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Ping (Re: Patch : gdbserver get_image_name on CE)
- From: Danny Backx <danny dot backx at scarlet dot be>
- To: gdb-patches <gdb-patches at sourceware dot org>
- Date: Tue, 11 Aug 2009 22:05:02 +0200
- Subject: Ping (Re: Patch : gdbserver get_image_name on CE)
- Reply-to: danny dot backx at scarlet dot be
Ping again.
On Mon, 2009-07-27, Danny Backx wrote:
> Ping ?
>
> On Wed, 2009-07-08 at 13:33 +0200, Danny Backx wrote:
> > On Wed, 2009-07-08 at 11:55 +0200, Danny Backx wrote:
> > > It looks like ReadProcessMemory refuses to read from an address
> beyond
> > > the pointer, but it does work from the pointer itself.
> > >
> > > I've changed my code such that it loops, and tries to read a
> bigger
> > > chunk of memory at each iteration.
> > >
> > > I'm not bothering you with that code or its debug output right
> now.
> > >
> > > In that way, the code appears to work, and it complies with the
> > > documentation saying not to read more than required.
> > >
> > > Shall I submit a new patch based on this ?
> > >
> > > Danny
> >
> > Ignore that question, here's the patch.
> >
> > Please comment on its contents and on my adherence to the coding
> > standards. Apologies for that, I seem to have a hard time learning
> that.
> >
> > Danny
> >
> > 2009-07-08 Danny Backx <dannybackx@users.sourceforge.net>
> >
> > * win32-low.c (get_image_name) : Work around ReadProcessMemory
> > failure when reading at arbitrary addresses.
--
Danny Backx ; danny.backx - at - scarlet.be ; http://danny.backx.info
Index: win32-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-low.c,v
retrieving revision 1.38
diff -u -r1.38 win32-low.c
--- win32-low.c 4 Jul 2009 18:13:28 -0000 1.38
+++ win32-low.c 11 Aug 2009 20:01:19 -0000
@@ -922,7 +922,6 @@
DWORD size = unicode ? sizeof (WCHAR) : sizeof (char);
char *address_ptr;
int len = 0;
- char b[2];
DWORD done;
/* Attempt to read the name of the dll that was detected.
@@ -945,21 +944,23 @@
return NULL;
#endif
- /* Find the length of the string */
- while (ReadProcessMemory (h, address_ptr + len++ * size, &b, size, &done)
- && (b[0] != 0 || b[size - 1] != 0) && done == size)
- continue;
+ /* ReadProcessMemory sometimes fails when reading a (w)char at a time, but
+ * we can't just read MAX_PATH (w)chars either : msdn says not to cross the
+ * boundary into inaccessible areas.
+ * So we loop, reading more characters each time, until we find the NULL.
+ */
+ WCHAR *wbuf = alloca ((MAX_PATH + 1) * size);
+ while (1)
+ {
+ ReadProcessMemory (h, address_ptr, wbuf, ++len * size, &done);
+ if (wbuf[len - 1] == 0)
+ break;
+ }
if (!unicode)
ReadProcessMemory (h, address_ptr, buf, len, &done);
else
- {
- WCHAR *unicode_address = (WCHAR *) alloca (len * sizeof (WCHAR));
- ReadProcessMemory (h, address_ptr, unicode_address, len * sizeof (WCHAR),
- &done);
-
- WideCharToMultiByte (CP_ACP, 0, unicode_address, len, buf, len, 0, 0);
- }
+ WideCharToMultiByte (CP_ACP, 0, wbuf, len, buf, len, 0, 0);
return buf;
}