src/thttpd-2.27/fdwatch.c

   1 /* fdwatch.c - fd watcher routines, either select() or poll()
   2 **
   3 ** Copyright © 1999,2000 by Jef Poskanzer <jef@mail.acme.com>.
   4 ** All rights reserved.
   5 **
   6 ** Redistribution and use in source and binary forms, with or without
   7 ** modification, are permitted provided that the following conditions
   8 ** are met:
   9 ** 1. Redistributions of source code must retain the above copyright
  10 **    notice, this list of conditions and the following disclaimer.
  11 ** 2. Redistributions in binary form must reproduce the above copyright
  12 **    notice, this list of conditions and the following disclaimer in the
  13 **    documentation and/or other materials provided with the distribution.
  14 **
  15 ** THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18 ** ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21 ** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22 ** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25 ** SUCH DAMAGE.
  26 */
  27
  28 #include <sys/types.h>
  29 #include <stdlib.h>
  30 #include <unistd.h>
  31 #include <string.h>
  32 #include <sys/time.h>
  33 #include <sys/resource.h>
  34 #include <syslog.h>
  35 #include <fcntl.h>
  36
  37 #ifndef MIN
  38 #define MIN(a,b) ((a) < (b) ? (a) : (b))
  39 #endif
  40
  41 #ifdef HAVE_POLL_H
  42 #include <poll.h>
  43 #else /* HAVE_POLL_H */
  44 #ifdef HAVE_SYS_POLL_H
  45 #include <sys/poll.h>
  46 #endif /* HAVE_SYS_POLL_H */
  47 #endif /* HAVE_POLL_H */
  48
  49 #ifdef HAVE_SYS_DEVPOLL_H
  50 #include <sys/devpoll.h>
  51 #ifndef HAVE_DEVPOLL
  52 #define HAVE_DEVPOLL
  53 #endif /* !HAVE_DEVPOLL */
  54 #endif /* HAVE_SYS_DEVPOLL_H */
  55
  56 #ifdef HAVE_SYS_EVENT_H
  57 #include <sys/event.h>
  58 #endif /* HAVE_SYS_EVENT_H */
  59
  60 #include "fdwatch.h"
  61
  62 #ifdef HAVE_SELECT
  63 #ifndef FD_SET
  64 #define NFDBITS         32
  65 #define FD_SETSIZE      32
  66 #define FD_SET(n, p)    ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
  67 #define FD_CLR(n, p)    ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
  68 #define FD_ISSET(n, p)  ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
  69 #define FD_ZERO(p)      bzero((char*)(p), sizeof(*(p)))
  70 #endif /* !FD_SET */
  71 #endif /* HAVE_SELECT */
  72
  73 static int nfiles;
  74 static long nwatches;
  75 static int* fd_rw;
  76 static void** fd_data;
  77 static int nreturned, next_ridx;
  78
  79 #ifdef HAVE_KQUEUE
  80
  81 #define WHICH                  "kevent"
  82 #define INIT( nf )         kqueue_init( nf )
  83 #define ADD_FD( fd, rw )       kqueue_add_fd( fd, rw )
  84 #define DEL_FD( fd )           kqueue_del_fd( fd )
  85 #define WATCH( timeout_msecs ) kqueue_watch( timeout_msecs )
  86 #define CHECK_FD( fd )         kqueue_check_fd( fd )
  87 #define GET_FD( ridx )         kqueue_get_fd( ridx )
  88
  89 static int kqueue_init( int nf );
  90 static void kqueue_add_fd( int fd, int rw );
  91 static void kqueue_del_fd( int fd );
  92 static int kqueue_watch( long timeout_msecs );
  93 static int kqueue_check_fd( int fd );
  94 static int kqueue_get_fd( int ridx );
  95
  96 #else /* HAVE_KQUEUE */
  97 # ifdef HAVE_DEVPOLL
  98
  99 #define WHICH                  "devpoll"
 100 #define INIT( nf )         devpoll_init( nf )
 101 #define ADD_FD( fd, rw )       devpoll_add_fd( fd, rw )
 102 #define DEL_FD( fd )           devpoll_del_fd( fd )
 103 #define WATCH( timeout_msecs ) devpoll_watch( timeout_msecs )
 104 #define CHECK_FD( fd )         devpoll_check_fd( fd )
 105 #define GET_FD( ridx )         devpoll_get_fd( ridx )
 106
 107 static int devpoll_init( int nf );
 108 static void devpoll_add_fd( int fd, int rw );
 109 static void devpoll_del_fd( int fd );
 110 static int devpoll_watch( long timeout_msecs );
 111 static int devpoll_check_fd( int fd );
 112 static int devpoll_get_fd( int ridx );
 113
 114 # else /* HAVE_DEVPOLL */
 115 #  ifdef HAVE_POLL
 116
 117 #define WHICH                  "poll"
 118 #define INIT( nf )         poll_init( nf )
 119 #define ADD_FD( fd, rw )       poll_add_fd( fd, rw )
 120 #define DEL_FD( fd )           poll_del_fd( fd )
 121 #define WATCH( timeout_msecs ) poll_watch( timeout_msecs )
 122 #define CHECK_FD( fd )         poll_check_fd( fd )
 123 #define GET_FD( ridx )         poll_get_fd( ridx )
 124
 125 static int poll_init( int nf );
 126 static void poll_add_fd( int fd, int rw );
 127 static void poll_del_fd( int fd );
 128 static int poll_watch( long timeout_msecs );
 129 static int poll_check_fd( int fd );
 130 static int poll_get_fd( int ridx );
 131
 132 #  else /* HAVE_POLL */
 133 #   ifdef HAVE_SELECT
 134
 135 #define WHICH                  "select"
 136 #define INIT( nf )         select_init( nf )
 137 #define ADD_FD( fd, rw )       select_add_fd( fd, rw )
 138 #define DEL_FD( fd )           select_del_fd( fd )
 139 #define WATCH( timeout_msecs ) select_watch( timeout_msecs )
 140 #define CHECK_FD( fd )         select_check_fd( fd )
 141 #define GET_FD( ridx )         select_get_fd( ridx )
 142
 143 static int select_init( int nf );
 144 static void select_add_fd( int fd, int rw );
 145 static void select_del_fd( int fd );
 146 static int select_watch( long timeout_msecs );
 147 static int select_check_fd( int fd );
 148 static int select_get_fd( int ridx );
 149
 150 #   endif /* HAVE_SELECT */
 151 #  endif /* HAVE_POLL */
 152 # endif /* HAVE_DEVPOLL */
 153 #endif /* HAVE_KQUEUE */
 154
 155
 156 /* Routines. */
 157
 158 /* Figure out how many file descriptors the system allows, and
 159 ** initialize the fdwatch data structures.  Returns -1 on failure.
 160 */
 161 int
 162 fdwatch_get_nfiles( void )
 163     {
 164     int i;
 165 #ifdef RLIMIT_NOFILE
 166     struct rlimit rl;
 167 #endif /* RLIMIT_NOFILE */
 168
 169     /* Figure out how many fd's we can have. */
 170     nfiles = getdtablesize();
 171 #ifdef RLIMIT_NOFILE
 172     /* If we have getrlimit(), use that, and attempt to raise the limit. */
 173     if ( getrlimit( RLIMIT_NOFILE, &rl ) == 0 )
 174         {
 175         nfiles = rl.rlim_cur;
 176         if ( rl.rlim_max == RLIM_INFINITY )
 177             rl.rlim_cur = 8192;         /* arbitrary */
 178         else if ( rl.rlim_max > rl.rlim_cur )
 179             rl.rlim_cur = rl.rlim_max;
 180         if ( setrlimit( RLIMIT_NOFILE, &rl ) == 0 )
 181             nfiles = rl.rlim_cur;
 182         }
 183 #endif /* RLIMIT_NOFILE */
 184
 185 #if defined(HAVE_SELECT) && ! ( defined(HAVE_POLL) || defined(HAVE_DEVPOLL) || defined(HAVE_KQUEUE) )
 186     /* If we use select(), then we must limit ourselves to FD_SETSIZE. */
 187     nfiles = MIN( nfiles, FD_SETSIZE );
 188 #endif /* HAVE_SELECT && ! ( HAVE_POLL || HAVE_DEVPOLL || HAVE_KQUEUE ) */
 189
 190     /* Initialize the fdwatch data structures. */
 191     nwatches = 0;
 192     fd_rw = (int*) malloc( sizeof(int) * nfiles );
 193     fd_data = (void**) malloc( sizeof(void*) * nfiles );
 194     if ( fd_rw == (int*) 0 || fd_data == (void**) 0 )
 195         return -1;
 196     for ( i = 0; i < nfiles; ++i )
 197         fd_rw[i] = -1;
 198     if ( INIT( nfiles ) == -1 )
 199         return -1;
 200
 201     return nfiles;
 202     }
 203
 204
 205 /* Add a descriptor to the watch list.  rw is either FDW_READ or FDW_WRITE.  */
 206 void
 207 fdwatch_add_fd( int fd, void* client_data, int rw )
 208     {
 209     if ( fd < 0 || fd >= nfiles || fd_rw[fd] != -1 )
 210         {
 211         syslog( LOG_ERR, "bad fd (%d) passed to fdwatch_add_fd!", fd );
 212         return;
 213         }
 214     ADD_FD( fd, rw );
 215     fd_rw[fd] = rw;
 216     fd_data[fd] = client_data;
 217     }
 218
 219
 220 /* Remove a descriptor from the watch list. */
 221 void
 222 fdwatch_del_fd( int fd )
 223     {
 224     if ( fd < 0 || fd >= nfiles || fd_rw[fd] == -1 )
 225         {
 226         syslog( LOG_ERR, "bad fd (%d) passed to fdwatch_del_fd!", fd );
 227         return;
 228         }
 229     DEL_FD( fd );
 230     fd_rw[fd] = -1;
 231     fd_data[fd] = (void*) 0;
 232     }
 233
 234 /* Do the watch.  Return value is the number of descriptors that are ready,
 235 ** or 0 if the timeout expired, or -1 on errors.  A timeout of INFTIM means
 236 ** wait indefinitely.
 237 */
 238 int
 239 fdwatch( long timeout_msecs )
 240     {
 241     ++nwatches;
 242     nreturned = WATCH( timeout_msecs );
 243     next_ridx = 0;
 244     return nreturned;
 245     }
 246
 247
 248 /* Check if a descriptor was ready. */
 249 int
 250 fdwatch_check_fd( int fd )
 251     {
 252     if ( fd < 0 || fd >= nfiles || fd_rw[fd] == -1 )
 253         {
 254         syslog( LOG_ERR, "bad fd (%d) passed to fdwatch_check_fd!", fd );
 255         return 0;
 256         }
 257     return CHECK_FD( fd );
 258     }
 259
 260
 261 void*
 262 fdwatch_get_next_client_data( void )
 263     {
 264     int fd;
 265
 266     if ( next_ridx >= nreturned )
 267         return (void*) -1;
 268     fd = GET_FD( next_ridx++ );
 269     if ( fd < 0 || fd >= nfiles )
 270         return (void*) 0;
 271     return fd_data[fd];
 272     }
 273
 274
 275 /* Generate debugging statistics syslog message. */
 276 void
 277 fdwatch_logstats( long secs )
 278     {
 279     if ( secs > 0 )
 280         syslog(
 281             LOG_NOTICE, "  fdwatch - %ld %ss (%g/sec)",
 282             nwatches, WHICH, (float) nwatches / secs );
 283     nwatches = 0;
 284     }
 285
 286
 287 #ifdef HAVE_KQUEUE
 288
 289 static int maxkqevents;
 290 static struct kevent* kqevents;
 291 static int nkqevents;
 292 static struct kevent* kqrevents;
 293 static int* kqrfdidx;
 294 static int kq;
 295
 296
 297 static int
 298 kqueue_init( int nf )
 299     {
 300     kq = kqueue();
 301     if ( kq == -1 )
 302         return -1;
 303     maxkqevents = nf * 2;
 304     kqevents = (struct kevent*) malloc( sizeof(struct kevent) * maxkqevents );
 305     kqrevents = (struct kevent*) malloc( sizeof(struct kevent) * nf );
 306     kqrfdidx = (int*) malloc( sizeof(int) * nf );
 307     if ( kqevents == (struct kevent*) 0 || kqrevents == (struct kevent*) 0 ||
 308          kqrfdidx == (int*) 0 )
 309         return -1;
 310     (void) memset( kqevents, 0, sizeof(struct kevent) * maxkqevents );
 311     (void) memset( kqrfdidx, 0, sizeof(int) * nf );
 312     return 0;
 313     }
 314
 315
 316 static void
 317 kqueue_add_fd( int fd, int rw )
 318     {
 319     if ( nkqevents >= maxkqevents )
 320         {
 321         syslog( LOG_ERR, "too many kqevents in kqueue_add_fd!" );
 322         return;
 323         }
 324     kqevents[nkqevents].ident = fd;
 325     kqevents[nkqevents].flags = EV_ADD;
 326     switch ( rw )
 327         {
 328         case FDW_READ: kqevents[nkqevents].filter = EVFILT_READ; break;
 329         case FDW_WRITE: kqevents[nkqevents].filter = EVFILT_WRITE; break;
 330         default: break;
 331         }
 332     ++nkqevents;
 333     }
 334
 335
 336 static void
 337 kqueue_del_fd( int fd )
 338     {
 339     if ( nkqevents >= maxkqevents )
 340         {
 341         syslog( LOG_ERR, "too many kqevents in kqueue_del_fd!" );
 342         return;
 343         }
 344     kqevents[nkqevents].ident = fd;
 345     kqevents[nkqevents].flags = EV_DELETE;
 346     switch ( fd_rw[fd] )
 347         {
 348         case FDW_READ: kqevents[nkqevents].filter = EVFILT_READ; break;
 349         case FDW_WRITE: kqevents[nkqevents].filter = EVFILT_WRITE; break;
 350         }
 351     ++nkqevents;
 352     }
 353
 354
 355 static int
 356 kqueue_watch( long timeout_msecs )
 357     {
 358     int i, r;
 359
 360     if ( timeout_msecs == INFTIM )
 361         r = kevent(
 362             kq, kqevents, nkqevents, kqrevents, nfiles, (struct timespec*) 0 );
 363     else
 364         {
 365         struct timespec ts;
 366         ts.tv_sec = timeout_msecs / 1000L;
 367         ts.tv_nsec = ( timeout_msecs % 1000L ) * 1000000L;
 368         r = kevent( kq, kqevents, nkqevents, kqrevents, nfiles, &ts );
 369         }
 370     nkqevents = 0;
 371     if ( r == -1 )
 372         return -1;
 373
 374     for ( i = 0; i < r; ++i )
 375         kqrfdidx[kqrevents[i].ident] = i;
 376
 377     return r;
 378     }
 379
 380
 381 static int
 382 kqueue_check_fd( int fd )
 383     {
 384     int ridx = kqrfdidx[fd];
 385
 386     if ( ridx < 0 || ridx >= nfiles )
 387         {
 388         syslog( LOG_ERR, "bad ridx (%d) in kqueue_check_fd!", ridx );
 389         return 0;
 390         }
 391     if ( ridx >= nreturned )
 392         return 0;
 393     if ( kqrevents[ridx].ident != fd )
 394         return 0;
 395     if ( kqrevents[ridx].flags & EV_ERROR )
 396         return 0;
 397     switch ( fd_rw[fd] )
 398         {
 399         case FDW_READ: return kqrevents[ridx].filter == EVFILT_READ;
 400         case FDW_WRITE: return kqrevents[ridx].filter == EVFILT_WRITE;
 401         default: return 0;
 402         }
 403     }
 404
 405
 406 static int
 407 kqueue_get_fd( int ridx )
 408     {
 409     if ( ridx < 0 || ridx >= nfiles )
 410         {
 411         syslog( LOG_ERR, "bad ridx (%d) in kqueue_get_fd!", ridx );
 412         return -1;
 413         }
 414     return kqrevents[ridx].ident;
 415     }
 416
 417 #else /* HAVE_KQUEUE */
 418
 419
 420 # ifdef HAVE_DEVPOLL
 421
 422 static int maxdpevents;
 423 static struct pollfd* dpevents;
 424 static int ndpevents;
 425 static struct pollfd* dprevents;
 426 static int* dp_rfdidx;
 427 static int dp;
 428
 429
 430 static int
 431 devpoll_init( int nf )
 432     {
 433     dp = open( "/dev/poll", O_RDWR );
 434     if ( dp == -1 )
 435         return -1;
 436     (void) fcntl( dp, F_SETFD, 1 );
 437     maxdpevents = nf * 2;
 438     dpevents = (struct pollfd*) malloc( sizeof(struct pollfd) * maxdpevents );
 439     dprevents = (struct pollfd*) malloc( sizeof(struct pollfd) * nf );
 440     dp_rfdidx = (int*) malloc( sizeof(int) * nf );
 441     if ( dpevents == (struct pollfd*) 0 || dprevents == (struct pollfd*) 0 ||
 442          dp_rfdidx == (int*) 0 )
 443         return -1;
 444     (void) memset( dp_rfdidx, 0, sizeof(int) * nf );
 445     return 0;
 446     }
 447
 448
 449 static void
 450 devpoll_add_fd( int fd, int rw )
 451     {
 452     if ( ndpevents >= maxdpevents )
 453         {
 454         syslog( LOG_ERR, "too many fds in devpoll_add_fd!" );
 455         return;
 456         }
 457     dpevents[ndpevents].fd = fd;
 458     switch ( rw )
 459         {
 460         case FDW_READ: dpevents[ndpevents].events = POLLIN; break;
 461         case FDW_WRITE: dpevents[ndpevents].events = POLLOUT; break;
 462         default: break;
 463         }
 464     ++ndpevents;
 465     }
 466
 467
 468 static void
 469 devpoll_del_fd( int fd )
 470     {
 471     if ( ndpevents >= maxdpevents )
 472         {
 473         syslog( LOG_ERR, "too many fds in devpoll_del_fd!" );
 474         return;
 475         }
 476     dpevents[ndpevents].fd = fd;
 477     dpevents[ndpevents].events = POLLREMOVE;
 478     ++ndpevents;
 479     }
 480
 481
 482 static int
 483 devpoll_watch( long timeout_msecs )
 484     {
 485     int i, r;
 486     struct dvpoll dvp;
 487
 488     r = sizeof(struct pollfd) * ndpevents;
 489     if ( r > 0 && write( dp, dpevents, r ) != r )
 490         return -1;
 491
 492     ndpevents = 0;
 493     dvp.dp_fds = dprevents;
 494     dvp.dp_nfds = nfiles;
 495     dvp.dp_timeout = (int) timeout_msecs;
 496
 497     r = ioctl( dp, DP_POLL, &dvp );
 498     if ( r == -1 )
 499         return -1;
 500
 501     for ( i = 0; i < r; ++i )
 502         dp_rfdidx[dprevents[i].fd] = i;
 503
 504     return r;
 505     }
 506
 507
 508 static int
 509 devpoll_check_fd( int fd )
 510     {
 511     int ridx = dp_rfdidx[fd];
 512
 513     if ( ridx < 0 || ridx >= nfiles )
 514         {
 515         syslog( LOG_ERR, "bad ridx (%d) in devpoll_check_fd!", ridx );
 516         return 0;
 517         }
 518     if ( ridx >= nreturned )
 519         return 0;
 520     if ( dprevents[ridx].fd != fd )
 521         return 0;
 522     if ( dprevents[ridx].revents & POLLERR )
 523         return 0;
 524     switch ( fd_rw[fd] )
 525         {
 526         case FDW_READ: return dprevents[ridx].revents & ( POLLIN | POLLHUP | POLLNVAL );
 527         case FDW_WRITE: return dprevents[ridx].revents & ( POLLOUT | POLLHUP | POLLNVAL );
 528         default: return 0;
 529         }
 530     }
 531
 532
 533 static int
 534 devpoll_get_fd( int ridx )
 535     {
 536     if ( ridx < 0 || ridx >= nfiles )
 537         {
 538         syslog( LOG_ERR, "bad ridx (%d) in devpoll_get_fd!", ridx );
 539         return -1;
 540         }
 541     return dprevents[ridx].fd;
 542     }
 543
 544
 545 # else /* HAVE_DEVPOLL */
 546
 547
 548 #  ifdef HAVE_POLL
 549
 550 static struct pollfd* pollfds;
 551 static int npoll_fds;
 552 static int* poll_fdidx;
 553 static int* poll_rfdidx;
 554
 555
 556 static int
 557 poll_init( int nf )
 558     {
 559     int i;
 560
 561     pollfds = (struct pollfd*) malloc( sizeof(struct pollfd) * nf );
 562     poll_fdidx = (int*) malloc( sizeof(int) * nf );
 563     poll_rfdidx = (int*) malloc( sizeof(int) * nf );
 564     if ( pollfds == (struct pollfd*) 0 || poll_fdidx == (int*) 0 ||
 565          poll_rfdidx == (int*) 0 )
 566         return -1;
 567     for ( i = 0; i < nf; ++i )
 568         pollfds[i].fd = poll_fdidx[i] = -1;
 569     return 0;
 570     }
 571
 572
 573 static void
 574 poll_add_fd( int fd, int rw )
 575     {
 576     if ( npoll_fds >= nfiles )
 577         {
 578         syslog( LOG_ERR, "too many fds in poll_add_fd!" );
 579         return;
 580         }
 581     pollfds[npoll_fds].fd = fd;
 582     switch ( rw )
 583         {
 584         case FDW_READ: pollfds[npoll_fds].events = POLLIN; break;
 585         case FDW_WRITE: pollfds[npoll_fds].events = POLLOUT; break;
 586         default: break;
 587         }
 588     poll_fdidx[fd] = npoll_fds;
 589     ++npoll_fds;
 590     }
 591
 592
 593 static void
 594 poll_del_fd( int fd )
 595     {
 596     int idx = poll_fdidx[fd];
 597
 598     if ( idx < 0 || idx >= nfiles )
 599         {
 600         syslog( LOG_ERR, "bad idx (%d) in poll_del_fd!", idx );
 601         return;
 602         }
 603     --npoll_fds;
 604     pollfds[idx] = pollfds[npoll_fds];
 605     poll_fdidx[pollfds[idx].fd] = idx;
 606     pollfds[npoll_fds].fd = -1;
 607     poll_fdidx[fd] = -1;
 608     }
 609
 610
 611 static int
 612 poll_watch( long timeout_msecs )
 613     {
 614     int r, ridx, i;
 615
 616     r = poll( pollfds, npoll_fds, (int) timeout_msecs );
 617     if ( r <= 0 )
 618         return r;
 619
 620     ridx = 0;
 621     for ( i = 0; i < npoll_fds; ++i )
 622         if ( pollfds[i].revents &
 623              ( POLLIN | POLLOUT | POLLERR | POLLHUP | POLLNVAL ) )
 624             {
 625             poll_rfdidx[ridx++] = pollfds[i].fd;
 626             if ( ridx == r )
 627                 break;
 628             }
 629
 630     return ridx;        /* should be equal to r */
 631     }
 632
 633
 634 static int
 635 poll_check_fd( int fd )
 636     {
 637     int fdidx = poll_fdidx[fd];
 638
 639     if ( fdidx < 0 || fdidx >= nfiles )
 640         {
 641         syslog( LOG_ERR, "bad fdidx (%d) in poll_check_fd!", fdidx );
 642         return 0;
 643         }
 644     if ( pollfds[fdidx].revents & POLLERR )
 645         return 0;
 646     switch ( fd_rw[fd] )
 647         {
 648         case FDW_READ: return pollfds[fdidx].revents & ( POLLIN | POLLHUP | POLLNVAL );
 649         case FDW_WRITE: return pollfds[fdidx].revents & ( POLLOUT | POLLHUP | POLLNVAL );
 650         default: return 0;
 651         }
 652     }
 653
 654
 655 static int
 656 poll_get_fd( int ridx )
 657     {
 658     if ( ridx < 0 || ridx >= nfiles )
 659         {
 660         syslog( LOG_ERR, "bad ridx (%d) in poll_get_fd!", ridx );
 661         return -1;
 662         }
 663     return poll_rfdidx[ridx];
 664     }
 665
 666 #  else /* HAVE_POLL */
 667
 668
 669 #   ifdef HAVE_SELECT
 670
 671 static fd_set master_rfdset;
 672 static fd_set master_wfdset;
 673 static fd_set working_rfdset;
 674 static fd_set working_wfdset;
 675 static int* select_fds;
 676 static int* select_fdidx;
 677 static int* select_rfdidx;
 678 static int nselect_fds;
 679 static int maxfd;
 680 static int maxfd_changed;
 681
 682
 683 static int
 684 select_init( int nf )
 685     {
 686     int i;
 687
 688     FD_ZERO( &master_rfdset );
 689     FD_ZERO( &master_wfdset );
 690     select_fds = (int*) malloc( sizeof(int) * nf );
 691     select_fdidx = (int*) malloc( sizeof(int) * nf );
 692     select_rfdidx = (int*) malloc( sizeof(int) * nf );
 693     if ( select_fds == (int*) 0 || select_fdidx == (int*) 0 ||
 694          select_rfdidx == (int*) 0 )
 695         return -1;
 696     nselect_fds = 0;
 697     maxfd = -1;
 698     maxfd_changed = 0;
 699     for ( i = 0; i < nf; ++i )
 700         select_fds[i] = select_fdidx[i] = -1;
 701     return 0;
 702     }
 703
 704
 705 static void
 706 select_add_fd( int fd, int rw )
 707     {
 708     if ( nselect_fds >= nfiles )
 709         {
 710         syslog( LOG_ERR, "too many fds in select_add_fd!" );
 711         return;
 712         }
 713     select_fds[nselect_fds] = fd;
 714     switch ( rw )
 715         {
 716         case FDW_READ: FD_SET( fd, &master_rfdset ); break;
 717         case FDW_WRITE: FD_SET( fd, &master_wfdset ); break;
 718         default: break;
 719         }
 720     if ( fd > maxfd )
 721         maxfd = fd;
 722     select_fdidx[fd] = nselect_fds;
 723     ++nselect_fds;
 724     }
 725
 726
 727 static void
 728 select_del_fd( int fd )
 729     {
 730     int idx = select_fdidx[fd];
 731
 732     if ( idx < 0 || idx >= nfiles )
 733         {
 734         syslog( LOG_ERR, "bad idx (%d) in select_del_fd!", idx );
 735         return;
 736         }
 737
 738     --nselect_fds;
 739     select_fds[idx] = select_fds[nselect_fds];
 740     select_fdidx[select_fds[idx]] = idx;
 741     select_fds[nselect_fds] = -1;
 742     select_fdidx[fd] = -1;
 743
 744     FD_CLR( fd, &master_rfdset );
 745     FD_CLR( fd, &master_wfdset );
 746
 747     if ( fd >= maxfd )
 748         maxfd_changed = 1;
 749     }
 750
 751
 752 static int
 753 select_get_maxfd( void )
 754     {
 755     if ( maxfd_changed )
 756         {
 757         int i;
 758         maxfd = -1;
 759         for ( i = 0; i < nselect_fds; ++i )
 760             if ( select_fds[i] > maxfd )
 761                 maxfd = select_fds[i];
 762         maxfd_changed = 0;
 763         }
 764     return maxfd;
 765     }
 766
 767
 768 static int
 769 select_watch( long timeout_msecs )
 770     {
 771     int mfd;
 772     int r, idx, ridx;
 773
 774     working_rfdset = master_rfdset;
 775     working_wfdset = master_wfdset;
 776     mfd = select_get_maxfd();
 777     if ( timeout_msecs == INFTIM )
 778        r = select(
 779            mfd + 1, &working_rfdset, &working_wfdset, (fd_set*) 0,
 780            (struct timeval*) 0 );
 781     else
 782         {
 783         struct timeval timeout;
 784         timeout.tv_sec = timeout_msecs / 1000L;
 785         timeout.tv_usec = ( timeout_msecs % 1000L ) * 1000L;
 786         r = select(
 787            mfd + 1, &working_rfdset, &working_wfdset, (fd_set*) 0, &timeout );
 788         }
 789     if ( r <= 0 )
 790         return r;
 791
 792     ridx = 0;
 793     for ( idx = 0; idx < nselect_fds; ++idx )
 794         if ( select_check_fd( select_fds[idx] ) )
 795             {
 796             select_rfdidx[ridx++] = select_fds[idx];
 797             if ( ridx == r )
 798                 break;
 799             }
 800
 801     return ridx;        /* should be equal to r */
 802     }
 803
 804
 805 static int
 806 select_check_fd( int fd )
 807     {
 808     switch ( fd_rw[fd] )
 809         {
 810         case FDW_READ: return FD_ISSET( fd, &working_rfdset );
 811         case FDW_WRITE: return FD_ISSET( fd, &working_wfdset );
 812         default: return 0;
 813         }
 814     }
 815
 816
 817 static int
 818 select_get_fd( int ridx )
 819     {
 820     if ( ridx < 0 || ridx >= nfiles )
 821         {
 822         syslog( LOG_ERR, "bad ridx (%d) in select_get_fd!", ridx );
 823         return -1;
 824         }
 825     return select_rfdidx[ridx];
 826     }
 827
 828 #   endif /* HAVE_SELECT */
 829
 830 #  endif /* HAVE_POLL */
 831
 832 # endif /* HAVE_DEVPOLL */
 833
 834 #endif /* HAVE_KQUEUE */