marshaller: track if add_fd() was given -1

In some cases, it might be worth to be able to send a message with a -1
fd, has the protocol permits. Change add_fd/get_fd in order to track
if the caller wanted to send -1.

Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Acked-by: Frediano Ziglio <fziglio@redhat.com>

2 files changed, 17 insertions, 9 deletions

diff --git a/common/marshaller.c b/common/marshaller.c
index c1d208e..cffc641 100644
--- a/common/marshaller.c
+++ b/common/marshaller.c
@@ -87,6 +87,7 @@ struct SpiceMarshaller {
     MarshallerItem *items;
 
     MarshallerItem static_items[N_STATIC_ITEMS];
+    bool has_fd;
     int fd;
 };
 
@@ -624,19 +625,25 @@ void *spice_marshaller_add_int8(SpiceMarshaller *m, int8_t v)
 
 void spice_marshaller_add_fd(SpiceMarshaller *m, int fd)
 {
-    spice_assert(m->fd == -1);
+    spice_assert(m->has_fd == false);
 
-    m->fd = dup(fd);
-    if (m->fd == -1) {
-        perror("dup");
+    m->has_fd = true;
+    if (fd != -1) {
+        m->fd = dup(fd);
+        if (m->fd == -1) {
+            perror("dup");
+        }
+    } else {
+        m->fd = -1;
     }
 }
 
-int spice_marshaller_get_fd(SpiceMarshaller *m)
+bool spice_marshaller_get_fd(SpiceMarshaller *m, int *fd)
 {
-    int fd = m->fd;
+    bool had_fd = m->has_fd;
 
-    m->fd = -1;
+    *fd = m->fd;
+    m->has_fd = false;
 
-    return fd;
+    return had_fd;
 }
diff --git a/common/marshaller.h b/common/marshaller.h
index 9f9c3ad..316184e 100644
--- a/common/marshaller.h
+++ b/common/marshaller.h
@@ -19,6 +19,7 @@
 #ifndef _H_MARSHALLER
 #define _H_MARSHALLER
 
+#include <stdbool.h>
 #include <spice/macros.h>
 #include <spice/types.h>
 #include "mem.h"
@@ -67,7 +68,7 @@ void *spice_marshaller_add_int8(SpiceMarshaller *m, int8_t v);
 void  spice_marshaller_set_uint32(SpiceMarshaller *m, void *ref, uint32_t v);
 
 void  spice_marshaller_add_fd(SpiceMarshaller *m, int fd);
-int   spice_marshaller_get_fd(SpiceMarshaller *m);
+bool  spice_marshaller_get_fd(SpiceMarshaller *m, int *fd);
 
 SPICE_END_DECLS