rpoll.c revision 135768
1/* 2 * Copyright (c)1996-2002 by Hartmut Brandt 3 * All rights reserved. 4 * 5 * Author: Hartmut Brandt 6 * 7 * Redistribution of this software and documentation and use in source and 8 * binary forms, with or without modification, are permitted provided that 9 * the following conditions are met: 10 * 11 * 1. Redistributions of source code or documentation must retain the above 12 * copyright notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE AND DOCUMENTATION IS PROVIDED BY THE AUTHOR 18 * AND ITS CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 19 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 20 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 21 * THE AUTHOR OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 24 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 25 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 26 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 27 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29/* 30 * These functions try to hide the poll/select/setitimer interface from the 31 * user. You associate callback functions with file descriptors and timers. 32 * 33 * $Begemot: libbegemot/rpoll.c,v 1.14 2004/09/21 15:59:00 brandt Exp $ 34 */ 35# include <stdio.h> 36# include <stdlib.h> 37# include <stddef.h> 38# include <stdarg.h> 39# include <signal.h> 40# include <string.h> 41# include <errno.h> 42# include <time.h> 43# include <assert.h> 44# include <unistd.h> 45# include <sys/time.h> 46 47/* 48 * There happens to be linuxes which read siginfo.h when including 49 * signal.h, which, for no appearent reason, defines these symbols. 50 */ 51# ifdef POLL_IN 52# undef POLL_IN 53# endif 54# ifdef POLL_OUT 55# undef POLL_OUT 56# endif 57 58# include "rpoll.h" 59 60/* 61# define DEBUG 62*/ 63 64# ifdef USE_POLL 65# ifdef NEED_POLL_XOPEN_TWIDDLE 66# define __USE_XOPEN 67# endif 68# include <poll.h> 69# ifdef NEED_POLL_XOPEN_TWIDDLE 70# undef __USE_XOPEN 71# endif 72# include <stropts.h> 73# endif 74 75/* 76 * the second define is for Linux, which sometimes fails to 77 * declare INFTIM. 78 */ 79# if defined(USE_SELECT) || !defined(INFTIM) 80# define INFTIM (-1) 81# endif 82 83# if defined(SIGPOLL) 84# define SIGNAL SIGPOLL 85# else 86# if defined(SIGIO) 87# define SIGNAL SIGIO 88# endif 89# endif 90 91# ifdef USE_POLL 92# define poll_in (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI) 93# define poll_out (POLLOUT | POLLWRNORM | POLLWRBAND) 94# define poll_except (POLLERR | POLLHUP) 95# endif 96 97# ifdef BROKEN_SELECT_PROTO 98# define SELECT_CAST(P) (int *)P 99# else 100# define SELECT_CAST(P) P 101# endif 102 103 104typedef signed long long tval_t; 105 106static inline tval_t GETMSECS(void); 107 108static inline tval_t 109GETMSECS(void) { 110 struct timeval tval; 111 112 (void)gettimeofday(&tval, NULL); 113 return (tval_t)tval.tv_sec*1000+tval.tv_usec/1000; 114} 115 116/* 117 * Simple fatal exit. 118 */ 119static void 120_panic(const char *fmt, ...) 121{ 122 va_list ap; 123 124 va_start(ap, fmt); 125 fprintf(stderr, "panic: "); 126 vfprintf(stderr, fmt, ap); 127 fprintf(stderr, "\n"); 128 va_end(ap); 129 130 exit(1); 131} 132 133static void * 134_xrealloc(void *p, size_t s) 135{ 136 void *ptr; 137 138 if(p == NULL) { 139 if((ptr=malloc(s)) == NULL && (s!=0 || (ptr=malloc(1)) == NULL)) 140 _panic("out of memory: xrealloc(%lx, %lu)", 141 (unsigned long)p, (unsigned long)s); 142 } else if(s == 0) { 143 free(p); 144 if((ptr=malloc(s)) == NULL && (ptr=malloc(1)) == NULL) 145 _panic("out of memory: xrealloc(%lx, %lu)", 146 (unsigned long)p, (unsigned long)s); 147 } else { 148 if((ptr = realloc(p, s)) == NULL) 149 _panic("out of memory: xrealloc(%lx, %lu)", 150 (unsigned long)p, (unsigned long)s); 151 } 152 153 return ptr; 154} 155 156/* 157 * This structure holds one registration record for files 158 */ 159typedef struct { 160 int fd; /* file descriptor (-1 if struct unused) */ 161 int mask; /* event flags */ 162 void * arg; /* client arg */ 163 poll_f func; /* handler */ 164# ifdef USE_POLL 165 struct pollfd *pfd; /* pointer to corresponding poll() structure */ 166# endif 167} PollReg_t; 168 169/* 170 * Now for timers 171 */ 172typedef struct { 173 u_int msecs; /* millisecond value of the timer */ 174 int repeat; /* one shot or repeat? */ 175 void *arg; /* client arg */ 176 timer_f func; /* handler, 0 means disfunct */ 177 tval_t when; /* next time to trigger in msecs! */ 178} PollTim_t; 179 180/* how many records should our table grow at once? */ 181# define POLL_REG_GROW 100 182 183# ifdef USE_POLL 184static struct pollfd * pfd; /* fd list for poll() */ 185# endif 186 187# ifdef USE_SELECT 188static fd_set rset, wset, xset; /* file descriptor sets for select() */ 189static int maxfd; /* maximum fd number */ 190# endif 191 192static int in_dispatch; 193 194static PollReg_t * regs; /* registration records */ 195static u_int regs_alloc; /* how many are allocated */ 196static u_int regs_used; /* upper used limit */ 197static sigset_t bset; /* blocked signals */ 198static int rebuild; /* rebuild table on next dispatch() */ 199 200static int * tfd; /* sorted entries */ 201static u_int tfd_alloc; /* number of entries allocated */ 202static u_int tfd_used; /* number of entries used */ 203static PollTim_t * tims; /* timer registration records */ 204static u_int tims_alloc; /* how many are allocated */ 205static u_int tims_used; /* how many are used */ 206static int resort; /* resort on next dispatch */ 207 208int rpoll_trace; 209int rpoll_policy; /* if 0 start sched callbacks from 0 else try round robin */ 210 211static void poll_build(void); 212static void poll_blocksig(void); 213static void poll_unblocksig(void); 214static void sort_timers(void); 215 216 217/* 218 * Private function to block SIGPOLL or SIGIO for a short time. 219 * Don't forget to call poll_unblock before return from the calling function. 220 * Don't change the mask between this calls (your changes will be lost). 221 */ 222static void 223poll_blocksig(void) 224{ 225 sigset_t set; 226 227 sigemptyset(&set); 228 sigaddset(&set, SIGNAL); 229 230 if(sigprocmask(SIG_BLOCK, &set, &bset)) 231 _panic("sigprocmask(SIG_BLOCK): %s", strerror(errno)); 232} 233 234/* 235 * unblock the previously blocked signal 236 */ 237static void 238poll_unblocksig(void) 239{ 240 if(sigprocmask(SIG_SETMASK, &bset, NULL)) 241 _panic("sigprocmask(SIG_SETMASK): %s", strerror(errno)); 242} 243 244/* 245 * Register the file descriptor fd. If the event corresponding to 246 * mask arrives func is called with arg. 247 * If fd is already registered with that func and arg, only the mask 248 * is changed. 249 * We block the IO-signal, so the dispatch function can be called from 250 * within the signal handler. 251 */ 252int 253poll_register(int fd, poll_f func, void *arg, int mask) 254{ 255 PollReg_t * p; 256 257 poll_blocksig(); 258 259 /* already registered? */ 260 for(p = regs; p < ®s[regs_alloc]; p++) 261 if(p->fd == fd && p->func == func && p->arg == arg) { 262 p->mask = mask; 263 break; 264 } 265 266 if(p == ®s[regs_alloc]) { 267 /* no - register */ 268 269 /* find a free slot */ 270 for(p = regs; p < ®s[regs_alloc]; p++) 271 if(p->fd == -1) 272 break; 273 274 if(p == ®s[regs_alloc]) { 275 size_t newsize = regs_alloc + POLL_REG_GROW; 276 regs = _xrealloc(regs, sizeof(regs[0]) * newsize); 277 for(p = ®s[regs_alloc]; p < ®s[newsize]; p++) { 278 p->fd = -1; 279# ifdef USE_POLL 280 p->pfd = NULL; 281# endif 282 } 283 p = ®s[regs_alloc]; 284 regs_alloc = newsize; 285 } 286 287 p->fd = fd; 288 p->arg = arg; 289 p->mask = mask; 290 p->func = func; 291 292 regs_used++; 293 rebuild = 1; 294 } 295 296 poll_unblocksig(); 297 298 if(rpoll_trace) 299 fprintf(stderr, "poll_register(%d, %#lx, %#lx, %#x)->%d", 300 fd, (u_long)func, (u_long)arg, mask, p - regs); 301 return p - regs; 302} 303 304/* 305 * remove registration 306 */ 307void 308poll_unregister(int handle) 309{ 310 if(rpoll_trace) 311 fprintf(stderr, "poll_unregister(%d)", handle); 312 313 poll_blocksig(); 314 315 regs[handle].fd = -1; 316# ifdef USE_POLL 317 regs[handle].pfd = NULL; 318# endif 319 rebuild = 1; 320 regs_used--; 321 322 poll_unblocksig(); 323} 324 325/* 326 * Build the structures used by poll() or select() 327 */ 328static void 329poll_build(void) 330{ 331 PollReg_t * p; 332 333# ifdef USE_POLL 334 struct pollfd * f; 335 336 f = pfd = _xrealloc(pfd, sizeof(pfd[0]) * regs_used); 337 338 for(p = regs; p < ®s[regs_alloc]; p++) 339 if(p->fd >= 0) { 340 f->fd = p->fd; 341 f->events = 0; 342 if(p->mask & POLL_IN) 343 f->events |= poll_in; 344 if(p->mask & POLL_OUT) 345 f->events |= poll_out; 346 if(p->mask & POLL_EXCEPT) 347 f->events |= poll_except; 348 f->revents = 0; 349 p->pfd = f++; 350 } 351 assert(f == &pfd[regs_used]); 352# endif 353 354# ifdef USE_SELECT 355 FD_ZERO(&rset); 356 FD_ZERO(&wset); 357 FD_ZERO(&xset); 358 maxfd = -1; 359 for(p = regs; p < ®s[regs_alloc]; p++) 360 if(p->fd >= 0) { 361 if(p->fd > maxfd) 362 maxfd = p->fd; 363 if(p->mask & POLL_IN) 364 FD_SET(p->fd, &rset); 365 if(p->mask & POLL_OUT) 366 FD_SET(p->fd, &wset); 367 if(p->mask & POLL_EXCEPT) 368 FD_SET(p->fd, &xset); 369 } 370# endif 371} 372 373int 374poll_start_timer(u_int msecs, int repeat, timer_f func, void *arg) 375{ 376 PollTim_t *p; 377 378 /* find unused entry */ 379 for(p = tims; p < &tims[tims_alloc]; p++) 380 if(p->func == NULL) 381 break; 382 383 if(p == &tims[tims_alloc]) { 384 if(tims_alloc == tims_used) { 385 size_t newsize = tims_alloc + POLL_REG_GROW; 386 tims = _xrealloc(tims, sizeof(tims[0]) * newsize); 387 for(p = &tims[tims_alloc]; p < &tims[newsize]; p++) 388 p->func = NULL; 389 p = &tims[tims_alloc]; 390 tims_alloc = newsize; 391 } 392 } 393 394 /* create entry */ 395 p->msecs = msecs; 396 p->repeat = repeat; 397 p->arg = arg; 398 p->func = func; 399 p->when = GETMSECS() + msecs; 400 401 tims_used++; 402 403 resort = 1; 404 405 if(rpoll_trace) 406 fprintf(stderr, "poll_start_timer(%u, %d, %#lx, %#lx)->%u", 407 msecs, repeat, (u_long)func, (u_long)arg, p - tims); 408 409 return p - tims; 410} 411 412/* 413 * Here we have to look into the sorted table, whether any entry there points 414 * into the registration table for the deleted entry. This is needed, 415 * because a unregistration can occure while we are scanning through the 416 * table in dispatch(). Do this only, if we are really there - resorting 417 * will sort out things if we are called from outside the loop. 418 */ 419void 420poll_stop_timer(int handle) 421{ 422 u_int i; 423 424 if(rpoll_trace) 425 fprintf(stderr, "poll_stop_timer(%d)", handle); 426 427 tims[handle].func = NULL; 428 tims_used--; 429 430 resort = 1; 431 432 if(!in_dispatch) 433 return; 434 435 for(i = 0; i < tfd_used; i++) 436 if(tfd[i] == handle) { 437 tfd[i] = -1; 438 break; 439 } 440} 441 442/* 443 * Squeeze and sort timer table. 444 * Should perhaps use a custom sort. 445 */ 446static int 447tim_cmp(const void *p1, const void *p2) 448{ 449 int t1 = *(const int *)p1; 450 int t2 = *(const int *)p2; 451 452 return tims[t1].when < tims[t2].when ? -1 453 : tims[t1].when > tims[t2].when ? +1 454 : 0; 455} 456 457/* 458 * Reconstruct the tfd-array. This will be an sorted array of indexes 459 * to the used entries in tims. The next timer to expire will be infront 460 * of the array. tfd_used is the number of used entries. The array is 461 * re-allocated if needed. 462 */ 463static void 464sort_timers(void) 465{ 466 int *pp; 467 u_int i; 468 469 if(tims_used > tfd_alloc) { 470 tfd_alloc = tims_used; 471 tfd = _xrealloc(tfd, sizeof(int *) * tfd_alloc); 472 } 473 474 pp = tfd; 475 476 for(i = 0; i < tims_alloc; i++) 477 if(tims[i].func) 478 *pp++ = i; 479 assert(pp - tfd == (ptrdiff_t)tims_used); 480 481 tfd_used = tims_used; 482 if(tfd_used > 1) 483 qsort(tfd, tfd_used, sizeof(int), tim_cmp); 484} 485 486/* 487 * Poll the file descriptors and dispatch to the right function 488 * If wait is true the poll blocks until somewhat happens. 489 * Don't use a pointer here, because the called function may cause 490 * a reallocation! The check for pfd != NULL is required, because 491 * a sequence of unregister/register could make the wrong callback 492 * to be called. So we clear pfd in unregister and check here. 493 */ 494void 495poll_dispatch(int wait) 496{ 497 u_int i, idx; 498 int ret; 499 tval_t now; 500 int tout; 501 static u_int last_index; 502 503# ifdef USE_SELECT 504 fd_set nrset, nwset, nxset; 505 struct timeval tv; 506# endif 507 508 in_dispatch = 1; 509 510 if(rebuild) { 511 rebuild = 0; 512 poll_build(); 513 } 514 if(resort) { 515 resort = 0; 516 sort_timers(); 517 } 518 519 /* in wait mode - compute the timeout */ 520 if(wait) { 521 if(tfd_used) { 522 now = GETMSECS(); 523# ifdef DEBUG 524 { 525 fprintf(stderr, "now=%"QUADFMT"u", now); 526 for(i = 0; i < tims_used; i++) 527 fprintf(stderr, "timers[%2d] = %"QUADFMT"d", i, tfd[i]->when - now); 528 } 529# endif 530 if((tout = tims[tfd[0]].when - now) < 0) 531 tout = 0; 532 } else 533 tout = INFTIM; 534 } else 535 tout = 0; 536 537# ifdef DEBUG 538 fprintf(stderr, "rpoll -- selecting with tout=%u", tout); 539# endif 540 541# ifdef USE_POLL 542 ret = poll(pfd, regs_used, tout); 543# endif 544 545# ifdef USE_SELECT 546 nrset = rset; 547 nwset = wset; 548 nxset = xset; 549 if(tout != INFTIM) { 550 tv.tv_sec = tout / 1000; 551 tv.tv_usec = (tout % 1000) * 1000; 552 } 553 ret = select(maxfd+1, 554 SELECT_CAST(&nrset), 555 SELECT_CAST(&nwset), 556 SELECT_CAST(&nxset), (tout==INFTIM) ? 0 : &tv); 557# endif 558 559 if(ret == -1) { 560 if(errno == EINTR) 561 return; 562 _panic("poll/select: %s", strerror(errno)); 563 } 564 565 /* dispatch files */ 566 if(ret > 0) { 567 for(i = 0; i < regs_alloc; i++) { 568 idx = rpoll_policy ? ((last_index+i) % regs_alloc) : i; 569 570 assert(idx < regs_alloc); 571 572 if(regs[idx].fd >= 0) { 573 int mask = 0; 574 575# ifdef USE_POLL 576 if(regs[idx].pfd) { 577 if(regs[idx].pfd->revents & poll_in) 578 mask |= POLL_IN; 579 if(regs[idx].pfd->revents & poll_out) 580 mask |= POLL_OUT; 581 if(regs[idx].pfd->revents & poll_except) 582 mask |= POLL_EXCEPT; 583 } 584# endif 585# ifdef USE_SELECT 586 if(FD_ISSET(regs[idx].fd, &nrset)) 587 mask |= POLL_IN; 588 if(FD_ISSET(regs[idx].fd, &nwset)) 589 mask |= POLL_OUT; 590 if(FD_ISSET(regs[idx].fd, &nxset)) 591 mask |= POLL_EXCEPT; 592# endif 593 assert(idx < regs_alloc); 594 595 if(mask) { 596 if(rpoll_trace) 597 fprintf(stderr, "poll_dispatch() -- " 598 "file %d/%d", 599 regs[idx].fd, idx); 600 (*regs[idx].func)(regs[idx].fd, mask, regs[idx].arg); 601 } 602 } 603 604 } 605 last_index++; 606 } 607 608 /* dispatch timeouts */ 609 if(tfd_used) { 610 now = GETMSECS(); 611 for(i = 0; i < tfd_used; i++) { 612 if(tfd[i] < 0) 613 continue; 614 if(tims[tfd[i]].when > now) 615 break; 616 if(rpoll_trace) 617 fprintf(stderr, "rpoll_dispatch() -- timeout %d",tfd[i]); 618 (*tims[tfd[i]].func)(tfd[i], tims[tfd[i]].arg); 619 if(tfd[i] < 0) 620 continue; 621 if(tims[tfd[i]].repeat) 622 tims[tfd[i]].when = now + tims[tfd[i]].msecs; 623 else { 624 tims[tfd[i]].func = NULL; 625 tims_used--; 626 tfd[i] = -1; 627 } 628 resort = 1; 629 } 630 } 631 in_dispatch = 0; 632} 633 634 635# ifdef TESTME 636struct timeval start, now; 637int t0, t1; 638 639double elaps(void); 640void infunc(int fd, int mask, void *arg); 641 642double 643elaps(void) 644{ 645 gettimeofday(&now, NULL); 646 647 return (double)(10 * now.tv_sec + now.tv_usec / 100000 - 10 * start.tv_sec - start.tv_usec / 100000) 648 / 10; 649} 650 651void 652infunc(int fd, int mask, void *arg) 653{ 654 char buf[1024]; 655 int ret; 656 657 mask = mask; 658 arg = arg; 659 if((ret = read(fd, buf, sizeof(buf))) < 0) 660 _panic("read: %s", strerror(errno)); 661 write(1, "stdin:", 6); 662 write(1, buf, ret); 663} 664 665void tfunc0(int tid, void *arg); 666void tfunc1(int tid, void *arg); 667 668void 669tfunc0(int tid, void *arg) 670{ 671 printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg); 672} 673void 674tfunc1(int tid, void *arg) 675{ 676 printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg); 677} 678 679void first(int tid, void *arg); 680void second(int tid, void *arg); 681 682void 683second(int tid, void *arg) 684{ 685 printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg); 686 poll_start_timer(5500, 0, first, "first"); 687 poll_stop_timer(t1); 688 t0 = poll_start_timer(1000, 1, tfunc0, "1 second"); 689} 690void 691first(int tid, void *arg) 692{ 693 printf("%4.1f -- %d: %s\n", elaps(), tid, (char *)arg); 694 poll_start_timer(3700, 0, second, "second"); 695 poll_stop_timer(t0); 696 t1 = poll_start_timer(250, 1, tfunc1, "1/4 second"); 697} 698 699int 700main(int argc, char *argv[]) 701{ 702 argc = argc; 703 argv = argv; 704 gettimeofday(&start, NULL); 705 poll_register(0, infunc, NULL, POLL_IN); 706 t0 = poll_start_timer(1000, 1, tfunc0, "1 second"); 707 poll_start_timer(2500, 0, first, "first"); 708 709 while(1) 710 poll_dispatch(1); 711 712 return 0; 713} 714# endif 715