scheduler/select.c

   1 /*
   2  * "$Id: select.c 7720 2008-07-11 22:46:21Z mike $"
   3  *
   4  *   Select abstraction functions for the Common UNIX Printing System (CUPS).
   5  *
   6  *   Copyright 2007-2009 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 kqueue() 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 kqueue() 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 #ifdef HAVE_EPOLL
 263   int           added;                  /* 1 if added, 0 if modified */
 264 #endif /* HAVE_EPOLL */
 265
 266
 267  /*
 268   * Range check input...
 269   */
 270
 271   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 272                   "cupsdAddSelect(fd=%d, read_cb=%p, write_cb=%p, data=%p)",
 273                   fd, read_cb, write_cb, data);
 274
 275   if (fd < 0)
 276     return (0);
 277
 278  /*
 279   * See if this FD has already been added...
 280   */
 281
 282   if ((fdptr = find_fd(fd)) == NULL)
 283   {
 284    /*
 285     * No, add a new entry...
 286     */
 287
 288     if ((fdptr = calloc(1, sizeof(_cupsd_fd_t))) == NULL)
 289       return (0);
 290
 291     fdptr->fd  = fd;
 292     fdptr->use = 1;
 293
 294     if (!cupsArrayAdd(cupsd_fds, fdptr))
 295     {
 296       cupsdLogMessage(CUPSD_LOG_EMERG, "Unable to add fd %d to array!", fd);
 297       free(fdptr);
 298       return (0);
 299     }
 300
 301 #ifdef HAVE_EPOLL
 302     added = 1;
 303   }
 304   else
 305     added = 0;
 306 #else
 307   }
 308 #endif /* HAVE_EPOLL */
 309
 310 #ifdef HAVE_KQUEUE
 311   {
 312     struct kevent       event;          /* Event data */
 313     struct timespec     timeout;        /* Timeout value */
 314
 315
 316     timeout.tv_sec  = 0;
 317     timeout.tv_nsec = 0;
 318
 319     if (fdptr->read_cb != read_cb)
 320     {
 321       if (read_cb)
 322         EV_SET(&event, fd, EVFILT_READ, EV_ADD, 0, 0, fdptr);
 323       else
 324         EV_SET(&event, fd, EVFILT_READ, EV_DELETE, 0, 0, fdptr);
 325
 326       if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 327       {
 328         cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
 329                         strerror(errno));
 330         return (0);
 331       }
 332     }
 333
 334     if (fdptr->write_cb != write_cb)
 335     {
 336       if (write_cb)
 337         EV_SET(&event, fd, EVFILT_WRITE, EV_ADD, 0, 0, fdptr);
 338       else
 339         EV_SET(&event, fd, EVFILT_WRITE, EV_DELETE, 0, 0, fdptr);
 340
 341       if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 342       {
 343         cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
 344                         strerror(errno));
 345         return (0);
 346       }
 347     }
 348   }
 349
 350 #elif defined(HAVE_POLL)
 351 #  ifdef HAVE_EPOLL
 352   if (cupsd_epoll_fd >= 0)
 353   {
 354     struct epoll_event event;           /* Event data */
 355
 356
 357     event.events = 0;
 358
 359     if (read_cb)
 360       event.events |= EPOLLIN;
 361
 362     if (write_cb)
 363       event.events |= EPOLLOUT;
 364
 365     event.data.ptr = fdptr;
 366
 367     if (epoll_ctl(cupsd_epoll_fd, added ? EPOLL_CTL_ADD : EPOLL_CTL_MOD, fd,
 368                   &event))
 369     {
 370       close(cupsd_epoll_fd);
 371       cupsd_epoll_fd       = -1;
 372       cupsd_update_pollfds = 1;
 373     }
 374   }
 375   else
 376 #  endif /* HAVE_EPOLL */
 377
 378   cupsd_update_pollfds = 1;
 379
 380 #else /* select() */
 381  /*
 382   * Add or remove the file descriptor in the input and output sets
 383   * for select()...
 384   */
 385
 386   if (read_cb)
 387     FD_SET(fd, &cupsd_global_input);
 388   else
 389   {
 390     FD_CLR(fd, &cupsd_global_input);
 391     FD_CLR(fd, &cupsd_current_input);
 392   }
 393
 394   if (write_cb)
 395     FD_SET(fd, &cupsd_global_output);
 396   else
 397   {
 398     FD_CLR(fd, &cupsd_global_output);
 399     FD_CLR(fd, &cupsd_current_output);
 400   }
 401 #endif /* HAVE_KQUEUE */
 402
 403  /*
 404   * Save the (new) read and write callbacks...
 405   */
 406
 407   fdptr->read_cb  = read_cb;
 408   fdptr->write_cb = write_cb;
 409   fdptr->data     = data;
 410
 411   return (1);
 412 }
 413
 414
 415 /*
 416  * 'cupsdDoSelect()' - Do a select-like operation.
 417  */
 418
 419 int                                     /* O - Number of files or -1 on error */
 420 cupsdDoSelect(long timeout)             /* I - Timeout in seconds */
 421 {
 422   int                   nfds;           /* Number of file descriptors */
 423   _cupsd_fd_t           *fdptr;         /* Current file descriptor */
 424 #ifdef HAVE_KQUEUE
 425   int                   i;              /* Looping var */
 426   struct kevent         *event;         /* Current event */
 427   struct timespec       ktimeout;       /* kevent() timeout */
 428
 429
 430   cupsd_in_select = 1;
 431
 432   if (timeout >= 0 && timeout < 86400)
 433   {
 434     ktimeout.tv_sec  = timeout;
 435     ktimeout.tv_nsec = 0;
 436
 437     nfds = kevent(cupsd_kqueue_fd, NULL, 0, cupsd_kqueue_events, MaxFDs,
 438                   &ktimeout);
 439   }
 440   else
 441     nfds = kevent(cupsd_kqueue_fd, NULL, 0, cupsd_kqueue_events, MaxFDs, NULL);
 442
 443   cupsd_kqueue_changes = 0;
 444
 445   for (i = nfds, event = cupsd_kqueue_events; i > 0; i --, event ++)
 446   {
 447     fdptr = (_cupsd_fd_t *)event->udata;
 448
 449     if (cupsArrayFind(cupsd_inactive_fds, fdptr))
 450       continue;
 451
 452     retain_fd(fdptr);
 453
 454     if (fdptr->read_cb && event->filter == EVFILT_READ)
 455       (*(fdptr->read_cb))(fdptr->data);
 456
 457     if (fdptr->use > 1 && fdptr->write_cb && event->filter == EVFILT_WRITE)
 458       (*(fdptr->write_cb))(fdptr->data);
 459
 460     release_fd(fdptr);
 461   }
 462
 463 #elif defined(HAVE_POLL)
 464   struct pollfd         *pfd;           /* Current pollfd structure */
 465   int                   count;          /* Number of file descriptors */
 466
 467
 468 #  ifdef HAVE_EPOLL
 469   cupsd_in_select = 1;
 470
 471   if (cupsd_epoll_fd >= 0)
 472   {
 473     int                 i;              /* Looping var */
 474     struct epoll_event  *event;         /* Current event */
 475
 476
 477     if (timeout >= 0 && timeout < 86400)
 478       nfds = epoll_wait(cupsd_epoll_fd, cupsd_epoll_events, MaxFDs,
 479                         timeout * 1000);
 480     else
 481       nfds = epoll_wait(cupsd_epoll_fd, cupsd_epoll_events, MaxFDs, -1);
 482
 483     if (nfds < 0 && errno != EINTR)
 484     {
 485       close(cupsd_epoll_fd);
 486       cupsd_epoll_fd = -1;
 487     }
 488     else
 489     {
 490       for (i = nfds, event = cupsd_epoll_events; i > 0; i --, event ++)
 491       {
 492         fdptr = (_cupsd_fd_t *)event->data.ptr;
 493
 494         if (cupsArrayFind(cupsd_inactive_fds, fdptr))
 495           continue;
 496
 497         retain_fd(fdptr);
 498
 499         if (fdptr->read_cb && (event->events & (EPOLLIN | EPOLLERR | EPOLLHUP)))
 500           (*(fdptr->read_cb))(fdptr->data);
 501
 502         if (fdptr->use > 1 && fdptr->write_cb &&
 503             (event->events & (EPOLLOUT | EPOLLERR | EPOLLHUP)))
 504           (*(fdptr->write_cb))(fdptr->data);
 505
 506         release_fd(fdptr);
 507       }
 508
 509       goto release_inactive;
 510     }
 511   }
 512 #  endif /* HAVE_EPOLL */
 513
 514   count = cupsArrayCount(cupsd_fds);
 515
 516   if (cupsd_update_pollfds)
 517   {
 518    /*
 519     * Update the cupsd_pollfds array to match the current FD array...
 520     */
 521
 522     cupsd_update_pollfds = 0;
 523
 524    /*
 525     * (Re)allocate memory as needed...
 526     */
 527
 528     if (count > cupsd_alloc_pollfds)
 529     {
 530       int allocfds = count + 16;
 531
 532
 533       if (cupsd_pollfds)
 534         pfd = realloc(cupsd_pollfds, allocfds * sizeof(struct pollfd));
 535       else
 536         pfd = malloc(allocfds * sizeof(struct pollfd));
 537
 538       if (!pfd)
 539       {
 540         cupsdLogMessage(CUPSD_LOG_EMERG,
 541                         "Unable to allocate %d bytes for polling!",
 542                         (int)(allocfds * sizeof(struct pollfd)));
 543
 544         return (-1);
 545       }
 546
 547       cupsd_pollfds       = pfd;
 548       cupsd_alloc_pollfds = allocfds;
 549     }
 550
 551    /*
 552     * Rebuild the array...
 553     */
 554
 555     for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds), pfd = cupsd_pollfds;
 556          fdptr;
 557          fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds), pfd ++)
 558     {
 559       pfd->fd      = fdptr->fd;
 560       pfd->events  = 0;
 561
 562       if (fdptr->read_cb)
 563         pfd->events |= POLLIN;
 564
 565       if (fdptr->write_cb)
 566         pfd->events |= POLLOUT;
 567     }
 568   }
 569
 570   if (timeout >= 0 && timeout < 86400)
 571     nfds = poll(cupsd_pollfds, count, timeout * 1000);
 572   else
 573     nfds = poll(cupsd_pollfds, count, -1);
 574
 575   if (nfds > 0)
 576   {
 577    /*
 578     * Do callbacks for each file descriptor...
 579     */
 580
 581     for (pfd = cupsd_pollfds; count > 0; pfd ++, count --)
 582     {
 583       if (!pfd->revents)
 584         continue;
 585
 586       if ((fdptr = find_fd(pfd->fd)) == NULL)
 587         continue;
 588
 589       retain_fd(fdptr);
 590
 591       if (fdptr->read_cb && (pfd->revents & (POLLIN | POLLERR | POLLHUP)))
 592         (*(fdptr->read_cb))(fdptr->data);
 593
 594       if (fdptr->use > 1 && fdptr->write_cb &&
 595           (pfd->revents & (POLLOUT | POLLERR | POLLHUP)))
 596         (*(fdptr->write_cb))(fdptr->data);
 597
 598       release_fd(fdptr);
 599     }
 600   }
 601
 602 #else /* select() */
 603   struct timeval        stimeout;       /* Timeout for select() */
 604   int                   maxfd;          /* Maximum file descriptor */
 605
 606
 607  /*
 608   * Figure out the highest file descriptor number...
 609   */
 610
 611   if ((fdptr = (_cupsd_fd_t *)cupsArrayLast(cupsd_fds)) == NULL)
 612     maxfd = 1;
 613   else
 614     maxfd = fdptr->fd + 1;
 615
 616  /*
 617   * Do the select()...
 618   */
 619
 620   cupsd_current_input  = cupsd_global_input;
 621   cupsd_current_output = cupsd_global_output;
 622
 623   if (timeout >= 0 && timeout < 86400)
 624   {
 625     stimeout.tv_sec  = timeout;
 626     stimeout.tv_usec = 0;
 627
 628     nfds = select(maxfd, &cupsd_current_input, &cupsd_current_output, NULL,
 629                   &stimeout);
 630   }
 631   else
 632     nfds = select(maxfd, &cupsd_current_input, &cupsd_current_output, NULL,
 633                   NULL);
 634
 635   if (nfds > 0)
 636   {
 637    /*
 638     * Do callbacks for each file descriptor...
 639     */
 640
 641     for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds);
 642          fdptr;
 643          fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds))
 644     {
 645       retain_fd(fdptr);
 646
 647       if (fdptr->read_cb && FD_ISSET(fdptr->fd, &cupsd_current_input))
 648         (*(fdptr->read_cb))(fdptr->data);
 649
 650       if (fdptr->use > 1 && fdptr->write_cb &&
 651           FD_ISSET(fdptr->fd, &cupsd_current_output))
 652         (*(fdptr->write_cb))(fdptr->data);
 653
 654       release_fd(fdptr);
 655     }
 656   }
 657
 658 #endif /* HAVE_KQUEUE */
 659
 660 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 661  /*
 662   * Release all inactive file descriptors...
 663   */
 664
 665 #  ifndef HAVE_KQUEUE
 666   release_inactive:
 667 #  endif /* !HAVE_KQUEUE */
 668
 669   cupsd_in_select = 0;
 670
 671   for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_inactive_fds);
 672        fdptr;
 673        fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_inactive_fds))
 674   {
 675     cupsArrayRemove(cupsd_inactive_fds, fdptr);
 676     release_fd(fdptr);
 677   }
 678 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 679
 680  /*
 681   * Return the number of file descriptors handled...
 682   */
 683
 684   return (nfds);
 685 }
 686
 687
 688 #ifdef CUPSD_IS_SELECTING
 689 /*
 690  * 'cupsdIsSelecting()' - Determine whether we are monitoring a file
 691  *                        descriptor.
 692  */
 693
 694 int                                     /* O - 1 if selecting, 0 otherwise */
 695 cupsdIsSelecting(int fd)                /* I - File descriptor */
 696 {
 697   return (find_fd(fd) != NULL);
 698 }
 699 #endif /* CUPSD_IS_SELECTING */
 700
 701
 702 /*
 703  * 'cupsdRemoveSelect()' - Remove a file descriptor from the list.
 704  */
 705
 706 void
 707 cupsdRemoveSelect(int fd)               /* I - File descriptor */
 708 {
 709   _cupsd_fd_t           *fdptr;         /* File descriptor record */
 710 #ifdef HAVE_EPOLL
 711   struct epoll_event    event;          /* Event data */
 712 #elif defined(HAVE_KQUEUE)
 713   struct kevent         event;          /* Event data */
 714   struct timespec       timeout;        /* Timeout value */
 715 #elif defined(HAVE_POLL)
 716   /* No variables for poll() */
 717 #endif /* HAVE_EPOLL */
 718
 719
 720  /*
 721   * Range check input...
 722   */
 723
 724   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdRemoveSelect(fd=%d)", fd);
 725
 726   if (fd < 0)
 727     return;
 728
 729  /*
 730   * Find the file descriptor...
 731   */
 732
 733   if ((fdptr = find_fd(fd)) == NULL)
 734     return;
 735
 736 #ifdef HAVE_EPOLL
 737   if (epoll_ctl(cupsd_epoll_fd, EPOLL_CTL_DEL, fd, &event))
 738   {
 739     close(cupsd_epoll_fd);
 740     cupsd_epoll_fd       = -1;
 741     cupsd_update_pollfds = 1;
 742   }
 743
 744 #elif defined(HAVE_KQUEUE)
 745   timeout.tv_sec  = 0;
 746   timeout.tv_nsec = 0;
 747
 748   if (fdptr->read_cb)
 749   {
 750     EV_SET(&event, fd, EVFILT_READ, EV_DELETE, 0, 0, fdptr);
 751
 752     if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 753     {
 754       cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
 755                       strerror(errno));
 756       goto cleanup;
 757     }
 758   }
 759
 760   if (fdptr->write_cb)
 761   {
 762     EV_SET(&event, fd, EVFILT_WRITE, EV_DELETE, 0, 0, fdptr);
 763
 764     if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
 765     {
 766       cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
 767                       strerror(errno));
 768       goto cleanup;
 769     }
 770   }
 771
 772 #elif defined(HAVE_POLL)
 773  /*
 774   * Update the pollfds array...
 775   */
 776
 777   cupsd_update_pollfds = 1;
 778
 779 #else /* select() */
 780   FD_CLR(fd, &cupsd_global_input);
 781   FD_CLR(fd, &cupsd_global_output);
 782   FD_CLR(fd, &cupsd_current_input);
 783   FD_CLR(fd, &cupsd_current_output);
 784 #endif /* HAVE_EPOLL */
 785
 786 #ifdef HAVE_KQUEUE
 787   cleanup:
 788 #endif /* HAVE_KQUEUE */
 789
 790  /*
 791   * Remove the file descriptor from the active array and add to the
 792   * inactive array (or release, if we don't need the inactive array...)
 793   */
 794
 795   cupsArrayRemove(cupsd_fds, fdptr);
 796
 797 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 798   if (cupsd_in_select)
 799     cupsArrayAdd(cupsd_inactive_fds, fdptr);
 800   else
 801 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 802
 803   release_fd(fdptr);
 804 }
 805
 806
 807 /*
 808  * 'cupsdStartSelect()' - Initialize the file polling engine.
 809  */
 810
 811 void
 812 cupsdStartSelect(void)
 813 {
 814   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdStartSelect()");
 815
 816   cupsd_fds = cupsArrayNew((cups_array_func_t)compare_fds, NULL);
 817
 818 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 819   cupsd_inactive_fds = cupsArrayNew((cups_array_func_t)compare_fds, NULL);
 820 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 821
 822 #ifdef HAVE_EPOLL
 823   cupsd_epoll_fd       = epoll_create(MaxFDs);
 824   cupsd_epoll_events   = calloc(MaxFDs, sizeof(struct epoll_event));
 825   cupsd_update_pollfds = 0;
 826
 827 #elif defined(HAVE_KQUEUE)
 828   cupsd_kqueue_fd      = kqueue();
 829   cupsd_kqueue_changes = 0;
 830   cupsd_kqueue_events  = calloc(MaxFDs, sizeof(struct kevent));
 831
 832 #elif defined(HAVE_POLL)
 833   cupsd_update_pollfds = 0;
 834
 835 #else /* select() */
 836   FD_ZERO(&cupsd_global_input);
 837   FD_ZERO(&cupsd_global_output);
 838 #endif /* HAVE_EPOLL */
 839 }
 840
 841
 842 /*
 843  * 'cupsdStopSelect()' - Shutdown the file polling engine.
 844  */
 845
 846 void
 847 cupsdStopSelect(void)
 848 {
 849   _cupsd_fd_t   *fdptr;                 /* Current file descriptor */
 850
 851
 852   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdStopSelect()");
 853
 854   for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds);
 855        fdptr;
 856        fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds))
 857     free(fdptr);
 858
 859   cupsArrayDelete(cupsd_fds);
 860   cupsd_fds = NULL;
 861
 862 #if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
 863   cupsArrayDelete(cupsd_inactive_fds);
 864   cupsd_inactive_fds = NULL;
 865 #endif /* HAVE_EPOLL || HAVE_KQUEUE */
 866
 867 #ifdef HAVE_KQUEUE
 868   if (cupsd_kqueue_events)
 869   {
 870     free(cupsd_kqueue_events);
 871     cupsd_kqueue_events = NULL;
 872   }
 873
 874   if (cupsd_kqueue_fd >= 0)
 875   {
 876     close(cupsd_kqueue_fd);
 877     cupsd_kqueue_fd = -1;
 878   }
 879
 880   cupsd_kqueue_changes = 0;
 881
 882 #elif defined(HAVE_POLL)
 883 #  ifdef HAVE_EPOLL
 884   if (cupsd_epoll_events)
 885   {
 886     free(cupsd_epoll_events);
 887     cupsd_epoll_events = NULL;
 888   }
 889
 890   if (cupsd_epoll_fd >= 0)
 891   {
 892     close(cupsd_epoll_fd);
 893     cupsd_epoll_fd = -1;
 894   }
 895 #  endif /* HAVE_EPOLL */
 896
 897   if (cupsd_pollfds)
 898   {
 899     free(cupsd_pollfds);
 900     cupsd_pollfds       = NULL;
 901     cupsd_alloc_pollfds = 0;
 902   }
 903
 904   cupsd_update_pollfds = 0;
 905
 906 #else /* select() */
 907   FD_ZERO(&cupsd_global_input);
 908   FD_ZERO(&cupsd_global_output);
 909 #endif /* HAVE_EPOLL */
 910 }
 911
 912
 913 /*
 914  * 'compare_fds()' - Compare file descriptors.
 915  */
 916
 917 static int                              /* O - Result of comparison */
 918 compare_fds(_cupsd_fd_t *a,             /* I - First file descriptor */
 919             _cupsd_fd_t *b)             /* I - Second file descriptor */
 920 {
 921   return (a->fd - b->fd);
 922 }
 923
 924
 925 /*
 926  * 'find_fd()' - Find an existing file descriptor record.
 927  */
 928
 929 static _cupsd_fd_t *                    /* O - FD record pointer or NULL */
 930 find_fd(int fd)                         /* I - File descriptor */
 931 {
 932   _cupsd_fd_t   *fdptr,                 /* Matching record (if any) */
 933                 key;                    /* Search key */
 934
 935
 936   cupsArraySave(cupsd_fds);
 937
 938   key.fd = fd;
 939   fdptr  = (_cupsd_fd_t *)cupsArrayFind(cupsd_fds, &key);
 940
 941   cupsArrayRestore(cupsd_fds);
 942
 943   return (fdptr);
 944 }
 945
 946
 947 /*
 948  * End of "$Id: select.c 7720 2008-07-11 22:46:21Z mike $".
 949  */