[2/2] Test GDB connection to GDBserver with no symbol files

This test exercises the scenario where we attempt to connect GDB to GDBserver
in standard remote mode, query the symbol file path, attempt to open said
symbol file on GDB's end and fail, causing the connection to drop abruptly.

I wish i could make all the other PASSes go away and only keep the last test,
as that is the most important one.  As it is, we get full passes for a patched
GDB and 3 PASS/1 FAIL for an unpatched GDB.

Regression-tested on x86-64/Ubuntu.

gdb/testsuite/ChangeLog:

2016-02-24  Luis Machado  <lgustavo@codesourcery.com>

	* gdb.server/attach-with-no-symbol.c: New file.
	* gdb.server/attach-with-no-symbol.exp: New file.
---
 gdb/testsuite/gdb.server/attach-with-no-symbol.c   | 25 ++++++++
 gdb/testsuite/gdb.server/attach-with-no-symbol.exp | 68 ++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 gdb/testsuite/gdb.server/attach-with-no-symbol.c
 create mode 100644 gdb/testsuite/gdb.server/attach-with-no-symbol.exp

On 02/24/2016 02:26 PM, Luis Machado wrote:
> This test exercises the scenario where we attempt to connect GDB to GDBserver
> in standard remote mode, query the symbol file path, attempt to open said
> symbol file on GDB's end and fail, causing the connection to drop abruptly.
> 
> I wish i could make all the other PASSes go away and only keep the last test,
> as that is the most important one.  

You can pass an empty string as test message to gdb_test, etc. to suppress it,
but I don't like doing that, because then if one of those setup steps fails,
it fails silently.  I think that if we want to make that work nicely, it
should be based on scoping the setup steps with something similar to
with_test_prefix:

setup_tests_scope {
   gdb_test_no_output "set sysroot" "clear sysroot"
   ...
}

gdb_test ... "real test"

Tests run within setup_tests_scope scope would pass silently, but fail
loudly.

> 
> diff --git a/gdb/testsuite/gdb.server/attach-with-no-symbol.exp b/gdb/testsuite/gdb.server/attach-with-no-symbol.exp
> new file mode 100644
> index 0000000..a6d0d85
> --- /dev/null
> +++ b/gdb/testsuite/gdb.server/attach-with-no-symbol.exp

I think this should be "connect", not "attach".

> @@ -0,0 +1,68 @@
> +# This testcase is part of GDB, the GNU debugger.
> +
> +# Copyright 2016 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 GDB's ability to properly connect to GDBserver with no pre-opened
> +# symbol file.  If GDB is buggy, it will drop the connection when
> +# it attempts to open the symbol file indicated by GDBserver and fails.
> +#
> +# This test is only meaningful for standard remote connections.
> +
> +load_lib gdbserver-support.exp
> +
> +standard_testfile
> +
> +if { [skip_gdbserver_tests] } {
> +    return 0
> +}
> +
> +if { [prepare_for_testing $testfile.exp $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" ".*"
> +
> +# Discard any symbol files that we have opened.
> +gdb_test "file" ".*" "Discard symbol table" \
> +    {Discard symbol table from `.*'\? \(y or n\) } "y"
> +
> +set target_exec [gdbserver_download_current_prog]
> +
> +# Start GDBserver.
> +set res [gdbserver_start "" $target_exec]
> +
> +set gdbserver_protocol [lindex $res 0]
> +set gdbserver_gdbport [lindex $res 1]
> +
> +# Prevent access to the symbol file.
> +if {[file exists $binfile]} {
> +    system "chmod 000 $binfile"
> +}

Seems like this won't work with remote-host testing?

> +
> +# Set sysroot to something non-target and possibly also invalid so that GDB is
> +# unable to open the symbol file.
> +gdb_test_no_output "set sysroot" "Disable downloading of symbol files"

It's more usual for test messages to start with lower case.

> +
> +# Connect to GDBserver.
> +gdb_target_cmd $gdbserver_protocol $gdbserver_gdbport
> +
> +# Check if GDB succeeded connecting to GDBserver by attempting to detach from
> +# the process.
> +gdb_test "detach" \
> +	 ".*Detaching from program: , process.*Ending remote debugging.*" \
> +	 "Connection to GDBserver succeeded"
> 

Likewise.

How about moving the body of the test to a procedure, and then
also testing deleting the file instead of making it unreadable?

Wouldn't the chmod make gdb also fail to load the file with the default
target: sysroot, since gdbserver would fail to read it?  I think
that should also be a test axis.

Thanks,
Pedro Alves