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authorSergio Durigan Junior <sergiodj@redhat.com>2019-07-10 16:18:27 -0400
committerSergio Durigan Junior <sergiodj@redhat.com>2019-12-13 23:49:29 -0500
commitff8577f64987a898e1dc5eb6afb66a404fb7bb16 (patch)
tree2dbd4a20d96ccb502a73a98b7d8a2e5a417525e8 /gdb/bsd-kvm.c
parente97e2dcd466b43824713e85e307c287b34c8b4bc (diff)
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Guard against 'current_directory == NULL' on gdb_abspath (PR gdb/23613)
Ref.: https://bugzilla.redhat.com/show_bug.cgi?id=1728147 Ref.: https://sourceware.org/bugzilla/show_bug.cgi?id=23613 Hi, This bug has been reported against Fedora GDB, but there's also an upstream bug. The problem reported is that GDB segfaults when the working directory is deleted. It's pretty use to reproduce it: mkdir bla cd bla rmdir ../bla gdb echo Debugging the problem is a bit tricky, because, since the current directory doesn't exist anymore, a corefile cannot be saved there. After a few attempts, I came up with the following: gdb -ex 'shell mkdir bla' -ex 'cd bla' -ex 'shell rmdir ../bla' -ex 'r echo' ./gdb/gdb This assumes that you're inside a build directory which contains ./gdb/gdb, of course. After investigating it, I found that the problem happens at gdb_abspath, where we're dereferencing 'current_directory' without checking if it's NULL: ... (concat (current_directory, IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1]) ? "" : SLASH_STRING, ... So I fixed the problem with the patch below. The idea is that, if 'current_directory' is NULL, then the final string returned should be just the "path". After fixing the bug, I found a similar one reported against our bugzilla: PR gdb/23613. The problem is the same, but the reproducer is a bit different. I really tried writing a testcase for this, but unfortunately it's apparently not possible to start GDB inside a non-existent directory with DejaGNU. I regression tested this patch on the BuildBot, and no regressions were found. gdb/ChangeLog: 2019-12-14 Sergio Durigan Junior <sergiodj@redhat.com> https://bugzilla.redhat.com/show_bug.cgi?id=1728147 PR gdb/23613 * bsd-kvm.c (bsd_kvm_target_open): Use 'gdb_abspath'. * corelow.c: Include 'gdbsupport/pathstuff.h'. (core_target_open): Use 'gdb_abspath'. * gdbsupport/pathstuff.c (gdb_abspath): Guard against 'current_directory == NULL' case. * gdbsupport/pathstuff.h (gdb_abspath): Expand comment and explain what happens when 'current_directory' is NULL. * go32-nat.c (go32_nat_target::wait): Check if 'current_directory' is NULL before call to 'chdir'. * source.c (add_path): Use 'gdb_abspath'. * top.c: Include 'gdbsupport/pathstuff.h'. (init_history): Use 'gdb_abspath'. (set_history_filename): Likewise. * tracefile-tfile.c: Include 'gdbsupport/pathstuff.h'. (tfile_target_open): Use 'gdb_abspath'. Change-Id: Ibb0932fa25bc5c2d3ae4a7f64bd7f32885ca403b
Diffstat (limited to 'gdb/bsd-kvm.c')
-rw-r--r--gdb/bsd-kvm.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/gdb/bsd-kvm.c b/gdb/bsd-kvm.c
index 21f9787..895686e 100644
--- a/gdb/bsd-kvm.c
+++ b/gdb/bsd-kvm.c
@@ -114,14 +114,13 @@ bsd_kvm_target_open (const char *arg, int from_tty)
if (arg)
{
- char *temp;
-
filename = tilde_expand (arg);
if (filename[0] != '/')
{
- temp = concat (current_directory, "/", filename, (char *)NULL);
+ gdb::unique_xmalloc_ptr<char> temp (gdb_abspath (filename));
+
xfree (filename);
- filename = temp;
+ filename = temp.release ();
}
}