transmission/libtransmission/watchdir-kqueue.c

170 lines
4.0 KiB
C

/*
* This file Copyright (C) 2015-2016 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#include <assert.h>
#include <errno.h>
#include <string.h> /* strcmp () */
#include <fcntl.h> /* open () */
#include <unistd.h> /* close () */
#include <sys/types.h>
#include <sys/event.h>
#ifndef O_EVTONLY
#define O_EVTONLY O_RDONLY
#endif
#include <event2/event.h>
#define __LIBTRANSMISSION_WATCHDIR_MODULE__
#include "transmission.h"
#include "log.h"
#include "ptrarray.h"
#include "utils.h"
#include "watchdir.h"
#include "watchdir-common.h"
/***
****
***/
#define log_error(...) (!tr_logLevelIsActive (TR_LOG_ERROR) ? (void) 0 : \
tr_logAddMessage (__FILE__, __LINE__, TR_LOG_ERROR, "watchdir:kqueue", __VA_ARGS__))
/***
****
***/
typedef struct tr_watchdir_kqueue
{
tr_watchdir_backend base;
int kq;
int dirfd;
struct event * event;
tr_ptrArray dir_entries;
}
tr_watchdir_kqueue;
#define BACKEND_UPCAST(b) ((tr_watchdir_kqueue *) (b))
#define KQUEUE_WATCH_MASK (NOTE_WRITE | NOTE_EXTEND)
/***
****
***/
static void
tr_watchdir_kqueue_on_event (evutil_socket_t fd UNUSED,
short type UNUSED,
void * context)
{
const tr_watchdir_t handle = context;
tr_watchdir_kqueue * const backend = BACKEND_UPCAST (tr_watchdir_get_backend (handle));
struct kevent ke;
const struct timespec ts = { 0, 0 };
if (kevent (backend->kq, NULL, 0, &ke, 1, &ts) == -1)
{
log_error ("Failed to fetch kevent: %s", tr_strerror (errno));
return;
}
/* Read directory with generic scan */
tr_watchdir_scan (handle, &backend->dir_entries);
}
static void
tr_watchdir_kqueue_free (tr_watchdir_backend * backend_base)
{
tr_watchdir_kqueue * const backend = BACKEND_UPCAST (backend_base);
if (backend == NULL)
return;
assert (backend->base.free_func == &tr_watchdir_kqueue_free);
if (backend->event != NULL)
{
event_del (backend->event);
event_free (backend->event);
}
if (backend->kq != -1)
close (backend->kq);
if (backend->dirfd != -1)
close (backend->dirfd);
tr_ptrArrayDestruct (&backend->dir_entries, &tr_free);
tr_free (backend);
}
tr_watchdir_backend *
tr_watchdir_kqueue_new (tr_watchdir_t handle)
{
const char * const path = tr_watchdir_get_path (handle);
struct kevent ke;
tr_watchdir_kqueue * backend;
backend = tr_new0 (tr_watchdir_kqueue, 1);
backend->base.free_func = &tr_watchdir_kqueue_free;
backend->kq = -1;
backend->dirfd = -1;
if ((backend->kq = kqueue ()) == -1)
{
log_error ("Failed to start kqueue");
goto fail;
}
/* Open fd for watching */
if ((backend->dirfd = open (path, O_RDONLY | O_EVTONLY)) == -1)
{
log_error ("Failed to passively watch directory \"%s\": %s", path,
tr_strerror (errno));
goto fail;
}
/* Register kevent filter with kqueue descriptor */
EV_SET (&ke, backend->dirfd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
KQUEUE_WATCH_MASK, 0, NULL);
if (kevent (backend->kq, &ke, 1, NULL, 0, NULL) == -1)
{
log_error ("Failed to set directory event filter with fd %d: %s", backend->kq,
tr_strerror (errno));
goto fail;
}
/* Create libevent task for event descriptor */
if ((backend->event = event_new (tr_watchdir_get_event_base (handle), backend->kq,
EV_READ | EV_ET | EV_PERSIST,
&tr_watchdir_kqueue_on_event, handle)) == NULL)
{
log_error ("Failed to create event: %s", tr_strerror (errno));
goto fail;
}
if (event_add (backend->event, NULL) == -1)
{
log_error ("Failed to add event: %s", tr_strerror (errno));
goto fail;
}
/* Trigger one event for the initial scan */
event_active (backend->event, EV_READ, 0);
return BACKEND_DOWNCAST (backend);
fail:
tr_watchdir_kqueue_free (BACKEND_DOWNCAST (backend));
return NULL;
}