mgdb: winnt_exception_filters[]: initial implementation and integration.

2 files changed, 134 insertions, 2 deletions

diff --git a/overlay/mgdb/gdb/winnt-nat.c b/overlay/mgdb/gdb/winnt-nat.c
index 7c456d6..4a27c40 100644
--- a/overlay/mgdb/gdb/winnt-nat.c
+++ b/overlay/mgdb/gdb/winnt-nat.c
@@ -38,11 +38,19 @@
 #define winnt_perror(msg,pid) \
 	error("%s(): %s (pid %d).",__FUNCTION__,msg,pid)
 
+#define WINNT_W32_EXCEPTION_MASK ((0xe << 28) | ('m' << 16) | ('s' << 8) | ('c' << 0))
+
 static size_t          pcnt;
 static winnt_process * plist;
 static char *          outbuf;
 static struct pe_driver_ctx * pe_dctx;
 
+static struct winnt_exception_filter winnt_exception_filters[] = {
+	{WINNT_W32_EXCEPTION_MASK,  WINNT_EXCEPTION_FIRST_CHANCE,   0},
+	{0,                         WINNT_EXCEPTION_FIRST_CHANCE,   "sysfer.dll"},
+	{0,                         0,                              0},
+};
+
 static winnt_process * winnt_plist_expand (void)
 {
 	struct winnt_process * pnew;
@@ -775,6 +783,104 @@ static void winnt_detach (struct target_ops * t, const char * args, int from_tty
 	exec_file_clear(from_tty);
 }
 
+static int winnt_exception_filter_match_code(
+	struct __dbg_event *		event,
+	struct winnt_exception_filter *	filter)
+{
+	if (!filter->exception_code)
+		return 1;
+
+	if (!event->exception_record)
+		return 0;
+
+	if (filter->exception_code != event->exception_record->exception_code)
+		return 0;
+
+	if (filter->exception_flags & WINNT_EXCEPTION_FIRST_CHANCE)
+		if (event->exception_priority)
+			return 1;
+
+	if (filter->exception_flags & WINNT_EXCEPTION_SECOND_CHANCE)
+		if (!event->exception_priority)
+			return 1;
+
+	return 0;
+}
+
+static int winnt_exception_filter_match_module(
+	struct __dbg_event *		event,
+	struct winnt_exception_filter *	filter,
+	struct winnt_process*		pidinfo)
+{
+	struct __dbg_module_info *	module;
+	struct __dbg_module_info *	module_cap;
+	struct winnt_thread *		thread;
+	struct pe_unit_ctx *		uctx;
+	struct pe_meta_sec_hdr *	sechdr;
+	int				secidx;
+	char *				addr;
+	char *				mark;
+	char *				text;
+	char *				text_cap;
+
+	thread     = winnt_get_thread(pidinfo,event->systid);
+	addr       = (char *)thread->regctx.uc_rip;
+	module_cap = &pidinfo->modules[pidinfo->nmodules];
+
+	for (module=pidinfo->modules; module<module_cap; module++) {
+		if ((uctx = (struct pe_unit_ctx *)module->module_ctx)) {
+			secidx = pe_get_named_section_index(
+				uctx->meta,".text");
+
+			if (secidx >= 0) {
+				mark      = 0;
+				sechdr    = &uctx->meta->m_sectbl[secidx];
+				text      = (char *)module->module_base;
+				text     += sechdr->sh_virtual_addr;
+				text_cap  = text + sechdr->sh_virtual_size;
+
+				if ((addr >= text) && (addr < text_cap))
+					mark = strrchr(module->module_name,'/');
+
+				if (mark && !filter->exception_module)
+					return 1;
+
+				if (mark && filter->exception_module)
+					if (!(strcmp(++mark,filter->exception_module)))
+						return 1;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int winnt_exception_filter_match(struct __dbg_event * event)
+{
+	struct winnt_process *          pidinfo;
+	struct winnt_exception_filter * filter = winnt_exception_filters;
+
+	switch (event->evttype) {
+		case __DBG_STATE_EXCEPTION:
+		case __DBG_STATE_BREAKPOINT:
+		case __DBG_STATE_SINGLE_STEP:
+			break;
+
+		default:
+			return 0;
+	}
+
+	if (!(pidinfo = winnt_process_record(event->syspid)))
+		return 0;
+
+	for (; filter->exception_flags; filter++)
+		if (winnt_exception_filter_match_code(event,filter))
+			if (winnt_exception_filter_match_module(event,filter,pidinfo))
+				return 1;
+
+	return 0;
+}
+
 static struct __dbg_event * winnt_wait_event(ptid_t ptid)
 {
 	struct __dbg_event	event;
@@ -850,11 +956,27 @@ static ptid_t winnt_wait(
 	int                    pfd;
 	struct __dbg_event *   event;
 	struct winnt_process * process;
+	int                    fskip;
+	int                    eresponse;
 
 	target_terminal_ours();
 
-	if (!(event = winnt_wait_event(ptid)))
-		return null_ptid;
+	do {
+		if (!(event = winnt_wait_event(ptid)))
+			return null_ptid;
+
+		if ((fskip = winnt_exception_filter_match(event))) {
+			if (!(process = winnt_process_record(event->syspid)))
+				return null_ptid;
+
+			if (event->exception_priority)
+				eresponse = __DBG_RESPONSE_EXCEPTION_NOT_HANDLED;
+			else
+				eresponse = __DBG_RESPONSE_CONTINUE;
+
+			winnt_respond(process->pfd,event,eresponse);
+		}
+	} while (fskip);
 
 	if (!(process = winnt_process_record(event->syspid)))
 		return null_ptid;
diff --git a/overlay/mgdb/gdb/winnt-nat.h b/overlay/mgdb/gdb/winnt-nat.h
index 473c2a9..593a140 100644
--- a/overlay/mgdb/gdb/winnt-nat.h
+++ b/overlay/mgdb/gdb/winnt-nat.h
@@ -18,6 +18,10 @@
 #define WINNT_THREAD_CONTEXT_READY	(0X0)
 #define WINNT_THREAD_CONTEXT_DIRTY	(0Xffffffff)
 
+#define WINNT_EXCEPTION_FIRST_CHANCE	0x01
+#define WINNT_EXCEPTION_SECOND_CHANCE	0x02
+#define WINNT_EXCEPTION_ALL		0xffffffff
+
 struct regcache;
 
 struct winnt_process;
@@ -46,6 +50,12 @@ struct winnt_thread {
 	mcontext_t			regctx;
 };
 
+struct winnt_exception_filter {
+	uint32_t			exception_code;
+	uint32_t			exception_flags;
+	const char *			exception_module;
+};
+
 void amd64_winnt_fetch_registers(
 	struct regcache *, int regnum,
 	struct winnt_thread *);