binutils-gdb/gdb/testsuite/gdb.gdb/selftest.exp
Pedro Alves f348d89aec Fix PR gdb/18653: gdb disturbs inferior's inherited signal dispositions
gdb's (or gdbserver's) own signal handling should not interfere with
the signal dispositions their spawned children inherit.  However, it
currently does.  For example, some paths in gdb cause SIGPIPE to be
set to SIG_IGN, and as consequence, the child starts with SIGPIPE to
set to SIG_IGN too, even though gdb was started with SIGPIPE set to
SIG_DFL.

This is because the exec family of functions does not reset the signal
disposition of signals that are set to SIG_IGN:

  http://pubs.opengroup.org/onlinepubs/7908799/xsh/execve.html

  Signals set to the default action (SIG_DFL) in the calling process
  image are set to the default action in the new process
  image. Signals set to be ignored (SIG_IGN) by the calling process
  image are set to be ignored by the new process image. Signals set to
  be caught by the calling process image are set to the default action
  in the new process image (see <signal.h>).

And neither does it reset signal masks or flags.

In order to be transparent, when spawning new child processes to debug
(with "run", etc.), reset signal actions and mask back to what was
originally inherited from gdb/gdbserver's parent, just before execing
the target program to debug.

gdb/ChangeLog:
2016-08-09  Pedro Alves  <palves@redhat.com>

	PR gdb/18653
	* Makefile.in (SFILES): Add
	common/signals-state-save-restore.c.
	(HFILES_NO_SRCDIR): Add common/signals-state-save-restore.h.
	(COMMON_OBS): Add signals-state-save-restore.o.
	(signals-state-save-restore.o): New rule.
	* configure: Regenerate.
	* fork-child.c: Include "signals-state-save-restore.h".
	(fork_inferior): Call restore_original_signals_state.
	* main.c: Include "signals-state-save-restore.h".
	(captured_main): Call save_original_signals_state.
	* common/common.m4: Add sigaction to AC_CHECK_FUNCS checks.
	* common/signals-state-save-restore.c: New file.
	* common/signals-state-save-restore.h: New file.

gdb/gdbserver/ChangeLog:
2016-08-09  Pedro Alves  <palves@redhat.com>

	PR gdb/18653
	* Makefile.in (OBS): Add signals-state-save-restore.o.
	(signals-state-save-restore.o): New rule.
	* config.in: Regenerate.
	* configure: Regenerate.
	* linux-low.c: Include "signals-state-save-restore.h".
	(linux_create_inferior): Call
	restore_original_signals_state.
	* server.c: Include "dispositions-save-restore.h".
	(captured_main): Call save_original_signals_state.

gdb/testsuite/ChangeLog:
2016-08-09  Pedro Alves  <palves@redhat.com>

	PR gdb/18653
	* gdb.base/signals-state-child.c: New file.
	* gdb.base/signals-state-child.exp: New file.
	* gdb.gdb/selftest.exp (do_steps_and_nexts): Add new pattern.
2016-08-09 20:16:20 +01:00

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# Copyright 1988-2016 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 file was written by Rob Savoye. (rob@cygnus.com)
load_lib selftest-support.exp
# Not all of the lines of code near the start of main are executed for
# every machine. Also, optimization may reorder some of the lines.
# So all we do is try to step or next over everything until we get
# to a line that we know is always executed.
proc do_steps_and_nexts {} {
global gdb_prompt
global srcdir
gdb_reinitialize_dir $srcdir/..
set unlikely_line 0
for {set count 0} {$count < 32} {incr count} {
# NOTE: carlton/2002-12-11: The "initial brace" and
# "current_directory initialization" possibilities happen to
# me with GCC 3.1 on i686-pc-linux-gnu when I compile with
# optimization.
gdb_test_multiple "list" "list" {
-re ".*context = \\(struct captured_main_args \\*\\) data.*$gdb_prompt $" {
set description "step over context initialization"
set command "step"
}
-re ".*argc = context->argc.*$gdb_prompt $" {
set description "step over argc initialization"
set command "step"
}
-re ".*argv = context->argv.*$gdb_prompt $" {
set description "step over argv initialization"
set command "step"
}
-re ".*quiet = 0.*$gdb_prompt $" {
set description "step over quiet initialization"
set command "step"
}
-re ".*batch = 0.*$gdb_prompt $" {
set description "step over batch initialization"
set command "step"
}
-re ".*symarg = NULL.*$gdb_prompt $" {
set description "step over symarg initialization"
set command "step"
}
-re ".*execarg = NULL.*$gdb_prompt $" {
set description "step over execarg initialization"
set command "step"
}
-re ".*pidarg = NULL.*$gdb_prompt $" {
set description "step over pidarg initialization"
set command "step"
}
-re ".*corearg = NULL.*$gdb_prompt $" {
set description "step over corearg initialization"
set command "step"
}
-re ".*pid_or_core_arg = NULL.*$gdb_prompt $" {
set description "step over pid_or_core_arg initialization"
set command "step"
}
-re ".*cdarg = NULL.*$gdb_prompt $" {
set description "step over cdarg initialization"
set command "step"
}
-re ".*ttyarg = NULL.*$gdb_prompt $" {
set description "step over ttyarg initialization"
set command "step"
}
-re ".*cmdarg_vec = NULL.*$gdb_prompt $" {
set description "step over cmdarg_vec initialization"
set command "step"
}
-re ".*pre_stat_chain = make_command_stats_cleanup.*$gdb_prompt $" {
set description "next over make_command_stats_cleanup and everything it calls"
set command "next"
}
-re ".*START_PROGRESS.*$gdb_prompt $" {
# Note: ezannoni/2004/02/17: This check should be
# removed, since as of today that source line is not
# in gdb anymore.
set description "next over START_PROGRESS and everything it calls"
set command "next"
}
-re ".*mac_init.*$gdb_prompt $" {
set description "next over mac_init and everything it calls"
set command "next"
}
-re ".*init_malloc.*$gdb_prompt $" {
# gdb 6.2.X is the last gdb which called init_malloc
set description "next over init_malloc and everything it calls"
set command "next"
}
-re ".*lim_at_start.*$gdb_prompt $" {
set description "next over lim_at_start initialization"
set command "next"
}
-re ".*TRY.*$gdb_prompt $" {
set description "next over TRY"
set command "next"
}
-re ".*captured_main \\(args\\);.*$gdb_prompt $" {
set description "step into captured_main (args)"
set command "step"
}
-re ".*count . 0x3.*$gdb_prompt $" {
set description "next over conditional stack alignment code 1"
set command "next"
}
-re ".*if .i != 0.*$gdb_prompt $" {
set description "next over conditional stack alignment code 2"
set command "next"
}
-re ".*alloca .i - 4.*$gdb_prompt $" {
set description "next over conditional stack alignment alloca"
set command "next"
}
-re ".*dirsize = 1.*$gdb_prompt $" {
set description "next over dirsize initialization"
set command "next"
}
-re ".*dirarg = .* xmalloc.*$gdb_prompt $" {
return
}
-re ".*setlocale .LC_MESSAGES,.*$gdb_prompt $" {
set description "next over setlocale LC_MESSAGES"
set command "next"
}
-re ".*setlocale .LC_CTYPE,.*$gdb_prompt $" {
set description "next over setlocale LC_CTYPE"
set command "next"
}
-re ".*bindtextdomain .PACKAGE, LOCALEDIR.;.*$gdb_prompt $" {
set description "next over bindtextdomain"
set command "next"
}
-re ".*textdomain .PACKAGE.;.*$gdb_prompt $" {
set description "next over textdomain PACKAGE"
set command "next"
}
-re ".*bfd_init ..;.*$gdb_prompt $" {
set description "next over bfd_init"
set command "next"
}
-re ".*notice_open_fds ..;.*$gdb_prompt $" {
set description "next over notice_open_fds"
set command "next"
}
-re ".*save_original_signals_state ..;.*$gdb_prompt $" {
set description "next over save_original_signals_state"
set command "next"
}
-re ".*VEC_cleanup .cmdarg_s.*$gdb_prompt $" {
set description "next over cmdarg_s VEC_cleanup"
set command "next"
}
-re "\[0-9\]+\[\t \]+\{\r\n$gdb_prompt $" {
set description "step over initial brace"
set command "step"
}
-re ".*current_directory = gdb_dirbuf.*$gdb_prompt $" {
set description "step over current_directory initialization"
set command "step"
}
-re ".*gdb_sysroot = .*$gdb_prompt $" {
# NOTE: carlton/2003-01-15: More optimization reordering,
# observed on GCC 3.1.
set description "step over gdb_sysroot initialization"
set command "step"
}
-re ".*ndir = 0.*$gdb_prompt $" {
set description "step over ndir initialization"
set command "step"
}
-re ".*instream = stdin.*$gdb_prompt $" {
set description "step over instream initialization"
set command "step"
}
-re ".*getcwd .gdb_dirbuf, sizeof .gdb_dirbuf.*$gdb_prompt $" {
set description "next over getcwd"
set command "next"
}
-re ".*gdb_program_name = xstrdup.*$gdb_prompt $" {
set description "next over xstrdup"
set command "next"
}
-re ".*quit_flag = 0.*$gdb_prompt $" {
set description "step over quit_flag initialization"
set command "step"
}
-re ".*gdb_stdout = stdio_fileopen .stdout.;.*$gdb_prompt $" {
set description "step over gdb_stdout initialization"
set command "step"
}
-re ".*gdb_stderr = stdio_fileopen .stderr.;.*$gdb_prompt $" {
set description "step over gdb_stderr initialization"
set command "step"
}
-re "ui = current_ui.*$gdb_prompt $" {
set description "step over top_level initialization"
set command "step"
}
-re ".*main.c.*No such file or directory.*$gdb_prompt $" {
setup_xfail "rs6000-*-aix3*"
fail "must be able to list source lines"
return
}
-re ".*interpreter_p = xstrdup.*$gdb_prompt $" {
if { $unlikely_line == 0 } {
# This is a GCC optimization bug; a constant has been
# associated with the wrong line number.
setup_xfail "*-*-*" gcc/26475
fail "$description (unlikely line from gcc)"
set unlikely_line 1
}
set description "next over xstrdup"
set command "next"
}
-re ".*$gdb_prompt $" {
# If $description hasn't been set yet, it's likely the file
# has been edited but gdb hasn't been recompiled.
if [info exists description] {
fail "unknown source line (after $description)"
} else {
fail "unknown source line"
}
return
}
default {
fail "unknown source line near main"
return
}
}
gdb_test_multiple "$command" "$description" {
-re ".*No such file or directory.\r\n$gdb_prompt $" {
fail "$description (no source available)"
}
-re ".*A file or directory .* does not exist..\r\n$gdb_prompt $" {
fail "$description (no source available)"
}
-re ".*$gdb_prompt $" {
pass "$description"
}
}
}
}
proc test_with_self { } {
global gdb_prompt
global decimal
global timeout
global inferior_spawn_id
# When GDB is built as a C++ program, disassemble shows the full
# prototype.
set cxx_main_args_re [string_to_regexp "(int, char**)"]
# disassemble yourself
gdb_test "x/10i main" \
"x/10i.*main.*main($cxx_main_args_re)?.$decimal.*main($cxx_main_args_re)?.$decimal.*" \
"Disassemble main"
# We'll need this when we send a ^C to GDB. Need to do it before we
# run the program and gdb starts saving and restoring tty states.
gdb_test "shell stty intr '^C'" ".*" \
"set interrupt character in test_with_self"
# FIXME: If we put this after the run to main, the first list
# command doesn't print the same line as the current line where
# gdb is stopped.
gdb_test_no_output "set listsize 1" "set listsize to 1"
# do we have a version number ?
gdb_test_multiple "print version" "printed version" {
-re ".\[0-9\]+ = .\[0-9.\]+.*$gdb_prompt $" {
pass "printed version as string"
}
-re ".\[0-9\]+ = +0x.*\[0-9.\]+.*$gdb_prompt $" {
pass "printed version as pointer"
}
-re ".\[0-9\]+ = +.+ +0x.*\[0-9.\]+.*$gdb_prompt $" {
pass "printed version with cast"
}
}
do_steps_and_nexts
gdb_test "print \"foo\"" ".\[0-9\]+ = \"foo\"" "print a string"
# do_steps_and_nexts left us ready to execute an xmalloc call,
# so give that a try.
# If we don't actually enter the xmalloc call when we give a
# step command that seems like a genuine bug. It seems to happen
# on most RISC processors.
# NOTE drow/2003-06-22: However, if we step back to the preceding two
# lines, just keep stepping until we enter.
set stepped_back 0
setup_xfail "alpha-*-*" "mips-*-*"
set description "step into xmalloc call"
gdb_test_multiple "step" "$description" {
-re "ncmd = 0;.*$gdb_prompt $" {
set stepped_back 1
send_gdb "step\n"
exp_continue
}
-re ".*cmdarg = .* xmalloc.*$gdb_prompt $" {
set stepped_back 1
send_gdb "step\n"
exp_continue
}
-re "dirsize = 1;.*$gdb_prompt $" {
set stepped_back 1
send_gdb "step\n"
exp_continue
}
-re ".*dirarg = .* xmalloc.*$gdb_prompt $" {
if { $stepped_back == 1 } {
send_gdb "step\n"
exp_continue
} else {
fail "$description"
}
}
-re "xmalloc.*size=.*at.*utils.c.*$gdb_prompt $" {
pass "$description"
}
-re ".*No such file or directory.\r\n$gdb_prompt $" {
pass "$description (no source available)"
}
-re "A file or directory .* does not exist..\r\n$gdb_prompt $" {
pass "$description (no source available)"
}
}
# start the "xgdb" process
if [target_info exists gdb,noinferiorio] {
# With no way to interact with the inferior GDB, all we can do
# is let it run.
send_gdb "continue\n"
# Wait a bit while the inferior gdb gets to its prompt.
sleep 1
} else {
set test "xgdb is at prompt"
gdb_test_multiple "continue" $test {
-i "$inferior_spawn_id"
-re "GNU gdb \[0-9\.\]*.*Copyright \\(C\\) \[0-9\]* Free Software Foundation, Inc.*License GPLv3\\+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.*This is free software: you are free to change and redistribute it.*There is NO WARRANTY, to the extent permitted by law. Type \"show copying\".*and \"show warranty\" for details.*This GDB was configured as .*$gdb_prompt $" {
pass $test
}
}
# set xgdb prompt so we can tell which is which
send_inferior "set prompt (xgdb) \n"
set msg "Set xgdb_prompt"
gdb_test_multiple "" $msg {
-i "$inferior_spawn_id"
-re "\[(\]xgdb\[)\].*\[(\]xgdb\[)\] $" {
pass $msg
}
}
}
# kill the xgdb process
if ![target_info exists gdb,nointerrupts] {
set description "send ^C to child process"
send_gdb "\003"
# "Thread 1" is displayed iff Guile support is linked in.
gdb_expect {
-re "(Thread .*|Program) received signal SIGINT.*$gdb_prompt $" {
pass "$description"
}
-re ".*$gdb_prompt $" {
fail "$description"
}
timeout {
fail "$description (timeout)"
}
}
}
set description "send SIGINT signal to child process"
gdb_test "signal SIGINT" \
"Continuing with signal SIGINT.*" \
"$description"
# Switch back to the GDB thread if Guile support is linked in.
# "signal SIGINT" could also switch the current thread.
gdb_test "thread 1" {\[Switching to thread 1 .*\].*}
# get a stack trace
#
# This fails on some linux systems for unknown reasons. On the
# systems where it fails, sometimes it works fine when run manually.
# The testsuite failures may not be limited to just aout systems.
setup_xfail "i*86-pc-linuxaout-gnu"
set description "backtrace through signal handler"
gdb_test_multiple "backtrace" "$description" {
-re "#0.*(read|poll).*in main \\(.*\\) at .*gdb\\.c.*$gdb_prompt $" {
pass "$description"
}
}
# Restart gdb in case next test expects it to be started already.
return 0
}
do_self_tests captured_main test_with_self