binutils-gdb/gdb/testsuite/gdb.base/sigbpt.exp
2011-01-01 15:34:07 +00:00

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# This testcase is part of GDB, the GNU debugger.
# Copyright 2004, 2005, 2007, 2008, 2009, 2010, 2011
# Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Check that GDB can and only executes single instructions when
# stepping through a sequence of breakpoints interleaved by a signal
# handler.
# This test is known to tickle the following problems: kernel letting
# the inferior execute both the system call, and the instruction
# following, when single-stepping a system call; kernel failing to
# propogate the single-step state when single-stepping the sigreturn
# system call, instead resuming the inferior at full speed; GDB
# doesn't know how to software single-step across a sigreturn
# instruction. Since the kernel problems can be "fixed" using
# software single-step this is KFAILed rather than XFAILed.
if [target_info exists gdb,nosignals] {
verbose "Skipping sigbpt.exp because of nosignals."
continue
}
if $tracelevel {
strace $tracelevel
}
set testfile "sigbpt"
set srcfile ${testfile}.c
set binfile ${objdir}/${subdir}/${testfile}
if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
untested sigbpt.exp
return -1
}
gdb_exit
gdb_start
gdb_reinitialize_dir $srcdir/$subdir
gdb_load ${binfile}
#
# Run to `main' where we begin our tests.
#
if ![runto_main] then {
gdb_suppress_tests
}
# If we can examine what's at memory address 0, it is possible that we
# could also execute it. This could probably make us run away,
# executing random code, which could have all sorts of ill effects,
# especially on targets without an MMU. Don't run the tests in that
# case.
gdb_test_multiple "x 0" "memory at address 0" {
-re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }
-re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }
-re ".*$gdb_prompt $" {
untested "Memory at address 0 is possibly executable"
return
}
}
gdb_test "break keeper"
# Run to bowler, and then single step until there's a SIGSEGV. Record
# the address of each single-step instruction (up to and including the
# instruction that causes the SIGSEGV) in bowler_addrs, and the address
# of the actual SIGSEGV in segv_addr.
# Note: this test detects which signal is received. Usually it is SIGSEGV
# (and we use SIGSEGV in comments) but on Darwin it is SIGBUS.
set bowler_addrs bowler
set segv_addr none
gdb_test {display/i $pc}
gdb_test "advance *bowler" "bowler.*" "advance to the bowler"
set test "stepping to fault"
set signame "SIGSEGV"
gdb_test_multiple "stepi" "$test" {
-re "Program received signal (SIGBUS|SIGSEGV).*pc(\r\n| *) *=> (0x\[0-9a-f\]*).*$gdb_prompt $" {
set signame $expect_out(1,string)
set segv_addr $expect_out(3,string)
pass "$test"
}
-re " .*pc(\r\n| *)=> (0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
send_gdb "stepi\n"
exp_continue
}
}
# Now record the address of the instruction following the faulting
# instruction in bowler_addrs.
set test "get insn after fault"
gdb_test_multiple {x/2i $pc} "$test" {
-re "=> (0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {
set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]
pass "$test"
}
}
# Procedures for returning the address of the instruction before, at
# and after, the faulting instruction.
proc before_segv { } {
global bowler_addrs
return [lindex $bowler_addrs 2]
}
proc at_segv { } {
global bowler_addrs
return [lindex $bowler_addrs 1]
}
proc after_segv { } {
global bowler_addrs
return [lindex $bowler_addrs 0]
}
# Check that the address table and SIGSEGV correspond.
set test "Verify that ${signame} occurs at the last STEPI insn"
if {[string compare $segv_addr [at_segv]] == 0} {
pass "$test"
} else {
fail "$test ($segv_addr [at_segv])"
}
# Check that the inferior is correctly single stepped all the way back
# to a faulting instruction.
proc stepi_out { name args } {
global gdb_prompt
global signame
# Set SIGSEGV to pass+nostop and then run the inferior all the way
# through to the signal handler. With the handler is reached,
# disable SIGSEGV, ensuring that further signals stop the
# inferior. Stops a SIGSEGV infinite loop when a broke system
# keeps re-executing the faulting instruction.
rerun_to_main
gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}"
gdb_test "continue" "keeper.*" "${name}; continue to keeper"
gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}"
# Insert all the breakpoints. To avoid the need to step over
# these instructions, this is delayed until after the keeper has
# been reached.
for {set i 0} {$i < [llength $args]} {incr i} {
gdb_test "break [lindex $args $i]" "Breakpoint.*" \
"${name}; set breakpoint $i of [llength $args]"
}
# Single step our way out of the keeper, through the signal
# trampoline, and back to the instruction that faulted.
set test "${name}; stepi out of handler"
gdb_test_multiple "stepi" "$test" {
-re "Could not insert single-step breakpoint.*$gdb_prompt $" {
setup_kfail gdb/1736 "sparc*-*-openbsd*"
fail "$test (could not insert single-step breakpoint)"
}
-re "keeper.*$gdb_prompt $" {
send_gdb "stepi\n"
exp_continue
}
-re "signal handler.*$gdb_prompt $" {
send_gdb "stepi\n"
exp_continue
}
-re "Program received signal SIGSEGV.*$gdb_prompt $" {
kfail gdb/1702 "$test (executed fault insn)"
}
-re "Breakpoint.*pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {
pass "$test (at breakpoint)"
}
-re "Breakpoint.*pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {
kfail gdb/1702 "$test (executed breakpoint)"
}
-re "pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {
pass "$test"
}
-re "pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {
kfail gdb/1702 "$test (skipped fault insn)"
}
-re "pc(\r\n| *)=> 0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" {
kfail gdb/1702 "$test (corrupt pc)"
}
}
# Clear any breakpoints
for {set i 0} {$i < [llength $args]} {incr i} {
gdb_test "clear [lindex $args $i]" "Deleted .*" \
"${name}; clear breakpoint $i of [llength $args]"
}
}
# Let a signal handler exit, returning to a breakpoint instruction
# inserted at the original fault instruction. Check that the
# breakpoint is hit, and that single stepping off that breakpoint
# executes the underlying fault instruction causing a SIGSEGV.
proc cont_out { name args } {
global gdb_prompt
global signame
# Set SIGSEGV to pass+nostop and then run the inferior all the way
# through to the signal handler. With the handler is reached,
# disable SIGSEGV, ensuring that further signals stop the
# inferior. Stops a SIGSEGV infinite loop when a broke system
# keeps re-executing the faulting instruction.
rerun_to_main
gdb_test "handle ${signame} nostop print pass" ".*" "${name}; pass ${signame}"
gdb_test "continue" "keeper.*" "${name}; continue to keeper"
gdb_test "handle ${signame} stop print nopass" ".*" "${name}; nopass ${signame}"
# Insert all the breakpoints. To avoid the need to step over
# these instructions, this is delayed until after the keeper has
# been reached. Always set a breakpoint at the signal trampoline
# instruction.
set args [concat $args "*[at_segv]"]
for {set i 0} {$i < [llength $args]} {incr i} {
gdb_test "break [lindex $args $i]" "Breakpoint.*" \
"${name}; set breakpoint $i of [llength $args]"
}
# Let the handler return, it should "appear to hit" the breakpoint
# inserted at the faulting instruction. Note that the breakpoint
# instruction wasn't executed, rather the inferior was SIGTRAPed
# with the PC at the breakpoint.
gdb_test "continue" "Breakpoint.*pc(\r\n| *)=> [at_segv] .*" \
"${name}; continue to breakpoint at fault"
# Now single step the faulted instrction at that breakpoint.
gdb_test "stepi" \
"Program received signal ${signame}.*pc(\r\n| *)=> [at_segv] .*" \
"${name}; stepi fault"
# Clear any breakpoints
for {set i 0} {$i < [llength $args]} {incr i} {
gdb_test "clear [lindex $args $i]" "Deleted .*" \
"${name}; clear breakpoint $i of [llength $args]"
}
}
# Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
# breakpoints around the faulting address. In all cases the inferior
# should single-step out of the signal trampoline halting (but not
# executing) the fault instruction.
stepi_out "stepi"
stepi_out "stepi bp before segv" "*[before_segv]"
stepi_out "stepi bp at segv" "*[at_segv]"
stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"
# Try to confuse DECR_PC_AFTER_BREAK architectures by scattering
# breakpoints around the faulting address. In all cases the inferior
# should exit the signal trampoline halting at the breakpoint that
# replaced the fault instruction.
cont_out "cont"
cont_out "cont bp after segv" "*[before_segv]"
cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"