9:02 a.m.
On Mo, 2011-12-19 at 16:47 +0100, Chris Kühl wrote:
On Mon, Dec 19, 2011 at 12:08 PM, Patrick Ohly
<patrick.ohly(a)intel.com> wrote:
> So perhaps the parameter for that can be removed and made a static
> choice in the dbus_get_bus_connection() implementations?
>
I'm about half way through test-dbus.py and things are looking fine
using the singleton connection acquired by g_bus_get_sync(). so, if my
interpretation of what you're saying is correct, we can just remove
the unshared (btw, using a negative for a boolean value is confusing.)
option and make the gio gdbus always be a shared, singleton connection
and the libdbus connection always be private. Correct?
Right.
> So let me be more precise: a "syncevolution --version"
invocation
> segfaults.
>
Hmm. I get SyncEvolution 1.2.1+20111218+SE+3f4f71a (pre-release) when
running that on my Debian Testing install. But we have had different
results in the past on Deban Testing so I'm becoming less and less
surprised by this.
Well, Testing is a moving target ;-) We might also be compiling
differently, or there is a 32/64 bit difference (I'm using 64 bit).
Anyway, as I am to reproduce it, finding the root cause wasn't that
difficult:
commit b7b17159d9e89c0452e3df99a35668a468e347d7
Author: Patrick Ohly <patrick.ohly(a)intel.com>
Date: Mon Dec 19 17:57:20 2011 +0100
GIO GDBus: fixed memory corruption
g_variant_get() does not work for C++ bool directly because at least
on x86_64, C++ bool uses 1 byte while gboolean uses 4. This caused
random stack corruption when unpacking four bytes into an address
which only had room for one. Caused "syncevolution --version" to segfault
when using a corrupted std::string later.
diff --git a/src/gdbusxx/gdbus-cxx-bridge.h b/src/gdbusxx/gdbus-cxx-bridge.h
index 106b216..568642b 100644
--- a/src/gdbusxx/gdbus-cxx-bridge.h
+++ b/src/gdbusxx/gdbus-cxx-bridge.h
@@ -1170,12 +1170,37 @@ template<> struct dbus_traits<uint32_t> :
static std::string getReply() { return ""; }
};
-template<> struct dbus_traits<bool> :
- public basic_marshal< bool, VariantTypeBoolean >
+template<> struct dbus_traits<bool>
+// cannot use basic_marshal because VariantTypeBoolean packs/unpacks
+// a gboolean, which is not a C++ bool (4 bytes vs 1 on x86_64)
+// public basic_marshal< bool, VariantTypeBoolean >
{
static std::string getType() { return "b"; }
static std::string getSignature() {return getType(); }
static std::string getReply() { return ""; }
+
+ typedef bool host_type;
+ typedef bool arg_type;
+
+ static void get(GDBusConnection *conn, GDBusMessage *msg,
+ GVariantIter &iter, bool &value)
+ {
+ GVariant *var = g_variant_iter_next_value(&iter);
+ if (var == NULL || !g_variant_type_equal(g_variant_get_type(var),
VariantTypeBoolean::getVariantType())) {
+ throw std::runtime_error("invalid argument");
+ }
+ gboolean buffer;
+ g_variant_get(var, g_variant_get_type_string(var), &buffer);
+ value = buffer;
+ g_variant_unref(var);
+ }
+
+ static void append(GVariantBuilder &builder, bool value)
+ {
+ const gchar *typeStr =
g_variant_type_dup_string(VariantTypeBoolean::getVariantType());
+ g_variant_builder_add(&builder, typeStr, (gboolean)value);
+ g_free((gpointer)typeStr);
+ }
};
--
Best Regards, Patrick Ohly
The content of this message is my personal opinion only and although
I am an employee of Intel, the statements I make here in no way
represent Intel's position on the issue, nor am I authorized to speak
on behalf of Intel on this matter.