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40cec27636
Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Jeremy Allison <jra@samba.org>
458 lines
11 KiB
C
458 lines
11 KiB
C
/*
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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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*/
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/*
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notify implementation using inotify
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*/
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#include "includes.h"
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#include "../librpc/gen_ndr/notify.h"
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#include "smbd/smbd.h"
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#include "lib/util/sys_rw_data.h"
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#include <sys/inotify.h>
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/* glibc < 2.5 headers don't have these defines */
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#ifndef IN_ONLYDIR
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#define IN_ONLYDIR 0x01000000
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#endif
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#ifndef IN_MASK_ADD
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#define IN_MASK_ADD 0x20000000
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#endif
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struct inotify_private {
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struct sys_notify_context *ctx;
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int fd;
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struct inotify_watch_context *watches;
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};
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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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int wd;
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void (*callback)(struct sys_notify_context *ctx,
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void *private_data,
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struct notify_event *ev,
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uint32_t filter);
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void *private_data;
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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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const char *path;
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};
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/*
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map from a change notify mask to a inotify mask. Remove any bits
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which we can handle
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*/
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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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};
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static uint32_t inotify_map(uint32_t *filter)
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{
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size_t i;
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uint32_t out=0;
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for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
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if (inotify_mapping[i].notify_mask & *filter) {
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out |= inotify_mapping[i].inotify_mask;
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*filter &= ~inotify_mapping[i].notify_mask;
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}
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}
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return out;
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}
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/*
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* Map inotify mask back to filter. This returns all filters that
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* could have created the inotify watch.
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*/
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static uint32_t inotify_map_mask_to_filter(uint32_t mask)
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{
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size_t i;
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uint32_t filter = 0;
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for (i = 0; i < ARRAY_SIZE(inotify_mapping); i++) {
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if (inotify_mapping[i].inotify_mask & mask) {
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filter |= inotify_mapping[i].notify_mask;
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}
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}
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if (mask & IN_ISDIR) {
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filter &= ~FILE_NOTIFY_CHANGE_FILE_NAME;
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} else {
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filter &= ~FILE_NOTIFY_CHANGE_DIR_NAME;
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}
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return filter;
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}
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/*
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destroy the inotify private context
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*/
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static int inotify_destructor(struct inotify_private *in)
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{
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close(in->fd);
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return 0;
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}
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/*
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see if a particular event from inotify really does match a requested
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notify event in SMB
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*/
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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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{
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bool ok;
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DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n",
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e->mask, w->mask, w->filter));
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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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return False;
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}
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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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ok = ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) != 0);
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return ok;
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}
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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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return True;
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}
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if ((e->mask & IN_MODIFY) &&
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(w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
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return True;
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}
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ok = ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) != 0);
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return ok;
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}
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/*
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dispatch one inotify event
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the cookies are used to correctly handle renames
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*/
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static void inotify_dispatch(struct inotify_private *in,
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struct inotify_event *e,
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int prev_wd,
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uint32_t prev_cookie,
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struct inotify_event *e2)
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{
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struct inotify_watch_context *w, *next;
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struct notify_event ne;
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uint32_t filter;
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DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n",
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e->mask, e->len ? e->name : ""));
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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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return;
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}
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/* map the inotify mask to a action. This gets complicated for
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renames */
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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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e2->wd == e->wd) {
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ne.action = NOTIFY_ACTION_OLD_NAME;
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} else {
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ne.action = NOTIFY_ACTION_REMOVED;
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}
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} else if (e->mask & IN_MOVED_TO) {
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if ((e->cookie == prev_cookie) && (e->wd == prev_wd)) {
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ne.action = NOTIFY_ACTION_NEW_NAME;
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} else {
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ne.action = NOTIFY_ACTION_ADDED;
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}
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} else {
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ne.action = NOTIFY_ACTION_MODIFIED;
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}
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ne.path = e->name;
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filter = inotify_map_mask_to_filter(e->mask);
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DBG_DEBUG("ne.action = %d, ne.path = %s, filter = %d\n",
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ne.action, ne.path, filter);
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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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next = w->next;
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if (w->wd == e->wd && filter_match(w, e)) {
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ne.dir = w->path;
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w->callback(in->ctx, w->private_data, &ne, filter);
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}
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}
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if ((ne.action == NOTIFY_ACTION_NEW_NAME) &&
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((e->mask & IN_ISDIR) == 0)) {
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/*
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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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*/
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ne.action = NOTIFY_ACTION_MODIFIED;
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e->mask = IN_ATTRIB;
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for (w=in->watches;w;w=next) {
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next = 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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ne.dir = w->path;
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w->callback(in->ctx, w->private_data, &ne,
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filter);
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}
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}
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}
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}
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/*
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called when the kernel has some events for us
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*/
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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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{
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struct inotify_private *in = talloc_get_type(private_data,
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struct inotify_private);
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int bufsize = 0;
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struct inotify_event *e0, *e;
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uint32_t prev_cookie=0;
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int prev_wd = -1;
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ssize_t ret;
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/*
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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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otherwise
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*/
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if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
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bufsize == 0) {
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DEBUG(0,("No data on inotify fd?!\n"));
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TALLOC_FREE(fde);
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return;
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}
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e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize + 1);
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if (e == NULL) return;
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((uint8_t *)e)[bufsize] = '\0';
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ret = read_data(in->fd, e0, bufsize);
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if (ret != bufsize) {
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DEBUG(0, ("Failed to read all inotify data - %s\n",
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strerror(errno)));
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talloc_free(e0);
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/* the inotify fd will now be out of sync,
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* can't keep reading data off it */
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TALLOC_FREE(fde);
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return;
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}
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/* we can get more than one event in the buffer */
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while (e && (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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}
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inotify_dispatch(in, e, prev_wd, prev_cookie, e2);
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prev_wd = e->wd;
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prev_cookie = e->cookie;
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e = e2;
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}
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talloc_free(e0);
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}
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/*
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setup the inotify handle - called the first time a watch is added on
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this context
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*/
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static int inotify_setup(struct sys_notify_context *ctx)
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{
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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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if (in == NULL) {
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return ENOMEM;
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}
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in->fd = inotify_init();
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if (in->fd == -1) {
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int ret = errno;
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DEBUG(0, ("Failed to init inotify - %s\n", strerror(ret)));
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talloc_free(in);
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return ret;
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}
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in->ctx = ctx;
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in->watches = NULL;
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ctx->private_data = in;
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talloc_set_destructor(in, inotify_destructor);
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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, TEVENT_FD_READ,
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inotify_handler, in);
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if (fde == NULL) {
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ctx->private_data = NULL;
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TALLOC_FREE(in);
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return ENOMEM;
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}
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return 0;
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}
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/*
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destroy a watch
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*/
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static int watch_destructor(struct inotify_watch_context *w)
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{
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struct inotify_private *in = w->in;
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int wd = w->wd;
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DLIST_REMOVE(w->in->watches, w);
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for (w=in->watches;w;w=w->next) {
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if (w->wd == wd) {
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/*
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* Another inotify_watch_context listens on this path,
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* leave the kernel level watch in place
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*/
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return 0;
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}
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}
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DEBUG(10, ("Deleting inotify watch %d\n", wd));
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if (inotify_rm_watch(in->fd, wd) == -1) {
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DEBUG(1, ("inotify_rm_watch returned %s\n", strerror(errno)));
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}
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return 0;
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}
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/*
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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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*/
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int inotify_watch(TALLOC_CTX *mem_ctx,
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struct sys_notify_context *ctx,
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const char *path,
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uint32_t *filter,
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uint32_t *subdir_filter,
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void (*callback)(struct sys_notify_context *ctx,
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void *private_data,
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struct notify_event *ev,
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uint32_t filter),
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void *private_data,
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void *handle_p)
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{
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struct inotify_private *in;
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uint32_t mask;
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struct inotify_watch_context *w;
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uint32_t orig_filter = *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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int ret;
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ret = inotify_setup(ctx);
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if (ret != 0) {
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return ret;
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}
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}
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in = talloc_get_type(ctx->private_data, struct inotify_private);
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mask = inotify_map(filter);
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if (mask == 0) {
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/* this filter can't be handled by inotify */
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return EINVAL;
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}
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/* using IN_MASK_ADD allows us to cope with inotify() returning the same
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watch descriptor for multiple watches on the same path */
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mask |= (IN_MASK_ADD | IN_ONLYDIR);
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w = talloc(mem_ctx, struct inotify_watch_context);
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if (w == NULL) {
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*filter = orig_filter;
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return ENOMEM;
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}
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w->in = in;
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w->callback = callback;
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w->private_data = private_data;
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w->mask = mask;
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w->filter = orig_filter;
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w->path = talloc_strdup(w, path);
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if (w->path == NULL) {
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*filter = orig_filter;
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TALLOC_FREE(w);
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return ENOMEM;
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}
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/* get a new watch descriptor for this path */
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w->wd = inotify_add_watch(in->fd, path, mask);
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if (w->wd == -1) {
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int err = errno;
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*filter = orig_filter;
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TALLOC_FREE(w);
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DEBUG(1, ("inotify_add_watch returned %s\n", strerror(err)));
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return err;
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}
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DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n",
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path, mask, w->wd));
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(*handle) = w;
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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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return 0;
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}
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