[PATCH v2 1/3] ntdll: Allow raising second chance exceptions from signal handlers.
Paul Gofman
pgofman at codeweavers.com
Mon Dec 6 08:18:36 CST 2021
Do I understand correctly that the main purpose of these patches is to
provide the debugger an opportunity to see (and potentially handle)
second chance exception? As it probably doesn't matter too much how
exactly the process will fail after second chance exception in the
absence of debugger. In any case, that probably deserves some debugger
tests? The majority of existing debugger tests is in
ntdll/tests/exception.c:test_debugger().
On 12/6/21 16:55, Jinoh Kang wrote:
> This is required to implement some instructions that raise second chance
> exceptions directly, such as those emitted from the __fastfail()
> intrinsic function.
>
> Signed-off-by: Jinoh Kang <jinoh.kang.kr at gmail.com>
> ---
>
> Notes:
> v1 -> v2: proper patch splitting
>
> dlls/ntdll/unix/signal_arm.c | 18 ++++++++++++------
> dlls/ntdll/unix/signal_arm64.c | 22 ++++++++++++++--------
> dlls/ntdll/unix/signal_i386.c | 21 ++++++++++++++-------
> dlls/ntdll/unix/signal_x86_64.c | 18 ++++++++++++------
> dlls/ntdll/unix/thread.c | 28 +++++++++++++++++++---------
> dlls/ntdll/unix/unix_private.h | 1 +
> 6 files changed, 72 insertions(+), 36 deletions(-)
>
> diff --git a/dlls/ntdll/unix/signal_arm.c b/dlls/ntdll/unix/signal_arm.c
> index ebc08984adf..dbc2770f72e 100644
> --- a/dlls/ntdll/unix/signal_arm.c
> +++ b/dlls/ntdll/unix/signal_arm.c
> @@ -576,7 +576,7 @@ __ASM_GLOBAL_FUNC( raise_func_trampoline,
> *
> * Modify the signal context to call the exception raise function.
> */
> -static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
> +static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec, BOOL first_chance )
> {
> struct
> {
> @@ -591,13 +591,19 @@ static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
> rec->ExceptionAddress = (void *)PC_sig(sigcontext);
> save_context( &context, sigcontext );
>
> - status = send_debug_event( rec, &context, TRUE );
> + status = send_debug_event( rec, &context, first_chance );
> if (status == DBG_CONTINUE || status == DBG_EXCEPTION_HANDLED)
> {
> restore_context( &context, sigcontext );
> return;
> }
>
> + if (!first_chance)
> + {
> + handle_second_chance_exception( rec );
> + return;
> + }
> +
> stack = virtual_setup_exception( stack_ptr, sizeof(*stack), rec );
> stack->rec = *rec;
> stack->context = context;
> @@ -834,7 +840,7 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> break;
> }
> if (handle_syscall_fault( context, &rec )) return;
> - setup_exception( context, &rec );
> + setup_exception( context, &rec, TRUE );
> }
>
>
> @@ -858,7 +864,7 @@ static void trap_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.NumberParameters = 1;
> break;
> }
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> @@ -915,7 +921,7 @@ static void fpe_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.ExceptionCode = EXCEPTION_FLT_INVALID_OPERATION;
> break;
> }
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> @@ -944,7 +950,7 @@ static void abrt_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> {
> EXCEPTION_RECORD rec = { EXCEPTION_WINE_ASSERTION, EH_NONCONTINUABLE };
>
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> diff --git a/dlls/ntdll/unix/signal_arm64.c b/dlls/ntdll/unix/signal_arm64.c
> index 680a14223c6..ef70d4df44b 100644
> --- a/dlls/ntdll/unix/signal_arm64.c
> +++ b/dlls/ntdll/unix/signal_arm64.c
> @@ -618,7 +618,7 @@ __ASM_GLOBAL_FUNC( raise_func_trampoline,
> *
> * Modify the signal context to call the exception raise function.
> */
> -static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
> +static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec, BOOL first_chance )
> {
> struct
> {
> @@ -634,13 +634,19 @@ static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
> rec->ExceptionAddress = (void *)PC_sig(sigcontext);
> save_context( &context, sigcontext );
>
> - status = send_debug_event( rec, &context, TRUE );
> + status = send_debug_event( rec, &context, first_chance );
> if (status == DBG_CONTINUE || status == DBG_EXCEPTION_HANDLED)
> {
> restore_context( &context, sigcontext );
> return;
> }
>
> + if (!first_chance)
> + {
> + handle_second_chance_exception( rec );
> + return;
> + }
> +
> stack = virtual_setup_exception( stack_ptr, (sizeof(*stack) + 15) & ~15, rec );
> stack->rec = *rec;
> stack->context = context;
> @@ -861,7 +867,7 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> (void *)SP_sig(context) );
> if (!rec.ExceptionCode) return;
> if (handle_syscall_fault( context, &rec )) return;
> - setup_exception( context, &rec );
> + setup_exception( context, &rec, TRUE );
> }
>
>
> @@ -874,7 +880,7 @@ static void ill_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> {
> EXCEPTION_RECORD rec = { EXCEPTION_ILLEGAL_INSTRUCTION };
>
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> @@ -887,7 +893,7 @@ static void bus_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> {
> EXCEPTION_RECORD rec = { EXCEPTION_DATATYPE_MISALIGNMENT };
>
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> @@ -911,7 +917,7 @@ static void trap_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.NumberParameters = 1;
> break;
> }
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> @@ -968,7 +974,7 @@ static void fpe_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.ExceptionCode = EXCEPTION_FLT_INVALID_OPERATION;
> break;
> }
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> @@ -997,7 +1003,7 @@ static void abrt_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> {
> EXCEPTION_RECORD rec = { EXCEPTION_WINE_ASSERTION, EH_NONCONTINUABLE };
>
> - setup_exception( sigcontext, &rec );
> + setup_exception( sigcontext, &rec, TRUE );
> }
>
>
> diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
> index bf3abc1a587..e18aed2c222 100644
> --- a/dlls/ntdll/unix/signal_i386.c
> +++ b/dlls/ntdll/unix/signal_i386.c
> @@ -1400,7 +1400,8 @@ static void *setup_exception_record( ucontext_t *sigcontext, EXCEPTION_RECORD *r
> * Change context to setup a call to a raise exception function.
> */
> static void setup_raise_exception( ucontext_t *sigcontext, void *stack_ptr,
> - EXCEPTION_RECORD *rec, struct xcontext *xcontext )
> + EXCEPTION_RECORD *rec, struct xcontext *xcontext,
> + BOOL first_chance )
> {
> CONTEXT *context = &xcontext->c;
> size_t stack_size;
> @@ -1420,7 +1421,7 @@ static void setup_raise_exception( ucontext_t *sigcontext, void *stack_ptr,
>
> C_ASSERT( (offsetof(struct stack_layout, xstate) == sizeof(struct stack_layout)) );
>
> - NTSTATUS status = send_debug_event( rec, context, TRUE );
> + NTSTATUS status = send_debug_event( rec, context, first_chance );
>
> if (status == DBG_CONTINUE || status == DBG_EXCEPTION_HANDLED)
> {
> @@ -1428,6 +1429,12 @@ C_ASSERT( (offsetof(struct stack_layout, xstate) == sizeof(struct stack_layout))
> return;
> }
>
> + if (!first_chance)
> + {
> + handle_second_chance_exception( rec );
> + return;
> + }
> +
> /* fix up instruction pointer in context for EXCEPTION_BREAKPOINT */
> if (rec->ExceptionCode == EXCEPTION_BREAKPOINT) context->Eip--;
>
> @@ -1482,7 +1489,7 @@ static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
> struct xcontext xcontext;
> void *stack = setup_exception_record( sigcontext, rec, &xcontext );
>
> - setup_raise_exception( sigcontext, stack, rec, &xcontext );
> + setup_raise_exception( sigcontext, stack, rec, &xcontext, TRUE );
> }
>
> /* stack layout when calling an user apc function.
> @@ -1675,7 +1682,7 @@ static BOOL handle_interrupt( unsigned int interrupt, ucontext_t *sigcontext, vo
> rec->ExceptionInformation[0] = context->Eax;
> rec->ExceptionInformation[1] = context->Ecx;
> rec->ExceptionInformation[2] = context->Edx;
> - setup_raise_exception( sigcontext, stack, rec, xcontext );
> + setup_raise_exception( sigcontext, stack, rec, xcontext, TRUE );
> return TRUE;
> default:
> return FALSE;
> @@ -1848,7 +1855,7 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> break;
> }
> if (handle_syscall_fault( ucontext, stack, &rec, &xcontext.c )) return;
> - setup_raise_exception( ucontext, stack, &rec, &xcontext );
> + setup_raise_exception( ucontext, stack, &rec, &xcontext, TRUE );
> }
>
>
> @@ -1894,7 +1901,7 @@ static void trap_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.ExceptionInformation[2] = 0; /* FIXME */
> break;
> }
> - setup_raise_exception( sigcontext, stack, &rec, &xcontext );
> + setup_raise_exception( sigcontext, stack, &rec, &xcontext, TRUE );
> }
>
>
> @@ -1939,7 +1946,7 @@ static void fpe_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.ExceptionCode = EXCEPTION_FLT_INVALID_OPERATION;
> break;
> }
> - setup_raise_exception( sigcontext, stack, &rec, &xcontext );
> + setup_raise_exception( sigcontext, stack, &rec, &xcontext, TRUE );
> }
>
>
> diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
> index 9e9a96db832..ff4a40c7933 100644
> --- a/dlls/ntdll/unix/signal_x86_64.c
> +++ b/dlls/ntdll/unix/signal_x86_64.c
> @@ -2110,7 +2110,7 @@ NTSTATUS get_thread_wow64_context( HANDLE handle, void *ctx, ULONG size )
> /***********************************************************************
> * setup_raise_exception
> */
> -static void setup_raise_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec, struct xcontext *xcontext )
> +static void setup_raise_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec, struct xcontext *xcontext, BOOL first_chance )
> {
> void *stack_ptr = (void *)(RSP_sig(sigcontext) & ~15);
> CONTEXT *context = &xcontext->c;
> @@ -2136,13 +2136,19 @@ static void setup_raise_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec
> context->EFlags &= ~0x100; /* clear single-step flag */
> }
>
> - status = send_debug_event( rec, context, TRUE );
> + status = send_debug_event( rec, context, first_chance );
> if (status == DBG_CONTINUE || status == DBG_EXCEPTION_HANDLED)
> {
> restore_context( xcontext, sigcontext );
> return;
> }
>
> + if (!first_chance)
> + {
> + handle_second_chance_exception( rec );
> + return;
> + }
> +
> /* fix up instruction pointer in context for EXCEPTION_BREAKPOINT */
> if (rec->ExceptionCode == EXCEPTION_BREAKPOINT) context->Rip--;
>
> @@ -2193,7 +2199,7 @@ static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
>
> rec->ExceptionAddress = (void *)RIP_sig(sigcontext);
> save_context( &context, sigcontext );
> - setup_raise_exception( sigcontext, rec, &context );
> + setup_raise_exception( sigcontext, rec, &context, TRUE );
> }
>
>
> @@ -2461,7 +2467,7 @@ static inline BOOL handle_interrupt( ucontext_t *sigcontext, EXCEPTION_RECORD *r
> default:
> return FALSE;
> }
> - setup_raise_exception( sigcontext, rec, xcontext );
> + setup_raise_exception( sigcontext, rec, xcontext, TRUE );
> return TRUE;
> }
>
> @@ -2614,7 +2620,7 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> break;
> }
> if (handle_syscall_fault( sigcontext, &rec, &context.c )) return;
> - setup_raise_exception( sigcontext, &rec, &context );
> + setup_raise_exception( sigcontext, &rec, &context, TRUE );
> }
>
>
> @@ -2658,7 +2664,7 @@ static void trap_handler( int signal, siginfo_t *siginfo, void *sigcontext )
> rec.ExceptionInformation[0] = 0;
> break;
> }
> - setup_raise_exception( sigcontext, &rec, &context );
> + setup_raise_exception( sigcontext, &rec, &context, TRUE );
> }
>
>
> diff --git a/dlls/ntdll/unix/thread.c b/dlls/ntdll/unix/thread.c
> index 455272e07e0..d7204b2fd3b 100644
> --- a/dlls/ntdll/unix/thread.c
> +++ b/dlls/ntdll/unix/thread.c
> @@ -87,6 +87,24 @@ static inline int get_unix_exit_code( NTSTATUS status )
> }
>
>
> +/***********************************************************************
> + * handle_second_chance_exception
> + *
> + * Handle a second chance exception.
> + */
> +void handle_second_chance_exception( EXCEPTION_RECORD *rec )
> +{
> + if (rec->ExceptionFlags & EH_STACK_INVALID)
> + ERR_(seh)("Exception frame is not in stack limits => unable to dispatch exception.\n");
> + else if (rec->ExceptionCode == STATUS_NONCONTINUABLE_EXCEPTION)
> + ERR_(seh)("Process attempted to continue execution after noncontinuable exception.\n");
> + else
> + ERR_(seh)("Unhandled exception code %x flags %x addr %p\n",
> + rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress );
> +
> + NtTerminateProcess( NtCurrentProcess(), rec->ExceptionCode );
> +}
> +
> /***********************************************************************
> * fpux_to_fpu
> *
> @@ -1509,15 +1527,7 @@ NTSTATUS WINAPI NtRaiseException( EXCEPTION_RECORD *rec, CONTEXT *context, BOOL
>
> if (first_chance) return call_user_exception_dispatcher( rec, context );
>
> - if (rec->ExceptionFlags & EH_STACK_INVALID)
> - ERR_(seh)("Exception frame is not in stack limits => unable to dispatch exception.\n");
> - else if (rec->ExceptionCode == STATUS_NONCONTINUABLE_EXCEPTION)
> - ERR_(seh)("Process attempted to continue execution after noncontinuable exception.\n");
> - else
> - ERR_(seh)("Unhandled exception code %x flags %x addr %p\n",
> - rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress );
> -
> - NtTerminateProcess( NtCurrentProcess(), rec->ExceptionCode );
> + handle_second_chance_exception( rec );
> return STATUS_SUCCESS;
> }
>
> diff --git a/dlls/ntdll/unix/unix_private.h b/dlls/ntdll/unix/unix_private.h
> index 0dcb09ad641..d5414474d2e 100644
> --- a/dlls/ntdll/unix/unix_private.h
> +++ b/dlls/ntdll/unix/unix_private.h
> @@ -172,6 +172,7 @@ extern void server_init_process_done(void) DECLSPEC_HIDDEN;
> extern void server_init_thread( void *entry_point, BOOL *suspend ) DECLSPEC_HIDDEN;
> extern int server_pipe( int fd[2] ) DECLSPEC_HIDDEN;
>
> +void handle_second_chance_exception( EXCEPTION_RECORD *rec );
> extern void fpux_to_fpu( I386_FLOATING_SAVE_AREA *fpu, const XSAVE_FORMAT *fpux ) DECLSPEC_HIDDEN;
> extern void fpu_to_fpux( XSAVE_FORMAT *fpux, const I386_FLOATING_SAVE_AREA *fpu ) DECLSPEC_HIDDEN;
> extern void *get_cpu_area( USHORT machine ) DECLSPEC_HIDDEN;
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