+2008-02-27 Christopher Faylor <me+cygwin@cgf.cx>
+
+ * cygtls.cc (_cygtls::handle_threadlist_exception): Make it clear that
+ the function never actually returns.
+ * exceptions.cc (_cygtls::handle_exceptions): Jump out of function
+ rather than returning to avoid meddling by previously installed
+ exception handlers.
+
2008-02-25 Corinna Vinschen <corinna@vinschen.de>
* dcrt0.cc (initial_env): Only use local buffer "buf" if DEBUGGING is
infodata = pack->si;
}
-extern "C" DWORD __stdcall RtlUnwind (void *, void *, void *, DWORD);
+extern "C" DWORD __stdcall RtlUnwind (void *, void *, void *, DWORD) __attribute__ ((noreturn));
int
_cygtls::handle_threadlist_exception (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *c, void *)
{
cygheap->threadlist[threadlist_ix]->remove (INFINITE);
threadlist_ix = 0;
RtlUnwind (frame, threadlist_exception_return, e, 0);
- return 0;
+ /* Never returns */
}
/* Set up the exception handler for the current thread. The x86 uses segment
sig_send (NULL, si, &me); // Signal myself
me.incyg--;
e->ExceptionFlags = 0;
- return 0;
+ /* The OS adds an exception list frame to the stack. It expects to be
+ able to remove this entry after the exception handler returned.
+ However, when unwinding to our frame, our frame becomes the uppermost
+ frame on the stack (%fs:0 points to frame). This way, our frame
+ is removed from the exception stack and just disappears. So, we can't
+ just return here or things will be screwed up by the helpful function
+ in (presumably) ntdll.dll.
+
+ So, instead, we will do the equivalent of a longjmp here and return
+ to the caller without visiting any of the helpful code installed prior
+ to this function. This should work ok, since a longjmp() out of here has
+ to work if linux signal semantics are to be maintained. */
+
+ SetThreadContext (GetCurrentThread (), in);
+ return 0; /* Never actually returns. This is just to keep gcc happy. */
}
/* Utilities to call a user supplied exception handler. */