Do not crash when calling GDB with empty executable name.

% gdb -q ''

... or ...

        % gdb -q
        (gdb) file ''

... both cause GDB to crash with an invalid free. This is because
exec_file_attach is attempting to free a string that has not been
allocated. The string is only allocated if openp is successful.
But in the case of this obviously invalid filename, openp fails,
and leaves scratch_pathname uninitialized, thus causing the xfree
to fail.

The fix is to enable the associated cleanup after we have verified
that openp was successful.

gdb/ChangeLog (By Keith Seitz  <keiths@redhat.com>):

        * exec.c (exec_file_attach): Move cleanup after verifying that
        memory has in fact been allocated.

gdb/testsuite/ChangeLog:

        * gdb.base/empty_exe.exp: New testcase.
This commit is contained in:
Joel Brobecker 2012-11-26 17:41:44 +00:00
parent 210bbc17ac
commit 17d6efc44b
4 changed files with 37 additions and 2 deletions

View File

@ -1,3 +1,8 @@
2012-11-26 Keith Seitz <keiths@redhat.com>
* exec.c (exec_file_attach): Move cleanup after verifying that
memory has in fact been allocated.
2012-11-26 Tom Tromey <tromey@redhat.com>
* ada-lang.c (user_select_syms): Use SYMBOL_SYMTAB.

View File

@ -225,11 +225,11 @@ exec_file_attach (char *filename, int from_tty)
&scratch_pathname);
}
#endif
if (scratch_chan < 0)
perror_with_name (filename);
cleanups = make_cleanup (xfree, scratch_pathname);
if (scratch_chan < 0)
perror_with_name (filename);
if (write_files)
exec_bfd = gdb_bfd_fopen (scratch_pathname, gnutarget,
FOPEN_RUB, scratch_chan);

View File

@ -1,3 +1,7 @@
2012-11-26 Joel Brobecker <brobecker@adacore.com>
* gdb.base/empty_exe.exp: New testcase.
2012-11-20 Mike Frysinger <vapier@gentoo.org>
* gdb.base/completion.exp: Add test for help aliases completion.

View File

@ -0,0 +1,26 @@
# Copyright 2012 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/>.
gdb_exit
gdb_start
# Make sure that the "file" command rejects an empty filename,
# rather than crash.
gdb_test "file ''" \
": No such file or directory\\."
# And to make extra sure that GDB is still alive, do a quick
# sanity check.
gdb_test "print 1" "= 1"