gdb/testsuite/gdb.base/sigbpt.exp

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