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97f65b00 | 1 | /* -*-c-*- |
2 | * | |
97f65b00 | 3 | * I/O multiplexing support |
4 | * | |
a3ddb778 | 5 | * (c) 1999 Straylight/Edgeware |
97f65b00 | 6 | */ |
7 | ||
d4efbcd9 | 8 | /*----- Licensing notice --------------------------------------------------* |
97f65b00 | 9 | * |
10 | * This file is part of the mLib utilities library. | |
11 | * | |
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. | |
d4efbcd9 | 16 | * |
97f65b00 | 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. | |
d4efbcd9 | 21 | * |
97f65b00 | 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, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
97f65b00 | 28 | /*----- Header files ------------------------------------------------------*/ |
29 | ||
0a2a19b4 | 30 | #include <assert.h> |
97f65b00 | 31 | #include <stdio.h> |
32 | #include <stdlib.h> | |
33 | #include <string.h> | |
34 | ||
35 | #include <sys/types.h> | |
36 | #include <sys/time.h> | |
37 | #include <unistd.h> | |
38 | ||
39 | #include "sel.h" | |
0a2a19b4 | 40 | #include "sub.h" |
97f65b00 | 41 | #include "tv.h" |
42 | ||
0a2a19b4 | 43 | /*----- Data structures ---------------------------------------------------*/ |
44 | ||
45 | typedef struct sel_pendfile { | |
46 | struct sel_pendfile *next; | |
47 | sel_file *f; | |
48 | } pfile; | |
49 | ||
50 | typedef struct sel_pendtimer { | |
51 | struct sel_pendtimer *next; | |
52 | sel_timer *t; | |
53 | } ptimer; | |
54 | ||
97f65b00 | 55 | /*----- Main code ---------------------------------------------------------*/ |
56 | ||
57 | /* --- @sel_init@ --- * | |
58 | * | |
59 | * Arguments: @sel_state *s@ = pointer to a state block to initialize | |
60 | * | |
61 | * Returns: --- | |
62 | * | |
63 | * Use: Initializes a select state block. | |
64 | */ | |
65 | ||
66 | void sel_init(sel_state *s) | |
67 | { | |
1101f87a | 68 | int i; |
69 | ||
70 | for (i = 0; i < SEL_MODES; i++) { | |
71 | s->files[i] = 0; | |
72 | FD_ZERO(&s->fd[i]); | |
73 | } | |
97f65b00 | 74 | s->timers = 0; |
1226c514 | 75 | s->hooks = 0; |
1101f87a | 76 | s->args = 0; |
97f65b00 | 77 | } |
78 | ||
79 | /* --- @sel_initfile@ --- * | |
80 | * | |
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 | |
87 | * | |
88 | * Returns: --- | |
89 | * | |
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 | |
92 | * @sel_addfile@. | |
93 | */ | |
94 | ||
95 | void sel_initfile(sel_state *s, sel_file *f, | |
96 | int fd, unsigned mode, | |
97 | void (*func)(int /*fd*/, unsigned /*mode*/, void */*p*/), | |
98 | void *p) | |
99 | { | |
100 | f->s = s; | |
101 | f->fd = fd; | |
102 | f->mode = mode; | |
103 | f->func = func; | |
104 | f->p = p; | |
0a2a19b4 | 105 | f->pend = 0; |
97f65b00 | 106 | } |
107 | ||
108 | /* --- @sel_addfile@ --- * | |
109 | * | |
110 | * Arguments: @sel_file *f@ = pointer to a file block | |
111 | * | |
112 | * Returns: --- | |
113 | * | |
114 | * Use: Adds a file block into the list of things to listen to. | |
115 | */ | |
116 | ||
117 | void sel_addfile(sel_file *f) | |
118 | { | |
1101f87a | 119 | sel_file **ff = &f->s->files[f->mode]; |
97f65b00 | 120 | |
121 | /* --- This little dance looks like line-noise, but it does the job --- */ | |
122 | ||
123 | while (*ff && (*ff)->fd > f->fd) | |
124 | ff = &(*ff)->next; | |
125 | f->next = *ff; | |
4790f418 | 126 | f->prev = ff; |
97f65b00 | 127 | if (*ff) |
4790f418 | 128 | (*ff)->prev = &f->next; |
97f65b00 | 129 | *ff = f; |
130 | FD_SET(f->fd, f->s->fd + f->mode); | |
131 | } | |
132 | ||
1101f87a | 133 | /* --- @sel_force@ --- * |
134 | * | |
135 | * Arguments: @sel_file *f@ = pointer to file selector | |
136 | * | |
137 | * Returns: --- | |
138 | * | |
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 | |
142 | * ready for it. | |
143 | */ | |
144 | ||
145 | void sel_force(sel_file *f) | |
146 | { | |
147 | if (f->s->args) | |
148 | FD_SET(f->fd, &f->s->args->fd[f->mode]); | |
149 | } | |
150 | ||
97f65b00 | 151 | /* --- @sel_rmfile@ --- * |
152 | * | |
153 | * Arguments: @sel_file *f@ = pointer to a file block | |
154 | * | |
155 | * Returns: --- | |
156 | * | |
157 | * Use: Removes a file block from the list of things to listen to. | |
158 | */ | |
159 | ||
160 | void sel_rmfile(sel_file *f) | |
161 | { | |
4790f418 | 162 | *f->prev = f->next; |
97f65b00 | 163 | if (f->next) |
164 | f->next->prev = f->prev; | |
165 | FD_CLR(f->fd, f->s->fd + f->mode); | |
0a2a19b4 | 166 | if (f->pend) { |
167 | f->pend->f = 0; | |
168 | f->pend = 0; | |
169 | } | |
97f65b00 | 170 | } |
171 | ||
172 | /* --- @sel_addtimer@ --- * | |
173 | * | |
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 | |
179 | * | |
180 | * Returns: --- | |
181 | * | |
182 | * Use: Registers and sets up a timer. | |
183 | */ | |
184 | ||
185 | void sel_addtimer(sel_state *s, sel_timer *t, | |
186 | struct timeval *tv, | |
187 | void (*func)(struct timeval */*tv*/, void */*p*/), | |
188 | void *p) | |
189 | { | |
190 | sel_timer **tt = &s->timers; | |
0a2a19b4 | 191 | { sel_timer *q; for (q = s->timers; q; q = q->next) assert(q != t); } |
97f65b00 | 192 | |
193 | /* --- Set up the timer block --- */ | |
194 | ||
195 | t->tv = *tv; | |
196 | t->func = func; | |
197 | t->p = p; | |
0a2a19b4 | 198 | t->pend = 0; |
97f65b00 | 199 | |
200 | /* --- More line noise --- */ | |
d4efbcd9 | 201 | |
c05c6d83 | 202 | while (*tt && TV_CMP(&(*tt)->tv, <, tv)) |
97f65b00 | 203 | tt = &(*tt)->next; |
204 | t->next = *tt; | |
4790f418 | 205 | t->prev = tt; |
97f65b00 | 206 | if (*tt) |
4790f418 | 207 | (*tt)->prev = &t->next; |
97f65b00 | 208 | *tt = t; |
209 | } | |
210 | ||
211 | /* --- @sel_rmtimer@ --- * | |
212 | * | |
213 | * Arguments: @sel_timer *t@ = pointer to timer block | |
214 | * | |
215 | * Returns: --- | |
216 | * | |
217 | * Use: Removes a timer from the list of timers. | |
218 | */ | |
219 | ||
220 | void sel_rmtimer(sel_timer *t) | |
221 | { | |
0a2a19b4 | 222 | if (t->pend) { |
223 | t->pend->t = 0; | |
224 | t->pend = 0; | |
4790f418 | 225 | } else { |
226 | *t->prev = t->next; | |
227 | if (t->next) | |
228 | t->next->prev = t->prev; | |
0a2a19b4 | 229 | } |
97f65b00 | 230 | } |
231 | ||
1226c514 | 232 | /* --- @sel_addhook@ --- * |
233 | * | |
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 | |
238 | * | |
239 | * Returns: --- | |
240 | * | |
241 | * Use: Registers hook functions to be called on each select call. | |
242 | */ | |
243 | ||
244 | void sel_addhook(sel_state *s, sel_hook *h, | |
245 | sel_hookfn before, sel_hookfn after, | |
246 | void *p) | |
247 | { | |
248 | h->before = before; | |
249 | h->after = after; | |
250 | h->p = p; | |
251 | h->next = s->hooks; | |
4790f418 | 252 | h->prev = &s->hooks; |
1226c514 | 253 | if (s->hooks) |
4790f418 | 254 | s->hooks->prev = &h->next; |
1226c514 | 255 | s->hooks = h; |
256 | } | |
257 | ||
258 | /* --- @sel_rmhook@ --- * | |
259 | * | |
260 | * Arguments: @sel_hook *h@ = pointer to hook block | |
261 | * | |
262 | * Returns: --- | |
263 | * | |
264 | * Use: Removes hook functions. | |
265 | */ | |
266 | ||
267 | void sel_rmhook(sel_hook *h) | |
268 | { | |
269 | if (h->next) | |
270 | h->next->prev = h->prev; | |
4790f418 | 271 | *h->prev = h->next; |
1226c514 | 272 | } |
273 | ||
274 | /* --- @sel_fdmerge@ --- * | |
932341d9 | 275 | * |
d4efbcd9 MW |
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 | |
1226c514 | 279 | * |
d4efbcd9 | 280 | * Returns: Actual highest numbered descriptor. |
1226c514 | 281 | * |
d4efbcd9 MW |
282 | * Use: Merges file descriptor sets, and returns an accurate @maxfd@ |
283 | * value. | |
1226c514 | 284 | */ |
285 | ||
286 | int sel_fdmerge(fd_set *dest, fd_set *fd, int maxfd) | |
287 | { | |
288 | int i, m = -1; | |
289 | ||
290 | for (i = 0; i < maxfd; i++) { | |
291 | if (FD_ISSET(i, fd)) { | |
292 | FD_SET(i, dest); | |
293 | m = i; | |
294 | } | |
295 | } | |
296 | ||
297 | return (m + 1); | |
298 | } | |
299 | ||
97f65b00 | 300 | /* --- @sel_select@ --- * |
301 | * | |
302 | * Arguments: @sel_state *s@ = pointer to state block | |
303 | * | |
304 | * Returns: Zero if all OK, -1 on error. | |
305 | * | |
306 | * Use: Does a @select@ call (or equivalent @poll@). | |
307 | */ | |
308 | ||
309 | int sel_select(sel_state *s) | |
310 | { | |
1226c514 | 311 | sel_args a; |
97f65b00 | 312 | int err; |
313 | ||
1226c514 | 314 | /* --- Initialize the argument block --- */ |
315 | ||
1101f87a | 316 | { |
317 | int i; | |
318 | a.maxfd = 0; | |
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; | |
322 | } | |
323 | } | |
324 | ||
1226c514 | 325 | memcpy(a.fd, s->fd, sizeof(a.fd)); |
326 | if (s->timers || s->hooks) | |
327 | gettimeofday(&a.now, 0); | |
328 | if (!s->timers) | |
329 | a.tvp = 0; | |
330 | else { | |
c1f23e99 | 331 | if (TV_CMP(&s->timers->tv, >, &a.now)) |
332 | TV_SUB(&a.tv, &s->timers->tv, &a.now); | |
333 | else { | |
334 | a.tv.tv_sec = 0; | |
335 | a.tv.tv_usec = 0; | |
336 | } | |
1226c514 | 337 | a.tvp = &a.tv; |
338 | } | |
1101f87a | 339 | s->args = &a; |
1226c514 | 340 | |
341 | /* --- Grind through the pre hooks --- */ | |
342 | ||
343 | { | |
344 | sel_hook *h = s->hooks; | |
345 | while (h) { | |
346 | sel_hook *hh = h; | |
347 | h = h->next; | |
348 | if (hh->before) | |
349 | hh->before(s, &a, hh->p); | |
350 | } | |
351 | } | |
352 | ||
353 | /* --- Run the @select@ call --- */ | |
d4efbcd9 | 354 | |
1226c514 | 355 | if ((err = select(a.maxfd, |
356 | &a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC], | |
1101f87a | 357 | a.tvp)) < 0) { |
358 | s->args = 0; | |
97f65b00 | 359 | return (err); |
1101f87a | 360 | } |
97f65b00 | 361 | |
1226c514 | 362 | if (a.tvp) |
363 | gettimeofday(&a.now, 0); | |
364 | ||
365 | /* --- Run through the hooks again --- */ | |
366 | ||
367 | { | |
368 | sel_hook *h = s->hooks; | |
369 | while (h) { | |
370 | sel_hook *hh = h; | |
371 | h = h->next; | |
372 | if (hh->after) | |
373 | hh->after(s, &a, hh->p); | |
374 | } | |
375 | } | |
376 | ||
377 | /* --- Run through the timers --- */ | |
378 | ||
0a2a19b4 | 379 | if (s->timers) { |
380 | ptimer *pthead, *pt, **ptt = &pthead; | |
381 | sel_timer *t; | |
382 | ||
383 | for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = t->next) { | |
384 | pt = CREATE(ptimer); | |
385 | pt->t = t; | |
386 | t->pend = pt; | |
387 | *ptt = pt; | |
388 | ptt = &pt->next; | |
389 | } | |
390 | *ptt = 0; | |
38472b8e | 391 | if (t) { |
4790f418 | 392 | *t->prev = 0; |
393 | t->prev = &s->timers; | |
38472b8e | 394 | } |
395 | s->timers = t; | |
0a2a19b4 | 396 | while (pthead) { |
397 | pt = pthead; | |
398 | pthead = pt->next; | |
399 | t = pt->t; | |
400 | if (t) { | |
0a2a19b4 | 401 | t->pend = 0; |
4790f418 | 402 | t->next = 0; |
403 | t->prev = &t->next; | |
404 | t->func(&a.now, t->p); | |
0a2a19b4 | 405 | } |
406 | DESTROY(pt); | |
97f65b00 | 407 | } |
97f65b00 | 408 | } |
409 | ||
1101f87a | 410 | /* --- And finally run through the files --- * |
411 | * | |
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. | |
415 | */ | |
1226c514 | 416 | |
97f65b00 | 417 | { |
1101f87a | 418 | int i; |
419 | ||
420 | for (i = 0; i < SEL_MODES; i++) { | |
0a2a19b4 | 421 | pfile *pfhead, *pf, **pff = &pfhead; |
422 | sel_file *f; | |
423 | ||
424 | for (f = s->files[i]; f; f = f->next) { | |
425 | if (!FD_ISSET(f->fd, &a.fd[i])) | |
426 | continue; | |
427 | pf = CREATE(pfile); | |
428 | pf->f = f; | |
429 | f->pend = pf; | |
430 | *pff = pf; | |
431 | pff = &pf->next; | |
432 | } | |
433 | *pff = 0; | |
434 | while (pfhead) { | |
435 | pf = pfhead; | |
436 | pfhead = pf->next; | |
437 | f = pf->f; | |
438 | if (f) { | |
0a2a19b4 | 439 | f->pend = 0; |
4790f418 | 440 | f->func(f->fd, i, f->p); |
0a2a19b4 | 441 | } |
35036742 | 442 | DESTROY(pf); |
1101f87a | 443 | } |
97f65b00 | 444 | } |
445 | } | |
446 | ||
1101f87a | 447 | s->args = 0; |
97f65b00 | 448 | return (0); |
449 | } | |
450 | ||
451 | /*----- That's all, folks -------------------------------------------------*/ |