gdb/testsuite/gdb.base/sigbpt.exp

   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 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 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
  32 if [target_info exists gdb,nosignals] {
  33     verbose "Skipping signals.exp because of nosignals."
  34     continue
  35 }
  36
  37 if $tracelevel {
  38     strace $tracelevel
  39 }
  40
  41 set prms_id 0
  42 set bug_id 0
  43
  44 set testfile "sigbpt"
  45 set srcfile ${testfile}.c
  46 set binfile ${objdir}/${subdir}/${testfile}
  47 if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
  48     untested sigbpt.exp
  49     return -1
  50 }
  51
  52 gdb_exit
  53 gdb_start
  54 gdb_reinitialize_dir $srcdir/$subdir
  55 gdb_load ${binfile}
  56
  57 #
  58 # Run to `main' where we begin our tests.
  59 #
  60
  61 if ![runto_main] then {
  62     gdb_suppress_tests
  63 }
  64
  65 # If we can examine what's at memory address 0, it is possible that we
  66 # could also execute it.  This could probably make us run away,
  67 # executing random code, which could have all sorts of ill effects,
  68 # especially on targets without an MMU.  Don't run the tests in that
  69 # case.
  70
  71 send_gdb "x 0\n"
  72 gdb_expect {
  73     -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }
  74     -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }
  75     -re ".*$gdb_prompt $" {
  76         untested "Memory at address 0 is possibly executable"
  77         return
  78     }
  79 }
  80
  81 gdb_test "break keeper"
  82
  83 # Run to bowler, and then single step until there's a SIGSEGV.  Record
  84 # the address of each single-step instruction (up to and including the
  85 # instruction that causes the SIGSEGV) in bowler_addrs, and the address
  86 # of the actual SIGSEGV in segv_addr.
  87
  88 set bowler_addrs bowler
  89 gdb_test {display/i $pc}
  90 gdb_test "advance *bowler" "bowler.*" "advance to the bowler"
  91 set test "stepping to SIGSEGV"
  92 gdb_test_multiple "stepi" "$test" {
  93     -re "Program received signal SIGSEGV.*pc *(0x\[0-9a-f\]*).*$gdb_prompt $" {
  94         set segv_addr $expect_out(1,string)
  95         pass "$test"
  96     }
  97     -re " .*pc *(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
  98         set bowler_addrs [concat $expect_out(1,string) $bowler_addrs]
  99         send_gdb "stepi\n"
 100         exp_continue
 101     }
 102 }
 103
 104 # Now record the address of the instruction following the faulting
 105 # instruction in bowler_addrs.
 106
 107 set test "get insn after fault"
 108 gdb_test_multiple {x/2i $pc} "$test" {
 109     -re "(0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
 110         set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
 111         pass "$test"
 112     }
 113 }
 114
 115 # Procedures for returning the address of the instruction before, at
 116 # and after, the faulting instruction.
 117
 118 proc before_segv { } {
 119     global bowler_addrs
 120     return [lindex $bowler_addrs 2]
 121 }
 122
 123 proc at_segv { } {
 124     global bowler_addrs
 125     return [lindex $bowler_addrs 1]
 126 }
 127
 128 proc after_segv { } {
 129     global bowler_addrs
 130     return [lindex $bowler_addrs 0]
 131 }
 132
 133 # Check that the address table and SIGSEGV correspond.
 134
 135 set test "Verify that SIGSEGV occurs at the last STEPI insn"
 136 if {[string compare $segv_addr [at_segv]] == 0} {
 137     pass "$test"
 138 } else {
 139     fail "$test ($segv_addr [at_segv])"
 140 }
 141
 142 # Check that the inferior is correctly single stepped all the way back
 143 # to a faulting instruction.
 144
 145 proc stepi_out { name args } {
 146     global gdb_prompt
 147
 148     # Set SIGSEGV to pass+nostop and then run the inferior all the way
 149     # through to the signal handler.  With the handler is reached,
 150     # disable SIGSEGV, ensuring that further signals stop the
 151     # inferior.  Stops a SIGSEGV infinite loop when a broke system
 152     # keeps re-executing the faulting instruction.
 153     rerun_to_main
 154     gdb_test "handle SIGSEGV nostop print pass" "" "${name}; pass SIGSEGV"
 155     gdb_test "continue" "keeper.*" "${name}; continue to keeper"
 156     gdb_test "handle SIGSEGV stop print nopass" "" "${name}; nopass SIGSEGV"
 157
 158     # Insert all the breakpoints.  To avoid the need to step over
 159     # these instructions, this is delayed until after the keeper has
 160     # been reached.
 161     for {set i 0} {$i < [llength $args]} {incr i} {
 162         gdb_test "break [lindex $args $i]" "Breakpoint.*" \
 163             "${name}; set breakpoint $i of [llength $args]"
 164     }
 165
 166     # Single step our way out of the keeper, through the signal
 167     # trampoline, and back to the instruction that faulted.
 168     set test "${name}; stepi out of handler"
 169     gdb_test_multiple "stepi" "$test" {
 170         -re "Could not insert single-step breakpoint.*$gdb_prompt $" {
 171             setup_kfail "sparc*-*-openbsd*" gdb/1736
 172             fail "$test (could not insert single-step breakpoint)"
 173         }
 174         -re "keeper.*$gdb_prompt $" {
 175             send_gdb "stepi\n"
 176             exp_continue
 177         }
 178         -re "signal handler.*$gdb_prompt $" {
 179             send_gdb "stepi\n"
 180             exp_continue
 181         }
 182         -re "Program received signal SIGSEGV.*$gdb_prompt $" {
 183             kfail gdb/1702 "$test (executed fault insn)"
 184         }
 185         -re "Breakpoint.*pc *[at_segv] .*bowler.*$gdb_prompt $" {
 186             pass "$test (at breakpoint)"
 187         }
 188         -re "Breakpoint.*pc *[after_segv] .*bowler.*$gdb_prompt $" {
 189             kfail gdb/1702 "$test (executed breakpoint)"
 190         }
 191         -re "pc *[at_segv] .*bowler.*$gdb_prompt $" {
 192             pass "$test"
 193         }
 194         -re "pc *[after_segv] .*bowler.*$gdb_prompt $" {
 195             kfail gdb/1702 "$test (skipped fault insn)"
 196         }
 197         -re "pc *0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" {
 198             kfail gdb/1702 "$test (corrupt pc)"
 199         }
 200     }
 201
 202     # Clear any breakpoints
 203     for {set i 0} {$i < [llength $args]} {incr i} {
 204         gdb_test "clear [lindex $args $i]" "Deleted .*" \
 205             "${name}; clear breakpoint $i of [llength $args]"
 206     }
 207 }
 208
 209 # Let a signal handler exit, returning to a breakpoint instruction
 210 # inserted at the original fault instruction.  Check that the
 211 # breakpoint is hit, and that single stepping off that breakpoint
 212 # executes the underlying fault instruction causing a SIGSEGV.
 213
 214 proc cont_out { name args } {
 215     global gdb_prompt
 216
 217     # Set SIGSEGV to pass+nostop and then run the inferior all the way
 218     # through to the signal handler.  With the handler is reached,
 219     # disable SIGSEGV, ensuring that further signals stop the
 220     # inferior.  Stops a SIGSEGV infinite loop when a broke system
 221     # keeps re-executing the faulting instruction.
 222     rerun_to_main
 223     gdb_test "handle SIGSEGV nostop print pass" "" "${name}; pass SIGSEGV"
 224     gdb_test "continue" "keeper.*" "${name}; continue to keeper"
 225     gdb_test "handle SIGSEGV stop print nopass" "" "${name}; nopass SIGSEGV"
 226
 227     # Insert all the breakpoints.  To avoid the need to step over
 228     # these instructions, this is delayed until after the keeper has
 229     # been reached.  Always set a breakpoint at the signal trampoline
 230     # instruction.
 231     set args [concat $args "*[at_segv]"]
 232     for {set i 0} {$i < [llength $args]} {incr i} {
 233         gdb_test "break [lindex $args $i]" "Breakpoint.*" \
 234             "${name}; set breakpoint $i  of [llength $args]"
 235     }
 236
 237     # Let the handler return, it should "appear to hit" the breakpoint
 238     # inserted at the faulting instruction.  Note that the breakpoint
 239     # instruction wasn't executed, rather the inferior was SIGTRAPed
 240     # with the PC at the breakpoint.
 241     gdb_test "continue" "Breakpoint.*pc *[at_segv] .*" \
 242         "${name}; continue to breakpoint at fault"
 243
 244     # Now single step the faulted instrction at that breakpoint.
 245     gdb_test "stepi" \
 246         "Program received signal SIGSEGV.*pc *[at_segv] .*" \
 247         "${name}; stepi fault"
 248
 249     # Clear any breakpoints
 250     for {set i 0} {$i < [llength $args]} {incr i} {
 251         gdb_test "clear [lindex $args $i]" "Deleted .*" \
 252             "${name}; clear breakpoint $i of [llength $args]"
 253     }
 254
 255 }
 256
 257
 258
 259 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
 260 # breakpoints around the faulting address.  In all cases the inferior
 261 # should single-step out of the signal trampoline halting (but not
 262 # executing) the fault instruction.
 263
 264 stepi_out "stepi"
 265 stepi_out "stepi bp before segv" "*[before_segv]"
 266 stepi_out "stepi bp at segv" "*[at_segv]"
 267 stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"
 268
 269
 270 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
 271 # breakpoints around the faulting address.  In all cases the inferior
 272 # should exit the signal trampoline halting at the breakpoint that
 273 # replaced the fault instruction.
 274 cont_out "cont"
 275 cont_out "cont bp after segv" "*[before_segv]"
 276 cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"