1# This testcase is part of GDB, the GNU debugger.
2
3# Copyright 2004 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 2 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, write to the Free Software
17# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18
19# Check that GDB can trigger and backtrace SIGSEGV signal stacks
20# caused by both accessing (data) and executing (code) at address
21# zero.
22
23# On function descriptor architectures, a zero descriptor, instead of
24# a NULL pointer, is used.  That way the NULL code test always
25# contains a zero code reference.
26
27# For recovery, sigjmp/longjmp are used.
28
29# This also tests backtrace/gdb1476.
30
31if $tracelevel {
32    strace $tracelevel
33}
34
35set prms_id 0
36set bug_id 0
37
38set testfile "signull"
39set srcfile ${testfile}.c
40set binfile ${objdir}/${subdir}/${testfile}
41if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
42    gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
43}
44
45gdb_exit
46gdb_start
47gdb_reinitialize_dir $srcdir/$subdir
48gdb_load ${binfile}
49
50#
51# Run to `main' where we begin our tests.
52#
53
54if ![runto_main] then {
55    gdb_suppress_tests
56}
57
58# If we can examine what's at memory address 0, it is possible that we
59# could also execute it.  This could probably make us run away,
60# executing random code, which could have all sorts of ill effects,
61# especially on targets without an MMU.  Don't run the tests in that
62# case.
63
64send_gdb "x 0\n"
65gdb_expect {
66    -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }
67    -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }
68    -re ".*$gdb_prompt $" {
69	untested "Memory at address 0 is possibly executable"
70	return
71    }
72}
73
74# If an attempt to call a NULL pointer leaves the inferior in main,
75# then function pointers are descriptors, probe this and remember the
76# result.
77
78gdb_test "set test = code_entry_point" "" "set for function pointer probe"
79set test "probe function pointer"
80set function_pointer code_entry_point
81gdb_test_multiple "continue" "$test" {
82    -re "Program received signal SIGSEGV.*bowler .*$gdb_prompt $" {
83	set function_pointer code_descriptor
84	pass "$test (function descriptor)"
85    }
86    -re "Program received signal SIGSEGV.*0.*$gdb_prompt $" {
87	pass "$test (function entry-point)"
88    }
89}
90
91# Re-start from scratch, breakpoint the bowler so that control is
92# regained after each test, and run up to that.
93rerun_to_main
94gdb_test "break bowler"
95gdb_test "break keeper"
96# By default Stop:Yes Print:Yes Pass:Yes
97gdb_test "handle SIGSEGV" "SIGSEGV.*Yes.*Yes.*Yes.*Segmentation fault"
98
99# For the given signal type, check that: the SIGSEGV occures; a
100# backtrace from the SEGV works; the sigsegv is delivered; a backtrace
101# through the SEGV works.
102
103proc test_segv { name tag bt_from_segv bt_from_keeper } {
104    gdb_test continue "Breakpoint.* bowler.*" "${name}; start with the bowler"
105    # NB: Don't use $tag in the testname - changes across systems.
106    gdb_test "set test = $tag" "" "${name}; select the pointer type"
107    gdb_test continue "Program received signal SIGSEGV.*" \
108	"${name}; take the SIGSEGV"
109    gdb_test backtrace $bt_from_segv "${name}; backtrace from SIGSEGV"
110    gdb_test continue "Breakpoint.* keeper.*" "${name}; continue to the keeper"
111    gdb_test backtrace $bt_from_keeper "${name}; backtrace from keeper through SIGSEGV"
112}
113
114test_segv "data read" data_read \
115    {#0 .* bowler .*#1  .* main .*} \
116    {#0 .* keeper .*#1  .* handler .*#2 .* bowler .*#3  .* main .*}
117test_segv "data write" data_write \
118    {#0 .* bowler .*#1  .* main .*} \
119    {#0 .* keeper .*#1  .* handler .*#2 .* bowler .*#3  .* main .*}
120test_segv code $function_pointer \
121    {#0 .* 0x0+ .*#1 .* bowler .*#2  .* main .*} \
122    {#0 .* keeper .*#1  .* handler .*#2 .* 0x0+ .*#3 .* bowler .*#4 .* main .*}
123