3 * $Id: sel.c,v 1.3 1999/05/21 22:13:59 mdw Exp $
5 * I/O multiplexing support
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * mLib is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 1999/05/21 22:13:59 mdw
34 * Use new `tv' macros. Fix ordering bug for timeout selectors.
36 * Revision 1.2 1999/05/15 10:33:32 mdw
37 * Fix copyright notices.
39 * Revision 1.1 1999/05/14 21:01:14 mdw
40 * Integrated `select' handling bits from the background resolver project.
44 /*----- Header files ------------------------------------------------------*/
50 #include <sys/types.h>
57 /*----- Main code ---------------------------------------------------------*/
59 /* --- @sel_init@ --- *
61 * Arguments: @sel_state *s@ = pointer to a state block to initialize
65 * Use: Initializes a select state block.
68 void sel_init(sel_state
*s
)
72 FD_ZERO(&s
->fd
[SEL_READ
]);
73 FD_ZERO(&s
->fd
[SEL_WRITE
]);
74 FD_ZERO(&s
->fd
[SEL_EXC
]);
77 /* --- @sel_initfile@ --- *
79 * Arguments: @sel_state *s@ = select state to attach to
80 * @sel_file *f@ = pointer to a file block to initialize
81 * @int fd@ = the file descriptor to listen to
82 * @unsigned mode@ = what to listen for
83 * @void (*func)(int fd, unsigned mode, void *p)@ = handler
84 * @void *p@ = argument to pass to handler
88 * Use: Initializes a file block ready for use. The file block
89 * isn't added to the list of things to do until a call to
93 void sel_initfile(sel_state
*s
, sel_file
*f
,
94 int fd
, unsigned mode
,
95 void (*func
)(int /*fd*/, unsigned /*mode*/, void */
*p*/
),
105 /* --- @sel_addfile@ --- *
107 * Arguments: @sel_file *f@ = pointer to a file block
111 * Use: Adds a file block into the list of things to listen to.
114 void sel_addfile(sel_file
*f
)
116 sel_file
**ff
= &f
->s
->files
;
118 /* --- This little dance looks like line-noise, but it does the job --- */
120 while (*ff
&& (*ff
)->fd
> f
->fd
)
123 f
->prev
= (sel_file
*)ff
;
127 FD_SET(f
->fd
, f
->s
->fd
+ f
->mode
);
130 /* --- @sel_rmfile@ --- *
132 * Arguments: @sel_file *f@ = pointer to a file block
136 * Use: Removes a file block from the list of things to listen to.
139 void sel_rmfile(sel_file
*f
)
141 f
->prev
->next
= f
->next
;
143 f
->next
->prev
= f
->prev
;
144 FD_CLR(f
->fd
, f
->s
->fd
+ f
->mode
);
147 /* --- @sel_addtimer@ --- *
149 * Arguments: @sel_state *s@ = pointer to a state block
150 * @sel_timer *t@ = pointer to a timer block
151 * @struct timeval *tv@ = pointer to time to activate
152 * @void (*func)(struct timeval *tv, void *p)@ = handler
153 * @void *p@ = argument for handler function
157 * Use: Registers and sets up a timer.
160 void sel_addtimer(sel_state
*s
, sel_timer
*t
,
162 void (*func
)(struct timeval */
*tv*/
, void */
*p*/
),
165 sel_timer
**tt
= &s
->timers
;
167 /* --- Set up the timer block --- */
173 /* --- More line noise --- */
175 while (*tt
&& TV_CMP(&(*tt
)->tv
, <, tv
))
178 t
->prev
= (sel_timer
*)tt
;
184 /* --- @sel_rmtimer@ --- *
186 * Arguments: @sel_timer *t@ = pointer to timer block
190 * Use: Removes a timer from the list of timers.
193 void sel_rmtimer(sel_timer
*t
)
195 t
->prev
->next
= t
->next
;
197 t
->next
->prev
= t
->prev
;
200 /* --- @sel_select@ --- *
202 * Arguments: @sel_state *s@ = pointer to state block
204 * Returns: Zero if all OK, -1 on error.
206 * Use: Does a @select@ call (or equivalent @poll@).
209 int sel_select(sel_state
*s
)
211 fd_set fd
[SEL_MODES
];
215 memcpy(fd
, s
->fd
, sizeof(s
->fd
));
218 gettimeofday(&now
, 0);
219 TV_SUB(&tv
, &s
->timers
->tv
, &now
);
220 err
= select(s
->files ? s
->files
->fd
+ 1 : 0,
221 fd
+ SEL_READ
, fd
+ SEL_WRITE
, fd
+ SEL_EXC
,
223 gettimeofday(&tv
, 0);
225 err
= select(s
->files ? s
->files
->fd
+ 1 : 0,
226 fd
+ SEL_READ
, fd
+ SEL_WRITE
, fd
+ SEL_EXC
,
234 for (t
= s
->timers
; t
&& TV_CMP(&t
->tv
, <=, &tv
); t
= tt
) {
236 t
->next
= t
->prev
= t
;
241 t
->prev
= (sel_timer
*)&s
->timers
;
246 for (f
= s
->files
; f
; f
= ff
) {
248 if (FD_ISSET(f
->fd
, fd
+ f
->mode
))
249 f
->func(f
->fd
, f
->mode
, f
->p
);
256 /*----- That's all, folks -------------------------------------------------*/