Commit | Line | Data |
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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 | |
3666451e MD |
42 | #include <limits.h> |
43 | #include <string.h> | |
44 | ||
a26f1191 MV |
45 | #ifdef HAVE_UNISTD_H |
46 | #include <unistd.h> | |
47 | #endif | |
48 | ||
a0599745 MD |
49 | #include "libguile/_scm.h" |
50 | #include "libguile/async.h" | |
3666451e | 51 | |
a0599745 | 52 | #include "libguile/iselect.h" |
1cbf4dea MD |
53 | |
54 | #ifdef GUILE_ISELECT | |
55 | ||
a0599745 | 56 | #include "libguile/coop-threads.h" |
3666451e | 57 | |
4d3bacdd | 58 | #ifdef MISSING_BZERO_DECL |
b8ff5fe9 MD |
59 | extern void bzero (void *, size_t); |
60 | #endif | |
61 | ||
3666451e MD |
62 | \f |
63 | ||
a48b6916 | 64 | /* COOP queue macros */ |
3666451e MD |
65 | #define QEMPTYP(q) (q.t.next == &q.t) |
66 | #define QFIRST(q) (q.t.next) | |
67 | ||
a48b6916 | 68 | /* These macros count the number of bits in a word. */ |
3666451e | 69 | #define SCM_BITS_PER_LONG (8 * sizeof (unsigned long)) |
95f44da9 MD |
70 | /* Use LONG_MAX instead of ULONG_MAX here since not all systems define |
71 | ULONG_MAX */ | |
72 | #if LONG_MAX >> 16 == 0 | |
3666451e MD |
73 | #define SCM_NLONGBITS(p) (bc[((unsigned char *)(p))[0]]\ |
74 | + bc[((unsigned char *)(p))[1]]) | |
c5070877 | 75 | #elif LONG_MAX >> 32 == 0 || LONG_MAX == 2147483647L /* bug in Sun CC 4.2 */ |
3666451e MD |
76 | #define SCM_NLONGBITS(p) (bc[((unsigned char *)(p))[0]]\ |
77 | + bc[((unsigned char *)(p))[1]]\ | |
78 | + bc[((unsigned char *)(p))[2]]\ | |
79 | + bc[((unsigned char *)(p))[3]]) | |
95f44da9 | 80 | #elif LONG_MAX >> 64 == 0 |
3666451e MD |
81 | #define SCM_NLONGBITS(p) (bc[((unsigned char *)(p))[0]]\ |
82 | + bc[((unsigned char *)(p))[1]]\ | |
83 | + bc[((unsigned char *)(p))[2]]\ | |
84 | + bc[((unsigned char *)(p))[3]]\ | |
85 | + bc[((unsigned char *)(p))[4]]\ | |
86 | + bc[((unsigned char *)(p))[5]]\ | |
87 | + bc[((unsigned char *)(p))[6]]\ | |
88 | + bc[((unsigned char *)(p))[7]]) | |
c5070877 MD |
89 | #else |
90 | #error Could not determine suitable definition for SCM_NLONGBITS | |
3666451e MD |
91 | #endif |
92 | ||
93 | #ifdef HAVE_BZERO | |
94 | #define FD_ZERO_N(pos, n) bzero ((pos), (n)) | |
95 | #else | |
96 | #define FD_ZERO_N(pos, n) memset ((void *) (pos), 0, (n)) | |
97 | #endif | |
98 | ||
99 | typedef unsigned long *ulongptr; | |
100 | ||
101 | static char bc[256]; /* Bit counting array. bc[x] is the number of | |
102 | bits in x. */ | |
103 | ||
c69dfa65 MD |
104 | int scm_I_am_dead; |
105 | ||
a48b6916 MD |
106 | /* This flag indicates that several threads are waiting on the same |
107 | file descriptor. When this is the case, the common fd sets are | |
108 | updated in a more inefficient way. */ | |
109 | int collisionp; | |
110 | ||
111 | /* These are the common fd sets. When new select calls are made, | |
112 | those sets are merged into these. */ | |
3666451e MD |
113 | int gnfds; |
114 | SELECT_TYPE greadfds; | |
115 | SELECT_TYPE gwritefds; | |
116 | SELECT_TYPE gexceptfds; | |
a48b6916 MD |
117 | |
118 | /* These are the result sets. They are used when we call OS select. | |
119 | We couldn't use the common fd sets above, since that would destroy | |
120 | them. */ | |
3666451e MD |
121 | SELECT_TYPE rreadfds; |
122 | SELECT_TYPE rwritefds; | |
123 | SELECT_TYPE rexceptfds; | |
a48b6916 MD |
124 | |
125 | /* Constant timeval struct representing a zero timeout which we use | |
126 | when polling. */ | |
3666451e MD |
127 | static struct timeval timeout0; |
128 | ||
3666451e | 129 | /* As select, but doesn't destroy the file descriptor sets passed as |
a48b6916 | 130 | arguments. The results are stored into the result sets. */ |
3666451e MD |
131 | static int |
132 | safe_select (int nfds, | |
133 | SELECT_TYPE *readfds, | |
134 | SELECT_TYPE *writefds, | |
135 | SELECT_TYPE *exceptfds, | |
136 | struct timeval *timeout) | |
137 | { | |
138 | int n = (nfds + 7) / 8; | |
139 | /* Copy file descriptor sets to result area */ | |
140 | if (readfds == NULL) | |
141 | FD_ZERO (&rreadfds); | |
142 | else | |
143 | { | |
144 | memcpy (&rreadfds, readfds, n); | |
145 | FD_ZERO_N ((char *) &rreadfds + n, SELECT_SET_SIZE / 8 - n); | |
146 | } | |
147 | if (writefds == NULL) | |
148 | FD_ZERO (&rwritefds); | |
149 | else | |
150 | { | |
151 | memcpy (&rwritefds, writefds, n); | |
152 | FD_ZERO_N ((char *) &rwritefds + n, SELECT_SET_SIZE / 8 - n); | |
153 | } | |
154 | if (exceptfds == NULL) | |
155 | FD_ZERO (&rexceptfds); | |
156 | else | |
157 | { | |
158 | memcpy (&rexceptfds, exceptfds, n); | |
159 | FD_ZERO_N ((char *) &rexceptfds + n, SELECT_SET_SIZE / 8 - n); | |
160 | } | |
161 | return select (nfds, &rreadfds, &rwritefds, &rexceptfds, timeout); | |
162 | } | |
163 | ||
a48b6916 MD |
164 | /* Merge new file descriptor sets into the common sets. */ |
165 | static void | |
166 | add_fd_sets (coop_t *t) | |
3666451e | 167 | { |
a48b6916 MD |
168 | int n = (t->nfds + SCM_BITS_PER_LONG - 1) / SCM_BITS_PER_LONG; |
169 | int i; | |
170 | ||
171 | /* Detect if the fd sets of the thread have any bits in common with | |
172 | the rest of the waiting threads. If that is so, set the | |
173 | collision flag. This causes a more time consuming handling of | |
174 | the common fd sets---they need to recalculated every time a | |
175 | thread wakes up. */ | |
176 | if (!collisionp) | |
177 | for (i = 0; i < n; ++i) | |
178 | if ((t->readfds != NULL | |
179 | && (((ulongptr) t->readfds)[i] & ((ulongptr) &greadfds)[i]) != 0) | |
180 | || (t->writefds != NULL | |
181 | && ((((ulongptr) t->writefds)[i] & ((ulongptr) &gwritefds)[i]) | |
182 | != 0)) | |
183 | || (t->exceptfds != NULL | |
184 | && ((((ulongptr) t->exceptfds)[i] & ((ulongptr) &gexceptfds)[i]) | |
185 | != 0))) | |
186 | { | |
187 | collisionp = 1; | |
188 | break; | |
189 | } | |
190 | ||
191 | /* We recalculate nfds below. The cost for this can be paid back | |
192 | with a great bonus since many programs are lazy with the nfds | |
193 | arg. Many even pass 1024 when using one of the lowest fd:s! | |
194 | ||
195 | We approach from above, checking for non-zero bits. As soon as | |
196 | we have determined the value of nfds, we jump down to code below | |
197 | which concludes the updating of the common sets. */ | |
198 | t->nfds = 0; | |
199 | i = n; | |
3666451e MD |
200 | while (i > 0) |
201 | { | |
202 | --i; | |
a48b6916 | 203 | if (t->readfds != NULL && ((ulongptr) t->readfds)[i] != 0) |
3666451e | 204 | { |
a48b6916 | 205 | ((ulongptr) &greadfds)[i] |= ((ulongptr) t->readfds)[i]; |
3666451e | 206 | n = (i + 1) * SCM_BITS_PER_LONG; |
a48b6916 | 207 | t->nfds = n; |
3666451e MD |
208 | if (n > gnfds) |
209 | gnfds = n; | |
210 | goto cont_read; | |
211 | } | |
a48b6916 | 212 | if (t->writefds != NULL && ((ulongptr) t->writefds)[i] != 0) |
3666451e | 213 | { |
a48b6916 | 214 | ((ulongptr) &gwritefds)[i] |= ((ulongptr) t->writefds)[i]; |
3666451e | 215 | n = (i + 1) * SCM_BITS_PER_LONG; |
a48b6916 | 216 | t->nfds = n; |
3666451e MD |
217 | if (n > gnfds) |
218 | gnfds = n; | |
219 | goto cont_write; | |
220 | } | |
a48b6916 | 221 | if (t->exceptfds != NULL && ((ulongptr) t->exceptfds)[i] != 0) |
3666451e | 222 | { |
a48b6916 | 223 | ((ulongptr) &gexceptfds)[i] |= ((ulongptr) t->exceptfds)[i]; |
3666451e | 224 | n = (i + 1) * SCM_BITS_PER_LONG; |
a48b6916 | 225 | t->nfds = n; |
3666451e MD |
226 | if (n > gnfds) |
227 | gnfds = n; | |
228 | goto cont_except; | |
229 | } | |
230 | } | |
a48b6916 MD |
231 | return; |
232 | ||
233 | /* nfds is now determined. Just finish updating the common sets. */ | |
3666451e MD |
234 | while (i > 0) |
235 | { | |
236 | --i; | |
a48b6916 MD |
237 | if (t->readfds != NULL && ((ulongptr) t->readfds)[i] != 0) |
238 | ((ulongptr) &greadfds)[i] |= ((ulongptr) t->readfds)[i]; | |
3666451e | 239 | cont_read: |
a48b6916 MD |
240 | if (t->writefds != NULL && ((ulongptr) t->writefds)[i] != 0) |
241 | ((ulongptr) &gwritefds)[i] |= ((ulongptr) t->writefds)[i]; | |
3666451e | 242 | cont_write: |
a48b6916 MD |
243 | if (t->exceptfds != NULL && ((ulongptr) t->exceptfds)[i] != 0) |
244 | ((ulongptr) &gexceptfds)[i] |= ((ulongptr) t->exceptfds)[i]; | |
3666451e | 245 | cont_except: |
26cbcbf9 | 246 | ; |
3666451e | 247 | } |
3666451e MD |
248 | } |
249 | ||
a48b6916 MD |
250 | /* Update the fd sets pointed to by the thread so that they reflect |
251 | the status of the file descriptors which the thread was interested | |
252 | in. Also clear those bits in the common sets. This function is | |
253 | only called when there are no bit collisions. */ | |
3666451e MD |
254 | static void |
255 | finalize_fd_sets (coop_t *t) | |
256 | { | |
257 | int i = (t->nfds + SCM_BITS_PER_LONG - 1) / SCM_BITS_PER_LONG; | |
258 | int n_ones = 0; | |
259 | register unsigned long s; | |
a48b6916 | 260 | |
3666451e MD |
261 | if (t->nfds == gnfds) |
262 | { | |
a48b6916 MD |
263 | /* This thread is the one responsible for the current high value |
264 | of gnfds. First do our other jobs while at the same time | |
265 | trying to decrease gnfds. */ | |
3666451e MD |
266 | while (i > 0) |
267 | { | |
268 | --i; | |
269 | if (t->readfds != NULL && (s = ((ulongptr) t->readfds)[i]) != 0) | |
270 | { | |
271 | ((ulongptr) t->readfds)[i] &= ((ulongptr) &rreadfds)[i]; | |
272 | ((ulongptr) &greadfds)[i] &= ~s; | |
273 | n_ones += SCM_NLONGBITS (&((ulongptr) t->readfds)[i]); | |
274 | } | |
275 | if (((ulongptr) &greadfds)[i] != 0) | |
276 | { | |
277 | gnfds = (i + 1) * SCM_BITS_PER_LONG; | |
278 | goto cont_read; | |
279 | } | |
280 | if (t->writefds != NULL && (s = ((ulongptr) t->writefds)[i]) != 0) | |
281 | { | |
282 | ((ulongptr) t->writefds)[i] &= ((ulongptr) &rwritefds)[i]; | |
283 | ((ulongptr) &gwritefds)[i] &= ~s; | |
284 | n_ones += SCM_NLONGBITS (&((ulongptr) t->writefds)[i]); | |
285 | } | |
286 | if (((ulongptr) &gwritefds)[i] != 0) | |
287 | { | |
288 | gnfds = (i + 1) * SCM_BITS_PER_LONG; | |
289 | goto cont_write; | |
290 | } | |
291 | if (t->exceptfds != NULL && (s = ((ulongptr) t->exceptfds)[i]) != 0) | |
292 | { | |
293 | ((ulongptr) t->exceptfds)[i] &= ((ulongptr) &rexceptfds)[i]; | |
294 | ((ulongptr) &gexceptfds)[i] &= ~s; | |
295 | n_ones += SCM_NLONGBITS (&((ulongptr) t->exceptfds)[i]); | |
296 | } | |
297 | if (((ulongptr) &gexceptfds)[i] != 0) | |
298 | { | |
299 | gnfds = (i + 1) * SCM_BITS_PER_LONG; | |
300 | goto cont_except; | |
301 | } | |
302 | } | |
303 | gnfds = 0; | |
304 | t->retval = n_ones; | |
305 | return; | |
306 | } | |
a48b6916 MD |
307 | |
308 | /* Either this thread wasn't responsible for gnfds or gnfds has been | |
309 | determined. */ | |
3666451e MD |
310 | while (i > 0) |
311 | { | |
312 | --i; | |
313 | if (t->readfds != NULL && (s = ((ulongptr) t->readfds)[i]) != 0) | |
314 | { | |
315 | ((ulongptr) t->readfds)[i] &= ((ulongptr) &rreadfds)[i]; | |
316 | ((ulongptr) &greadfds)[i] &= ~s; | |
317 | n_ones += SCM_NLONGBITS (&((ulongptr) t->readfds)[i]); | |
318 | } | |
319 | cont_read: | |
320 | if (t->writefds != NULL && (s = ((ulongptr) t->writefds)[i]) != 0) | |
321 | { | |
322 | ((ulongptr) t->writefds)[i] &= ((ulongptr) &rwritefds)[i]; | |
323 | ((ulongptr) &gwritefds)[i] &= ~s; | |
cafc12ff | 324 | n_ones += SCM_NLONGBITS (&((ulongptr) t->writefds)[i]); |
3666451e MD |
325 | } |
326 | cont_write: | |
327 | if (t->exceptfds != NULL && (s = ((ulongptr) t->exceptfds)[i]) != 0) | |
328 | { | |
329 | ((ulongptr) t->exceptfds)[i] &= ((ulongptr) &rexceptfds)[i]; | |
330 | ((ulongptr) &gexceptfds)[i] &= ~s; | |
cafc12ff | 331 | n_ones += SCM_NLONGBITS (&((ulongptr) t->exceptfds)[i]); |
3666451e MD |
332 | } |
333 | cont_except: | |
95f44da9 | 334 | ; |
3666451e MD |
335 | } |
336 | t->retval = n_ones; | |
337 | } | |
338 | ||
a48b6916 MD |
339 | /* Just like finalize_fd_sets except that we don't have to update the |
340 | global fd sets. Those will be recalulated elsewhere. */ | |
341 | static void | |
342 | finalize_fd_sets_lazily (coop_t *t) | |
343 | { | |
344 | int i = (t->nfds + SCM_BITS_PER_LONG - 1) / SCM_BITS_PER_LONG; | |
345 | int n_ones = 0; | |
a48b6916 MD |
346 | while (i > 0) |
347 | { | |
348 | --i; | |
3237b129 | 349 | if (t->readfds != NULL && ((ulongptr) t->readfds)[i] != 0) |
a48b6916 MD |
350 | { |
351 | ((ulongptr) t->readfds)[i] &= ((ulongptr) &rreadfds)[i]; | |
352 | n_ones += SCM_NLONGBITS (&((ulongptr) t->readfds)[i]); | |
353 | } | |
3237b129 | 354 | if (t->writefds != NULL && ((ulongptr) t->writefds)[i] != 0) |
a48b6916 MD |
355 | { |
356 | ((ulongptr) t->writefds)[i] &= ((ulongptr) &rwritefds)[i]; | |
357 | n_ones += SCM_NLONGBITS (&((ulongptr) t->writefds)[i]); | |
358 | } | |
3237b129 | 359 | if (t->exceptfds != NULL && ((ulongptr) t->exceptfds)[i] != 0) |
a48b6916 MD |
360 | { |
361 | ((ulongptr) t->exceptfds)[i] &= ((ulongptr) &rexceptfds)[i]; | |
362 | n_ones += SCM_NLONGBITS (&((ulongptr) t->exceptfds)[i]); | |
363 | } | |
364 | } | |
365 | t->retval = n_ones; | |
366 | } | |
367 | ||
368 | /* Return first fd with a non-zero bit in any of the result sets. */ | |
3666451e MD |
369 | static int |
370 | first_interesting_fd (void) | |
371 | { | |
372 | int i = 0; | |
373 | SELECT_TYPE *s; | |
374 | while (1) | |
375 | { | |
376 | if (((ulongptr) &rreadfds)[i] != 0) | |
377 | { | |
378 | s = &rreadfds; | |
379 | break; | |
380 | } | |
381 | if (((ulongptr) &rwritefds)[i] != 0) | |
382 | { | |
383 | s = &rwritefds; | |
384 | break; | |
385 | } | |
386 | if (((ulongptr) &rexceptfds)[i] != 0) | |
387 | { | |
388 | s = &rexceptfds; | |
389 | break; | |
390 | } | |
391 | ++i; | |
392 | } | |
393 | i *= SCM_BITS_PER_LONG; | |
394 | while (i < gnfds) | |
395 | { | |
396 | if (FD_ISSET (i, s)) | |
397 | return i; | |
398 | ++i; | |
399 | } | |
400 | fprintf (stderr, "first_interesting_fd: internal error\n"); | |
401 | exit (1); | |
402 | } | |
403 | ||
a48b6916 | 404 | /* Revive all threads with an error status. */ |
c69dfa65 MD |
405 | void |
406 | scm_error_revive_threads (void) | |
3666451e MD |
407 | { |
408 | coop_t *t; | |
409 | ||
410 | while ((t = coop_qget (&coop_global_sleepq)) != NULL) | |
411 | { | |
c44bfbc9 | 412 | t->_errno = errno; |
3666451e | 413 | t->retval = -1; |
c69dfa65 MD |
414 | if (t != coop_global_curr) |
415 | coop_qput (&coop_global_runq, t); | |
3666451e | 416 | } |
c69dfa65 | 417 | collisionp = 0; |
3666451e MD |
418 | gnfds = 0; |
419 | FD_ZERO (&greadfds); | |
420 | FD_ZERO (&gwritefds); | |
421 | FD_ZERO (&gexceptfds); | |
422 | } | |
423 | ||
a48b6916 MD |
424 | /* Given the result of a call to safe_select and the current time, |
425 | try to wake up some threads and return the first one. Return NULL | |
426 | if we couldn't find any. */ | |
3666451e | 427 | static coop_t * |
c69dfa65 | 428 | find_thread (int n, struct timeval *now, int sleepingp) |
3666451e MD |
429 | { |
430 | coop_t *t; | |
431 | int fd; | |
432 | ||
c69dfa65 MD |
433 | if (n < 0) |
434 | /* An error or a signal has occured. Wake all threads. Since we | |
435 | don't care to calculate if there is a sinner we report the | |
436 | error to all of them. */ | |
437 | { | |
438 | scm_error_revive_threads (); | |
439 | if (!scm_I_am_dead) | |
440 | return coop_global_curr; | |
441 | } | |
442 | else if (n == 0) | |
3666451e MD |
443 | { |
444 | while (!QEMPTYP (coop_global_sleepq) | |
445 | && (t = QFIRST (coop_global_sleepq))->timeoutp | |
446 | && (t->wakeup_time.tv_sec < now->tv_sec | |
447 | || (t->wakeup_time.tv_sec == now->tv_sec | |
448 | && t->wakeup_time.tv_usec <= now->tv_usec))) | |
449 | { | |
450 | coop_qget (&coop_global_sleepq); | |
a48b6916 MD |
451 | if (collisionp) |
452 | finalize_fd_sets_lazily (t); | |
453 | else | |
454 | finalize_fd_sets (t); | |
3666451e MD |
455 | coop_qput (&coop_global_runq, t); |
456 | } | |
a48b6916 MD |
457 | if (collisionp) |
458 | { | |
459 | while ((t = coop_qget (&coop_global_sleepq)) != NULL) | |
460 | coop_qput (&coop_tmp_queue, t); | |
461 | goto rebuild_global_fd_sets; | |
462 | } | |
3666451e MD |
463 | } |
464 | else if (n > 0) | |
465 | { | |
466 | /* Find the first interesting file descriptor */ | |
467 | fd = first_interesting_fd (); | |
468 | /* Check the sleeping queue for this file descriptor. | |
469 | Other file descriptors will be handled next time | |
470 | coop_next_runnable_thread is called. */ | |
471 | /* This code is inefficient. We'll improve it later. */ | |
472 | while ((t = coop_qget (&coop_global_sleepq)) != NULL) | |
473 | { | |
474 | if ((t->readfds && FD_ISSET (fd, t->readfds)) | |
475 | || (t->writefds && FD_ISSET (fd, t->writefds)) | |
476 | || (t->exceptfds && FD_ISSET (fd, t->exceptfds)) | |
477 | || (t->timeoutp | |
478 | && (t->wakeup_time.tv_sec < now->tv_sec | |
479 | || (t->wakeup_time.tv_sec == now->tv_sec | |
480 | && t->wakeup_time.tv_usec <= now->tv_usec)))) | |
481 | { | |
a48b6916 MD |
482 | if (collisionp) |
483 | finalize_fd_sets_lazily (t); | |
484 | else | |
485 | finalize_fd_sets (t); | |
3666451e MD |
486 | coop_qput (&coop_global_runq, t); |
487 | } | |
488 | else | |
489 | coop_qput(&coop_tmp_queue, t); | |
490 | } | |
a48b6916 MD |
491 | if (collisionp) |
492 | { | |
493 | rebuild_global_fd_sets: | |
494 | collisionp = 0; | |
495 | gnfds = 0; | |
496 | FD_ZERO (&greadfds); | |
497 | FD_ZERO (&gwritefds); | |
498 | FD_ZERO (&gexceptfds); | |
499 | while ((t = coop_qget (&coop_tmp_queue)) != NULL) | |
500 | { | |
501 | add_fd_sets (t); | |
502 | coop_qput (&coop_global_sleepq, t); | |
503 | } | |
504 | } | |
505 | else | |
506 | { | |
507 | while ((t = coop_qget (&coop_tmp_queue)) != NULL) | |
508 | coop_qput (&coop_global_sleepq, t); | |
509 | } | |
3666451e | 510 | } |
3666451e MD |
511 | |
512 | return coop_qget (&coop_global_runq); | |
513 | } | |
514 | ||
515 | /* Return next runnable thread on the run queue. | |
516 | * First update the queue with possible I/O or timeouts. | |
517 | * If no thread is found, return NULL. | |
518 | */ | |
519 | coop_t * | |
520 | coop_next_runnable_thread () | |
521 | { | |
81e81a5c | 522 | coop_t *t; |
3666451e MD |
523 | struct timeval now; |
524 | int n; | |
525 | ||
526 | /* Just return next thread on the runq if the sleepq is empty. */ | |
527 | if (QEMPTYP (coop_global_sleepq)) | |
c69dfa65 MD |
528 | { |
529 | if (QEMPTYP (coop_global_runq)) | |
530 | return coop_global_curr; | |
531 | else | |
532 | return coop_qget (&coop_global_runq); | |
533 | } | |
3666451e MD |
534 | |
535 | if (gnfds > 0) | |
536 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, &timeout0); | |
537 | else | |
538 | n = 0; | |
539 | if (QFIRST (coop_global_sleepq)->timeoutp) | |
540 | { | |
541 | gettimeofday (&now, NULL); | |
c69dfa65 | 542 | t = find_thread (n, &now, 0); |
3666451e | 543 | } |
81e81a5c | 544 | else |
c69dfa65 MD |
545 | t = find_thread (n, 0, 0); |
546 | return t == NULL ? coop_global_curr : t; | |
3666451e MD |
547 | } |
548 | ||
549 | coop_t * | |
550 | coop_wait_for_runnable_thread_now (struct timeval *now) | |
551 | { | |
552 | int n; | |
553 | coop_t *t; | |
554 | ||
555 | if (gnfds > 0) | |
556 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, &timeout0); | |
557 | else | |
558 | n = 0; | |
559 | /* Is there any other runnable thread? */ | |
c69dfa65 | 560 | t = find_thread (n, now, 1); |
3666451e MD |
561 | while (t == NULL) |
562 | { | |
563 | /* No. Let the process go to sleep. */ | |
564 | if ((t = QFIRST (coop_global_sleepq))->timeoutp) | |
565 | { | |
566 | now->tv_sec = t->wakeup_time.tv_sec - now->tv_sec; | |
567 | if (now->tv_usec > t->wakeup_time.tv_usec) | |
568 | { | |
569 | --now->tv_sec; | |
570 | now->tv_usec = 1000000 + t->wakeup_time.tv_usec - now->tv_usec; | |
571 | } | |
572 | else | |
573 | now->tv_usec = t->wakeup_time.tv_usec - now->tv_usec; | |
574 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, now); | |
575 | } | |
576 | else | |
577 | n = safe_select (gnfds, &greadfds, &gwritefds, &gexceptfds, NULL); | |
578 | gettimeofday (now, NULL); | |
c69dfa65 | 579 | t = find_thread (n, now, 1); |
3666451e MD |
580 | } |
581 | ||
582 | return t; | |
583 | } | |
584 | ||
585 | coop_t * | |
586 | coop_wait_for_runnable_thread () | |
587 | { | |
588 | struct timeval now; | |
589 | ||
590 | if (QEMPTYP (coop_global_sleepq)) | |
c69dfa65 MD |
591 | { |
592 | if (QEMPTYP (coop_global_runq)) | |
593 | return coop_global_curr; | |
594 | else | |
595 | return coop_qget (&coop_global_runq); | |
596 | } | |
3666451e MD |
597 | |
598 | if (QFIRST (coop_global_sleepq)->timeoutp) | |
599 | gettimeofday (&now, NULL); | |
600 | ||
601 | return coop_wait_for_runnable_thread_now (&now); | |
602 | } | |
603 | ||
1cbf4dea MD |
604 | /* Initialize bit counting array */ |
605 | static void init_bc (int bit, int i, int n) | |
606 | { | |
607 | if (bit == 0) | |
608 | bc[i] = n; | |
609 | else | |
610 | { | |
611 | init_bc (bit >> 1, i, n); | |
612 | init_bc (bit >> 1, i | bit, n + 1); | |
613 | } | |
614 | } | |
615 | ||
616 | void | |
617 | scm_init_iselect () | |
618 | { | |
619 | #if 0 /* This is just symbolic */ | |
620 | collisionp = 0; | |
621 | gnfds = 0; | |
622 | FD_ZERO (&greadfds); | |
623 | FD_ZERO (&gwritefds); | |
624 | FD_ZERO (&gexceptfds); | |
625 | timeout0.tv_sec = 0; | |
626 | timeout0.tv_usec = 0; | |
627 | #endif | |
628 | init_bc (0x80, 0, 0); | |
8dc9439f | 629 | #ifndef SCM_MAGIC_SNARFER |
a0599745 | 630 | #include "libguile/iselect.x" |
8dc9439f | 631 | #endif |
1cbf4dea MD |
632 | } |
633 | ||
634 | #endif /* GUILE_ISELECT */ | |
635 | ||
3666451e MD |
636 | int |
637 | scm_internal_select (int nfds, | |
638 | SELECT_TYPE *readfds, | |
639 | SELECT_TYPE *writefds, | |
640 | SELECT_TYPE *exceptfds, | |
641 | struct timeval *timeout) | |
642 | { | |
1cbf4dea MD |
643 | #ifndef GUILE_ISELECT |
644 | int res = select (nfds, readfds, writefds, exceptfds, timeout); | |
645 | SCM_ASYNC_TICK; | |
646 | return res; | |
647 | #else /* GUILE_ISELECT */ | |
3666451e MD |
648 | struct timeval now; |
649 | coop_t *t, *curr = coop_global_curr; | |
c69dfa65 | 650 | |
3666451e MD |
651 | /* If the timeout is 0, we're polling and can handle it quickly. */ |
652 | if (timeout != NULL | |
653 | && timeout->tv_sec == 0 | |
654 | && timeout->tv_usec == 0) | |
655 | return select (nfds, readfds, writefds, exceptfds, timeout); | |
656 | ||
c69dfa65 | 657 | SCM_DEFER_INTS; |
c718cb07 | 658 | |
3666451e | 659 | /* Add our file descriptor flags to the common set. */ |
3237b129 MD |
660 | curr->nfds = nfds; |
661 | curr->readfds = readfds; | |
662 | curr->writefds = writefds; | |
663 | curr->exceptfds = exceptfds; | |
664 | add_fd_sets (curr); | |
3666451e MD |
665 | |
666 | /* Place ourselves on the sleep queue and get a new thread to run. */ | |
667 | if (timeout == NULL) | |
668 | { | |
669 | curr->timeoutp = 0; | |
670 | coop_qput (&coop_global_sleepq, curr); | |
671 | t = coop_wait_for_runnable_thread (); | |
672 | } | |
673 | else | |
674 | { | |
675 | gettimeofday (&now, NULL); | |
676 | curr->timeoutp = 1; | |
677 | curr->wakeup_time.tv_sec = now.tv_sec + timeout->tv_sec; | |
678 | curr->wakeup_time.tv_usec = now.tv_usec + timeout->tv_usec; | |
679 | if (curr->wakeup_time.tv_usec >= 1000000) | |
680 | { | |
681 | ++curr->wakeup_time.tv_sec; | |
682 | curr->wakeup_time.tv_usec -= 1000000; | |
683 | } | |
684 | /* Insert the current thread at the right place in the sleep queue */ | |
685 | coop_timeout_qinsert (&coop_global_sleepq, curr); | |
686 | t = coop_wait_for_runnable_thread_now (&now); | |
687 | } | |
688 | ||
689 | /* If the new thread is the same as the sleeping thread, do nothing */ | |
c69dfa65 | 690 | if (t != coop_global_curr) |
3666451e MD |
691 | { |
692 | /* Do a context switch. */ | |
693 | coop_global_curr = t; | |
694 | QT_BLOCK (coop_sleephelp, curr, NULL, t->sp); | |
695 | } | |
696 | ||
c69dfa65 MD |
697 | if (coop_global_curr->retval == -1) |
698 | errno = coop_global_curr->_errno; | |
699 | SCM_ALLOW_INTS; | |
1cbf4dea | 700 | SCM_ASYNC_TICK; |
c69dfa65 | 701 | return coop_global_curr->retval; |
1cbf4dea | 702 | #endif /* GUILE_ISELECT */ |
3666451e | 703 | } |
89e00824 ML |
704 | |
705 | /* | |
706 | Local Variables: | |
707 | c-file-style: "gnu" | |
708 | End: | |
709 | */ |