[v3] Make only user-specified executable and symbol filenames sticky

  Philippe Waroquiers wrote:
> On Fri, 2015-06-05 at 12:22 +0100, Gary Benson wrote:
> > Built and regtested on RHEL6.6 x86_64.
> I tested with the last SVN version of the Valgrind gdbserver (that
> supports qXfer:exec-file:read+).
> 
> The patch introduces a regression:
> with the patch, GDB does not anymore automatically load the
> exec-file.
> 
> I bypassed this problem by ignoring fake_pid_p in remote.c:
> --- a/gdb/remote.c
> +++ b/gdb/remote.c
> @@ -1624,9 +1624,13 @@ remote_add_inferior (int fake_pid_p, int pid, int
> attached,
>    inf->attach_flag = attached;
>    inf->fake_pid_p = fake_pid_p;
>  
> -  /* If no main executable is currently open then attempt to
> -     open the file that was executed to create this inferior.  */
> -  if (try_open_exec && get_exec_file (0) == NULL)
> +  /* Attempt to open the file that was executed to create this
> +     inferior.  If the user has explicitly specified executable
> +     and/or symbol files then warn the user if their choices do
> +     not match.  Otherwise, set exec_file and symfile_objfile to
> +     the new file.  */
> +  printf("fake_pid_p %d\n", fake_pid_p);
> +  if (try_open_exec)// && !fake_pid_p)
>      exec_file_locate_attach (pid, 1);
> 
> Effectively, the printf shows that with Valgrind gdbsrv,
> fake_pid_p value is 1.
> 
> When ignoring fake_pid_p, GDB can properly attach
> to different Valgrind gdbsrv, and changes of executable
> as expected.

Ah, it seems I mailed a bad patch, my apologies!  I was working on
two fixes that touched the same line, and it looks like I rebased
them in the wrong order.

This updated patch has been created against the latest gdb/master
(80fb91378c91a8239817a5ab2b1c3e346109db25).  Could you please try
your tests again?

Thanks,
Gary

---
On attach, GDB will only attempt to determine the main executable's
filename if one is not already set.  This causes problems if you
attach to one process and then attach to another: GDB will not attempt
to discover the main executable on the second attach.  If the two
processes have different main executable files then the symbols will
now be wrong.  This is PR gdb/17626.

In GDB some filenames are supplied by the user (e.g. using the "file"
or "symbol-file" commands) and some are determined by GDB (e.g. while
processing an "attach" command).  This commit updates GDB to track
which filenames were supplied by the user.  When GDB might attempt to
determine an executable filename and one is already set, filenames
determined by GDB may be overridden but user-supplied filenames will
not.

gdb/ChangeLog:

	PR gdb/17626
	* progspace.h (struct program_space)
	<pspace_exec_file_is_user_supplied>: New field.
	<symfile_object_file_is_user_supplied>: Likewise.
	(symfile_objfile_is_user_supplied): New macro.
	* exec.h (exec_file_is_user_supplied): Likewise.
	* exec.c (exec_close): Clear exec_file_is_user_supplied.
	(exec_file_locate_attach): Remove get_exec_file check.
	Do not replace user-supplied executable or symbol files.
	Warn if user-supplied executable or symbol files do not
	match discovered file.
	(exec_file_command): Set exec_file_is_user_supplied.
	* symfile.c (symbol_file_clear): Clear
	symfile_objfile_is_user_supplied.
	(symbol_file_command): Set symfile_objfile_is_user_supplied.
	* inferior.c (add_inferior_command): Set
	exec_file_is_user_supplied and symfile_objfile_is_user_supplied.
	* main.c (captured_main): Likewise.
	* infcmd.c (attach_command_post_wait): Always call
	exec_file_locate_attach.  Only call reopen_exec_file and
	reread_symbols if exec_file_is_user_supplied.
	* remote.c (remote_add_inferior): Remove get_exec_file check
	around exec_file_locate_attach.
---
 gdb/ChangeLog   |   26 ++++++++++++++++++++++++++
 gdb/exec.c      |   30 +++++++++++++++++++++++-------
 gdb/exec.h      |    2 ++
 gdb/infcmd.c    |   13 ++++++++-----
 gdb/inferior.c  |    3 +++
 gdb/main.c      |   24 ++++++++++++++++--------
 gdb/progspace.h |   17 +++++++++++++++++
 gdb/remote.c    |    9 ++++++---
 gdb/symfile.c   |    3 +++
 9 files changed, 104 insertions(+), 23 deletions(-)

[v3] Make only user-specified executable and symbol filenames sticky

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