<dev/tty.h>

ttysvc protocol and client helpers.

ttysvc joins providers (UART and console drivers) to consumers (programs) through named endpoints. Each session, either kind, shares one page with ttysvc that holds two byte rings: up carries bytes from the session's owner to ttysvc, down carries bytes from ttysvc to the owner. For a driver, up is what was received and down is what to transmit; for a program, up is its output and down is its input.

A session's index is (generation << 8) | slot, so an index from a closed session never matches a reused slot. It is guessable, so any peer can close or re-mode another's session.

#include <dev/tty.h>

Types

Type	Definition	Description
TtyWatchRequest	TtyCloseRequest	TTY_WATCH request; same layout as TtyCloseRequest.
TtyFocusRequest	TtyCloseRequest	TTY_FOCUS request; same layout as TtyCloseRequest.

Constants

Name	Value	Description
TTY_NAME_MAX	16	Longest endpoint alias, including the NUL.
TTY_RING_DATA_SIZE	1024u	Bytes in each ring.
TTY_PROVIDE	1	Provide an endpoint (drivers). TtyConnectRequest; grants the session page. Replies TtyConnectReply and grants ttysvc's doorbell.
TTY_ATTACH	2	Attach to an endpoint (programs). Same request and reply as TTY_PROVIDE.
TTY_NOTIFY	3	Give ttysvc the caller's event. TtyNotifyRequest; grants the event.
TTY_SETMODE	4	Set a consumer's mode. TtySetModeRequest.
TTY_CLOSE	5	End a session. TtyCloseRequest.
TTY_WATCH	6	Tie a session to the caller's life. TtyWatchRequest; grants a port the caller owns (PERM_WAIT | PERM_TXFR). ttysvc closes the session when that port dies.
TTY_FOCUS	7	Take the endpoint's input (consumers). TtyFocusRequest.
TTY_MODE_RAW	0u	Mode: bytes pass through untouched. The default.
TTY_MODE_COOKED	(1u << 0)	Mode: line editing (^H, DEL, ^U, ^W), input delivered a line at a time, ^D signals EOF and ^C an interrupt; ' ' becomes "\r\n" on output.
TTY_MODE_ECHO	(1u << 1)	Mode: ttysvc echoes typed characters.
TTY_MODE_ALL	(TTY_MODE_COOKED \| TTY_MODE_ECHO)	Every mode flag.

Structures

TtyCtl

Out-of-band signals from ttysvc to a consumer.

Field	Type	Description
eof_seq	volatile uint32_t	Bumped by ttysvc for each ^D in cooked mode.
eof_ack	volatile uint32_t	Last eof_seq the consumer has handled.
eof_pos	volatile uint32_t	down ring position the EOF applies at.
intr_seq	volatile uint32_t	Bumped by ttysvc for each ^C in cooked mode.

TtyShm

The page a session shares with ttysvc.

Field	Type	Description
up_hdr	ShmRingHdr	Owner to ttysvc ring.
up_data	uint8_t	Its data.
down_hdr	ShmRingHdr	ttysvc to owner ring.
down_data	uint8_t	Its data.
ctl	TtyCtl	EOF and interrupt signals.

TtyConnectRequest

TTY_PROVIDE and TTY_ATTACH request.

Field	Type	Description
cmd	uint32_t	TTY_PROVIDE or TTY_ATTACH.
alias	char	Endpoint name; empty attaches to the default endpoint.

TtyNotifyRequest

TTY_NOTIFY request.

Field	Type	Description
cmd	uint32_t	TTY_NOTIFY.
index	uint32_t	Session index.
bit	uint32_t	Bit ttysvc rings on the caller's event.

TtySetModeRequest

TTY_SETMODE request.

Field	Type	Description
cmd	uint32_t	TTY_SETMODE.
index	uint32_t	Session index.
flags	uint32_t	TTY_MODE_* flags.

TtyCloseRequest

TTY_CLOSE request.

Field	Type	Description
cmd	uint32_t	The command.
index	uint32_t	Session index.

TtyConnectReply

TTY_PROVIDE and TTY_ATTACH reply.

Field	Type	Description
status	Err	ZUZU_OK, or an error code.
bit	uint32_t	Bit to ring on ttysvc's doorbell.
index	uint32_t	Session index for later requests.

TtyConn

A session with ttysvc, for providers and consumers alike.

Field	Type	Description
shm	TtyShm *	Mapped session page.
mem	Handle	The session page's memory object.
doorbell	Handle	ttysvc's event, send-only.
bit	uint32_t	Bit to ring on doorbell.
index	uint32_t	Session index.
live	Handle	Port this client owns; ttysvc watches it to notice the client's death.