old-cross-binutils/gdb/testsuite/gdb.base/hook-stop.exp
Pedro Alves 4c2f2a792a Bail out of processing stop if hook-stop resumes target / changes context
This patch, relative to a tree with
https://sourceware.org/ml/gdb-patches/2015-08/msg00295.html, fixes
issues/crashes that trigger if something unexpected happens during a
hook-stop.

E.g., if the inferior disappears while running the hook-stop, we hit
failed assertions:

 (gdb) define hook-stop
 Type commands for definition of "hook-stop".
 End with a line saying just "end".
 >kill
 >end
 (gdb) si
 Kill the program being debugged? (y or n) [answered Y; input not from terminal]
 /home/pedro/gdb/mygit/build/../src/gdb/thread.c:88: internal-error: inferior_thread: Assertion `tp' failed.
 A problem internal to GDB has been detected,
 further debugging may prove unreliable.
 Quit this debugging session? (y or n)

I noticed that if a hook-stop issues a synchronous execution command,
we print the same stop event twice:

 (gdb) define hook-stop
 Type commands for definition of "hook-stop".
 End with a line saying just "end".
 >si
 >end
 (gdb) si
 0x000000000040074a      42          args[i] = 1; /* Init value.  */  <<<<<<< once
 0x000000000040074a      42          args[i] = 1; /* Init value.  */  <<<<<<< twice
 (gdb)

In MI:

 *stopped,reason="end-stepping-range",frame={addr="0x000000000040074a",func="main",args=[],file="threads.c",fullname="/home/pedro/gdb/tests/threads.c",line="42"},thread-id="1",stopped-threads="all",core="0"
 *stopped,reason="end-stepping-range",frame={addr="0x000000000040074a",func="main",args=[],file="threads.c",fullname="/home/pedro/gdb/tests/threads.c",line="42"},thread-id="1",stopped-threads="all",core="0"
 (gdb)

The fix has GDB stop processing the event if the context changed.  I
don't expect people to be doing crazy things from the hook-stop.
E.g., it gives me headaches to try to come up a proper behavior for
handling a thread change from a hook-stop... (E.g., imagine the
hook-stop does thread N; step, with scheduler-locing on).  I think the
most important bit here is preventing crashes.

The patch adds a new hook-stop.exp test that covers the above and also
merges in the old hook-stop-continue.exp and hook-stop-frame.exp into
the same framework.

gdb/ChangeLog:
2015-09-14  Pedro Alves  <palves@redhat.com>

	* infrun.c (current_stop_id): New global.
	(get_stop_id, new_stop_id): New functions.
	(fetch_inferior_event): Handle normal_stop proceeding the target.
	(struct stop_context): New.
	(save_stop_context, release_stop_context_cleanup)
	(stop_context_changed): New functions.
	(normal_stop): Return true if the hook-stop changes the stop
	context.
	* infrun.h (get_stop_id): Declare.
	(normal_stop): Now returns int.  Add documentation.

gdb/testsuite/ChangeLog:
2015-09-14  Pedro Alves  <palves@redhat.com>

	* gdb.base/hook-stop-continue.c: Delete.
	* gdb.base/hook-stop-continue.exp: Delete.
	* gdb.base/hook-stop-frame.c: Delete.
	* gdb.base/hook-stop-frame.exp: Delete.
	* gdb.base/hook-stop.c: New file.
	* gdb.base/hook-stop.exp: New file.
2015-09-14 15:45:14 +01:00

168 lines
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Text

# Copyright 2009-2015 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/>.
standard_testfile
if { [build_executable ${testfile}.exp "${testfile}" $srcfile {debug nowarnings}] } {
return -1
}
# Define the hook-stop that runs COMMANDS.
proc define_hook_stop {commands} {
set test "define hook-stop command"
gdb_test_multiple "define hook-stop" "$test" {
-re "Type commands for definition of \"hook-stop\".\r\nEnd with a line saying just \"end\".\r\n>$" {
gdb_test "$commands\nend" "" "$test"
}
}
}
# Restart GDB, run to main, set a breakpoint, and define a hook-stop
# that runs COMMANDS. If running to main fails, this returns to the
# caller's caller directly.
proc setup {commands} {
global srcfile binfile
clean_restart $binfile
if ![runto_main] then {
fail "Can't run to main"
return -code return
}
gdb_test "break func" \
"Breakpoint.*at.* file .*$srcfile.*\\." \
"breakpoint line number"
define_hook_stop $commands
}
# Check that the hook-stop runs before the frame is printed.
proc hook_stop_before_frame {} {
with_test_prefix "hook-stop runs before frame print" {
global gdb_prompt
setup "echo \"Hello.\""
set test "run hook-stop"
gdb_test_multiple "continue" "$test" {
-re "\"Hello\\.\"\r\nBreakpo.*func.*set breakpoint here.*${gdb_prompt} $" {
pass $test
}
-re "Breakpo.*func.*set breakpoint here.*\"Hello\\.\".*${gdb_prompt} $" {
fail $test
}
}
}
}
# Check that GDB gracefully handles the case of the inferior dying
# while running the hook-stop.
proc hook_stop_kill {} {
with_test_prefix "hook-stop kills inferior" {
global gdb_prompt
setup "kill"
gdb_test_no_output "set confirm off"
set test "run hook-stop"
gdb_test_multiple "continue" "$test" {
-re "Continuing.\r\n${gdb_prompt} $" {
pass $test
}
}
gdb_test "info threads" "No threads.*"
}
}
# Check that GDB gracefully handles the case of the hook-stop
# continuing the inferior in the foreground.
proc hook_stop_continue_fg {} {
with_test_prefix "hook-stop runs continue" {
global gdb_prompt
setup "if \$do_continue\nset \$do_continue = 0\ncontinue\nend"
gdb_test "print \$do_continue = 1" " = 1"
gdb_test "next" "Breakpoint.*func \\(\\) at .*set breakpoint here \\*/" \
"next triggering hook-stop"
gdb_test "next" "a = 2;" "next no hook-stop"
}
}
# Check that GDB gracefully handles the case of the hook-stop
# continuing the inferior in the background.
proc hook_stop_continue_bg {} {
with_test_prefix "hook-stop runs continue&" {
global gdb_prompt
setup "if \$do_continue\nset \$do_continue = 0\ncontinue&\nend"
gdb_test "print \$do_continue = 1" " = 1"
set test "run hook-stop"
gdb_test_multiple "continue" "$test" {
-re "Continuing.\r\n.*${gdb_prompt} " {
pass $test
}
}
set test "inferior exits normally"
gdb_test_multiple "" "$test" {
-re "exited normally" {
pass $test
}
}
gdb_test "info threads" "No threads.*"
}
}
# Check that GDB gracefully handles the case of the hook-stop running
# "next". GDB used to print the stop event twice.
proc hook_stop_next {} {
with_test_prefix "hook-stop runs next" {
global gdb_prompt
setup "next"
set test "run hook-stop"
gdb_test_multiple "continue" "$test" {
-re "a = 2.*a = 2${gdb_prompt} $" {
fail $test
}
-re "a = 2.*${gdb_prompt} $" {
pass $test
}
}
}
}
hook_stop_before_frame
hook_stop_kill
hook_stop_continue_fg
hook_stop_continue_bg
hook_stop_next