gdb/testsuite/gdb.base/sigbpt.exp

   1 # This testcase is part of GDB, the GNU debugger.
   2
   3 # Copyright 2004-2023 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     return
  34 }
  35
  36
  37 standard_testfile
  38
  39 if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
  40     return -1
  41 }
  42
  43 #
  44 # Run to `main' where we begin our tests.
  45 #
  46
  47 if {![runto_main]} {
  48     return 0
  49 }
  50
  51 # If we can examine what's at memory address 0, it is possible that we
  52 # could also execute it.  This could probably make us run away,
  53 # executing random code, which could have all sorts of ill effects,
  54 # especially on targets without an MMU.  Don't run the tests in that
  55 # case.
  56
  57 if { [is_address_zero_readable] } {
  58     untested "memory at address 0 is possibly executable"
  59     return
  60 }
  61
  62 gdb_test "break keeper"
  63
  64 # Run to bowler, and then single step until there's a SIGSEGV.  Record
  65 # the address of each single-step instruction (up to and including the
  66 # instruction that causes the SIGSEGV) in bowler_addrs, and the address
  67 # of the actual SIGSEGV in segv_addr.
  68 # Note: this test detects which signal is received.  Usually it is SIGSEGV
  69 # (and we use SIGSEGV in comments) but on Darwin it is SIGBUS.
  70
  71 set bowler_addrs bowler
  72 set segv_addr none
  73 gdb_test {display/i $pc}
  74 gdb_test "advance bowler" "bowler.*" "advance to the bowler"
  75 set test "stepping to fault"
  76 set signame "SIGSEGV"
  77 gdb_test_multiple "stepi" "$test" {
  78     -re "Program received signal (SIGBUS|SIGSEGV).*pc(\r\n| *) *=> (0x\[0-9a-f\]*).*$gdb_prompt $" {
  79         set signame $expect_out(1,string)
  80         set segv_addr $expect_out(3,string)
  81         pass "$test"
  82     }
  83     -re " .*pc(\r\n| *)=> (0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
  84         set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
  85         send_gdb "stepi\n"
  86         exp_continue
  87     }
  88 }
  89
  90 # Now record the address of the instruction following the faulting
  91 # instruction in bowler_addrs.
  92
  93 set test "get insn after fault"
  94 gdb_test_multiple {x/2i $pc} "$test" {
  95     -re "=> (0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
  96         set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
  97         pass "$test"
  98     }
  99 }
 100
 101 # Procedures for returning the address of the instruction before, at
 102 # and after, the faulting instruction.
 103
 104 proc before_segv { } {
 105     global bowler_addrs
 106     return [lindex $bowler_addrs 2]
 107 }
 108
 109 proc at_segv { } {
 110     global bowler_addrs
 111     return [lindex $bowler_addrs 1]
 112 }
 113
 114 proc after_segv { } {
 115     global bowler_addrs
 116     return [lindex $bowler_addrs 0]
 117 }
 118
 119 # Check that the address table and SIGSEGV correspond.
 120
 121 set test "verify that ${signame} occurs at the last STEPI insn"
 122 if {[string compare $segv_addr [at_segv]] == 0} {
 123     pass "$test"
 124 } else {
 125     fail "$test ($segv_addr [at_segv])"
 126 }
 127
 128 # Check that the inferior is correctly single stepped all the way back
 129 # to a faulting instruction.
 130
 131 proc stepi_out { name args } {
 132     global gdb_prompt
 133     global signame
 134
 135     # Set SIGSEGV to pass+nostop and then run the inferior all the way
 136     # through to the signal handler.  With the handler is reached,
 137     # disable SIGSEGV, ensuring that further signals stop the
 138     # inferior.  Stops a SIGSEGV infinite loop when a broke system
 139     # keeps re-executing the faulting instruction.
 140     with_test_prefix $name {
 141         rerun_to_main
 142     }
 143     gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}"
 144     gdb_test "continue" "keeper.*" "${name}; continue to keeper"
 145     gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}"
 146
 147     # Insert all the breakpoints.  To avoid the need to step over
 148     # these instructions, this is delayed until after the keeper has
 149     # been reached.
 150     for {set i 0} {$i < [llength $args]} {incr i} {
 151         gdb_test "break [lindex $args $i]" "Breakpoint.*" \
 152             "${name}; set breakpoint $i of [llength $args]"
 153     }
 154
 155     # Single step our way out of the keeper, through the signal
 156     # trampoline, and back to the instruction that faulted.
 157     set test "${name}; stepi out of handler"
 158     gdb_test_multiple "stepi" "$test" {
 159         -re "Could not insert single-step breakpoint.*$gdb_prompt $" {
 160             setup_kfail gdb/8841 "sparc*-*-openbsd*"
 161             fail "$test (could not insert single-step breakpoint)"
 162         }
 163         -re "Cannot insert breakpoint.*Cannot access memory.*$gdb_prompt $" {
 164             setup_kfail gdb/8841 "nios2*-*-linux*"
 165             fail "$test (could not insert single-step breakpoint)"
 166         }
 167         -re "keeper.*$gdb_prompt $" {
 168             send_gdb "stepi\n"
 169             exp_continue
 170         }
 171         -re "signal handler.*$gdb_prompt $" {
 172             send_gdb "stepi\n"
 173             exp_continue
 174         }
 175         -re "Program received signal SIGSEGV.*$gdb_prompt $" {
 176             kfail gdb/8807 "$test (executed fault insn)"
 177         }
 178         -re "Breakpoint.*pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {
 179             pass "$test (at breakpoint)"
 180         }
 181         -re "Breakpoint.*pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {
 182             kfail gdb/8807 "$test (executed breakpoint)"
 183         }
 184         -re "pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {
 185             pass "$test"
 186         }
 187         -re "pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {
 188             kfail gdb/8807 "$test (skipped fault insn)"
 189         }
 190         -re "pc(\r\n| *)=> 0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" {
 191             kfail gdb/8807 "$test (corrupt pc)"
 192         }
 193     }
 194
 195     # Clear any breakpoints
 196     for {set i 0} {$i < [llength $args]} {incr i} {
 197         gdb_test "clear [lindex $args $i]" "Deleted .*" \
 198             "${name}; clear breakpoint $i of [llength $args]"
 199     }
 200 }
 201
 202 # Let a signal handler exit, returning to a breakpoint instruction
 203 # inserted at the original fault instruction.  Check that the
 204 # breakpoint is hit, and that single stepping off that breakpoint
 205 # executes the underlying fault instruction causing a SIGSEGV.
 206
 207 proc cont_out { name args } {
 208     global gdb_prompt
 209     global signame
 210
 211     # Set SIGSEGV to pass+nostop and then run the inferior all the way
 212     # through to the signal handler.  With the handler is reached,
 213     # disable SIGSEGV, ensuring that further signals stop the
 214     # inferior.  Stops a SIGSEGV infinite loop when a broke system
 215     # keeps re-executing the faulting instruction.
 216     with_test_prefix $name {
 217         rerun_to_main
 218     }
 219     gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}"
 220     gdb_test "continue" "keeper.*" "${name}; continue to keeper"
 221     gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}"
 222
 223     # Insert all the breakpoints.  To avoid the need to step over
 224     # these instructions, this is delayed until after the keeper has
 225     # been reached.  Always set a breakpoint at the signal trampoline
 226     # instruction.
 227     set args [concat $args "*[at_segv]"]
 228     for {set i 0} {$i < [llength $args]} {incr i} {
 229         gdb_test "break [lindex $args $i]" "Breakpoint.*" \
 230             "${name}; set breakpoint $i  of [llength $args]"
 231     }
 232
 233     # Let the handler return, it should "appear to hit" the breakpoint
 234     # inserted at the faulting instruction.  Note that the breakpoint
 235     # instruction wasn't executed, rather the inferior was SIGTRAPed
 236     # with the PC at the breakpoint.
 237     gdb_test "continue" "Breakpoint.*pc(\r\n| *)=> [at_segv] .*" \
 238         "${name}; continue to breakpoint at fault"
 239
 240     # Now single step the faulted instrction at that breakpoint.
 241     gdb_test "stepi" \
 242         "Program received signal ${signame}.*pc(\r\n| *)=> [at_segv] .*" \
 243         "${name}; stepi fault"
 244
 245     # Clear any breakpoints
 246     for {set i 0} {$i < [llength $args]} {incr i} {
 247         gdb_test "clear [lindex $args $i]" "Deleted .*" \
 248             "${name}; clear breakpoint $i of [llength $args]"
 249     }
 250
 251 }
 252
 253
 254
 255 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
 256 # breakpoints around the faulting address.  In all cases the inferior
 257 # should single-step out of the signal trampoline halting (but not
 258 # executing) the fault instruction.
 259
 260 stepi_out "stepi"
 261 stepi_out "stepi bp before segv" "*[before_segv]"
 262 stepi_out "stepi bp at segv" "*[at_segv]"
 263 stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"
 264
 265
 266 # Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
 267 # breakpoints around the faulting address.  In all cases the inferior
 268 # should exit the signal trampoline halting at the breakpoint that
 269 # replaced the fault instruction.
 270 cont_out "cont"
 271 cont_out "cont bp after segv" "*[before_segv]"
 272 cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"