sd-bus: sync kdbus.h (ABI break)

In kdbus.h, the 'features' field has been dropped again. Instead of
negotiating features that way, we decided to make the kernel return the
set of supported flags in each ioctl struct's .flags field, in both the
success and error cases.

1 files changed, 10 insertions, 21 deletions

diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index c3dbc837d7..ac0ae5366e 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -751,10 +751,9 @@ int bus_kernel_take_fd(sd_bus *b) {
                 }
         }
 
-        /* The higher 32bit of both flags fields are considered
+        /* The higher 32bit of the bus_flags fields are considered
          * 'incompatible flags'. Refuse them all for now. */
-        if (hello->bus_flags > 0xFFFFFFFFULL ||
-            hello->conn_flags > 0xFFFFFFFFULL)
+        if (hello->bus_flags > 0xFFFFFFFFULL)
                 return -ENOTSUP;
 
         if (!bloom_validate_parameters((size_t) hello->bloom.size, (unsigned) hello->bloom.n_hash))
@@ -821,6 +820,7 @@ static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
 
 int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m, bool hint_sync_call) {
         int r;
+        uint64_t flags;
 
         assert(bus);
         assert(m);
@@ -843,7 +843,12 @@ int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m, bool hint_sync_call
         if (hint_sync_call)
                 m->kdbus->flags |= KDBUS_MSG_FLAGS_EXPECT_REPLY|KDBUS_MSG_FLAGS_SYNC_REPLY;
 
+        /* The kernel will return the set of supported flags in m->kdbus->flags.
+         * Save the current message flags before issuing the ioctl, and restore them
+         * afterwards */
+        flags = m->kdbus->flags;
         r = ioctl(bus->output_fd, KDBUS_CMD_MSG_SEND, m->kdbus);
+        m->kdbus->flags = flags;
         if (r < 0) {
                 _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
                 sd_bus_message *reply;
@@ -1307,13 +1312,6 @@ int bus_kernel_create_bus(const char *name, bool world, char **s) {
                 return -errno;
         }
 
-        /* The features field are considered 'incompatible flags'.
-         * Refuse them all for now. */
-        if (make->features) {
-                safe_close(fd);
-                return -ENOTSUP;
-        }
-
         if (s) {
                 char *p;
 
@@ -1444,13 +1442,6 @@ int bus_kernel_create_endpoint(const char *bus_name, const char *ep_name, char *
                 return -errno;
         }
 
-        /* The features field are considered 'incompatible flags'.
-         * Refuse them all for now. */
-        if (make->features) {
-                safe_close(fd);
-                return -ENOTSUP;
-        }
-
         if (ep_path) {
                 char *p;
 
@@ -1574,11 +1565,9 @@ int bus_kernel_make_starter(
         if (ioctl(fd, KDBUS_CMD_HELLO, hello) < 0)
                 return -errno;
 
-        /* The higher 32bit of both flags fields are considered
+        /* The higher 32bit of the bus_flags fields are considered
          * 'incompatible flags'. Refuse them all for now. */
-        if (hello->features ||
-            hello->bus_flags > 0xFFFFFFFFULL ||
-            hello->conn_flags > 0xFFFFFFFFULL)
+        if (hello->bus_flags > 0xFFFFFFFFULL)
                 return -ENOTSUP;
 
         if (!bloom_validate_parameters((size_t) hello->bloom.size, (unsigned) hello->bloom.n_hash))