.
File can only be find by the Emacs GDB support if the source path begins with
double slash (e.g,, \\cygdrive\f\source\...).  However in this case it
cannot be found by the gud gdb window.
To overcome this source mounts should be done directly from the Cygwin (using mount) and not
through the Windows 10 drives (\cygdrive\...).


In GNU Emacs 27.2 (build 1, x86_64-pc-cygwin, X toolkit, Xaw3d scroll bars)
of 2021-03-26 built on moufang2
Repository revision: 5a2c58d08c59ce5a7afb6511cc99f722f426c12b
Repository branch: master
Windowing system distributor 'The Cygwin/X Project', version 11.0.12012000
Recent messages:
(No changes need to be saved)
elisp--preceding-sexp: End of file during parsing
Saving file /cygdrive/c/Temp/cmd3...
Wrote /cygdrive/c/Temp/cmd3
(No changes need to be saved) [3 times]
Undefined command: "exit".  Try "help".
Switched to thread 1
Mark set
Target doesn't support non-stop mode.  Turning it off.
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bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Eli Zaretskii]

> Date: Tue, 16 Nov 2021 09:22:26 +0000
> From:  Guy Offer via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Working on Cygwin Emacs when source code is located on Windows 10
> network drives (e.g. Windows F: drive points to \\fileserver\soruce) and accessed
> by gdb using \cygdrive\f\source\.. the Emacs gdb support cannot find the
> file.
> 
> File can only be find by the Emacs GDB support if the source path begins with
> double slash (e.g,, \\cygdrive\f\source\...).  However in this case it
> cannot be found by the gud gdb window.
> To overcome this source mounts should be done directly from the Cygwin (using mount) and not
> through the Windows 10 drives (\cygdrive\...). 

Please show what does the GDB you are using display when you type
this:

  $ gdb --config

Also, when you say "the Emacs gdb support cannot find the file", what
do you mean by "Emacs gdb support"?

Thanks.

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Guy Offer via Bug reports for GNU Emacs, the Swiss army knife of text editors]

This GDB was configured as follows:
   configure --host=x86_64-pc-cygwin --target=x86_64-redhat-linux-gnu
             --with-auto-load-dir=$debugdir:$datadir/auto-load
             --with-auto-load-safe-path=$debugdir:$datadir/auto-load
             --with-expat
             --with-gdb-datadir=/usr/local/share/gdb (relocatable)
             --with-jit-reader-dir=/usr/local/lib/gdb (relocatable)
             --without-libunwind-ia64
             --without-lzma
             --without-babeltrace
             --without-intel-pt
             --without-mpfr
             --without-xxhash
             --without-python
             --without-python-libdir
             --without-debuginfod
             --without-guile
             --disable-source-highlight
             --with-separate-debug-dir=/usr/local/lib/debug (relocatable)

Regarding Emacs GDB support: Emacs has UI support for GDB (GUD GDB) which can display code source in Emacs buffers. 


("Relocatable" means the directory can be moved with the GDB installation
tree, and GDB will still find it.)
-----Original Message-----
From: Eli Zaretskii [mailto:eliz@gnu.org] 
Sent: Tuesday, 16 November 2021 17:17
To: Guy Offer <guyof@checkpoint.com>
Cc: 51894@debbugs.gnu.org
Subject: Re: bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

> Date: Tue, 16 Nov 2021 09:22:26 +0000
> From:  Guy Offer via "Bug reports for GNU Emacs,  the Swiss army knife 
> of text editors" <bug-gnu-emacs@gnu.org>
> 
> Working on Cygwin Emacs when source code is located on Windows 10 
> network drives (e.g. Windows F: drive points to \\fileserver\soruce) 
> and accessed by gdb using \cygdrive\f\source\.. the Emacs gdb support 
> cannot find the file.
> 
> File can only be find by the Emacs GDB support if the source path 
> begins with double slash (e.g,, \\cygdrive\f\source\...).  However in 
> this case it cannot be found by the gud gdb window.
> To overcome this source mounts should be done directly from the Cygwin 
> (using mount) and not through the Windows 10 drives (\cygdrive\...).

Please show what does the GDB you are using display when you type
this:

  $ gdb --config

Also, when you say "the Emacs gdb support cannot find the file", what do you mean by "Emacs gdb support"?

Thanks.


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bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Eli Zaretskii]

> From: Guy Offer <guyof@checkpoint.com>
> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
> Date: Wed, 17 Nov 2021 14:00:39 +0000
> 
> This GDB was configured as follows:
>    configure --host=x86_64-pc-cygwin --target=x86_64-redhat-linux-gnu

Does this mean this is a GDB that targets Red Hat GNU/Linux and not a
Cygwin-native debugger?

> Regarding Emacs GDB support: Emacs has UI support for GDB (GUD GDB) which can display code source in Emacs buffers. 

Are you using "M-x gdb RET" or "M-x gud-gdb RET"?

Also, is Emacs capable of visiting file specified as
"\cygdrive\f\source\", i.e. does "C-x C-f" work with such names?

And btw, why you mention file names with backslashes? does using
forward slashes, as in "/cygdrive/f/source/", work for you?

If all of the above doesn't help, please show a minimal recipe
starting from "emacs -Q", where the problem happens: maybe we are
missing some important clue.

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Guy Offer via Bug reports for GNU Emacs, the Swiss army knife of text editors]

-----Original Message-----
From: Eli Zaretskii [mailto:eliz@gnu.org] 
Sent: Wednesday, 17 November 2021 16:28
To: Guy Offer <guyof@checkpoint.com>
Cc: 51894@debbugs.gnu.org
Subject: Re: bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

> From: Guy Offer <guyof@checkpoint.com>
> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
> Date: Wed, 17 Nov 2021 14:00:39 +0000
> 
> This GDB was configured as follows:
>    configure --host=x86_64-pc-cygwin --target=x86_64-redhat-linux-gnu

Does this mean this is a GDB that targets Red Hat GNU/Linux and not a Cygwin-native debugger? yes

> Regarding Emacs GDB support: Emacs has UI support for GDB (GUD GDB) which can display code source in Emacs buffers. 

Are you using "M-x gdb RET" or "M-x gud-gdb RET"? M-x gdb RET

Also, is Emacs capable of visiting file specified as "\cygdrive\f\source\", i.e. does "C-x C-f" work with such names? Emacs can do that if I load the file manually.  However, when emacs tries to open the file as received from gdb (to display the source) it fails.  It only succeeds if I set the pathname to \\cygdrive\f\source.  However in that case the gdb command window cannot access the file. 
Pls note that this happens only if f is a network drive .



And btw, why you mention file names with backslashes? does using forward slashes, as in "/cygdrive/f/source/", work for you?
Sorry for the confusion in the bug report - I used only slashes .  
/cygdrive/f/source - worked for accessing source from the gdb command window (GUD gdb window) but not for opening the source from the GDB buffer.
//cygdrive/f/source - worked for opening the source in a GDB buffer but not for accessing the source from the gdb command window. 
This happened when f points to a remote network drive. 

If all of the above doesn't help, please show a minimal recipe starting from "emacs -Q", where the problem happens: maybe we are missing some important clue.


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bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Eli Zaretskii]

> From: Guy Offer <guyof@checkpoint.com>
> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
> Date: Wed, 17 Nov 2021 15:01:09 +0000
> 
> Also, is Emacs capable of visiting file specified as "\cygdrive\f\source\", i.e. does "C-x C-f" work with such names? Emacs can do that if I load the file manually.  However, when emacs tries to open the file as received from gdb (to display the source) it fails.  It only succeeds if I set the pathname to \\cygdrive\f\source.  However in that case the gdb command window cannot access the file. 

Please show the Emacs commands and GDB commands you use in these two
cases.  I'm not sure I understand what you mean by "load file
manually" and "open a file received from gdb"

> Pls note that this happens only if f is a network drive .

So maybe it's a Cygwin-specific problem with networked drives?  I'll
CC Ken Brown, who is our Cygwin specialist.  Ken, does this ring a
bell? does /cygdrive/x/ fail when X is a networked drive?

Or maybe the way your networked drives are mounted prevents Emacs from
accessing them due to some authentication issue?

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Ken Brown]

On 11/17/2021 12:03 PM, Eli Zaretskii wrote:
>> From: Guy Offer <guyof@checkpoint.com>
>> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
>> Date: Wed, 17 Nov 2021 15:01:09 +0000
>> Pls note that this happens only if f is a network drive .
> 
> So maybe it's a Cygwin-specific problem with networked drives?  I'll
> CC Ken Brown, who is our Cygwin specialist.  Ken, does this ring a
> bell? does /cygdrive/x/ fail when X is a networked drive?

I'm not aware of any such problem.  I never use networked drives myself, but if 
Guy can tell me exactly how he created his, I'll see if I can reproduce the problem.

Ken

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Guy Offer via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Hi, 

Steps to set up this configuration:

Background: 
When working on gdb from Emacs you can see the source code from 2 Emacs windows/buffers:
- the gdb command window: the gdb prompt that displays the current source code line.
- the primary source window: an Emacs window that automatically opened and displays the source file with an arrow pointing on the current line being processed.
The problem is that when the source code is on network drive mounted through Windows 10 drives (F:, G:, etc.) it will not be available to one of these windows. 

Working machine : Windows 10

* Have the source pointed by a network drive (e.g. F:/source, etc.).
* Install Cygwin on the local machine: (including make, X11, GNU Emacs 27.2, gcc, packages etc.). 
* Download and compile gdb 11.1 (I had to compile myself to work with linux target and build x86_64-redhat-linux-gnu-gdb).
* Activate gdb from emacs by : Alt-x, gdb, gdb -i=mi etc.

Now you see the problems:
* If you set the code path (set substitute-path) to the actual code location /cygdrive/f/source the code will be available to the gdb command window but will not be opened automatically in the primary source window/buffer. 
* If you set the code location to //cygdrive/f/source the code will be available to the source window - but not to the gdb command window. 

Possible solution - mounting the source code through Cygwin /mnt. 

Another problem : when the source is not available the Emacs command prompt get into a loop.

Thanks,
Guy


-----Original Message-----
From: Ken Brown [mailto:kbrown@cornell.edu] 
Sent: Wednesday, 17 November 2021 19:41
To: Eli Zaretskii <eliz@gnu.org>; Guy Offer <guyof@checkpoint.com>
Cc: 51894@debbugs.gnu.org
Subject: Re: bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

On 11/17/2021 12:03 PM, Eli Zaretskii wrote:
>> From: Guy Offer <guyof@checkpoint.com>
>> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
>> Date: Wed, 17 Nov 2021 15:01:09 +0000 Pls note that this happens only 
>> if f is a network drive .
> 
> So maybe it's a Cygwin-specific problem with networked drives?  I'll 
> CC Ken Brown, who is our Cygwin specialist.  Ken, does this ring a 
> bell? does /cygdrive/x/ fail when X is a networked drive?

I'm not aware of any such problem.  I never use networked drives myself, but if Guy can tell me exactly how he created his, I'll see if I can reproduce the problem.

Ken


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bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Eli Zaretskii]

> From: Guy Offer <guyof@checkpoint.com>
> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
> Date: Thu, 18 Nov 2021 07:53:37 +0000
> 
> * If you set the code path (set substitute-path) to the actual code location /cygdrive/f/source the code will be available to the gdb command window but will not be opened automatically in the primary source window/buffer. 
> * If you set the code location to //cygdrive/f/source the code will be available to the source window - but not to the gdb command window. 

Why is "set substitute-path" command needed?  The program you are
debugging should have the source location recorded in the debug info,
so that step should not be needed.

I'm asking because perhaps this step is an important part of the
problem.

Also, can you try "M-x gud-gdb RET" instead, and see if the problem
exists there as well?  Maybe there's something in gdb-mi.el that
doesn't work well in this case, in particular when it parses the file
names reported by GDB's MI interface.  For that reason, I'd be
interested to see the raw data about source file names emitted by GDB
in response to Emacs's queries.  For that purpose, activate the
gdb-enable-debug minor mode, and show the contents of the variable
gdb-debug-log after a command that results in such failures.

> Another problem : when the source is not available the Emacs command prompt get into a loop.

I believe that was fixed in Emacs 28.

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Guy Offer via Bug reports for GNU Emacs, the Swiss army knife of text editors]

-----Original Message-----
From: Eli Zaretskii [mailto:eliz@gnu.org] 
Sent: Thursday, 18 November 2021 10:41
To: Guy Offer <guyof@checkpoint.com>
Cc: kbrown@cornell.edu; 51894@debbugs.gnu.org
Subject: Re: bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

> From: Guy Offer <guyof@checkpoint.com>
> CC: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
> Date: Thu, 18 Nov 2021 07:53:37 +0000
> 
> * If you set the code path (set substitute-path) to the actual code location /cygdrive/f/source the code will be available to the gdb command window but will not be opened automatically in the primary source window/buffer. 
> * If you set the code location to //cygdrive/f/source the code will be available to the source window - but not to the gdb command window. 

Why is "set substitute-path" command needed?  The program you are debugging should have the source location recorded in the debug info, so that step should not be needed.


I'm asking because perhaps this step is an important part of the problem.
===>
	It was compiled on a different location. 
	I had the same problem occurring when using the "directory" command (adding a directory to the source search path) as well.


Also, can you try "M-x gud-gdb RET" instead, and see if the problem exists there as well?  Maybe there's something in gdb-mi.el that doesn't work well in this case, in particular when it parses the file names reported by GDB's MI interface.  For that reason, I'd be interested to see the raw data about source file names emitted by GDB in response to Emacs's queries.  For that purpose, activate the gdb-enable-debug minor mode, and show the contents of the variable gdb-debug-log after a command that results in such failures.

=====> The gud-gdb does not have the IDE support (it only runs the gdb on a single window without opening the source files, stack or variable windows).

> Another problem : when the source is not available the Emacs command prompt get into a loop.

I believe that was fixed in Emacs 28.


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bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Eli Zaretskii]

> From: Guy Offer <guyof@checkpoint.com>
> CC: "kbrown@cornell.edu" <kbrown@cornell.edu>,
>         "51894@debbugs.gnu.org"
> 	<51894@debbugs.gnu.org>
> Date: Thu, 18 Nov 2021 08:54:22 +0000
> 
> Also, can you try "M-x gud-gdb RET" instead, and see if the problem exists there as well?  Maybe there's something in gdb-mi.el that doesn't work well in this case, in particular when it parses the file names reported by GDB's MI interface.  For that reason, I'd be interested to see the raw data about source file names emitted by GDB in response to Emacs's queries.  For that purpose, activate the gdb-enable-debug minor mode, and show the contents of the variable gdb-debug-log after a command that results in such failures.
> 
> =====> The gud-gdb does not have the IDE support (it only runs the gdb on a single window without opening the source files, stack or variable windows).

That's not entirely true: it does open a window with the source file.

Anyway I'm not saying you should use "M-x gud-gdb" instead of "M-x
gdb", I'm asking you to try gud-gdb just this once to see if it is
capable of resolving these file names.  Could you please try that and
report the results?  Knowing that could give some hint about where to
look for the reasons of your original problem.

Thanks.

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Ken Brown]

On 11/18/2021 2:53 AM, Guy Offer wrote:
> * Have the source pointed by a network drive (e.g. F:/source, etc.).
> * Install Cygwin on the local machine: (including make, X11, GNU Emacs 27.2, gcc, packages etc.).
> * Download and compile gdb 11.1 (I had to compile myself to work with linux target and build x86_64-redhat-linux-gnu-gdb).
> * Activate gdb from emacs by : Alt-x, gdb, gdb -i=mi etc.

I don't have time to try to replicate this setup, nor do I have a Linux machine 
on my network.  But I did map a network drive and verify that there was no 
problem accessing it via the cygdrive prefix (e.g., 'ls /cygdrive/x' succeeds 
after X: is mapped to a folder that I can access on a networked Windows 
machine).  This answers a question that Eli asked earlier.

Ken

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Eli Zaretskii]

> Date: Thu, 18 Nov 2021 09:17:58 -0500
> Cc: "51894@debbugs.gnu.org" <51894@debbugs.gnu.org>
> From: Ken Brown <kbrown@cornell.edu>
> 
> I don't have time to try to replicate this setup, nor do I have a Linux machine 
> on my network.  But I did map a network drive and verify that there was no 
> problem accessing it via the cygdrive prefix (e.g., 'ls /cygdrive/x' succeeds 
> after X: is mapped to a folder that I can access on a networked Windows 
> machine).  This answers a question that Eli asked earlier.

Thanks.  So some other factor must be at work here.  I think the
solution of the riddle is somewhere in what GDB/MI returns to Emacs in
response to its requests, which is why I asked for gdb-debug-log
contents.

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Ken Brown]

On 11/18/2021 9:58 AM, Eli Zaretskii wrote:
> Thanks.  So some other factor must be at work here.  I think the
> solution of the riddle is somewhere in what GDB/MI returns to Emacs in
> response to its requests, which is why I asked for gdb-debug-log
> contents.

One other thing that could be relevant is that Guy is using a self-built gdb 
11.1, based presumably on the upstream sources.  Cygwin's gdb is at version 
10.2, and the maintainer has applied 9 patches to the upstream sources.

Guy, maybe you should try imitating the build of Cygwin's gdb-10.2 package.

Ken

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Lars Ingebrigtsen]

Ken Brown <kbrown@cornell.edu> writes:

>> Thanks.  So some other factor must be at work here.  I think the
>> solution of the riddle is somewhere in what GDB/MI returns to Emacs in
>> response to its requests, which is why I asked for gdb-debug-log
>> contents.
>
> One other thing that could be relevant is that Guy is using a
> self-built gdb 11.1, based presumably on the upstream sources.
> Cygwin's gdb is at version 10.2, and the maintainer has applied 9
> patches to the upstream sources.
>
> Guy, maybe you should try imitating the build of Cygwin's gdb-10.2 package.

Skimming this thread, I'm not sure there's anything actionable here --
the problems seem like they might be stemming from a self-built version
of gdb, which seems outside of the scope of the Emacs bug tracker.

So is there anything to do here on our side, or should this bug report
be closed?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#51894: 27.2; GDB Gud support on Cygwin has trouble accessing shared files on Windows network drives.

[Ken Brown]

On 12/23/2021 5:22 AM, Lars Ingebrigtsen wrote:
> Ken Brown <kbrown@cornell.edu> writes:
> 
>>> Thanks.  So some other factor must be at work here.  I think the
>>> solution of the riddle is somewhere in what GDB/MI returns to Emacs in
>>> response to its requests, which is why I asked for gdb-debug-log
>>> contents.
>>
>> One other thing that could be relevant is that Guy is using a
>> self-built gdb 11.1, based presumably on the upstream sources.
>> Cygwin's gdb is at version 10.2, and the maintainer has applied 9
>> patches to the upstream sources.
>>
>> Guy, maybe you should try imitating the build of Cygwin's gdb-10.2 package.
> 
> Skimming this thread, I'm not sure there's anything actionable here --
> the problems seem like they might be stemming from a self-built version
> of gdb, which seems outside of the scope of the Emacs bug tracker.
> 
> So is there anything to do here on our side, or should this bug report
> be closed?

I think it should be closed (and I'm doing so).

Ken