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cups/scheduler/select.c

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/*
* Select abstraction functions for the CUPS scheduler.
*
* Copyright 2007-2016 by Apple Inc.
* Copyright 2006-2007 by Easy Software Products.
*
* Licensed under Apache License v2.0. See the file "LICENSE" for more information.
*/
/*
* Include necessary headers...
*/
#include "cupsd.h"
#ifdef HAVE_EPOLL
# include <sys/epoll.h>
# include <poll.h>
#elif defined(HAVE_KQUEUE)
# include <sys/event.h>
# include <sys/time.h>
#elif defined(HAVE_POLL)
# include <poll.h>
#else
# include <sys/select.h>
#endif /* HAVE_EPOLL */
/*
* Design Notes for Poll/Select API in CUPSD
* -----------------------------------------
*
* SUPPORTED APIS
*
* OS select poll epoll kqueue /dev/poll
* -------------- ------ ------ ------ ------ ---------
* AIX YES YES NO NO NO
* FreeBSD YES YES NO YES NO
* HP-UX YES YES NO NO NO
* Linux YES YES YES NO NO
* macOS YES YES NO YES NO
* NetBSD YES YES NO YES NO
* OpenBSD YES YES NO YES NO
* Solaris YES YES NO NO YES
* Tru64 YES YES NO NO NO
* Windows YES NO NO NO NO
*
*
* HIGH-LEVEL API
*
* typedef void (*cupsd_selfunc_t)(void *data);
*
* void cupsdStartSelect(void);
* void cupsdStopSelect(void);
* void cupsdAddSelect(int fd, cupsd_selfunc_t read_cb,
* cupsd_selfunc_t write_cb, void *data);
* void cupsdRemoveSelect(int fd);
* int cupsdDoSelect(int timeout);
*
*
* IMPLEMENTATION STRATEGY
*
* 0. Common Stuff
* a. CUPS array of file descriptor to callback functions
* and data + temporary array of removed fd's.
* b. cupsdStartSelect() creates the arrays
* c. cupsdStopSelect() destroys the arrays and all elements.
* d. cupsdAddSelect() adds to the array and allocates a
* new callback element.
* e. cupsdRemoveSelect() removes from the active array and
* adds to the inactive array.
* f. _cupsd_fd_t provides a reference-counted structure for
* tracking file descriptors that are monitored.
* g. cupsdDoSelect() frees all inactive FDs.
*
* 1. select() O(n)
* a. Input/Output fd_set variables, copied to working
* copies and then used with select().
* b. Loop through CUPS array, using FD_ISSET and calling
* the read/write callbacks as needed.
* c. cupsdRemoveSelect() clears fd_set bit from main and
* working sets.
* d. cupsdStopSelect() frees all of the memory used by the
* CUPS array and fd_set's.
*
* 2. poll() - O(n log n)
* a. Regular array of pollfd, sorted the same as the CUPS
* array.
* b. Loop through pollfd array, call the corresponding
* read/write callbacks as needed.
* c. cupsdAddSelect() adds first to CUPS array and flags the
* pollfd array as invalid.
* d. cupsdDoSelect() rebuilds pollfd array as needed, calls
* poll(), then loops through the pollfd array looking up
* as needed.
* e. cupsdRemoveSelect() flags the pollfd array as invalid.
* f. cupsdStopSelect() frees all of the memory used by the
* CUPS array and pollfd array.
*
* 3. epoll() - O(n)
* a. cupsdStartSelect() creates epoll file descriptor using
* epoll_create() with the maximum fd count, and
* allocates an events buffer for the maximum fd count.
* b. cupsdAdd/RemoveSelect() uses epoll_ctl() to add
* (EPOLL_CTL_ADD) or remove (EPOLL_CTL_DEL) a single
* event using the level-triggered semantics. The event
* user data field is a pointer to the new callback array
* element.
* c. cupsdDoSelect() uses epoll_wait() with the global event
* buffer allocated in cupsdStartSelect() and then loops
* through the events, using the user data field to find
* the callback record.
* d. cupsdStopSelect() closes the epoll file descriptor and
* frees all of the memory used by the event buffer.
*
* 4. kqueue() - O(n)
* b. cupsdStartSelect() creates kqueue file descriptor
* using kqueue() function and allocates a global event
* buffer.
* c. cupsdAdd/RemoveSelect() uses EV_SET and kevent() to
* register the changes. The event user data field is a
* pointer to the new callback array element.
* d. cupsdDoSelect() uses kevent() to poll for events and
* loops through the events, using the user data field to
* find the callback record.
* e. cupsdStopSelect() closes the kqueue() file descriptor
* and frees all of the memory used by the event buffer.
*
* 5. /dev/poll - O(n log n) - NOT YET IMPLEMENTED
* a. cupsdStartSelect() opens /dev/poll and allocates an
* array of pollfd structs; on failure to open /dev/poll,
* revert to poll() system call.
* b. cupsdAddSelect() writes a single pollfd struct to
* /dev/poll with the new file descriptor and the
* POLLIN/POLLOUT flags.
* c. cupsdRemoveSelect() writes a single pollfd struct to
* /dev/poll with the file descriptor and the POLLREMOVE
* flag.
* d. cupsdDoSelect() uses the DP_POLL ioctl to retrieve
* events from /dev/poll and then loops through the
* returned pollfd array, looking up the file descriptors
* as needed.
* e. cupsdStopSelect() closes /dev/poll and frees the
* pollfd array.
*
* PERFORMANCE
*
* In tests using the "make test" target with option 0 (keep cupsd
* running) and the "testspeed" program with "-c 50 -r 1000", epoll()
* performed 5.5% slower than select(), followed by kqueue() at 16%
* slower than select() and poll() at 18% slower than select(). Similar
* results were seen with twice the number of client connections.
*
* The epoll() and kqueue() performance is likely limited by the
* number of system calls used to add/modify/remove file
* descriptors dynamically. Further optimizations may be possible
* in the area of limiting use of cupsdAddSelect() and
* cupsdRemoveSelect(), however extreme care will be needed to avoid
* excess CPU usage and deadlock conditions.
*
* We may be able to improve the poll() implementation simply by
* keeping the pollfd array sync'd with the _cupsd_fd_t array, as that
* will eliminate the rebuilding of the array whenever there is a
* change and eliminate the fd array lookups in the inner loop of
* cupsdDoSelect().
*
* Since /dev/poll will never be able to use a shadow array, it may
* not make sense to implement support for it. ioctl() overhead will
* impact performance as well, so my guess would be that, for CUPS,
* /dev/poll will yield a net performance loss.
*/
/*
* Local structures...
*/
typedef struct _cupsd_fd_s
{
int fd, /* File descriptor */
use; /* Use count */
cupsd_selfunc_t read_cb, /* Read callback */
write_cb; /* Write callback */
void *data; /* Data pointer for callbacks */
} _cupsd_fd_t;
/*
* Local globals...
*/
static cups_array_t *cupsd_fds = NULL;
#if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
static cups_array_t *cupsd_inactive_fds = NULL;
static int cupsd_in_select = 0;
#endif /* HAVE_EPOLL || HAVE_KQUEUE */
#ifdef HAVE_KQUEUE
static int cupsd_kqueue_fd = -1;
static struct kevent *cupsd_kqueue_events = NULL;
#elif defined(HAVE_POLL)
static int cupsd_alloc_pollfds = 0,
cupsd_update_pollfds = 0;
static struct pollfd *cupsd_pollfds = NULL;
# ifdef HAVE_EPOLL
static int cupsd_epoll_fd = -1;
static struct epoll_event *cupsd_epoll_events = NULL;
# endif /* HAVE_EPOLL */
#else /* select() */
static fd_set cupsd_global_input,
cupsd_global_output,
cupsd_current_input,
cupsd_current_output;
#endif /* HAVE_KQUEUE */
/*
* Local functions...
*/
static int compare_fds(_cupsd_fd_t *a, _cupsd_fd_t *b);
static _cupsd_fd_t *find_fd(int fd);
#define release_fd(f) { \
(f)->use --; \
if (!(f)->use) free((f));\
}
#define retain_fd(f) (f)->use++
/*
* 'cupsdAddSelect()' - Add a file descriptor to the list.
*/
int /* O - 1 on success, 0 on error */
cupsdAddSelect(int fd, /* I - File descriptor */
cupsd_selfunc_t read_cb, /* I - Read callback */
cupsd_selfunc_t write_cb,/* I - Write callback */
void *data) /* I - Data to pass to callback */
{
_cupsd_fd_t *fdptr; /* File descriptor record */
#ifdef HAVE_EPOLL
int added; /* 1 if added, 0 if modified */
#endif /* HAVE_EPOLL */
/*
* Range check input...
*/
cupsdLogMessage(CUPSD_LOG_DEBUG2,
"cupsdAddSelect(fd=%d, read_cb=%p, write_cb=%p, data=%p)",
fd, read_cb, write_cb, data);
if (fd < 0)
return (0);
/*
* See if this FD has already been added...
*/
if ((fdptr = find_fd(fd)) == NULL)
{
/*
* No, add a new entry...
*/
if ((fdptr = calloc(1, sizeof(_cupsd_fd_t))) == NULL)
return (0);
fdptr->fd = fd;
fdptr->use = 1;
if (!cupsArrayAdd(cupsd_fds, fdptr))
{
cupsdLogMessage(CUPSD_LOG_EMERG, "Unable to add fd %d to array!", fd);
free(fdptr);
return (0);
}
#ifdef HAVE_EPOLL
added = 1;
}
else
added = 0;
#else
}
#endif /* HAVE_EPOLL */
#ifdef HAVE_KQUEUE
{
struct kevent event; /* Event data */
struct timespec timeout; /* Timeout value */
timeout.tv_sec = 0;
timeout.tv_nsec = 0;
if (fdptr->read_cb != read_cb)
{
if (read_cb)
EV_SET(&event, fd, EVFILT_READ, EV_ADD, 0, 0, fdptr);
else
EV_SET(&event, fd, EVFILT_READ, EV_DELETE, 0, 0, fdptr);
if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
{
cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
strerror(errno));
return (0);
}
}
if (fdptr->write_cb != write_cb)
{
if (write_cb)
EV_SET(&event, fd, EVFILT_WRITE, EV_ADD, 0, 0, fdptr);
else
EV_SET(&event, fd, EVFILT_WRITE, EV_DELETE, 0, 0, fdptr);
if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
{
cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
strerror(errno));
return (0);
}
}
}
#elif defined(HAVE_POLL)
# ifdef HAVE_EPOLL
if (cupsd_epoll_fd >= 0)
{
struct epoll_event event; /* Event data */
event.events = 0;
if (read_cb)
event.events |= EPOLLIN;
if (write_cb)
event.events |= EPOLLOUT;
event.data.ptr = fdptr;
if (epoll_ctl(cupsd_epoll_fd, added ? EPOLL_CTL_ADD : EPOLL_CTL_MOD, fd,
&event))
{
close(cupsd_epoll_fd);
cupsd_epoll_fd = -1;
cupsd_update_pollfds = 1;
}
}
else
# endif /* HAVE_EPOLL */
cupsd_update_pollfds = 1;
#else /* select() */
/*
* Add or remove the file descriptor in the input and output sets
* for select()...
*/
if (read_cb)
FD_SET(fd, &cupsd_global_input);
else
{
FD_CLR(fd, &cupsd_global_input);
FD_CLR(fd, &cupsd_current_input);
}
if (write_cb)
FD_SET(fd, &cupsd_global_output);
else
{
FD_CLR(fd, &cupsd_global_output);
FD_CLR(fd, &cupsd_current_output);
}
#endif /* HAVE_KQUEUE */
/*
* Save the (new) read and write callbacks...
*/
fdptr->read_cb = read_cb;
fdptr->write_cb = write_cb;
fdptr->data = data;
return (1);
}
/*
* 'cupsdDoSelect()' - Do a select-like operation.
*/
int /* O - Number of files or -1 on error */
cupsdDoSelect(long timeout) /* I - Timeout in seconds */
{
int nfds; /* Number of file descriptors */
_cupsd_fd_t *fdptr; /* Current file descriptor */
#ifdef HAVE_KQUEUE
int i; /* Looping var */
struct kevent *event; /* Current event */
struct timespec ktimeout; /* kevent() timeout */
cupsd_in_select = 1;
if (timeout >= 0 && timeout < 86400)
{
ktimeout.tv_sec = timeout;
ktimeout.tv_nsec = 0;
nfds = kevent(cupsd_kqueue_fd, NULL, 0, cupsd_kqueue_events, MaxFDs,
&ktimeout);
}
else
nfds = kevent(cupsd_kqueue_fd, NULL, 0, cupsd_kqueue_events, MaxFDs, NULL);
for (i = nfds, event = cupsd_kqueue_events; i > 0; i --, event ++)
{
fdptr = (_cupsd_fd_t *)event->udata;
if (cupsArrayFind(cupsd_inactive_fds, fdptr))
continue;
retain_fd(fdptr);
if (fdptr->read_cb && event->filter == EVFILT_READ)
(*(fdptr->read_cb))(fdptr->data);
if (fdptr->use > 1 && fdptr->write_cb && event->filter == EVFILT_WRITE &&
!cupsArrayFind(cupsd_inactive_fds, fdptr))
(*(fdptr->write_cb))(fdptr->data);
release_fd(fdptr);
}
#elif defined(HAVE_POLL)
struct pollfd *pfd; /* Current pollfd structure */
int count; /* Number of file descriptors */
# ifdef HAVE_EPOLL
cupsd_in_select = 1;
if (cupsd_epoll_fd >= 0)
{
int i; /* Looping var */
struct epoll_event *event; /* Current event */
if (timeout >= 0 && timeout < 86400)
nfds = epoll_wait(cupsd_epoll_fd, cupsd_epoll_events, MaxFDs,
timeout * 1000);
else
nfds = epoll_wait(cupsd_epoll_fd, cupsd_epoll_events, MaxFDs, -1);
if (nfds < 0 && errno != EINTR)
{
close(cupsd_epoll_fd);
cupsd_epoll_fd = -1;
}
else
{
for (i = nfds, event = cupsd_epoll_events; i > 0; i --, event ++)
{
fdptr = (_cupsd_fd_t *)event->data.ptr;
if (cupsArrayFind(cupsd_inactive_fds, fdptr))
continue;
retain_fd(fdptr);
if (fdptr->read_cb && (event->events & (EPOLLIN | EPOLLERR | EPOLLHUP)))
(*(fdptr->read_cb))(fdptr->data);
if (fdptr->use > 1 && fdptr->write_cb &&
(event->events & (EPOLLOUT | EPOLLERR | EPOLLHUP)) &&
!cupsArrayFind(cupsd_inactive_fds, fdptr))
(*(fdptr->write_cb))(fdptr->data);
release_fd(fdptr);
}
goto release_inactive;
}
}
# endif /* HAVE_EPOLL */
count = cupsArrayCount(cupsd_fds);
if (cupsd_update_pollfds)
{
/*
* Update the cupsd_pollfds array to match the current FD array...
*/
cupsd_update_pollfds = 0;
/*
* (Re)allocate memory as needed...
*/
if (count > cupsd_alloc_pollfds)
{
int allocfds = count + 16;
if (cupsd_pollfds)
pfd = realloc(cupsd_pollfds, (size_t)allocfds * sizeof(struct pollfd));
else
pfd = malloc((size_t)allocfds * sizeof(struct pollfd));
if (!pfd)
{
cupsdLogMessage(CUPSD_LOG_EMERG, "Unable to allocate %d bytes for polling.", (int)((size_t)allocfds * sizeof(struct pollfd)));
return (-1);
}
cupsd_pollfds = pfd;
cupsd_alloc_pollfds = allocfds;
}
/*
* Rebuild the array...
*/
for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds), pfd = cupsd_pollfds;
fdptr;
fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds), pfd ++)
{
pfd->fd = fdptr->fd;
pfd->events = 0;
if (fdptr->read_cb)
pfd->events |= POLLIN;
if (fdptr->write_cb)
pfd->events |= POLLOUT;
}
}
if (timeout >= 0 && timeout < 86400)
nfds = poll(cupsd_pollfds, (nfds_t)count, timeout * 1000);
else
nfds = poll(cupsd_pollfds, (nfds_t)count, -1);
if (nfds > 0)
{
/*
* Do callbacks for each file descriptor...
*/
for (pfd = cupsd_pollfds; count > 0; pfd ++, count --)
{
if (!pfd->revents)
continue;
if ((fdptr = find_fd(pfd->fd)) == NULL)
continue;
retain_fd(fdptr);
if (fdptr->read_cb && (pfd->revents & (POLLIN | POLLERR | POLLHUP)))
(*(fdptr->read_cb))(fdptr->data);
if (fdptr->use > 1 && fdptr->write_cb &&
(pfd->revents & (POLLOUT | POLLERR | POLLHUP)))
(*(fdptr->write_cb))(fdptr->data);
release_fd(fdptr);
}
}
#else /* select() */
struct timeval stimeout; /* Timeout for select() */
int maxfd; /* Maximum file descriptor */
/*
* Figure out the highest file descriptor number...
*/
if ((fdptr = (_cupsd_fd_t *)cupsArrayLast(cupsd_fds)) == NULL)
maxfd = 1;
else
maxfd = fdptr->fd + 1;
/*
* Do the select()...
*/
cupsd_current_input = cupsd_global_input;
cupsd_current_output = cupsd_global_output;
if (timeout >= 0 && timeout < 86400)
{
stimeout.tv_sec = timeout;
stimeout.tv_usec = 0;
nfds = select(maxfd, &cupsd_current_input, &cupsd_current_output, NULL,
&stimeout);
}
else
nfds = select(maxfd, &cupsd_current_input, &cupsd_current_output, NULL,
NULL);
if (nfds > 0)
{
/*
* Do callbacks for each file descriptor...
*/
for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds);
fdptr;
fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds))
{
retain_fd(fdptr);
if (fdptr->read_cb && FD_ISSET(fdptr->fd, &cupsd_current_input))
(*(fdptr->read_cb))(fdptr->data);
if (fdptr->use > 1 && fdptr->write_cb &&
FD_ISSET(fdptr->fd, &cupsd_current_output))
(*(fdptr->write_cb))(fdptr->data);
release_fd(fdptr);
}
}
#endif /* HAVE_KQUEUE */
#if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
/*
* Release all inactive file descriptors...
*/
# ifndef HAVE_KQUEUE
release_inactive:
# endif /* !HAVE_KQUEUE */
cupsd_in_select = 0;
for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_inactive_fds);
fdptr;
fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_inactive_fds))
{
cupsArrayRemove(cupsd_inactive_fds, fdptr);
release_fd(fdptr);
}
#endif /* HAVE_EPOLL || HAVE_KQUEUE */
/*
* Return the number of file descriptors handled...
*/
return (nfds);
}
#ifdef CUPSD_IS_SELECTING
/*
* 'cupsdIsSelecting()' - Determine whether we are monitoring a file
* descriptor.
*/
int /* O - 1 if selecting, 0 otherwise */
cupsdIsSelecting(int fd) /* I - File descriptor */
{
return (find_fd(fd) != NULL);
}
#endif /* CUPSD_IS_SELECTING */
/*
* 'cupsdRemoveSelect()' - Remove a file descriptor from the list.
*/
void
cupsdRemoveSelect(int fd) /* I - File descriptor */
{
_cupsd_fd_t *fdptr; /* File descriptor record */
#ifdef HAVE_EPOLL
struct epoll_event event; /* Event data */
#elif defined(HAVE_KQUEUE)
struct kevent event; /* Event data */
struct timespec timeout; /* Timeout value */
#elif defined(HAVE_POLL)
/* No variables for poll() */
#endif /* HAVE_EPOLL */
/*
* Range check input...
*/
cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdRemoveSelect(fd=%d)", fd);
if (fd < 0)
return;
/*
* Find the file descriptor...
*/
if ((fdptr = find_fd(fd)) == NULL)
return;
#ifdef HAVE_EPOLL
if (epoll_ctl(cupsd_epoll_fd, EPOLL_CTL_DEL, fd, &event))
{
close(cupsd_epoll_fd);
cupsd_epoll_fd = -1;
cupsd_update_pollfds = 1;
}
#elif defined(HAVE_KQUEUE)
timeout.tv_sec = 0;
timeout.tv_nsec = 0;
if (fdptr->read_cb)
{
EV_SET(&event, fd, EVFILT_READ, EV_DELETE, 0, 0, fdptr);
if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
{
cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
strerror(errno));
goto cleanup;
}
}
if (fdptr->write_cb)
{
EV_SET(&event, fd, EVFILT_WRITE, EV_DELETE, 0, 0, fdptr);
if (kevent(cupsd_kqueue_fd, &event, 1, NULL, 0, &timeout))
{
cupsdLogMessage(CUPSD_LOG_EMERG, "kevent() returned %s",
strerror(errno));
goto cleanup;
}
}
#elif defined(HAVE_POLL)
/*
* Update the pollfds array...
*/
cupsd_update_pollfds = 1;
#else /* select() */
FD_CLR(fd, &cupsd_global_input);
FD_CLR(fd, &cupsd_global_output);
FD_CLR(fd, &cupsd_current_input);
FD_CLR(fd, &cupsd_current_output);
#endif /* HAVE_EPOLL */
#ifdef HAVE_KQUEUE
cleanup:
#endif /* HAVE_KQUEUE */
/*
* Remove the file descriptor from the active array and add to the
* inactive array (or release, if we don't need the inactive array...)
*/
cupsArrayRemove(cupsd_fds, fdptr);
#if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
if (cupsd_in_select)
cupsArrayAdd(cupsd_inactive_fds, fdptr);
else
#endif /* HAVE_EPOLL || HAVE_KQUEUE */
release_fd(fdptr);
}
/*
* 'cupsdStartSelect()' - Initialize the file polling engine.
*/
void
cupsdStartSelect(void)
{
cupsdLogMessage(CUPSD_LOG_DEBUG, "cupsdStartSelect()");
cupsd_fds = cupsArrayNew((cups_array_func_t)compare_fds, NULL);
#if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
cupsd_inactive_fds = cupsArrayNew((cups_array_func_t)compare_fds, NULL);
#endif /* HAVE_EPOLL || HAVE_KQUEUE */
#ifdef HAVE_EPOLL
cupsd_epoll_fd = epoll_create(MaxFDs);
cupsd_epoll_events = calloc((size_t)MaxFDs, sizeof(struct epoll_event));
cupsd_update_pollfds = 0;
#elif defined(HAVE_KQUEUE)
cupsd_kqueue_fd = kqueue();
cupsd_kqueue_events = calloc((size_t)MaxFDs, sizeof(struct kevent));
#elif defined(HAVE_POLL)
cupsd_update_pollfds = 0;
#else /* select() */
FD_ZERO(&cupsd_global_input);
FD_ZERO(&cupsd_global_output);
#endif /* HAVE_EPOLL */
}
/*
* 'cupsdStopSelect()' - Shutdown the file polling engine.
*/
void
cupsdStopSelect(void)
{
_cupsd_fd_t *fdptr; /* Current file descriptor */
cupsdLogMessage(CUPSD_LOG_DEBUG, "cupsdStopSelect()");
for (fdptr = (_cupsd_fd_t *)cupsArrayFirst(cupsd_fds);
fdptr;
fdptr = (_cupsd_fd_t *)cupsArrayNext(cupsd_fds))
free(fdptr);
cupsArrayDelete(cupsd_fds);
cupsd_fds = NULL;
#if defined(HAVE_EPOLL) || defined(HAVE_KQUEUE)
cupsArrayDelete(cupsd_inactive_fds);
cupsd_inactive_fds = NULL;
#endif /* HAVE_EPOLL || HAVE_KQUEUE */
#ifdef HAVE_KQUEUE
if (cupsd_kqueue_events)
{
free(cupsd_kqueue_events);
cupsd_kqueue_events = NULL;
}
if (cupsd_kqueue_fd >= 0)
{
close(cupsd_kqueue_fd);
cupsd_kqueue_fd = -1;
}
#elif defined(HAVE_POLL)
# ifdef HAVE_EPOLL
if (cupsd_epoll_events)
{
free(cupsd_epoll_events);
cupsd_epoll_events = NULL;
}
if (cupsd_epoll_fd >= 0)
{
close(cupsd_epoll_fd);
cupsd_epoll_fd = -1;
}
# endif /* HAVE_EPOLL */
if (cupsd_pollfds)
{
free(cupsd_pollfds);
cupsd_pollfds = NULL;
cupsd_alloc_pollfds = 0;
}
cupsd_update_pollfds = 0;
#else /* select() */
FD_ZERO(&cupsd_global_input);
FD_ZERO(&cupsd_global_output);
#endif /* HAVE_EPOLL */
}
/*
* 'compare_fds()' - Compare file descriptors.
*/
static int /* O - Result of comparison */
compare_fds(_cupsd_fd_t *a, /* I - First file descriptor */
_cupsd_fd_t *b) /* I - Second file descriptor */
{
return (a->fd - b->fd);
}
/*
* 'find_fd()' - Find an existing file descriptor record.
*/
static _cupsd_fd_t * /* O - FD record pointer or NULL */
find_fd(int fd) /* I - File descriptor */
{
_cupsd_fd_t *fdptr, /* Matching record (if any) */
key; /* Search key */
cupsArraySave(cupsd_fds);
key.fd = fd;
fdptr = (_cupsd_fd_t *)cupsArrayFind(cupsd_fds, &key);
cupsArrayRestore(cupsd_fds);
return (fdptr);
}
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