[PATCH v3 2/2] Make gdbserver work with filename-only binaries

[Simon Marchi]

On 2018-02-27 10:27 PM, Sergio Durigan Junior wrote:
> diff --git a/gdb/testsuite/gdb.server/abspath.exp b/gdb/testsuite/gdb.server/abspath.exp
> new file mode 100644
> index 0000000000..beb1d96209
> --- /dev/null
> +++ b/gdb/testsuite/gdb.server/abspath.exp
> @@ -0,0 +1,51 @@
> +# This testcase is part of GDB, the GNU debugger.
> +
> +# Copyright 2018 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Test that gdbserver performs path expansion/adjustment when we
> +# provide just a filename (without any path specifications) to it.
> +
> +load_lib gdbserver-support.exp
> +
> +standard_testfile normal.c
> +
> +if { [skip_gdbserver_tests] } {
> +    return 0
> +}
> +
> +if { [prepare_for_testing "failed to prepare" $testfile $srcfile debug] } {
> +    return -1
> +}
> +
> +# Make sure we're disconnected, in case we're testing with an
> +# extended-remote board, therefore already connected.
> +gdb_test "disconnect" ".*"
> +
> +set target_exec [gdbserver_download_current_prog]
> +
> +# Switch to where $target_exec lives, and execute gdbserver from
> +# there.
> +with_cwd "[file dirname $target_exec]" {
> +    set target_execname [file tail $target_exec]
> +    set res [gdbserver_start "" $target_execname]
> +
> +    set gdbserver_protocol [lindex $res 0]
> +    set gdbserver_gdbport [lindex $res 1]
> +    gdb_target_cmd $gdbserver_protocol $gdbserver_gdbport
> +
> +    gdb_breakpoint main
> +    gdb_test "continue" "Breakpoint $decimal.* main.*" "continue to main"
> +}

The patch LGTM, just a note about the test.

I think this won't work when testing with a remote target (wher gdbserver
is started on another machine.  with_cwd will try to cd into an directory
that exists on the other machine, or an "empty string" directory (I am not sure
what gdbserver_download_current_prog returns), so it will probably crash.

It would complicate the test quite a bit to make it work with a remote
target, and wouldn't add much value: when testing with a remote target,
gdbserver is started with a filename-only argument (that's how I
stumbled on the issue).  So if that breaks, all the other tests will fail.

A counter argument for that would be that the remote board file is subject
to change. if we change it so that it invokes gdbserver by passing
non-filename-only paths, the feature would not be tested anymore...

At the minimum, I think we need to skip this test is target is a remote
one ([is_remote target]).  If you want to go further and make the test
work with a remote target, then go ahead, but I would be fine with
just skipping it.

Simon