binutils-gdb/gdb/testsuite/gdb.threads/process-dies-while-detachin...

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# Copyright 2016-2018 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 spawns a few threads that immediately exit the whole
# process. On targets where the debugger needs to detach from each
# thread individually (such as on the Linux kernel), the debugger must
# handle the case of the process exiting while the detach is ongoing.
#
# Similarly, the process can also be killed from outside the debugger
# (e.g., with SIGKILL), _before_ the user requests a detach. The
# debugger must likewise detach gracefully.
#
# The testcase actually builds two variants of the test program:
# single-process, and multi-process. In the multi-process variant,
# the test program forks, and it's the fork child that spawns threads
# that exit just while the process is being detached from. The fork
# parent waits for its child to exit, so if GDB fails to detach from
# the child correctly, the parent hangs. Because continuing the
# parent can mask failure to detach from the child correctly (e.g.,
# due to waitpid(-1,...) calls deep in the target layers managing to
# reap the child), we try immediately detaching from the parent too,
# and observing whether the parent exits via standard output.
#
# Normally, if testing with "target remote" against gdbserver, then
# after detaching from all attached processes, gdbserver exits.
# However, when gdbserver detaches from a process that is its own
# direct child, gdbserver does not exit immediately. Instead it
# "joins" (waits for) the child, only exiting when the child itself
# exits too. Thus, on Linux, if gdbserver fails to detach from the
# zombie child's threads correctly (or rather, reap them), it'll hang,
# because the leader thread will only return an exit status after all
# threads are reaped. We test that as well.
standard_testfile
# Test that GDBserver exits.
proc test_server_exit {} {
global server_spawn_id
set test "server exits"
gdb_expect {
-i $server_spawn_id
eof {
pass $test
wait -i $server_spawn_id
unset server_spawn_id
}
timeout {
fail "$test (timeout)"
}
}
}
# If RESULT is not zero, make the caller return.
proc return_if_fail { result } {
if {$result != 0} {
return -code return
}
}
# Detach from a process, and ensure that it exits after detaching.
# This relies on inferior I/O. INF_OUTPUT_RE is the pattern that
# matches the expected inferior output.
proc detach_and_expect_exit {inf_output_re test} {
global decimal
global gdb_spawn_id
global inferior_spawn_id
global gdb_prompt
return_if_fail [gdb_test_multiple "detach" $test {
-re "Detaching from .*, process $decimal" {
}
}]
# Use an indirect spawn id list, and remove inferior spawn id from
# the expected output as soon as it matches, so that if
# $inf_inferior_spawn_id is $server_spawn_id and we're testing in
# "target remote" mode, the eof caused by gdbserver exiting is
# left for the caller to handle.
global daee_spawn_id_list
set daee_spawn_id_list "$inferior_spawn_id $gdb_spawn_id"
set saw_prompt 0
set saw_inf_exit 0
while { !$saw_prompt || ! $saw_inf_exit } {
# We don't know what order the interesting things will arrive in.
# Using a pattern of the form 'x|y|z' instead of -re x ... -re y
# ... -re z ensures that expect always chooses the match that
# occurs leftmost in the input, and not the pattern appearing
# first in the script that occurs anywhere in the input, so that
# we don't skip anything.
return_if_fail [gdb_test_multiple "" $test {
-i daee_spawn_id_list
-re "($inf_output_re)|($gdb_prompt )" {
if {[info exists expect_out(1,string)]} {
verbose -log "saw inferior exit"
set saw_inf_exit 1
set daee_spawn_id_list "$gdb_spawn_id"
} elseif {[info exists expect_out(2,string)]} {
verbose -log "saw prompt"
set saw_prompt 1
set daee_spawn_id_list "$inferior_spawn_id"
}
array unset expect_out
}
}]
}
pass $test
}
# Run to _exit in the child.
proc continue_to_exit_bp {} {
gdb_breakpoint "_exit" temporary
gdb_continue_to_breakpoint "_exit" ".*_exit.*"
}
# If testing single-process, simply detach from the process.
#
# If testing multi-process, first detach from the child, then detach
# from the parent and confirm that the parent exits, thus ensuring
# we've detached from the child successfully, as the parent hangs in
# its waitpid call otherwise.
#
# If connected with "target remote", make sure gdbserver exits.
#
# CMD indicates what to do with the parent after detaching the child.
# Can be either "detach" to detach, or "continue", to continue to
# exit.
#
# CHILD_EXIT indicates how is the child expected to exit. Can be
# either "normal" for normal exit, or "signal" for killed with signal
# SIGKILL.
#
proc do_detach {multi_process cmd child_exit} {
global decimal
global server_spawn_id
if {$child_exit == "normal"} {
set continue_re "exited normally.*"
set inf_output_re "exited, status=0"
} elseif {$child_exit == "signal"} {
if {$multi_process} {
set continue_re "exited with code 02.*"
} else {
set continue_re "terminated with signal SIGKILL.*"
}
set inf_output_re "signaled, sig=9"
} else {
error "unhandled \$child_exit: $child_exit"
}
set is_remote [expr {[target_info exists gdb_protocol]
&& [target_info gdb_protocol] == "remote"}]
if {$multi_process} {
gdb_test "detach" "Detaching from .*, process $decimal\r\n\\\[Inferior $decimal \\(.*\\) detached\\\]" \
"detach child"
gdb_test "inferior 1" "\[Switching to inferior $decimal\].*" \
"switch to parent"
if {$cmd == "detach"} {
# Make sure that detach works and that the parent process
# exits cleanly.
detach_and_expect_exit $inf_output_re "detach parent"
} elseif {$cmd == "continue"} {
# Make sure that continuing works and that the parent process
# exits cleanly.
gdb_test "continue" $continue_re
} else {
perror "unhandled command: $cmd"
}
} else {
if $is_remote {
set extra "\r\nEnding remote debugging\."
} else {
set extra ""
}
if {$cmd == "detach"} {
gdb_test "detach" "Detaching from .*, process ${decimal}\r\n\\\[Inferior $decimal \\(.*\\) detached\\\]$extra"
} elseif {$cmd == "continue"} {
gdb_test "continue" $continue_re
} else {
perror "unhandled command: $cmd"
}
}
# When connected in "target remote" mode, the server should exit
# when there are no processes left to debug.
if { $is_remote && [info exists server_spawn_id]} {
test_server_exit
}
}
# Test detaching from a process that dies just while GDB is detaching.
proc test_detach {multi_process cmd} {
with_test_prefix "detach" {
global binfile
clean_restart ${binfile}
if ![runto_main] {
fail "can't run to main"
return -1
}
if {$multi_process} {
gdb_test_no_output "set detach-on-fork off"
gdb_test_no_output "set follow-fork-mode child"
}
# Run to _exit in the child.
continue_to_exit_bp
do_detach $multi_process $cmd "normal"
}
}
# Same as test_detach, except set a watchpoint before detaching.
proc test_detach_watch {multi_process cmd} {
with_test_prefix "watchpoint" {
global binfile decimal
clean_restart ${binfile}
if ![runto_main] {
fail "can't run to main"
return -1
}
if {$multi_process} {
gdb_test_no_output "set detach-on-fork off"
gdb_test_no_output "set follow-fork-mode child"
gdb_breakpoint "child_function" temporary
gdb_continue_to_breakpoint "child_function" ".*"
}
# Set a watchpoint in the child.
gdb_test "watch globalvar" ".* watchpoint $decimal: globalvar"
# Continue to the _exit breakpoint. This arms the watchpoint
# registers in all threads. Detaching will thus need to clear
# them out, and handle the case of the thread disappearing
# while doing that (on targets that need to detach from each
# thread individually).
continue_to_exit_bp
do_detach $multi_process $cmd "normal"
}
}
# Test detaching from a process that dies _before_ GDB starts
# detaching.
proc test_detach_killed_outside {multi_process cmd} {
with_test_prefix "killed outside" {
global binfile
clean_restart ${binfile}
if ![runto_main] {
fail "can't run to main"
return -1
}
gdb_test_no_output "set breakpoint always-inserted on"
if {$multi_process} {
gdb_test_no_output "set detach-on-fork off"
gdb_test_no_output "set follow-fork-mode child"
}
# Run to _exit in the child.
continue_to_exit_bp
set childpid [get_integer_valueof "mypid" -1]
if { $childpid == -1 } {
untested "failed to extract child pid"
return -1
}
remote_exec target "kill -9 ${childpid}"
# Give it some time to die.
sleep 2
do_detach $multi_process $cmd "signal"
}
}
# The test proper. MULTI_PROCESS is true if testing the multi-process
# variant.
proc do_test {multi_process cmd} {
global testfile srcfile binfile
if {$multi_process && $cmd == "detach"
&& [target_info exists gdb,noinferiorio]} {
# This requires inferior I/O to tell whether both the parent
# and child exit successfully.
return
}
set binfile [standard_output_file ${testfile}-$multi_process-$cmd]
set options {debug pthreads}
if {$multi_process} {
lappend options "additional_flags=-DMULTIPROCESS"
}
if {[build_executable "failed to build" \
$testfile-$multi_process-$cmd $srcfile $options] == -1} {
return -1
}
test_detach $multi_process $cmd
test_detach_watch $multi_process $cmd
test_detach_killed_outside $multi_process $cmd
}
foreach multi_process {0 1} {
set mode [expr {$multi_process ? "multi-process" : "single-process"}]
foreach cmd {"detach" "continue"} {
with_test_prefix "$mode: $cmd" {
do_test $multi_process $cmd
}
}
}