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-rw-r--r--src/libsystemd/bus-kernel.c6
-rw-r--r--src/libsystemd/kdbus.h52
2 files changed, 45 insertions, 13 deletions
diff --git a/src/libsystemd/bus-kernel.c b/src/libsystemd/bus-kernel.c
index d69d6f3bc4..d3eeb52425 100644
--- a/src/libsystemd/bus-kernel.c
+++ b/src/libsystemd/bus-kernel.c
@@ -947,8 +947,8 @@ fail:
}
int bus_kernel_read_message(sd_bus *bus) {
+ struct kdbus_cmd_recv recv = {};
struct kdbus_msg *k;
- uint64_t off;
int r;
assert(bus);
@@ -957,14 +957,14 @@ int bus_kernel_read_message(sd_bus *bus) {
if (r < 0)
return r;
- r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &off);
+ r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &recv);
if (r < 0) {
if (errno == EAGAIN)
return 0;
return -errno;
}
- k = (struct kdbus_msg *)((uint8_t *)bus->kdbus_buffer + off);
+ k = (struct kdbus_msg *)((uint8_t *)bus->kdbus_buffer + recv.offset);
if (k->payload_type == KDBUS_PAYLOAD_DBUS) {
r = bus_kernel_make_message(bus, k);
diff --git a/src/libsystemd/kdbus.h b/src/libsystemd/kdbus.h
index d2e4fd301b..10102d4335 100644
--- 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;
@@ -378,6 +380,42 @@ struct kdbus_msg {
} __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
* @KDBUS_POLICY_ACCESS_USER: Grant access to a uid
@@ -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.