[PATCH 02/14] kdbus: add uapi header file

[Greg Kroah-Hartman]

From: Daniel Mack <daniel@xxxxxxxxxx>

This patch adds the header file which describes the low-level
transport protocol used by various ioctls. The header file is located
in include/uapi/linux/ as it is shared between kernel and userspace,
and it only contains data structure definitions, enums and defines
for constants.

The low-level kernel API of kdbus is exposed through ioctls, employed
on nodes exposed by kdbusfs. We've chosen a ioctl-based implementation
over syscalls for various reaons:

 * The ioctls kdbus offers are completely specific to nodes exposed by
   kdbusfs and can not be applied to any other file descriptor in a
   system.

 * The file descriptors derived from opening nodes in kdbusfs can only be
   used for poll(), close() and the ioctls described in kdbus.h.

 * Not all systems will make use of kdbus eventually, and we want to
   make as many parts of the kernel optional at build time.

 * We want to build the kdbus code as module, which is impossible to
   do when implemented with syscalls.

 * The ioctl dispatching logic does not show up in our performance
   graphs; its overhead is negligible.

 * For development, being able to build, load and unload a separate
   module with a versioned name suffix is essential.

Signed-off-by: Daniel Mack <daniel@xxxxxxxxxx>
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
Signed-off-by: Djalal Harouni <tixxdz@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/uapi/linux/Kbuild  |   1 +
 include/uapi/linux/kdbus.h | 979 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 980 insertions(+)
 create mode 100644 include/uapi/linux/kdbus.h

diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 68ceb97c458c..ddc413e1959f 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -214,6 +214,7 @@ header-y += ixjuser.h
 header-y += jffs2.h
 header-y += joystick.h
 header-y += kcmp.h
+header-y += kdbus.h
 header-y += kdev_t.h
 header-y += kd.h
 header-y += kernelcapi.h
diff --git a/include/uapi/linux/kdbus.h b/include/uapi/linux/kdbus.h
new file mode 100644
index 000000000000..fc1d77dd7c93
--- /dev/null
+++ b/include/uapi/linux/kdbus.h
@@ -0,0 +1,979 @@
+/*
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#ifndef _KDBUS_UAPI_H_
+#define _KDBUS_UAPI_H_
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define KDBUS_IOCTL_MAGIC		0x95
+#define KDBUS_SRC_ID_KERNEL		(0)
+#define KDBUS_DST_ID_NAME		(0)
+#define KDBUS_MATCH_ID_ANY		(~0ULL)
+#define KDBUS_DST_ID_BROADCAST		(~0ULL)
+#define KDBUS_FLAG_NEGOTIATE		(1ULL << 63)
+
+/**
+ * struct kdbus_notify_id_change - name registry change message
+ * @id:			New or former owner of the name
+ * @flags:		flags field from KDBUS_HELLO_*
+ *
+ * Sent from kernel to userspace when the owner or activator of
+ * a well-known name changes.
+ *
+ * Attached to:
+ *   KDBUS_ITEM_ID_ADD
+ *   KDBUS_ITEM_ID_REMOVE
+ */
+struct kdbus_notify_id_change {
+	__u64 id;
+	__u64 flags;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_notify_name_change - name registry change message
+ * @old_id:		ID and flags of former owner of a name
+ * @new_id:		ID and flags of new owner of a name
+ * @name:		Well-known name
+ *
+ * Sent from kernel to userspace when the owner or activator of
+ * a well-known name changes.
+ *
+ * Attached to:
+ *   KDBUS_ITEM_NAME_ADD
+ *   KDBUS_ITEM_NAME_REMOVE
+ *   KDBUS_ITEM_NAME_CHANGE
+ */
+struct kdbus_notify_name_change {
+	struct kdbus_notify_id_change old_id;
+	struct kdbus_notify_id_change new_id;
+	char name[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_creds - process credentials
+ * @uid:		User ID
+ * @euid:		Effective UID
+ * @suid:		Saved UID
+ * @fsuid:		Filesystem UID
+ * @gid:		Group ID
+ * @egid:		Effective GID
+ * @sgid:		Saved GID
+ * @fsgid:		Filesystem GID
+ *
+ * Attached to:
+ *   KDBUS_ITEM_CREDS
+ */
+struct kdbus_creds {
+	__u64 uid;
+	__u64 euid;
+	__u64 suid;
+	__u64 fsuid;
+	__u64 gid;
+	__u64 egid;
+	__u64 sgid;
+	__u64 fsgid;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_pids - process identifiers
+ * @pid:		Process ID
+ * @tid:		Thread ID
+ * @ppid:		Parent process ID
+ *
+ * The PID and TID of a process.
+ *
+ * Attached to:
+ *   KDBUS_ITEM_PIDS
+ */
+struct kdbus_pids {
+	__u64 pid;
+	__u64 tid;
+	__u64 ppid;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_caps - process capabilities
+ * @last_cap:	Highest currently known capability bit
+ * @caps:	Variable number of 32-bit capabilities flags
+ *
+ * Contains a variable number of 32-bit capabilities flags.
+ *
+ * Attached to:
+ *   KDBUS_ITEM_CAPS
+ */
+struct kdbus_caps {
+	__u32 last_cap;
+	__u32 caps[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_audit - audit information
+ * @sessionid:		The audit session ID
+ * @loginuid:		The audit login uid
+ *
+ * Attached to:
+ *   KDBUS_ITEM_AUDIT
+ */
+struct kdbus_audit {
+	__u32 sessionid;
+	__u32 loginuid;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_timestamp
+ * @seqnum:		Global per-domain message sequence number
+ * @monotonic_ns:	Monotonic timestamp, in nanoseconds
+ * @realtime_ns:	Realtime timestamp, in nanoseconds
+ *
+ * Attached to:
+ *   KDBUS_ITEM_TIMESTAMP
+ */
+struct kdbus_timestamp {
+	__u64 seqnum;
+	__u64 monotonic_ns;
+	__u64 realtime_ns;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_vec - I/O vector for kdbus payload items
+ * @size:		The size of the vector
+ * @address:		Memory address of data buffer
+ * @offset:		Offset in the in-message payload memory,
+ *			relative to the message head
+ *
+ * Attached to:
+ *   KDBUS_ITEM_PAYLOAD_VEC, KDBUS_ITEM_PAYLOAD_OFF
+ */
+struct kdbus_vec {
+	__u64 size;
+	union {
+		__u64 address;
+		__u64 offset;
+	};
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_bloom_parameter - bus-wide bloom parameters
+ * @size:		Size of the bit field in bytes (m / 8)
+ * @n_hash:		Number of hash functions used (k)
+ */
+struct kdbus_bloom_parameter {
+	__u64 size;
+	__u64 n_hash;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_bloom_filter - bloom filter containing n elements
+ * @generation:		Generation of the element set in the filter
+ * @data:		Bit field, multiple of 8 bytes
+ */
+struct kdbus_bloom_filter {
+	__u64 generation;
+	__u64 data[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_memfd - a kdbus memfd
+ * @start:		The offset into the memfd where the segment starts
+ * @size:		The size of the memfd segment
+ * @fd:			The file descriptor number
+ * @__pad:		Padding to ensure proper alignment and size
+ *
+ * Attached to:
+ *   KDBUS_ITEM_PAYLOAD_MEMFD
+ */
+struct kdbus_memfd {
+	__u64 start;
+	__u64 size;
+	int fd;
+	__u32 __pad;
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_name - a registered well-known name with its flags
+ * @flags:		Flags from KDBUS_NAME_*
+ * @name:		Well-known name
+ *
+ * Attached to:
+ *   KDBUS_ITEM_OWNED_NAME
+ */
+struct kdbus_name {
+	__u64 flags;
+	char name[0];
+} __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
+ * @KDBUS_POLICY_ACCESS_GROUP:	Grant access to gid
+ * @KDBUS_POLICY_ACCESS_WORLD:	World-accessible
+ */
+enum kdbus_policy_access_type {
+	_KDBUS_POLICY_ACCESS_NULL,
+	KDBUS_POLICY_ACCESS_USER,
+	KDBUS_POLICY_ACCESS_GROUP,
+	KDBUS_POLICY_ACCESS_WORLD,
+};
+
+/**
+ * enum kdbus_policy_access_flags - mode flags
+ * @KDBUS_POLICY_OWN:		Allow to own a well-known name
+ *				Implies KDBUS_POLICY_TALK and KDBUS_POLICY_SEE
+ * @KDBUS_POLICY_TALK:		Allow communication to a well-known name
+ *				Implies KDBUS_POLICY_SEE
+ * @KDBUS_POLICY_SEE:		Allow to see a well-known name
+ */
+enum kdbus_policy_type {
+	KDBUS_POLICY_SEE	= 0,
+	KDBUS_POLICY_TALK,
+	KDBUS_POLICY_OWN,
+};
+
+/**
+ * struct kdbus_policy_access - policy access item
+ * @type:		One of KDBUS_POLICY_ACCESS_* types
+ * @access:		Access to grant
+ * @id:			For KDBUS_POLICY_ACCESS_USER, the uid
+ *			For KDBUS_POLICY_ACCESS_GROUP, the gid
+ */
+struct kdbus_policy_access {
+	__u64 type;	/* USER, GROUP, WORLD */
+	__u64 access;	/* OWN, TALK, SEE */
+	__u64 id;	/* uid, gid, 0 */
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_attach_flags - flags for metadata attachments
+ * @KDBUS_ATTACH_TIMESTAMP:		Timestamp
+ * @KDBUS_ATTACH_CREDS:			Credentials
+ * @KDBUS_ATTACH_PIDS:			PIDs
+ * @KDBUS_ATTACH_AUXGROUPS:		Auxiliary groups
+ * @KDBUS_ATTACH_NAMES:			Well-known names
+ * @KDBUS_ATTACH_TID_COMM:		The "comm" process identifier of the TID
+ * @KDBUS_ATTACH_PID_COMM:		The "comm" process identifier of the PID
+ * @KDBUS_ATTACH_EXE:			The path of the executable
+ * @KDBUS_ATTACH_CMDLINE:		The process command line
+ * @KDBUS_ATTACH_CGROUP:		The croup membership
+ * @KDBUS_ATTACH_CAPS:			The process capabilities
+ * @KDBUS_ATTACH_SECLABEL:		The security label
+ * @KDBUS_ATTACH_AUDIT:			The audit IDs
+ * @KDBUS_ATTACH_CONN_DESCRIPTION:	The human-readable connection name
+ * @_KDBUS_ATTACH_ALL:			All of the above
+ * @_KDBUS_ATTACH_ANY:			Wildcard match to enable any kind of
+ *					metatdata.
+ */
+enum kdbus_attach_flags {
+	KDBUS_ATTACH_TIMESTAMP		=  1ULL <<  0,
+	KDBUS_ATTACH_CREDS		=  1ULL <<  1,
+	KDBUS_ATTACH_PIDS		=  1ULL <<  2,
+	KDBUS_ATTACH_AUXGROUPS		=  1ULL <<  3,
+	KDBUS_ATTACH_NAMES		=  1ULL <<  4,
+	KDBUS_ATTACH_TID_COMM		=  1ULL <<  5,
+	KDBUS_ATTACH_PID_COMM		=  1ULL <<  6,
+	KDBUS_ATTACH_EXE		=  1ULL <<  7,
+	KDBUS_ATTACH_CMDLINE		=  1ULL <<  8,
+	KDBUS_ATTACH_CGROUP		=  1ULL <<  9,
+	KDBUS_ATTACH_CAPS		=  1ULL << 10,
+	KDBUS_ATTACH_SECLABEL		=  1ULL << 11,
+	KDBUS_ATTACH_AUDIT		=  1ULL << 12,
+	KDBUS_ATTACH_CONN_DESCRIPTION	=  1ULL << 13,
+	_KDBUS_ATTACH_ALL		=  (1ULL << 14) - 1,
+	_KDBUS_ATTACH_ANY		=  ~0ULL
+};
+
+/**
+ * enum kdbus_item_type - item types to chain data in a list
+ * @_KDBUS_ITEM_NULL:			Uninitialized/invalid
+ * @_KDBUS_ITEM_USER_BASE:		Start of user items
+ * @KDBUS_ITEM_NEGOTIATE:		Negotiate supported items
+ * @KDBUS_ITEM_PAYLOAD_VEC:		Vector to data
+ * @KDBUS_ITEM_PAYLOAD_OFF:		Data at returned offset to message head
+ * @KDBUS_ITEM_PAYLOAD_MEMFD:		Data as sealed memfd
+ * @KDBUS_ITEM_FDS:			Attached file descriptors
+ * @KDBUS_ITEM_CANCEL_FD:		FD used to cancel a synchronous
+ *					operation by writing to it from
+ *					userspace
+ * @KDBUS_ITEM_BLOOM_PARAMETER:		Bus-wide bloom parameters, used with
+ *					KDBUS_CMD_BUS_MAKE, carries a
+ *					struct kdbus_bloom_parameter
+ * @KDBUS_ITEM_BLOOM_FILTER:		Bloom filter carried with a message,
+ *					used to match against a bloom mask of a
+ *					connection, carries a struct
+ *					kdbus_bloom_filter
+ * @KDBUS_ITEM_BLOOM_MASK:		Bloom mask used to match against a
+ *					message'sbloom filter
+ * @KDBUS_ITEM_DST_NAME:		Destination's well-known name
+ * @KDBUS_ITEM_MAKE_NAME:		Name of domain, bus, endpoint
+ * @KDBUS_ITEM_ATTACH_FLAGS_SEND:	Attach-flags, used for updating which
+ *					metadata a connection opts in to send
+ * @KDBUS_ITEM_ATTACH_FLAGS_RECV:	Attach-flags, used for updating which
+ *					metadata a connection requests to
+ *					receive for each reeceived message
+ * @KDBUS_ITEM_ID:			Connection ID
+ * @KDBUS_ITEM_NAME:			Well-know name with flags
+ * @_KDBUS_ITEM_ATTACH_BASE:		Start of metadata attach items
+ * @KDBUS_ITEM_TIMESTAMP:		Timestamp
+ * @KDBUS_ITEM_CREDS:			Process credentials
+ * @KDBUS_ITEM_PIDS:			Process identifiers
+ * @KDBUS_ITEM_AUXGROUPS:		Auxiliary process groups
+ * @KDBUS_ITEM_OWNED_NAME:		A name owned by the associated
+ *					connection
+ * @KDBUS_ITEM_TID_COMM:		Thread ID "comm" identifier
+ *					(Don't trust this, see below.)
+ * @KDBUS_ITEM_PID_COMM:		Process ID "comm" identifier
+ *					(Don't trust this, see below.)
+ * @KDBUS_ITEM_EXE:			The path of the executable
+ *					(Don't trust this, see below.)
+ * @KDBUS_ITEM_CMDLINE:			The process command line
+ *					(Don't trust this, see below.)
+ * @KDBUS_ITEM_CGROUP:			The croup membership
+ * @KDBUS_ITEM_CAPS:			The process capabilities
+ * @KDBUS_ITEM_SECLABEL:		The security label
+ * @KDBUS_ITEM_AUDIT:			The audit IDs
+ * @KDBUS_ITEM_CONN_DESCRIPTION:	The connection's human-readable name
+ *					(debugging)
+ * @_KDBUS_ITEM_POLICY_BASE:		Start of policy items
+ * @KDBUS_ITEM_POLICY_ACCESS:		Policy access block
+ * @_KDBUS_ITEM_KERNEL_BASE:		Start of kernel-generated message items
+ * @KDBUS_ITEM_NAME_ADD:		Notification in kdbus_notify_name_change
+ * @KDBUS_ITEM_NAME_REMOVE:		Notification in kdbus_notify_name_change
+ * @KDBUS_ITEM_NAME_CHANGE:		Notification in kdbus_notify_name_change
+ * @KDBUS_ITEM_ID_ADD:			Notification in kdbus_notify_id_change
+ * @KDBUS_ITEM_ID_REMOVE:		Notification in kdbus_notify_id_change
+ * @KDBUS_ITEM_REPLY_TIMEOUT:		Timeout has been reached
+ * @KDBUS_ITEM_REPLY_DEAD:		Destination died
+ *
+ * N.B: The process and thread COMM fields, as well as the CMDLINE and
+ * EXE fields may be altered by unprivileged processes und should
+ * hence *not* used for security decisions. Peers should make use of
+ * these items only for informational purposes, such as generating log
+ * records.
+ */
+enum kdbus_item_type {
+	_KDBUS_ITEM_NULL,
+	_KDBUS_ITEM_USER_BASE,
+	KDBUS_ITEM_NEGOTIATE	= _KDBUS_ITEM_USER_BASE,
+	KDBUS_ITEM_PAYLOAD_VEC,
+	KDBUS_ITEM_PAYLOAD_OFF,
+	KDBUS_ITEM_PAYLOAD_MEMFD,
+	KDBUS_ITEM_FDS,
+	KDBUS_ITEM_CANCEL_FD,
+	KDBUS_ITEM_BLOOM_PARAMETER,
+	KDBUS_ITEM_BLOOM_FILTER,
+	KDBUS_ITEM_BLOOM_MASK,
+	KDBUS_ITEM_DST_NAME,
+	KDBUS_ITEM_MAKE_NAME,
+	KDBUS_ITEM_ATTACH_FLAGS_SEND,
+	KDBUS_ITEM_ATTACH_FLAGS_RECV,
+	KDBUS_ITEM_ID,
+	KDBUS_ITEM_NAME,
+
+	/* keep these item types in sync with KDBUS_ATTACH_* flags */
+	_KDBUS_ITEM_ATTACH_BASE	= 0x1000,
+	KDBUS_ITEM_TIMESTAMP	= _KDBUS_ITEM_ATTACH_BASE,
+	KDBUS_ITEM_CREDS,
+	KDBUS_ITEM_PIDS,
+	KDBUS_ITEM_AUXGROUPS,
+	KDBUS_ITEM_OWNED_NAME,
+	KDBUS_ITEM_TID_COMM,
+	KDBUS_ITEM_PID_COMM,
+	KDBUS_ITEM_EXE,
+	KDBUS_ITEM_CMDLINE,
+	KDBUS_ITEM_CGROUP,
+	KDBUS_ITEM_CAPS,
+	KDBUS_ITEM_SECLABEL,
+	KDBUS_ITEM_AUDIT,
+	KDBUS_ITEM_CONN_DESCRIPTION,
+
+	_KDBUS_ITEM_POLICY_BASE	= 0x2000,
+	KDBUS_ITEM_POLICY_ACCESS = _KDBUS_ITEM_POLICY_BASE,
+
+	_KDBUS_ITEM_KERNEL_BASE	= 0x8000,
+	KDBUS_ITEM_NAME_ADD	= _KDBUS_ITEM_KERNEL_BASE,
+	KDBUS_ITEM_NAME_REMOVE,
+	KDBUS_ITEM_NAME_CHANGE,
+	KDBUS_ITEM_ID_ADD,
+	KDBUS_ITEM_ID_REMOVE,
+	KDBUS_ITEM_REPLY_TIMEOUT,
+	KDBUS_ITEM_REPLY_DEAD,
+};
+
+/**
+ * struct kdbus_item - chain of data blocks
+ * @size:		Overall data record size
+ * @type:		Kdbus_item type of data
+ * @data:		Generic bytes
+ * @data32:		Generic 32 bit array
+ * @data64:		Generic 64 bit array
+ * @str:		Generic string
+ * @id:			Connection ID
+ * @vec:		KDBUS_ITEM_PAYLOAD_VEC
+ * @creds:		KDBUS_ITEM_CREDS
+ * @audit:		KDBUS_ITEM_AUDIT
+ * @timestamp:		KDBUS_ITEM_TIMESTAMP
+ * @name:		KDBUS_ITEM_NAME
+ * @bloom_parameter:	KDBUS_ITEM_BLOOM_PARAMETER
+ * @bloom_filter:	KDBUS_ITEM_BLOOM_FILTER
+ * @memfd:		KDBUS_ITEM_PAYLOAD_MEMFD
+ * @name_change:	KDBUS_ITEM_NAME_ADD
+ *			KDBUS_ITEM_NAME_REMOVE
+ *			KDBUS_ITEM_NAME_CHANGE
+ * @id_change:		KDBUS_ITEM_ID_ADD
+ *			KDBUS_ITEM_ID_REMOVE
+ * @policy:		KDBUS_ITEM_POLICY_ACCESS
+ */
+struct kdbus_item {
+	__u64 size;
+	__u64 type;
+	union {
+		__u8 data[0];
+		__u32 data32[0];
+		__u64 data64[0];
+		char str[0];
+
+		__u64 id;
+		struct kdbus_vec vec;
+		struct kdbus_creds creds;
+		struct kdbus_pids pids;
+		struct kdbus_audit audit;
+		struct kdbus_caps caps;
+		struct kdbus_timestamp timestamp;
+		struct kdbus_name name;
+		struct kdbus_bloom_parameter bloom_parameter;
+		struct kdbus_bloom_filter bloom_filter;
+		struct kdbus_memfd memfd;
+		int fds[0];
+		struct kdbus_notify_name_change name_change;
+		struct kdbus_notify_id_change id_change;
+		struct kdbus_policy_access policy_access;
+	};
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_msg_flags - type of message
+ * @KDBUS_MSG_EXPECT_REPLY:	Expect a reply message, used for
+ *				method calls. The userspace-supplied
+ *				cookie identifies the message and the
+ *				respective reply carries the cookie
+ *				in cookie_reply
+ * @KDBUS_MSG_NO_AUTO_START:	Do not start a service if the addressed
+ *				name is not currently active. This flag is
+ *				not looked at by the kernel but only
+ *				serves as hint for userspace implementations.
+ * @KDBUS_MSG_SIGNAL:		Treat this message as signal
+ */
+enum kdbus_msg_flags {
+	KDBUS_MSG_EXPECT_REPLY	= 1ULL << 0,
+	KDBUS_MSG_NO_AUTO_START	= 1ULL << 1,
+	KDBUS_MSG_SIGNAL	= 1ULL << 2,
+};
+
+/**
+ * enum kdbus_payload_type - type of payload carried by message
+ * @KDBUS_PAYLOAD_KERNEL:	Kernel-generated simple message
+ * @KDBUS_PAYLOAD_DBUS:		D-Bus marshalling "DBusDBus"
+ *
+ * Any payload-type is accepted. Common types will get added here once
+ * established.
+ */
+enum kdbus_payload_type {
+	KDBUS_PAYLOAD_KERNEL,
+	KDBUS_PAYLOAD_DBUS	= 0x4442757344427573ULL,
+};
+
+/**
+ * struct kdbus_msg - the representation of a kdbus message
+ * @size:		Total size of the message
+ * @flags:		Message flags (KDBUS_MSG_*), userspace â kernel
+ * @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_*)
+ * @cookie:		Userspace-supplied cookie, for the connection
+ *			to identify its messages
+ * @timeout_ns:		The time to wait for a message reply from the peer.
+ *			If there is no reply, and the send command is
+ *			executed asynchronously, a kernel-generated message
+ *			with an attached KDBUS_ITEM_REPLY_TIMEOUT item
+ *			is sent to @src_id. For synchronously executed send
+ *			command, the value denotes the maximum time the call
+ *			blocks to wait for a reply. The timeout is expected in
+ *			nanoseconds and as absolute CLOCK_MONOTONIC value.
+ * @cookie_reply:	A reply to the requesting message with the same
+ *			cookie. The requesting connection can match its
+ *			request and the reply with this value
+ * @items:		A list of kdbus_items containing the message payload
+ */
+struct kdbus_msg {
+	__u64 size;
+	__u64 flags;
+	__s64 priority;
+	__u64 dst_id;
+	__u64 src_id;
+	__u64 payload_type;
+	__u64 cookie;
+	union {
+		__u64 timeout_ns;
+		__u64 cookie_reply;
+	};
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_msg_info - returned message container
+ * @offset:		Offset of kdbus_msg slice in pool
+ * @msg_size:		Copy of the kdbus_msg.size field
+ * @return_flags:	Command return flags, kernel â userspace
+ */
+struct kdbus_msg_info {
+	__u64 offset;
+	__u64 msg_size;
+	__u64 return_flags;
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_send_flags - flags for sending messages
+ * @KDBUS_SEND_SYNC_REPLY:	Wait for destination connection to
+ *				reply to this message. The
+ *				KDBUS_CMD_SEND ioctl() will block
+ *				until the reply is received, and
+ *				offset_reply in struct kdbus_msg will
+ *				yield the offset in the sender's pool
+ *				where the reply can be found.
+ *				This flag is only valid if
+ *				@KDBUS_MSG_EXPECT_REPLY is set as well.
+ */
+enum kdbus_send_flags {
+	KDBUS_SEND_SYNC_REPLY		= 1ULL << 0,
+};
+
+/**
+ * struct kdbus_cmd_send - send message
+ * @size:		Overall size of this structure
+ * @flags:		Flags to change send behavior (KDBUS_SEND_*)
+ * @return_flags:	Command return flags, kernel â userspace
+ * @msg_address:	Storage address of the kdbus_msg to send
+ * @reply:		Storage for message reply if KDBUS_SEND_SYNC_REPLY
+ *			was given
+ * @items:		Additional items for this command
+ */
+struct kdbus_cmd_send {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__u64 msg_address;
+	struct kdbus_msg_info reply;
+	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		= 1ULL <<  0,
+	KDBUS_RECV_DROP		= 1ULL <<  1,
+	KDBUS_RECV_USE_PRIORITY	= 1ULL <<  2,
+};
+
+/**
+ * enum kdbus_recv_return_flags - return flags for message receive commands
+ * @KDBUS_RECV_RETURN_INCOMPLETE_FDS:	One or more file descriptors could not
+ *					be installed. These descriptors in
+ *					KDBUS_ITEM_FDS will carry the value -1.
+ * @KDBUS_RECV_RETURN_DROPPED_MSGS:	There have been dropped messages since
+ *					the last time a message was received.
+ *					The 'dropped_msgs' counter contains the
+ *					number of messages dropped pool
+ *					overflows or other missed broadcasts.
+ */
+enum kdbus_recv_return_flags {
+	KDBUS_RECV_RETURN_INCOMPLETE_FDS	= 1ULL <<  0,
+	KDBUS_RECV_RETURN_DROPPED_MSGS		= 1ULL <<  1,
+};
+
+/**
+ * struct kdbus_cmd_recv - struct to de-queue a buffered message
+ * @size:		Overall size of this object
+ * @flags:		KDBUS_RECV_* flags, userspace â kernel
+ * @return_flags:	Command return flags, kernel â userspace
+ * @priority:		Minimum priority of the messages to de-queue. Lowest
+ *			values have the highest priority.
+ * @dropped_msgs:	In case there were any dropped messages since the last
+ *			time a message was received, this will be set to the
+ *			number of lost messages and
+ *			KDBUS_RECV_RETURN_DROPPED_MSGS will be set in
+ *			'return_flags'. This can only happen if the ioctl
+ *			returns 0 or EAGAIN.
+ * @msg:		Return storage for received message.
+ * @items:		Additional items for this command.
+ *
+ * This struct is used with the KDBUS_CMD_RECV ioctl.
+ */
+struct kdbus_cmd_recv {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__s64 priority;
+	__u64 dropped_msgs;
+	struct kdbus_msg_info msg;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_cmd_free - struct to free a slice of memory in the pool
+ * @size:		Overall size of this structure
+ * @flags:		Flags for the free command, userspace â kernel
+ * @return_flags:	Command return flags, kernel â userspace
+ * @offset:		The offset of the memory slice, as returned by other
+ *			ioctls
+ * @items:		Additional items to modify the behavior
+ *
+ * This struct is used with the KDBUS_CMD_FREE ioctl.
+ */
+struct kdbus_cmd_free {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__u64 offset;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_hello_flags - flags for struct kdbus_cmd_hello
+ * @KDBUS_HELLO_ACCEPT_FD:	The connection allows the reception of
+ *				any passed file descriptors
+ * @KDBUS_HELLO_ACTIVATOR:	Special-purpose connection which registers
+ *				a well-know name for a process to be started
+ *				when traffic arrives
+ * @KDBUS_HELLO_POLICY_HOLDER:	Special-purpose connection which registers
+ *				policy entries for a name. The provided name
+ *				is not activated and not registered with the
+ *				name database, it only allows unprivileged
+ *				connections to acquire a name, talk or discover
+ *				a service
+ * @KDBUS_HELLO_MONITOR:	Special-purpose connection to monitor
+ *				bus traffic
+ */
+enum kdbus_hello_flags {
+	KDBUS_HELLO_ACCEPT_FD		=  1ULL <<  0,
+	KDBUS_HELLO_ACTIVATOR		=  1ULL <<  1,
+	KDBUS_HELLO_POLICY_HOLDER	=  1ULL <<  2,
+	KDBUS_HELLO_MONITOR		=  1ULL <<  3,
+};
+
+/**
+ * struct kdbus_cmd_hello - struct to say hello to kdbus
+ * @size:		The total size of the structure
+ * @flags:		Connection flags (KDBUS_HELLO_*), userspace â kernel
+ * @return_flags:	Command return flags, kernel â userspace
+ * @attach_flags_send:	Mask of metadata to attach to each message sent
+ *			off by this connection (KDBUS_ATTACH_*)
+ * @attach_flags_recv:	Mask of metadata to attach to each message receieved
+ *			by the new connection (KDBUS_ATTACH_*)
+ * @bus_flags:		The flags field copied verbatim from the original
+ *			KDBUS_CMD_BUS_MAKE ioctl. It's intended to be useful
+ *			to do negotiation of features of the payload that is
+ *			transferred (kernel â userspace)
+ * @id:			The ID of this connection (kernel â userspace)
+ * @pool_size:		Size of the connection's buffer where the received
+ *			messages are placed
+ * @offset:		Pool offset where items are returned to report
+ *			additional information about the bus and the newly
+ *			created connection.
+ * @items_size:		Size of buffer returned in the pool slice at @offset.
+ * @id128:		Unique 128-bit ID of the bus (kernel â userspace)
+ * @items:		A list of items
+ *
+ * This struct is used with the KDBUS_CMD_HELLO ioctl.
+ */
+struct kdbus_cmd_hello {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__u64 attach_flags_send;
+	__u64 attach_flags_recv;
+	__u64 bus_flags;
+	__u64 id;
+	__u64 pool_size;
+	__u64 offset;
+	__u64 items_size;
+	__u8 id128[16];
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_info - connection information
+ * @size:		total size of the struct
+ * @id:			64bit object ID
+ * @flags:		object creation flags
+ * @items:		list of items
+ *
+ * Note that the user is responsible for freeing the allocated memory with
+ * the KDBUS_CMD_FREE ioctl.
+ */
+struct kdbus_info {
+	__u64 size;
+	__u64 id;
+	__u64 flags;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_list_flags - what to include into the returned list
+ * @KDBUS_LIST_UNIQUE:		active connections
+ * @KDBUS_LIST_ACTIVATORS:	activator connections
+ * @KDBUS_LIST_NAMES:		known well-known names
+ * @KDBUS_LIST_QUEUED:		queued-up names
+ */
+enum kdbus_list_flags {
+	KDBUS_LIST_UNIQUE		= 1ULL <<  0,
+	KDBUS_LIST_NAMES		= 1ULL <<  1,
+	KDBUS_LIST_ACTIVATORS		= 1ULL <<  2,
+	KDBUS_LIST_QUEUED		= 1ULL <<  3,
+};
+
+/**
+ * struct kdbus_cmd_list - list connections
+ * @size:		overall size of this object
+ * @flags:		flags for the query (KDBUS_LIST_*), userspace â kernel
+ * @return_flags:	command return flags, kernel â userspace
+ * @offset:		Offset in the caller's pool buffer where an array of
+ *			kdbus_info objects is stored.
+ *			The user must use KDBUS_CMD_FREE to free the
+ *			allocated memory.
+ * @list_size:		size of returned list in bytes
+ * @items:		Items for the command. Reserved for future use.
+ *
+ * This structure is used with the KDBUS_CMD_LIST ioctl.
+ */
+struct kdbus_cmd_list {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__u64 offset;
+	__u64 list_size;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * struct kdbus_cmd_info - struct used for KDBUS_CMD_CONN_INFO ioctl
+ * @size:		The total size of the struct
+ * @flags:		Flags for this ioctl, userspace â kernel
+ * @return_flags:	Command return flags, kernel â userspace
+ * @id:			The 64-bit ID of the connection. If set to zero, passing
+ *			@name is required. kdbus will look up the name to
+ *			determine the ID in this case.
+ * @attach_flags:	Set of attach flags to specify the set of information
+ *			to receive, userspace â kernel
+ * @offset:		Returned offset in the caller's pool buffer where the
+ *			kdbus_info struct result is stored. The user must
+ *			use KDBUS_CMD_FREE to free the allocated memory.
+ * @info_size:		Output buffer to report size of data at @offset.
+ * @items:		The optional item list, containing the
+ *			well-known name to look up as a KDBUS_ITEM_NAME.
+ *			Only needed in case @id is zero.
+ *
+ * On success, the KDBUS_CMD_CONN_INFO ioctl will return 0 and @offset will
+ * tell the user the offset in the connection pool buffer at which to find the
+ * result in a struct kdbus_info.
+ */
+struct kdbus_cmd_info {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__u64 id;
+	__u64 attach_flags;
+	__u64 offset;
+	__u64 info_size;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_cmd_match_flags - flags to control the KDBUS_CMD_MATCH_ADD ioctl
+ * @KDBUS_MATCH_REPLACE:	If entries with the supplied cookie already
+ *				exists, remove them before installing the new
+ *				matches.
+ */
+enum kdbus_cmd_match_flags {
+	KDBUS_MATCH_REPLACE	= 1ULL <<  0,
+};
+
+/**
+ * struct kdbus_cmd_match - struct to add or remove matches
+ * @size:		The total size of the struct
+ * @flags:		Flags for match command (KDBUS_MATCH_*),
+ *			userspace â kernel
+ * @return_flags:	Command return flags, kernel â userspace
+ * @cookie:		Userspace supplied cookie. When removing, the cookie
+ *			identifies the match to remove
+ * @items:		A list of items for additional information
+ *
+ * This structure is used with the KDBUS_CMD_MATCH_ADD and
+ * KDBUS_CMD_MATCH_REMOVE ioctl.
+ */
+struct kdbus_cmd_match {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	__u64 cookie;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * enum kdbus_make_flags - Flags for KDBUS_CMD_{BUS,ENDPOINT}_MAKE
+ * @KDBUS_MAKE_ACCESS_GROUP:	Make the bus or endpoint node group-accessible
+ * @KDBUS_MAKE_ACCESS_WORLD:	Make the bus or endpoint node world-accessible
+ */
+enum kdbus_make_flags {
+	KDBUS_MAKE_ACCESS_GROUP		= 1ULL <<  0,
+	KDBUS_MAKE_ACCESS_WORLD		= 1ULL <<  1,
+};
+
+/**
+ * enum kdbus_name_flags - flags for KDBUS_CMD_NAME_ACQUIRE
+ * @KDBUS_NAME_REPLACE_EXISTING:	Try to replace name of other connections
+ * @KDBUS_NAME_ALLOW_REPLACEMENT:	Allow the replacement of the name
+ * @KDBUS_NAME_QUEUE:			Name should be queued if busy
+ * @KDBUS_NAME_IN_QUEUE:		Name is queued
+ * @KDBUS_NAME_ACTIVATOR:		Name is owned by a activator connection
+ */
+enum kdbus_name_flags {
+	KDBUS_NAME_REPLACE_EXISTING	= 1ULL <<  0,
+	KDBUS_NAME_ALLOW_REPLACEMENT	= 1ULL <<  1,
+	KDBUS_NAME_QUEUE		= 1ULL <<  2,
+	KDBUS_NAME_IN_QUEUE		= 1ULL <<  3,
+	KDBUS_NAME_ACTIVATOR		= 1ULL <<  4,
+};
+
+/**
+ * struct kdbus_cmd - generic ioctl payload
+ * @size:		Overall size of this structure
+ * @flags:		Flags for this ioctl, userspace â kernel
+ * @return_flags:	Ioctl return flags, kernel â userspace
+ * @items:		Additional items to modify the behavior
+ *
+ * This is a generic ioctl payload object. It's used by all ioctls that only
+ * take flags and items as input.
+ */
+struct kdbus_cmd {
+	__u64 size;
+	__u64 flags;
+	__u64 return_flags;
+	struct kdbus_item items[0];
+} __attribute__((__aligned__(8)));
+
+/**
+ * Ioctl API
+ *
+ * KDBUS_CMD_BUS_MAKE:		After opening the "control" node, this command
+ *				creates a new bus with the specified
+ *				name. The bus is immediately shut down and
+ *				cleaned up when the opened file descriptor is
+ *				closed.
+ *
+ * KDBUS_CMD_ENDPOINT_MAKE:	Creates a new named special endpoint to talk to
+ *				the bus. Such endpoints usually carry a more
+ *				restrictive policy and grant restricted access
+ *				to specific applications.
+ * KDBUS_CMD_ENDPOINT_UPDATE:	Update the properties of a custom enpoint. Used
+ *				to update the policy.
+ *
+ * KDBUS_CMD_HELLO:		By opening the bus node, a connection is
+ *				created. After a HELLO the opened connection
+ *				becomes an active peer on the bus.
+ * KDBUS_CMD_UPDATE:		Update the properties of a connection. Used to
+ *				update the metadata subscription mask and
+ *				policy.
+ * KDBUS_CMD_BYEBYE:		Disconnect a connection. If there are no
+ *				messages queued up in the connection's pool,
+ *				the call succeeds, and the handle is rendered
+ *				unusable. Otherwise, -EBUSY is returned without
+ *				any further side-effects.
+ * KDBUS_CMD_FREE:		Release the allocated memory in the receiver's
+ *				pool.
+ * KDBUS_CMD_CONN_INFO:		Retrieve credentials and properties of the
+ *				initial creator of the connection. The data was
+ *				stored at registration time and does not
+ *				necessarily represent the connected process or
+ *				the actual state of the process.
+ * KDBUS_CMD_BUS_CREATOR_INFO:	Retrieve information of the creator of the bus
+ *				a connection is attached to.
+ *
+ * KDBUS_CMD_SEND:		Send a message and pass data from userspace to
+ *				the kernel.
+ * KDBUS_CMD_RECV:		Receive a message from the kernel which is
+ *				placed in the receiver's pool.
+ *
+ * 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.
+ * KDBUS_CMD_NAME_RELEASE:	Release a well-known name the connection
+ *				currently owns.
+ * KDBUS_CMD_LIST:		Retrieve the list of all currently registered
+ *				well-known and unique names.
+ *
+ * KDBUS_CMD_MATCH_ADD:		Install a match which broadcast messages should
+ *				be delivered to the connection.
+ * KDBUS_CMD_MATCH_REMOVE:	Remove a current match for broadcast messages.
+ */
+enum kdbus_ioctl_type {
+	/* bus owner (00-0f) */
+	KDBUS_CMD_BUS_MAKE =		_IOW(KDBUS_IOCTL_MAGIC, 0x00,
+					     struct kdbus_cmd),
+
+	/* endpoint owner (10-1f) */
+	KDBUS_CMD_ENDPOINT_MAKE =	_IOW(KDBUS_IOCTL_MAGIC, 0x10,
+					     struct kdbus_cmd),
+	KDBUS_CMD_ENDPOINT_UPDATE =	_IOW(KDBUS_IOCTL_MAGIC, 0x11,
+					     struct kdbus_cmd),
+
+	/* connection owner (80-ff) */
+	KDBUS_CMD_HELLO =		_IOWR(KDBUS_IOCTL_MAGIC, 0x80,
+					      struct kdbus_cmd_hello),
+	KDBUS_CMD_UPDATE =		_IOW(KDBUS_IOCTL_MAGIC, 0x81,
+					     struct kdbus_cmd),
+	KDBUS_CMD_BYEBYE =		_IOW(KDBUS_IOCTL_MAGIC, 0x82,
+					     struct kdbus_cmd),
+	KDBUS_CMD_FREE =		_IOW(KDBUS_IOCTL_MAGIC, 0x83,
+					     struct kdbus_cmd_free),
+	KDBUS_CMD_CONN_INFO =		_IOR(KDBUS_IOCTL_MAGIC, 0x84,
+					     struct kdbus_cmd_info),
+	KDBUS_CMD_BUS_CREATOR_INFO =	_IOR(KDBUS_IOCTL_MAGIC, 0x85,
+					     struct kdbus_cmd_info),
+	KDBUS_CMD_LIST =		_IOR(KDBUS_IOCTL_MAGIC, 0x86,
+					     struct kdbus_cmd_list),
+
+	KDBUS_CMD_SEND =		_IOW(KDBUS_IOCTL_MAGIC, 0x90,
+					     struct kdbus_cmd_send),
+	KDBUS_CMD_RECV =		_IOR(KDBUS_IOCTL_MAGIC, 0x91,
+					     struct kdbus_cmd_recv),
+
+	KDBUS_CMD_NAME_ACQUIRE =	_IOW(KDBUS_IOCTL_MAGIC, 0xa0,
+					     struct kdbus_cmd),
+	KDBUS_CMD_NAME_RELEASE =	_IOW(KDBUS_IOCTL_MAGIC, 0xa1,
+					     struct kdbus_cmd),
+
+	KDBUS_CMD_MATCH_ADD =		_IOW(KDBUS_IOCTL_MAGIC, 0xb0,
+					     struct kdbus_cmd_match),
+	KDBUS_CMD_MATCH_REMOVE =	_IOW(KDBUS_IOCTL_MAGIC, 0xb1,
+					     struct kdbus_cmd_match),
+};
+
+#endif /* _KDBUS_UAPI_H_ */
-- 
2.3.1

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