1# This testcase is part of GDB, the GNU debugger. 2 3# Copyright 2004, 2005, 2007, 2008, 2009, 2010, 2011 4# Free Software Foundation, Inc. 5 6# This program is free software; you can redistribute it and/or modify 7# it under the terms of the GNU General Public License as published by 8# the Free Software Foundation; either version 3 of the License, or 9# (at your option) any later version. 10# 11# This program is distributed in the hope that it will be useful, 12# but WITHOUT ANY WARRANTY; without even the implied warranty of 13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14# GNU General Public License for more details. 15# 16# You should have received a copy of the GNU General Public License 17# along with this program. If not, see <http://www.gnu.org/licenses/>. 18 19# Check that GDB can and only executes single instructions when 20# stepping through a sequence of breakpoints interleaved by a signal 21# handler. 22 23# This test is known to tickle the following problems: kernel letting 24# the inferior execute both the system call, and the instruction 25# following, when single-stepping a system call; kernel failing to 26# propogate the single-step state when single-stepping the sigreturn 27# system call, instead resuming the inferior at full speed; GDB 28# doesn't know how to software single-step across a sigreturn 29# instruction. Since the kernel problems can be "fixed" using 30# software single-step this is KFAILed rather than XFAILed. 31 32if [target_info exists gdb,nosignals] { 33 verbose "Skipping sigbpt.exp because of nosignals." 34 continue 35} 36 37if $tracelevel { 38 strace $tracelevel 39} 40 41 42set testfile "sigbpt" 43set srcfile ${testfile}.c 44set binfile ${objdir}/${subdir}/${testfile} 45if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { 46 untested sigbpt.exp 47 return -1 48} 49 50gdb_exit 51gdb_start 52gdb_reinitialize_dir $srcdir/$subdir 53gdb_load ${binfile} 54 55# 56# Run to `main' where we begin our tests. 57# 58 59if ![runto_main] then { 60 gdb_suppress_tests 61} 62 63# If we can examine what's at memory address 0, it is possible that we 64# could also execute it. This could probably make us run away, 65# executing random code, which could have all sorts of ill effects, 66# especially on targets without an MMU. Don't run the tests in that 67# case. 68 69gdb_test_multiple "x 0" "memory at address 0" { 70 -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { } 71 -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { } 72 -re ".*$gdb_prompt $" { 73 untested "Memory at address 0 is possibly executable" 74 return 75 } 76} 77 78gdb_test "break keeper" 79 80# Run to bowler, and then single step until there's a SIGSEGV. Record 81# the address of each single-step instruction (up to and including the 82# instruction that causes the SIGSEGV) in bowler_addrs, and the address 83# of the actual SIGSEGV in segv_addr. 84# Note: this test detects which signal is received. Usually it is SIGSEGV 85# (and we use SIGSEGV in comments) but on Darwin it is SIGBUS. 86 87set bowler_addrs bowler 88set segv_addr none 89gdb_test {display/i $pc} 90gdb_test "advance *bowler" "bowler.*" "advance to the bowler" 91set test "stepping to fault" 92set signame "SIGSEGV" 93gdb_test_multiple "stepi" "$test" { 94 -re "Program received signal (SIGBUS|SIGSEGV).*pc(\r\n| *) *=> (0x\[0-9a-f\]*).*$gdb_prompt $" { 95 set signame $expect_out(1,string) 96 set segv_addr $expect_out(3,string) 97 pass "$test" 98 } 99 -re " .*pc(\r\n| *)=> (0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" { 100 set bowler_addrs [concat $expect_out(2,string) $bowler_addrs] 101 send_gdb "stepi\n" 102 exp_continue 103 } 104} 105 106# Now record the address of the instruction following the faulting 107# instruction in bowler_addrs. 108 109set test "get insn after fault" 110gdb_test_multiple {x/2i $pc} "$test" { 111 -re "=> (0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" { 112 set bowler_addrs [concat $expect_out(2,string) $bowler_addrs] 113 pass "$test" 114 } 115} 116 117# Procedures for returning the address of the instruction before, at 118# and after, the faulting instruction. 119 120proc before_segv { } { 121 global bowler_addrs 122 return [lindex $bowler_addrs 2] 123} 124 125proc at_segv { } { 126 global bowler_addrs 127 return [lindex $bowler_addrs 1] 128} 129 130proc after_segv { } { 131 global bowler_addrs 132 return [lindex $bowler_addrs 0] 133} 134 135# Check that the address table and SIGSEGV correspond. 136 137set test "Verify that ${signame} occurs at the last STEPI insn" 138if {[string compare $segv_addr [at_segv]] == 0} { 139 pass "$test" 140} else { 141 fail "$test ($segv_addr [at_segv])" 142} 143 144# Check that the inferior is correctly single stepped all the way back 145# to a faulting instruction. 146 147proc stepi_out { name args } { 148 global gdb_prompt 149 global signame 150 151 # Set SIGSEGV to pass+nostop and then run the inferior all the way 152 # through to the signal handler. With the handler is reached, 153 # disable SIGSEGV, ensuring that further signals stop the 154 # inferior. Stops a SIGSEGV infinite loop when a broke system 155 # keeps re-executing the faulting instruction. 156 rerun_to_main 157 gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}" 158 gdb_test "continue" "keeper.*" "${name}; continue to keeper" 159 gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}" 160 161 # Insert all the breakpoints. To avoid the need to step over 162 # these instructions, this is delayed until after the keeper has 163 # been reached. 164 for {set i 0} {$i < [llength $args]} {incr i} { 165 gdb_test "break [lindex $args $i]" "Breakpoint.*" \ 166 "${name}; set breakpoint $i of [llength $args]" 167 } 168 169 # Single step our way out of the keeper, through the signal 170 # trampoline, and back to the instruction that faulted. 171 set test "${name}; stepi out of handler" 172 gdb_test_multiple "stepi" "$test" { 173 -re "Could not insert single-step breakpoint.*$gdb_prompt $" { 174 setup_kfail gdb/1736 "sparc*-*-openbsd*" 175 fail "$test (could not insert single-step breakpoint)" 176 } 177 -re "keeper.*$gdb_prompt $" { 178 send_gdb "stepi\n" 179 exp_continue 180 } 181 -re "signal handler.*$gdb_prompt $" { 182 send_gdb "stepi\n" 183 exp_continue 184 } 185 -re "Program received signal SIGSEGV.*$gdb_prompt $" { 186 kfail gdb/1702 "$test (executed fault insn)" 187 } 188 -re "Breakpoint.*pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" { 189 pass "$test (at breakpoint)" 190 } 191 -re "Breakpoint.*pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" { 192 kfail gdb/1702 "$test (executed breakpoint)" 193 } 194 -re "pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" { 195 pass "$test" 196 } 197 -re "pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" { 198 kfail gdb/1702 "$test (skipped fault insn)" 199 } 200 -re "pc(\r\n| *)=> 0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" { 201 kfail gdb/1702 "$test (corrupt pc)" 202 } 203 } 204 205 # Clear any breakpoints 206 for {set i 0} {$i < [llength $args]} {incr i} { 207 gdb_test "clear [lindex $args $i]" "Deleted .*" \ 208 "${name}; clear breakpoint $i of [llength $args]" 209 } 210} 211 212# Let a signal handler exit, returning to a breakpoint instruction 213# inserted at the original fault instruction. Check that the 214# breakpoint is hit, and that single stepping off that breakpoint 215# executes the underlying fault instruction causing a SIGSEGV. 216 217proc cont_out { name args } { 218 global gdb_prompt 219 global signame 220 221 # Set SIGSEGV to pass+nostop and then run the inferior all the way 222 # through to the signal handler. With the handler is reached, 223 # disable SIGSEGV, ensuring that further signals stop the 224 # inferior. Stops a SIGSEGV infinite loop when a broke system 225 # keeps re-executing the faulting instruction. 226 rerun_to_main 227 gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}" 228 gdb_test "continue" "keeper.*" "${name}; continue to keeper" 229 gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}" 230 231 # Insert all the breakpoints. To avoid the need to step over 232 # these instructions, this is delayed until after the keeper has 233 # been reached. Always set a breakpoint at the signal trampoline 234 # instruction. 235 set args [concat $args "*[at_segv]"] 236 for {set i 0} {$i < [llength $args]} {incr i} { 237 gdb_test "break [lindex $args $i]" "Breakpoint.*" \ 238 "${name}; set breakpoint $i of [llength $args]" 239 } 240 241 # Let the handler return, it should "appear to hit" the breakpoint 242 # inserted at the faulting instruction. Note that the breakpoint 243 # instruction wasn't executed, rather the inferior was SIGTRAPed 244 # with the PC at the breakpoint. 245 gdb_test "continue" "Breakpoint.*pc(\r\n| *)=> [at_segv] .*" \ 246 "${name}; continue to breakpoint at fault" 247 248 # Now single step the faulted instrction at that breakpoint. 249 gdb_test "stepi" \ 250 "Program received signal ${signame}.*pc(\r\n| *)=> [at_segv] .*" \ 251 "${name}; stepi fault" 252 253 # Clear any breakpoints 254 for {set i 0} {$i < [llength $args]} {incr i} { 255 gdb_test "clear [lindex $args $i]" "Deleted .*" \ 256 "${name}; clear breakpoint $i of [llength $args]" 257 } 258 259} 260 261 262 263# Try to confuse DECR_PC_AFTER_BREAK architectures by scattering 264# breakpoints around the faulting address. In all cases the inferior 265# should single-step out of the signal trampoline halting (but not 266# executing) the fault instruction. 267 268stepi_out "stepi" 269stepi_out "stepi bp before segv" "*[before_segv]" 270stepi_out "stepi bp at segv" "*[at_segv]" 271stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]" 272 273 274# Try to confuse DECR_PC_AFTER_BREAK architectures by scattering 275# breakpoints around the faulting address. In all cases the inferior 276# should exit the signal trampoline halting at the breakpoint that 277# replaced the fault instruction. 278cont_out "cont" 279cont_out "cont bp after segv" "*[before_segv]" 280cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]" 281