74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
/* kqueue interface, C mini-library
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*
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* Copyright 2012 Joey Hess <id@joeyh.name>
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*
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* License: BSD-2-clause
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*/
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#include <stdio.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/event.h>
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#include <sys/time.h>
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#include <errno.h>
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/* The specified fds are added to the set of fds being watched for changes.
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* Fds passed to prior calls still take effect, so it's most efficient to
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* not pass the same fds repeatedly.
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*
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* Returns the fd that changed, or -1 on error.
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*/
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signed int helper(const int kq, const int fdcnt, const int *fdlist, int nodelay) {
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int i, nev;
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struct kevent evlist[1];
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struct kevent chlist[fdcnt];
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struct timespec avoiddelay = {0, 0};
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struct timespec *timeout = nodelay ? &avoiddelay : NULL;
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for (i = 0; i < fdcnt; i++) {
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EV_SET(&chlist[i], fdlist[i], EVFILT_VNODE,
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EV_ADD | EV_ENABLE | EV_CLEAR,
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NOTE_WRITE,
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0, 0);
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}
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nev = kevent(kq, chlist, fdcnt, evlist, 1, timeout);
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if (nev == 1)
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return evlist[0].ident;
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else
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return -1;
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}
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/* Initializes a new, empty kqueue. */
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int init_kqueue() {
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int kq;
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if ((kq = kqueue()) == -1) {
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perror("kqueue");
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exit(1);
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}
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return kq;
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}
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/* Adds fds to the set that should be watched. */
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void addfds_kqueue(const int kq, const int fdcnt, const int *fdlist) {
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helper(kq, fdcnt, fdlist, 1);
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}
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/* Waits for a change event on a kqueue. */
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signed int waitchange_kqueue(const int kq) {
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return helper(kq, 0, NULL, 0);
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}
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/*
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main () {
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int list[1];
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int kq;
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list[0]=open(".", O_RDONLY);
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kq = init_kqueue();
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addfds_kqueue(kq, 1, list)
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printf("change: %i\n", waitchange_kqueue(kq));
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}
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*/
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