And discard irrelevant parts in select request. We currently store something in CTX_PENDING and ignore it later in select request if we're currently running in wow context.
-- v2: ntdll/tests: Add tests for setting context on unsuspended thread. server: Store both contexts in pending context object.
From: Jacek Caban jacek@codeweavers.com
And discard irrelevant parts in select request. --- server/thread.c | 67 +++++++++++++++++++++++++------------------------ 1 file changed, 34 insertions(+), 33 deletions(-)
diff --git a/server/thread.c b/server/thread.c index 3e35b27f694..e9c6ef4e463 100644 --- a/server/thread.c +++ b/server/thread.c @@ -119,11 +119,10 @@ struct context { struct object obj; /* object header */ unsigned int status; /* status of the context */ - context_t regs[3]; /* context data */ + context_t regs[2]; /* context data */ }; #define CTX_NATIVE 0 /* context for native machine */ #define CTX_WOW 1 /* context if thread is inside WoW */ -#define CTX_PENDING 2 /* pending native context when we don't know whether thread is inside WoW */
/* flags for registers that always need to be set from the server side */ static const unsigned int system_flags = SERVER_CTX_DEBUG_REGISTERS; @@ -292,7 +291,6 @@ static struct context *create_thread_context( struct thread *thread ) context->status = STATUS_PENDING; memset( &context->regs, 0, sizeof(context->regs) ); context->regs[CTX_NATIVE].machine = native_machine; - context->regs[CTX_PENDING].machine = native_machine; return context; }
@@ -1605,7 +1603,14 @@ DECL_HANDLER(select) } else goto invalid_param;
- if (!current->context && !(current->context = create_thread_context( current ))) return; + if ((ctx = current->context)) + { + if (ctx->status != STATUS_PENDING) goto invalid_param; + /* if context was modified in pending state, discard irrelevant changes */ + if (wow_context) ctx->regs[CTX_NATIVE].flags &= ~ctx->regs[CTX_WOW].flags; + else ctx->regs[CTX_WOW].flags = ctx->regs[CTX_WOW].machine = 0; + } + else if (!(current->context = create_thread_context( current ))) return;
ctx = current->context; if (native_context) @@ -1618,13 +1623,6 @@ DECL_HANDLER(select) ctx->regs[CTX_WOW].machine = current->process->machine; copy_context( &ctx->regs[CTX_WOW], wow_context, wow_context->flags & ~ctx->regs[CTX_WOW].flags ); } - else if (ctx->regs[CTX_PENDING].flags) - { - unsigned int flags = ctx->regs[CTX_PENDING].flags & ~ctx->regs[CTX_NATIVE].flags; - copy_context( &ctx->regs[CTX_NATIVE], &ctx->regs[CTX_PENDING], flags ); - ctx->regs[CTX_NATIVE].flags |= flags; - } - ctx->regs[CTX_PENDING].flags = 0; ctx->status = STATUS_SUCCESS; current->suspend_cookie = req->cookie; wake_up( &ctx->obj, 0 ); @@ -1931,36 +1929,39 @@ DECL_HANDLER(set_thread_context) set_error( STATUS_INVALID_PARAMETER ); else if (thread->state != TERMINATED) { - unsigned int ctx = CTX_NATIVE; - const context_t *context = &contexts[CTX_NATIVE]; - unsigned int flags = system_flags & context->flags; - unsigned int native_flags = context->flags & req->native_flags; + unsigned int flags = system_flags & contexts[CTX_NATIVE].flags;
if (thread != current) stop_thread( thread ); - else if (flags) set_thread_context( thread, context, flags ); + else if (contexts[CTX_NATIVE].flags) set_thread_context( thread, &contexts[CTX_NATIVE], flags ); + if (thread->context && !get_error()) { - if (ctx_count == 2) + /* If context is in a pending state, we don't know if we will use WoW or native + * context, so store both and discard irrevelant one in select request. */ + const int is_pending = thread->context->status == STATUS_PENDING; + unsigned int native_flags = contexts[CTX_NATIVE].flags & req->native_flags; + + if (native_flags) /* some regs are always set from the native context */ { - /* If the target thread doesn't have a WoW context, set native instead. - * If we don't know yet whether we have a WoW context, store native context - * in CTX_PENDING and update when the target thread sends its context(s). */ - if (thread->context->status != STATUS_PENDING) - { - ctx = thread->context->regs[CTX_WOW].machine ? CTX_WOW : CTX_NATIVE; - context = &contexts[ctx]; - } - else ctx = CTX_PENDING; + context_t *ctx = &thread->context->regs[CTX_NATIVE]; + copy_context( ctx, &contexts[CTX_NATIVE], native_flags ); + ctx->flags |= native_flags; + } + if (is_pending || !thread->context->regs[CTX_WOW].machine) + { + context_t *ctx = &thread->context->regs[CTX_NATIVE]; + flags = contexts[CTX_NATIVE].flags & ~native_flags; + copy_context( ctx, &contexts[CTX_NATIVE], flags ); + ctx->flags |= flags; } - flags = context->flags; - if (native_flags && ctx != CTX_NATIVE) /* some regs are always set from the native context */ + if (is_pending || (ctx_count == 2 && thread->context->regs[CTX_WOW].machine)) { - copy_context( &thread->context->regs[CTX_NATIVE], &contexts[CTX_NATIVE], native_flags ); - thread->context->regs[CTX_NATIVE].flags |= native_flags; - flags &= ~native_flags; + context_t *ctx = &thread->context->regs[CTX_WOW]; + flags = contexts[CTX_WOW].flags & ~native_flags; + ctx->machine = contexts[CTX_WOW].machine; + copy_context( &thread->context->regs[CTX_WOW], &contexts[CTX_WOW], flags ); + ctx->flags |= flags; } - copy_context( &thread->context->regs[ctx], context, flags ); - thread->context->regs[ctx].flags |= flags; } } else set_error( STATUS_UNSUCCESSFUL );
From: Jacek Caban jacek@codeweavers.com
Based on patch by Evan Tang. --- dlls/ntdll/tests/thread.c | 85 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+)
diff --git a/dlls/ntdll/tests/thread.c b/dlls/ntdll/tests/thread.c index 56fb078babc..1ec2410409a 100644 --- a/dlls/ntdll/tests/thread.c +++ b/dlls/ntdll/tests/thread.c @@ -197,6 +197,90 @@ static void test_errno(void) ok( val == 0xbeef, "wrong value %x\n", val ); }
+#if defined(__i386__) +# define IP_REG(ctx) ctx.Eip +#elif defined(__x86_64__) +# define IP_REG(ctx) ctx.Rip +#endif + +#ifdef IP_REG +static volatile int exit_ip_test; +static WINAPI DWORD ip_test_thread_proc( void *param ) +{ + SetEvent( param ); + while (!exit_ip_test); + return ERROR_SUCCESS; +} +#endif + +static void test_set_thread_context_ip(void) +{ +#ifdef IP_REG + UINT_PTR old_ip, target; + HANDLE thread, event; + char *target_ptr; + CONTEXT ctx; + DWORD res; + int i; + + /* jmp to self at offset 0 and 4 */ + static const char target_code[] = {0xeb, 0xfe, 0x90, 0x90, 0xeb, 0xfe}; + + target_ptr = VirtualAlloc( NULL, 65536, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE ); + memcpy( target_ptr, target_code, sizeof(target_code) ); + target = (UINT_PTR)target_ptr; + + event = CreateEventW( NULL, TRUE, FALSE, NULL ); + thread = CreateThread( NULL, 65536, ip_test_thread_proc, event, 0, NULL ); + ok( thread != NULL, "Failed to create thread: %lx\n", GetLastError() ); + res = WaitForSingleObject( event, 1000 ); + ok( !res, "wait returned: %ld\n", res ); + CloseHandle( event ); + + memset( &ctx, 0, sizeof(ctx) ); + ctx.ContextFlags = CONTEXT_ALL; + res = GetThreadContext( thread, &ctx ); + ok( res, "Failed to get thread context: %lx\n", GetLastError() ); + old_ip = IP_REG(ctx); + + IP_REG(ctx) = target; + res = SetThreadContext( thread, &ctx ); + ok( res, "Failed to set thread context: %lx\n", GetLastError() ); + + for (i = 0; i < 10; i++) + { + IP_REG(ctx) = target; + res = SetThreadContext( thread, &ctx ); + ok( res, "Failed to set thread context: %lx\n", GetLastError() ); + + ctx.ContextFlags = CONTEXT_ALL; + res = GetThreadContext( thread, &ctx ); + ok( res, "Failed to get thread context: %lx\n", GetLastError() ); + ok( IP_REG(ctx) == target, "IP = %p, expected %p\n", (void *)IP_REG(ctx), target_ptr ); + + IP_REG(ctx) = target + 4; + res = SetThreadContext( thread, &ctx ); + ok( res, "Failed to set thread context: %lx\n", GetLastError()) ; + + ctx.ContextFlags = CONTEXT_ALL; + res = GetThreadContext( thread, &ctx ); + ok( res, "Failed to get thread context: %lx\n", GetLastError() ); + ok( IP_REG(ctx) == target + 4, "IP = %p, expected %p\n", (void *)IP_REG(ctx), target_ptr + 4 ); + } + + exit_ip_test = 1; + ctx.ContextFlags = CONTEXT_ALL; + IP_REG(ctx) = old_ip; + res = SetThreadContext( thread, &ctx ); + ok( res, "Failed to restore thread context: %lx\n", GetLastError() ); + + res = WaitForSingleObject( thread, 1000 ); + ok( !res, "wait returned: %ld\n", res ); + + VirtualFree( target_ptr, 0, MEM_RELEASE ); +#endif +} + START_TEST(thread) { init_function_pointers(); @@ -204,4 +288,5 @@ START_TEST(thread) test_dbg_hidden_thread_creation(); test_unique_teb(); test_errno(); + test_set_thread_context_ip(); }
AFAIK there is a bug (probably https://bugs.winehq.org//show_bug.cgi?id=55092) in the current implementation where the wow64 context does not alias the native context when the process is in emulation (wow64) mode. I attempted to fix this in https://gitlab.winehq.org/wine/wine/-/merge_requests/123, but it causes conflicts with this MR. I've not looked into this MR in details, but I was wondering if the bug has been taken into consideration.
On Tue Aug 15 17:16:05 2023 +0000, Jinoh Kang wrote:
AFAIK there is a bug (probably https://bugs.winehq.org//show_bug.cgi?id=55092) in the current implementation where the wow64 context does not alias the native context when the process is in emulation (wow64) mode. I attempted to fix this in https://gitlab.winehq.org/wine/wine/-/merge_requests/123, but it causes conflicts with this MR. I've not looked into this MR in details, but I was wondering if the bug has been taken into consideration.
Your MR seems relevant. I think that part of it was addressed by 5031c6d938f119580e. It will still not work if target thread is not fully suspended (not suspended at all, like in attached tests, or suspend request issued a signal, but did not yet receive a select request) and that's what I'm trying to fix.
I'm not sure if mentioned bug is related.
Jinoh Kang (@iamahuman) commented about server/thread.c:
set_error( STATUS_INVALID_PARAMETER ); else if (thread->state != TERMINATED) {
unsigned int ctx = CTX_NATIVE;const context_t *context = &contexts[CTX_NATIVE];unsigned int flags = system_flags & context->flags;unsigned int native_flags = context->flags & req->native_flags;
unsigned int flags = system_flags & contexts[CTX_NATIVE].flags; if (thread != current) stop_thread( thread );
else if (flags) set_thread_context( thread, context, flags );
else if (contexts[CTX_NATIVE].flags) set_thread_context( thread, &contexts[CTX_NATIVE], flags );
```suggestion:-0+0 else if (flags) set_thread_context( thread, &contexts[CTX_NATIVE], flags ); ```
If `contexts[CTX_NATIVE].flags` was nonzero but `SERVER_CTX_DEBUG_REGISTERS` was unset, this will lead to an assertion failure. Guaranteed, such case doesn't happen in tests; however, consistenly using `flags` looks more readable.
-
Jacek Caban -
Jacek Caban (＠jacek)
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Jinoh Kang (＠iamahuman)