source: branches/samba-3.0/source/smbd/notify_inotify.c@ 403

/* 
   Unix SMB/CIFS implementation.

   Copyright (C) Andrew Tridgell 2006
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
  notify implementation using inotify
*/

#include "includes.h"

#ifdef HAVE_INOTIFY

#ifdef HAVE_ASM_TYPES_H
#include <asm/types.h>
#endif

#ifndef HAVE_INOTIFY_INIT

#include <linux/inotify.h>
#include <asm/unistd.h>


/*
  glibc doesn't define these functions yet (as of March 2006)
*/
static int inotify_init(void)
{
        return syscall(__NR_inotify_init);
}

static int inotify_add_watch(int fd, const char *path, __u32 mask)
{
        return syscall(__NR_inotify_add_watch, fd, path, mask);
}

static int inotify_rm_watch(int fd, int wd)
{
        return syscall(__NR_inotify_rm_watch, fd, wd);
}
#else

#include <sys/inotify.h>

#endif


/* older glibc headers don't have these defines either */
#ifndef IN_ONLYDIR
#define IN_ONLYDIR 0x01000000
#endif
#ifndef IN_MASK_ADD
#define IN_MASK_ADD 0x20000000
#endif

struct inotify_private {
        struct sys_notify_context *ctx;
        int fd;
        struct inotify_watch_context *watches;
};

struct inotify_watch_context {
        struct inotify_watch_context *next, *prev;
        struct inotify_private *in;
        int wd;
        void (*callback)(struct sys_notify_context *ctx, 
                         void *private_data,
                         struct notify_event *ev);
        void *private_data;
        uint32_t mask; /* the inotify mask */
        uint32_t filter; /* the windows completion filter */
        const char *path;
};


/*
  destroy the inotify private context
*/
static int inotify_destructor(struct inotify_private *in)
{
        close(in->fd);
        return 0;
}


/*
  see if a particular event from inotify really does match a requested
  notify event in SMB
*/
static BOOL filter_match(struct inotify_watch_context *w,
                         struct inotify_event *e)
{
        DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n",
                   e->mask, w->mask, w->filter));

        if ((e->mask & w->mask) == 0) {
                /* this happens because inotify_add_watch() coalesces watches on the same
                   path, oring their masks together */
                return False;
        }

        /* SMB separates the filters for files and directories */
        if (e->mask & IN_ISDIR) {
                if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
                        return False;
                }
        } else {
                if ((e->mask & IN_ATTRIB) &&
                    (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
                                  FILE_NOTIFY_CHANGE_LAST_WRITE|
                                  FILE_NOTIFY_CHANGE_LAST_ACCESS|
                                  FILE_NOTIFY_CHANGE_EA|
                                  FILE_NOTIFY_CHANGE_SECURITY))) {
                        return True;
                }
                if ((e->mask & IN_MODIFY) && 
                    (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
                        return True;
                }
                if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
                        return False;
                }
        }

        return True;
}
        


/*
  dispatch one inotify event
  
  the cookies are used to correctly handle renames
*/
static void inotify_dispatch(struct inotify_private *in, 
                             struct inotify_event *e, 
                             uint32_t prev_cookie,
                             struct inotify_event *e2)
{
        struct inotify_watch_context *w, *next;
        struct notify_event ne;

        DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n",
                   e->mask, e->len ? e->name : ""));

        /* ignore extraneous events, such as unmount and IN_IGNORED events */
        if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
                        IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
                return;
        }

        /* map the inotify mask to a action. This gets complicated for
           renames */
        if (e->mask & IN_CREATE) {
                ne.action = NOTIFY_ACTION_ADDED;
        } else if (e->mask & IN_DELETE) {
                ne.action = NOTIFY_ACTION_REMOVED;
        } else if (e->mask & IN_MOVED_FROM) {
                if (e2 != NULL && e2->cookie == e->cookie) {
                        ne.action = NOTIFY_ACTION_OLD_NAME;
                } else {
                        ne.action = NOTIFY_ACTION_REMOVED;
                }
        } else if (e->mask & IN_MOVED_TO) {
                if (e->cookie == prev_cookie) {
                        ne.action = NOTIFY_ACTION_NEW_NAME;
                } else {
                        ne.action = NOTIFY_ACTION_ADDED;
                }
        } else {
                ne.action = NOTIFY_ACTION_MODIFIED;
        }
        ne.path = e->name;

        DEBUG(10, ("inotify_dispatch: ne.action = %d, ne.path = %s\n",
                   ne.action, ne.path));

        /* find any watches that have this watch descriptor */
        for (w=in->watches;w;w=next) {
                next = w->next;
                if (w->wd == e->wd && filter_match(w, e)) {
                        w->callback(in->ctx, w->private_data, &ne);