1# This testcase is part of GDB, the GNU debugger. 2 3# Copyright 2004, 2005, 2007 Free Software Foundation, Inc. 4 5# This program is free software; you can redistribute it and/or modify 6# it under the terms of the GNU General Public License as published by 7# the Free Software Foundation; either version 3 of the License, or 8# (at your option) any later version. 9# 10# This program is distributed in the hope that it will be useful, 11# but WITHOUT ANY WARRANTY; without even the implied warranty of 12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13# GNU General Public License for more details. 14# 15# You should have received a copy of the GNU General Public License 16# along with this program. If not, see <http://www.gnu.org/licenses/>. 17 18# Check that GDB can trigger and backtrace SIGSEGV signal stacks 19# caused by both accessing (data) and executing (code) at address 20# zero. 21 22# On function descriptor architectures, a zero descriptor, instead of 23# a NULL pointer, is used. That way the NULL code test always 24# contains a zero code reference. 25 26# For recovery, sigjmp/longjmp are used. 27 28# This also tests backtrace/gdb1476. 29 30if [target_info exists gdb,nosignals] { 31 verbose "Skipping signull.exp because of nosignals." 32 continue 33} 34 35if $tracelevel { 36 strace $tracelevel 37} 38 39set prms_id 0 40set bug_id 0 41 42set testfile "signull" 43set srcfile ${testfile}.c 44set binfile ${objdir}/${subdir}/${testfile} 45if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { 46 untested signull.exp 47 return -1 48} 49 50gdb_exit 51gdb_start 52gdb_reinitialize_dir $srcdir/$subdir 53gdb_load ${binfile} 54 55# 56# Run to `main' where we begin our tests. 57# 58 59if ![runto_main] then { 60 gdb_suppress_tests 61} 62 63# If we can examine what's at memory address 0, it is possible that we 64# could also execute it. This could probably make us run away, 65# executing random code, which could have all sorts of ill effects, 66# especially on targets without an MMU. Don't run the tests in that 67# case. 68 69send_gdb "x 0\n" 70gdb_expect { 71 -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { } 72 -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { } 73 -re ".*$gdb_prompt $" { 74 untested "Memory at address 0 is possibly executable" 75 return 76 } 77} 78 79# If an attempt to call a NULL pointer leaves the inferior in main, 80# then function pointers are descriptors, probe this and remember the 81# result. 82 83gdb_test "set test = code_entry_point" "" "set for function pointer probe" 84set test "probe function pointer" 85set function_pointer code_entry_point 86gdb_test_multiple "continue" "$test" { 87 -re "Program received signal SIGSEGV.*bowler .*$gdb_prompt $" { 88 set function_pointer code_descriptor 89 pass "$test (function descriptor)" 90 } 91 -re "Program received signal SIGSEGV.*0.*$gdb_prompt $" { 92 pass "$test (function entry-point)" 93 } 94} 95 96# Re-start from scratch, breakpoint the bowler so that control is 97# regained after each test, and run up to that. 98rerun_to_main 99gdb_test "break bowler" 100gdb_test "break keeper" 101# By default Stop:Yes Print:Yes Pass:Yes 102gdb_test "handle SIGSEGV" "SIGSEGV.*Yes.*Yes.*Yes.*Segmentation fault" 103 104# For the given signal type, check that: the SIGSEGV occures; a 105# backtrace from the SEGV works; the sigsegv is delivered; a backtrace 106# through the SEGV works. 107 108proc test_segv { name tag bt_from_segv bt_from_keeper } { 109 gdb_test continue "Breakpoint.* bowler.*" "${name}; start with the bowler" 110 # NB: Don't use $tag in the testname - changes across systems. 111 gdb_test "set test = $tag" "" "${name}; select the pointer type" 112 gdb_test continue "Program received signal SIGSEGV.*" \ 113 "${name}; take the SIGSEGV" 114 gdb_test backtrace $bt_from_segv "${name}; backtrace from SIGSEGV" 115 gdb_test continue "Breakpoint.* keeper.*" "${name}; continue to the keeper" 116 gdb_test backtrace $bt_from_keeper "${name}; backtrace from keeper through SIGSEGV" 117} 118 119test_segv "data read" data_read \ 120 {#0 .* bowler .*#1 .* main .*} \ 121 {#0 .* keeper .*#1 .* handler .*#2 .* bowler .*#3 .* main .*} 122test_segv "data write" data_write \ 123 {#0 .* bowler .*#1 .* main .*} \ 124 {#0 .* keeper .*#1 .* handler .*#2 .* bowler .*#3 .* main .*} 125test_segv code $function_pointer \ 126 {#0 .* 0x0+ .*#1 .* bowler .*#2 .* main .*} \ 127 {#0 .* keeper .*#1 .* handler .*#2 .* 0x0+ .*#3 .* bowler .*#4 .* main .*} 128