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# This testcase is part of GDB, the GNU debugger.
# Copyright 2004-2018 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/>.
# Check that GDB can trigger and backtrace SIGSEGV signal stacks
# caused by both accessing (data) and executing (code) at address
# zero.
# On function descriptor architectures, a zero descriptor, instead of
# a NULL pointer, is used. That way the NULL code test always
# contains a zero code reference.
# For recovery, sigjmp/longjmp are used.
# This also tests backtrace/gdb1476.
if [target_info exists gdb,nosignals] {
verbose "Skipping signull.exp because of nosignals."
continue
}
standard_testfile .c
if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
untested "failed to compile"
return -1
}
clean_restart ${binfile}
#
# Run to `main' where we begin our tests.
#
if ![runto_main] then {
gdb_suppress_tests
}
# If we can examine what's at memory address 0, it is possible that we
# could also execute it. This could probably make us run away,
# executing random code, which could have all sorts of ill effects,
# especially on targets without an MMU. Don't run the tests in that
# case.
if { [is_address_zero_readable] } {
untested "memory at address 0 is possibly executable"
return
}
# If an attempt to call a NULL pointer leaves the inferior in main,
# then function pointers are descriptors, probe this and remember the
# result.
gdb_test_no_output "set test = code_entry_point" \
"set for function pointer probe"
set test "probe function pointer"
set function_pointer code_entry_point
set signame "SIGSEGV"
gdb_test_multiple "continue" "$test" {
-re "Program received signal SIGSEGV.*bowler .*$gdb_prompt $" {
set function_pointer code_descriptor
pass "$test (function descriptor)"
}
-re "Program received signal SIGSEGV.*0.*$gdb_prompt $" {
pass "$test (function entry-point)"
}
-re "Program received signal SIGBUS.*0.*$gdb_prompt $" {
set signame SIGBUS
pass "$test (function entry-point)"
}
}
# Re-start from scratch, breakpoint the bowler so that control is
# regained after each test, and run up to that.
rerun_to_main
gdb_test "break bowler"
gdb_test "break keeper"
# By default Stop:Yes Print:Yes Pass:Yes
gdb_test "handle SIGSEGV" "SIGSEGV.*Yes.*Yes.*Yes.*Segmentation fault"
gdb_test "handle SIGBUS" "SIGBUS.*Yes.*Yes.*Yes.*Bus error"
# For the given signal type, check that: the SIGSEGV occures; a
# backtrace from the SEGV works; the sigsegv is delivered; a backtrace
# through the SEGV works.
proc test_segv { name tag bt_from_segv bt_from_keeper } {
global signame
gdb_test continue "Breakpoint.* bowler.*" "${name}; start with the bowler"
# NB: Don't use $tag in the testname - changes across systems.
gdb_test_no_output "set test = $tag" "${name}; select the pointer type"
gdb_test continue "Program received signal ${signame}.*" \
"${name}; take the ${signame}"
gdb_test backtrace $bt_from_segv "${name}; backtrace from ${signame}"
gdb_test continue "Breakpoint.* keeper.*" "${name}; continue to the keeper"
gdb_test backtrace $bt_from_keeper "${name}; backtrace from keeper through ${signame}"
}
test_segv "data read" data_read \
{#0 .* bowler .*#1 .* main .*} \
{#0 .* keeper .*#1 .* handler .*#2 .* bowler .*#3 .* main .*}
test_segv "data write" data_write \
{#0 .* bowler .*#1 .* main .*} \
{#0 .* keeper .*#1 .* handler .*#2 .* bowler .*#3 .* main .*}
test_segv code $function_pointer \
{#0 .* 0x0+ .*#1 .* bowler .*#2 .* main .*} \
{#0 .* keeper .*#1 .* handler .*#2 .* 0x0+ .*#3 .* bowler .*#4 .* main .*}
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