3 * I/O multiplexing support
5 * (c) 1999 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the mLib utilities library.
12 * mLib is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * mLib is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with mLib; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 /*----- Header files ------------------------------------------------------*/
35 #include <sys/types.h>
43 /*----- Data structures ---------------------------------------------------*/
45 typedef struct sel_pendfile
{
46 struct sel_pendfile
*next
;
50 typedef struct sel_pendtimer
{
51 struct sel_pendtimer
*next
;
55 /*----- Main code ---------------------------------------------------------*/
57 /* --- @sel_init@ --- *
59 * Arguments: @sel_state *s@ = pointer to a state block to initialize
63 * Use: Initializes a select state block.
66 void sel_init(sel_state
*s
)
70 for (i
= 0; i
< SEL_MODES
; i
++) {
79 /* --- @sel_initfile@ --- *
81 * Arguments: @sel_state *s@ = select state to attach to
82 * @sel_file *f@ = pointer to a file block to initialize
83 * @int fd@ = the file descriptor to listen to
84 * @unsigned mode@ = what to listen for
85 * @void (*func)(int fd, unsigned mode, void *p)@ = handler
86 * @void *p@ = argument to pass to handler
90 * Use: Initializes a file block ready for use. The file block
91 * isn't added to the list of things to do until a call to
95 void sel_initfile(sel_state
*s
, sel_file
*f
,
96 int fd
, unsigned mode
,
97 void (*func
)(int /*fd*/, unsigned /*mode*/, void */
*p*/
),
108 /* --- @sel_addfile@ --- *
110 * Arguments: @sel_file *f@ = pointer to a file block
114 * Use: Adds a file block into the list of things to listen to.
117 void sel_addfile(sel_file
*f
)
119 sel_file
**ff
= &f
->s
->files
[f
->mode
];
121 /* --- This little dance looks like line-noise, but it does the job --- */
123 while (*ff
&& (*ff
)->fd
> f
->fd
)
128 (*ff
)->prev
= &f
->next
;
130 FD_SET(f
->fd
, f
->s
->fd
+ f
->mode
);
133 /* --- @sel_force@ --- *
135 * Arguments: @sel_file *f@ = pointer to file selector
139 * Use: Forces a file selector to be considered ready. This is only
140 * useful during a call to @sel_select@. Of particular use is
141 * forcing a write selector when there's something interesting
145 void sel_force(sel_file
*f
)
148 FD_SET(f
->fd
, &f
->s
->args
->fd
[f
->mode
]);
151 /* --- @sel_rmfile@ --- *
153 * Arguments: @sel_file *f@ = pointer to a file block
157 * Use: Removes a file block from the list of things to listen to.
160 void sel_rmfile(sel_file
*f
)
164 f
->next
->prev
= f
->prev
;
165 FD_CLR(f
->fd
, f
->s
->fd
+ f
->mode
);
172 /* --- @sel_addtimer@ --- *
174 * Arguments: @sel_state *s@ = pointer to a state block
175 * @sel_timer *t@ = pointer to a timer block
176 * @struct timeval *tv@ = pointer to time to activate
177 * @void (*func)(struct timeval *tv, void *p)@ = handler
178 * @void *p@ = argument for handler function
182 * Use: Registers and sets up a timer.
185 void sel_addtimer(sel_state
*s
, sel_timer
*t
,
187 void (*func
)(struct timeval */
*tv*/
, void */
*p*/
),
190 sel_timer
**tt
= &s
->timers
;
191 { sel_timer
*q
; for (q
= s
->timers
; q
; q
= q
->next
) assert(q
!= t
); }
193 /* --- Set up the timer block --- */
200 /* --- More line noise --- */
202 while (*tt
&& TV_CMP(&(*tt
)->tv
, <, tv
))
207 (*tt
)->prev
= &t
->next
;
211 /* --- @sel_rmtimer@ --- *
213 * Arguments: @sel_timer *t@ = pointer to timer block
217 * Use: Removes a timer from the list of timers.
220 void sel_rmtimer(sel_timer
*t
)
228 t
->next
->prev
= t
->prev
;
232 /* --- @sel_addhook@ --- *
234 * Arguments: @sel_state *s@ = pointer to state block
235 * @sel_hook *h@ = pointer to hook block
236 * @sel_hookfn before, after@ = hook functions
237 * @void *p@ = pointer argument to pass to hook functions
241 * Use: Registers hook functions to be called on each select call.
244 void sel_addhook(sel_state
*s
, sel_hook
*h
,
245 sel_hookfn before
, sel_hookfn after
,
254 s
->hooks
->prev
= &h
->next
;
258 /* --- @sel_rmhook@ --- *
260 * Arguments: @sel_hook *h@ = pointer to hook block
264 * Use: Removes hook functions.
267 void sel_rmhook(sel_hook
*h
)
270 h
->next
->prev
= h
->prev
;
274 /* --- @sel_fdmerge@ --- *
276 * Arguments: @fd_set *dest@ = destination FD set
277 * @fd_set *fd@ = pointer to set to merge
278 * @int maxfd@ = highest numbered descriptor in @fd@ + 1
280 * Returns: Actual highest numbered descriptor.
282 * Use: Merges file descriptor sets, and returns an accurate @maxfd@
286 int sel_fdmerge(fd_set
*dest
, fd_set
*fd
, int maxfd
)
290 for (i
= 0; i
< maxfd
; i
++) {
291 if (FD_ISSET(i
, fd
)) {
300 /* --- @sel_select@ --- *
302 * Arguments: @sel_state *s@ = pointer to state block
304 * Returns: Zero if all OK, -1 on error.
306 * Use: Does a @select@ call (or equivalent @poll@).
309 int sel_select(sel_state
*s
)
314 /* --- Initialize the argument block --- */
319 for (i
= 0; i
< SEL_MODES
; i
++) {
320 if (s
->files
[i
] && s
->files
[i
]->fd
>= a
.maxfd
)
321 a
.maxfd
= s
->files
[i
]->fd
+ 1;
325 memcpy(a
.fd
, s
->fd
, sizeof(a
.fd
));
326 if (s
->timers
|| s
->hooks
)
327 gettimeofday(&a
.now
, 0);
331 if (TV_CMP(&s
->timers
->tv
, >, &a
.now
))
332 TV_SUB(&a
.tv
, &s
->timers
->tv
, &a
.now
);
341 /* --- Grind through the pre hooks --- */
344 sel_hook
*h
= s
->hooks
;
349 hh
->before(s
, &a
, hh
->p
);
353 /* --- Run the @select@ call --- */
355 if ((err
= select(a
.maxfd
,
356 &a
.fd
[SEL_READ
], &a
.fd
[SEL_WRITE
], &a
.fd
[SEL_EXC
],
363 gettimeofday(&a
.now
, 0);
365 /* --- Run through the hooks again --- */
368 sel_hook
*h
= s
->hooks
;
373 hh
->after(s
, &a
, hh
->p
);
377 /* --- Run through the timers --- */
380 ptimer
*pthead
, *pt
, **ptt
= &pthead
;
383 for (t
= s
->timers
; t
&& TV_CMP(&t
->tv
, <=, &a
.now
); t
= t
->next
) {
393 t
->prev
= &s
->timers
;
404 t
->func(&a
.now
, t
->p
);
410 /* --- And finally run through the files --- *
412 * Do reads first. It's quite possible that a read might prompt a write,
413 * but the other way around is less likely. Fortunately, the modes are
414 * in the right order for this.
420 for (i
= 0; i
< SEL_MODES
; i
++) {
421 pfile
*pfhead
, *pf
, **pff
= &pfhead
;
424 for (f
= s
->files
[i
]; f
; f
= f
->next
) {
425 if (!FD_ISSET(f
->fd
, &a
.fd
[i
]))
440 f
->func(f
->fd
, i
, f
->p
);
451 /*----- That's all, folks -------------------------------------------------*/