connection.c: Align pointer extra storage correctly

Most extra data are just pointers, but in case of fds we store an int in
the extra space.  That can cause un-aligned access to pointers on 64 bit
architectures.  Make sure we always align pointer storage correctly.

diff --git a/src/connection.c b/src/connection.c
index 141875e..8707d40 100644 (file)
--- a/src/connection.c
+++ b/src/connection.c
@@ -378,23 +378,28 @@ wl_connection_queue(struct wl_connection *connection,
        return 0;
 }
 
+#define ALIGN(p, s) (void *) ( ((intptr_t) (p) + ((s) - 1)) & ~((s) - 1) )
+
 static int
 wl_message_size_extra(const struct wl_message *message)
 {
-       int i, extra;
-
-       for (i = 0, extra = 0; message->signature[i]; i++) {
+       char *extra;
+       int i;
 
+       for (i = 0, extra = NULL; message->signature[i]; i++) {
                switch (message->signature[i]) {
                case 's':
                case 'o':
                case 'n':
+                       extra = ALIGN(extra, sizeof (void *));
                        extra += sizeof (void *);
                        break;
                case 'a':
+                       extra = ALIGN(extra, sizeof (void *));
                        extra += sizeof (void *) + sizeof (struct wl_array);
                        break;
                case 'h':
+                       extra = ALIGN(extra, sizeof (int));
                        extra += sizeof (int);
                        break;
                default:
@@ -402,7 +407,7 @@ wl_message_size_extra(const struct wl_message *message)
                }
        }
 
-       return extra;
+       return (intptr_t) extra;
 }
 
 static int
@@ -501,6 +506,7 @@ wl_closure_vmarshal(struct wl_object *sender,
                        *p++ = va_arg(ap, int32_t);
                        break;
                case 's':
+                       extra = ALIGN(extra, sizeof (void *));
                        closure->types[i] = &ffi_type_pointer;
                        closure->args[i] = extra;
                        sp = (const char **) extra;
@@ -527,6 +533,7 @@ wl_closure_vmarshal(struct wl_object *sender,
                        p += aligned / sizeof *p;
                        break;
                case 'o':
+                       extra = ALIGN(extra, sizeof (void *));
                        closure->types[i] = &ffi_type_pointer;
                        closure->args[i] = extra;
                        objectp = (struct wl_object **) extra;
@@ -557,6 +564,7 @@ wl_closure_vmarshal(struct wl_object *sender,
                        break;
 
                case 'a':
+                       extra = ALIGN(extra, sizeof (void *));
                        closure->types[i] = &ffi_type_pointer;
                        closure->args[i] = extra;
                        arrayp = (struct wl_array **) extra;
@@ -589,6 +597,7 @@ wl_closure_vmarshal(struct wl_object *sender,
                        break;
 
                case 'h':
+                       extra = ALIGN(extra, sizeof (int));
                        closure->types[i] = &ffi_type_sint;
                        closure->args[i] = extra;
                        fd_ptr = (int *) extra;
@@ -715,6 +724,7 @@ wl_connection_demarshal(struct wl_connection *connection,
                                goto err;
                        }
 
+                       extra = ALIGN(extra, sizeof (void *));
                        s = (char **) extra;
                        extra += sizeof *s;
                        closure->args[i] = s;
@@ -736,6 +746,7 @@ wl_connection_demarshal(struct wl_connection *connection,
                        break;
                case 'o':
                        closure->types[i] = &ffi_type_pointer;
+                       extra = ALIGN(extra, sizeof (void *));
                        id = (uint32_t **) extra;
                        extra += sizeof *id;
                        closure->args[i] = id;
@@ -753,6 +764,7 @@ wl_connection_demarshal(struct wl_connection *connection,
                        break;
                case 'n':
                        closure->types[i] = &ffi_type_pointer;
+                       extra = ALIGN(extra, sizeof (void *));
                        id = (uint32_t **) extra;
                        extra += sizeof *id;
                        closure->args[i] = id;
@@ -789,6 +801,7 @@ wl_connection_demarshal(struct wl_connection *connection,
                                goto err;
                        }
 
+                       extra = ALIGN(extra, sizeof (void *));
                        array = (struct wl_array **) extra;
                        extra += sizeof *array;
                        closure->args[i] = array;
@@ -804,6 +817,7 @@ wl_connection_demarshal(struct wl_connection *connection,
                case 'h':
                        closure->types[i] = &ffi_type_sint;
 
+                       extra = ALIGN(extra, sizeof (int));
                        fd = (int *) extra;
                        extra += sizeof *fd;
                        closure->args[i] = fd;