Thanks for working on this. I assume you already saw the new test failures, those should be fixed of course. Besides that I have some more remarks on the patch:
On 12.02.2016 18:52, Henri Verbeet wrote:
Signed-off-by: Henri Verbeet hverbeet@codeweavers.com
dlls/ntdll/signal_i386.c | 14 +++++++++++++- dlls/ntdll/tests/exception.c | 38 +++++++++++++++++++++++--------------- 2 files changed, 36 insertions(+), 16 deletions(-)
diff --git a/dlls/ntdll/signal_i386.c b/dlls/ntdll/signal_i386.c index a3abbff..46f932a 100644 --- a/dlls/ntdll/signal_i386.c +++ b/dlls/ntdll/signal_i386.c @@ -2072,8 +2072,20 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext ) case TRAP_x86_PROTFLT: /* General protection fault */ case TRAP_x86_UNKNOWN: /* Unknown fault code */ {
CONTEXT *win_context = get_exception_context( rec ); WORD err = get_error_code(context);
if (!err && (rec->ExceptionCode = is_privileged_instr( get_exception_context(rec) ))) break;
if (!err && (rec->ExceptionCode = is_privileged_instr( win_context ))) break;if ((err & 7) == 2 && (err >> 3) == 0x2d) /* int $0x2d */{
Int 0x2d is not just a special way to raise a breakpoint, its actually a kernel interface to send commands to the debugger. EAX contains the command value, other registers contain the arguments. An proper implementation is not necessary I guess, but at least for small values of EAX which are assigned to commands we would need better test coverage. Most anti- debugger tricks set EAX = 0 which is not tested at all so far.
win_context->Eip += 3;rec->ExceptionCode = EXCEPTION_BREAKPOINT;rec->ExceptionAddress = (char *)win_context->Eip;rec->NumberParameters = is_wow64 ? 1 : 3;rec->ExceptionInformation[0] = EAX_sig(context);rec->ExceptionInformation[1] = ECX_sig(context);rec->ExceptionInformation[2] = EDX_sig(context);break;} rec->ExceptionCode = EXCEPTION_ACCESS_VIOLATION; rec->NumberParameters = 2; rec->ExceptionInformation[0] = 0;diff --git a/dlls/ntdll/tests/exception.c b/dlls/ntdll/tests/exception.c index d6a610e..57b201a 100644 --- a/dlls/ntdll/tests/exception.c +++ b/dlls/ntdll/tests/exception.c @@ -219,6 +219,11 @@ static const struct exception
{ { 0xf1, 0x90, 0xc3 }, /* icebp; nop; ret */ 1, 1, FALSE, STATUS_SINGLE_STEP, 0 },
- { { 0xb8, 0xb8, 0xb8, 0xb8, 0xb8, /* mov $0xb8b8b8b8, %eax */
0xb9, 0xb9, 0xb9, 0xb9, 0xb9, /* mov $0xb9b9b9b9, %ecx */0xba, 0xba, 0xba, 0xba, 0xba, /* mov $0xbabababa, %edx */0xcd, 0x2d, 0xc3 }, /* int $0x2d; ret */17, 0, FALSE, STATUS_BREAKPOINT, 3, { 0xb8b8b8b8, 0xb9b9b9b9, 0xbabababa } },};
Could you maybe also provide a testcase when a debugger is attached? I would expect that it behaves different then. Actually it should not even produce an exception then because the exception is transparently translated into a debug event, like wine already does for debug strings for example.
static int got_exception; @@ -473,7 +478,7 @@ static DWORD handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *fram CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher ) { const struct exception *except = *(const struct exception **)(frame + 1);
- unsigned int i, entry = except - exceptions;
unsigned int i, parameter_count, entry = except - exceptions;
got_exception++; trace( "exception %u: %x flags:%x addr:%p\n",
@@ -482,20 +487,23 @@ static DWORD handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *fram ok( rec->ExceptionCode == except->status || (except->alt_status != 0 && rec->ExceptionCode == except->alt_status), "%u: Wrong exception code %x/%x\n", entry, rec->ExceptionCode, except->status );
- ok( rec->ExceptionAddress == (char*)code_mem + except->offset,
"%u: Wrong exception address %p/%p\n", entry,rec->ExceptionAddress, (char*)code_mem + except->offset );- if (except->alt_status == 0 || rec->ExceptionCode != except->alt_status)
- {
ok( rec->NumberParameters == except->nb_params,"%u: Wrong number of parameters %u/%u\n", entry, rec->NumberParameters, except->nb_params );- }
- ok( context->Eip == (DWORD_PTR)code_mem + except->offset,
"%u: Unexpected eip %#x/%#lx\n", entry,context->Eip, (DWORD_PTR)code_mem + except->offset );- ok( rec->ExceptionAddress == (char*)context->Eip ||
(rec->ExceptionCode == STATUS_BREAKPOINT && rec->ExceptionAddress == (char*)context->Eip + 1),
I would prefer an exact test for ExceptionAddress here, off-by-one errors in exception handling would be kinda odd.
"%u: Unexpected exception address %p/%p\n", entry,rec->ExceptionAddress, (char*)context->Eip );- if (except->status == STATUS_BREAKPOINT && is_wow64)
parameter_count = 1;- else if (except->alt_status == 0 || rec->ExceptionCode != except->alt_status)
parameter_count = except->nb_params;
- {
ok( rec->NumberParameters == except->alt_nb_params,"%u: Wrong number of parameters %u/%u\n", entry, rec->NumberParameters, except->nb_params );- }
parameter_count = except->alt_nb_params;ok( rec->NumberParameters == parameter_count,
"%u: Unexpected parameter count %u/%u\n", entry, rec->NumberParameters, parameter_count );/* Most CPUs (except Intel Core apparently) report a segment limit violation */ /* instead of page faults for accesses beyond 0xffffffff */
@@ -530,7 +538,7 @@ static DWORD handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *fram
skip_params: /* don't handle exception if it's not the address we expected */
- if (rec->ExceptionAddress != (char*)code_mem + except->offset) return ExceptionContinueSearch;
if (context->Eip != (DWORD_PTR)code_mem + except->offset) return ExceptionContinueSearch;
context->Eip += except->length; return ExceptionContinueExecution;