old-cross-binutils/gdb/testsuite/gdb.base/catch-syscall.exp
Josh Stone bfd09d203f gdb: Improve syscall entry/return tracking on Linux
The existing logic was simply to flip syscall entry/return state when a
syscall trap was seen, and even then only with active 'catch syscall'.
That can get out of sync if 'catch syscall' is toggled at odd times.

This patch updates the entry/return state for all syscall traps,
regardless of catching state, and also updates known syscall state for
other kinds of traps.  Almost all PTRACE_EVENT stops are delivered from
the middle of a syscall, so this can act like an entry.  Every other
kind of ptrace stop is only delivered outside of syscall event pairs, so
marking them ignored ensures the next syscall trap looks like an entry.

Three new test scenarios are added to catch-syscall.exp:

- Disable 'catch syscall' from an entry to deliberately miss the return
  event, then re-enable to make sure a new entry is recognized.

- Enable 'catch syscall' for the first time from a vfork event, which is
  a PTRACE_EVENT_VFORK in the middle of the syscall.  Make sure the next
  syscall event is recognized as the return.

- Make sure entry and return are recognized for an ENOSYS syscall.  This
  is to defeat a common x86 hack that uses the pre-filled ENOSYS return
  value as a sign of being on the entry side.

gdb/ChangeLog:

2015-10-19  Josh Stone  <jistone@redhat.com>

	* linux-nat.c (linux_handle_syscall_trap): Always update entry/
	return state, even when not actively catching syscalls at all.
	(linux_handle_extended_wait): Mark syscall_state like an entry.
	(wait_lwp): Set syscall_state ignored for other traps.
	(linux_nat_filter_event): Likewise.

gdb/testsuite/ChangeLog:

2015-10-19  Josh Stone  <jistone@redhat.com>

	* gdb.base/catch-syscall.c: Include <sched.h>.
	(unknown_syscall): New variable.
	(main): Trigger a vfork and an unknown syscall.
	* gdb.base/catch-syscall.exp (vfork_syscalls): New variable.
	(unknown_syscall_number): Likewise.
	(check_call_to_syscall): Accept an optional syscall pattern.
	(check_return_from_syscall): Likewise.
	(check_continue): Likewise.
	(test_catch_syscall_without_args): Check for vfork and ENOSYS.
	(test_catch_syscall_skipping_return): New test toggling off 'catch
	syscall' to step over the syscall return, then toggling back on.
	(test_catch_syscall_mid_vfork): New test turning on 'catch syscall'
	during a PTRACE_EVENT_VFORK stop, in the middle of a vfork syscall.
	(do_syscall_tests): Call test_catch_syscall_without_args and
	test_catch_syscall_mid_vfork.
	(test_catch_syscall_without_args_noxml): Check for vfork and ENOSYS.
	(fill_all_syscalls_numbers): Initialize unknown_syscall_number.
2015-10-19 17:59:38 -07:00

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# Copyright 1997-2015 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/>.
# This program tests the 'catch syscall' functionality.
#
# It was written by Sergio Durigan Junior <sergiodj@linux.vnet.ibm.com>
# on September/2008.
if { [is_remote target] || ![isnative] } then {
continue
}
# This shall be updated whenever 'catch syscall' is implemented
# on some architecture.
if { ![istarget "x86_64-*-linux*"] && ![istarget "i\[34567\]86-*-linux*"]
&& ![istarget "powerpc-*-linux*"] && ![istarget "powerpc64-*-linux*"]
&& ![istarget "sparc-*-linux*"] && ![istarget "sparc64-*-linux*"]
&& ![istarget "mips*-linux*"] && ![istarget "arm*-linux*"]
&& ![istarget "s390*-linux*"] && ![istarget "aarch64*-*-linux*"] } {
continue
}
standard_testfile
if { [prepare_for_testing ${testfile}.exp $testfile ${testfile}.c] } {
untested catch-syscall.exp
return -1
}
# All (but the last) syscalls from the example code. It is filled in
# proc setup_all_syscalls.
set all_syscalls { }
set all_syscalls_numbers { }
# The last syscall (exit()) does not return, so
# we cannot expect the catchpoint to be triggered
# twice. It is a special case.
set last_syscall "exit_group"
set last_syscall_number { }
set vfork_syscalls "(vfork|clone2?)"
set unknown_syscall_number { }
# Internal procedure used to check if, after issuing a 'catch syscall'
# command (without arguments), the 'info breakpoints' command displays
# that '"any syscall"' is to be caught.
proc check_info_bp_any_syscall {} {
# Verifying that the catchpoint appears in the 'info breakpoints'
# command, but with "<any syscall>".
set thistest "catch syscall appears in 'info breakpoints'"
gdb_test "info breakpoints" ".*catchpoint.*keep y.*syscall \"<any syscall>\".*" $thistest
}
# Internal procedure used to check if, after issuing a 'catch syscall X'
# command (with arguments), the 'info breakpoints' command displays
# that the syscall 'X' is to be caught.
proc check_info_bp_specific_syscall { syscall } {
set thistest "syscall(s) $syscall appears in 'info breakpoints'"
gdb_test "info breakpoints" ".*catchpoint.*keep y.*syscall(\[(\]s\[)\])? (.)?${syscall}(.)?.*" $thistest
}
# Internal procedure used to check if, after issuing a 'catch syscall X'
# command (with many arguments), the 'info breakpoints' command displays
# that the syscalls 'X' are to be caught.
proc check_info_bp_many_syscalls { syscalls } {
set filter_str ""
foreach name $syscalls {
set filter_str "${filter_str}${name}, "
}
set filter_str [ string trimright $filter_str ", " ]
set thistest "syscalls $filter_str appears in 'info breakpoints'"
gdb_test "info breakpoints" ".*catchpoint.*keep y.*syscalls (.)?${filter_str}(.)?.*" $thistest
}
# This procedure checks if there was a call to a syscall. The optional
# pattern can match syscalls that vary in implementation, like vfork.
proc check_call_to_syscall { syscall { pattern "" } } {
global decimal
if { $pattern eq "" } {
set pattern "${syscall}"
}
set thistest "program has called $syscall"
gdb_test "continue" "Catchpoint $decimal \\(call to syscall .?${pattern}.?\\).*" $thistest
}
# This procedure checks if the syscall returned. The optional pattern
# can match syscalls that vary in implementation, like vfork.
proc check_return_from_syscall { syscall { pattern "" } } {
global decimal
if { $pattern eq "" } {
set pattern "${syscall}"
}
set thistest "syscall $syscall has returned"
gdb_test "continue" "Catchpoint $decimal \\(returned from syscall ${pattern}\\).*" $thistest
}
# Internal procedure that performs two 'continue' commands and checks if
# a syscall call AND return occur. The optional pattern can match
# syscalls that vary in implementation, like vfork.
proc check_continue { syscall { pattern "" } } {
# Testing if the 'continue' stops at the
# specified syscall_name. If it does, then it should
# first print that the infeior has called the syscall,
# and after print that the syscall has returned.
# Testing if the inferior has called the syscall.
check_call_to_syscall $syscall $pattern
# And now, that the syscall has returned.
check_return_from_syscall $syscall $pattern
}
# Inserts a syscall catchpoint with an argument.
proc insert_catch_syscall_with_arg { syscall } {
global decimal
# Trying to set the catchpoint
set thistest "catch syscall with arguments ($syscall)"
gdb_test "catch syscall $syscall" "Catchpoint $decimal \\(syscall \'?${syscall}\'?( \[${decimal}\])?\\)" $thistest
check_info_bp_specific_syscall $syscall
}
# Inserts a syscall catchpoint with many arguments.
proc insert_catch_syscall_with_many_args { syscalls numbers } {
global decimal
set catch [ join $syscalls " " ]
set filter_str ""
foreach name $syscalls number $numbers {
set filter_str "${filter_str}'${name}' \\\[${number}\\\] "
}
set filter_str [ string trimright $filter_str " " ]
# Trying to set the catchpoint
set thistest "catch syscall with arguments ($filter_str)"
gdb_test "catch syscall $catch" "Catchpoint $decimal \\(syscalls ${filter_str}\\).*" $thistest
check_info_bp_many_syscalls $syscalls
}
proc check_for_program_end {} {
# Deleting the catchpoints
delete_breakpoints
gdb_continue_to_end
}
proc test_catch_syscall_without_args {} {
global all_syscalls last_syscall vfork_syscalls unknown_syscall_number decimal
with_test_prefix "without arguments" {
# Trying to set the syscall.
gdb_test "catch syscall" "Catchpoint $decimal \\(any syscall\\)"
check_info_bp_any_syscall
# We have to check every syscall.
foreach name $all_syscalls {
check_continue $name
}
check_continue "vfork" $vfork_syscalls
with_test_prefix "ENOSYS" {
check_continue $unknown_syscall_number
}
# At last but not least, we check if the inferior has called
# the last (exit) syscall.
check_call_to_syscall $last_syscall
# Now let's see if the inferior correctly finishes.
check_for_program_end
}
}
proc test_catch_syscall_with_args {} {
with_test_prefix "with arguments" {
set syscall_name "close"
insert_catch_syscall_with_arg $syscall_name
# Can we continue until we catch the syscall?
check_continue $syscall_name
# Now let's see if the inferior correctly finishes.
check_for_program_end
}
}
proc test_catch_syscall_with_many_args {} {
with_test_prefix "with many arguments" {
global all_syscalls all_syscalls_numbers
insert_catch_syscall_with_many_args $all_syscalls $all_syscalls_numbers
# Can we continue until we catch the syscalls?
foreach name $all_syscalls {
check_continue $name
}
# Now let's see if the inferior correctly finishes.
check_for_program_end
}
}
proc test_catch_syscall_with_wrong_args {} {
with_test_prefix "wrong args" {
# mlock is not called from the source
set syscall_name "mlock"
insert_catch_syscall_with_arg $syscall_name
# Now, we must verify if the program stops with a continue.
# If it doesn't, everything is right (since we don't have
# a syscall named "mlock" in it). Otherwise, this is a failure.
set thistest "catch syscall with unused syscall ($syscall_name)"
gdb_continue_to_end $thistest
}
}
proc test_catch_syscall_restarting_inferior {} {
with_test_prefix "restarting inferior" {
set syscall_name "chroot"
with_test_prefix "entry" {
insert_catch_syscall_with_arg $syscall_name
# Let's first reach the entry of the syscall.
check_call_to_syscall $syscall_name
}
with_test_prefix "entry/return" {
# Now, restart the program.
rerun_to_main
# And check for entry/return.
check_continue $syscall_name
# Can we finish?
check_for_program_end
}
}
}
proc test_catch_syscall_skipping_return {} {
with_test_prefix "skipping return" {
with_test_prefix "entry" {
set syscall_name "write"
insert_catch_syscall_with_arg $syscall_name
# Let's first reach the entry of the syscall.
check_call_to_syscall $syscall_name
# Now purposely skip the syscall return.
delete_breakpoints
gdb_test "stepi" ".*" "step over syscall return"
}
# With a naive entry/return toggle, gdb will still think
# the target is due for a syscall return.
with_test_prefix "entry/return" {
set syscall_name "read"
insert_catch_syscall_with_arg $syscall_name
# Check for entry first, then return.
check_continue $syscall_name
# Can we finish?
check_for_program_end
}
}
}
proc test_catch_syscall_mid_vfork {} {
global gdb_prompt decimal vfork_syscalls
with_test_prefix "mid-vfork" {
# Verify that the system supports "catch vfork".
gdb_test "catch vfork" "Catchpoint $decimal \\(vfork\\)" "insert first vfork catchpoint"
gdb_test_multiple "continue" "continue to first vfork catchpoint" {
-re ".*Your system does not support this type\r\nof catchpoint.*$gdb_prompt $" {
unsupported "continue to first vfork catchpoint"
return
}
-re ".*Catchpoint $decimal \\(vforked process $decimal\\).*$gdb_prompt $" {
pass "continue to first vfork catchpoint"
}
}
# Check that we now reach vfork return only.
# (The actual syscall used varies by architecture.)
gdb_test "catch syscall" "Catchpoint $decimal \\(any syscall\\)"
check_return_from_syscall "vfork" $vfork_syscalls
# Can we finish?
check_for_program_end
}
}
proc test_catch_syscall_fail_nodatadir {} {
with_test_prefix "fail no datadir" {
# Sanitizing.
delete_breakpoints
# Make sure GDB doesn't load the syscalls xml from the system
# data directory.
gdb_test "set data-directory /the/path/to/nowhere" \
"Warning: /the/path/to/nowhere: .*"
# Testing to see if we receive a warning when calling "catch
# syscall" without XML support (without datadir).
set thistest "catch syscall displays a warning when there is no XML support"
gdb_test "catch syscall" \
"warning: Could not load the syscall XML file.*warning: GDB will not be able to display syscall names nor to verify if.*any provided syscall numbers are valid.*Catchpoint .*(syscall).*" \
$thistest
# Since the catchpoint was set, we must check if it's present
# in "info breakpoints" output.
check_info_bp_any_syscall
# Sanitizing.
delete_breakpoints
}
}
proc do_syscall_tests {} {
# NOTE: We don't have to point gdb at the correct data-directory.
# For the build tree that is handled by INTERNAL_GDBFLAGS.
# Verify that the 'catch syscall' help is available
set thistest "help catch syscall"
gdb_test "help catch syscall" "Catch system calls.*" $thistest
# Try to set a catchpoint to a nonsense syscall
set thistest "catch syscall to a nonsense syscall is prohibited"
gdb_test "catch syscall nonsense_syscall" "Unknown syscall name .*" $thistest
# Regression test for syscall completer bug.
gdb_test "complete catch syscall close chroo" \
"catch syscall close chroot" \
"complete catch syscall with multiple words"
# Testing the 'catch syscall' command without arguments.
# This test should catch any syscalls.
if [runto_main] then { test_catch_syscall_without_args }
# Testing the 'catch syscall' command with arguments.
# This test should only catch the specified syscall.
if [runto_main] then { test_catch_syscall_with_args }
# Testing the 'catch syscall' command with many arguments.
# This test should catch $all_syscalls.
if [runto_main] then { test_catch_syscall_with_many_args }
# Testing the 'catch syscall' command with WRONG arguments.
# This test should not trigger any catchpoints.
if [runto_main] then { test_catch_syscall_with_wrong_args }
# Testing the 'catch syscall' command during a restart of
# the inferior.
if [runto_main] then { test_catch_syscall_restarting_inferior }
# Testing the 'catch syscall' command toggling off past a
# syscall return, then resuming entry/return as normal.
if [runto_main] then { test_catch_syscall_skipping_return }
# Testing the 'catch syscall' command starting mid-vfork.
if [runto_main] then { test_catch_syscall_mid_vfork }
# Testing if the 'catch syscall' command works when switching to
# different architectures on-the-fly (PR gdb/10737).
if [runto_main] then { test_catch_syscall_multi_arch }
}
proc test_catch_syscall_without_args_noxml {} {
with_test_prefix "without args noxml" {
# We will need the syscall names even not using it because we
# need to know know many syscalls are in the example file.
global decimal all_syscalls last_syscall_number unknown_syscall_number all_syscalls_numbers
delete_breakpoints
gdb_test "catch syscall" "Catchpoint .*(syscall).*"
# Now, we should be able to set a catchpoint, and GDB shall
# not display the warning anymore.
foreach name $all_syscalls number $all_syscalls_numbers {
with_test_prefix "$name" {
check_continue $number
}
}
check_continue "vfork" $decimal
with_test_prefix "ENOSYS" {
check_continue $unknown_syscall_number
}
# At last but not least, we check if the inferior has called
# the last (exit) syscall.
check_call_to_syscall $last_syscall_number
delete_breakpoints
}
}
proc test_catch_syscall_with_args_noxml {} {
with_test_prefix "with args noxml" {
global all_syscalls_numbers
delete_breakpoints
# Inserting all syscalls numbers to be caught
foreach syscall_number $all_syscalls_numbers {
insert_catch_syscall_with_arg $syscall_number
}
# Checking that all syscalls are caught.
foreach syscall_number $all_syscalls_numbers {
check_continue $syscall_number
}
delete_breakpoints
}
}
proc test_catch_syscall_with_wrong_args_noxml {} {
with_test_prefix "with wrong args noxml" {
delete_breakpoints
# Even without XML support, GDB should not accept unknown
# syscall names for the catchpoint.
gdb_test "catch syscall nonsense_syscall" \
"Unknown syscall name .nonsense_syscall.*"
delete_breakpoints
}
}
proc test_catch_syscall_multi_arch {} {
global decimal binfile
if { [istarget "i*86-*-*"] || [istarget "x86_64-*-*"] } {
set arch1 "i386"
set arch2 "i386:x86-64"
set syscall1_name "exit"
set syscall2_name "write"
set syscall_number 1
} elseif { [istarget "powerpc-*-linux*"] \
|| [istarget "powerpc64-*-linux*"] } {
set arch1 "powerpc:common"
set arch2 "powerpc:common64"
set syscall1_name "openat"
set syscall2_name "unlinkat"
set syscall_number 286
} elseif { [istarget "sparc-*-linux*"] \
|| [istarget "sparc64-*-linux*"] } {
set arch1 "sparc"
set arch2 "sparc:v9"
set syscall1_name "setresuid32"
set syscall2_name "setresuid"
set syscall_number 108
} elseif { [istarget "mips*-linux*"] } {
# MIPS does not use the same numbers for syscalls on 32 and 64
# bits.
verbose "Not testing MIPS for multi-arch syscall support"
return
} elseif { [istarget "arm*-linux*"] } {
# catch syscall supports only 32-bit ARM for now.
verbose "Not testing ARM for multi-arch syscall support"
return
} elseif { [istarget "aarch64*-linux*"] } {
set arch1 "aarch64"
set arch2 "arm"
set syscall1_name "reboot"
set syscall2_name "_newselect"
set syscall_number 142
} elseif { [istarget "s390*-linux*"] } {
set arch1 "s390:31-bit"
set arch2 "s390:64-bit"
set syscall1_name "_newselect"
set syscall2_name "select"
set syscall_number 142
}
with_test_prefix "multiple targets" {
# We are not interested in loading any binary here, and in
# some systems (PowerPC, for example), if we load a binary
# there is no way to set other architecture.
gdb_exit
gdb_start
gdb_test "set architecture $arch1" \
"The target architecture is assumed to be $arch1" \
"set arch to $arch1"
gdb_test "catch syscall $syscall_number" \
"Catchpoint $decimal \\(syscall .${syscall1_name}. \\\[${syscall_number}\\\]\\)" \
"insert catch syscall on syscall $syscall_number -- $syscall1_name on $arch1"
gdb_test "set architecture $arch2" \
"The target architecture is assumed to be $arch2" \
"set arch to $arch2"
gdb_test "catch syscall $syscall_number" \
"Catchpoint $decimal \\(syscall .${syscall2_name}. \\\[${syscall_number}\\\]\\)" \
"insert catch syscall on syscall $syscall_number -- $syscall2_name on $arch2"
clean_restart $binfile
}
}
proc do_syscall_tests_without_xml {} {
# Make sure GDB doesn't load the syscalls xml from the system data
# directory.
gdb_test "set data-directory /the/path/to/nowhere" \
"Warning: /the/path/to/nowhere: .*"
# Let's test if we can catch syscalls without XML support.
# We should succeed, but GDB is not supposed to print syscall names.
if [runto_main] then { test_catch_syscall_without_args_noxml }
# The only valid argument "catch syscall" should accept is the
# syscall number, and not the name (since it can't translate a
# name to a number).
if [runto_main] then { test_catch_syscall_with_args_noxml }
# Now, we'll try to provide a syscall name (valid or not) to the command,
# and expect it to fail.
if [runto_main] then { test_catch_syscall_with_wrong_args_noxml }
}
# This procedure fills the vector "all_syscalls_numbers" with the proper
# numbers for the used syscalls according to the architecture.
proc fill_all_syscalls_numbers {} {
global all_syscalls_numbers last_syscall_number unknown_syscall_number all_syscalls
foreach syscall $all_syscalls {
lappend all_syscalls_numbers [get_integer_valueof "${syscall}_syscall" -1]
}
set last_syscall_number [get_integer_valueof "exit_group_syscall" -1]
set unknown_syscall_number [get_integer_valueof "unknown_syscall" -1]
}
# Set up the vector all_syscalls.
proc setup_all_syscalls {} {
global all_syscalls
global gdb_prompt
# They are ordered according to the file, so do not change this.
lappend all_syscalls "close"
lappend all_syscalls "chroot"
# SYS_pipe doesn't exist on aarch64 kernel.
set test "check SYS_pipe"
gdb_test_multiple "p pipe_syscall" $test {
-re " = .*$gdb_prompt $" {
pass $test
lappend all_syscalls "pipe"
}
-re "No symbol .*$gdb_prompt $" {
pass $test
# SYS_pipe isn't defined, use SYS_pipe2 instead.
lappend all_syscalls "pipe2"
}
}
lappend all_syscalls "write"
lappend all_syscalls "read"
}
setup_all_syscalls
# Fill all the syscalls numbers before starting anything.
fill_all_syscalls_numbers
# Execute the tests, using XML support
gdb_exit
if { ![gdb_skip_xml_test] } {
clean_restart $binfile
do_syscall_tests
# Now, we have to see if GDB displays a warning when we
# don't set the data-directory but try to use catch syscall
# anyway. For that, we must restart GDB first.
clean_restart $binfile
test_catch_syscall_fail_nodatadir
}
# Restart gdb
clean_restart $binfile
# Execute the tests, without XML support. In this case, GDB will
# only display syscall numbers, and not syscall names.
do_syscall_tests_without_xml