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Unix SMB/CIFS implementation.
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Copyright (C) Andrew Tridgell 2006
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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notify implementation using inotify
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#include "system/filesys.h"
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#include "ntvfs/sysdep/sys_notify.h"
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#include "../lib/util/dlinklist.h"
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#include "libcli/raw/smb.h"
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#include "param/param.h"
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#if HAVE_SYS_INOTIFY_H
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#include <sys/inotify.h>
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/* for older glibc varients - we can remove this eventually */
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#include <linux/inotify.h>
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#include <asm/unistd.h>
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#ifndef HAVE_INOTIFY_INIT
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glibc doesn't define these functions yet (as of March 2006)
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static int inotify_init(void)
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return syscall(__NR_inotify_init);
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static int inotify_add_watch(int fd, const char *path, __u32 mask)
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return syscall(__NR_inotify_add_watch, fd, path, mask);
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static int inotify_rm_watch(int fd, int wd)
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return syscall(__NR_inotify_rm_watch, fd, wd);
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/* older glibc headers don't have these defines either */
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#define IN_ONLYDIR 0x01000000
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#define IN_MASK_ADD 0x20000000
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struct inotify_private {
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struct sys_notify_context *ctx;
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struct inotify_watch_context *watches;
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struct inotify_watch_context {
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struct inotify_watch_context *next, *prev;
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struct inotify_private *in;
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sys_notify_callback_t callback;
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uint32_t mask; /* the inotify mask */
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uint32_t filter; /* the windows completion filter */
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see if a particular event from inotify really does match a requested
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static bool filter_match(struct inotify_watch_context *w,
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struct inotify_event *e)
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if ((e->mask & w->mask) == 0) {
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/* this happens because inotify_add_watch() coalesces watches on the same
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path, oring their masks together */
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/* SMB separates the filters for files and directories */
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if (e->mask & IN_ISDIR) {
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if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
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if ((e->mask & IN_ATTRIB) &&
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(w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
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FILE_NOTIFY_CHANGE_LAST_WRITE|
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FILE_NOTIFY_CHANGE_LAST_ACCESS|
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FILE_NOTIFY_CHANGE_EA|
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FILE_NOTIFY_CHANGE_SECURITY))) {
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if ((e->mask & IN_MODIFY) &&
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(w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
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if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
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dispatch one inotify event
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the cookies are used to correctly handle renames
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static void inotify_dispatch(struct inotify_private *in,
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struct inotify_event *e,
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uint32_t prev_cookie,
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struct inotify_event *e2)
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struct inotify_watch_context *w, *next;
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struct notify_event ne;
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/* ignore extraneous events, such as unmount and IN_IGNORED events */
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if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
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IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
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/* map the inotify mask to a action. This gets complicated for
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if (e->mask & IN_CREATE) {
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ne.action = NOTIFY_ACTION_ADDED;
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} else if (e->mask & IN_DELETE) {
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ne.action = NOTIFY_ACTION_REMOVED;
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} else if (e->mask & IN_MOVED_FROM) {
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if (e2 != NULL && e2->cookie == e->cookie) {
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ne.action = NOTIFY_ACTION_OLD_NAME;
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ne.action = NOTIFY_ACTION_REMOVED;
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} else if (e->mask & IN_MOVED_TO) {
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if (e->cookie == prev_cookie) {
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ne.action = NOTIFY_ACTION_NEW_NAME;
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ne.action = NOTIFY_ACTION_ADDED;
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ne.action = NOTIFY_ACTION_MODIFIED;
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/* find any watches that have this watch descriptor */
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for (w=in->watches;w;w=next) {
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if (w->wd == e->wd && filter_match(w, e)) {
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w->callback(in->ctx, w->private_data, &ne);
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/* SMB expects a file rename to generate three events, two for
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the rename and the other for a modify of the
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destination. Strange! */
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if (ne.action != NOTIFY_ACTION_NEW_NAME ||
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(e->mask & IN_ISDIR) != 0) {
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ne.action = NOTIFY_ACTION_MODIFIED;
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for (w=in->watches;w;w=next) {
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if (w->wd == e->wd && filter_match(w, e) &&
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!(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
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w->callback(in->ctx, w->private_data, &ne);
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called when the kernel has some events for us
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static void inotify_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data)
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struct inotify_private *in = talloc_get_type(private_data,
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struct inotify_private);
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struct inotify_event *e0, *e;
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uint32_t prev_cookie=0;
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we must use FIONREAD as we cannot predict the length of the
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filenames, and thus can't know how much to allocate
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if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
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DEBUG(0,("No data on inotify fd?!\n"));
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e0 = e = talloc_size(in, bufsize);
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if (e == NULL) return;
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if (read(in->fd, e0, bufsize) != bufsize) {
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DEBUG(0,("Failed to read all inotify data\n"));
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/* we can get more than one event in the buffer */
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while (bufsize >= sizeof(*e)) {
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struct inotify_event *e2 = NULL;
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bufsize -= e->len + sizeof(*e);
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if (bufsize >= sizeof(*e)) {
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e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
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inotify_dispatch(in, e, prev_cookie, e2);
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prev_cookie = e->cookie;
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setup the inotify handle - called the first time a watch is added on
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static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
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struct inotify_private *in;
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struct tevent_fd *fde;
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in = talloc(ctx, struct inotify_private);
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NT_STATUS_HAVE_NO_MEMORY(in);
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in->fd = inotify_init();
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DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
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return map_nt_error_from_unix(errno);
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ctx->private_data = in;
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/* add a event waiting for the inotify fd to be readable */
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fde = tevent_add_fd(ctx->ev, in, in->fd,
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TEVENT_FD_READ, inotify_handler, in);
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DEBUG(0,("Failed to tevent_add_fd() - %s\n", strerror(errno)));
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return map_nt_error_from_unix(errno);
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tevent_fd_set_auto_close(fde);
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map from a change notify mask to a inotify mask. Remove any bits
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static const struct {
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uint32_t notify_mask;
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uint32_t inotify_mask;
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} inotify_mapping[] = {
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{FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
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{FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
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{FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
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{FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
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{FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
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{FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
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{FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
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static uint32_t inotify_map(struct notify_entry *e)
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for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
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if (inotify_mapping[i].notify_mask & e->filter) {
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out |= inotify_mapping[i].inotify_mask;
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e->filter &= ~inotify_mapping[i].notify_mask;
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static int watch_destructor(struct inotify_watch_context *w)
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struct inotify_private *in = w->in;
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DLIST_REMOVE(w->in->watches, w);
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/* only rm the watch if its the last one with this wd */
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for (w=in->watches;w;w=w->next) {
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if (w->wd == wd) break;
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inotify_rm_watch(in->fd, wd);
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add a watch. The watch is removed when the caller calls
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talloc_free() on *handle
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static NTSTATUS inotify_watch(struct sys_notify_context *ctx,
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struct notify_entry *e,
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sys_notify_callback_t callback,
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struct inotify_private *in;
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struct inotify_watch_context *w;
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uint32_t filter = e->filter;
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void **handle = (void **)handle_p;
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/* maybe setup the inotify fd */
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if (ctx->private_data == NULL) {
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status = inotify_setup(ctx);
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NT_STATUS_NOT_OK_RETURN(status);
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in = talloc_get_type(ctx->private_data, struct inotify_private);
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mask = inotify_map(e);
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/* this filter can't be handled by inotify */
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return NT_STATUS_INVALID_PARAMETER;
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/* using IN_MASK_ADD allows us to cope with inotify() returning the same
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watch descriptor for muliple watches on the same path */
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mask |= (IN_MASK_ADD | IN_ONLYDIR);
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/* get a new watch descriptor for this path */
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wd = inotify_add_watch(in->fd, e->path, mask);
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return map_nt_error_from_unix(errno);
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w = talloc(in, struct inotify_watch_context);
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inotify_rm_watch(in->fd, wd);
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return NT_STATUS_NO_MEMORY;
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w->callback = callback;
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w->private_data = private_data;
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w->path = talloc_strdup(w, e->path);
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if (w->path == NULL) {
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inotify_rm_watch(in->fd, wd);
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return NT_STATUS_NO_MEMORY;
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DLIST_ADD(in->watches, w);
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/* the caller frees the handle to stop watching */
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talloc_set_destructor(w, watch_destructor);
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static struct sys_notify_backend inotify = {
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.notify_watch = inotify_watch
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initialialise the inotify module
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NTSTATUS sys_notify_inotify_init(void)
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/* register ourselves as a system inotify module */
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return sys_notify_register(&inotify);