Re: [PATCH v2 2/2] Make gdbserver work with filename-only binaries

[Sergio Durigan Junior <sergiodj@redhat.com>]

On Wednesday, February 21 2018, Pedro Alves wrote:

> Hi Sergio,
>
> A few quick comments below.  

Thanks, Pedro, and sorry for the delay in replying.

>> @@ -3539,6 +3564,13 @@ captured_main (int argc, char *argv[])
>>    const char *selftest_filter = NULL;
>>  #endif
>>  
>> +  current_directory = getcwd (NULL, 0);
>> +  if (current_directory == NULL)
>> +    {
>> +      warning (_("%s: error finding working directory"),
>> +	       safe_strerror (errno));
>
> I think it's much more usual to put the strerror string at the
> end of the warning rather than at the beginning.
>
> I.e., something like:
>
>    warning (_("Could not find working directory: %s"),
>        safe_strerror (errno));
>
> See
>
>   $ (cd gdb; git grep -3 "warning (" *.c | grep strerr -C 3)
>
> for example.
>
> From the ongoing discussion, it sounded like this hunk may change
> in the next iteration, but I thought I'd still comment as it
> may help with future patches.

The only change is s/warning/error/, but I can also change the message.

>> +# We only test things locally, and on native-gdbserver
>> +if { [is_remote target] || [is_remote host] || ![use_gdb_stub] } {
>> +    return 0
>> +}
>
>
> I don't see why to restrict this to "only on native-gdbserver".  The test
> is calling gdbserver_start etc. manually, so it should work when testing
> with any local board, I think?  I.e., when testing with native or
> extended-remote too.  For the latter, tests will usually call "disconnect".

As far as I have tested (and remember), extended-remote doesn't actually
start gdbserver by using the binary.  Instead, it starts gdbserver
without a binary and relies on 'set remote exec-file'.

.... (fiddles with testcase) ....

Right, I managed to remove this restriction and now the tests runs and
passes on other target boards as well.

>> +
>> +if { [prepare_for_testing "failed to prepare" $testfile $srcfile debug] } {
>> +    return -1
>> +}
>> +
>> +set target_exec [gdbserver_download_current_prog]
>> +set target_execname [file tail $target_exec]
>> +# We temporarily copy the file to our current directory
>> +file copy -force $target_exec [pwd]
>> +set res [gdbserver_start "" $target_execname]
>
> Please remind me -- is the current directory here usually
> the testcase's output dir?  I.e., is it guaranteed that
> the current directory here is not going to be the same
> directory of another testcase running in parallel at
> the same time?

No, [pwd] is actually the gdb/testsuite/ directory, from where the
Makefile runs.  Which means that other tests running in parallel at the
same time will have the same value for [pwd].  I copied the file to
[pwd] because that's how I solved the problem of having the binary at
the same directory as the one I'm starting gdbserver from.

Another solution that I thought was to cd into the the dirname of
the downloaded $target_exec, execute gdbserver from there, and the cd
back to the original directory.  WDYT?

>> +
>> +set gdbserver_protocol [lindex $res 0]
>> +set gdbserver_gdbport [lindex $res 1]
>> +gdb_target_cmd $gdbserver_protocol $gdbserver_gdbport
>> +
>> +if { [runto_main] } {
>> +    pass "load filename without absolute path"
>> +} else {
>> +    fail "load filename without absolute path"
>> +}
>
> runto_main here looks a bit odd to me.  You're manually connecting
> with gdb_target_cmd, bypassing whatever the current board file
> may want to do, but then you're using a routine that call back
> into the board file to do random things to prepare for running.
>
> I think you should set a breakpoint at main and continue to
> it without using runto_main.  Note how no other test in gdb.server/
> uses runto_main.

Ah, OK.  I'm usually confused about our testsuite when it comes to
remote vs. remote-extended, so thanks for the advice.

Thanks,

-- 
Sergio
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