glib/gio/inotify/inotify-kernel.c

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/*
Copyright (C) 2005 John McCutchan
The Gnome Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The Gnome Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the Gnome Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
Authors:.
John McCutchan <john@johnmccutchan.com>
*/
#include "config.h"
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <glib.h>
#include "inotify-kernel.h"
#include <sys/inotify.h>
/* Timings for pairing MOVED_TO / MOVED_FROM events */
2010-08-13 23:22:28 +02:00
#define PROCESS_EVENTS_TIME 1000 /* 1000 milliseconds (1 hz) */
#define DEFAULT_HOLD_UNTIL_TIME 0 /* 0 millisecond */
#define MOVE_HOLD_UNTIL_TIME 500 /* 500 microseconds or 0.5 milliseconds */
static int inotify_instance_fd = -1;
static GQueue *events_to_process = NULL;
static GQueue *event_queue = NULL;
static GHashTable * cookie_hash = NULL;
static GIOChannel *inotify_read_ioc;
static GPollFD ik_poll_fd;
static gboolean ik_poll_fd_enabled = TRUE;
static void (*user_cb)(ik_event_t *event);
static gboolean ik_read_callback (gpointer user_data);
static gboolean ik_process_eq_callback (gpointer user_data);
static guint32 ik_move_matches = 0;
static guint32 ik_move_misses = 0;
static gboolean process_eq_running = FALSE;
/* We use the lock from inotify-helper.c
*
* There are two places that we take this lock
*
* 1) In ik_read_callback
*
* 2) ik_process_eq_callback.
*
*
* The rest of locking is taken care of in inotify-helper.c
*/
G_LOCK_EXTERN (inotify_lock);
typedef struct ik_event_internal {
ik_event_t *event;
gboolean seen;
gboolean sent;
GTimeVal hold_until;
struct ik_event_internal *pair;
} ik_event_internal_t;
/* In order to perform non-sleeping inotify event chunking we need
* a custom GSource
*/
static gboolean
ik_source_prepare (GSource *source,
gint *timeout)
{
return FALSE;
}
static gboolean
ik_source_timeout (gpointer data)
{
GSource *source = (GSource *)data;
/* Re-active the PollFD */
g_source_add_poll (source, &ik_poll_fd);
g_source_unref (source);
ik_poll_fd_enabled = TRUE;
return FALSE;
}
#define MAX_PENDING_COUNT 2
#define PENDING_THRESHOLD(qsize) ((qsize) >> 1)
#define PENDING_MARGINAL_COST(p) ((unsigned int)(1 << (p)))
#define MAX_QUEUED_EVENTS 2048
#define AVERAGE_EVENT_SIZE sizeof (struct inotify_event) + 16
#define TIMEOUT_MILLISECONDS 10
static gboolean
ik_source_check (GSource *source)
{
static int prev_pending = 0, pending_count = 0;
/* We already disabled the PollFD or
* nothing to be read from inotify */
if (!ik_poll_fd_enabled || !(ik_poll_fd.revents & G_IO_IN))
return FALSE;
if (pending_count < MAX_PENDING_COUNT)
{
unsigned int pending;
if (ioctl (inotify_instance_fd, FIONREAD, &pending) == -1)
goto do_read;
pending /= AVERAGE_EVENT_SIZE;
/* Don't wait if the number of pending events is too close
* to the maximum queue size.
*/
if (pending > PENDING_THRESHOLD (MAX_QUEUED_EVENTS))
goto do_read;
/* With each successive iteration, the minimum rate for
* further sleep doubles.
*/
if (pending-prev_pending < PENDING_MARGINAL_COST (pending_count))
goto do_read;
prev_pending = pending;
pending_count++;
/* We are going to wait to read the events: */
/* Remove the PollFD from the source */
g_source_remove_poll (source, &ik_poll_fd);
/* To avoid threading issues we need to flag that we've done that */
ik_poll_fd_enabled = FALSE;
/* Set a timeout to re-add the PollFD to the source */
g_source_ref (source);
g_timeout_add (TIMEOUT_MILLISECONDS, ik_source_timeout, source);
return FALSE;
}
do_read:
/* We are ready to read events from inotify */
prev_pending = 0;
pending_count = 0;
return TRUE;
}
static gboolean
ik_source_dispatch (GSource *source,
GSourceFunc callback,
gpointer user_data)
{
if (callback)
return callback (user_data);
return TRUE;
}
static GSourceFuncs ik_source_funcs =
{
ik_source_prepare,
ik_source_check,
ik_source_dispatch,
NULL
};
gboolean _ik_startup (void (*cb)(ik_event_t *event))
{
static gboolean initialized = FALSE;
GSource *source;
user_cb = cb;
/* Ignore multi-calls */
if (initialized)
return inotify_instance_fd >= 0;
initialized = TRUE;
#ifdef HAVE_INOTIFY_INIT1
inotify_instance_fd = inotify_init1 (IN_CLOEXEC);
#else
inotify_instance_fd = -1;
#endif
if (inotify_instance_fd < 0)
inotify_instance_fd = inotify_init ();
if (inotify_instance_fd < 0)
return FALSE;
inotify_read_ioc = g_io_channel_unix_new (inotify_instance_fd);
ik_poll_fd.fd = inotify_instance_fd;
ik_poll_fd.events = G_IO_IN | G_IO_HUP | G_IO_ERR;
g_io_channel_set_encoding (inotify_read_ioc, NULL, NULL);
g_io_channel_set_flags (inotify_read_ioc, G_IO_FLAG_NONBLOCK, NULL);
source = g_source_new (&ik_source_funcs, sizeof (GSource));
g_source_set_name (source, "GIO Inotify");
g_source_add_poll (source, &ik_poll_fd);
g_source_set_callback (source, ik_read_callback, NULL, NULL);
g_source_attach (source, NULL);
g_source_unref (source);
cookie_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
event_queue = g_queue_new ();
events_to_process = g_queue_new ();
return TRUE;
}
static ik_event_internal_t *
ik_event_internal_new (ik_event_t *event)
{
ik_event_internal_t *internal_event = g_new0 (ik_event_internal_t, 1);
GTimeVal tv;
g_assert (event);
g_get_current_time (&tv);
g_time_val_add (&tv, DEFAULT_HOLD_UNTIL_TIME);
internal_event->event = event;
internal_event->hold_until = tv;
return internal_event;
}
static ik_event_t *
ik_event_new (char *buffer)
{
struct inotify_event *kevent = (struct inotify_event *)buffer;
ik_event_t *event = g_new0 (ik_event_t, 1);
g_assert (buffer);
event->wd = kevent->wd;
event->mask = kevent->mask;
event->cookie = kevent->cookie;
event->len = kevent->len;
if (event->len)
event->name = g_strdup (kevent->name);
else
event->name = g_strdup ("");
return event;
}
ik_event_t *
_ik_event_new_dummy (const char *name,
gint32 wd,
guint32 mask)
{
ik_event_t *event = g_new0 (ik_event_t, 1);
event->wd = wd;
event->mask = mask;
event->cookie = 0;
if (name)
event->name = g_strdup (name);
else
event->name = g_strdup("");
event->len = strlen (event->name);
return event;
}
void
_ik_event_free (ik_event_t *event)
{
if (event->pair)
_ik_event_free (event->pair);
g_free (event->name);
g_free (event);
}
gint32
_ik_watch (const char *path,
guint32 mask,
int *err)
{
gint32 wd = -1;
g_assert (path != NULL);
g_assert (inotify_instance_fd >= 0);
wd = inotify_add_watch (inotify_instance_fd, path, mask);
if (wd < 0)
{
int e = errno;
/* FIXME: debug msg failed to add watch */
if (err)
*err = e;
return wd;
}
g_assert (wd >= 0);
return wd;
}
int
_ik_ignore (const char *path,
gint32 wd)
{
g_assert (wd >= 0);
g_assert (inotify_instance_fd >= 0);
if (inotify_rm_watch (inotify_instance_fd, wd) < 0)
{
/* int e = errno; */
/* failed to rm watch */
return -1;
}
return 0;
}
void
_ik_move_stats (guint32 *matches,
guint32 *misses)
{
if (matches)
*matches = ik_move_matches;
if (misses)
*misses = ik_move_misses;
}
const char *
_ik_mask_to_string (guint32 mask)
{
gboolean is_dir = mask & IN_ISDIR;
mask &= ~IN_ISDIR;
if (is_dir)
{
switch (mask)
{
case IN_ACCESS:
return "ACCESS (dir)";
case IN_MODIFY:
return "MODIFY (dir)";
case IN_ATTRIB:
return "ATTRIB (dir)";
case IN_CLOSE_WRITE:
return "CLOSE_WRITE (dir)";
case IN_CLOSE_NOWRITE:
return "CLOSE_NOWRITE (dir)";
case IN_OPEN:
return "OPEN (dir)";
case IN_MOVED_FROM:
return "MOVED_FROM (dir)";
case IN_MOVED_TO:
return "MOVED_TO (dir)";
case IN_DELETE:
return "DELETE (dir)";
case IN_CREATE:
return "CREATE (dir)";
case IN_DELETE_SELF:
return "DELETE_SELF (dir)";
case IN_UNMOUNT:
return "UNMOUNT (dir)";
case IN_Q_OVERFLOW:
return "Q_OVERFLOW (dir)";
case IN_IGNORED:
return "IGNORED (dir)";
default:
return "UNKNOWN_EVENT (dir)";
}
}
else
{
switch (mask)
{
case IN_ACCESS:
return "ACCESS";
case IN_MODIFY:
return "MODIFY";
case IN_ATTRIB:
return "ATTRIB";
case IN_CLOSE_WRITE:
return "CLOSE_WRITE";
case IN_CLOSE_NOWRITE:
return "CLOSE_NOWRITE";
case IN_OPEN:
return "OPEN";
case IN_MOVED_FROM:
return "MOVED_FROM";
case IN_MOVED_TO:
return "MOVED_TO";
case IN_DELETE:
return "DELETE";
case IN_CREATE:
return "CREATE";
case IN_DELETE_SELF:
return "DELETE_SELF";
case IN_UNMOUNT:
return "UNMOUNT";
case IN_Q_OVERFLOW:
return "Q_OVERFLOW";
case IN_IGNORED:
return "IGNORED";
default:
return "UNKNOWN_EVENT";
}
}
}
static void
ik_read_events (gsize *buffer_size_out,
gchar **buffer_out)
{
static gchar *buffer = NULL;
static gsize buffer_size;
/* Initialize the buffer on our first call */
if (buffer == NULL)
{
buffer_size = AVERAGE_EVENT_SIZE;
buffer_size *= MAX_QUEUED_EVENTS;
buffer = g_malloc (buffer_size);
}
*buffer_size_out = 0;
*buffer_out = NULL;
memset (buffer, 0, buffer_size);
if (g_io_channel_read_chars (inotify_read_ioc, (char *)buffer, buffer_size, buffer_size_out, NULL) != G_IO_STATUS_NORMAL) {
/* error reading */
}
*buffer_out = buffer;
}
static gboolean
ik_read_callback (gpointer user_data)
{
gchar *buffer;
gsize buffer_size, buffer_i, events;
G_LOCK (inotify_lock);
ik_read_events (&buffer_size, &buffer);
buffer_i = 0;
events = 0;
while (buffer_i < buffer_size)
{
struct inotify_event *event;
gsize event_size;
event = (struct inotify_event *)&buffer[buffer_i];
event_size = sizeof(struct inotify_event) + event->len;
g_queue_push_tail (events_to_process, ik_event_internal_new (ik_event_new (&buffer[buffer_i])));
buffer_i += event_size;
events++;
}
/* If the event process callback is off, turn it back on */
if (!process_eq_running && events)
{
process_eq_running = TRUE;
g_timeout_add (PROCESS_EVENTS_TIME, ik_process_eq_callback, NULL);
}
G_UNLOCK (inotify_lock);
return TRUE;
}
static gboolean
g_timeval_lt (GTimeVal *val1,
GTimeVal *val2)
{
if (val1->tv_sec < val2->tv_sec)
return TRUE;
if (val1->tv_sec > val2->tv_sec)
return FALSE;
/* val1->tv_sec == val2->tv_sec */
if (val1->tv_usec < val2->tv_usec)
return TRUE;
return FALSE;
}
static gboolean
g_timeval_eq (GTimeVal *val1,
GTimeVal *val2)
{
return (val1->tv_sec == val2->tv_sec) && (val1->tv_usec == val2->tv_usec);
}
static void
ik_pair_events (ik_event_internal_t *event1,
ik_event_internal_t *event2)
{
g_assert (event1 && event2);
/* We should only be pairing events that have the same cookie */
g_assert (event1->event->cookie == event2->event->cookie);
/* We shouldn't pair an event that already is paired */
g_assert (event1->pair == NULL && event2->pair == NULL);
/* Pair the internal structures and the ik_event_t structures */
event1->pair = event2;
event1->event->pair = event2->event;
event2->event->is_second_in_pair = TRUE;
if (g_timeval_lt (&event1->hold_until, &event2->hold_until))
event1->hold_until = event2->hold_until;
event2->hold_until = event1->hold_until;
}
static void
ik_event_add_microseconds (ik_event_internal_t *event,
glong ms)
{
g_assert (event);
g_time_val_add (&event->hold_until, ms);
}
static gboolean
ik_event_ready (ik_event_internal_t *event)
{
GTimeVal tv;
g_assert (event);
g_get_current_time (&tv);
/* An event is ready if,
*
* it has no cookie -- there is nothing to be gained by holding it
* or, it is already paired -- we don't need to hold it anymore
* or, we have held it long enough
*/
return
event->event->cookie == 0 ||
event->pair != NULL ||
g_timeval_lt (&event->hold_until, &tv) ||
g_timeval_eq (&event->hold_until, &tv);
}
static void
ik_pair_moves (gpointer data,
gpointer user_data)
{
ik_event_internal_t *event = (ik_event_internal_t *)data;
if (event->seen == TRUE || event->sent == TRUE)
return;
if (event->event->cookie != 0)
{
/* When we get a MOVED_FROM event we delay sending the event by
* MOVE_HOLD_UNTIL_TIME microseconds. We need to do this because a
* MOVED_TO pair _might_ be coming in the near future */
if (event->event->mask & IN_MOVED_FROM)
{
g_hash_table_insert (cookie_hash, GINT_TO_POINTER (event->event->cookie), event);
/* because we don't deliver move events there is no point in waiting for the match right now. */
ik_event_add_microseconds (event, MOVE_HOLD_UNTIL_TIME);
}
else if (event->event->mask & IN_MOVED_TO)
{
/* We need to check if we are waiting for this MOVED_TO events cookie to pair it with
* a MOVED_FROM */
ik_event_internal_t *match = NULL;
match = g_hash_table_lookup (cookie_hash, GINT_TO_POINTER (event->event->cookie));
if (match)
{
g_hash_table_remove (cookie_hash, GINT_TO_POINTER (event->event->cookie));
ik_pair_events (match, event);
}
}
}
event->seen = TRUE;
}
static void
ik_process_events (void)
{
g_queue_foreach (events_to_process, ik_pair_moves, NULL);
while (!g_queue_is_empty (events_to_process))
{
ik_event_internal_t *event = g_queue_peek_head (events_to_process);
/* This must have been sent as part of a MOVED_TO/MOVED_FROM */
if (event->sent)
{
/* Pop event */
g_queue_pop_head (events_to_process);
/* Free the internal event structure */
g_free (event);
continue;
}
/* The event isn't ready yet */
if (!ik_event_ready (event))
break;
/* Pop it */
event = g_queue_pop_head (events_to_process);
/* Check if this is a MOVED_FROM that is also sitting in the cookie_hash */
if (event->event->cookie && event->pair == NULL &&
g_hash_table_lookup (cookie_hash, GINT_TO_POINTER (event->event->cookie)))
g_hash_table_remove (cookie_hash, GINT_TO_POINTER (event->event->cookie));
if (event->pair)
{
/* We send out paired MOVED_FROM/MOVED_TO events in the same event buffer */
/* g_assert (event->event->mask == IN_MOVED_FROM && event->pair->event->mask == IN_MOVED_TO); */
/* Copy the paired data */
event->pair->sent = TRUE;
event->sent = TRUE;
ik_move_matches++;
}
else if (event->event->cookie)
{
/* If we couldn't pair a MOVED_FROM and MOVED_TO together, we change
* the event masks */
/* Changeing MOVED_FROM to DELETE and MOVED_TO to create lets us make
* the gaurantee that you will never see a non-matched MOVE event */
event->event->original_mask = event->event->mask;
if (event->event->mask & IN_MOVED_FROM)
{
event->event->mask = IN_DELETE|(event->event->mask & IN_ISDIR);
ik_move_misses++; /* not super accurate, if we aren't watching the destination it still counts as a miss */
}
if (event->event->mask & IN_MOVED_TO)
event->event->mask = IN_CREATE|(event->event->mask & IN_ISDIR);
}
/* Push the ik_event_t onto the event queue */
g_queue_push_tail (event_queue, event->event);
/* Free the internal event structure */
g_free (event);
}
}
static gboolean
ik_process_eq_callback (gpointer user_data)
{
gboolean res;
/* Try and move as many events to the event queue */
G_LOCK (inotify_lock);
ik_process_events ();
while (!g_queue_is_empty (event_queue))
{
ik_event_t *event = g_queue_pop_head (event_queue);
user_cb (event);
}
res = TRUE;
if (g_queue_get_length (events_to_process) == 0)
{
process_eq_running = FALSE;
res = FALSE;
}
G_UNLOCK (inotify_lock);
return res;
}