From: Michal Privoznik <mprivozn@redhat.com>
The main difference is that wmem_packet_scope() is gone [1] but
the packet_info struct has 'pool` member which points to the
allocator used for given packet.
Unfortunately, while we were given pointer to packet_info at the
entry level to our dissector (dissect_libvirt() ->
tcp_dissect_pdus() -> dissect_libvirt_message()) it was never
propagated to generated/primitive dissectors.
But not all dissectors need to allocate memory, so mark the new
argument as unused. And while our generator could be rewritten so
that the argument is annotated as unused iff it's really unused,
I couldn't bother rewriting it. It's generated code after all.
Too much work for little gain.
Another significant change is that val_to_str() now requires new
argument: pointer to allocator to use because it always allocates
new memory [2][3].
1: https://gitlab.com/wireshark/wireshark/-/commit/5ca5c9ca372e06881b23ba9f4fdcb6b479886444
2: https://gitlab.com/wireshark/wireshark/-/commit/b63599762468e4cf1783419a5556377604d344bb
3: https://gitlab.com/wireshark/wireshark/-/commit/84799be215313e61b83a3eaf074f89d6ee349b8c
Resolves: https://gitlab.com/libvirt/libvirt/-/issues/823
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
tools/wireshark/src/packet-libvirt.c | 157 +++++++++++++++++++--------
tools/wireshark/util/genxdrstub.pl | 18 +--
2 files changed, 119 insertions(+), 56 deletions(-)
diff --git a/tools/wireshark/src/packet-libvirt.c b/tools/wireshark/src/packet-libvirt.c
index 3178ac6f27..c5c8fb4756 100644
--- a/tools/wireshark/src/packet-libvirt.c
+++ b/tools/wireshark/src/packet-libvirt.c
@@ -63,7 +63,7 @@ static gint ett_libvirt_stream_hole = -1;
#define XDR_PRIMITIVE_DISSECTOR(xtype, ctype, ftype) \
static gboolean \
- dissect_xdr_##xtype(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf) \
+ dissect_xdr_##xtype(tvbuff_t *tvb, packet_info *pinfo G_GNUC_UNUSED, proto_tree *tree, XDR *xdrs, int hf) \
{ \
goffset start; \
ctype val; \
@@ -93,7 +93,7 @@ XDR_PRIMITIVE_DISSECTOR(bool, bool_t, boolean)
VIR_WARNINGS_RESET
-typedef gboolean (*vir_xdr_dissector_t)(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf);
+typedef gboolean (*vir_xdr_dissector_t)(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, XDR *xdrs, int hf);
typedef struct vir_dissector_index vir_dissector_index_t;
struct vir_dissector_index {
@@ -146,22 +146,32 @@ static const value_string status_strings[] = {
};
static char *
-G_GNUC_PRINTF(3, 0)
-vir_val_to_str(const uint32_t val,
+G_GNUC_PRINTF(4, 0)
+vir_val_to_str(packet_info *pinfo,
+ const uint32_t val,
const value_string *vs,
const char *fmt)
{
- return val_to_str_wmem(wmem_packet_scope(), val, vs, fmt);
+#if WIRESHARK_VERSION < 4006000
+ return val_to_str_wmem(pinfo->pool, val, vs, fmt);
+#else
+ return val_to_str(pinfo->pool, val, vs, fmt);
+#endif
}
static void
-vir_wmem_free(void *ptr)
+vir_wmem_free(packet_info *pinfo,
+ void *ptr)
{
- wmem_free(wmem_packet_scope(), ptr);
+ wmem_free(pinfo->pool, ptr);
}
static gboolean
-dissect_xdr_string(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
+dissect_xdr_string(tvbuff_t *tvb,
+ packet_info *pinfo G_GNUC_UNUSED,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf,
guint32 maxlen)
{
goffset start;
@@ -179,7 +189,11 @@ dissect_xdr_string(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
}
static gboolean
-dissect_xdr_opaque(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
+dissect_xdr_opaque(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf,
guint32 size)
{
goffset start;
@@ -190,7 +204,7 @@ dissect_xdr_opaque(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
start = xdr_getpos(xdrs);
if ((rc = xdr_opaque(xdrs, (caddr_t)val, size))) {
gint len = xdr_getpos(xdrs) - start;
- const char *s = tvb_bytes_to_str(wmem_packet_scope(), tvb, start, len);
+ const char *s = tvb_bytes_to_str(pinfo->pool, tvb, start, len);
proto_tree_add_bytes_format_value(tree, hf, tvb, start, len, NULL, "%s", s);
} else {
@@ -202,7 +216,11 @@ dissect_xdr_opaque(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
}
static gboolean
-dissect_xdr_bytes(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
+dissect_xdr_bytes(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf,
guint32 maxlen)
{
goffset start;
@@ -212,7 +230,7 @@ dissect_xdr_bytes(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
start = xdr_getpos(xdrs);
if (xdr_bytes(xdrs, (char **)&val, &length, maxlen)) {
gint len = xdr_getpos(xdrs) - start;
- const char *s = tvb_bytes_to_str(wmem_packet_scope(), tvb, start, len);
+ const char *s = tvb_bytes_to_str(pinfo->pool, tvb, start, len);
proto_tree_add_bytes_format_value(tree, hf, tvb, start, len, NULL, "%s", s);
free(val);
@@ -224,7 +242,11 @@ dissect_xdr_bytes(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
}
static gboolean
-dissect_xdr_pointer(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
+dissect_xdr_pointer(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf,
vir_xdr_dissector_t dissect)
{
goffset start;
@@ -236,7 +258,7 @@ dissect_xdr_pointer(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
return FALSE;
}
if (not_null) {
- return dissect(tvb, tree, xdrs, hf);
+ return dissect(tvb, pinfo, tree, xdrs, hf);
} else {
proto_item *ti;
ti = proto_tree_add_item(tree, hf, tvb, start, xdr_getpos(xdrs) - start, ENC_NA);
@@ -246,15 +268,22 @@ dissect_xdr_pointer(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf,
}
static gboolean
-dissect_xdr_iterable(tvbuff_t *tvb, proto_item *ti, XDR *xdrs, gint ett, int rhf,
- guint32 length, vir_xdr_dissector_t dissect, goffset start)
+dissect_xdr_iterable(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_item *ti,
+ XDR *xdrs,
+ gint ett,
+ int rhf,
+ guint32 length,
+ vir_xdr_dissector_t dissect,
+ goffset start)
{
proto_tree *tree;
guint32 i;
tree = proto_item_add_subtree(ti, ett);
for (i = 0; i < length; i++) {
- if (!dissect(tvb, tree, xdrs, rhf))
+ if (!dissect(tvb, pinfo, tree, xdrs, rhf))
return FALSE;
}
proto_item_set_len(ti, xdr_getpos(xdrs) - start);
@@ -262,8 +291,16 @@ dissect_xdr_iterable(tvbuff_t *tvb, proto_item *ti, XDR *xdrs, gint ett, int rhf
}
static gboolean
-dissect_xdr_vector(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf, gint ett,
- int rhf, const gchar *rtype, guint32 size, vir_xdr_dissector_t dissect)
+dissect_xdr_vector(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf,
+ gint ett,
+ int rhf,
+ const gchar *rtype,
+ guint32 size,
+ vir_xdr_dissector_t dissect)
{
goffset start;
proto_item *ti;
@@ -271,12 +308,20 @@ dissect_xdr_vector(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf, gint ett,
start = xdr_getpos(xdrs);
ti = proto_tree_add_item(tree, hf, tvb, start, -1, ENC_NA);
proto_item_append_text(ti, " :: %s[%u]", rtype, size);
- return dissect_xdr_iterable(tvb, ti, xdrs, ett, rhf, size, dissect, start);
+ return dissect_xdr_iterable(tvb, pinfo, ti, xdrs, ett, rhf, size, dissect, start);
}
static gboolean
-dissect_xdr_array(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf, gint ett,
- int rhf, const gchar *rtype, guint32 maxlen, vir_xdr_dissector_t dissect)
+dissect_xdr_array(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf,
+ gint ett,
+ int rhf,
+ const gchar *rtype,
+ guint32 maxlen,
+ vir_xdr_dissector_t dissect)
{
goffset start;
proto_item *ti;
@@ -291,7 +336,7 @@ dissect_xdr_array(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf, gint ett,
ti = proto_tree_add_item(tree, hf, tvb, start, -1, ENC_NA);
proto_item_append_text(ti, " :: %s<%u>", rtype, length);
- return dissect_xdr_iterable(tvb, ti, xdrs, ett, rhf, length, dissect, start);
+ return dissect_xdr_iterable(tvb, pinfo, ti, xdrs, ett, rhf, length, dissect, start);
}
static vir_xdr_dissector_t
@@ -340,7 +385,10 @@ find_payload_dissector(int32_t proc,
}
static void
-dissect_libvirt_stream(tvbuff_t *tvb, proto_tree *tree, gint payload_length)
+dissect_libvirt_stream(tvbuff_t *tvb,
+ packet_info *pinfo G_GNUC_UNUSED,
+ proto_tree *tree,
+ gint payload_length)
{
proto_tree_add_item(tree, hf_libvirt_stream, tvb, VIR_HEADER_LEN,
payload_length - VIR_HEADER_LEN, ENC_NA);
@@ -357,6 +405,7 @@ dissect_libvirt_num_of_fds(tvbuff_t *tvb, proto_tree *tree)
static void
dissect_libvirt_fds(tvbuff_t *tvb G_GNUC_UNUSED,
+ packet_info *pinfo G_GNUC_UNUSED,
gint start G_GNUC_UNUSED,
gint32 nfds G_GNUC_UNUSED)
{
@@ -364,8 +413,12 @@ dissect_libvirt_fds(tvbuff_t *tvb G_GNUC_UNUSED,
}
static void
-dissect_libvirt_payload_xdr_data(tvbuff_t *tvb, proto_tree *tree, gint payload_length,
- gint32 status, vir_xdr_dissector_t dissect)
+dissect_libvirt_payload_xdr_data(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ gint payload_length,
+ gint32 status,
+ vir_xdr_dissector_t dissect)
{
gint32 nfds = 0;
gint start = VIR_HEADER_LEN;
@@ -384,17 +437,21 @@ dissect_libvirt_payload_xdr_data(tvbuff_t *tvb, proto_tree *tree, gint payload_l
payload_data = (caddr_t)tvb_memdup(NULL, payload_tvb, 0, payload_length);
xdrmem_create(&xdrs, payload_data, payload_length, XDR_DECODE);
- dissect(payload_tvb, tree, &xdrs, -1);
+ dissect(payload_tvb, pinfo, tree, &xdrs, -1);
xdr_destroy(&xdrs);
g_free(payload_data);
if (nfds != 0)
- dissect_libvirt_fds(tvb, start + payload_length, nfds);
+ dissect_libvirt_fds(tvb, pinfo, start + payload_length, nfds);
}
static gboolean
-dissect_xdr_stream_hole(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
+dissect_xdr_stream_hole(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ XDR *xdrs,
+ int hf)
{
goffset start;
proto_item *ti;
@@ -411,10 +468,10 @@ dissect_xdr_stream_hole(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
tree = proto_item_add_subtree(ti, ett_libvirt_stream_hole);
hf = hf_libvirt_stream_hole_length;
- if (!dissect_xdr_hyper(tvb, tree, xdrs, hf)) return FALSE;
+ if (!dissect_xdr_hyper(tvb, pinfo, tree, xdrs, hf)) return FALSE;
hf = hf_libvirt_stream_hole_flags;
- if (!dissect_xdr_u_int(tvb, tree, xdrs, hf)) return FALSE;
+ if (!dissect_xdr_u_int(tvb, pinfo, tree, xdrs, hf)) return FALSE;
proto_item_set_len(ti, xdr_getpos(xdrs) - start);
return TRUE;
@@ -424,6 +481,7 @@ dissect_xdr_stream_hole(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
static void
dissect_libvirt_payload(tvbuff_t *tvb,
+ packet_info *pinfo,
proto_tree *tree,
uint32_t prog,
int32_t proc,
@@ -447,13 +505,13 @@ dissect_libvirt_payload(tvbuff_t *tvb,
xd = find_payload_dissector(proc, type, pds, *len);
if (xd == NULL)
goto unknown;
- dissect_libvirt_payload_xdr_data(tvb, tree, payload_length, status, xd);
+ dissect_libvirt_payload_xdr_data(tvb, pinfo, tree, payload_length, status, xd);
} else if (status == VIR_NET_ERROR) {
- dissect_libvirt_payload_xdr_data(tvb, tree, payload_length, status, dissect_xdr_remote_error);
+ dissect_libvirt_payload_xdr_data(tvb, pinfo, tree, payload_length, status, dissect_xdr_remote_error);
} else if (type == VIR_NET_STREAM) { /* implicitly, status == VIR_NET_CONTINUE */
- dissect_libvirt_stream(tvb, tree, payload_length);
+ dissect_libvirt_stream(tvb, pinfo, tree, payload_length);
} else if (type == VIR_NET_STREAM_HOLE) {
- dissect_libvirt_payload_xdr_data(tvb, tree, payload_length, status, dissect_xdr_stream_hole);
+ dissect_libvirt_payload_xdr_data(tvb, pinfo, tree, payload_length, status, dissect_xdr_stream_hole);
} else {
goto unknown;
}
@@ -489,21 +547,21 @@ dissect_libvirt_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
serial = tvb_get_ntohl(tvb, offset); offset += 4;
status = tvb_get_ntohil(tvb, offset); offset += 4;
- prog_str = vir_val_to_str(prog, program_strings, "%x");
+ prog_str = vir_val_to_str(pinfo, prog, program_strings, "%x");
col_add_fstr(pinfo->cinfo, COL_INFO, "Prog=%s", prog_str);
- vir_wmem_free(prog_str);
+ vir_wmem_free(pinfo, prog_str);
vs = get_program_data(prog, VIR_PROGRAM_PROCSTRINGS);
- proc_str = vir_val_to_str(proc, vs, "%d");
+ proc_str = vir_val_to_str(pinfo, proc, vs, "%d");
col_append_fstr(pinfo->cinfo, COL_INFO, " Proc=%s", proc_str);
- vir_wmem_free(proc_str);
+ vir_wmem_free(pinfo, proc_str);
- type_str = vir_val_to_str(type, type_strings, "%d");
- status_str = vir_val_to_str(status, status_strings, "%d");
+ type_str = vir_val_to_str(pinfo, type, type_strings, "%d");
+ status_str = vir_val_to_str(pinfo, status, status_strings, "%d");
col_append_fstr(pinfo->cinfo, COL_INFO, " Type=%s Serial=%u Status=%s",
type_str, serial, status_str);
- vir_wmem_free(status_str);
- vir_wmem_free(type_str);
+ vir_wmem_free(pinfo, status_str);
+ vir_wmem_free(pinfo, type_str);
if (tree) {
gint *hf_proc;
@@ -532,21 +590,26 @@ dissect_libvirt_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
proto_tree_add_item(libvirt_tree, hf_libvirt_status, tvb, offset, 4, ENC_NA); offset += 4;
/* Dissect payload remaining */
- dissect_libvirt_payload(tvb, libvirt_tree, prog, proc, type, status);
+ dissect_libvirt_payload(tvb, pinfo, libvirt_tree, prog, proc, type, status);
}
return 0;
}
static guint
-get_message_len(packet_info *pinfo G_GNUC_UNUSED, tvbuff_t *tvb, int offset, void *data G_GNUC_UNUSED)
+get_message_len(packet_info *pinfo G_GNUC_UNUSED,
+ tvbuff_t *tvb,
+ int offset,
+ void *data G_GNUC_UNUSED)
{
return tvb_get_ntohl(tvb, offset);
}
static int
-dissect_libvirt(tvbuff_t *tvb, packet_info *pinfo,
- proto_tree *tree, void *data G_GNUC_UNUSED)
+dissect_libvirt(tvbuff_t *tvb,
+ packet_info *pinfo,
+ proto_tree *tree,
+ void *data G_GNUC_UNUSED)
{
/* Another magic const - 4; simply, how much bytes
* is needed to tell the length of libvirt packet. */
diff --git a/tools/wireshark/util/genxdrstub.pl b/tools/wireshark/util/genxdrstub.pl
index 01b663a88c..f69695c091 100755
--- a/tools/wireshark/util/genxdrstub.pl
+++ b/tools/wireshark/util/genxdrstub.pl
@@ -250,7 +250,7 @@ sub xdr_type {
sub render_caller {
my ($self, $hfid) = @_;
my $name = $c->rinc( 'dissect_xdr_'.($self->idstrip || lc($self->xdr_type)) );
- "$name(tvb, tree, xdrs, hf)";
+ "$name(tvb, pinfo, tree, xdrs, hf)";
}
sub ft_type {
@@ -345,7 +345,7 @@ BEGIN{::register_profile(
sub render_caller {
my ($self) = @_;
my ($klass) = ref($self) =~ /([^:]+)$/;
- sprintf '%s(tvb, tree, xdrs, hf, %s)',
+ sprintf '%s(tvb, pinfo, tree, xdrs, hf, %s)',
$c->rinc('dissect_xdr_'.lc($klass)),
$c->rinc('dissect_xdr_'.$self->reftype->idstrip);
}
@@ -359,7 +359,7 @@ BEGIN{::register_profile(
sub render_caller {
my ($self, $hfid) = @_;
my ($klass) = ref($self) =~ /([^:]+)$/;
- sprintf '%s(tvb, tree, xdrs, hf, %s)',
+ sprintf '%s(tvb, pinfo, tree, xdrs, hf, %s)',
$c->rinc('dissect_xdr_'.lc($klass)), $self->length || '~0';
}
@@ -447,7 +447,7 @@ BEGIN{::register_profile(
sub render_caller {
my ($self, $hfid) = @_;
my ($pname) = reverse split /__/, $hfid;
- sprintf 'dissect_xdr_array(tvb, tree, xdrs, hf, %s, %s, "%s", %s, %s)',
+ sprintf 'dissect_xdr_array(tvb, pinfo, tree, xdrs, hf, %s, %s, "%s", %s, %s)',
$c->rinc('ett_'.$self->idstrip),
$c->rinc("hf_$hfid\__$pname"),
$self->reftype->idstrip,
@@ -476,7 +476,7 @@ BEGIN{::register_profile(
sub render_caller {
my ($self, $hfid) = @_;
my ($pname) = reverse split /__/, $hfid;
- sprintf 'dissect_xdr_vector(tvb, tree, xdrs, hf, %s, %s, "%s", %s, %s)',
+ sprintf 'dissect_xdr_vector(tvb, pinfo, tree, xdrs, hf, %s, %s, "%s", %s, %s)',
$c->rinc('ett_'.$self->idstrip),
$c->rinc("hf_$hfid\__$pname"),
$self->reftype->idstrip,
@@ -857,7 +857,7 @@ __END__<<DUMMY # Dummy heredoc to disable perl syntax highlighting
my ($self, $ident) = @_;
return if $self->is_primitive;
%>
-static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
+static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, packet_info *pinfo G_GNUC_UNUSED, proto_tree *tree, XDR *xdrs, int hf)
{
return <%= $self->dealias->render_caller($self->ident eq $ident ? undef : $ident) %>;
}
@@ -865,7 +865,7 @@ static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *
<% my ($self, $ident) = @_;
my $hfvar = $c->rinc('hf_'.$self->idstrip);
%>
-static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
+static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, packet_info *pinfo G_GNUC_UNUSED, proto_tree *tree, XDR *xdrs, int hf)
{
goffset start;
proto_item *ti;
@@ -890,7 +890,7 @@ static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *
}
@@ Sym::Type::Enum#render_dissector
<% my ($self, $ident) = @_; %>
-static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
+static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, packet_info *pinfo G_GNUC_UNUSED, proto_tree *tree, XDR *xdrs, int hf)
{
goffset start;
enum { DUMMY } es;
@@ -914,7 +914,7 @@ static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *
my ($self, $ident) = @_;
my $decl_type = $self->decl->type->idstrip;
%>
-static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, proto_tree *tree, XDR *xdrs, int hf)
+static gboolean dissect_xdr_<%= $ident %>(tvbuff_t *tvb, packet_info *pinfo G_GNUC_UNUSED, proto_tree *tree, XDR *xdrs, int hf)
{
gboolean rc = TRUE;
goffset start;
--
2.49.1On Tue, Oct 14, 2025 at 08:31:47 +0200, Michal Privoznik via Devel wrote:
> From: Michal Privoznik <mprivozn@redhat.com>
>
> The main difference is that wmem_packet_scope() is gone [1] but
> the packet_info struct has 'pool` member which points to the
> allocator used for given packet.
>
> Unfortunately, while we were given pointer to packet_info at the
> entry level to our dissector (dissect_libvirt() ->
> tcp_dissect_pdus() -> dissect_libvirt_message()) it was never
> propagated to generated/primitive dissectors.
>
> But not all dissectors need to allocate memory, so mark the new
> argument as unused. And while our generator could be rewritten so
> that the argument is annotated as unused iff it's really unused,
> I couldn't bother rewriting it. It's generated code after all.
> Too much work for little gain.
>
> Another significant change is that val_to_str() now requires new
> argument: pointer to allocator to use because it always allocates
> new memory [2][3].
IMO the change to propagate the struct needed to replace
wmem_packet_scope could be separated from the change to the val_to_str
convertor as it would make the patch a bit more digestable.
Regardless no need to change it now.
>
> 1: https://gitlab.com/wireshark/wireshark/-/commit/5ca5c9ca372e06881b23ba9f4fdcb6b479886444
> 2: https://gitlab.com/wireshark/wireshark/-/commit/b63599762468e4cf1783419a5556377604d344bb
> 3: https://gitlab.com/wireshark/wireshark/-/commit/84799be215313e61b83a3eaf074f89d6ee349b8c
> Resolves: https://gitlab.com/libvirt/libvirt/-/issues/823
> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> ---
> tools/wireshark/src/packet-libvirt.c | 157 +++++++++++++++++++--------
> tools/wireshark/util/genxdrstub.pl | 18 +--
> 2 files changed, 119 insertions(+), 56 deletions(-)
> static char *
> -G_GNUC_PRINTF(3, 0)
> -vir_val_to_str(const uint32_t val,
> +G_GNUC_PRINTF(4, 0)
> +vir_val_to_str(packet_info *pinfo,
> + const uint32_t val,
> const value_string *vs,
> const char *fmt)
> {
> - return val_to_str_wmem(wmem_packet_scope(), val, vs, fmt);
> +#if WIRESHARK_VERSION < 4006000
> + return val_to_str_wmem(pinfo->pool, val, vs, fmt);
> +#else
> + return val_to_str(pinfo->pool, val, vs, fmt);
> +#endif
> }
The above hunk might need some update based on my query in previous
patch.
Once that is solved:
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
On 10/14/25 14:33, Peter Krempa wrote:
> On Tue, Oct 14, 2025 at 08:31:47 +0200, Michal Privoznik via Devel wrote:
>> From: Michal Privoznik <mprivozn@redhat.com>
>>
>> The main difference is that wmem_packet_scope() is gone [1] but
>> the packet_info struct has 'pool` member which points to the
>> allocator used for given packet.
>>
>> Unfortunately, while we were given pointer to packet_info at the
>> entry level to our dissector (dissect_libvirt() ->
>> tcp_dissect_pdus() -> dissect_libvirt_message()) it was never
>> propagated to generated/primitive dissectors.
>>
>> But not all dissectors need to allocate memory, so mark the new
>> argument as unused. And while our generator could be rewritten so
>> that the argument is annotated as unused iff it's really unused,
>> I couldn't bother rewriting it. It's generated code after all.
>> Too much work for little gain.
>>
>> Another significant change is that val_to_str() now requires new
>> argument: pointer to allocator to use because it always allocates
>> new memory [2][3].
>
> IMO the change to propagate the struct needed to replace
> wmem_packet_scope could be separated from the change to the val_to_str
> convertor as it would make the patch a bit more digestable.
Yeah, I thought about that, but the hunk below is basically the only
thing that would be left to do to adapt. So I figured it's not worth the
split.
>
> Regardless no need to change it now.
>
>
>>
>> 1: https://gitlab.com/wireshark/wireshark/-/commit/5ca5c9ca372e06881b23ba9f4fdcb6b479886444
>> 2: https://gitlab.com/wireshark/wireshark/-/commit/b63599762468e4cf1783419a5556377604d344bb
>> 3: https://gitlab.com/wireshark/wireshark/-/commit/84799be215313e61b83a3eaf074f89d6ee349b8c
>> Resolves: https://gitlab.com/libvirt/libvirt/-/issues/823
>> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
>> ---
>> tools/wireshark/src/packet-libvirt.c | 157 +++++++++++++++++++--------
>> tools/wireshark/util/genxdrstub.pl | 18 +--
>> 2 files changed, 119 insertions(+), 56 deletions(-)
>
>
>> static char *
>> -G_GNUC_PRINTF(3, 0)
>> -vir_val_to_str(const uint32_t val,
>> +G_GNUC_PRINTF(4, 0)
>> +vir_val_to_str(packet_info *pinfo,
>> + const uint32_t val,
>> const value_string *vs,
>> const char *fmt)
>> {
>> - return val_to_str_wmem(wmem_packet_scope(), val, vs, fmt);
>> +#if WIRESHARK_VERSION < 4006000
>> + return val_to_str_wmem(pinfo->pool, val, vs, fmt);
>> +#else
>> + return val_to_str(pinfo->pool, val, vs, fmt);
>> +#endif
>> }
>
> The above hunk might need some update based on my query in previous
> patch.
>
I think this clearly shows that val_to_str_wmem() is called on for
wireshark < 4.6.0.
> Once that is solved:
>
> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
>
Thanks,
Michal
© 2016 - 2025 Red Hat, Inc.