A PTY (pseudoterminal) emulates terminal devices, with a "server" side (which represents the keyboard+monitor side of the terminal and is obtained by opening /dev/misc/ptmx) and a number of "client" sides which are obtained by calling OpenClient.

Client PTYs are identified by the id used in the OpenClient call. The first Client PTY must be 0, and it is the only Client PTY that is allowed to create additional Client PTYs, receive Events, etc. It is the Controlling PTY.

PROTOCOLS

Device

Defined in fuchsia.hardware.pty/pty.fidl

AdvisoryLock

Acquires an advisory lock on the underlying file.

The lock lasts until either this connection is closed or this method is called with |AdvisoryLockType.UNLOCK| to release the lock explicitly.

Advisory locks are purely advisory. They do not prevent actual read or write operations from occurring on the file, either through this connection or through other connections.

This method requires the following rights:

• Rights.READ_BYTES if request.type is AdvisoryLockType.READ.
• Rights.WRITE_BYTES if request.type is AdvisoryLockType.WRITE.

Errors

• ZX_ERR_BAD_STATE The specified type of lock cannot be acquired. For example, another connection might hold a conflicting lock type.
• ZX_ERR_NOT_SUPPORTED This file does not support advisory locking.
• ZX_ERR_ACCESS_DENIED This connection does not have sufficient rights to acquire the given type of lock.

Request

Name	Type
request	fuchsia.io2/AdvisoryLockRequest

Response

Name	Type
result	fuchsia.io2/AdvisoryLocking_AdvisoryLock_Result

Clone

Create another connection to the same remote object.

flags may be any of:

• OPEN_RIGHT_*
• OPEN_FLAG_APPEND
• OPEN_FLAG_NO_REMOTE
• OPEN_FLAG_DESCRIBE
• CLONE_FLAG_SAME_RIGHTS

All other flags are ignored.

The OPEN_RIGHT_* bits in flags request corresponding rights over the resulting cloned object. The cloned object must have rights less than or equal to the original object. Alternatively, pass CLONE_FLAG_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OPEN_RIGHT_* flags together with CLONE_FLAG_SAME_RIGHTS.

Request

Name	Type
flags	uint32
object	request<fuchsia.io/Node>

Close

Terminates connection with object.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
s	zx/status

ClrSetFeature

allowed on Client PTYs

Clear and/or Set PTY Features

Request

Name	Type
clr	uint32
set	uint32

Response

Name	Type
status	zx/status
features	uint32

Describe

Returns extra information about the type of the object. If the Describe operation fails, the connection is closed.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
info	fuchsia.io/NodeInfo

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
s	zx/status
attributes	fuchsia.io/NodeAttributes

GetBuffer

Acquires a buffer representing this file, if there is one, with the requested access rights.

flags may be any of VMO_FLAG_*.

This method requires following rights:

• OPEN_RIGHT_WRITABLE if flags includes VMO_FLAG_WRITE.
• OPEN_RIGHT_READABLE if flags includes VMO_FLAG_READ or VMO_FLAG_EXEC.

Request

Name	Type
flags	uint32

Response

Name	Type
s	zx/status
buffer	fuchsia.mem/Buffer?

GetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
s	zx/status
flags	uint32

GetWindowSize

Obtain the window size (in character cells)

Request

Name	Type

Response

Name	Type
status	zx/status
size	WindowSize

MakeActive

allowed on the Controlling PTY

Select which Client PTY receives input. Reads will simply block on non-active PTYs.

Request

Name	Type
client_pty_id	uint32

Response

Name	Type
status	zx/status

NodeGetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights. This method has the same functionality as GetFlags for File and is meant as an in-progress replacement.

Request

Name	Type

Response

Name	Type
s	zx/status
flags	uint32

NodeSetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OPEN_FLAG_APPEND

This method does not require any rights. This method has the same functionality as SetFlags for File and is meant as an in-progress replacement.

Request

Name	Type
flags	uint32

Response

Name	Type
s	zx/status

OnOpen

An event produced eagerly by a FIDL server if requested by OPEN_FLAG_DESCRIBE.

Indicates the success or failure of the open operation, and optionally describes the object. If the status is ZX_OK, info contains descriptive information about the object (the same as would be returned by Describe).

Response

Name	Type
s	zx/status
info	fuchsia.io/NodeInfo?

OpenClient

Open a client PTY device with a unique id. client should be a handle to one endpoint of a channel that (on success) will become an open connection to the newly created device. On failure, the channel will be closed. Closing the channel will close the connection and release the device. If the provided id is 0, then the new client is a controlling client and has the capability to open additional clients. If the current device is not a controlling client, ZX_ERR_ACCESS_DENIED will be returned. If id is not unique, ZX_ERR_INVALID_ARGS will be returned. Otherwise the status code from device_add is passed on.

Request

Name	Type
id	uint32
client	handle<channel>

Response

Name	Type
s	zx/status

Read

Reads count bytes at the seek offset. The seek offset is moved forward by the number of bytes read.

This method requires following rights: OPEN_RIGHT_READABLE.

Request

Name	Type
count	uint64

Response

Name	Type
s	zx/status
data	vector<uint8>[8192]

ReadAt

Reads count bytes at the provided offset. Does not affect the seek offset.

This method requires following rights: OPEN_RIGHT_READABLE.

Request

Name	Type
count	uint64
offset	uint64

Response

Name	Type
s	zx/status
data	vector<uint8>[8192]

ReadEvents

Returns pending OOB events, simultaneously clearing them

Request

Name	Type

Response

Name	Type
status	zx/status
events	uint32

Seek

Moves the offset at which the next invocation of Read() or Write() will occur.

This method does not require any rights.

Request

Name	Type
offset	int64
start	fuchsia.io/SeekOrigin

Response

Name	Type
s	zx/status
offset	uint64

SetAttr

Updates information about the node. flags may be any of NODE_ATTRIBUTE_FLAG_*.

This method requires following rights: OPEN_RIGHT_WRITABLE.

Request

Name	Type
flags	uint32
attributes	fuchsia.io/NodeAttributes

Response

Name	Type
s	zx/status

SetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OPEN_FLAG_APPEND

This method does not require any rights.

Request

Name	Type
flags	uint32

Response

Name	Type
s	zx/status

SetWindowSize

allowed on the Server PTY

Sets the window size

Request

Name	Type
size	WindowSize

Response

Name	Type
status	zx/status

Sync

Synchronizes updates to the node to the underlying media, if it exists.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
s	zx/status

Truncate

Shrinks the file size to 'length' bytes.

This method requires following rights: OPEN_RIGHT_WRITABLE.

Request

Name	Type
length	uint64

Response

Name	Type
s	zx/status

Write

Writes data at the seek offset. The seek offset is moved forward by the number of bytes written.

This method requires following rights: OPEN_RIGHT_WRITABLE.

Request

Name	Type
data	vector<uint8>[8192]

Response

Name	Type
s	zx/status
actual	uint64

WriteAt

Writes data to the provided offset. Does not affect the seek offset.

This method requires following rights: OPEN_RIGHT_WRITABLE.

Request

Name	Type
data	vector<uint8>[8192]
offset	uint64

Response

Name	Type
s	zx/status
actual	uint64

STRUCTS

WindowSize

Defined in fuchsia.hardware.pty/pty.fidl

Name	Type	Description	Default
width	uint32		No default
height	uint32		No default

CONSTANTS

Name	Value	Type	Description
EVENT_HANGUP	1	uint32	The terminal has no active client.
EVENT_INTERRUPT	2	uint32	The terminal received a ^C control character.
EVENT_MASK	7	uint32	All events
EVENT_SUSPEND	4	uint32	The terminal received a ^Z control character.
FEATURE_RAW	1	uint32	When Feature Raw is enabled, OOB Events like ^c, ^z, etc are not generated. Instead the character is read from the read() input path.
SIGNAL_EVENT	33554432	uint32	When an event is pending, this signal is asserted on the Controlling PTY.