Commit 66e8d8be authored by Gary Benson's avatar Gary Benson
Browse files

linux: Add maintenance commands to test libthread_db

This commit adds two new commands which may be used to test thread
debugging libraries used by GDB:

  * "maint check libthread-db" tests the thread debugging library GDB
     is using for the current inferior.

  * "maint set/show check-libthread-db" selects whether libthread_db
     tests should be run automatically as libthread_db is auto-loaded.
     The default is to not run tests automatically.

The test itself is a basic integrity check exercising all libthread_db
functions used by GDB on GNU/Linux systems.  By extension this also
exercises the proc_service functions provided by GDB that libthread_db
uses.

This functionality is useful for NPTL developers and libthread_db
developers.  It could also prove useful investigating bugs reported
against GDB where the thread debugging library or GDB's proc_service
layer is suspect.

gdb/ChangeLog:

	* linux-thread-db.c (valprint.h): New include.
	(struct check_thread_db_info): New structure.
	(check_thread_db_on_load, tdb_testinfo): New static globals.
	(check_thread_db, check_thread_db_callback): New functions.
	(try_thread_db_load_1): Run integrity checks if requested.
	(maintenance_check_libthread_db): New function.
	(_initialize_thread_db): Register "maint check libthread-db"
	and "maint set/show check-libthread-db".

gdb/doc/ChangeLog:

	* gdb.texinfo (Maintenance Commands): Document "maint check
	libthread-db" and "maint set/show check-libthread-db".

gdb/testsuite/ChangeLog:

	* gdb.threads/check-libthread-db.exp: New file.
	* gdb.threads/check-libthread-db.c: Likewise.
parent dc958481
2017-11-22 Gary Benson <gbenson@redhat.com>
* linux-thread-db.c (valprint.h): New include.
(struct check_thread_db_info): New structure.
(check_thread_db_on_load, tdb_testinfo): New static globals.
(check_thread_db, check_thread_db_callback): New functions.
(try_thread_db_load_1): Run integrity checks if requested.
(maintenance_check_libthread_db): New function.
(_initialize_thread_db): Register "maint check libthread-db"
and "maint set/show check-libthread-db".
2017-11-21 Jerome Guitton <guitton@adacore.com>
 
* ravenscar-thread.c (ravenscar_wait): Update inferior ptid
......
2017-11-22 Gary Benson <gbenson@redhat.com>
* gdb.texinfo (Maintenance Commands): Document "maint check
libthread-db" and "maint set/show check-libthread-db".
2017-11-16 Phil Muldoon <pmuldoon@redhat.com>
* python.texi (Basic Python): Add rbreak documentation.
......
......@@ -34981,6 +34981,11 @@ modify XML target descriptions.
Check that the target descriptions dynamically created by @value{GDBN}
equal the descriptions created from XML files found in @var{dir}.
 
@kindex maint check libthread-db
@item maint check libthread-db
Run integrity checks on the current inferior's thread debugging
library.
@kindex maint print dummy-frames
@item maint print dummy-frames
Prints the contents of @value{GDBN}'s internal dummy-frame stack.
......@@ -35288,6 +35293,14 @@ number of blocks in the blockvector
@end enumerate
@end table
 
@kindex maint set check-libthread-db
@kindex maint show check-libthread-db
@item maint set check-libthread-db [on|off]
@itemx maint show check-libthread-db
Control whether @value{GDBN} should run integrity checks on inferior
specific thread debugging libraries as they are loaded. The default
is not to perform such checks.
@kindex maint space
@cindex memory used by commands
@item maint space @var{value}
......@@ -46,6 +46,7 @@
#include <ctype.h>
#include "nat/linux-namespaces.h"
#include <algorithm>
#include "valprint.h"
/* GNU/Linux libthread_db support.
......@@ -80,6 +81,10 @@ static char *libthread_db_search_path;
by the "set auto-load libthread-db" command. */
static int auto_load_thread_db = 1;
/* Set to non-zero if load-time libthread_db tests have been enabled
by the "maintenence set check-libthread-db" command. */
static int check_thread_db_on_load = 0;
/* "show" command for the auto_load_thread_db configuration variable. */
static void
......@@ -493,6 +498,216 @@ dladdr_to_soname (const void *addr)
return NULL;
}
/* State for check_thread_db_callback. */
struct check_thread_db_info
{
/* The libthread_db under test. */
struct thread_db_info *info;
/* True if progress should be logged. */
bool log_progress;
/* True if the callback was called. */
bool threads_seen;
};
static struct check_thread_db_info *tdb_testinfo;
/* Callback for check_thread_db. */
static int
check_thread_db_callback (const td_thrhandle_t *th, void *arg)
{
gdb_assert (tdb_testinfo != NULL);
tdb_testinfo->threads_seen = true;
#define LOG(fmt, args...) \
do \
{ \
if (tdb_testinfo->log_progress) \
{ \
debug_printf (fmt, ## args); \
gdb_flush (gdb_stdlog); \
} \
} \
while (0)
#define __CHECK(expr, args...) \
do \
{ \
if (!(expr)) \
{ \
LOG (" ... FAIL!\n"); \
error (args); \
} \
} \
while (0)
#define CHECK(expr) \
__CHECK (expr, "(%s) == false", #expr)
#define CHECK_CALL(func, args...) \
do \
{ \
td_err_e __err = tdb_testinfo->info->func ## _p (args); \
\
__CHECK (__err == TD_OK, _("%s failed: %s"), #func, \
thread_db_err_str (__err)); \
} \
while (0)
LOG (" Got thread");
/* Check td_ta_thr_iter passed consistent arguments. */
CHECK (th != NULL);
CHECK (arg == (void *) tdb_testinfo);
CHECK (th->th_ta_p == tdb_testinfo->info->thread_agent);
LOG (" %s", core_addr_to_string_nz ((CORE_ADDR) th->th_unique));
/* Check td_thr_get_info. */
td_thrinfo_t ti;
CHECK_CALL (td_thr_get_info, th, &ti);
LOG (" => %d", ti.ti_lid);
CHECK (ti.ti_ta_p == th->th_ta_p);
CHECK (ti.ti_tid == (thread_t) th->th_unique);
/* Check td_ta_map_lwp2thr. */
td_thrhandle_t th2;
memset (&th2, 23, sizeof (td_thrhandle_t));
CHECK_CALL (td_ta_map_lwp2thr, th->th_ta_p, ti.ti_lid, &th2);
LOG (" => %s", core_addr_to_string_nz ((CORE_ADDR) th2.th_unique));
CHECK (memcmp (th, &th2, sizeof (td_thrhandle_t)) == 0);
/* Attempt TLS access. Assuming errno is TLS, this calls
thread_db_get_thread_local_address, which in turn calls
td_thr_tls_get_addr for live inferiors or td_thr_tlsbase
for core files. This test is skipped if the thread has
not been recorded; proceeding in that case would result
in the test having the side-effect of noticing threads
which seems wrong.
Note that in glibc's libthread_db td_thr_tls_get_addr is
a thin wrapper around td_thr_tlsbase; this check always
hits the bulk of the code.
Note also that we don't actually check any libthread_db
calls are made, we just assume they were; future changes
to how GDB accesses TLS could result in this passing
without exercising the calls it's supposed to. */
ptid_t ptid = ptid_build (tdb_testinfo->info->pid, ti.ti_lid, 0);
struct thread_info *thread_info = find_thread_ptid (ptid);
if (thread_info != NULL && thread_info->priv != NULL)
{
LOG ("; errno");
scoped_restore_current_thread restore_current_thread;
switch_to_thread (ptid);
expression_up expr = parse_expression ("errno");
struct value *val = evaluate_expression (expr.get ());
if (tdb_testinfo->log_progress)
{
struct value_print_options opts;
get_user_print_options (&opts);
LOG (" = ");
value_print (val, gdb_stdlog, &opts);
}
}
LOG (" ... OK\n");
#undef LOG
#undef __CHECK
#undef CHECK
#undef CHECK_CALL
return 0;
}
/* Run integrity checks on the dlopen()ed libthread_db described by
INFO. Returns true on success, displays a warning and returns
false on failure. Logs progress messages to gdb_stdlog during
the test if LOG_PROGRESS is true. */
static bool
check_thread_db (struct thread_db_info *info, bool log_progress)
{
bool test_passed = true;
if (log_progress)
debug_printf (_("Running libthread_db integrity checks:\n"));
/* GDB avoids using td_ta_thr_iter wherever possible (see comment
in try_thread_db_load_1 below) so in order to test it we may
have to locate it ourselves. */
td_ta_thr_iter_ftype *td_ta_thr_iter_p = info->td_ta_thr_iter_p;
if (td_ta_thr_iter_p == NULL)
{
void *thr_iter = verbose_dlsym (info->handle, "td_ta_thr_iter");
if (thr_iter == NULL)
return 0;
td_ta_thr_iter_p = (td_ta_thr_iter_ftype *) thr_iter;
}
/* Set up the test state we share with the callback. */
gdb_assert (tdb_testinfo == NULL);
struct check_thread_db_info tdb_testinfo_buf;
tdb_testinfo = &tdb_testinfo_buf;
memset (tdb_testinfo, 0, sizeof (struct check_thread_db_info));
tdb_testinfo->info = info;
tdb_testinfo->log_progress = log_progress;
/* td_ta_thr_iter shouldn't be used on running processes. */
linux_stop_and_wait_all_lwps ();
TRY
{
td_err_e err = td_ta_thr_iter_p (info->thread_agent,
check_thread_db_callback,
tdb_testinfo,
TD_THR_ANY_STATE,
TD_THR_LOWEST_PRIORITY,
TD_SIGNO_MASK,
TD_THR_ANY_USER_FLAGS);
if (err != TD_OK)
error (_("td_ta_thr_iter failed: %s"), thread_db_err_str (err));
if (!tdb_testinfo->threads_seen)
error (_("no threads seen"));
}
CATCH (except, RETURN_MASK_ERROR)
{
if (warning_pre_print)
fputs_unfiltered (warning_pre_print, gdb_stderr);
exception_fprintf (gdb_stderr, except,
_("libthread_db integrity checks failed: "));
test_passed = false;
}
END_CATCH
if (test_passed && log_progress)
debug_printf (_("libthread_db integrity checks passed.\n"));
tdb_testinfo = NULL;
linux_unstop_all_lwps ();
return test_passed;
}
/* Attempt to initialize dlopen()ed libthread_db, described by INFO.
Return 1 on success.
Failure could happen if libthread_db does not have symbols we expect,
......@@ -586,6 +801,13 @@ try_thread_db_load_1 (struct thread_db_info *info)
#undef TDB_DLSYM
#undef CHK
/* Run integrity checks if requested. */
if (check_thread_db_on_load)
{
if (!check_thread_db (info, libthread_db_debug != 0))
return 0;
}
if (info->td_ta_thr_iter_p == NULL)
{
struct lwp_info *lp;
......@@ -1704,6 +1926,24 @@ info_auto_load_libthread_db (const char *args, int from_tty)
uiout->message (_("No auto-loaded libthread-db.\n"));
}
/* Implement 'maintenance check libthread-db'. */
static void
maintenance_check_libthread_db (const char *args, int from_tty)
{
int inferior_pid = ptid_get_pid (inferior_ptid);
struct thread_db_info *info;
if (inferior_pid == 0)
error (_("No inferior running"));
info = get_thread_db_info (inferior_pid);
if (info == NULL)
error (_("No libthread_db loaded"));
check_thread_db (info, true);
}
static void
init_thread_db_ops (void)
{
......@@ -1780,6 +2020,23 @@ This options has security implications for untrusted inferiors."),
Usage: info auto-load libthread-db"),
auto_load_info_cmdlist_get ());
add_cmd ("libthread-db", class_maintenance,
maintenance_check_libthread_db, _("\
Run integrity checks on the current inferior's libthread_db."),
&maintenancechecklist);
add_setshow_boolean_cmd ("check-libthread-db",
class_maintenance,
&check_thread_db_on_load, _("\
Set whether to check libthread_db at load time."), _("\
Show whether to check libthread_db at load time."), _("\
If enabled GDB will run integrity checks on inferior specific libthread_db\n\
as they are loaded."),
NULL,
NULL,
&maintenance_set_cmdlist,
&maintenance_show_cmdlist);
/* Add ourselves to objfile event chain. */
observer_attach_new_objfile (thread_db_new_objfile);
......
2017-11-22 Gary Benson <gbenson@redhat.com>
* gdb.threads/check-libthread-db.exp: New file.
* gdb.threads/check-libthread-db.c: Likewise.
2017-11-21 Ulrich Weigand <uweigand@de.ibm.com>
* gdb.arch/ppc-longdouble.exp: New file.
......
/* This testcase is part of GDB, the GNU debugger.
Copyright 2017 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/>. */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
static void
break_here (void)
{
}
static void *
thread_routine (void *arg)
{
errno = 42;
break_here ();
while (1)
sleep (1);
return NULL;
}
int
main (int argc, char *argv)
{
pthread_t the_thread;
int err;
err = pthread_create (&the_thread, NULL, thread_routine, NULL);
if (err != 0)
{
fprintf (stderr, "pthread_create: %s (%d)\n", strerror (err), err);
exit (EXIT_FAILURE);
}
errno = 23;
err = pthread_join (the_thread, NULL);
if (err != 0)
{
fprintf (stderr, "pthread_join: %s (%d)\n", strerror (err), err);
exit (EXIT_FAILURE);
}
exit (EXIT_SUCCESS);
}
# Copyright 2017 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/>.
# This test only works for native processes on Linux.
if { ![isnative] || [is_remote host] || [target_info exists use_gdb_stub]
|| ![istarget *-linux*] } {
continue
}
standard_testfile
if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \
executable debug] != "" } {
return -1
}
# TEST 1: Manual check with libthread_db not loaded.
clean_restart ${binfile}
gdb_test "maint show check-libthread-db" \
"Whether to check libthread_db at load time is off."
gdb_test_no_output "set stop-on-solib-events 1"
gdb_run_cmd
gdb_test "" \
".*Stopped due to shared library event.*no libraries added or removed.*"
gdb_test "maint check libthread-db" \
"No libthread_db loaded" \
"libpthread.so not loaded"
# TEST 2: Manual check with NPTL uninitialized.
# libthread_db should fake a single thread with th_unique == NULL.
gdb_test "continue" \
".*Stopped due to shared library event.*Inferior loaded .*libpthread.*"
gdb_test_sequence "maint check libthread-db" \
"libpthread.so not initialized (manual)" {
"\[\r\n\]+Running libthread_db integrity checks:"
"\[\r\n\]+\[ \]+Got thread 0x0 => \[0-9\]+ => 0x0 ... OK"
"\[\r\n\]+libthread_db integrity checks passed."
}
# TEST 3: Manual check with NPTL fully operational.
gdb_test_no_output "set stop-on-solib-events 0"
gdb_breakpoint break_here
gdb_continue_to_breakpoint break_here
gdb_test_sequence "maint check libthread-db" \
"libpthread.so fully initialized (manual)" {
"\[\r\n\]+Running libthread_db integrity checks:"
"\[\r\n\]+\[ \]+Got thread 0x\[1-9a-f\]\[0-9a-f\]+ => \[0-9\]+ => 0x\[1-9a-f\]\[0-9a-f\]+; errno = 23 ... OK"
"\[\r\n\]+\[ \]+Got thread 0x\[1-9a-f\]\[0-9a-f\]+ => \[0-9\]+ => 0x\[1-9a-f\]\[0-9a-f\]+; errno = 42 ... OK"
"\[\r\n\]+libthread_db integrity checks passed."
}
# TEST 4: Automated check with NPTL uninitialized.
clean_restart ${binfile}
gdb_test_no_output "maint set check-libthread-db 1"
gdb_test_no_output "set debug libthread-db 1"
gdb_breakpoint break_here
gdb_run_cmd
gdb_test_sequence "" \
"libpthread.so not initialized (automated)" {
"\[\r\n\]+Running libthread_db integrity checks:"
"\[\r\n\]+\[ \]+Got thread 0x0 => \[0-9\]+ => 0x0 ... OK"
"\[\r\n\]+libthread_db integrity checks passed."
"\[\r\n\]+[Thread debugging using libthread_db enabled]"
}
# TEST 5: Automated check with NPTL fully operational.
clean_restart ${binfile}
gdb_test_no_output "maint set check-libthread-db 1"
gdb_test_no_output "set debug libthread-db 1"
set test_spawn_id [spawn_wait_for_attach $binfile]
set testpid [spawn_id_get_pid $test_spawn_id]
gdb_test_sequence "attach $testpid" \
"libpthread.so fully initialized (automated)" {
"\[\r\n\]+Running libthread_db integrity checks:"
"\[\r\n\]+\[ \]+Got thread 0x\[1-9a-f\]\[0-9a-f\]+ => \[0-9\]+ => 0x\[1-9a-f\]\[0-9a-f\]+ ... OK"
"\[\r\n\]+\[ \]+Got thread 0x\[1-9a-f\]\[0-9a-f\]+ => \[0-9\]+ => 0x\[1-9a-f\]\[0-9a-f\]+ ... OK"
"\[\r\n\]+libthread_db integrity checks passed."
"\[\r\n\]+[Thread debugging using libthread_db enabled]"
}
gdb_exit
kill_wait_spawned_process $test_spawn_id
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment