1 files changed, 457 insertions, 0 deletions

diff --git a/source3/smbd/notify_inotify.c b/source3/smbd/notify_inotify.c
new file mode 100644
index 0000000..81fafc2
--- /dev/null
+++ b/source3/smbd/notify_inotify.c
@@ -0,0 +1,457 @@
+/* 
+   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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+  notify implementation using inotify
+*/
+
+#include "includes.h"
+#include "../librpc/gen_ndr/notify.h"
+#include "smbd/smbd.h"
+#include "lib/util/sys_rw_data.h"
+
+#include <sys/inotify.h>
+
+/* glibc < 2.5 headers don't have these defines */
+#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,
+			 uint32_t filter);
+	void *private_data;
+	uint32_t mask; /* the inotify mask */
+	uint32_t filter; /* the windows completion filter */
+	const char *path;
+};
+
+
+/*
+  map from a change notify mask to a inotify mask. Remove any bits
+  which we can handle
+*/
+static const struct {
+	uint32_t notify_mask;
+	uint32_t inotify_mask;
+} inotify_mapping[] = {
+	{FILE_NOTIFY_CHANGE_FILE_NAME,   IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
+	{FILE_NOTIFY_CHANGE_DIR_NAME,    IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
+	{FILE_NOTIFY_CHANGE_ATTRIBUTES,  IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
+	{FILE_NOTIFY_CHANGE_LAST_WRITE,  IN_ATTRIB},
+	{FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
+	{FILE_NOTIFY_CHANGE_EA,          IN_ATTRIB},
+	{FILE_NOTIFY_CHANGE_SECURITY,    IN_ATTRIB}
+};
+
+static uint32_t inotify_map(uint32_t *filter)
+{
+	size_t i;
+	uint32_t out=0;
+	for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
+		if (inotify_mapping[i].notify_mask & *filter) {
+			out |= inotify_mapping[i].inotify_mask;
+			*filter &= ~inotify_mapping[i].notify_mask;
+		}
+	}
+	return out;
+}
+
+/*
+ * Map inotify mask back to filter. This returns all filters that
+ * could have created the inotify watch.
+ */
+static uint32_t inotify_map_mask_to_filter(uint32_t mask)
+{
+	size_t i;
+	uint32_t filter = 0;
+
+	for (i = 0; i < ARRAY_SIZE(inotify_mapping); i++) {
+		if (inotify_mapping[i].inotify_mask & mask) {
+			filter |= inotify_mapping[i].notify_mask;
+		}
+	}
+
+	if (mask & IN_ISDIR) {
+		filter &= ~FILE_NOTIFY_CHANGE_FILE_NAME;
+	} else {
+		filter &= ~FILE_NOTIFY_CHANGE_DIR_NAME;
+	}
+
+	return filter;
+}
+
+/*
+  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)
+{
+	bool ok;
+
+	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) {
+		ok = ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) != 0);
+		return ok;
+	}
+
+	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;
+	}
+
+	ok = ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) != 0);
+	return ok;
+}
+
+
+
+/*
+  dispatch one inotify event
+
+  the cookies are used to correctly handle renames
+*/
+static void inotify_dispatch(struct inotify_private *in, 
+			     struct inotify_event *e, 
+			     int prev_wd,
+			     uint32_t prev_cookie,
+			     struct inotify_event *e2)
+{
+	struct inotify_watch_context *w, *next;
+	struct notify_event ne;
+	uint32_t filter;
+
+	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 &&
+		    e2->wd == e->wd) {
+			ne.action = NOTIFY_ACTION_OLD_NAME;
+		} else {
+			ne.action = NOTIFY_ACTION_REMOVED;
+		}
+	} else if (e->mask & IN_MOVED_TO) {
+		if ((e->cookie == prev_cookie) && (e->wd == prev_wd)) {
+			ne.action = NOTIFY_ACTION_NEW_NAME;
+		} else {
+			ne.action = NOTIFY_ACTION_ADDED;
+		}
+	} else {
+		ne.action = NOTIFY_ACTION_MODIFIED;
+	}
+	ne.path = e->name;
+
+	filter = inotify_map_mask_to_filter(e->mask);
+
+	DBG_DEBUG("ne.action = %d, ne.path = %s, filter = %d\n",
+		  ne.action, ne.path, filter);
+
+	/* 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)) {
+			ne.dir = w->path;
+			w->callback(in->ctx, w->private_data, &ne, filter);
+		}
+	}
+
+	if ((ne.action == NOTIFY_ACTION_NEW_NAME) &&
+	    ((e->mask & IN_ISDIR) == 0)) {
+
+		/*
+		 * SMB expects a file rename to generate three events, two for
+		 * the rename and the other for a modify of the
+		 * destination. Strange!
+		 */
+
+		ne.action = NOTIFY_ACTION_MODIFIED;
+		e->mask = IN_ATTRIB;
+
+		for (w=in->watches;w;w=next) {
+			next = w->next;
+			if (w->wd == e->wd && filter_match(w, e) &&
+			    !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
+				ne.dir = w->path;
+				w->callback(in->ctx, w->private_data, &ne,
+					    filter);
+			}
+		}
+	}
+}
+
+/*
+  called when the kernel has some events for us
+*/
+static void inotify_handler(struct tevent_context *ev, struct tevent_fd *fde,
+			    uint16_t flags, void *private_data)
+{
+	struct inotify_private *in = talloc_get_type(private_data,
+						     struct inotify_private);
+	int bufsize = 0;
+	struct inotify_event *e0, *e;
+	uint32_t prev_cookie=0;
+	int prev_wd = -1;
+	ssize_t ret;
+
+	/*
+	  we must use FIONREAD as we cannot predict the length of the
+	  filenames, and thus can't know how much to allocate
+	  otherwise
+	*/
+	if (ioctl(in->fd, FIONREAD, &bufsize) != 0 || 
+	    bufsize == 0) {
+		DEBUG(0,("No data on inotify fd?!\n"));
+		TALLOC_FREE(fde);
+		return;
+	}
+
+	e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize + 1);
+	if (e == NULL) return;
+	((uint8_t *)e)[bufsize] = '\0';
+
+	ret = read_data(in->fd, e0, bufsize);
+	if (ret != bufsize) {
+		DEBUG(0, ("Failed to read all inotify data - %s\n",
+			  strerror(errno)));
+		talloc_free(e0);
+		/* the inotify fd will now be out of sync,
+		 * can't keep reading data off it */
+		TALLOC_FREE(fde);
+		return;
+	}
+
+	/* we can get more than one event in the buffer */
+	while (e && (bufsize >= sizeof(*e))) {
+		struct inotify_event *e2 = NULL;
+		bufsize -= e->len + sizeof(*e);
+		if (bufsize >= sizeof(*e)) {
+			e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
+		}
+		inotify_dispatch(in, e, prev_wd, prev_cookie, e2);
+		prev_wd = e->wd;
+		prev_cookie = e->cookie;
+		e = e2;
+	}
+
+	talloc_free(e0);
+}
+
+/*
+  setup the inotify handle - called the first time a watch is added on
+  this context
+*/
+static int inotify_setup(struct sys_notify_context *ctx)
+{
+	struct inotify_private *in;
+	struct tevent_fd *fde;
+
+	in = talloc(ctx, struct inotify_private);
+	if (in == NULL) {
+		return ENOMEM;
+	}
+
+	in->fd = inotify_init();
+	if (in->fd == -1) {
+		int ret = errno;
+		DEBUG(0, ("Failed to init inotify - %s\n", strerror(ret)));
+		talloc_free(in);
+		return ret;
+	}
+	in->ctx = ctx;
+	in->watches = NULL;
+
+	ctx->private_data = in;
+	talloc_set_destructor(in, inotify_destructor);
+
+	/* add a event waiting for the inotify fd to be readable */
+	fde = tevent_add_fd(ctx->ev, in, in->fd, TEVENT_FD_READ,
+			    inotify_handler, in);
+	if (fde == NULL) {
+		ctx->private_data = NULL;
+		TALLOC_FREE(in);
+		return ENOMEM;
+	}
+	return 0;
+}
+
+/*
+  destroy a watch
+*/
+static int watch_destructor(struct inotify_watch_context *w)
+{
+	struct inotify_private *in = w->in;
+	int wd = w->wd;
+	DLIST_REMOVE(w->in->watches, w);
+
+	for (w=in->watches;w;w=w->next) {
+		if (w->wd == wd) {
+			/*
+			 * Another inotify_watch_context listens on this path,
+			 * leave the kernel level watch in place
+			 */
+			return 0;
+		}
+	}
+
+	DEBUG(10, ("Deleting inotify watch %d\n", wd));
+	if (inotify_rm_watch(in->fd, wd) == -1) {
+		DEBUG(1, ("inotify_rm_watch returned %s\n", strerror(errno)));
+	}
+	return 0;
+}
+
+
+/*
+  add a watch. The watch is removed when the caller calls
+  talloc_free() on *handle
+*/
+int inotify_watch(TALLOC_CTX *mem_ctx,
+		  struct sys_notify_context *ctx,
+		  const char *path,
+		  uint32_t *filter,
+		  uint32_t *subdir_filter,
+		  void (*callback)(struct sys_notify_context *ctx,
+				   void *private_data,
+				   struct notify_event *ev,
+				   uint32_t filter),
+		  void *private_data,
+		  void *handle_p)
+{
+	struct inotify_private *in;
+	uint32_t mask;
+	struct inotify_watch_context *w;
+	uint32_t orig_filter = *filter;
+	void **handle = (void **)handle_p;
+
+	/* maybe setup the inotify fd */
+	if (ctx->private_data == NULL) {
+		int ret;
+		ret = inotify_setup(ctx);
+		if (ret != 0) {
+			return ret;
+		}
+	}
+
+	in = talloc_get_type(ctx->private_data, struct inotify_private);
+
+	mask = inotify_map(filter);
+	if (mask == 0) {
+		/* this filter can't be handled by inotify */
+		return EINVAL;
+	}
+
+	/* using IN_MASK_ADD allows us to cope with inotify() returning the same
+	   watch descriptor for multiple watches on the same path */
+	mask |= (IN_MASK_ADD | IN_ONLYDIR);
+
+	w = talloc(mem_ctx, struct inotify_watch_context);
+	if (w == NULL) {
+		*filter = orig_filter;
+		return ENOMEM;
+	}
+
+	w->in = in;
+	w->callback = callback;
+	w->private_data = private_data;
+	w->mask = mask;
+	w->filter = orig_filter;
+	w->path = talloc_strdup(w, path);
+	if (w->path == NULL) {
+		*filter = orig_filter;
+		TALLOC_FREE(w);
+		return ENOMEM;
+	}
+
+	/* get a new watch descriptor for this path */
+	w->wd = inotify_add_watch(in->fd, path, mask);
+	if (w->wd == -1) {
+		int err = errno;
+		*filter = orig_filter;
+		TALLOC_FREE(w);
+		DEBUG(1, ("inotify_add_watch returned %s\n", strerror(err)));
+		return err;
+	}
+
+	DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n",
+		   path, mask, w->wd));
+
+	(*handle) = w;
+
+	DLIST_ADD(in->watches, w);
+
+	/* the caller frees the handle to stop watching */
+	talloc_set_destructor(w, watch_destructor);
+
+	return 0;
+}