Handling of links with portable dumper

Handling of links with portable dumper

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

A month ago I built master but my use of a symlink in ~/bin
made it not load.

Has that problem been fixed?

-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

Re: Handling of links with portable dumper

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Date: Thu, 04 Apr 2019 18:39:26 -0400
> 
> A month ago I built master but my use of a symlink in ~/bin
> made it not load.
> 
> Has that problem been fixed?

No, not yet.

Re: Handling of links with portable dumper

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

Would you please fix that problem soon?

-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

Re: Handling of links with portable dumper

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: emacs-devel@gnu.org
> Date: Fri, 05 Apr 2019 18:32:11 -0400
> 
> Would you please fix that problem soon?

I cannot test it well enough, and I don't think I understand well
enough the problem and its intended solutions, so I didn't try.
Perhaps Paul or Daniel (CC'ed) or someone else could do that.

Re: Handling of links with portable dumper

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > I cannot test it well enough, and I don't think I understand well
  > enough the problem and its intended solutions, so I didn't try.

Put ~/bin in your path.  Make a symlink from ~/bin/emcs to the executable
of Emacs that you built from master.

Then run emcs and you'll see that it does not find the dump file.  By
stepping through the code that searches for the dump file, you can see
where it goes wrong.

-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

Re: Handling of links with portable dumper

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: eggert@cs.ucla.edu, dancol@dancol.org, emacs-devel@gnu.org
> Date: Sat, 06 Apr 2019 19:24:15 -0400
> 
>   > I cannot test it well enough, and I don't think I understand well
>   > enough the problem and its intended solutions, so I didn't try.
> 
> Put ~/bin in your path.  Make a symlink from ~/bin/emcs to the executable
> of Emacs that you built from master.

That's not the part I didn't understand well enough.  There are other
complications that were discussed at the time, I don't even remember
the details anymore.

Sorry, someone else will have to work on this.

Re: Handling of links with portable dumper

[Daniel Colascione]

>> From: Richard Stallman <rms@gnu.org>
>> Cc: eggert@cs.ucla.edu, dancol@dancol.org, emacs-devel@gnu.org
>> Date: Sat, 06 Apr 2019 19:24:15 -0400
>>
>>   > I cannot test it well enough, and I don't think I understand well
>>   > enough the problem and its intended solutions, so I didn't try.
>>
>> Put ~/bin in your path.  Make a symlink from ~/bin/emcs to the
>> executable
>> of Emacs that you built from master.
>
> That's not the part I didn't understand well enough.  There are other
> complications that were discussed at the time, I don't even remember
> the details anymore.
>
> Sorry, someone else will have to work on this.

I broke it, so I'll buy it. I'll fix this. Paul, is there something in
gnulib I can just link to?

Re: Handling of links with portable dumper

[Paul Eggert]

Daniel Colascione wrote:
> Paul, is there something in
> gnulib I can just link to?

Sorry, I've lost context. What function do you want? canonicalize_file_name? 
set_program_name_and_installdir? I'm not a big fan of the latter, as it's a 
portability heavyweight (it makes lots of assumptions and might not be 
applicable to Emacs).

I still think it'd be better to put the dump into the executable itself, which 
can be done portably simply by linking a big C character array into the 
executable. in the long run this will be better for users (and for us) than 
fiddling with portability minefields like set_program_name_and_installdir.

Re: Handling of links with portable dumper

[Clément Pit-Claudel]

On 2019-04-07 13:44, Paul Eggert wrote:
> I still think it'd be better to put the dump into the executable
> itself, which can be done portably simply by linking a big C
> character array into the executable. in the long run this will be
> better for users (and for us) than fiddling with portability
> minefields like set_program_name_and_installdir.

Does that mean also rewriting the full binary when we rewrite the dump?

Re: Handling of links with portable dumper

[Michael Welsh Duggan]

Clément Pit-Claudel <cpitclaudel@gmail.com> writes:

> On 2019-04-07 13:44, Paul Eggert wrote:
>> I still think it'd be better to put the dump into the executable
>> itself, which can be done portably simply by linking a big C
>> character array into the executable. in the long run this will be
>> better for users (and for us) than fiddling with portability
>> minefields like set_program_name_and_installdir.
>
> Does that mean also rewriting the full binary when we rewrite the dump?

I would assume that when the executable was built it would be dumped
with the dump file created at that time, but that that emacs could load
a different dump file than the one built into it.  I don't see a good
portable way to re-make the executable after the fact absent going back
to the source build, though.

-- 
Michael Welsh Duggan
(md5i@md5i.com)

Re: Handling of links with portable dumper

[Paul Eggert]

Michael Welsh Duggan wrote:
>> Does that mean also rewriting the full binary when we rewrite the dump?
> I would assume that when the executable was built it would be dumped
> with the dump file created at that time, but that that emacs could load
> a different dump file than the one built into it

Yes, the idea is to augment the current approach, not replace it. You'd still be 
able to use the current approach if you wanted to. The default installation 
would be to have a single file rather than two, that's all.

Re: Handling of links with portable dumper

[Eli Zaretskii]

> Date: Sun, 7 Apr 2019 10:04:05 -0700
> From: "Daniel Colascione" <dancol@dancol.org>
> Cc: eggert@cs.ucla.edu, dancol@dancol.org, rms@gnu.org, emacs-devel@gnu.org
> 
> I broke it, so I'll buy it. I'll fix this.

Thanks.

Re: Handling of links with portable dumper

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > >> Put ~/bin in your path.  Make a symlink from ~/bin/emcs to the
  > >> executable
  > >> of Emacs that you built from master.

  > I broke it, so I'll buy it. I'll fix this. Paul, is there something in
  > gnulib I can just link to?

I don't know about gnulib, but if you look at the code that sets
up Vinstallation_directory, also in emacs.c, you can see how it
calls readlink.  It should work to copy and adapt that code.

-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

Re: Handling of links with portable dumper

[Stefan Monnier]

> Would you please fix that problem soon?

FWIW I circumvented it by replacing the symlink with a script.


        Stefan

Re: Handling of links with portable dumper

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > Would you please fix that problem soon?

  > FWIW I circumvented it by replacing the symlink with a script.

Many bugs can be worked around, but this regression ought
to be fixed.


-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)