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1cbf4dea | 1 | /* Copyright (C) 1997, 1998, 2000 Free Software Foundation, Inc. |
3666451e MD |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2, or (at your option) | |
6 | * any later version. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this software; see the file COPYING. If not, write to | |
15 | * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, | |
16 | * Boston, MA 02111-1307 USA | |
17 | * | |
18 | * As a special exception, the Free Software Foundation gives permission | |
19 | * for additional uses of the text contained in its release of GUILE. | |
20 | * | |
21 | * The exception is that, if you link the GUILE library with other files | |
22 | * to produce an executable, this does not by itself cause the | |
23 | * resulting executable to be covered by the GNU General Public License. | |
24 | * Your use of that executable is in no way restricted on account of | |
25 | * linking the GUILE library code into it. | |
26 | * | |
27 | * This exception does not however invalidate any other reasons why | |
28 | * the executable file might be covered by the GNU General Public License. | |
29 | * | |
30 | * This exception applies only to the code released by the | |
31 | * Free Software Foundation under the name GUILE. If you copy | |
32 | * code from other Free Software Foundation releases into a copy of | |
33 | * GUILE, as the General Public License permits, the exception does | |
34 | * not apply to the code that you add in this way. To avoid misleading | |
35 | * anyone as to the status of such modified files, you must delete | |
36 | * this exception notice from them. | |
37 | * | |
38 | * If you write modifications of your own for GUILE, it is your choice | |
39 | * whether to permit this exception to apply to your modifications. | |
40 | * If you do not wish that, delete this exception notice. */ | |
41 | \f | |
42 | #include <stdio.h> | |
43 | #include <limits.h> | |
44 | #include <string.h> | |
45 | ||
46 | #include "_scm.h" | |
47 | ||
48 | #include "iselect.h" | |
1cbf4dea MD |
49 | |
50 | #ifdef GUILE_ISELECT | |
51 | ||
3666451e MD |
52 | #include "coop-threads.h" |
53 | ||
4d3bacdd | 54 | #ifdef MISSING_BZERO_DECL |
b8ff5fe9 MD |
55 | extern void bzero (void *, size_t); |
56 | #endif | |
57 | ||
3666451e MD |
58 | \f |
59 | ||
a48b6916 | 60 | /* COOP queue macros */ |
3666451e MD |
61 | #define QEMPTYP(q) (q.t.next == &q.t) |
62 | #define QFIRST(q) (q.t.next) | |
63 | ||
a48b6916 | 64 | /* These macros count the number of bits in a word. */ |
3666451e | 65 | #define SCM_BITS_PER_LONG (8 * sizeof (unsigned long)) |
95f44da9 MD |
66 | /* Use LONG_MAX instead of ULONG_MAX here since not all systems define |
67 | ULONG_MAX */ | |
68 | #if LONG_MAX >> 16 == 0 | |
3666451e MD |
69 | #define SCM_NLONGBITS(p) (bc[((unsigned char *)(p))[0]]\ |
70 | + bc[((unsigned char *)(p))[1]]) | |
95f44da9 | 71 | #elif LONG_MAX >> 32 == 0 |
3666451e MD |
72 | #define SCM_NLONGBITS(p) (bc[((unsigned char *)(p))[0]]\ |
73 | + bc[((unsigned char *)(p))[1]]\ | |
74 | + bc[((unsigned char *)(p))[2]]\ | |
75 | + bc[((unsigned char *)(p))[3]]) | |
95f44da9 | 76 | #elif LONG_MAX >> 64 == 0 |
3666451e MD |
77 | #define SCM_NLONGBITS(p) (bc[((unsigned char *)(p))[0]]\ |
78 | + bc[((unsigned char *)(p))[1]]\ | |
79 | + bc[((unsigned char *)(p))[2]]\ | |
80 | + bc[((unsigned char *)(p))[3]]\ | |
81 | + bc[((unsigned char *)(p))[4]]\ | |
82 | + bc[((unsigned char *)(p))[5]]\ | |
83 | + bc[((unsigned char *)(p))[6]]\ | |
84 | + bc[((unsigned char *)(p))[7]]) | |
85 | #endif | |
86 | ||
87 | #ifdef HAVE_BZERO | |
88 | #define FD_ZERO_N(pos, n) bzero ((pos), (n)) | |
89 | #else | |
90 | #define FD_ZERO_N(pos, n) memset ((void *) (pos), 0, (n)) | |
91 | #endif | |
92 | ||
93 | typedef unsigned long *ulongptr; | |
94 | ||
95 | static char bc[256]; /* Bit counting array. bc[x] is the number of | |
96 | bits in x. */ | |
97 | ||
c69dfa65 MD |
98 | int scm_I_am_dead; |
99 | ||
a48b6916 MD |
100 | /* This flag indicates that several threads are waiting on the same |
101 | file descriptor. When this is the case, the common fd sets are | |
102 | updated in a more inefficient way. */ | |
103 | int collisionp; | |
104 | ||
105 | /* These are the common fd sets. When new select calls are made, | |
106 | those sets are merged into these. */ | |
3666451e MD |
107 | int gnfds; |
108 | SELECT_TYPE greadfds; | |
109 | SELECT_TYPE gwritefds; | |
110 | SELECT_TYPE gexceptfds; | |
a48b6916 MD |
111 | |
112 | /* These are the result sets. They are used when we call OS select. | |
113 | We couldn't use the common fd sets above, since that would destroy | |
114 | them. */ | |
3666451e MD |
115 | SELECT_TYPE rreadfds; |
116 | SELECT_TYPE rwritefds; | |
117 | SELECT_TYPE rexceptfds; | |
a48b6916 MD |
118 | |
119 | /* Constant timeval struct representing a zero timeout which we use | |
120 | when polling. */ | |
3666451e MD |
121 | static struct timeval timeout0; |
122 | ||
3666451e | 123 | /* As select, but doesn't destroy the file descriptor sets passed as |
a48b6916 | 124 | arguments. The results are stored into the result sets. */ |
3666451e MD |
125 | static int |
126 | safe_select (int nfds, | |
127 | SELECT_TYPE *readfds, | |
128 | SELECT_TYPE *writefds, | |
129 | SELECT_TYPE *exceptfds, | |
130 | struct timeval *timeout) | |
131 | { | |
132 | int n = (nfds + 7) / 8; | |
133 | /* Copy file descriptor sets to result area */ | |
134 | if (readfds == NULL) | |
135 | FD_ZERO (&rreadfds); | |
136 | else | |
137 | { | |
138 | memcpy (&rreadfds, readfds, n); | |
139 | FD_ZERO_N ((char *) &rreadfds + n, SELECT_SET_SIZE / 8 - n); | |
140 | } | |
141 | if (writefds == NULL) | |
142 | FD_ZERO (&rwritefds); | |
143 | else | |
144 | { | |
145 | memcpy (&rwritefds, writefds, n); | |
146 | FD_ZERO_N ((char *) &rwritefds + n, SELECT_SET_SIZE / 8 - n); | |
147 | } | |
148 | if (exceptfds == NULL) | |
149 | FD_ZERO (&rexceptfds); | |
150 | else | |
151 | { | |
152 | memcpy (&rexceptfds, exceptfds, n); | |
153 | FD_ZERO_N ((char *) &rexceptfds + n, SELECT_SET_SIZE / 8 - n); | |
154 | } | |
155 | return select (nfds, &rreadfds, &rwritefds, &rexceptfds, timeout); | |
156 | } | |
157 | ||
a48b6916 MD |
158 | /* Merge new file descriptor sets into the common sets. */ |
159 | static void | |
160 | add_fd_sets (coop_t *t) | |
3666451e | 161 | { |
a48b6916 MD |
162 | int n = (t->nfds + SCM_BITS_PER_LONG - 1) / SCM_BITS_PER_LONG; |
163 | int i; | |
164 | ||
165 | /* Detect if the fd sets of the thread have any bits in common with | |
166 | the rest of the waiting threads. If that is so, set the | |
167 | collision flag. This causes a more time consuming handling of | |
168 | the common fd sets---they need to recalculated every time a | |
169 | thread wakes up. */ | |
170 | if (!collisionp) | |
171 | for (i = 0; i < n; ++i) | |
172 | if ((t->readfds != NULL | |
173 | && (((ulongptr) t->readfds)[i] & ((ulongptr) &greadfds)[i]) != 0) | |
174 | || (t->writefds != NULL | |
175 | && ((((ulongptr) t->writefds)[i] & ((ulongptr) &gwritefds)[i]) | |
176 | != 0)) | |
177 | || (t->exceptfds != NULL | |
178 | && ((((ulongptr) t->exceptfds)[i] & ((ulongptr) &gexceptfds)[i]) | |
179 | != 0))) | |
180 | { | |
181 | collisionp = 1; | |
182 | break; | |
183 | } | |
184 | ||
185 | /* We recalculate nfds below. The cost for this can be paid back | |
186 | with a great bonus since many programs are lazy with the nfds | |
187 | arg. Many even pass 1024 when using one of the lowest fd:s! | |
188 | ||
189 | We approach from above, checking for non-zero bits. As soon as | |
190 | we have determined the value of nfds, we jump down to code below | |
191 | which concludes the updating of the common sets. */ | |
192 | t->nfds = 0; | |
193 | i = n; | |
3666451e MD |
194 | while (i > 0) |
195 | { | |
196 | --i; | |
a48b6916 | 197 | if (t->readfds != NULL && ((ulongptr) t->readfds)[i] != 0) |
3666451e | 198 | { |
a48b6916 | 199 | ((ulongptr) &greadfds)[i] |= ((ulongptr) t->readfds)[i]; |
3666451e | 200 | n = (i + 1) * SCM_BITS_PER_LONG; |
a48b6916 | 201 | t->nfds = n; |
3666451e MD |
202 | if (n > gnfds) |
203 | gnfds = n; | |
204 | goto cont_read; | |
205 | } | |
a48b6916 | 206 | if (t->writefds != NULL && ((ulongptr) t->writefds)[i] != 0) |
3666451e | 207 | { |
a48b6916 | 208 | ((ulongptr) &gwritefds)[i] |= ((ulongptr) t->writefds)[i]; |
3666451e | 209 | n = (i + 1) * SCM_BITS_PER_LONG; |
a48b6916 | 210 | t->nfds = n; |
3666451e MD |
211 | if (n > gnfds) |
212 | gnfds = n; | |
213 | goto cont_write; | |
214 | } | |
a48b6916 | 215 | if (t->exceptfds != NULL && ((ulongptr) t->exceptfds)[i] != 0) |
3666451e | 216 | { |
a48b6916 | 217 | ((ulongptr) &gexceptfds)[i] |= ((ulongptr) t->exceptfds)[i]; |
3666451e | 218 | n = (i + 1) * SCM_BITS_PER_LONG; |
a48b6916 | 219 | t->nfds = n; |
3666451e MD |
220 | if (n > gnfds) |
221 | gnfds = n; | |
222 | goto cont_except; | |
223 | } | |
224 | } | |
a48b6916 MD |
225 | return; |
226 | ||
227 | /* nfds is now determined. Just finish updating the common sets. */ | |
3666451e MD |
228 | while (i > 0) |
229 | { | |
230 | --i; | |
a48b6916 MD |
231 | if (t->readfds != NULL && ((ulongptr) t->readfds)[i] != 0) |
232 | ((ulongptr) &greadfds)[i] |= ((ulongptr) t->readfds)[i]; | |
3666451e | 233 | cont_read: |
a48b6916 MD |
234 | if (t->writefds != NULL && ((ulongptr) t->writefds)[i] != 0) |
235 | ((ulongptr) &gwritefds)[i] |= ((ulongptr) t->writefds)[i]; | |
3666451e | 236 | cont_write: |
a48b6916 MD |
237 | if (t->exceptfds != NULL && ((ulongptr) t->exceptfds)[i] != 0) |
238 | ((ulongptr) &gexceptfds)[i] |= ((ulongptr) t->exceptfds)[i]; | |
3666451e MD |
239 | cont_except: |
240 | } | |
3666451e MD |
241 | } |
242 | ||
a48b6916 MD |
243 | /* Update the fd sets pointed to by the thread so that they reflect |
244 | the status of the file descriptors which the thread was interested | |
245 | in. Also clear those bits in the common sets. This function is | |
246 | only called when there are no bit collisions. */ | |
3666451e MD |
247 | static void |
248 | finalize_fd_sets (coop_t *t) | |
249 | { | |
250 | int i = (t->nfds + SCM_BITS_PER_LONG - 1) / SCM_BITS_PER_LONG; | |
251 | int n_ones = 0; | |
252 | register unsigned long s; | |
a48b6916 | 253 | |
3666451e MD |
254 | if (t->nfds == gnfds) |
255 | { | |
a48b6916 MD |
256 | /* This thread is the one responsible for the current high value |
257 | of gnfds. First do our other jobs while at the same time | |
258 | trying to decrease gnfds. */ | |
3666451e MD |
259 | while (i > 0) |
260 | { | |
261 | --i; | |
262 | if (t->readfds != NULL && (s = ((ulongptr) t->readfds)[i]) != 0) | |
263 | { | |
264 | ((ulongptr) t->readfds)[i] &= ((ulongptr) &rreadfds)[i]; | |
265 | ((ulongptr) &greadfds)[i] &= ~s; | |
266 | n_ones += SCM_NLONGBITS (&((ulongptr) t->readfds)[i]); | |
267 | } | |
268 | if (((ulongptr) &greadfds)[i] != 0) | |
269 | { | |
270 | gnfds = (i + 1) * SCM_BITS_PER_LONG; | |
271 | goto cont_read; | |
272 | } | |
273 | if (t->writefds != NULL && (s = ((ulongptr) t->writefds)[i]) != 0) | |
274 | { | |
275 | ((ulongptr) t->writefds)[i] &= ((ulongptr) &rwritefds)[i]; | |
276 | ((ulongptr) &gwritefds)[i] &= ~s; | |
277 | n_ones += SCM_NLONGBITS (&((ulongptr) t->writefds)[i]); | |
278 | } | |
279 | if (((ulongptr) &gwritefds)[i] != 0) | |
280 | { | |
281 | gnfds = (i + 1) * SCM_BITS_PER_LONG; | |
282 | goto cont_write; | |
283 | } | |
284 | if (t->exceptfds != NULL && (s = ((ulongptr) t->exceptfds)[i]) != 0) | |
285 | { | |
286 | ((ulongptr) t->exceptfds)[i] &= ((ulongptr) &rexceptfds)[i]; | |
287 | ((ulongptr) &gexceptfds)[i] &= ~s; | |
288 | n_ones += SCM_NLONGBITS (&((ulongptr) t->exceptfds)[i]); | |
289 | } | |
290 | if (((ulongptr) &gexceptfds)[i] != 0) | |
291 | { | |
292 | gnfds = (i + 1) * SCM_BITS_PER_LONG; | |
293 | goto cont_except; | |
294 | } | |
295 | } | |
296 | gnfds = 0; | |
297 | t->retval = n_ones; | |
298 | return; | |
299 | } | |
a48b6916 MD |
300 | |
301 | /* Either this thread wasn't responsible for gnfds or gnfds has been | |
302 | determined. */ | |
3666451e MD |
303 | while (i > 0) |
304 | { | |
305 | --i; | |
306 | if (t->readfds != NULL && (s = ((ulongptr) t->readfds)[i]) != 0) | |
307 | { | |
308 | ((ulongptr) t->readfds)[i] &= ((ulongptr) &rreadfds)[i]; | |
309 | ((ulongptr) &greadfds)[i] &= ~s; | |
310 | n_ones += SCM_NLONGBITS (&((ulongptr) t->readfds)[i]); | |
311 | } | |
312 | cont_read: | |
313 | if (t->writefds != NULL && (s = ((ulongptr) t->writefds)[i]) != 0) | |
314 | { | |
315 | ((ulongptr) t->writefds)[i] &= ((ulongptr) &rwritefds)[i]; | |
316 | ((ulongptr) &gwritefds)[i] &= ~s; | |
cafc12ff | 317 | n_ones += SCM_NLONGBITS (&((ulongptr) t->writefds)[i]); |
3666451e MD |
318 | } |
319 | cont_write: | |
320 | if (t->exceptfds != NULL && (s = ((ulongptr) t->exceptfds)[i]) != 0) | |
321 | { | |
322 | ((ulongptr) t->exceptfds)[i] &= ((ulongptr) &rexceptfds)[i]; | |
323 | ((ulongptr) &gexceptfds)[i] &= ~s; | |
cafc12ff | 324 | n_ones += SCM_NLONGBITS (&((ulongptr) t->exceptfds)[i]); |
3666451e MD |
325 | } |
326 | cont_except: | |
95f44da9 | 327 | ; |
3666451e MD |
328 | } |
329 | t->retval = n_ones; | |
330 | } | |
331 | ||
a48b6916 MD |
332 | /* Just like finalize_fd_sets except that we don't have to update the |
333 | global fd sets. Those will be recalulated elsewhere. */ | |
334 | static void | |
335 | finalize_fd_sets_lazily (coop_t *t) | |
336 | { | |
337 | int i = (t->nfds + SCM_BITS_PER_LONG - 1) / SCM_BITS_PER_LONG; | |
338 | int n_ones = 0; | |
a48b6916 MD |
339 | while (i > 0) |
340 | { | |
341 | --i; | |
3237b129 | 342 | if (t->readfds != NULL && ((ulongptr) t->readfds)[i] != 0) |
a48b6916 MD |
343 | { |
344 | ((ulongptr) t->readfds)[i] &= ((ulongptr) &rreadfds)[i]; | |
345 | n_ones += SCM_NLONGBITS (&((ulongptr) t->readfds)[i]); | |
346 | } | |
3237b129 | 347 | if (t->writefds != NULL && ((ulongptr) t->writefds)[i] != 0) |
a48b6916 MD |
348 | { |
349 | ((ulongptr) t->writefds)[i] &= ((ulongptr) &rwritefds)[i]; | |
350 | n_ones += SCM_NLONGBITS (&((ulongptr) t->writefds)[i]); | |
351 | } | |
3237b129 | 352 | if (t->exceptfds != NULL && ((ulongptr) t->exceptfds)[i] != 0) |
a48b6916 MD |
353 | { |
354 | ((ulongptr) t->exceptfds)[i] &= ((ulongptr) &rexceptfds)[i]; | |
355 | n_ones += SCM_NLONGBITS (&((ulongptr) t->exceptfds)[i]); | |
356 | } | |
357 | } | |
358 | t->retval = n_ones; | |
359 | } | |
360 | ||
361 | /* Return first fd with a non-zero bit in any of the result sets. */ | |
3666451e MD |
362 | static int |
363 | first_interesting_fd (void) | |
364 | { | |
365 | int i = 0; | |
366 | SELECT_TYPE *s; | |
367 | while (1) | |
368 | { | |
369 | if (((ulongptr) &rreadfds)[i] != 0) | |
370 | { | |
371 | s = &rreadfds; | |
372 | break; | |
373 | } | |
374 | if (((ulongptr) &rwritefds)[i] != 0) | |
375 | { | |
376 | s = &rwritefds; | |
377 | break; | |
378 | } | |
379 | if (((ulongptr) &rexceptfds)[i] != 0) | |
380 | { | |
381 | s = &rexceptfds; | |
382 | break; | |
383 | } | |
384 | ++i; | |
385 | } | |
386 | i *= SCM_BITS_PER_LONG; | |
387 | while (i < gnfds) | |
388 | { | |
389 | if (FD_ISSET (i, s)) | |
390 | return i; | |
391 | ++i; | |
392 | } | |
393 | fprintf (stderr, "first_interesting_fd: internal error\n"); | |
394 | exit (1); | |
395 | } | |
396 | ||
a48b6916 | 397 | /* Revive all threads with an error status. */ |
c69dfa65 MD |
398 | void |
399 | scm_error_revive_threads (void) | |
3666451e MD |
400 | { |
401 | coop_t *t; | |
402 | ||
403 | while ((t = coop_qget (&coop_global_sleepq)) != NULL) | |
404 | { | |
c44bfbc9 | 405 | t->_errno = errno; |
3666451e | 406 | t->retval = -1; |
c69dfa65 MD |
407 | if (t != coop_global_curr) |
408 | coop_qput (&coop_global_runq, t); | |
3666451e | 409 | } |
c69dfa65 | 410 | collisionp = 0; |
3666451e MD |
411 | gnfds = 0; |
412 | FD_ZERO (&greadfds); | |
413 | FD_ZERO (&gwritefds); | |
414 | FD_ZERO (&gexceptfds); | |
415 | } | |
416 | ||
a48b6916 MD |
417 | /* Given the result of a call to safe_select and the current time, |
418 | try to wake up some threads and return the first one. Return NULL | |
419 | if we couldn't find any. */ | |
3666451e | 420 | static coop_t * |
c69dfa65 | 421 | find_thread (int n, struct timeval *now, int sleepingp) |
3666451e MD |
422 | { |
423 | coop_t *t; | |
424 | int fd; | |
425 | ||
c69dfa65 MD |
426 | if (n < 0) |
427 | /* An error or a signal has occured. Wake all threads. Since we | |
428 | don't care to calculate if there is a sinner we report the | |
429 | error to all of them. */ | |
430 | { | |
431 | scm_error_revive_threads (); | |
432 | if (!scm_I_am_dead) | |
433 | return coop_global_curr; | |
434 | } | |
435 | else if (n == 0) | |
3666451e MD |
436 | { |
437 | while (!QEMPTYP (coop_global_sleepq) | |
438 | && (t = QFIRST (coop_global_sleepq))->timeoutp | |
439 | && (t->wakeup_time.tv_sec < now->tv_sec | |
440 | || (t->wakeup_time.tv_sec == now->tv_sec | |
441 | && t->wakeup_time.tv_usec <= now->tv_usec))) | |
442 | { | |
443 | coop_qget (&coop_global_sleepq); | |
a48b6916 MD |
444 | if (collisionp) |
445 | finalize_fd_sets_lazily (t); | |
446 | else | |
447 | finalize_fd_sets (t); | |
3666451e MD |
448 | coop_qput (&coop_global_runq, t); |
449 | } | |
a48b6916 MD |
450 | if (collisionp) |
451 | { | |
452 | while ((t = coop_qget (&coop_global_sleepq)) != NULL) | |
453 | coop_qput (&coop_tmp_queue, t); | |
454 | goto rebuild_global_fd_sets; | |
455 | } | |
3666451e MD |
456 | } |
457 | else if (n > 0) | |
458 | { | |
459 | /* Find the first interesting file descriptor */ | |
460 | fd = first_interesting_fd (); | |
461 | /* Check the sleeping queue for this file descriptor. | |
462 | Other file descriptors will be handled next time | |
463 | coop_next_runnable_thread is called. */ | |
464 | /* This code is inefficient. We'll improve it later. */ | |
465 | while ((t = coop_qget (&coop_global_sleepq)) != NULL) | |
466 | { | |
467 | if ((t->readfds && FD_ISSET (fd, t->readfds)) | |
468 | || (t->writefds && FD_ISSET (fd, t->writefds)) | |
469 | || (t->exceptfds && FD_ISSET (fd, t->exceptfds)) | |
470 | || (t->timeoutp | |
471 | && (t->wakeup_time.tv_sec < now->tv_sec | |
472 | || (t->wakeup_time.tv_sec == now->tv_sec | |
473 | && t->wakeup_time.tv_usec <= now->tv_usec)))) | |
474 | { | |
a48b6916 MD |
475 | if (collisionp) |
476 | finalize_fd_sets_lazily (t); | |
477 | else | |
478 | finalize_fd_sets (t); | |
3666451e MD |
479 | coop_qput (&coop_global_runq, t); |
480 | } | |
481 | else | |
482 | coop_qput(&coop_tmp_queue, t); | |
483 | } | |
a48b6916 MD |
484 | if (collisionp) |
485 | { | |
486 | rebuild_global_fd_sets: | |
487 | collisionp = 0; | |
488 | gnfds = 0; | |
489 | FD_ZERO (&greadfds); | |
490 | FD_ZERO (&gwritefds); | |
491 | FD_ZERO (&gexceptfds); | |
492 | while ((t = coop_qget (&coop_tmp_queue)) != NULL) | |
493 | { | |
494 | add_fd_sets (t); | |
495 | coop_qput (&coop_global_sleepq, t); | |
496 | } | |
497 | } | |
498 | else | |
499 | { | |
500 | while ((t = coop_qget (&coop_tmp_queue)) != NULL) | |
501 | coop_qput (&coop_global_sleepq, t); | |
502 | } | |
3666451e | 503 | } |
3666451e MD |
504 | |
505 | return coop_qget (&coop_global_runq); | |
506 | } | |
507 | ||
508 | /* Return next runnable thread on the run queue. | |
509 | * First update the queue with possible I/O or timeouts. | |
510 | * If no thread is found, return NULL. | |
511 | */ | |
512 | coop_t * | |
513 | coop_next_runnable_thread () | |
514 | { | |
81e81a5c | 515 | coop_t *t; |
3666451e MD |
516 | struct timeval now; |
517 | int n; | |
518 | ||
519 | /* Just return next thread on the runq if the sleepq is empty. */ | |
520 | if (QEMPTYP (coop_global_sleepq)) | |
c69dfa65 MD |
521 | { |
522 | if (QEMPTYP (coop_global_runq)) | |
523 | return coop_global_curr; | |
524 | else | |
525 | return coop_qget (&coop_global_runq); | |
526 | } | |
3666451e MD |
527 | |
528 | if (gnfds > 0) | |
529 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, &timeout0); | |
530 | else | |
531 | n = 0; | |
532 | if (QFIRST (coop_global_sleepq)->timeoutp) | |
533 | { | |
534 | gettimeofday (&now, NULL); | |
c69dfa65 | 535 | t = find_thread (n, &now, 0); |
3666451e | 536 | } |
81e81a5c | 537 | else |
c69dfa65 MD |
538 | t = find_thread (n, 0, 0); |
539 | return t == NULL ? coop_global_curr : t; | |
3666451e MD |
540 | } |
541 | ||
542 | coop_t * | |
543 | coop_wait_for_runnable_thread_now (struct timeval *now) | |
544 | { | |
545 | int n; | |
546 | coop_t *t; | |
547 | ||
548 | if (gnfds > 0) | |
549 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, &timeout0); | |
550 | else | |
551 | n = 0; | |
552 | /* Is there any other runnable thread? */ | |
c69dfa65 | 553 | t = find_thread (n, now, 1); |
3666451e MD |
554 | while (t == NULL) |
555 | { | |
556 | /* No. Let the process go to sleep. */ | |
557 | if ((t = QFIRST (coop_global_sleepq))->timeoutp) | |
558 | { | |
559 | now->tv_sec = t->wakeup_time.tv_sec - now->tv_sec; | |
560 | if (now->tv_usec > t->wakeup_time.tv_usec) | |
561 | { | |
562 | --now->tv_sec; | |
563 | now->tv_usec = 1000000 + t->wakeup_time.tv_usec - now->tv_usec; | |
564 | } | |
565 | else | |
566 | now->tv_usec = t->wakeup_time.tv_usec - now->tv_usec; | |
567 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, now); | |
568 | } | |
569 | else | |
570 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, NULL); | |
571 | gettimeofday (now, NULL); | |
c69dfa65 | 572 | t = find_thread (n, now, 1); |
3666451e MD |
573 | } |
574 | ||
575 | return t; | |
576 | } | |
577 | ||
578 | coop_t * | |
579 | coop_wait_for_runnable_thread () | |
580 | { | |
581 | struct timeval now; | |
582 | ||
583 | if (QEMPTYP (coop_global_sleepq)) | |
c69dfa65 MD |
584 | { |
585 | if (QEMPTYP (coop_global_runq)) | |
586 | return coop_global_curr; | |
587 | else | |
588 | return coop_qget (&coop_global_runq); | |
589 | } | |
3666451e MD |
590 | |
591 | if (QFIRST (coop_global_sleepq)->timeoutp) | |
592 | gettimeofday (&now, NULL); | |
593 | ||
594 | return coop_wait_for_runnable_thread_now (&now); | |
595 | } | |
596 | ||
1cbf4dea MD |
597 | /* Initialize bit counting array */ |
598 | static void init_bc (int bit, int i, int n) | |
599 | { | |
600 | if (bit == 0) | |
601 | bc[i] = n; | |
602 | else | |
603 | { | |
604 | init_bc (bit >> 1, i, n); | |
605 | init_bc (bit >> 1, i | bit, n + 1); | |
606 | } | |
607 | } | |
608 | ||
609 | void | |
610 | scm_init_iselect () | |
611 | { | |
612 | #if 0 /* This is just symbolic */ | |
613 | collisionp = 0; | |
614 | gnfds = 0; | |
615 | FD_ZERO (&greadfds); | |
616 | FD_ZERO (&gwritefds); | |
617 | FD_ZERO (&gexceptfds); | |
618 | timeout0.tv_sec = 0; | |
619 | timeout0.tv_usec = 0; | |
620 | #endif | |
621 | init_bc (0x80, 0, 0); | |
622 | #include "iselect.x" | |
623 | } | |
624 | ||
625 | #endif /* GUILE_ISELECT */ | |
626 | ||
3666451e MD |
627 | int |
628 | scm_internal_select (int nfds, | |
629 | SELECT_TYPE *readfds, | |
630 | SELECT_TYPE *writefds, | |
631 | SELECT_TYPE *exceptfds, | |
632 | struct timeval *timeout) | |
633 | { | |
1cbf4dea MD |
634 | #ifndef GUILE_ISELECT |
635 | int res = select (nfds, readfds, writefds, exceptfds, timeout); | |
636 | SCM_ASYNC_TICK; | |
637 | return res; | |
638 | #else /* GUILE_ISELECT */ | |
3666451e MD |
639 | struct timeval now; |
640 | coop_t *t, *curr = coop_global_curr; | |
c69dfa65 | 641 | |
3666451e MD |
642 | /* If the timeout is 0, we're polling and can handle it quickly. */ |
643 | if (timeout != NULL | |
644 | && timeout->tv_sec == 0 | |
645 | && timeout->tv_usec == 0) | |
646 | return select (nfds, readfds, writefds, exceptfds, timeout); | |
647 | ||
c69dfa65 | 648 | SCM_DEFER_INTS; |
c718cb07 | 649 | |
3666451e | 650 | /* Add our file descriptor flags to the common set. */ |
3237b129 MD |
651 | curr->nfds = nfds; |
652 | curr->readfds = readfds; | |
653 | curr->writefds = writefds; | |
654 | curr->exceptfds = exceptfds; | |
655 | add_fd_sets (curr); | |
3666451e MD |
656 | |
657 | /* Place ourselves on the sleep queue and get a new thread to run. */ | |
658 | if (timeout == NULL) | |
659 | { | |
660 | curr->timeoutp = 0; | |
661 | coop_qput (&coop_global_sleepq, curr); | |
662 | t = coop_wait_for_runnable_thread (); | |
663 | } | |
664 | else | |
665 | { | |
666 | gettimeofday (&now, NULL); | |
667 | curr->timeoutp = 1; | |
668 | curr->wakeup_time.tv_sec = now.tv_sec + timeout->tv_sec; | |
669 | curr->wakeup_time.tv_usec = now.tv_usec + timeout->tv_usec; | |
670 | if (curr->wakeup_time.tv_usec >= 1000000) | |
671 | { | |
672 | ++curr->wakeup_time.tv_sec; | |
673 | curr->wakeup_time.tv_usec -= 1000000; | |
674 | } | |
675 | /* Insert the current thread at the right place in the sleep queue */ | |
676 | coop_timeout_qinsert (&coop_global_sleepq, curr); | |
677 | t = coop_wait_for_runnable_thread_now (&now); | |
678 | } | |
679 | ||
680 | /* If the new thread is the same as the sleeping thread, do nothing */ | |
c69dfa65 | 681 | if (t != coop_global_curr) |
3666451e MD |
682 | { |
683 | /* Do a context switch. */ | |
684 | coop_global_curr = t; | |
685 | QT_BLOCK (coop_sleephelp, curr, NULL, t->sp); | |
686 | } | |
687 | ||
c69dfa65 MD |
688 | if (coop_global_curr->retval == -1) |
689 | errno = coop_global_curr->_errno; | |
690 | SCM_ALLOW_INTS; | |
1cbf4dea | 691 | SCM_ASYNC_TICK; |
c69dfa65 | 692 | return coop_global_curr->retval; |
1cbf4dea | 693 | #endif /* GUILE_ISELECT */ |
3666451e | 694 | } |