bus: update kdbus.h (ABI break)

[elogind.git] / src / libsystemd / kdbus.h

diff --git a/src/libsystemd/kdbus.h b/src/libsystemd/kdbus.h
index d2e4fd301bf07faf42364e59a840195534c3ab96..10102d43358623379f449904b5efb4a715a5786f 100644 (file)
--- a/src/libsystemd/kdbus.h
+++ b/src/libsystemd/kdbus.h
@@ -349,6 +349,7 @@ enum kdbus_payload_type {
  * struct kdbus_msg - the representation of a kdbus message
  * @size:              Total size of the message
  * @flags:             Message flags (KDBUS_MSG_FLAGS_*)
+ * @priority:          Message queue priority value
  * @dst_id:            64-bit ID of the destination connection
  * @src_id:            64-bit ID of the source connection
  * @payload_type:      Payload type (KDBUS_PAYLOAD_*)
@@ -366,6 +367,7 @@ enum kdbus_payload_type {
 struct kdbus_msg {
        __u64 size;
        __u64 flags;
+       __s64 priority;
        __u64 dst_id;
        __u64 src_id;
        __u64 payload_type;
@@ -377,6 +379,42 @@ struct kdbus_msg {
        struct kdbus_item items[0];
 } __attribute__((aligned(8)));
 
+/**
+ * enum kdbus_recv_flags - flags for de-queuing messages
+ * @KDBUS_RECV_PEEK:           Return the next queued message without
+ *                             actually de-queuing it, and without installing
+ *                             any file descriptors or other resources. It is
+ *                             usually used to determine the activating
+ *                             connection of a bus name.
+ * @KDBUS_RECV_DROP:           Drop and free the next queued message and all
+ *                             its resources without actually receiving it.
+ * @KDBUS_RECV_USE_PRIORITY:   Only de-queue messages with the specified or
+ *                             higher priority (lowest values); if not set,
+ *                             the priority value is ignored.
+ */
+enum kdbus_recv_flags {
+       KDBUS_RECV_PEEK         = 1 <<  0,
+       KDBUS_RECV_DROP         = 1 <<  1,
+       KDBUS_RECV_USE_PRIORITY = 1 <<  2,
+};
+
+/**
+ * kdbus_cmd_recv - struct to de-queue a buffered message
+ * @flags:             KDBUS_RECV_* flags
+ * @priority:          Minimum priority of the messages to de-queue. Lowest
+ *                     values have the highest priority.
+ * @offset:            Returned offset in the pool where the message is
+ *                     stored. The user must use KDBUS_CMD_FREE to free
+ *                     the allocated memory.
+ *
+ * This struct is used with the KDBUS_CMD_MSG_RECV ioctl.
+ */
+struct kdbus_cmd_recv {
+       __u64 flags;
+       __s64 priority;
+       __u64 offset;
+} __attribute__((aligned(8)));
+
 /**
  * enum kdbus_policy_access_type - permissions of a policy record
  * @_KDBUS_POLICY_ACCESS_NULL: Uninitialized/invalid
@@ -480,8 +518,7 @@ enum kdbus_attach_flags {
  * @id128:             Unique 128-bit ID of the bus (kernel → userspace)
  * @items:             A list of items
  *
- * This struct is used with the KDBUS_CMD_HELLO ioctl. See the ioctl
- * documentation for more information.
+ * This struct is used with the KDBUS_CMD_HELLO ioctl.
  */
 struct kdbus_cmd_hello {
        __u64 size;
@@ -700,11 +737,6 @@ struct kdbus_cmd_memfd_make {
  *                             placed in the receiver's pool.
  * @KDBUS_CMD_FREE:            Release the allocated memory in the receiver's
  *                             pool.
- * @KDBUS_CMD_DROP:            Drop and free the next queued message and all
- *                             its ressources without actually receiveing it.
- * @KDBUS_CMD_SRC:             Query the sender's connection ID of the next
- *                             queued message, used to determine the activating
- *                             connection of a bus name.
  * @KDBUS_CMD_NAME_ACQUIRE:    Request a well-known bus name to associate with
  *                             the connection. Well-known names are used to
  *                             address a peer on the bus.
@@ -759,10 +791,8 @@ enum kdbus_ioctl_type {
        KDBUS_CMD_BYEBYE =              _IO  (KDBUS_IOC_MAGIC, 0x31),
 
        KDBUS_CMD_MSG_SEND =            _IOW (KDBUS_IOC_MAGIC, 0x40, struct kdbus_msg),
-       KDBUS_CMD_MSG_RECV =            _IOR (KDBUS_IOC_MAGIC, 0x41, __u64 *),
+       KDBUS_CMD_MSG_RECV =            _IOWR(KDBUS_IOC_MAGIC, 0x41, struct kdbus_cmd_recv),
        KDBUS_CMD_FREE =                _IOW (KDBUS_IOC_MAGIC, 0x42, __u64 *),
-       KDBUS_CMD_MSG_DROP =            _IO  (KDBUS_IOC_MAGIC, 0x43),
-       KDBUS_CMD_MSG_SRC =             _IOR (KDBUS_IOC_MAGIC, 0x44, __u64 *),
 
        KDBUS_CMD_NAME_ACQUIRE =        _IOWR(KDBUS_IOC_MAGIC, 0x50, struct kdbus_cmd_name),
        KDBUS_CMD_NAME_RELEASE =        _IOW (KDBUS_IOC_MAGIC, 0x51, struct kdbus_cmd_name),
@@ -827,6 +857,8 @@ enum kdbus_ioctl_type {
  * @ENOENT:            The name to query information about is currently not on
  *                     the bus.
  * @ENOMEM:            Out of memory.
+ * @ENOMSG:            The queue is not empty, but no message with a matching
+ *                     priority is currently queued.
  * @ENOSYS:            The requested functionality is not available.
  * @ENOTSUPP:          The feature negotiation failed, a not supported feature
  *                     was requested, or an unknown item type was received.