ndet.h

操作系统SunOS 4.1.3版本的源码

/*	@(#)ndet.h 1.1 92/07/30 SMI	*/

/*
 * Copyright (c) 1985, 1988 by Sun Microsystems, Inc.
 */

/*
 * Ndet.h - Private header file for the detector part of the notifier.
 * The detector is responsible for noticing the occurrence of UNIX
 * events.  It maintains a complete list of clients that are awaiting
 * notification.  It maintains a per client list of conditions that the
 * client is awaiting.
 */

#ifndef	NDET_DEFINED
#define	NDET_DEFINED

#ifdef	COMMENT

********************** Detector Loop Notes ****************************
Here is some notes on the detector loop:

1) Any time that a notification changes (new, added, removed, modified),
the appropriate "changed" constant is ored into ndet_flags (see below). 
To determine the things that the notifier needs to ask UNIX
to watch for (fd activity, signals, itimers) requires scanning
all clients and notifications.  Comparing the result of this scan
with what the notifier is already watching for determines what work
has to be done to change what UNIX is doing.

2) A cycle of the notification loop can be entered in a variety of ways.

a) Notify_start can be called by the top level of the application.

b) When select is called, if notifications are being dispatched then
a real select system call is made.  Otherwise, a private notifier
client is generated that sets conditions equivalent to the select's
arguments.  Result bit masks and itimer expired flags are initialized.
Notify_start is then called.  If any of the select client's routines
are called, result bit masks and/or itimer expired flags are set.
In addition, notify_stop is called.  When notify_start returns, its
error code, errno, the result bit masks and/or itimer expired flags
are used to generate return values.

c) When read is called, if notifications are being dispatched then
a real read system call is made.  Otherwise, a private notifier
client is generated that sets an input pending condition for the read
fd.  A input pending flag is initialized.  Notify_start is then called.
If the read client's input pending routine is called, the input
pending flag is set.  In addition, notify_stop is called.  When
notify_stop returns, its error code, errno and the input pending flag
are used to figure out if a real read system call is to be done.
If so, a real read system call is done and the results returned.


********************** Public Interface Supporting *********************
The public programming interface that the detector supports follows:

notify_set_input_func
notify_set_output_func
notify_set_exception_func
notify_set_itimer_func
notify_set_signal_func
notify_set_wait3_func
notify_set_destroy_func
notify_set_event_func
notify_set_prioritizer_func

notify_get_itimer_value
notify_post_event
notify_post_destroy
notify_veto_destroy

notify_start
notify_stop
notify_die
notify_remove

fcntl
read
select

notify_get_input_func
notify_get_output_func
notify_get_exception_func
notify_get_itimer_func
notify_get_signal_func
notify_get_wait3_func
notify_get_destroy_func
notify_get_event_func
notify_get_prioritizer_func

#endif	COMMENT

/*
 * The detector uses ndet_/NDET_ name prefices.
 */

/*
 * Detector global data
 */
extern	u_int	ndet_flags;		/* Flags */
#define	NDET_STOP		0x01	/* Ntfy_stop called */
#define	NDET_FD_CHANGE		0x02	/* A fd condition changed */
#define	NDET_SIGNAL_CHANGE	0x04	/* A signal condition changed */
#define	NDET_REAL_CHANGE	0x08	/* A real itimer condition changed */
#define	NDET_VIRTUAL_CHANGE	0x10	/* A virtual itimer condition changed */
#define	NDET_WAIT3_CHANGE	0x20	/* A wait3 condition changed */
#define	NDET_DISPATCH		0x40	/* Calling ndis_dispatch (used to know
					   if should do real or notifier
					   version of read and select) */
#define	NDET_REAL_POLL		0x80	/* Real itimer wants to poll, invalid if
					   ndet_flags & NDET_REAL_CHANGE */
#define	NDET_VIRTUAL_POLL	0x100	/* Virtual itimer wants to poll, invalid
					   if ndet_flags & NDET_VIRTUAL_CHANGE*/
#define	NDET_POLL		(NDET_REAL_POLL|NDET_VIRTUAL_POLL)
					/* Do polling in select */
#define	NDET_INTERRUPT		0x200	/* Set when handling a signal interrupt
					   so that know not to go to system
					   heap */
#define	NDET_STARTED		0x400	/* In ntfy_start */
#define	NDET_EXIT_SOON		0x800	/* Notifier auto SIGTERM triggered,
					   exit(1) after finish dispatch */
#define	NDET_STOP_ON_SIG	0x1000	/* Notifier select client wants to break
					   if get a signal during real select */
#define	NDET_VETOED		0x2000	/* Notify_veto_destroy called */
#define	NDET_ITIMER_ENQ		0x4000	/* Itimer notification enqueued */
#define	NDET_NO_DELAY		0x8000	/* Caller of notify_start wants single
					   time around the loop */
#define	NDET_DESTROY_CHANGE	0x10000	/* A destroy condition changed */
#define	NDET_CONDITION_CHANGE	(NDET_FD_CHANGE|NDET_SIGNAL_CHANGE|\
    NDET_REAL_CHANGE|NDET_VIRTUAL_CHANGE|NDET_WAIT3_CHANGE|NDET_DESTROY_CHANGE)
					/* Combination of condition changes */

extern	NTFY_CLIENT *ndet_clients;	/* Active clients */
extern	NTFY_CLIENT *ndet_client_latest;/* Latest Notify_client=>NTFY_CLIENT
					   conversion success: for fast lookup
					   (nulled when client removed) */

extern	fd_set	ndet_fndelay_mask;	/* Mask of non-blocking read fds
					   (maintained by fcntl) */
extern	fd_set	ndet_fasync_mask;	/* Mask of fds that generate SIGIO
					   when data ready (maintained by
					   fcntl) */

extern	fd_set	ndet_ibits, ndet_obits, ndet_ebits;
					/* Select bit masks (invalid if
					   ndet_flags & NDET_FD_CHANGE) */
extern	struct	timeval ndet_polling_tv;/* Tv with select type polling value */

extern	u_int	ndet_sigs_auto;		/* Bits that indicate which signals the
					   notifier is automatically catching
					   (SIGIO, SIGURG, SIGCHLD, SIGTERM,
					   SIGALRM, SIGVTALRM) */
extern	void	ndet_toggle_auto();	/* When some condition that the notifier
					   is interested in changes, call this
					   to adjust ndet_sigs_auto (TBD reword)
					   (u_int obld_bits, sig) */
extern	Notify_value ndet_auto_sig_func();/* (Notify_client nclient,
					    int signal, Notify_signal_mode) */
extern	Notify_client ndet_auto_nclient;/* Private notifier client for auto
					   signal handling */
extern	NTFY_ENUM ndet_auto_sig_send();	/* Tell auto sig manager that one of
					   its condition has occurred
					   (NTFY_CLIENT *client,
					    NTFY_CONDITION *condition,
					    NTFY_ENUM_DATA context) */

extern	u_int	ndet_sigs_managing;	/* Signals that are managing (invalid if
					   ndet_flags & NDET_SIGNAL_CHANGE) */
extern	u_int	ndet_sigs_received;	/* Records signals received */
extern	void	ndet_enable_sig();	/* Call this routine (other than from
					   ndet_fig_sig_change) when you need
					   to make sure that a signal is being
					   caught but don't want to go through
					   the whole process of globally finding
					   out who else needs it. (u_int sig) */
extern	void	ndet_send_delayed_sigs();/* Process any async signal conditions
					   that have may have accumulated during
					   a critical section. */

extern	Notify_func ndet_set_fd_func();	/* (Notify_client nclient,
					    Notify_func func, int fd
					    NTFY_TYPE type) */
extern	Notify_func ndet_get_fd_func();	/* (Notify_client nclient,
					    int fd, NTFY_TYPE type) */
extern	Notify_func ndet_get_func();	/* (Notify_client nclient,
					    NTFY_TYPE type, NTFY_DATA data,
					    int use_data) */
extern	ndet_check_fd();		/* Returns 0 if all OK else -1 and
					   sets notify_errno to NOTIFY_BADF
					   (int fd) */