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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: sel.c,v 1.4 1999/08/19 18:30:26 mdw Exp $ |
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4 | * |
5 | * I/O multiplexing support |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
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. |
18 | * |
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. |
23 | * |
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, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: sel.c,v $ |
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33 | * Revision 1.4 1999/08/19 18:30:26 mdw |
34 | * Implement hooks for foreign select-using systems (currently not well |
35 | * tested). |
36 | * |
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37 | * Revision 1.3 1999/05/21 22:13:59 mdw |
38 | * Use new `tv' macros. Fix ordering bug for timeout selectors. |
39 | * |
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40 | * Revision 1.2 1999/05/15 10:33:32 mdw |
41 | * Fix copyright notices. |
42 | * |
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43 | * Revision 1.1 1999/05/14 21:01:14 mdw |
44 | * Integrated `select' handling bits from the background resolver project. |
45 | * |
46 | */ |
47 | |
48 | /*----- Header files ------------------------------------------------------*/ |
49 | |
50 | #include <stdio.h> |
51 | #include <stdlib.h> |
52 | #include <string.h> |
53 | |
54 | #include <sys/types.h> |
55 | #include <sys/time.h> |
56 | #include <unistd.h> |
57 | |
58 | #include "sel.h" |
59 | #include "tv.h" |
60 | |
61 | /*----- Main code ---------------------------------------------------------*/ |
62 | |
63 | /* --- @sel_init@ --- * |
64 | * |
65 | * Arguments: @sel_state *s@ = pointer to a state block to initialize |
66 | * |
67 | * Returns: --- |
68 | * |
69 | * Use: Initializes a select state block. |
70 | */ |
71 | |
72 | void sel_init(sel_state *s) |
73 | { |
74 | s->files = 0; |
75 | s->timers = 0; |
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76 | s->hooks = 0; |
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77 | FD_ZERO(&s->fd[SEL_READ]); |
78 | FD_ZERO(&s->fd[SEL_WRITE]); |
79 | FD_ZERO(&s->fd[SEL_EXC]); |
80 | } |
81 | |
82 | /* --- @sel_initfile@ --- * |
83 | * |
84 | * Arguments: @sel_state *s@ = select state to attach to |
85 | * @sel_file *f@ = pointer to a file block to initialize |
86 | * @int fd@ = the file descriptor to listen to |
87 | * @unsigned mode@ = what to listen for |
88 | * @void (*func)(int fd, unsigned mode, void *p)@ = handler |
89 | * @void *p@ = argument to pass to handler |
90 | * |
91 | * Returns: --- |
92 | * |
93 | * Use: Initializes a file block ready for use. The file block |
94 | * isn't added to the list of things to do until a call to |
95 | * @sel_addfile@. |
96 | */ |
97 | |
98 | void sel_initfile(sel_state *s, sel_file *f, |
99 | int fd, unsigned mode, |
100 | void (*func)(int /*fd*/, unsigned /*mode*/, void */*p*/), |
101 | void *p) |
102 | { |
103 | f->s = s; |
104 | f->fd = fd; |
105 | f->mode = mode; |
106 | f->func = func; |
107 | f->p = p; |
108 | } |
109 | |
110 | /* --- @sel_addfile@ --- * |
111 | * |
112 | * Arguments: @sel_file *f@ = pointer to a file block |
113 | * |
114 | * Returns: --- |
115 | * |
116 | * Use: Adds a file block into the list of things to listen to. |
117 | */ |
118 | |
119 | void sel_addfile(sel_file *f) |
120 | { |
121 | sel_file **ff = &f->s->files; |
122 | |
123 | /* --- This little dance looks like line-noise, but it does the job --- */ |
124 | |
125 | while (*ff && (*ff)->fd > f->fd) |
126 | ff = &(*ff)->next; |
127 | f->next = *ff; |
128 | f->prev = (sel_file *)ff; |
129 | if (*ff) |
130 | (*ff)->prev = f; |
131 | *ff = f; |
132 | FD_SET(f->fd, f->s->fd + f->mode); |
133 | } |
134 | |
135 | /* --- @sel_rmfile@ --- * |
136 | * |
137 | * Arguments: @sel_file *f@ = pointer to a file block |
138 | * |
139 | * Returns: --- |
140 | * |
141 | * Use: Removes a file block from the list of things to listen to. |
142 | */ |
143 | |
144 | void sel_rmfile(sel_file *f) |
145 | { |
146 | f->prev->next = f->next; |
147 | if (f->next) |
148 | f->next->prev = f->prev; |
149 | FD_CLR(f->fd, f->s->fd + f->mode); |
150 | } |
151 | |
152 | /* --- @sel_addtimer@ --- * |
153 | * |
154 | * Arguments: @sel_state *s@ = pointer to a state block |
155 | * @sel_timer *t@ = pointer to a timer block |
156 | * @struct timeval *tv@ = pointer to time to activate |
157 | * @void (*func)(struct timeval *tv, void *p)@ = handler |
158 | * @void *p@ = argument for handler function |
159 | * |
160 | * Returns: --- |
161 | * |
162 | * Use: Registers and sets up a timer. |
163 | */ |
164 | |
165 | void sel_addtimer(sel_state *s, sel_timer *t, |
166 | struct timeval *tv, |
167 | void (*func)(struct timeval */*tv*/, void */*p*/), |
168 | void *p) |
169 | { |
170 | sel_timer **tt = &s->timers; |
171 | |
172 | /* --- Set up the timer block --- */ |
173 | |
174 | t->tv = *tv; |
175 | t->func = func; |
176 | t->p = p; |
177 | |
178 | /* --- More line noise --- */ |
179 | |
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180 | while (*tt && TV_CMP(&(*tt)->tv, <, tv)) |
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181 | tt = &(*tt)->next; |
182 | t->next = *tt; |
183 | t->prev = (sel_timer *)tt; |
184 | if (*tt) |
185 | (*tt)->prev = t; |
186 | *tt = t; |
187 | } |
188 | |
189 | /* --- @sel_rmtimer@ --- * |
190 | * |
191 | * Arguments: @sel_timer *t@ = pointer to timer block |
192 | * |
193 | * Returns: --- |
194 | * |
195 | * Use: Removes a timer from the list of timers. |
196 | */ |
197 | |
198 | void sel_rmtimer(sel_timer *t) |
199 | { |
200 | t->prev->next = t->next; |
201 | if (t->next) |
202 | t->next->prev = t->prev; |
203 | } |
204 | |
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205 | /* --- @sel_addhook@ --- * |
206 | * |
207 | * Arguments: @sel_state *s@ = pointer to state block |
208 | * @sel_hook *h@ = pointer to hook block |
209 | * @sel_hookfn before, after@ = hook functions |
210 | * @void *p@ = pointer argument to pass to hook functions |
211 | * |
212 | * Returns: --- |
213 | * |
214 | * Use: Registers hook functions to be called on each select call. |
215 | */ |
216 | |
217 | void sel_addhook(sel_state *s, sel_hook *h, |
218 | sel_hookfn before, sel_hookfn after, |
219 | void *p) |
220 | { |
221 | h->before = before; |
222 | h->after = after; |
223 | h->p = p; |
224 | h->next = s->hooks; |
225 | h->prev = (sel_hook *)&s->hooks; |
226 | if (s->hooks) |
227 | s->hooks->prev = h; |
228 | s->hooks = h; |
229 | } |
230 | |
231 | /* --- @sel_rmhook@ --- * |
232 | * |
233 | * Arguments: @sel_hook *h@ = pointer to hook block |
234 | * |
235 | * Returns: --- |
236 | * |
237 | * Use: Removes hook functions. |
238 | */ |
239 | |
240 | void sel_rmhook(sel_hook *h) |
241 | { |
242 | if (h->next) |
243 | h->next->prev = h->prev; |
244 | h->prev->next = h->next; |
245 | } |
246 | |
247 | /* --- @sel_fdmerge@ --- * |
248 | * |
249 | * Arguments: @fd_set *dest@ = destination FD set |
250 | * @fd_set *fd@ = pointer to set to merge |
251 | * @int maxfd@ = highest numbered descriptor in @fd@ + 1 |
252 | * |
253 | * Returns: Actual highest numbered descriptor. |
254 | * |
255 | * Use: Merges file descriptor sets, and returns an accurate @maxfd@ |
256 | * value. |
257 | */ |
258 | |
259 | int sel_fdmerge(fd_set *dest, fd_set *fd, int maxfd) |
260 | { |
261 | int i, m = -1; |
262 | |
263 | for (i = 0; i < maxfd; i++) { |
264 | if (FD_ISSET(i, fd)) { |
265 | FD_SET(i, dest); |
266 | m = i; |
267 | } |
268 | } |
269 | |
270 | return (m + 1); |
271 | } |
272 | |
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273 | /* --- @sel_select@ --- * |
274 | * |
275 | * Arguments: @sel_state *s@ = pointer to state block |
276 | * |
277 | * Returns: Zero if all OK, -1 on error. |
278 | * |
279 | * Use: Does a @select@ call (or equivalent @poll@). |
280 | */ |
281 | |
282 | int sel_select(sel_state *s) |
283 | { |
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284 | sel_args a; |
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285 | int err; |
286 | |
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287 | /* --- Initialize the argument block --- */ |
288 | |
289 | a.maxfd = s->files ? s->files->fd + 1 : 0; |
290 | memcpy(a.fd, s->fd, sizeof(a.fd)); |
291 | if (s->timers || s->hooks) |
292 | gettimeofday(&a.now, 0); |
293 | if (!s->timers) |
294 | a.tvp = 0; |
295 | else { |
296 | TV_SUB(&a.tv, &s->timers->tv, &a.now); |
297 | a.tvp = &a.tv; |
298 | } |
299 | |
300 | /* --- Grind through the pre hooks --- */ |
301 | |
302 | { |
303 | sel_hook *h = s->hooks; |
304 | while (h) { |
305 | sel_hook *hh = h; |
306 | h = h->next; |
307 | if (hh->before) |
308 | hh->before(s, &a, hh->p); |
309 | } |
310 | } |
311 | |
312 | /* --- Run the @select@ call --- */ |
313 | |
314 | if ((err = select(a.maxfd, |
315 | &a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC], |
316 | a.tvp)) < 0) |
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317 | return (err); |
318 | |
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319 | if (a.tvp) |
320 | gettimeofday(&a.now, 0); |
321 | |
322 | /* --- Run through the hooks again --- */ |
323 | |
324 | { |
325 | sel_hook *h = s->hooks; |
326 | while (h) { |
327 | sel_hook *hh = h; |
328 | h = h->next; |
329 | if (hh->after) |
330 | hh->after(s, &a, hh->p); |
331 | } |
332 | } |
333 | |
334 | /* --- Run through the timers --- */ |
335 | |
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336 | { |
337 | sel_timer *t, *tt; |
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338 | for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = tt) { |
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339 | tt = t->next; |
340 | t->next = t->prev = t; |
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341 | t->func(&a.now, t->p); |
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342 | } |
343 | s->timers = t; |
344 | if (t) |
345 | t->prev = (sel_timer *)&s->timers; |
346 | } |
347 | |
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348 | /* --- And finally run through the files --- */ |
349 | |
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350 | { |
351 | sel_file *f, *ff; |
352 | for (f = s->files; f; f = ff) { |
353 | ff = f->next; |
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354 | if (FD_ISSET(f->fd, a.fd + f->mode)) |
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355 | f->func(f->fd, f->mode, f->p); |
356 | } |
357 | } |
358 | |
359 | return (0); |
360 | } |
361 | |
362 | /*----- That's all, folks -------------------------------------------------*/ |