bug#49864: 28.0.50; Fails to start after "make install"

[Wilhelm Kirschbaum]

It did not go exactly as the above, but adding the whole log here in case it helps, as I am not 100% sure if I did it correctly; will go over it again later in today.

~/src/tools/emacs/src $ gdb /usr/local/bin/emacs-28.0.50
GNU gdb (GDB) 10.2
Copyright (C) 2021 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /usr/local/bin/emacs-28.0.50...
warning: File "/home/wilhelm/src/tools/emacs/src/.gdbinit" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
To enable execution of this file add
add-auto-load-safe-path /home/wilhelm/src/tools/emacs/src/.gdbinit
line to your configuration file "/home/wilhelm/.gdbinit".
To completely disable this security protection add
set auto-load safe-path /
line to your configuration file "/home/wilhelm/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
info "(gdb)Auto-loading safe path"
(gdb) source ./.gdbinit
SIGINT is used by the debugger.
Are you sure you want to change it? (y or n) [answered Y; input not from terminal]
DISPLAY = :0.0
TERM = xterm-256color
Breakpoint 1 at 0x4766c: file emacs.c, line 399.
Breakpoint 2 at 0x105420: file xterm.c, line 10258.
(gdb) break pdumper.c:5315
Breakpoint 3 at 0x19959d: file pdumper.c, line 5315.
(gdb) r -Q
Starting program: /usr/local/bin/emacs-28.0.50 -Q
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".

Breakpoint 3, dump_do_dump_relocation (dump_base=<optimized out>, reloc=...) at pdumper.c:5315
5315 if (installation_state == UNKNOWN)
(gdb) p cu_file1
$1 = XIL(0x7ffff08e4bac)
(gdb) xstring
$2 = (struct Lisp_String *) 0x7ffff08e4ba8
"../lib/emacs/28.0.50/native-lisp/28.0.50-864bf4e5/preloaded/window-0d1b8b93-dcb2375f.eln"
(gdb) p cu_file2
$3 = XIL(0x7ffff08e4b8c)
(gdb) xstring
$4 = (struct Lisp_String *) 0x7ffff08e4b88
"../native-lisp/28.0.50-864bf4e5/preloaded/window-0d1b8b93-dcb2375f.eln"
(gdb) n
5317    eln_fname = make_uninit_string (execdir_len + fn1_len);
(gdb) n
5318    fndata = SSDATA (eln_fname);
(gdb) n
5319    memcpy (fndata, emacs_execdir, execdir_len);
(gdb) n
1561  return XSTRING (string)->u.s.data;
(gdb) n
5321    if (file_access_p (fndata, F_OK))
(gdb) p fndata
$5 = <optimized out>
(gdb) next
5325 eln_fname = make_uninit_string (execdir_len + fn2_len);
(gdb) p errno
'errno' has unknown type; cast it to its declared type
(gdb) n
5326 fndata = SSDATA (eln_fname);
(gdb) n
5327 memcpy (fndata, emacs_execdir, execdir_len);
(gdb) n
1561  return XSTRING (string)->u.s.data;
(gdb) n
5329 installation_state = LOCAL_BUILD;
(gdb) p fndata
$6 = <optimized out>
(gdb) n
5331    fixup_eln_load_path (eln_fname);
(gdb) n
5352 comp_u->file = eln_fname;
(gdb) p eln_fname
$7 = XIL(0x555555c2bcb4)
(gdb) xstring
$8 = (struct Lisp_String *) 0x555555c2bcb0
"/usr/local/libexec/emacs/28.0.50/x86_64-pc-linux-gnu/../../../../bin/../native-lisp/28.0.50-864bf4e5/preloaded/window-0d1b8b93-dcb2375f.eln"
(gdb) n
1561  return XSTRING (string)->u.s.data;
(gdb) n
5354 if (!comp_u->handle)
(gdb) n
5356    fprintf (stderr, "Error using execdir %s:\n",
(gdb) n
Error using execdir /usr/local/libexec/emacs/28.0.50/x86_64-pc-linux-gnu/../../../../bin/:
5358    error ("%s", dynlib_error ());
(gdb) p errno
'errno' has unknown type; cast it to its declared type
(gdb) n
emacs: /usr/local/libexec/emacs/28.0.50/x86_64-pc-linux-gnu/../../../../bin/../native-lisp/28.0.50-864bf4e5/preloaded/window-0d1b8b93-dcb2375f.eln: cannot open shared object file: No such file or directory
[Inferior 1 (process 4129) exited with code 01]
(gdb) q

On Thu, Aug 5, 2021 at 9:59 AM Eli Zaretskii <eliz@gnu.org> wrote:

> From: Wilhelm Kirschbaum <wkirschbaum@gmail.com>
> Date: Thu, 5 Aug 2021 09:14:10 +0200
> Cc: 49864@debbugs.gnu.org
>
> Yes, of course, but I will only be able to do it a bit later today. I am not too familiar with GDB though.

Thanks.  The instructions are below:

  $ cd /home/wilhelm/src/tools/emacs/src
  $ gdb /usr/local/bin/emacs-28.0.50
  ...
  (gdb) source ./.gdbinit
  (gdb) break pdumper.c:5315
  (gdb) r -Q

When GDB announces that the breakpoint at pdumper.c:5315 breaks, do
this:

  (gdb) p cu_file1
  (gdb) xstring
  (gdb) p cu_file2
  (gdb) xstring

and show the results of these commands.  Then step through the code,
one line at a time, with the "n" ("next") command.  Eventually, you
should get to line 5321:

  5321                if (file_access_p (fndata, F_OK))

Then show the value of fndata, which should be a file name:

  (gdb) p fndata

Type "next" again.  If the file_access_p call fails (returns 'false'),
show the value of errno immediately after stepping past the line that
calls file_access_p:

  (gdb) p errno

In that case (if file_access_p fails), the "next" command will land
you in this block:

            else
              {
                eln_fname = make_uninit_string (execdir_len + fn2_len);
                fndata = SSDATA (eln_fname);
                memcpy (fndata, emacs_execdir, execdir_len);
                memcpy (fndata + execdir_len, SSDATA (cu_file2), fn2_len);
                installation_state = LOCAL_BUILD;
              }

Please type "n" ("next") repeatedly until you get to the last line,
which starts with "installation_state =", and show the value of
fndata:

  (gdb) p fndata

Finally, keep stepping with "n" until you come to this line:

        comp_u->handle = dynlib_open (SSDATA (eln_fname));

and type the following commands:

  (gdb) p eln_fname
  (gdb) xstring

and show their results.

You can then terminate the GDB session:

  (gdb) q

(Answer "y" if it asks whether to quit.)

I hope the data you collect and report will explain what happens, or
at least give us a direction in which to look for the explanation.

Thanks again for your help in this matter.