r14616: added notify change support to the posix backend

It doesn't fully work yet, and doesn't yet have all the efficiency
that is planned, but it doesn't break anything and I wanted to get the
code in the tree to minimise the chance of collisions with the work
metze is doing.
(This used to be commit 1624ea88e6eef89caacc36e7513aa79df0d579b9)

1 files changed, 402 insertions, 0 deletions

diff --git a/source4/ntvfs/common/notify.c b/source4/ntvfs/common/notify.c
new file mode 100644
index 0000000000..48b3559b36
--- /dev/null
+++ b/source4/ntvfs/common/notify.c
@@ -0,0 +1,402 @@
+/* 
+   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.
+*/
+
+/*
+  this is the change notify database. It implements mechanisms for
+  storing current change notify waiters in a tdb, and checking if a
+  given event matches any of the stored notify waiiters.
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "lib/tdb/include/tdb.h"
+#include "lib/tdb/include/tdbutil.h"
+#include "messaging/messaging.h"
+#include "db_wrap.h"
+#include "smb_server/smb_server.h"
+#include "lib/messaging/irpc.h"
+#include "librpc/gen_ndr/ndr_notify.h"
+#include "dlinklist.h"
+
+struct notify_context {
+	struct tdb_wrap *w;
+	uint32_t server;
+	struct messaging_context *messaging_ctx;
+	struct notify_list *list;
+	struct notify_array *array;
+};
+
+
+struct notify_list {
+	struct notify_list *next, *prev;
+	void *private;
+	void (*callback)(void *, const struct notify_event *);
+};
+
+#define NOTIFY_KEY "notify array"
+
+static NTSTATUS notify_remove_all(struct notify_context *notify);
+static void notify_handler(struct messaging_context *msg_ctx, void *private, 
+			   uint32_t msg_type, uint32_t server_id, DATA_BLOB *data);
+
+/*
+  destroy the notify context
+*/
+static int notify_destructor(void *p)
+{
+	struct notify_context *notify = talloc_get_type(p, struct notify_context);
+	messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
+	notify_remove_all(notify);
+	return 0;
+}
+
+/*
+  Open up the notify.tdb database. You should close it down using
+  talloc_free(). We need the messaging_ctx to allow for notifications
+  via internal messages
+*/
+struct notify_context *notify_init(TALLOC_CTX *mem_ctx, uint32_t server, 
+				   struct messaging_context *messaging_ctx)
+{
+	char *path;
+	struct notify_context *notify;
+
+	notify = talloc(mem_ctx, struct notify_context);
+	if (notify == NULL) {
+		return NULL;
+	}
+
+	path = smbd_tmp_path(notify, "notify.tdb");
+	notify->w = tdb_wrap_open(notify, path, 0,  
+			       TDB_DEFAULT,
+			       O_RDWR|O_CREAT, 0600);
+	talloc_free(path);
+	if (notify->w == NULL) {
+		talloc_free(notify);
+		return NULL;
+	}
+
+	notify->server = server;
+	notify->messaging_ctx = messaging_ctx;
+	notify->list = NULL;
+	notify->array = NULL;
+
+	talloc_set_destructor(notify, notify_destructor);
+
+	/* register with the messaging subsystem for the notify
+	   message type */
+	messaging_register(notify->messaging_ctx, notify, 
+			   MSG_PVFS_NOTIFY, notify_handler);
+
+	return notify;
+}
+
+/*
+  load the notify array
+*/
+static NTSTATUS notify_load(struct notify_context *notify)
+{
+	TDB_DATA dbuf;
+	DATA_BLOB blob;
+	NTSTATUS status;
+
+	talloc_free(notify->array);
+	notify->array = talloc_zero(notify, struct notify_array);
+	NT_STATUS_HAVE_NO_MEMORY(notify->array);
+
+	dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
+	if (dbuf.dptr == NULL) {
+		return NT_STATUS_OK;
+	}
+
+	blob.data = dbuf.dptr;
+	blob.length = dbuf.dsize;
+
+	status = ndr_pull_struct_blob(&blob, notify->array, notify->array, 
+				      (ndr_pull_flags_fn_t)ndr_pull_notify_array);
+	free(dbuf.dptr);
+
+	return status;
+}
+
+
+/*
+  save the notify array
+*/
+static NTSTATUS notify_save(struct notify_context *notify)
+{
+	TDB_DATA dbuf;
+	DATA_BLOB blob;
+	NTSTATUS status;
+	int ret;
+	TALLOC_CTX *tmp_ctx;
+
+	if (notify->array->num_entries == 0) {
+		ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
+		if (ret != 0) {
+			return NT_STATUS_INTERNAL_DB_CORRUPTION;
+		}
+		return NT_STATUS_OK;
+	}
+
+	tmp_ctx = talloc_new(notify);
+
+	status = ndr_push_struct_blob(&blob, tmp_ctx, notify->array, 
+				      (ndr_push_flags_fn_t)ndr_push_notify_array);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return status;
+	}
+
+	dbuf.dptr = blob.data;
+	dbuf.dsize = blob.length;
+		
+	ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
+	talloc_free(tmp_ctx);
+	if (ret != 0) {
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	return NT_STATUS_OK;
+}
+
+
+/*
+  handle incoming notify messages
+*/
+static void notify_handler(struct messaging_context *msg_ctx, void *private, 
+			   uint32_t msg_type, uint32_t server_id, DATA_BLOB *data)
+{
+	struct notify_context *notify = talloc_get_type(private, struct notify_context);
+	NTSTATUS status;
+	struct notify_event ev;
+	TALLOC_CTX *tmp_ctx = talloc_new(notify);
+	struct notify_list *listel;
+
+	status = ndr_pull_struct_blob(data, tmp_ctx, &ev, 
+				      (ndr_pull_flags_fn_t)ndr_pull_notify_event);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return;
+	}
+
+	for (listel=notify->list;listel;listel=listel->next) {
+		if (listel->private == ev.private) {
+			listel->callback(listel->private, &ev);
+			break;
+		}
+	}
+
+	talloc_free(tmp_ctx);	
+}
+
+/*
+  add a notify watch. This is called when a notify is first setup on a open
+  directory handle.
+*/
+NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e,
+		    void (*callback)(void *, const struct notify_event *), 
+		    void *private)
+{
+	NTSTATUS status;
+	struct notify_list *listel;
+
+	status = notify_load(notify);
+	NT_STATUS_NOT_OK_RETURN(status);
+
+	notify->array->entries = talloc_realloc(notify->array, notify->array->entries, 
+						struct notify_entry,
+						notify->array->num_entries+1);
+
+	if (notify->array->entries == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	notify->array->entries[notify->array->num_entries] = *e;
+	notify->array->entries[notify->array->num_entries].private = private;
+	notify->array->entries[notify->array->num_entries].server = notify->server;
+	notify->array->num_entries++;
+
+	status = notify_save(notify);
+	NT_STATUS_NOT_OK_RETURN(status);
+
+	listel = talloc(notify, struct notify_list);
+	NT_STATUS_HAVE_NO_MEMORY(listel);
+
+	listel->private = private;
+	listel->callback = callback;
+	DLIST_ADD(notify->list, listel);
+
+	return status;
+}
+
+/*
+  remove a notify watch. Called when the directory handle is closed
+*/
+NTSTATUS notify_remove(struct notify_context *notify, void *private)
+{
+	NTSTATUS status;
+	struct notify_list *listel;
+	int i;
+
+	for (listel=notify->list;listel;listel=listel->next) {
+		if (listel->private == private) {
+			DLIST_REMOVE(notify->list, listel);
+			break;
+		}
+	}
+	if (listel == NULL) {
+		return NT_STATUS_OBJECT_NAME_NOT_FOUND;
+	}
+
+	status = notify_load(notify);
+	NT_STATUS_NOT_OK_RETURN(status);
+
+	for (i=0;i<notify->array->num_entries;i++) {
+		if (notify->server == notify->array->entries[i].server && 
+		    private == notify->array->entries[i].private) {
+			break;
+		}
+	}
+	if (i == notify->array->num_entries) {
+		return NT_STATUS_OBJECT_NAME_NOT_FOUND;
+	}
+
+	if (i < notify->array->num_entries-1) {
+		memmove(&notify->array->entries[i], &notify->array->entries[i+1], 
+			sizeof(notify->array->entries[i])*(notify->array->num_entries-(i+1)));
+	}
+	notify->array->num_entries--;
+
+	return notify_save(notify);
+}
+
+/*
+  remove all notify watches for this messaging server
+*/
+static NTSTATUS notify_remove_all(struct notify_context *notify)
+{
+	NTSTATUS status;
+	int i;
+
+	if (notify->list == NULL) {
+		return NT_STATUS_OK;
+	}
+
+	status = notify_load(notify);
+	NT_STATUS_NOT_OK_RETURN(status);
+
+	for (i=0;i<notify->array->num_entries;i++) {
+		if (notify->server == notify->array->entries[i].server) {
+			if (i < notify->array->num_entries-1) {
+				memmove(&notify->array->entries[i], &notify->array->entries[i+1], 
+					sizeof(notify->array->entries[i])*(notify->array->num_entries-(i+1)));
+			}
+			i--;
+			notify->array->num_entries--;
+		}
+	}
+
+
+	return notify_save(notify);
+}
+
+
+/*
+  see if a notify event matches
+*/
+static BOOL notify_match(struct notify_context *notify, struct notify_entry *e,
+			 const char *path, uint32_t action)
+{
+	size_t len = strlen(e->path);
+
+	/* TODO: check action */
+
+	if (strncmp(path, e->path, len) != 0) {
+		return False;
+	}
+
+	if (path[len] == 0) {
+		return True;
+	}
+	if (path[len] != '/') {
+		return False;
+	}
+
+	if (!e->recursive) {
+		if (strchr(&path[len+1], '/') != NULL) {
+			return False;
+		}
+	}
+
+	return True;
+}
+
+
+/*
+  send a notify message to another messaging server
+*/
+static void notify_send(struct notify_context *notify, struct notify_entry *e,
+			const char *path, uint32_t action)
+{
+	struct notify_event ev;
+	DATA_BLOB data;
+	NTSTATUS status;
+	TALLOC_CTX *tmp_ctx;
+
+	ev.action = action;
+	ev.path = path;
+	ev.private = e->private;
+
+	tmp_ctx = talloc_new(notify);
+
+	status = ndr_push_struct_blob(&data, tmp_ctx, &ev, 
+				      (ndr_push_flags_fn_t)ndr_push_notify_event);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return;
+	}
+
+	status = messaging_send(notify->messaging_ctx, e->server, 
+				MSG_PVFS_NOTIFY, &data);
+	talloc_free(tmp_ctx);
+}
+
+/*
+  trigger a notify message for anyone waiting on a matching event
+*/
+void notify_trigger(struct notify_context *notify,
+		    uint32_t action, const char *path)
+{
+	NTSTATUS status;
+	int i;
+
+	status = notify_load(notify);
+	if (!NT_STATUS_IS_OK(status)) {
+		return;
+	}
+
+	/* this needs to be changed to a log(n) search */
+	for (i=0;i<notify->array->num_entries;i++) {
+		if (notify_match(notify, &notify->array->entries[i], path, action)) {
+			notify_send(notify, &notify->array->entries[i], path, action);
+		}
+	}
+}