On Fri, Dec 17, 2021 at 02:53:05PM +0000, Alex Bennée wrote: > > Daniel P. Berrangé <berra...@redhat.com> writes: > > > On Thu, Dec 16, 2021 at 02:11:37PM +0000, Alex Bennée wrote: > >> > >> Philippe Mathieu-Daudé <phi...@redhat.com> writes: > >> > >> > When experimenting raising GLIB_VERSION_MIN_REQUIRED to 2.68 > >> > (Fedora 34 provides GLib 2.68.1) we get: > >> > > >> > hw/virtio/virtio-crypto.c:245:24: error: 'g_memdup' is deprecated: Use > >> > 'g_memdup2' instead [-Werror,-Wdeprecated-declarations] > >> > ... > >> > > >> > g_memdup() has been updated by g_memdup2() to fix eventual security > >> > issues (size argument is 32-bit and could be truncated / wrapping). > >> > GLib recommends to copy their static inline version of g_memdup2(): > >> > https://discourse.gnome.org/t/port-your-module-from-g-memdup-to-g-memdup2-now/5538 > >> > > >> > Our glib-compat.h provides a comment explaining how to deal with > >> > these deprecated declarations (see commit e71e8cc0355 > >> > "glib: enforce the minimum required version and warn about old APIs"). > >> > > >> > Following this comment suggestion, implement the g_memdup2_qemu() > >> > wrapper to g_memdup2(), and use the safer equivalent inlined when > >> > we are using pre-2.68 GLib. > >> > > >> > Reported-by: Eric Blake <ebl...@redhat.com> > >> > Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com> > >> > --- > >> > include/glib-compat.h | 37 +++++++++++++++++++++++++++++++++++++ > >> > 1 file changed, 37 insertions(+) > >> > > >> > diff --git a/include/glib-compat.h b/include/glib-compat.h > >> > index 9e95c888f54..8d01a8c01fb 100644 > >> > --- a/include/glib-compat.h > >> > +++ b/include/glib-compat.h > >> > @@ -68,6 +68,43 @@ > >> > * without generating warnings. > >> > */ > >> > > >> > +/* > >> > + * g_memdup2_qemu: > >> > + * @mem: (nullable): the memory to copy. > >> > + * @byte_size: the number of bytes to copy. > >> > + * > >> > + * Allocates @byte_size bytes of memory, and copies @byte_size bytes > >> > into it > >> > + * from @mem. If @mem is %NULL it returns %NULL. > >> > + * > >> > + * This replaces g_memdup(), which was prone to integer overflows when > >> > + * converting the argument from a #gsize to a #guint. > >> > + * > >> > + * This static inline version is a backport of the new public API from > >> > + * GLib 2.68, kept internal to GLib for backport to older stable > >> > releases. > >> > + * See https://gitlab.gnome.org/GNOME/glib/-/issues/2319. > >> > + * > >> > + * Returns: (nullable): a pointer to the newly-allocated copy of the > >> > memory, > >> > + * or %NULL if @mem is %NULL. > >> > + */ > >> > +static inline gpointer g_memdup2_qemu(gconstpointer mem, gsize > >> > byte_size) > >> > +{ > >> > +#if GLIB_CHECK_VERSION(2, 68, 0) > >> > + return g_memdup2(mem, byte_size); > >> > +#else > >> > + gpointer new_mem; > >> > + > >> > + if (mem && byte_size != 0) { > >> > + new_mem = g_malloc(byte_size); > >> > + memcpy(new_mem, mem, byte_size); > >> > + } else { > >> > + new_mem = NULL; > >> > + } > >> > + > >> > + return new_mem; > >> > +#endif > >> > +} > >> > +#define g_memdup2(m, s) g_memdup2_qemu(m, s) > >> > + > >> > >> As per our style wouldn't it make sense to just call it qemu_memdup(m, > >> s)? > > > > Not in this case. We use suffix as we don't want people calling this > > directly with the suffix. > > > > In the glibcompat.h header we're attempting to transparently/secretly > > replace/wrap standard glib APIs. All the callers should remain using > > the plain glib API name, never call the method with the suffix at > > all. This lets us delete the wrapper later and not have to update > > any callers. The suffix is basically just a hack of the impl we use > > for transparent replacement. > > Right - at the risk of bike shedding names maybe we should choose a > suffix the better reflects the purpose like _alt or _internal rather > than overloading qemu?
Sure, I'm fine with that. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|