scheduler/select.c

   1 /*
   2  * "$Id: select.c 7093 2007-11-30 19:09:36Z mike $"
   3  *
   4  *   Select abstraction functions for the Common UNIX Printing System (CUPS).
   5  *
   6  *   Copyright 2007 by Apple Inc.
   7  *   Copyright 2006-2007 by Easy Software Products.
   8  *
   9  *   These coded instructions, statements, and computer programs are the
  10  *   property of Apple Inc. and are protected by Federal copyright
  11  *   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
  12  *   which should have been included with this file.  If this file is
  13  *   file is missing or damaged, see the license at "http://www.cups.org/".
  14  *
  15  * Contents:
  16  *
  17  *   cupsdAddSelect()    - Add a file descriptor to the list.
  18  *   cupsdDoSelect()     - Do a select-like operation.
  19  *   cupsdIsSelecting()  - Determine whether we are monitoring a file
  20  *                         descriptor.
  21  *   cupsdRemoveSelect() - Remove a file descriptor from the list.
  22  *   cupsdStartSelect()  - Initialize the file polling engine.
  23  *   cupsdStopSelect()   - Shutdown the file polling engine.
  24  *   compare_fds()       - Compare file descriptors.
  25  *   find_fd()           - Find an existing file descriptor record.
  26  */
  27
  28 /*
  29  * Include necessary headers...
  30  */
  31
  32 #include "cupsd.h"
  33
  34 #ifdef HAVE_EPOLL
  35 #  include <sys/epoll.h>
  36 #  include <sys/poll.h>
  37 #elif defined(HAVE_KQUEUE)
  38 #  include <sys/event.h>
  39 #  include <sys/time.h>
  40 #elif defined(HAVE_POLL)
  41 #  include <sys/poll.h>
  42 #elif defined(__hpux)
  43 #  include <sys/time.h>
  44 #else
  45 #  include <sys/select.h>
  46 #endif /* HAVE_EPOLL */
  47
  48
  49 /*
  50  * Design Notes for Poll/Select API in CUPSD
  51  * -----------------------------------------
  52  *
  53  * SUPPORTED APIS
  54  *
  55  *     OS              select  poll    epoll   kqueue  /dev/poll
  56  *     --------------  ------  ------  ------  ------  ---------
  57  *     AIX             YES     YES     NO      NO      NO
  58  *     FreeBSD         YES     YES     NO      YES     NO
  59  *     HP-UX           YES     YES     NO      NO      NO
  60  *     IRIX            YES     YES     NO      NO      NO
  61  *     Linux           YES     YES     YES     NO      NO
  62  *     MacOS X         YES     YES     NO      YES     NO
  63  *     NetBSD          YES     YES     NO      YES     NO
  64  *     OpenBSD         YES     YES     NO      YES     NO
  65  *     Solaris         YES     YES     NO      NO      YES
  66  *     Tru64           YES     YES     NO      NO      NO
  67  *     Windows         YES     NO      NO      NO      NO
  68  *
  69  *
  70  * HIGH-LEVEL API
  71  *
  72  *     typedef void (*cupsd_selfunc_t)(void *data);
  73  *
  74  *     void cupsdStartSelect(void);
  75  *     void cupsdStopSelect(void);
  76  *     void cupsdAddSelect(int fd, cupsd_selfunc_t read_cb,
  77  *                         cupsd_selfunc_t write_cb, void *data);
  78  *     void cupsdRemoveSelect(int fd);
  79  *     int cupsdDoSelect(int timeout);
  80  *
  81  *
  82  * IMPLEMENTATION STRATEGY
  83  *
  84  *     0. Common Stuff
  85  *         a. CUPS array of file descriptor to callback functions
  86  *            and data + temporary array of removed fd's.
  87  *         b. cupsdStartSelect() creates the arrays
  88  *         c. cupsdStopSelect() destroys the arrays and all elements.
  89  *         d. cupsdAddSelect() adds to the array and allocates a
  90  *            new callback element.
  91  *         e. cupsdRemoveSelect() removes from the active array and
  92  *            adds to the inactive array.
  93  *         f. _cupsd_fd_t provides a reference-counted structure for
  94  *            tracking file descriptors that are monitored.
  95  *         g. cupsdDoSelect() frees all inactive FDs.
  96  *
  97  *     1. select() O(n)
  98  *         a. Input/Output fd_set variables, copied to working
  99  *            copies and then used with select().
 100  *         b. Loop through CUPS array, using FD_ISSET and calling
 101  *            the read/write callbacks as needed.
 102  *         c. cupsdRemoveSelect() clears fd_set bit from main and
 103  *            working sets.
 104  *         d. cupsdStopSelect() frees all of the memory used by the
 105  *            CUPS array and fd_set's.
 106  *
 107  *     2. poll() - O(n log n)
 108  *         a. Regular array of pollfd, sorted the same as the CUPS
 109  *            array.
 110  *         b. Loop through pollfd array, call the corresponding
 111  *            read/write callbacks as needed.
 112  *         c. cupsdAddSelect() adds first to CUPS array and flags the
 113  *            pollfd array as invalid.
 114  *         d. cupsdDoSelect() rebuilds pollfd array as needed, calls
 115  *            poll(), then loops through the pollfd array looking up
 116  *            as needed.
 117  *         e. cupsdRemoveSelect() flags the pollfd array as invalid.
 118  *         f. cupsdStopSelect() frees all of the memory used by the
 119  *            CUPS array and pollfd array.
 120  *
 121  *     3. epoll() - O(n)
 122  *         a. cupsdStartSelect() creates epoll file descriptor using
 123  *            epoll_create() with the maximum fd count, and
 124  *            allocates an events buffer for the maximum fd count.
 125  *         b. cupsdAdd/RemoveSelect() uses epoll_ctl() to add
 126  *            (EPOLL_CTL_ADD) or remove (EPOLL_CTL_DEL) a single
 127  *            event using the level-triggered semantics. The event
 128  *            user data field is a pointer to the new callback array
 129  *            element.
 130  *         c. cupsdDoSelect() uses epoll_wait() with the global event
 131  *            buffer allocated in cupsdStartSelect() and then loops
 132  *            through the events, using the user data field to find
 133  *            the callback record.
 134  *         d. cupsdStopSelect() closes the epoll file descriptor and
 135  *            frees all of the memory used by the event buffer.
 136  *
 137  *     4. kqueue() - O(n)
 138  *         b. cupsdStartSelect() creates kqueue file descriptor
 139  *            using kqyeue() function and allocates a global event
 140  *            buffer.
 141  *         c. cupsdAdd/RemoveSelect() uses EV_SET and kevent() to
 142  *            register the changes. The event user data field is a
 143  *            pointer to the new callback array element.
 144  *         d. cupsdDoSelect() uses kevent() to poll for events and
 145  *            loops through the events, using the user data field to
 146  *            find the callback record.
 147  *         e. cupsdStopSelect() closes the kqyeye() file descriptor
 148  *            and frees all of the memory used by the event buffer.
 149  *
 150  *     5. /dev/poll - O(n log n) - NOT YET IMPLEMENTED
 151  *         a. cupsdStartSelect() opens /dev/poll and allocates an
 152  *            array of pollfd structs; on failure to open /dev/poll,
 153  *            revert to poll() system call.
 154  *         b. cupsdAddSelect() writes a single pollfd struct to
 155  *            /dev/poll with the new file descriptor and the
 156  *            POLLIN/POLLOUT flags.
 157  *         c. cupsdRemoveSelect() writes a single pollfd struct to
 158  *            /dev/poll with the file descriptor and the POLLREMOVE
 159  *            flag.
 160  *         d. cupsdDoSelect() uses the DP_POLL ioctl to retrieve
 161  *            events from /dev/poll and then loops through the
 162  *            returned pollfd array, looking up the file descriptors
 163  *            as needed.
 164  *         e. cupsdStopSelect() closes /dev/poll and frees the
 165  *            pollfd array.
 166  *
 167  * PERFORMANCE
 168  *
 169  *   In tests using the "make test" target with option 0 (keep cupsd
 170  *   running) and the "testspeed" program with "-c 50 -r 1000", epoll()
 171  *   performed 5.5% slower than select(), followed by kqueue() at 16%
 172  *   slower than select() and poll() at 18% slower than select().  Similar
 173  *   results were seen with twice the number of client connections.
 174  *
 175  *   The epoll() and kqueue() performance is likely limited by the
 176  *   number of system calls used to add/modify/remove file
 177  *   descriptors dynamically.  Further optimizations may be possible
 178  *   in the area of limiting use of cupsdAddSelect() and
 179  *   cupsdRemoveSelect(), however extreme care will be needed to avoid
 180  *   excess CPU usage and deadlock conditions.
 181  *
 182  *   We may be able to improve the poll() implementation simply by
 183  *   keeping the pollfd array sync'd with the _cupsd_fd_t array, as that
 184  *   will eliminate the rebuilding of the array whenever there is a
 185  *   change and eliminate the fd array lookups in the inner loop of
 186  *   cupsdDoSelect().
 187  *
 188  *   Since /dev/poll will never be able to use a shadow array, it may
 189  *   not make sense to implement support for it.  ioctl() overhead will
 190  *   impact performance as well, so my guess would be that, for CUPS,
 191  *   /dev/poll will yield a net performance loss.
 192  */
 193
 194 /*
 195  * Local structures...
 196  */
 197
 198 typedef struct _cupsd_fd_s
 199 {
 200   int                   fd,             /* File descriptor */
 201                         use;            /* Use count */
 202   cupsd_selfunc_t       read_cb,        /* Read callback */
 203                         write_cb;       /* Write callback */
 204   void                  *data;          /* Data pointer for callbacks */
 205 } _cupsd_fd_t;
 206
 207
 208 /*
 209  * Local globals...
 210  */
 211
 212 static cups_array_t     *cupsd_fds = NULL;
 213 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 214 static cups_array_t     *cupsd_inactive_fds = NULL;
 215 static int              cupsd_in_select = 0;
 216 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 217
 218 #ifdef HAVE_KQUEUE
 219 static int              cupsd_kqueue_fd = -1,
 220                         cupsd_kqueue_changes = 0;
 221 static struct kevent    *cupsd_kqueue_events = NULL;
 222 #elif defined(HAVE_POLL)
 223 static int              cupsd_alloc_pollfds = 0,
 224                         cupsd_update_pollfds = 0;
 225 static struct pollfd    *cupsd_pollfds = NULL;
 226 #  ifdef HAVE_EPOLL
 227 static int              cupsd_epoll_fd = -1;
 228 static struct epoll_event *cupsd_epoll_events = NULL;
 229 #  endif /* HAVE_EPOLL */
 230 #else /* select() */
 231 static fd_set           cupsd_global_input,
 232                         cupsd_global_output,
 233                         cupsd_current_input,
 234                         cupsd_current_output;
 235 #endif /* HAVE_KQUEUE */
 236
 237
 238 /*
 239  * Local functions...
 240  */
 241
 242 static int              compare_fds(_cupsd_fd_t *a, _cupsd_fd_t *b);
 243 static _cupsd_fd_t      *find_fd(int fd);
 244 #define                 release_fd(f) { \
 245                           (f)->use --; \
 246                           if (!(f)->use) free((f));\
 247                         }
 248 #define                 retain_fd(f) (f)->use++
 249
 250
 251 /*
 252  * 'cupsdAddSelect()' - Add a file descriptor to the list.
 253  */
 254
 255 int                                     /* O - 1 on success, 0 on error */
 256 cupsdAddSelect(int             fd,      /* I - File descriptor */
 257                cupsd_selfunc_t read_cb, /* I - Read callback */
 258                cupsd_selfunc_t write_cb,/* I - Write callback */
 259                void            *data)   /* I - Data to pass to callback */
 260 {
 261   _cupsd_fd_t   *fdptr;                 /* File descriptor record */
 262   int           added;                  /* 1 if added, 0 if modified */
 263
 264
 265  /*
 266   * Range check input...
 267   */
 268
 269   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 270                   "cupsdAddSelect: fd=%d, read_cb=%p, write_cb=%p, data=%p",
 271                   fd, read_cb, write_cb, data);
 272
 273   if (fd < 0)
 274     return (0);
 275
 276  /*
 277   * See if this FD has already been added...
 278   */
 279
 280   if ((fdptr = find_fd(fd)) == NULL)
 281   {
 282    /*
 283     * No, add a new entry...
 284     */
 285
 286     if ((fdptr = calloc(1, sizeof(_cupsd_fd_t))) == NULL)
 287       return (0);
 288
 289     fdptr->fd  = fd;
 290     fdptr->use = 1;
 291
 292     if (!cupsArrayAdd(cupsd_fds, fdptr))
 293     {
 294       cupsdLogMessage(CUPSD_LOG_EMERG, "Unable to add fd %d to array!", fd);
 295       free(fdptr);
 296       return (0);
 297     }
 298
 299     added = 1;
 300   }
 301   else
 302     added = 0;
 303
 304 #ifdef HAVE_KQUEUE
 305   {
 306     struct kevent       event;          /* Event data */
 307     struct timespec     timeout;        /* Timeout value */
 308
 309
 310     timeout.tv_sec  = 0;
 311     timeout.tv_nsec = 0;
 312
 313     if (fdptr->read_cb != read_cb)
 314     {
 315       if (read_cb)
 316         EV_SET(&event, fd, EVFILT_READ, EV_ADD, 0, 0, fdptr);
 317       else
 318         EV_SET(&event, fd, EVFILT_READ, EV_DELETE, 0, 0, fdptr);
 319
 320       if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 321       {
 322         cupsdLogMessage(CUPSD_LOG_DEBUG2,
 323                         "cupsdAddSelect: kevent() returned %s",
 324                         strerror(errno));
 325         return (0);
 326       }
 327     }
 328
 329     if (fdptr->write_cb != write_cb)
 330     {
 331       if (write_cb)
 332         EV_SET(&event, fd, EVFILT_WRITE, EV_ADD, 0, 0, fdptr);
 333       else
 334         EV_SET(&event, fd, EVFILT_WRITE, EV_DELETE, 0, 0, fdptr);
 335
 336       if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 337       {
 338         cupsdLogMessage(CUPSD_LOG_DEBUG2,
 339                         "cupsdAddSelect: kevent() returned %s",
 340                         strerror(errno));
 341         return (0);
 342       }
 343     }
 344   }
 345
 346 #elif defined(HAVE_POLL)
 347 #  ifdef HAVE_EPOLL
 348   if (cupsd_epoll_fd >= 0)
 349   {
 350     struct epoll_event event;           /* Event data */
 351
 352
 353     event.events = 0;
 354
 355     if (read_cb)
 356       event.events |= EPOLLIN;
 357
 358     if (write_cb)
 359       event.events |= EPOLLOUT;
 360
 361     event.data.ptr = fdptr;
 362
 363     if (epoll_ctl(cupsd_epoll_fd, added ? EPOLL_CTL_ADD : EPOLL_CTL_MOD, fd,
 364                   &event))
 365     {
 366       close(cupsd_epoll_fd);
 367       cupsd_epoll_fd       = -1;
 368       cupsd_update_pollfds = 1;
 369     }
 370   }
 371   else
 372 #  endif /* HAVE_EPOLL */
 373
 374   cupsd_update_pollfds = 1;
 375
 376 #else /* select() */
 377  /*
 378   * Add or remove the file descriptor in the input and output sets
 379   * for select()...
 380   */
 381
 382   if (read_cb)
 383   {
 384     cupsdLogMessage(CUPSD_LOG_DEBUG2,
 385                     "cupsdAddSelect: Adding fd %d to input set...", fd);
 386     FD_SET(fd, &cupsd_global_input);
 387   }
 388   else
 389   {
 390     cupsdLogMessage(CUPSD_LOG_DEBUG2,
 391                     "cupsdAddSelect: Removing fd %d from input set...", fd);
 392     FD_CLR(fd, &cupsd_global_input);
 393     FD_CLR(fd, &cupsd_current_input);
 394   }
 395
 396   if (write_cb)
 397   {
 398     cupsdLogMessage(CUPSD_LOG_DEBUG2,
 399                     "cupsdAddSelect: Adding fd %d to output set...", fd);
 400     FD_SET(fd, &cupsd_global_output);
 401   }
 402   else
 403   {
 404     cupsdLogMessage(CUPSD_LOG_DEBUG2,
 405                     "cupsdAddSelect: Removing fd %d from output set...", fd);
 406     FD_CLR(fd, &cupsd_global_output);
 407     FD_CLR(fd, &cupsd_current_output);
 408   }
 409 #endif /* HAVE_KQUEUE */
 410
 411  /*
 412   * Save the (new) read and write callbacks...
 413   */
 414
 415   fdptr->read_cb  = read_cb;
 416   fdptr->write_cb = write_cb;
 417   fdptr->data     = data;
 418
 419   return (1);
 420 }
 421
 422
 423 /*
 424  * 'cupsdDoSelect()' - Do a select-like operation.
 425  */
 426
 427 int                                     /* O - Number of files or -1 on error */
 428 cupsdDoSelect(long timeout)             /* I - Timeout in seconds */
 429 {
 430   int                   nfds;           /* Number of file descriptors */
 431   _cupsd_fd_t           *fdptr;         /* Current file descriptor */
 432 #ifdef HAVE_KQUEUE
 433   int                   i;              /* Looping var */
 434   struct kevent         *event;         /* Current event */
 435   struct timespec       ktimeout;       /* kevent() timeout */
 436
 437
 438   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 439                   "cupsdDoSelect: polling %d fds for %ld seconds...",
 440                   cupsArrayCount(cupsd_fds), timeout);
 441
 442   cupsd_in_select = 1;
 443
 444   if (timeout >= 0 && timeout < 86400)
 445   {
 446     ktimeout.tv_sec  = timeout;
 447     ktimeout.tv_nsec = 0;
 448
 449     nfds = kevent(cupsd_kqueue_fd, NULL, 0, cupsd_kqueue_events, MaxFDs,
 450                   &ktimeout);
 451   }
 452   else
 453     nfds = kevent(cupsd_kqueue_fd, NULL, 0, cupsd_kqueue_events, MaxFDs, NULL);
 454
 455   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 456                   "cupsdDoSelect: kevent(%d, ..., %d, ...) returned %d...",
 457                   cupsd_kqueue_fd, MaxFDs, nfds);
 458
 459   cupsd_kqueue_changes = 0;
 460
 461   for (i = nfds, event = cupsd_kqueue_events; i > 0; i --, event ++)
 462   {
 463     fdptr = (_cupsd_fd_t *)event->udata;
 464
 465     if (cupsArrayFind(cupsd_inactive_fds, fdptr))
 466       continue;
 467
 468     cupsdLogMessage(CUPSD_LOG_DEBUG2, "event->filter=%d, event->ident=%d",
 469                     event->filter, (int)event->ident);
 470
 471     retain_fd(fdptr);
 472
 473     if (fdptr->read_cb && event->filter == EVFILT_READ)
 474     {
 475       cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Read on fd %d...",
 476                       fdptr->fd);
 477       (*(fdptr->read_cb))(fdptr->data);
 478     }
 479
 480     if (fdptr->write_cb && event->filter == EVFILT_WRITE)
 481     {
 482       cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Write on fd %d...",
 483                       fdptr->fd);
 484       (*(fdptr->write_cb))(fdptr->data);
 485     }
 486
 487     release_fd(fdptr);
 488   }
 489
 490 #elif defined(HAVE_POLL)
 491   struct pollfd         *pfd;           /* Current pollfd structure */
 492   int                   count;          /* Number of file descriptors */
 493
 494
 495   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 496                   "cupsdDoSelect: polling %d fds for %ld seconds...",
 497                   cupsArrayCount(cupsd_fds), timeout);
 498
 499 #  ifdef HAVE_EPOLL
 500   cupsd_in_select = 1;
 501
 502   if (cupsd_epoll_fd >= 0)
 503   {
 504     int                 i;              /* Looping var */
 505     struct epoll_event  *event;         /* Current event */
 506
 507
 508     if (timeout >= 0 && timeout < 86400)
 509       nfds = epoll_wait(cupsd_epoll_fd, cupsd_epoll_events, MaxFDs,
 510                         timeout * 1000);
 511     else
 512       nfds = epoll_wait(cupsd_epoll_fd, cupsd_epoll_events, MaxFDs, -1);
 513
 514     cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: epoll() returned %d...",
 515                     nfds);
 516
 517     if (nfds < 0 && errno != EINTR)
 518     {
 519       close(cupsd_epoll_fd);
 520       cupsd_epoll_fd = -1;
 521     }
 522     else
 523     {
 524       for (i = nfds, event = cupsd_epoll_events; i > 0; i --, event ++)
 525       {
 526         fdptr = (_cupsd_fd_t *)event->data.ptr;
 527
 528         if (cupsArrayFind(cupsd_inactive_fds, fdptr))
 529           continue;
 530
 531         retain_fd(fdptr);
 532
 533         if (fdptr->read_cb && (event->events & (EPOLLIN | EPOLLERR | EPOLLHUP)))
 534         {
 535           cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Read on fd %d...",
 536                           fdptr->fd);
 537           (*(fdptr->read_cb))(fdptr->data);
 538         }
 539
 540         if (fdptr->write_cb && (event->events & (EPOLLOUT | EPOLLERR | EPOLLHUP)))
 541         {
 542           cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Write on fd %d...",
 543                           fdptr->fd);
 544           (*(fdptr->write_cb))(fdptr->data);
 545         }
 546
 547         release_fd(fdptr);
 548       }
 549
 550       goto release_inactive;
 551     }
 552   }
 553 #  endif /* HAVE_EPOLL */
 554
 555   count = cupsArrayCount(cupsd_fds);
 556
 557   if (cupsd_update_pollfds)
 558   {
 559    /*
 560     * Update the cupsd_pollfds array to match the current FD array...
 561     */
 562
 563     cupsd_update_pollfds = 0;
 564
 565     cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Updating pollfd array...");
 566
 567    /*
 568     * (Re)allocate memory as needed...
 569     */
 570
 571     if (count > cupsd_alloc_pollfds)
 572     {
 573       int allocfds = count + 16;
 574
 575
 576       if (cupsd_pollfds)
 577         pfd = realloc(cupsd_pollfds, allocfds * sizeof(struct pollfd));
 578       else
 579         pfd = malloc(allocfds * sizeof(struct pollfd));
 580
 581       if (!pfd)
 582       {
 583         cupsdLogMessage(CUPSD_LOG_EMERG,
 584                         "Unable to allocate %d bytes for polling!",
 585                         (int)(allocfds * sizeof(struct pollfd)));
 586
 587         return (-1);
 588       }
 589
 590       cupsd_pollfds       = pfd;
 591       cupsd_alloc_pollfds = allocfds;
 592     }
 593
 594    /*
 595     * Rebuild the array...
 596     */
 597
 598     for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds), pfd = cupsd_pollfds;
 599          fdptr;
 600          fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds), pfd ++)
 601     {
 602       pfd->fd      = fdptr->fd;
 603       pfd->events  = 0;
 604
 605       if (fdptr->read_cb)
 606         pfd->events |= POLLIN;
 607
 608       if (fdptr->write_cb)
 609         pfd->events |= POLLOUT;
 610     }
 611   }
 612
 613   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 614                   "cupsdDoSelect: polling %d fds for %ld seconds...",
 615                   count, timeout);
 616
 617   if (timeout >= 0 && timeout < 86400)
 618     nfds = poll(cupsd_pollfds, count, timeout * 1000);
 619   else
 620     nfds = poll(cupsd_pollfds, count, -1);
 621
 622   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: poll() returned %d...",
 623                   nfds);
 624
 625   if (nfds > 0)
 626   {
 627    /*
 628     * Do callbacks for each file descriptor...
 629     */
 630
 631     for (pfd = cupsd_pollfds; count > 0; pfd ++, count --)
 632     {
 633       cupsdLogMessage(CUPSD_LOG_DEBUG2,
 634                       "cupsdDoSelect: pollfds[%d]={fd=%d, revents=%x}",
 635                       pfd - cupsd_pollfds, pfd->fd, pfd->revents);
 636
 637       if (!pfd->revents)
 638         continue;
 639
 640       if ((fdptr = find_fd(pfd->fd)) == NULL)
 641         continue;
 642
 643       retain_fd(fdptr);
 644
 645       if (fdptr->read_cb && (pfd->revents & (POLLIN | POLLERR | POLLHUP)))
 646       {
 647         cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Read on fd %d...",
 648                         fdptr->fd);
 649         (*(fdptr->read_cb))(fdptr->data);
 650       }
 651
 652       if (fdptr->write_cb && (pfd->revents & (POLLOUT | POLLERR | POLLHUP)))
 653       {
 654         cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Write on fd %d...",
 655                         fdptr->fd);
 656         (*(fdptr->write_cb))(fdptr->data);
 657       }
 658
 659       release_fd(fdptr);
 660     }
 661   }
 662
 663 #else /* select() */
 664   struct timeval        stimeout;       /* Timeout for select() */
 665   int                   maxfd;          /* Maximum file descriptor */
 666
 667
 668  /*
 669   * Figure out the highest file descriptor number...
 670   */
 671
 672   if ((fdptr = (_cupsd_fd_t *)cupsArrayLast(cupsd_fds)) == NULL)
 673     maxfd = 1;
 674   else
 675     maxfd = fdptr->fd + 1;
 676
 677  /*
 678   * Do the select()...
 679   */
 680
 681   cupsd_current_input  = cupsd_global_input;
 682   cupsd_current_output = cupsd_global_output;
 683
 684   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 685                   "cupsdDoSelect: selecting %d fds for %ld seconds...",
 686                   maxfd, timeout);
 687
 688   if (timeout >= 0 && timeout < 86400)
 689   {
 690     stimeout.tv_sec  = timeout;
 691     stimeout.tv_usec = 0;
 692
 693     nfds = select(maxfd, &cupsd_current_input, &cupsd_current_output, NULL,
 694                   &stimeout);
 695   }
 696   else
 697     nfds = select(maxfd, &cupsd_current_input, &cupsd_current_output, NULL,
 698                   NULL);
 699
 700   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: select() returned %d...",
 701                   nfds);
 702
 703   if (nfds > 0)
 704   {
 705    /*
 706     * Do callbacks for each file descriptor...
 707     */
 708
 709     for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds);
 710          fdptr;
 711          fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds))
 712     {
 713       retain_fd(fdptr);
 714
 715       if (fdptr->read_cb && FD_ISSET(fdptr->fd, &cupsd_current_input))
 716       {
 717         cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Read on fd %d...",
 718                         fdptr->fd);
 719         (*(fdptr->read_cb))(fdptr->data);
 720       }
 721
 722       if (fdptr->write_cb && FD_ISSET(fdptr->fd, &cupsd_current_output))
 723       {
 724         cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDoSelect: Write on fd %d...",
 725                         fdptr->fd);
 726         (*(fdptr->write_cb))(fdptr->data);
 727       }
 728
 729       release_fd(fdptr);
 730     }
 731   }
 732
 733 #endif /* HAVE_KQUEUE */
 734
 735 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 736  /*
 737   * Release all inactive file descriptors...
 738   */
 739
 740 #  ifndef HAVE_KQUEUE
 741   release_inactive:
 742 #  endif /* !HAVE_KQUEUE */
 743
 744   cupsd_in_select = 0;
 745
 746   for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_inactive_fds);
 747        fdptr;
 748        fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_inactive_fds))
 749   {
 750     cupsArrayRemove(cupsd_inactive_fds, fdptr);
 751     release_fd(fdptr);
 752   }
 753 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 754
 755  /*
 756   * Return the number of file descriptors handled...
 757   */
 758
 759   return (nfds);
 760 }
 761
 762
 763 #ifdef CUPSD_IS_SELECTING
 764 /*
 765  * 'cupsdIsSelecting()' - Determine whether we are monitoring a file
 766  *                        descriptor.
 767  */
 768
 769 int                                     /* O - 1 if selecting, 0 otherwise */
 770 cupsdIsSelecting(int fd)                /* I - File descriptor */
 771 {
 772   return (find_fd(fd) != NULL);
 773 }
 774 #endif /* CUPSD_IS_SELECTING */
 775
 776
 777 /*
 778  * 'cupsdRemoveSelect()' - Remove a file descriptor from the list.
 779  */
 780
 781 void
 782 cupsdRemoveSelect(int fd)               /* I - File descriptor */
 783 {
 784   _cupsd_fd_t           *fdptr;         /* File descriptor record */
 785 #ifdef HAVE_EPOLL
 786   struct epoll_event    event;          /* Event data */
 787 #elif defined(HAVE_KQUEUE)
 788   struct kevent         event;          /* Event data */
 789   struct timespec       timeout;        /* Timeout value */
 790 #elif defined(HAVE_POLL)
 791   /* No variables for poll() */
 792 #endif /* HAVE_EPOLL */
 793
 794
 795  /*
 796   * Range check input...
 797   */
 798
 799   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdRemoveSelect: fd=%d", fd);
 800
 801   if (fd < 0)
 802     return;
 803
 804  /*
 805   * Find the file descriptor...
 806   */
 807
 808   if ((fdptr = find_fd(fd)) == NULL)
 809     return;
 810
 811 #ifdef HAVE_EPOLL
 812   if (epoll_ctl(cupsd_epoll_fd, EPOLL_CTL_DEL, fd, &event))
 813   {
 814     close(cupsd_epoll_fd);
 815     cupsd_epoll_fd       = -1;
 816     cupsd_update_pollfds = 1;
 817   }
 818
 819 #elif defined(HAVE_KQUEUE)
 820   timeout.tv_sec  = 0;
 821   timeout.tv_nsec = 0;
 822
 823   if (fdptr->read_cb)
 824   {
 825     EV_SET(&event, fd, EVFILT_READ, EV_DELETE, 0, 0, fdptr);
 826
 827     if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 828     {
 829       cupsdLogMessage(CUPSD_LOG_DEBUG2,
 830                       "cupsdRemoveSelect: kevent() returned %s",
 831                       strerror(errno));
 832       return;
 833     }
 834   }
 835
 836   if (fdptr->write_cb)
 837   {
 838     EV_SET(&event, fd, EVFILT_WRITE, EV_DELETE, 0, 0, fdptr);
 839
 840     if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 841     {
 842       cupsdLogMessage(CUPSD_LOG_DEBUG2,
 843                       "cupsdRemoveSelect: kevent() returned %s",
 844                       strerror(errno));
 845       return;
 846     }
 847   }
 848
 849
 850 #elif defined(HAVE_POLL)
 851  /*
 852   * Update the pollfds array...
 853   */
 854
 855   cupsd_update_pollfds = 1;
 856
 857 #else /* select() */
 858   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 859                   "cupsdRemoveSelect: Removing fd %d from input and output "
 860                   "sets...", fd);
 861   FD_CLR(fd, &cupsd_global_input);
 862   FD_CLR(fd, &cupsd_global_output);
 863   FD_CLR(fd, &cupsd_current_input);
 864   FD_CLR(fd, &cupsd_current_output);
 865 #endif /* HAVE_EPOLL */
 866
 867  /*
 868   * Remove the file descriptor from the active array and add to the
 869   * inactive array (or release, if we don't need the inactive array...)
 870   */
 871
 872   cupsArrayRemove(cupsd_fds, fdptr);
 873
 874 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 875   if (cupsd_in_select)
 876     cupsArrayAdd(cupsd_inactive_fds, fdptr);
 877   else
 878 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 879
 880   release_fd(fdptr);
 881 }
 882
 883
 884 /*
 885  * 'cupsdStartSelect()' - Initialize the file polling engine.
 886  */
 887
 888 void
 889 cupsdStartSelect(void)
 890 {
 891   cupsd_fds = cupsArrayNew((cups_array_func_t)compare_fds, NULL);
 892
 893 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 894   cupsd_inactive_fds = cupsArrayNew((cups_array_func_t)compare_fds, NULL);
 895 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 896
 897 #ifdef HAVE_EPOLL
 898   cupsd_epoll_fd       = epoll_create(MaxFDs);
 899   cupsd_epoll_events   = calloc(MaxFDs, sizeof(struct epoll_event));
 900   cupsd_update_pollfds = 0;
 901
 902 #elif defined(HAVE_KQUEUE)
 903   cupsd_kqueue_fd      = kqueue();
 904   cupsd_kqueue_changes = 0;
 905   cupsd_kqueue_events  = calloc(MaxFDs, sizeof(struct kevent));
 906
 907 #elif defined(HAVE_POLL)
 908   cupsd_update_pollfds = 0;
 909
 910 #else /* select() */
 911   FD_ZERO(&cupsd_global_input);
 912   FD_ZERO(&cupsd_global_output);
 913 #endif /* HAVE_EPOLL */
 914 }
 915
 916
 917 /*
 918  * 'cupsdStopSelect()' - Shutdown the file polling engine.
 919  */
 920
 921 void
 922 cupsdStopSelect(void)
 923 {
 924   _cupsd_fd_t   *fdptr;                 /* Current file descriptor */
 925
 926
 927   for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds);
 928        fdptr;
 929        fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds))
 930     free(fdptr);
 931
 932   cupsArrayDelete(cupsd_fds);
 933   cupsd_fds = NULL;
 934
 935 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 936   cupsArrayDelete(cupsd_inactive_fds);
 937   cupsd_inactive_fds = NULL;
 938 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 939
 940 #ifdef HAVE_KQUEUE
 941   if (cupsd_kqueue_events)
 942   {
 943     free(cupsd_kqueue_events);
 944     cupsd_kqueue_events = NULL;
 945   }
 946
 947   if (cupsd_kqueue_fd >= 0)
 948   {
 949     close(cupsd_kqueue_fd);
 950     cupsd_kqueue_fd = -1;
 951   }
 952
 953   cupsd_kqueue_changes = 0;
 954
 955 #elif defined(HAVE_POLL)
 956 #  ifdef HAVE_EPOLL
 957   if (cupsd_epoll_events)
 958   {
 959     free(cupsd_epoll_events);
 960     cupsd_epoll_events = NULL;
 961   }
 962
 963   if (cupsd_epoll_fd >= 0)
 964   {
 965     close(cupsd_epoll_fd);
 966     cupsd_epoll_fd = -1;
 967   }
 968 #  endif /* HAVE_EPOLL */
 969
 970   if (cupsd_pollfds)
 971   {
 972     free(cupsd_pollfds);
 973     cupsd_pollfds       = NULL;
 974     cupsd_alloc_pollfds = 0;
 975   }
 976
 977   cupsd_update_pollfds = 0;
 978
 979 #else /* select() */
 980   FD_ZERO(&cupsd_global_input);
 981   FD_ZERO(&cupsd_global_output);
 982 #endif /* HAVE_EPOLL */
 983 }
 984
 985
 986 /*
 987  * 'compare_fds()' - Compare file descriptors.
 988  */
 989
 990 static int                              /* O - Result of comparison */
 991 compare_fds(_cupsd_fd_t *a,             /* I - First file descriptor */
 992             _cupsd_fd_t *b)             /* I - Second file descriptor */
 993 {
 994   return (a->fd - b->fd);
 995 }
 996
 997
 998 /*
 999  * 'find_fd()' - Find an existing file descriptor record.
1000  */
1001
1002 static _cupsd_fd_t *                    /* O - FD record pointer or NULL */
1003 find_fd(int fd)                         /* I - File descriptor */
1004 {
1005   _cupsd_fd_t   *fdptr,                 /* Matching record (if any) */
1006                 key;                    /* Search key */
1007
1008
1009   cupsArraySave(cupsd_fds);
1010
1011   key.fd = fd;
1012   fdptr  = (_cupsd_fd_t *)cupsArrayFind(cupsd_fds, &key);
1013
1014   cupsArrayRestore(cupsd_fds);
1015
1016   return (fdptr);
1017 }
1018
1019
1020 /*
1021  * End of "$Id: select.c 7093 2007-11-30 19:09:36Z mike $".
1022  */