gdb/testsuite/gdb.base/sigbpt.exp

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